Diesel Exhaust

Raghupatruni 1 Design and Selection of Exhaust Heat Recovery Application

Experimental Study of Heat Recovery

from Diesel Exhaust at UAF

Prasada Rao Raghupatruni, Chuen–Sen Lin, Dennis Witmer

Ed Bargar, Jack Schmid, Thomas Johnson

University of Alaska Fairbanks


Overview

Introduction

Objectives

Background

Heat recovery system design consideration

Exhaust heat recovery system

Hardware and instrumentation

Experimental procedure

Results

Conclusions

Acknowledgements


Introduction

Alaskan villages consums about 374,000 MWh electric energy (about 40% of the total fuel energy) annually from diesel generators.

There are unused energy from the engine. Example: 30% of the total fuel energy (about 285,000 MWh) dissipates into the atmosphere from exhaust as heat.

1 gallon diesel contains about 130,000 Btu (0.0381 MWh) of energy

To recover the engine heat for useful applications may save lots of energy or fuel.

Rising cost of diesel fuel may become the driving force for heat recovery

Soot, corrosivity and cost are the major obstacles to heat recovery

Cleaner fuels and cleaner engines might help reduce the obstacles

Exhaust 30%

Power 38%

Liquid jacket

water 18%

Friction

Radiation

7%

Air After

Cooler

7%


Objectives

Select the most beneficial application to recover heat from diesel engine exhaust

Design a heat recovery system – economic, reliable, efficient

Conduct feasibility, performance and economic analysis


Sulfur naturally present in crude oil

Sulfur in conventional diesel = 350ppm

SO2 : Dissolve in free moisture to form sulfrous acid H2SO3

1 to 2% of SO2 is further oxidized into SO3

SO3 : Combined water vapor to form sulfric H2SO4

Acid dew point (Depends on amount of excess air in combustion, moisture

content, amount of sulfur in fuel)

2010 diesel with 15ppm sulfur content (ULSD) (Acid dew point dropped)

EPA tier 4 standards to off road engines by 2011

This may make heat recovery from diesel engines exhaust easier as there is less

acid and PM in the exhaust

Background about obstacles


Soot formation

Major pollutants – NOx and (particulate matter) PM

PM results from un burnt HC and effects health and visibility

The composition of particulate matter by mass are:

Metal – 1.2%, Hydrogen – 2.6%, Nitrogen – 0.5%, Oxygen – 4.9%

Sulfur – 2.5%, Carbon – 88%

Accumulation of PM is referred to as soot

Background about obstacles


Experimental Gas-side Pressure Drop and Fouling Resistance for a Fined Tube Bundle in a Diesel Engine Exhaust

*W. J. Marner, “Compact Heat Exchanger”

Some important parameters: temperature and velocity



Selection of recovery application

Space and community water loop heating

Desalination

Heat for refrigeration and air conditioning

Heat to power conversion

Thermal electric conversion

Experimental site

Detroit Diesel engine-generator set located at Energy Center, UAF Excellent laboratory site for potential heat recovery application

• Adjust and control engine loads

• Data acquisition system



Design requirements

Apply existing technology

Optimize overall efficiency for varying engine load (25 to 100%)

Minimize corrosion to exhaust system and heat recovery system

Meet back pressure requirement (13.8 kPa or 2 psi)

Meet dimension constraints (very limited space)

Be able to emulate different heating applications of Alaskan villages

Be able to measure system and component performance

Be easy to maintain and do not increase maintenance frequency

Work under a wide range of ambient temperatures (-40oC to 33oC)

Be reliable



Heat exchanger selected for full load

Unit heater dump load and temperature control for load simulation

Pressure drop and pump selection

Data acquisition system• Mass flow and delta T

of both exhaust and coolant loops

• Pressures• Fuel flow rates• Engine and heating

loads

Gas/liquid Inlet

temperature

Outlet

temperature

Exhaust 540 0C

(1004 0F)

177 0C

(350 0F)

Coolant 77 0C

(170 0F)

88 0C

(190 0F)

Heat recovery system design


Pipeline was designed to fit the ISO container design

Physical dimensions of heat exchanger was 51”x 18” x 23”

The heat exchanger was installed on top of the ISO container

• Convenience

• Hot gases prefer to rise

The size of the unit heater and the improved efficiency of the use of cold ambient air required it to be installed outside ISO container

Pipe and control section was installed inside the ISO container.

