D.2.7 B Draft of schedules for BAT and BREF in Cement ... I Sustainable Industry Low Carbon scheme...

SILC I

Sustainable Industry Low Carbon scheme

67/G/ENT/CIP/13/D/N03S02

D2.7B - Draft of schedules for BAT and

BREF in Cement, Glass, Non-ferrous

Internal document

code: D.2.7 B

Version: FINAL

Date: 31/12/2014

Status: Approved

Dissemination level: CO PP RE CO

Public

Limited to

project

stakeholders

Reserved to a

specific partner

group

Confidential,

project

partners only

V

Author: D.Forni

Project: Waste Heat Valorisation for More Sustainable Energy Intensive

IndustrieS

Acronym: WHAVES

Code: SI2.666133

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Energy Efficiency BREF

List of content:

1. Introduction 2. Analysis of the current BREF document 3. Relieved discrepancies to be revised about “COGENERATION” 4. The ORC technology

� Description � Achieved environmental benefits � Cross media effects � Operational data � Applicability � Economics � Driving force for implementation � Examples � Reference literature

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1. Introduction According to recent case studies and advance in literature and in technology, it results important to underline how the increased available choices in the field of COGENERATION and HEAT RECOVERY should lead to a review of some information included in the current version of the BREF document for “ENERGY EFFICIENCY”. Furthermore, the availability of new approaches and tools for the preliminary evaluation for selecting an effective cogeneration technology should be also remarked. 2. Analysis of the current BREF document After a carefully analysis of the BREF document: “Reference Document on Best Available Techniques for ENERGY EFFICIENCY in the BREF CEMENT” issued on February 2009, it is suggested to modify the following preliminary points:

1. HEAT RECOVERY is mentioned at point 3.3, but the associated techniques are limited to the application of Heat exchangers and Heat pumps or of Chillers and cooling systems. As a consequence this section of the BREF results not complete and up to date.

2. COGENERATION techniques are indicated in BAT n. 20 as measures for improving energy efficiency, stating that “Cogeneration opportunities should be sought on the identification of possibilities, on investment either on the generator's side or potential customer's side, identification of potential partners or by changes in economic circumstances (heat, fuel prices, etc.)”.

3. COGENERATION techniques are indicated in Chapter 3 as “Techniques to consider for achieving energy efficiency in energy-using”, at point 3.4 – Cogeneration, where only some of the applicable techniques are described. Furthermore, at point 3.4.1 some information is missing or should be more exhaustive on nowadays known and already applied techniques, such as Organic Rankine Cycle (ORC) turbogenerator.

3. Relieved discrepancies to be revised about “HEAT RECOVERY” and

“COGENERATION” In the following paragraph are presented information and data in the current BREF together with new and more detailed elements that should be considered when reviewing the BREF document. NOTE on “HEAT RECOVERY” and “COGENERATION” Neither in § 3.3 “Heat Recovery” nor in § 3.4 “Cogeneration” it is explained the role of “Heat- recovery equipment” in terms of energy efficiency. Heat-recovery equipment in CHP systems is used to capture thermal energy rejected from prime movers and other heating sources and to make the recovered heat available for useful purposes. The 2012/27/EU Directive on Energy Efficiency, in chapter III “efficiency in energy supply”, art. 5.c requires a cost benefit analysis when “an industrial installation with a total thermal input exceeding 20MW generating waste heat at a useful temperature level is planned or substantially refurbished, in order to assess the cost and benefits of utilising the waste heat to satisfy economically justified demand, including through cogeneration, and of the connection of that installation to a district heating and cooling network”.

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Anyway there was the possibility for Member States to notify exemptions and a number of Member States did it. Moreover the waste heat recovery for electricity generation is not considered cogeneration so far. Thus this measure risks not to be considered in the cost benefit analysis. NOTE: in the current BREF document the ORC systems are listed only in the COGENERATION. As a consequence, all the related notes are mainly linked to the section of the Cogeneration in the current structure of the BREF, but should be also considered in the revision of the section on heat recovery. § 3.4.1 – Cogeneration (See page 181)

a) At page 181, in Table 3.20 (List of cogeneration technologies and default power heat ratios [146, EC, 2004]) the values for some technologies are missing.

In particular, the table should be corrected as follows: - “Organic Rankin cycles” is to correct with “Organic Rankine Cycles”;

b) At page 181, after the above mentioned Table 3.20, it is stated that: “The annual load

versus time curve can be used to determine the selection and size of a CHP”. It should be added: “In case of Heat Recovery with ORC technologies, it is actually proved that other and dedicated evaluation tools can be also used. For example, the diagram reported in Figure 1 developed in the H-REII project (ref.: LIFE08 ENV/IT/000422). This tool (a.k.a. preliminary heat recovery analysis diagram) allows easily determining the needed quantities of mass flow rate (kg/s) and temperature (°C) for producing a desired amount of power (kW).”

