CRADLE-TO-GATE LIFE CYCLE ANALYSIS OF … of EPS Resin LCA 2017.pdfETHYLBENZENE/STYRENE PRODUCTION...

CRADLE-TO-GATE LIFE CYCLE ANALYSIS OF EXPANDED POLYSTYRENE RESIN

Final Report

Submitted to:

EPS Industry Alliance

Submitted by:

Franklin Associates, A Division of ERG

Date:

December 2016

CLIENT\EPS-IA\KC162652

12.28.16 4004.00.002 ii

PREFACE

The report that follows is a life cycle assessment of expanded polystyrene (EPS) resin.

Funding for this project was provided by the EPS Industry Alliance (EPS IA). The report

was made possible through the cooperation of EPS IA member companies who provided

data for the production of EPS resin.

At Franklin Associates, A Division of ERG, the project was managed and primarily authored

by Melissa Huff, Senior Chemical Engineer. Janet Mosley provided assistance with modeling

and analysis. Anne Marie Molen assisted with data collection tasks and report preparation.

Franklin Associates gratefully acknowledges the significant contribution to this project by

Elizabeth Steiner and Diana Gentilcore of EPS IA in leading this project. Also acknowledged

are companies, Plasti-Fab Ltd., NOVA, and Styropek, who graciously provided the EPS resin

LCI data. Their effort in collecting data has added considerably to the quality of this LCA

report.

This report was prepared for EPS IA by Franklin Associates, A Division of Eastern Research

Group, Inc. (ERG) as an independent contractor. Franklin Associates makes no statements

other than those presented within the report.

December, 2016


12.28.16 4004.00.002 iii

TABLE OF CONTENTS

INTRODUCTION .......................................................................................................................................................................... 1

STUDY GOAL AND SCOPE ........................................................................................................................................................ 2

STUDY GOAL AND INTENDED USE ................................................................................................................................................... 3

FUNCTIONAL UNIT ................................................................................................................................................................................... 3

SCOPE AND BOUNDARIES ..................................................................................................................................................................... 3

INVENTORY AND IMPACT ASSESSMENT RESULTS CATEGORIES...................................................................................... 6

DATA SOURCES .......................................................................................................................................................................................... 8

DATA QUALITY ASSESSMENT ............................................................................................................................................................. 9

DATA ACCURACY AND UNCERTAINTY ......................................................................................................................................... 10

METHOD ...................................................................................................................................................................................................... 10

LIFE CYCLE INVENTORY AND IMPACT ASSESSMENT RESULTS .............................................................................. 14

ENERGY DEMAND ................................................................................................................................................................................... 14

SOLID WASTE ........................................................................................................................................................................................... 18

WATER CONSUMPTION ....................................................................................................................................................................... 19

GLOBAL WARMING POTENTIAL ...................................................................................................................................................... 20

ACIDIFICATION ........................................................................................................................................................................................ 21

EUTROPHICATION .................................................................................................................................................................................. 23

OZONE DEPLETION ................................................................................................................................................................................ 24

SMOG FORMATION ................................................................................................................................................................................. 25

APPENDIX: EXPANDED POLYSTYRENE (EPS) MANUFACTURE ............................................................................. 27

CRUDE OIL PRODUCTION ................................................................................................................................................................... 27

PETROLEUM REFINING (DISTILLATION, DESALTING, AND HYDROTREATING) ..................................................... 29

NATURAL GAS PRODUCTION ............................................................................................................................................................ 33

NATURAL GAS PROCESSING .............................................................................................................................................................. 37

OLEFINS PRODUCTION (ETHYLENE/PYGAS) ............................................................................................................................ 37

BENZENE PRODUCTION ...................................................................................................................................................................... 42

ETHYLBENZENE/STYRENE PRODUCTION ................................................................................................................................. 44

PENTANE PRODUCTION ...................................................................................................................................................................... 46

EXPANDED POLYSTYRENE RESIN PRODUCTION .................................................................................................................... 46

REFERENCES ............................................................................................................................................................................................. 48


12.28.16 4004.00.002 1

CRADLE-TO-GATE LIFE CYCLE ANALYSIS OF EXPANDED POLYSTYRENE RESIN

INTRODUCTION

This study was conducted to provide the EPS Industry Alliance (EPS IA), their members,

users of the U.S. LCI Database, and the public at large with information about the life cycle

inventory and impacts for average expanded polystyrene (EPS) resin as used within a

variety of products in North America. Life cycle assessment (LCA) is recognized as a

scientific method for making comprehensive, quantified evaluations of the environmental

benefits and tradeoffs commonly for the entire life cycle of a product system, beginning

with raw material extraction and continuing through disposition at the end of its useful life

as shown in Figure 1 below. This cradle-to-gate LCI and LCA analysis includes the life cycle

stages shown in the dashed box including the Raw Materials Acquisition and Materials

Manufacture boxes in the figure.

Figure 1. General materials flow for cradle-to-grave analysis of a product system.

The dashed box indicates the boundaries of this analysis.

The results of this analysis are useful for understanding production-related impacts and

are provided in a manner suitable for incorporation into full life cycle assessment studies.

The information from an LCA can be used as the basis for further study of the potential

improvement of resource use and environmental impacts associated with product systems.

It can also pinpoint areas (e.g., material components or processes) where changes would be

most beneficial in terms of reducing energy use or potential impacts.

The cradle-to-gate life cycle inventory (LCI) and impact assessment (LCIA) presented in

this study quantifies the total energy requirements, energy sources, water consumption,

atmospheric pollutants, waterborne pollutants, and solid waste resulting from the


12.28.16 4004.00.002 2

production of expanded polystyrene resin. It is considered a cradle-to-gate boundary

system because this analysis ends at the resin production. The system boundaries stop at

resin production so that the resin data can be linked with fabrication, use, and end-of-life

data to create full life cycle inventories for a variety of EPS products, such as insulation or

packaging. The method used for this inventory has been conducted following

internationally accepted standards for LCI and LCA methodology as outlined in the ISO

14040 and 14044 standard documents1.

A life cycle assessment (LCA) commonly examines the sequence of steps in the life cycle of

a product system, beginning with raw material extraction and continuing on through

material production, product fabrication, use, reuse or recycling where applicable, and final

disposition. This LCA boundary ends at material production. An LCA consists of four

phases:

Goal and scope definition

Life cycle inventory (LCI)

Life cycle impact assessment (LCIA)

Interpretation of results

The LCI identifies and quantifies the material inputs, energy consumption, water

consumption, and environmental emissions (atmospheric emissions, waterborne wastes,

and solid wastes) over the defined scope of the study. The LCI data for this analysis of EPS

resin is shown separately as unit processes and as a cradle-to-gate dataset in the attached

Appendix. Those unit processes that have been updated will be made available to the

National Renewable Energy Laboratory (NREL) who maintains the U.S. LCI Database.

In the LCIA phase, the inventory of emissions is classified into categories in which the

emissions may contribute to impacts on human health or the environment. Within each

impact category, the emissions are then normalized to a common reporting basis, using

characterization factors that express the impact of each substance relative to a reference

substance.

STUDY GOAL AND SCOPE

In this section, the goal and scope of the study is defined, including information on data

sources used and methodology.

1 International Standards Organization. ISO 14040:2006 Environmental managementLife cycle

assessmentPrinciples and framework, ISO 14044:2006, Environmental management Life cycle

assessment Requirements and guidelines.


12.28.16 4004.00.002 3

STUDY GOAL AND INTENDED USE

The purpose of this LCA is to document the LCI data and then evaluate the environmental

profiles of expanded polystyrene resin. The intended use of the study results is twofold:

To provide the LCA community and other interested parties with average

North American LCI data for EPS resin, and

to provide information about the environmental burdens associated with the

production of EPS resin. The LCA results for the EPS resin system can be used

as a benchmark for evaluating future updated EPS resin results for North

America.

The LCA has been conducted following internationally accepted standards for LCA as

outlined in the ISO 14040 and 14044 standards2. As there are no comparisons made and so

no comparative assertions, a panel peer review is not required for this study.

This report is the property of EPS IA and may be used by the trade association or members

or the general public at EPS IAs discretion.

FUNCTIONAL UNIT

The function of EPS resin is its availability to be used in a number of EPS products, for

example insulation and packaging. As the boundaries only include through material

manufacture, a mass functional unit has been chosen. Results for this analysis are shown on

both a 1,000 pound and a 1,000 kilogram basis.

SCOPE AND BOUNDARIES

This LCA quantifies energy and resource use, water consumption, solid waste, and

environmental impacts for the following steps in the life cycle of the EPS resin:

Raw material extraction (e.g., extraction of petroleum and natural gas as feedstocks for

plastic resin), and intermediate material processing, including incoming transportation for

each process, and

EPS resin manufacture, including incoming transportation for each process.