The temperature inside the ISO container was maintained above freezing

Hardware and instrumentation


Heat recovery system

1

2

3

45

Heat source section

Heat exchanger (1) and Related components

Heat sink section

Unit heater (2), 3-way valve (3) by pass line, and related components

Pipe and control section

Pump (4), flow meter (5), and related components


Heat Exchanger

Quotation 1 Quotation 2

Shell side Gas Liquid

Tube side Liquid Gas

Gas pressure drop

0.31 psi 2 psi

Maintenance Removable core, 1” gap

and straight tubesU-tube for gas

Heat transfer area

87 ft2 30 ft2

Size 51”x28”x28” (with detailed

drawings)

Shell Φ6.625”, Tube:72”

(No details)

Weight 725 lbs 350 lbs

Material of construction

Tube- SS fin tubeShell- SS inner wall

Tube: Plain SS 316Shell: CS

Insulation Integrated insulation No insulation included

Cost ($) 9,800 7,979


Hardware and Instrumentation

Inlet

Outlet

Drain

Bronze ball

valve

Pressure

gauge

Air ventRelease

valve

Temperature

sensor

Bronze ball

valve


Space allocation




Circuit

setter

Strainer

From

unit

heater

To unit

heater

Expansion

tank

Circuit

setter

Strainer

From

unit

heater

To unit

heater

Expansion

tank



Unit heater

To Unit Heater

From Unit Heater

3 way valve

Temperature

thermocouple Insulation

3 way valve

Temperature

thermocouple Insulation

By pass line


Hardware and Instrumentation (UAF)C o m p o n e n t Q t y U n i t P r ic e T o t a l P r ic e

T r i s ta n d p ip e v i s e 1 $ 3 1 9 .0 0 $ 3 1 9 .0 0

B o x b e a m 3 " X 3 " X 1 /8 " 2 0 f o o t b a r 1 $ 7 5 .5 7 $ 7 5 .5 7

F la t s to c k 3 " X 3 /1 6 " 2 0 f o o t b a r 1 $ 2 4 .3 1 $ 2 4 .3 1

A n g le b a r 2 - 1 /2 " X 2 - 1 /2 " X 3 /1 6 " 2 0 f o o t b a r 1 $ 3 3 .2 2 $ 3 3 .2 2

F la t s to c k 1 - 1 /2 " X 1 /8 " 2 0 f o o t b a r 1 $ 9 .5 0 $ 9 .5 0

F la t s to c k 1 " X 1 /8 " 2 0 f o o t b a r 1 $ 6 .5 7 $ 6 .5 7

B o x b e a m 1 - 1 /2 " X 3 " X 1 /8 " 2 0 f o o t b a r 2 $ 5 6 .5 4 $ 1 1 3 .0 8

B o x b e a m 1 - 1 /4 " X 1 - 1 /4 " X 1 /8 " 2 0 f o o t b a r 2 $ 3 2 .0 2 $ 6 4 .0 4

B o x b e a m 2 " X 2 " X 1 /4 " 2 0 fo o t b a r 1 $ 8 7 .2 3 $ 8 7 .2 3

F le x ib l e , i n s u l a te d t h e r m o c o u p l e p r o b e s w i t h e x p o s e d 1 5 $ 1 7 .5 0 $ 2 6 2 .5 0

S l ip o n F l a n g e , 1 5 0 p s i , 5 " p i p e d ia , 1 0 " O D , 8 - 1 /2 " b o lt 3 $ 3 8 .0 3 $ 1 1 4 .0 9

G r e a t s tu f f i n s u la t i n g fo a m s e a l a n t 6 $ 8 .4 9 $ 5 0 .9 4

C e n t r i f u g a l P u m p 1 /3 H P 3 0 G P M 1 $ 6 7 2 .0 0 $ 6 7 2 .0 0

E x p a n s io n t a n k 1 $ 3 4 .1 8 $ 3 4 .1 8

H e a t E x c h a n g e r 1 $ 1 0 ,0 1 9 $ 1 0 ,0 1 9 .0 0

F ib e r g l a s s in s u la t io n - b a g 1 $ 6 1 .7 9 $ 6 1 .7 9

S i g n a l C o n d it io n e r 0 - 5 V 1 $ 5 2 4 .0 0 $ 5 2 4 .0 0

T u r b in e f l o w m e te r , 4 - 6 0 l i n e a r r a n g e ( G P M ) 1 $ 1 ,2 8 9 $ 1 ,2 8 9 .0 0

P r e s s u r e g a u g e , d c p o w e r e d , d u a l a la r m s 3 $ 3 7 5 .0 0 $ 1 ,1 2 5 .0 0

T y p e K g r o u n d e d th e r m o c o u p le p r o b e w i t h 1 0 $ 2 5 .9 0 $ 2 5 9 .0 0

T y p e K u n - g r o u n d e d th e r m o c o u p le p r o b e w i t h 2 5 $ 2 6 .8 0 $ 6 7 0 .0 0

T y p e K u n - g r o u n d e d th e r m o c o u p le p r o b e w i t h 1 0 $ 2 7 .6 0 $ 2 7 6 .0 0