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Temperature [°C] Potential power [kW]

Mass flow [kg/s]

Figure 1 Preliminary heat recovery analysis diagram

c) From page 182 to page 189, some different types of cogeneration power plant are described. According to the advances in terms of industrial installations, achieved benefits and economical profitability, it should be added in the BREF document also a specific sub-section on the ORC turbogenerators.

The characteristics and typical technical data of this generation technology are reported in the point “4. The ORC Technology”, where there are all the information usually present in the BREF documents (Description, Achieved environmental benefits, Cross-media effects, Operational data, Applicability, Economics, Driving force for implementation, Examples).

Example with a mass flow of 20 kg/s at 400°C can be produced 1 MW

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4. The ORC technology Description In a typical Organic Rankine Cycle (ORC) based heat recovery system, the heat contained in the waste exhaust gas is transferred indirectly -via a thermal oil circuit- or directly to the organic fluid running the Rankine cycle. The ORC plant produces electricity and low-temperature heat through a closed thermodynamic cycle which follows the principle of the Rankine cycle. In an ORC generator the organic fluid running the closed cycle (Figure 2) is pre-heated (2-7) in a regenerator, then vaporized (7-4) through heat exchange with the hot source. The generated vapour is expanded (7-5) in a turbine that drives an electricity generator. Leaving the turbine, the organic working medium (still in the vapour phase) passes through the re-generator (5-6) transferring heat to the organic liquid before vaporizing, therefore, increasing the electric efficiency through internal heat recovery. The organic vapour then condenses (6-1)) delivering heat to the cooling water circuit. After the condenser, the working medium is brought back to the pressure level required (for turbine operation) by the working fluid pump and then starts again the cycle. The low-temperature heat is normally discharged to a thermal user or to the atmosphere through air cooled radiators inserted in a closed cooling water circuit (evaporative cooling towers can also be employed). If there is a demand for low temperature heat, it is possible to design the cycle in order to condense at higher temperature and feed in to the user (e.g. heating, district heating, etc.). The operation of the ORC plant is fully automatic in normal operating conditions as well as in shut down procedures without any need of supervision personnel. In case of faulty conditions, the ORC plant will be switched off automatically and separated from the thermal oil circuit and from the electrical grid. The ORC module is designed to automatically adjust itself to the actual operating conditions: variations on exhaust gas temperatures and flows (in reasonable span times) will not affect the functionality of the system (but just the power output). When compared to alternative technologies of comparable sizes (from 0.2 to 3 MW of electric production), ORC plants demonstrate the following advantages: o Very high turbine efficiency (up to 85 %) o Low mechanical stress of the turbine, due to the low peripheral speed o Low RPM of the turbine allowing the direct drive of the electric generator without reduction gear o No erosion of blades, due to the absence of moisture in the vapour nozzles o High cycle efficiency also at partial load o Long life The technology shows many other advantages, such as simple start-stop procedures, quiet operation, minimum maintenance requirements, good performances at partial load (it is possible to operate the cycle down to 10 % of the nominal load without incurring in any problem). The ORC modules can be operated with good efficiency at partial load by simply changing the feeding conditions (thermal oil flow or temperature). The ORC plants can, without any problems, be automatically operated with values that differ from the nominal values for the thermal oil and hot water temperatures. The operation of the plant either with higher hot water outlet temperatures or lower thermal oil inlet temperatures leads to a decrease of the electric efficiency and therefore to less electricity generation of the ORC plant.

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Achieved environmental benefits

The electricity is generated using the recovered waste heat, thus without any additional consumption of fuel nor additional emissions. Moreover the electricity is usually self consumed inside the plant itself, thus avoiding also the grid losses. The avoided emissions depend on the national emissions for electricity generation. Cross-media effects Besides the lower usage of electricity and, if also heat is recovered after or before the ORC, fossil, with the related reduction of CO2 emissions, there is a consequent reduction of energy costs and. an increase of competitiveness. When the recovered waste heat feeds a district heating network, the installation of an ORC can increase the convenience of the investment, since it increases the load factor of the heat exchanger, one of the most expansive elements of the system. Operational data The operational data depend on the field of application (process), and on the size of the ORC. Usually, the technical parameters to be considered are: thermal energy waste state (fluid/gas), mass flow (kg/hour), inlet and outlet temperatures (°C), working hours (hours), type of process (steady or batch). Other parameters are important in case of refining the investigation of the achievable performances. An example of ORC technical characteristics applied in cement industry is reported in Figure 2.