This report presents LCI results, as well as LCA results, for the production of EPS resin. Figure 2

presents the flow diagram for the production of EPS resin. Process descriptions and individual

process tables for each box shown in the flow diagram can be found in the attached appendix.

Primary data has been collected for EPS resin production for the year 2015. Primary data was

2 International Standards Organization. ISO 14040:2006 Environmental managementLife cycle

assessmentPrinciples and framework, ISO 14044:2006, Environmental management Life cycle

assessment Requirements and guidelines.


12.28.16 4004.00.002 4

Figure 2. Flow diagram for the production of expanded polystyrene (EPS) resin.

From Petroleum

Refining Pentane

Production

Expanded

Polystyrene

Manufacture

Natural Gas

Production

Natural Gas

Processing

Crude Oil

Production

Olefins

(Ethylene/Pygas)

Production

Petroleum Refining

(Distillation/Desalting

/Hydrotreating)

Ethylbenzene/Styrene

Production

Benzene Production

(catalytic reforming

and pyrolysis

gasoline)


12.28.16 4004.00.002 5

collected between 2004 and 2006 for olefins, benzene, ethylbenzene/styrene in the ACC Plastics

Division study, Cradle-to-Gate Life Cycle Inventory of Nine Plastic Resins and Four

Polyurethane Precursors.3 All other processes shown in Figure 2 are provided using secondary

data, which is discussed in the Appendix of this report. All raw and intermediate data sets, except

pentane, are currently being updated for the ACC Plastics Division and will be available in 2017.

The following are not included in the study:

Miscellaneous materials and additives. Selected materials such as catalysts, pigments,

or other additives which total less than one percent by weight of the net process inputs are

typically not included in the assessment. Omitting miscellaneous materials and additives

helps keep the scope of the study focused and manageable within budget and time

constraints. It is possible that production of some substances used in small amounts may

be energy and resource intensive or may release toxic emissions; however, the impacts

would have to be very large in proportion to their mass in order to significantly affect

overall results and conclusions. For this study, no use of resource-intensive or high-

toxicity chemicals or additives was identified. Therefore, the results for the resin are not

expected to be understated by any significant amount due to substances that may be used

in small amounts.

Capital equipment, facilities, and infrastructure. The energy and wastes associated

with the manufacture of buildings, roads, pipelines, motor vehicles, industrial machinery,

etc. are not included. The energy and emissions associated with production of capital

equipment, facilities, and infrastructure generally become negligible when averaged over

the total output of product or service provided over their useful lifetimes.

Space conditioning. The fuels and power consumed to heat, cool, and light

manufacturing establishments are omitted from the calculations in most cases. For

manufacturing plants that carry out thermal processing or otherwise consume large

amounts of energy, space conditioning energy is quite low compared to process energy.

The data collection forms developed for this project specifically requested that the data

provider exclude energy use for space conditioning, or indicate if the reported energy

requirements included space conditioning. Energy use for space conditioning, lighting,

and other overhead activities is not expected to make a significant contribution to total

energy use for the resin system.

Support personnel requirements. The energy and wastes associated with research and

development, sales, and administrative personnel or related activities have not been

included in this study. Similar to space conditioning, energy requirements and related

emissions are assumed to be quite small for support personnel activities.

The geographic scope of the analysis is the manufacture of EPS resin in North America. The

majority of the data used in the modeling is from North American databases (U.S. LCI

database, Franklin Associates private database). In cases where it was necessary to use

supplemental data from a European database, the data sets were adapted to the extent

possible to represent North American inputs and practices.

3 ACC Plastics Division. Cradle-to-Gate Life Cycle Inventory of Nine Plastic Resins and Four Polyurethane

Precursors. August 2011. Found at https://plastics.americanchemistry.com/LifeCycle-Inventory-of-9-Plastics-

Resins-and-4-Polyurethane-Precursors-Rpt-Only/


12.28.16 4004.00.002 6

INVENTORY AND IMPACT ASSESSMENT RESULTS CATEGORIES

The full inventory of emissions generated in an LCA study is lengthy and diverse, making it

difficult to interpret emissions profiles in a concise and meaningful manner. Life cycle

impact assessment (LCIA) helps with interpretation of the emissions inventory. LCIA is

defined in ISO 14044 Section 3.4 as the phase of life cycle assessment aimed at

understanding and evaluating the magnitude and significance of the potential

environmental impacts for a product system throughout the life cycle of the product. In

the LCIA phase, the inventory of emissions is first classified into categories in which the

emissions may contribute to impacts on human health or the environment. Within each

impact category, the emissions are then normalized to a common reporting basis, using

characterization factors that express the impact of each substance relative to a reference

substance.

The LCI and LCIA results categories and methods applied in this study are displayed in

Table 1. This study addresses global, regional, and local impact categories. For most of the

impact categories examined, the TRACI 2.1 method, developed by the United States

Environmental Protection Agency (EPA) specific to U.S. conditions and updated in 2012, is

employed.4 For the category of Global Warming Potential (GWP), contributing elementary

flows are characterized using factors reported by the Intergovernmental Panel on Climate

Change (IPCC) in 2013 with a 100 year time horizon.5 In addition, some life cycle inventory

(LCI) results are included in the results reported in the analysis:

Energy demand: this method is not an impact assessment, but rather is a cumulative

inventory of all forms of energy used for processing energy, transportation energy,

and feedstock energy. This analysis reports both total energy demand and non-

renewable energy demand. Non-renewable energy demand is reported separately to

assess consumption of fuel resources that can be depleted, while total energy

demand is used as an indicator of overall consumption of resources with energy

value. Energy is also categorized by individual fuel types.

Solid waste is assessed as a sum of the inventory values associated with this

category.

Water consumption is assessed as a sum of the inventory values associated with this

category and does not include any assessment of water scarcity issues.

4 Bare, J. C. Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts

(TRACI), Version 2.1 - Users Manual; EPA/600/R-12/554 2012. 5 IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to

the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 2013.


12.28.16 4004.00.002 7

Table 1. Summary of LCI/LCIA Impact Categories

Impact/InventoryImpact/InventoryImpact/InventoryImpact/Inventory

CategoryCategoryCategoryCategory DescriptionDescriptionDescriptionDescription UnitUnitUnitUnit

LCIA/LCI LCIA/LCI LCIA/LCI LCIA/LCI

MethodologyMethodologyMethodologyMethodology

LCI

Ca

teg

ori

es

LCI

Ca

teg

ori

es

LCI

Ca

teg

ori

es

LCI

Ca

teg

ori

es

Total eTotal eTotal eTotal energy nergy nergy nergy

demanddemanddemanddemand

Measures the total energy from point

of extraction; results include both

renewable and non-renewable

energy sources

MJ Cumulative energy

inventory

NonNonNonNon----renewable renewable renewable renewable

energy demandenergy demandenergy demandenergy demand

Measures the fossil and nuclear

energy from point of extraction MJ

Cumulative energy

inventory

Renewable energy Renewable energy Renewable energy Renewable energy

demanddemanddemanddemand

Measures the hydropower, solar,

wind, and other renewables,

including landfill gas use.

MJ Cumulative energy

inventory

Solid waste by Solid waste by Solid waste by Solid waste by

weightweightweightweight

Measures quantity of fuel, process

and postconsumer waste to a

specific fate (e.g., landfill, WTE) for

final disposal on a mass basis

kg Cumulative solid

waste inventory

Water consumptionWater consumptionWater consumptionWater consumption

Freshwater withdrawals which are

evaporated, incorporated into

products and waste, transferred to

different watersheds, or disposed

into the sea after usage

L

Cumulative water

consumption

inventory

LCIA

Ca

teg

ori

es

LCIA

Ca

teg

ori

es

LCIA

Ca

teg

ori

es

LCIA

Ca

teg

ori

es

Global warming Global warming Global warming Global warming

potentialpotentialpotentialpotential

Represents the heat trapping

capacity of the greenhouse gases.

Important emissions: CO2 fossil, CH4,

N2O

kg CO2

equivalents

(eq)

IPCC (2013) GWP

100a*

Acidification Acidification Acidification Acidification

potential potential potential potential

Quantifies the acidifying effect of

substances on their environment.