T e f lo n in s u la te d t y p e K th e r m o c o u p le w i r e 1 $ 4 0 5 $ 4 0 5 .0 0

M in ia tu r e t y p e K t h e r m o c o u p le c o n n e c to r p a i r 5 0 $ 4 $ 2 0 0 .0 0

T y p e K g r o u n d e d th e r m o c o u p le p r o b e w i t h 1 0 $ 2 4 $ 2 4 0 .0 0

T y p e K g r o u n d e d th e r m o c o u p le p r o b e w i t h 1 0 $ 2 4 $ 2 4 0 .0 0

2 4 g a u g e g a l v a n i z e d m e ta l ( S iz e 6 3 " X 3 9 " ) 1 $ 7 8 .0 0 $ 7 8 .0 0

2 4 g a u g e g a l v a n i z e d m e ta l ( S iz e 6 0 " X 4 0 " ) 2 $ 7 8 .0 0 $ 1 5 6 .0 0

2 4 g a u g e g a l v a n i z e d m e ta l ( S iz e 6 6 " X 4 2 " ) 1 $ 1 0 0 .0 0 $ 1 0 0 .0 0

S i n g le lo o p c o n tr o l l e r w i t h tw o 0 - 1 0 V D C a n a l o g o u tp u t s 1 $ 1 0 0 .4 5 $ 1 0 0 .4 5

1 - 1 /4 i n c h 3 W B R c o n t r o l v a lv e U F x U F w i t h 0 -1 0 V D C 1 $ 2 9 2 .7 7 $ 2 9 2 .7 7

N ic k e l im m e r s io n t e m p e r a tu r e s e n s o r 1 $ 3 5 .0 2 $ 3 5 .0 2

3 0 V A t r a n s fo r m e r f o r R W D c o n tr o l l e r 1 $ 2 1 .6 4 $ 2 1 .6 4

H y d r o n i c u n i t h e a te r , m o d e l S - U n i t h e a te r 1 $ 1 ,6 5 5 $ 1 ,6 5 5 .0 0

P i p e c o m p o n e n ts $ 6 ,3 0 3 .9 0

M is c e l l a n e o u s f r o m w a r e h o u s e $ 4 ,0 0 0 .0 0

T o t a l c o s t $ 2 9 ,9 1 7 . 8 0


Hardware and Instrumentation (Field)

Component Qty Unit Price Total Price

Box beam 3"X3"X1/8" 20 foot bar 1 75.57$ 75.57$

Flat stock 3"X3/16" 20 foot bar 1 24.31$ 24.31$

Angle bar 2-1/2"X2-1/2"X3/16" 20 foot bar 1 33.22$ 33.22$

Flat stock 1-1/2"X1/8" 20 foot bar 1 9.50$ 9.50$

Flat stock 1"X1/8" 20 foot bar 1 6.57$ 6.57$

Box beam 1-1/2"X3"X1/8" 20 foot bar 2 56.54$ 113.08$

Box beam 1-1/4"X1-1/4"X1/8" 20 foot bar 2 32.02$ 64.04$

Box beam 2"X2"X1/4" 20 foot bar 1 87.23$ 87.23$

Slip on Flange, 150 psi, 5" pipe dia, 10" OD, 8-1/2" bolt 2 38.03$ 76.06$

Great stuff insulating foam sealant 6 8.49$ 50.94$

Centrifugal Pump 1/3HP 30GPM 1 $672.00 672.00$

Expansion tank 1 34.18$ 34.18$

Heat Exchanger 1 $10,019 10,019.00$

Fiberglass insulation - bag 1 61.79$ 61.79$

Type K un-grounded thermocouple probe with 6 $26.80 160.80$

teflon insulated type K thermocouple wire 1 $405 405.00$

miniature type K thermocouple connector pair 50 $4 200.00$

Pressure gauge 3 $10 30.00$

24 gauge galvanized metal (Size 66"X42") 1 100.00$ 100.00$

Single loop controller with two 0-10VDC analog outputs 1 100.45$ 100.45$

1-1/4inch 3W BR control valve UFxUF with 0-10VDC 1 292.77$ 292.77$

Nickel immersion temperature sensor 1 35.02$ 35.02$

30VA transformer for RWD controller 1 21.64$ 21.64$

Pipe components $6,303.90

Labor cost 80 75.00$ 6,000.00$

Parts 1 400.00$ 400.00$

Total cost 24,977.07$


Experimental Plan

Verify performance of system—as compared to design

• Measure heat flows

Evaluate maintainability

• Soot formation

• Corrosion

Economic analysis

Purpose


Experimental Plan

Heat recovery system - operated and monitored for nearly 350 hours

Hour Coolant Purpose

0 to 150 Water Investigation of the performance of system and components (e.g.

leakages, inappropriate calibrations)

Investigation of the effect of the heat recovery system on engine

performance

150 to

250

40%

Propylene

glycol

Investigate performance consistency

250 to

350

40%

Propylene

glycol

Collection of data for performance and economic analysis

Engine load: 25%, 50%, 75%, and 100%

Heat exchanger outlet temperature: 88 oC, 77 oC, 65 oC

Test procedure

This presentation reports the performance results for 100% engine load and 87 oC.