Important emissions: SO2, NOx, NH3,

HCl, HF, H2S

kg SO2 eq TRACI v2.1

Eutrophication Eutrophication Eutrophication Eutrophication


Assesses impacts from excessive

load of macro-nutrients to the

environment. Important emissions:

NH3, NOx, COD and BOD, N and P

compounds

kg N eq TRACI v2.1

Ozone depletion Ozone depletion Ozone depletion Ozone depletion


Measures stratospheric ozone

depletion. Important emissions: CFC

compounds and halons

kg CFC-11 eq TRACI v2.1

Smog formation Smog formation Smog formation Smog formation


Determines the formation of reactive

substances (e.g. tropospheric ozone)

that cause harm to human health

and vegetation. Important

emissions: NOx, BTEX, NMVOC, CH4,

C2H6, C4H10, C3H8, C6H14, acetylene,

Et-OH, formaldehyde

kg O3 eq TRACI v2.1


12.28.16 4004.00.002 8

DATA SOURCES

The purpose of this study is to develop a life cycle profile for EPS resin using the most

recent data available for each process. A straight average was calculated from the EPS resin

production data collected from one plant each from three producers in North America

one from Canada, Mexico, and the United States. All companies provided data for the year

2015. As of 2015 there were 8 EPS producers and 10 EPS plants in North America. The

captured production amount is approximately 20 percent of the available capacity for all

expanded polystyrene production in North America. Small amounts (less than 1 percent of

total output) of off-spec resin are produced as coproducts during this process. A mass basis

was used to allocate the credit for the coproducts.

No other primary data was collected for the EPS resin system. However, data used for

ethylene, benzene, and ethylbenzene/styrene were all collected previously by Franklin

Associates for the ACC Plastics Division study, Cradle-to-Gate Life Cycle Inventory of

Nine Plastic Resins and Four Polyurethane Precursors. These datasets will be updated

by the ACC Plastics Division in 2017. Descriptions of the data collected for these 3

intermediate chemicals are provided here.

A weighted average using production quantities was calculated from the olefins production data

collected from three leading producers (8 thermal cracking units) in North America. As of 2003,

there were 16 olefin producers and at least 29 olefin plants in the U.S. The captured production

amount is approximately 30 percent of the available capacity for olefin production. Numerous

coproduct streams are produced from the olefins hydrocracker. Fuel gas and off-gas were two of

the coproducts produced that were exported to another process for fuel. When these fuel

coproducts are exported from the hydrocracker, they carry with them the allocated share of the

inputs and outputs for their production. The separate appendices provide an in-depth discussion

of this allocation. A mass basis was used to allocate the credit to the remaining material

coproducts.

It is estimated that one-third of the benzene production is from pyrolysis gasoline and two-

thirds are produced from catalytic reforming. These percentages were used to weight the

collected datasets for benzene. Catalytic reforming is represented by 2 primary datasets

from 1992. The benzene data collected for this analysis represent 1 producer and 1 plant in

the U.S. using the pyrolysis gasoline production method. As of 2002 there were 22 benzene

producers and 38 benzene plants in the U.S. for the three standard technologies. The

captured production amount is approximately 10 percent of the available capacity for

benzene production in the U.S. Numerous aromatic coproduct streams are produced during

this process. Fuel gas and off-gas were two of the coproducts produced that were exported

to another process for fuel. When these fuel coproducts are exported from the reactor, they

carry with them the allocated share of the inputs and outputs for their production. The

separate appendices provide an in-depth discussion of this allocation. A mass basis was

used to allocate the credit the remaining aromatic products.


12.28.16 4004.00.002 9

Two of the three ethylbenzene/styrene datasets were collected from recent primary

sources for this project and represents 2002-2003 data, while the other dataset comes

from 1993. As of 2001 there were 8 styrene producers and 8 styrene plants in the U.S. The

styrene data collected for this module represent 2 producers and 2 plants in the U.S. The

captured production amount is approximately 25 percent of the available capacity for

styrene production in the U.S. Various coproduct streams are produced during this process.

Coproduct credit was given on a mass basis in the styrene datasets collected during this

analysis.

The remaining raw material and intermediate materials used to produce EPS resin are

from secondary sources. All process descriptions and LCI data for unit processes are

provided in the Appendix.

DATA QUALITY ASSESSMENT

ISO 14044:2006 lists a number of data quality requirements that should be addressed for

studies intended for use in public comparative assertions. The data quality goals for this

analysis were to use data that are (1) geographically representative for the EPS resin based

on the locations where material sourcing and production take place, and (2) representative

of current industry practices in these regions. As described in the previous section, 3

companies each provided current, geographically representative data for one plant

producing the EPS resin.

The background data sets were drawn from either the U.S. LCI database or Ecoinvent. The

data sets used were the most current and most geographically and technologically relevant

data sets available during the data collection phase of the project.

Consistency, Completeness, Precision: Data evaluation procedures and criteria were

applied consistently to all primary data provided by the three EPS resin producers. All

primary data obtained specifically for this study were considered the most representative

available for the systems being studied. Data sets were reviewed for completeness and

material balances, and follow-up was conducted as needed to resolve any questions about

the input and output flows, process technology, etc. The same evaluation process was used

in the development of data sets from Franklins private LCI database that were used in this

analysis.

Reproducibility: To maximize transparency and reproducibility, the report identifies

specific data sources, assumptions, and approaches used in the analysis to the extent

possible; however, reproducibility of study results is limited to some extent by the need to

protect certain data sets that were judged to be the most representative data sets for

modeling purposes but could not be shown due to confidentiality.

Uncertainty: Uncertainty issues and uncertainty thresholds applied in interpreting study

results are described in the following section.


12.28.16 4004.00.002 10

DATA ACCURACY AND UNCERTAINTY

An important issue to consider when using LCA study results is the reliability of the data. In

a complex study with literally thousands of numeric entries, the accuracy of the data and

how it affects conclusions is truly a complex subject, and one that does not lend itself to

standard error analysis techniques. Techniques such as Monte Carlo analysis can be used to

study uncertainty, but the greatest challenge is the lack of uncertainty data or probability

distributions for key parameters, which are often only available as single point estimates.

However, the reliability of the study can be assessed in other ways.

A key question is whether the LCI profiles are accurate and study conclusions are correct.

The accuracy of an environmental profile depends on the accuracy of the numbers that are

combined to arrive at that conclusion. Because of the many processes required to produce

each packaging material, many numbers in the LCI are added together for a total numeric

result. Each number by itself may contribute little to the total, so the accuracy of each

number by itself has a small effect on the overall accuracy of the total. There is no widely

accepted analytical method for assessing the accuracy of each number to any degree of

confidence. For many chemical processes, the data sets are based on actual plant data

reported by plant personnel. The data reported may represent operations for the previous

year or may be representative of engineering and/or accounting methods. All data received

are evaluated to determine whether or not they are representative of the typical industry

practices for that operation or process being evaluated.

There are several other important points with regard to data accuracy. Each number

generally contributes a small part to the total value, so errors within each averaged data

point are generally minor and do not affect the overall analysis of the results. For process

steps that make a larger than average contribution to the total, special care is taken with

the data quality.

There is another dimension to the reliability of the data. Certain numbers do not stand

alone, but rather affect several numbers in the system. An example is the amount of

material required for a process. This number will affect every step in the production

sequence prior to the process. Errors such as this that propagate throughout the system are

more significant in steps that are closest to the end of the production sequence. These data

are reviewed and compared to reliable sources by the practitioner and/or discussed with

the data providers as necessary to assure their accuracy.

In summary, for the particular data sources used and for the specific methodology

described in this report, the results of this report are believed to be as accurate and

reasonable as possible.

METHOD

The LCA has been conducted following internationally accepted standards for LCA as

outlined in the ISO 14040 and 14044 standards, which provide guidance and requirements


12.28.16 4004.00.002 11

for conducting LCA studies. However, for some specific aspects of LCA, the ISO standards

have some flexibility and allow for choices to be made. These include the method used to

allocate inputs and environmental releases among more than one useful product produced

by a process, the method used to account for the energy contained in material feedstocks,

and the method used to allocate environmental burdens for recycled content. The following

sections describe the approach to each issue used in this study. Many of these issues are

specific to the intermediate chemicals used (e.g. olefins from hydrocrackers).

Raw Material Use for Internal Energy

Some of the raw material inputs for the hydrocracker are combusted within the

hydrocracker, which in turn produced an amount of energy, decreasing the amount of

purchased energy required for the reaction. Data providers listed this energy as fuel gas or

offgas and supplied the heating value of this gas. Using this information, Franklin

Associates calculated the amount of raw material combusted within the hydrocracker to

produce offgas energy.

This internal energy is included in the analysis by including the production of the raw

materials combusted to produce the energy as well as the energy amount attributed to the

combustion of those raw materials. Unlike the raw materials that become part of the

product output mass, no material feedstock energy is assigned to the raw materials inputs

that are combusted within the process. Instead they are assigned an Internal offgas use

energy, due to their combustion within the process instead of use to create the plastic resin.

Recovered Energy Exported from System Boundaries

Some of the unit process tables in the appendices shows a line for recovered energy. This

recovered energy is energy (heat or steam) that data providers in the ACC Plastics Division

study reported as being exported from the boundaries of the system, so it would replace

purchased fuels for another process outside the system. Because it is not known what form

of purchased energy the recovered energy would replace, no credit has been given besides

recording the recovered energy amount. Credit is given to the resin/precursor by

subtracting the recovered energy from the process and total energy for a net reduction in

energy.

When fuel coproducts, such as offgas, are exported from the hydrocarbon production, they

carry with them the allocated share of the inputs and outputs for their production. The

ratio of the mass of the exported fuel over the total mass output was removed from the

total inputs and outputs of the process, and the remaining inputs and outputs are allocated

over the material products (Equation 1).

[ ] [ ] productsremainingtoattributedTotal

EO IOM

MIO =

1 (Equation 1)

where

IO = Input/Output Matrix to produce all products/coproducts


12.28.16 4004.00.002 12

MEO = Mass of Exported Offgas

MTotal = Mass of all Products and Coproducts (including fuels)

No energy credit is applied for the exported fuels, since both the inputs and outputs for the

exported fuels have been removed from the data set.

Electricity Grid Fuel Profile

Electricity production and distribution systems in North America are interlinked. Users of

electricity, in general, cannot specify the fuels used to produce their share of the electric

power grid. Data for this analysis was collected from plants in the U.S., Canada, and Mexico.

Although it is possible to use grids specific to Canada, the U.S. and Mexico, horizontal

averaging of data was used for this analysis, which means the three EPS resin data sets

were averaged before linking the fuels to the electricity grid. This was necessary to protect

confidentiality of the data sets collected. After reviewing the differences in the electricity

grids available and noting the use of cogeneration by some plants, the U.S. average fuel

consumption by electrical utilities was assumed for the electricity within this analysis. This

electricity data set uses the eGRID 2010 database.

Electricity generated on-site at a manufacturing facility is represented in the process data

by the fuels used to produce it. In some data sets, a portion of on-site generated electricity

is sold to the electricity grid. Credits for sold on-site electricity are accounted for in the

calculations for the fuel mix.

Electricity/Heat Cogeneration

Cogeneration is the use of steam for generation of both electricity and heat. The most

common configuration is to generate high temperature steam in a cogeneration boiler and

use that steam to generate electricity. The steam exiting the electricity turbines is then

used as a process heat source for other operations. Significant energy savings occur

because in a conventional operation, the steam exiting the electricity generation process is

condensed, and the heat is dissipated to the environment.

For LCI purposes, the fuel consumed and the emissions generated by the cogeneration

boiler need to be allocated to the two energy-consuming processes: electricity generation

and subsequent process steam. An energy basis was used for allocation in this analysis.

In order to allocate fuel consumption and environmental emissions to both electricity and

steam generation, the share of the two forms of energy (electrical and thermal) produced

must be correlated to the quantity of fuel consumed by the boiler. Data on the quantity of

fuel consumed and the associated environmental emissions from the combustion of the

fuel, the amount of electricity generated, and the thermal output of the steam exiting

electricity generation must be known in order to allocate fuel consumption and

environmental emissions accordingly. These three types of data are discussed below.


12.28.16 4004.00.002 13

1. Fuels consumed and emissions generated by the boiler: The majority of

data providers for this study reported natural gas as the fuel used for

cogeneration. According to 2012 industry statistics, natural gas accounted for

65 percent of industrial cogeneration, while coal and waste gases accounted

for the largest portion of the remaining fuels used. For this analysis, the data

for the combustion of natural gas in industrial boilers was used to determine

the environmental emissions from natural gas combustion in cogeneration

boilers. For cases in which coal is used in cogeneration boilers, the data for

the combustion of bituminous coal in industrial boilers is recommended. For

cases in which waste gas is used in cogeneration boilers, the data for the

combustion of LPG (liquefied petroleum gas) in industrial boilers is

recommended.

2. Kilowatt-Hours of Electricity Generated: In this analysis, the data

providers reported the kilowatt-hours of electricity from cogeneration. The

Btu of fuel required for this electricity generation was calculated by

multiplying the kilowatt-hours of electricity by 6,826 Btu/kWh (which

utilizes a thermal to electrical conversion efficiency of 50 percent). This Btu

value was then divided by the Btu value of fuel consumed in the cogeneration

boiler to determine the electricity allocation factor.

3. Thermal Output of Steam Exiting Electricity Generation: In this analysis,

the data providers stated the pounds and pressure of steam from

cogeneration. The thermal output (in Btu) of this steam was calculated from

enthalpy tables (in most cases steam ranged from 1,000 to 1,200 Btu/lb). An

efficiency of 80 percent was used for the industrial boiler to calculate the

amount of fuel used. This Btu value was then divided by the Btu value of fuel

consumed in the cogeneration boiler to determine the steam allocation

factor.


12.28.16 4004.00.002 14

LIFE CYCLE INVENTORY AND IMPACT ASSESSMENT RESULTS

This section presents baseline results for the following LCI and LCIA results for both 1,000

pounds and 1,000 kilograms of EPS resin studied:

Life cycle inventory results:

Cumulative energy demand

Non-renewable energy demand

Renewable energy demand

Total energy by fuel type

Solid waste by weight

Water consumption

Life cycle impact assessment results:

Global warming potential

Acidification potential

Eutrophication potential

Ozone depletion potential

Smog formation potential

Throughout the results sections, the tables and figures break system results out into the

following categories:

Raw and intermediate materials production

EPS resin production

ENERGY DEMAND Cumulative Energy Demand

Cumulative energy demand results include all renewable and non-renewable energy

sources used for process and transportation energy, as well as material feedstock energy.

Process energy includes direct use of fuels as well as use of fossil fuels, hydropower,

nuclear, wind, solar, and other energy sources to generate electricity used by processes.

The feedstock energy is the energy content of the resources removed from nature and used

as material feedstocks for the EPS resin (e.g., the energy content of oil and gas used as

material feedstocks).

The average total energy required to produce EPS resin is 41.8 million Btu per 1,000

pounds of resin or 96.9 GJ per 1,000 kilograms of resin. Table 2 shows total energy demand

for the life cycle of the EPS resin. The resin production has been split out from the raw and

intermediate chemicals required for the resin. Almost 94 percent of this total energy is

required to produce the raw and intermediate materials, while approximately 6 percent is

needed to produce the resin itself.


12.28.16 4004.00.002 15

Non-renewable energy demand results include the use of fossil fuels (petroleum, natural

gas, and coal) for process energy, transportation energy, and as material feedstocks (e.g., oil

and gas used as feedstocks for plastics), as well as use of uranium to generate the share of

nuclear energy in the average U.S. kWh. The main difference from cumulative energy

demand is that renewable biomass combustion energy (e.g., from combustion of wood

wastes), landfill gas used for process energy, and electricity derived from renewable energy

sources (primarily hydropower, wind, and solar) are not included in the non-renewable

energy demand results. The renewable energy demand contains those sources as

mentioned above. More than 97 percent of the total energy comes from non-renewable

sources. The main portion of the renewable energy comes from landfill gas used within the

resin production.

Table 2. Total Energy Demand for EPS Resin

Natural gas and petroleum used as raw material inputs for the production of EPS are

included in the totals for the raw and intermediate materials in Table 3. The energy from

these raw materials are called material feedstock energy. Figure 3 provides the breakdown

of the amount of total energy required for material feedstock energy versus the process

Total Energy

Non-

Renewable

Energy

Renewable

Energy

MM Btu MM Btu MM Btu

Raw and Intermediate Materials 39.1 39.0 0.092

Resin Production 2.7 1.9 0.85

41.8 40.8 0.94

Total Energy

Non-

Renewable

Energy

Renewable

Energy

MJ MJ MJ

Raw and Intermediate Materials 90,671 90,458 213

Resin Production 6,273 4,296 1,976

96,943 94,755 2,189

Total Energy

Non-

Renewable

Energy

Renewable

Energy

% % %

Raw and Intermediate Materials 93.5% 93.3% 0.2%

Resin Production 6.5% 4.4% 2.0%

100% 97.7% 2.3%Total

Basis: 1,000 pounds

Basis: 1,000 kilograms

Percentage

Total

Total


12.28.16 4004.00.002 16

and fuel energy amounts needed to produce EPS resin. As is the case for many of the plastic

resins, more than half of the total energy is associated with material feedstock.

Figure 3. Energy type for EPS Resin

Energy Demand by Fuel Type

Table 4 and Figure 4 provide the total energy demand by fuel type for the EPS resin.