Results

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

0 25 50 75 100

% Load

Flo

w (

Kg/

s)Total fluid flow rate (Kg/s) Flow rate in bypass (Kg/s) Flow rate across Radiator (Kg/s)

Fluid flow distribution across the bypass and unit heater-different loads


Results

0

10

20

30

40

50

60

70

0 10 20 30 40 50

Time (hrs)

Heat

ab

so

rb

ed

or h

eat

dessip

ate

d (

KW

)

.

-35

-30

-25

-20

-15

-10

-5

0

Time (hrs)

Tem

peratu

re (

deg

C)

.

Heat absorption by Propylene (KW) Dissipated heat from unit heater (KW) Total pipe heat loss (KW) Ambient temperature (deg C)


Results

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50

Time (hrs)

Hea

t re

leas

e o

r h

eat ab

sorb

ed (

KW

)

Heat release by exhaust (KW) Heat absorption by propylene (KW)


Soot Deposition Results

Collected and measured -150 grams of soot

Cleaning: Compressed air and/or a soft brush

Estimated maintenance – Not more than twice a year

No trace of any corrosion spot was observed


Economic Results

Initial cost of the recovery system = $30,000 (UAF system)

Installation cost = $6,000 ($75/hr x 8hours x 10 days)

Airfare, lodging, meals = $1,950 ($600 Airfair + $90/day x 15 days)

Total capital cost = $37,950

Maintenance cost:

$2400 per year

$1200 per visit: One day of labor ($75/hr) and flight ticket ($600)

$300 for supplies

Heat recovered per hour = 204,728 Btu

Heating value of fuel = 130,000 Btu/gal

Assuming 100% recovered heat used and 60 kW heat recovery

rate at rated load with 8 hours per day


Economic Results

Payback time with fixed capital cost

0

1

2

3

4

5

6

7

8

1.5 2 2.5 3 3.5 4

Fuel price /gal ($)

Pay

bac

k t

ime

(yrs

) .

0% 5% 10% 15%


Conclusions

The performance of our exhaust heat exchanger was reliable and consistent.

For the 125 kW diesel generator used in this experiment, the rate of heat recovered from

the exhaust was about 60 kW.

No effects were observed on the engine performance and maintenance frequency due to

the heat recovery system.

According to the soot accumulation data obtained from this experiment, the estimated time

for heat exchanger maintenance is less than two days per year.

Corrosion was not observed to be a problem in the laboratory test of 350 hours.

Based on experimental data obtained from this experiment, the estimated payback time for

a 100% and 8 hours/day use of recovered heat would be about 3 years for a fuel price of

$2.5 per gallon. For 80% use of the recovered heat, the payback time would be 4 years.

Operation cost is largely case dependent. Influential parameters would include diesel fuel

cost, the application of the recovered heat, location of the power plant, etc.

Performance and economic outcomes will be different from one case to another. However,

analysis is recommended before the installation of an exhaust heat recovery system to a

village generator set.


Acknowledgements

DOE

ICRC

AVEC


Questions ???


Vendors

Cain Industries Inc.

Tel: 262-251-0051 Ext-19

800-558-8690

cainind.com

ITT Heat Transfer

175 Standard Parkway

Cheektowaga, NY

716-862-4058



y = 1.058x - 0.0931

R2 = 0.9992

1.00

1.05

1.10

1.15

1.20

1.25

1.30

1.35

1.40

1.45

1.50

0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50 1.60

Load cell (kg/s)

DA

Q (

kg/s

)

Net weight(kg/s) Linear (Net weight(kg/s))

Flow meter calibration curve


Tier 3 and Tier 4 General Information (Off-Road)

Tier 3 (grams/kilowatt-hour): Non-Methane Hydrocarbons+NOx (NMHC+NOx): 4.0

Carbon Monoxide (CO): 3.5Particulate Matter (PM): 0.2Approximately: 2008 to 2010

Tier 4 (grams/kilowatt-hour):Non-Methane Hydrocarbons (NMHC): 0.19

Oxides of Nitrogen (NOx): 3.5Carbon Monoxide (CO): 0.4Particulate Matter (PM): 0.02Approximately: 2011

ULSD: 2010Solutions:

Fuel: Synthetic diesel, ultra low sulfur diesel (ULSD)After treatment

Diesel Exhaust

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