Natural gas and petroleum fuels make up over 90 percent of the total energy used. As

shown in Figure 3, this is partially due to the material feedstock energy (over half of the

energy use) using those fuels to create the plastic. These material feedstock fuels are part

of the energy shown for raw materials. The resin production energy shown in table 4 and

figure 4 represents the energy required for transportation of raw materials to resin

manufacturers, the energy required to produce the resin itself, and the fuels needed to

manufacture the resin.

Petroleum-based fuels (e.g. diesel fuel) are also the dominant energy source for

transportation. Non-fossil sources, such as hydropower, nuclear and other (geothermal,

wind, etc.) shown in Table 4 are used to generate purchased electricity along with the fossil

fuels. Other renewable also includes landfill gas used for process energy in the resin

production.


12.28.16 4004.00.002 17

Table 4. Energy Demand by Fuel Type for EPS Resin

Figure 4. Energy Separated by Fuel Type for EPS Resin


12.28.16 4004.00.002 18

SOLID WASTE

Solid waste results include the following types of wastes:

Process wastes that are generated by the various processes from raw material

acquisition through production of EPS resin (e.g., sludges and residues from chemical

reactions and material processing steps)

Fuel-related wastes from the production and combustion of fuels used for process

energy and transportation energy (e.g., refinery wastes, coal combustion ash)

No postconsumer wastes of the resin are included in this analysis due to the use of a cradle-

to-resin boundary.

The process solid waste, those wastes produced directly from the cradle-to-resin

processes, includes wastes that are incinerated both for disposal and for waste-to-energy,

as well as landfilled. These categories have been provided separately where possible. Solid

wastes from fuel combustion (e.g. ash) are assumed to be landfilled.

Results for solid waste by weight are shown in Table 5 and Figure 5. The solid wastes have

been separated in to hazardous and non-hazardous waste categories, as well as by raw and

intermediate materials versus resin production. Over three-quarters of the solid wastes

come from the raw and intermediate materials. Most of the solid wastes are largely

associated with production and combustion of fuels and the production of crude oil and

natural gas used as feedstocks for the plastic resin.

Table 5. Solid Wastes for EPS Resin

Total Solid

Waste

Waste-to-

EnergyIncineration Landfill

Hazardous

Waste Total

Waste-to-


Non-

Hazardous

Waste Total

lb lb lb lb lb lb lb lb lb

Raw and Intermediate Materials 105.8 0.006 0.046 0.020 0.071 0.002 3.11 102.6 105.7

Resin Production 29.0 0.011 0.21 0.018 0.24 0 0.34 28.39 28.73

134.8 0.017 0.26 0.038 0.31 0.002 3.45 131.0 134.5

Total Solid

Waste

Waste-to-


Hazardous

Waste Total

Waste-to-


Non-

Hazardous

Waste Total

kg kg kg kg kg kg kg kg kg

Raw and Intermediate Materials 105.8 0.006 0.046 0.020 0.071 0.002 3.11 102.6 105.7

Resin Production 29.0 0.011 0.21 0.018 0.24 0 0.34 28.39 28.73

134.8 0.017 0.26 0.038 0.31 0.002 3.45 131.0 134.5

Total Solid

Waste

Waste-to-


Hazardous

Waste Total

Waste-to-


Non-

Hazardous

Waste Total

% % % % % % % % %

Raw and Intermediate Materials 78.5% 0.004% 0.034% 0.015% 0.05% 0.001% 2.31% 76.1% 78.4%

Resin Production 21.5% 0.008% 0.16% 0.013% 0.18% 0% 0.25% 21.07% 21.3%

100% 0.012% 0.19% 0.028% 0.23% 0.001% 2.56% 97.2% 99.8%

Total

Basis: 1,000 pounds

Basis: 1,000 kilograms

Percentage of Total

Non-Hazardous Wastes

Hazardous Wastes

Hazardous Wastes



Total

Total

Hazardous Wastes


12.28.16 4004.00.002 19

Solid wastes are shown separated by hazardous and non-hazardous wastes in Table 5. This

separation was done only where primary data was collected, or if a secondary data source

was clear that the solid waste was of a hazardous nature. Much of the process solid wastes

from oil and natural gas were classified as non-hazardous due to exclusions found in RCRA

hazardous wastes regulations or other EPA hazardous wastes regulations. Less than 0.3

percent of the total solid wastes were considered process hazardous wastes.

Figure 5. Solid Wastes Separated by Disposal Fate for EPS Resin

Figure 5 provides a breakout of the total solid wastes by the disposal fate. As much of the

solid wastes come from the fuel production and combustion, over 97 percent of the total

solid wastes is landfilled. Only 0.01 percent of the total solid waste is used to create energy,

while the remaining solid waste is incinerated with no energy capture.

WATER CONSUMPTION

Consumptive use of water in this study includes freshwater that is withdrawn from a water

source or watershed and not returned to that source. Consumptive water use includes

water consumed in chemical reactions, water that is incorporated into a product or waste

stream, water that becomes evaporative loss, and water that is discharged to a different

watershed or water body than the one from which it was withdrawn. Water consumption

results shown for each life cycle stage include process water consumption as well as water

consumption associated with production of the electricity and fuels used in that stage.

Electricity-related water consumption includes evaporative losses associated with thermal

generation of electricity from fossil and nuclear fuels, as well as evaporative losses due to

establishment of dams for hydropower.


12.28.16 4004.00.002 20

Water consumption results are shown in Table 6 and Figure 6. Process water consumption

dominates in the raw and intermediate material stage requiring 83 percent of the

consumed water. The extraction of natural gas and crude oil consume over 40 percent of

the water consumption for the EPS resin system, while electricity production utilizes 20

percent of the water. Resin production uses 17 percent of the total water consumed with

about 8 percent associated with the production of the resin and 7 percent associated with

generation of electricity used in the resin production.

Table 6. Water Consumption for EPS Resin

Figure 6. Water Consumption for EPS Resin

GLOBAL WARMING POTENTIAL

The primary atmospheric emissions reported in this analysis that contribute over 99% of

the total global warming potential for each system are fossil fuel-derived carbon dioxide,

Basis: 1,000

Pounds

Basis: 1,000

kilograms

Percentage of

Total

Gallons Liters %

Raw and Intermediate Materials 15,521 9,022 83%

Resin Production 3,199 1,859 17%

18,720 10,881 100%

Total Water Consumption

Total


12.28.16 4004.00.002 21

methane, and nitrous oxide. Any non-fossil carbon dioxide emissions, such as those from

the burning of wood-derived fuel, is a return of carbon dioxide to the atmosphere in the

same form as it was originally removed from the atmosphere during the biomass growth

cycle; therefore, carbon dioxide emissions from combustion or decomposition of biomass-

derived products are not considered a net contributor to global warming.

The 100-year global warming potential (GWP) factors for each of these substances as

reported in the Intergovernmental Panel on Climate Change (IPCC) 20136 are: fossil carbon

dioxide 1, fossil methane 28, and nitrous oxide 265. The GWP factor for a substance

represents the relative global warming contribution of a pound of that substance compared

to a pound of carbon dioxide. The weights of each greenhouse gas are multiplied by its

GWP factor to arrive at the total GWP results. The majority of the greenhouse gas emissions

and GWP for each system are fuel-related emissions rather than process emissions.

Table 7 and Figure 7 show life cycle GWP results for the EPS resin. Raw and intermediate

material production accounts for the largest share of GWP (90 percent), while the resin

manufacturing releases 10%. The GWP emissions from the raw material stage are mainly

associated with fossil fuel resources used as fuel and as feedstock production for the plastic

resin. Natural gas combustion releases 35 percent of the GWP emissions.

Table 7. Global Warming Potential for EPS Resin

ACIDIFICATION

Acidification assesses the potential of emissions to contribute to the formation and deposit

of acid rain on soil and water, which can cause serious harm to plant and animal life as well

as damage to infrastructure. Acidification potential modeling in TRACI incorporates the

results of an atmospheric chemistry and transport model, developed by the U.S. National

Acid Precipitation Assessment Program (NAPAP), to estimate total North American

6 IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to

the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley

(eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 2013.

Basis: 1,000

Pounds

Basis: 1,000

kilograms

Percentage of

Total

lb CO2 eq kg CO2 eq %

Raw and Intermediate Materials 2,937 2,937 90%

Resin Production 324 324 10%

3,261 3,261 100%

Global Warming Potential

Total


12.28.16 4004.00.002 22

Figure 7. Global Warming Potential for EPS Resin

terrestrial deposition due to atmospheric emissions of NOx and SO2, as a function of the

emissions location.7,8

Acidification impacts are typically dominated by fossil fuel combustion emissions,

particularly sulfur dioxide (SO2) and nitrogen oxides (NOx). Emissions from combustion of

fossil fuels, especially coal, to generate grid electricity is a significant contributor to

acidification impacts for all systems. Table 8 shows total acidification potential results for

the EPS resin. Results are shown graphically in Figure 8. Raw and intermediate material

production accounts for 84 percent of the total acidification potential, with the resin

production creating only 16 percent. Almost one-quarter of the acidification potential

comes from coal production.

Table 8. Acidification Potential for EPS Resin

7 Bare JC, Norris GA, Pennington DW, McKone T. (2003). TRACI: The Tool for the Reduction and

Assessment of Chemical and Other Environmental Impacts, Journal of Industrial Ecology, 6(34): 4978.

Available at URL: http://mitpress.mit.edu/journals/pdf/jiec_6_3_49_0.pdf. 8 Bare JC. (2002). Developing a consistent decision-making framework by using the US EPAs TRACI,

AICHE. Available at URL: http://www.epa.gov/nrmrl/std/sab/traci/aiche2002paper.pdf.

Basis: 1,000

Pounds

Basis: 1,000

kilograms

Percentage of

Total

lb SO2 eq kg SO2 eq %

Raw and Intermediate Materials 10.04 10.04 84%

Resin Production 1.91 1.91 16%

11.95 11.95 100%

Acidification Potential

Total


12.28.16 4004.00.002 23

Figure 8. Acidification Potential for EPS Resin

EUTROPHICATION

Eutrophication occurs when excess nutrients are introduced to surface water causing the

rapid growth of aquatic plants. This growth (generally referred to as an algal bloom)

reduces the amount of dissolved oxygen in the water, thus decreasing oxygen available for

other aquatic species. The TRACI characterization factors for eutrophication are the

product of a nutrient factor and a transport factor.9 The nutrient factor is based on the

amount of plant growth caused by each pollutant, while the transport factor accounts for

the probability that the pollutant will reach a body of water. Atmospheric emissions of

nitrogen oxides (NOx) as well as waterborne emissions of nitrogen, phosphorus, ammonia,

biochemical oxygen demand (BOD), and chemical oxygen demand (COD) are the main

contributors to eutrophication impacts.

Eutrophication potential results for EPS resin are shown in Table 9 and illustrated in Figure

9. Eutrophication impacts for the EPS resin are mainly from raw and intermediate material

production (82 percent), while the resin production makes up the remaining amount of 18

percent. The largest share of raw material eutrophication is from benzene production and

from the combustion of fuels in transportation.

9 Bare JC, Norris GA, Pennington DW, McKone T. (2003). TRACI: The Tool for the Reduction and

Assessment of Chemical and Other Environmental Impacts, Journal of Industrial Ecology, 6(34): 4978.

Available at URL: http://mitpress.mit.edu/journals/pdf/jiec_6_3_49_0.pdf.


12.28.16 4004.00.002 24

Table 9. Eutrophication Potential for EPS Resin

Figure 9. Eutrophication Potential for EPS Resin

OZONE DEPLETION Stratospheric ozone depletion is the reduction of the protective ozone within the

stratosphere caused by emissions of ozone-depleting substance (e.g. CFCs and halons). The

ozone depletion impact category characterizes the potential to destroy ozone based on a

chemicals reactivity and lifetime. Damage related to ozone depletion can include skin

cancer, cataracts, material damage, immune system suppression, crop damage, and other

plant and animal effects.

Table 10 shows total ODP results for EPS resin broken out by life cycle stage. The results

are shown graphically in Figure 10. Ozone depletion results for the EPS resin are

dominated by raw and intermediate material production, contributing approximately 98

Basis: 1,000

Pounds

Basis: 1,000

kilograms

Percentage of

Total

lb N eq kg N eq %

Raw and Intermediate Materials 0.31 0.31 82%


0.38 0.38 100%

Eutrophication Potential

Total


12.28.16 4004.00.002 25

percent of the total ozone depletion impacts. The raw and intermediate material ozone

depletion is primarily associated with refining the petroleum used as a resin feedstock.

Table 10. Ozone Depletion Potential for EPS Resin

Figure 10. Ozone Depletion Potential for EPS Resin

SMOG FORMATION The smog formation impact category characterizes the potential of airborne emissions to

cause photochemical smog. The creation of photochemical smog occurs when sunlight

reacts with NOx and volatile organic compounds (VOCs), resulting in tropospheric (ground-

level) ozone and particulate matter. Endpoints of such smog creation can include increased

human mortality, asthma, and deleterious effects on plant growth. Smog formation impacts,

like the other atmospheric impact indicators included in this study, are generally

dominated by emissions associated with fuel combustion, so that impacts are higher for life

Basis: 1,000

Pounds

Basis: 1,000

kilograms

Percentage of

Total

lb CFC-11

eq

kg CFC-11

eq %

Raw and Intermediate Materials 1.8E-05 1.8E-05 98%

Resin Production 4.2E-07 4.2E-07 2%

1.8E-05 1.8E-05 100%

Ozone Depletion Potential

Total


12.28.16 4004.00.002 26

cycle stages and components that have higher process fuel and transportation fuel

requirements. In this case, NOx makes up over 90% of the smog formation emissions. Smog

formation potential results for the EPS resin are shown by stage in Table 11 and illustrated

in Figure 11.

Approximately 75 percent of smog formation potential is from production of raw and

intermediate materials, while the remaining 25 percent comes from the resin production.

For the raw and intermediate material stage, 35 percent of the smog formation potential is

associated with the combustion of natural gas required for the production of various raw

and intermediate chemicals. For resin manufacturing, emissions from combustion of

transport fuels release more than half of those smog formation emissions. Electricity

production and the process energy at the EPS resin production facility each release over 15

production of the smog formation from resin production.

Table 11. Smog Formation Potential for EPS Resin

Figure 11. Smog Formation Potential for EPS Resin

Basis: 1,000

Pounds

Basis: 1,000

kilograms

Percentage of

Total

lb O3 eq kg O3 eq %

Raw and Intermediate Materials 123 123 75%


165 165 100%Total

Photochemical Smog Potential


12.28.16 4004.00.002 27

APPENDIX: EXPANDED POLYSTYRENE (EPS) MANUFACTURE

This appendix discusses the manufacture of expanded polystyrene (EPS) resin. Examples of

EPS resin end-uses include insulation, food packaging, and transport packaging.

Approximately 953 million pounds of expanded polystyrene were produced in the U.S. and

Canada in 2014 (Reference A-1). The material flow for EPS resin is shown in Figure 2 in the

Goal and Scope section. The total system process data (cradle-to-EPS) for EPS are displayed

in Table 21 at the end of this appendix. These data include all process- and fuel-related

energy or emissions for the total boundaries of the EPS resin system. Individual process

tables on the bases of 1,000 pounds and 1,000 kilograms are also shown within this

appendix. The following processes are included in this appendix:

Crude oil production

Petroleum refining (distillation, desalting, and hydrotreating)

Natural gas production

Natural gas processing

Olefin (Ethylene/Pygas) production

Benzene production

Ethylbenzene/Styrene production

Pentane production

Expanded polystyrene resin production

LCI data for all processes listed above, with the exception of pentane and EPS resin, are

currently being updated for a project for ACC Plastics Division. Updated LCI datasets for

these processes will be available by the end of 2017. Process datasets shown in this

appendix are from the current U.S. LCI Database.

CRUDE OIL PRODUCTION

Oil is produced by drilling into porous rock structures generally located several thousand

feet underground. Once an oil deposit is located, numerous holes are drilled and lined with

steel casing. Some oil is brought to the surface by natural pressure in the rock structure,

although most oil requires energy to drive pumps that lift oil to the surface. Once oil is on

the surface, it is separated from water and stored in tanks before being transported to a

refinery. In some cases, it is immediately transferred to a pipeline that transports the oil to

a larger terminal.

There are two primary sources of waste from crude oil production. The first source is the

oil field brine, or water that is extracted with the oil. The brine goes through a separator

at or near the well head in order to remove the oil from the water. These separators are

very efficient and leave minimal oil in the water.


12.28.16 4004.00.002 28

According to the American Petroleum Institute, 17.9 billion barrels of brine water were

produced from crude oil production in 1995 (Reference A-2). This equates to a ratio of 5.4

barrels of water per barrel of oil. The majority of this brine is produced by onshore oil

production facilities. Only a small percentage of onshore brine is discharged to surface

water. The majority is injected into wells specifically designed for production-related

waters (Reference A-3). The remaining brine is produced from offshore oil production

facilities, and most of this is released to the ocean (Reference A-4). Therefore, all

waterborne wastes from crude oil production are attributable to the water released from

offshore production (Reference A-5). Because crude oil is frequently produced along with

natural gas, a portion of the data is allocated to natural gas production (Reference A-2).

Evolving technologies are reducing the amount of brine that is extracted during oil

recovery and minimizing the environmental impact of discharged brine. For example,

downhole separation is a technology that separates brine from oil before bringing it to the

surface; the brine is injected into subsurface injection zones. The freeze-thaw evaporation

(FTE) process is another technology that reduces the discharge of brine water by using a

freeze crystallization process in the winter and a natural evaporation process in the

summer to extract fresh water from brine water; the fresh water can be used for

horticulture or agriculture applications (Reference A-6).

There are also waterborne emissions associated with drilling wastes. Suspensions of solids,

chemicals, and other materials in a base of water, oil, or synthetic-based material are

referred to as drilling fluids or drilling muds. These are formulated to lubricate and cool the

drill bit, carry drill cuttings from the hole to the surface, and maintain downhole

hydrostatic pressure. (Reference A-7). The volume of drilling waste is small in comparison

to oil field brine (Reference A-2). Less than 1% of drilling fluids from onshore production

are discharged to water, while about 90% of offshore drilling fluids are discharged

(References A-4, A-8). Toxic metal pollutants are released due to the use of barite, which is

employed to control the density of drilling fluids. (Reference A-7).

The primary source of atmospheric process emissions from oil extraction operations is gas

produced from oil wells. The majority of this gas is recovered for sale, but some is released

to the atmosphere. Atmospheric emissions from crude oil production are primarily

hydrocarbons, attributed to the natural gas produced from combination wells and relate to

line or transmission losses and unflared venting. Carbon dioxide is also released, primarily

from storage tank venting. The amount of methane released from crude oil production was

calculated from EPAs Inventory of U.S. Greenhouse Gas Emissions and Sinks, which has

data specific to oil field emissions (Reference A-9).

The requirements for transporting crude oil from the production field to the Gulf Coast of

the United States (where most petroleum refining in the United States occurs) were

calculated from foreign and domestic supply data, port-to-port distance data, and domestic

petroleum movement data (References A-10 and A-11). Based on 2001 foreign and

domestic supply data, 62 percent of the United States crude oil supply is from foreign

sources, 6 percent is from Alaska, and the remaining 32 percent is from the lower 48 states.

These percentages were used to apportion transportation requirements among different


12.28.16 4004.00.002 29

transportation modes. With the exception of Canada, which transports crude oil to the

United States by pipeline, foreign suppliers transport crude oil to the United States by

ocean tanker. (In 2001, Saudi Arabia, Mexico, Canada, Venezuela, and Nigeria were the top

five foreign suppliers of crude oil to the United States.) The transportation of crude oil from

Alaska to the lower 48 states is also accomplished by ocean tanker. Domestic

transportation of crude oil is accomplished by pipeline and barge.

Table 12 shows the energy requirements and emissions for the extraction of crude oil.

PETROLEUM REFINING (DISTILLATION, DESALTING, AND HYDROTREATING)

Gasoline and diesel are the primary outputs from refineries; however, other major products

include kerosene, aviation fuel, residual oil, lubricating oil, and feedstocks for the

petrochemical industry. Data specific to the production of each type of refinery product are not

available. Such data would be difficult to characterize because there are many types of

conversion processes in oil refineries that are altered depending on market demand, quality of

crude input, and other variables. Thus, the following discussion is applicable to all refinery

products.

A petroleum refinery processes crude oil into thousands of products using physical and/or

chemical processing technology. A petroleum refinery receives crude oil, which is comprised of

mixtures of many hydrocarbon compounds and uses distillation processes to separate pure

product streams. Because the crude oil is contaminated (to varying degrees) with compounds

of sulfur, nitrogen, oxygen, and metals, cleaning operations are common in all refineries. Also,

the natural hydrocarbon components that comprise crude oil are often chemically changed to

yield products for which there is higher demand. These processes, such as polymerization,

alkylation, reforming, and visbreaking, are used to convert light or heavy crude oil fractions

into intermediate weight products, which are more easily handled and used as fuels and/or

feedstocks (Reference A-22).


12.28.16 4004.00.002 30

Table 12. Data for the Extraction of Crude Oil

Total Total

Energy Usage Energy Energy

Thousand Btu GigaJoules

Energy of Material Resource

Petroleum 1,035 lb 18,770 1,035 kg 43.7

Total Resource 18,770 43.7

Process Energy

Electricity (grid) 17.7 kwh 188 39.0 kwh 0.44

Natural gas 525 cu ft 588 32.8 cu meters 1.37

Distillate oil 0.15 gal 24.6 1.29 liter 0.057

Residual oil 0.10 gal 16.4 0.80 liter 0.038

Gasoline 0.082 gal 11.7 0.68 liter 0.027

Total Process 829 1.93

Environmental Emissions

Atmospheric Emissions

Methane 5.27 lb 5.27 kg

Carbon Dioxide 1.11 lb 1.11 kg

Solid Wastes

Landfilled 26.1 lb 26.1 kg

Waterborne Wastes

2-Hexanone 1.4E-06 lb 1.4E-06 kg

4-Methyl-2-Pentanone 1.9E-07 lb 1.9E-07 kg

Acetone 4.6E-07 lb 4.6E-07 kg

Aluminum 0.021 lb 0.021 kg

Ammonia 0.0028 lb 0.0028 kg

Antimony 1.3E-05 lb 1.3E-05 kg

Arsenic, ion 4.6E-05 lb 4.6E-05 kg

Barium 0.28 lb 0.28 kg

Benzene 2.6E-04 lb 2.6E-04 kg

Benzene, 1-methyl-4-(1-methylethyl)- 4.6E-09 lb 4.6E-09 kg

Benzene, ethyl- 1.4E-05 lb 1.4E-05 kg

Benzene, pentamethyl- 3.4E-09 lb 3.4E-09 kg

Benzenes, alkylated, unspecified 4.3E-05 lb 4.3E-05 kg

Benzoic acid 2.2E-04 lb 2.2E-04 kg

Beryllium 2.9E-06 lb 2.9E-06 kg

Biphenyl, total 2.8E-06 lb 2.8E-06 kg

BOD5, Biological Oxygen Demand 0.025 lb 0.025 kg

Boron 6.9E-04 lb 6.9E-04 kg

Bromide 0.031 lb 0.031 kg

Cadmium, ion 7.1E-06 lb 7.1E-06 kg

Calcium, ion 0.50 lb 0.50 kg

Chloride 6.07 lb 6.07 kg

Chromium 5.6E-04 lb 5.6E-04 kg

Cobalt 4.9E-06 lb 4.9E-06 kg

COD, Chemical Oxygen Demand 0.042 lb 0.042 kg

Copper, ion 6.2E-05 lb 6.2E-05 kg

Cyanide 3.3E-09 lb 3.3E-09 kg

Decane 6.4E-06 lb 6.4E-06 kg

English units (Basis: 1,000 lb) SI units (Basis: 1,000 kg)


12.28.16 4004.00.002 31

Table 12. Data for the Extraction of Crude Oil (Continued)

Dibenzofuran 8.7E-09 lb 8.7E-09 kg

Dibenzothiophene 7.0E-09 lb 7.0E-09 kg

Dibenzothiophene, total 8.6E-09 lb 8.6E-09 kg

Dissolved solids 6.47 lb 6.47 kg

Docosane 4.9E-08 lb 4.9E-08 kg

Dodecane 1.2E-05 lb 1.2E-05 kg

Eicosane 3.3E-06 lb 3.3E-06 kg

Florene, 1-methyl- 5.2E-09 lb 5.2E-09 kg

Florenes, alkylated, unspecified 2.5E-06 lb 2.5E-06 kg

Fluorine 1.2E-06 lb 1.2E-06 kg

Hexadecane 1.3E-05 lb 1.3E-05 kg

Hexanoic acid 4.7E-05 lb 4.7E-05 kg

Iron 0.039 lb 0.039 kg

Lead 1.2E-04 lb 1.2E-04 kg

Lead-210/kg 2.3E-14 lb 2.3E-14 kg

Lithium, ion 1.6E-04 lb 1.6E-04 kg

Magnesium 0.10 lb 0.10 kg

Manganese 1.5E-04 lb 1.5E-04 kg

Methane, monochloro-, R-40 1.8E-09 lb 1.8E-09 kg

Methyl ethyl ketone 3.7E-09 lb 3.7E-09 kg

Molybdenum 5.1E-06 lb 5.1E-06 kg

m-Xylene 6.3E-06 lb 6.3E-06 kg

Naphthalene 4.0E-06 lb 4.0E-06 kg

Naphthalenes, alkylated, unspecified 7.0E-07 lb 7.0E-07 kg

Napthalene, 2-methyl- 3.3E-06 lb 3.3E-06 kg

n-Hexacosane 3.0E-08 lb 3.0E-08 kg

Nickel 5.4E-05 lb 5.4E-05 kg

o-Cresol 6.4E-06 lb 6.4E-06 kg

Oils, unspecified 0.0043 lb 0.0043 kg

o-xylene 2.3E-06 lb 2.3E-06 kg

p-Cresol 6.9E-06 lb 6.9E-06 kg

Phenanthrene 1.8E-07 lb 1.8E-07 kg

Phenanthrenes, alkylated, unspecified 2.9E-07 lb 2.9E-07 kg

Phenol 7.2E-05 lb 7.2E-05 kg

Phenol, 2,4-dimethyl- 6.2E-06 lb 6.2E-06 kg

p-xylene 2.3E-06 lb 2.3E-06 kg

Radium-226/kg 8.0E-12 lb 8.0E-12 kg

Radium-228/kg 4.1E-14 lb 4.1E-14 kg

Selenium 2.5E-06 lb 2.5E-06 kg

Silver 3.1E-04 lb 3.1E-04 kg

Sodium, ion 1.48 lb 1.48 kg

Strontium 0.012 lb 0.012 kg

Sulfate 0.011 lb 0.011 kg

Sulfur 5.3E-04 lb 5.3E-04 kg

Surfactants 1.2E-04 lb 1.2E-04 kg

Suspended solids, unspecified 2.32 lb 2.32 kg

Tetradecane 5.1E-06 lb 5.1E-06 kg

Thallium 2.8E-06 lb 2.8E-06 kg

Tin 5.2E-05 lb 5.2E-05 kg

Titanium, ion 2.0E-04 lb 2.0E-04 kg

Toluene 2.4E-04 lb 2.4E-04 kg

Vanadium 5.7E-06 lb 5.7E-06 kg

Xylene 1.2E-04 lb 1.2E-04 kg

Yttrium 1.5E-06 lb 1.5E-06 kg

Zinc 4.8E-04 lb 4.8E-04 kg

References: A-1, A-4, A-7, A-8, A-9, A-11, A-20, and A-21.

Source: Franklin Associates, A Division of ERG

English units (Basis: 1,000 lb) SI units (Basis: 1,000 kg)


12.28.16 4004.00.002 32

This module includes data for desalting, atmospheric distillation, vacuum distillation, and

hydrotreating. These are the most energy-intensive processes of a petroleum refinery,

representing over 95 percent of the total energy requirements of U.S. petroleum refineries

(Reference A-23). Data for cracking, reforming, and supporting processes are not available

and are not included in this module. The following figure is a simplified flow diagram of the

material flows and processes included in this module.

Air pollution is caused by various petroleum refining processes, including vacuum

distillation, catalytic cracking, thermal cracking processes, and sulfur recovery. Fugitive

emissions also contribute significantly to air emissions. Fugitive emissions include leaks

from valves, seals, flanges, and drains, as well as leaks escaping from storage tanks or

during transfer operations. The wastewater treatment plant for a refinery is also a source

of fugitive emissions (Reference A-24). Emissions of atmospheric and waterborne

emissions for petroleum refineries were derived from U.S. EPA and Department of Energy

publications (References A-21 and A-25 through A-28).

This module expresses data on the basis 1,000 pounds of general refinery product as well

as data allocated to specific refinery products. The data are allocated to specific refinery

products based on the percent by mass of each product in the refinery output. The mass

allocation method assigns energy requirements and environmental emissions equally to all

refinery products -- equal masses of different refinery products are assigned equal energy

and emissions.

Mass allocation is not the only method that can be used for assigning energy and emissions

to refinery products. Heat of combustion and economic value are two additional methods

for co-product allocation. Using heat of combustion of refinery products yields allocation

factors similar to those derived by mass allocation, demonstrating the correlation between

mass and heat of combustion. Economic allocation is complicated because market values

fluctuate with supply and demand, and market data are not available for refinery products

Atmospheric

Distillation

PETROLEUM REFINERY

Vacuum

Distillation

Desalting Hydrotreating

Simplified flow diagram for petroleum refinery operations for the production of fuels.

All arrows represent material flows. The percentages of refinery products represent percent by mass of total refinery output.

* "Other" category includes still gas, petroleum coke, asphalt, and petrochemical feedstocks .

Crude Oil

Gasoline (42.1%)

Distillate Oil / Diesel (21.9%)

LPG (2.7%)

Residual Oil (4.9%)

Kerosene / Jet Fuel (9.1%)

Other * (19.4%)


12.28.16 4004.00.002 33

such as asphalt. This module does not apply the heat of combustion or economic allocation

methods because they have no apparent advantage over mass allocation.

Co-product function expansion is yet another method for allocating environmental burdens

among refinery products. Co-product function expansion is more complex than mass, heat

of combustion, or economic allocation; it evaluates downstream processes and product

substitutes in order to determine the percentage of total energy and emissions to assign to

each refinery product. This module does not use the co-product function expansion method

because it is outside the scope of this project.

There are advantages and disadvantages for each type of allocation method. Until detailed

data are available for the material flows and individual processes within a refinery, life

cycle practitioners will have to resort to allocation methods such as those discussed above.

The energy requirements and emissions for the refining of petroleum are found in Table

13.

NATURAL GAS PRODUCTION

Natural gas is a widely used energy resource, since it is a relatively clean, efficient, and

versatile fuel. The major component of natural gas is methane (CH4). Other components of

natural gas include ethane, propane, butane, and other heavier hydrocarbons, as well as water

vapor, carbon dioxide, nitrogen, and hydrogen sulfides.

Natural gas is extracted from deep underground wells and is frequently co-produced with

crude oil. Because of its gaseous nature, natural gas flows quite freely from wells which

produce primarily natural gas, but some energy is required to pump natural gas and crude oil

mixtures to the surface. An estimated 80 percent of natural gas is extracted onshore and 20

percent is extracted offshore (Reference A-15).

Atmospheric emissions from natural gas production result primarily from unflared venting.

Methane and non-combustion carbon dioxide emissions from natural gas extraction are

generally process related, with the largest source of these emissions from normal operations,

system upsets, and routine maintenance. Waterborne wastes result from brines that occur

when natural gas is produced in combination with oil. In cases where data represent both

crude oil and natural gas extraction, the data module allocates environmental emissions based

on the percent weight of natural gas produced. The data module also apportions

environmental emissions according to the percent share of onshore and offshore extraction.

Energy data for natural gas production were calculated from fuel consumption data for the

crude oil and natural gas extraction industry (Reference A-34). The energy and emissions data

for the production of natural gas is displayed in Table 14.


12.28.16 4004.00.002 34

Table 13. Data for the Refining of Petroleum Products

Material Inputs

Crude Oil 1,018 lb 1,018 kg

Total Total

Energy Usage Energy Energy

Thousand Btu GigaJoules

Process Energy

Electricity (grid) 64.9 kwh 691 143 kwh 1.61

Natural gas 178 cu ft 199 11.1 cu meters 0.46

LPG 0.14 gal 14.9 1.15 liter 0.035

Residual oil 3.26 gal 560 27.2 liter 1.30

Total Process 1,465 3.41

Incoming Transportation Energy

Barge 0.38 ton-miles 1.23 tonne-km

Diesel 3.1E-04 gal 0.048 0.0025 liter 1.1E-04

Residual oil 0.0010 gal 0.17 0.0085 liter 4.0E-04

Ocean freighter 1,499 ton-miles 4823 tonne-km

Diesel 0.28 gal 45.2 2.38 liter 0.11

Residual 2.56 gal 440 21.4 liter 1.02

Pipeline-petroleum products 200 ton-miles 642 tonne-km

Electricity 4.35 kwh 44.5 9.59 kwh 0.10

Total Transportation 530 1.23

Environmental Emissions

Atmospheric Emissions

Ammonia 0.0036 lb 0.0036 kg

Antimony 2.0E-06 lb 2.0E-06 kg

Arsenic 2.6E-07 lb 2.6E-07 kg

Benzene 0.0011 lb 0.0011 kg

Carbon dioxide, fossil 0.25 lb 0.25 kg

Carbon monoxide 0.42 lb 0.42 kg

Chromium 6.8E-07 lb 6.8E-07 kg

Ethylene dibromide 4.3E-06 lb 4.3E-06 kg

Methane, chlorotrifluoro-, CFC-13 2.2E-05 lb 2.2E-05 kg

Methane, fossil 0.037 lb 0.037 kg

Methane, tetrachloro-, CFC-10 1.4E-06 lb 1.4E-06 kg

Nickel 5.8E-06 lb 5.8E-06 kg

Nitrogen oxides 0.42 lb 0.42 kg

0.68 lb 0.68 kg

Particulates, < 10 um 0.031 lb 0.031 kg

Particulates, < 2.5 um 0.023 lb 0.023 kg

Polycycl

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