Figure 2 Basis configuration of an ORC turbogenerator (left) and its representation (right)in a T-s diagram

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Figure 2 – ORC technical characteristics for heat recovery from PRS Applicability The organic Rankine cycle (ORC) turbogenerator is an effective power plant for decentralized small- to medium-scale energy applications, for an electric power output ranging, currently, from approximately 50 kWe up to about 5 MWe (Figure 3). The most relevant applications of ORC plant in industrial heat recovery are actually represented by energy intensive processes as: Steel, Cement and Glass (see examples).

Figure 3 Input temperature and output power ranges of commercially available ORC systems. (source [6]) Economics The economic viability of such systems is critically dependent on the costs of installation and maintenance costs and on the cost of electricity bought from the grid. Due to its high specific investment cost, a careful design of the ORC system is needed in order to define the best sizes of all equipment installed.

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Furthermore, the advantages of some energy intensive industrial processes (Steel, Cement, Glass) have already been studied and quantified ([4] and [5]). It is also interesting to evaluate the synergies of heat recovery for external thermal needs (district heating or other factories) and for electricity generation ([7]). Driving force for implementation

If there is no internal use of the recoverable thermal energy otherwise dispersed in the environment, the electricity generation is a viable solution to exploit this free resource. The electricity generated is usually self consumed in the plant itself lowering the electricity purchased from the grid and enhancing the energy efficiency of the plant and the profit. Examples in Europe Beyond the examples in the table below, there are a number of plants in advanced stage of construction or just commissioned around Europe. Year Sector Site ORC

Manufacturer ORC gross power [MW]

1999 Cement Heidelberg Zement, Germany Ormat 1.5 2012 Cement Holcim Romania Turboden 4 2013 Cement Jura Cement, Switzerland ABB 2 2014 Cement Holcim Slovakia Turboden 5 2011 Glass Vetrerie Sangalli Manfredonia, Italy Ormat 2.0. 2012 Glass AGC Cuneo, Italy Turboden 1.3 2013 Steel ESF Riesa, Germany Turboden 2,7 2014 Steel ABS Pozzuolo del Friuli, Italy Exergy 1,2

Reference literature

[1] D. Chinese, A. Meneghetti, G. Nardin, Diffused Introduction of Organic Rankine Cycle for Biomass-based Power Generation in an Industrial District: a Systems Analysis, Int. J. Energy Res., 28, 1003-1021, 2004.

[2] G. Angelino, M. Gaia, E. Macchi, A Review of Italian Activity in the Field of Organic Rankine Cycles, Proceedings of the Intl.VDI Seminar (Verein Deutsche Ingenieure), Bulletin 539, VDI-Düsseldorf, 465-482, 1984.

[3] S. Quoilin, V. Lemort, Technological and Economical Survey of Organic Rankine Cycle Systems , Proceedings of European Conference on Economics and Management of Energy in Industry. Vilamoura, Portugal, 2009.

[4] J. A. Moya, N. Pardo, A. Mercier , The potential for improvements in energy efficiency and CO2 emissions in the EU27 cement industry and the relationship with the capital budgeting decision criteria, Journal of Cleaner Production 19 (2011).

[5] D. Forni, N. Rossetti, V. Vaccari, M. Baresi, D. Di Santo, Heat recovery for electricity generation in Industry, Proceedings of ECEEE summer industrial study 2012.

[6] HREII project, Life EU programme http://www.hreii.eu/ [7] D. Forni, F. Campana, Innovative system for electricity generation from waste heat

recovery, Proceedings of ECEEE summer industrial study 2014.

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Cement, lime and magnesium oxide BREF List of content

1. Analysis of the current BREF document 2. Relieved discrepancies to be revised about the “COGENERATION” in the CEMENT industries § 1.2.5.8 – Cogeneration § 1.4.2.4 - Energy recovery from kilns and coolers/cogeneration § 4.2.3.2 - Cogeneration with Organic Rankine Cycle (ORC) process

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2. Analysis of the current BREF document

“Best Available Techniques (BAT) Reference Document for the Production of CEMENT,

LIME and MAGNESIUM OXIDE” Industrial Emissions Dire ctive 2010/75/EU

(Integrated Pollution Prevention and Control) (April 2013)”

After a carefully analysis of the BREF document: “Best Available Techniques (BAT)

Reference Document for the Production of CEMENT, LIME and MAGNESIUM OXIDE”

issued on April 2013, it is necessary to fix the following preliminary points:

1. the HEAT RECOVERY is mentioned in all the three industries as BAT for the

reduction of the energy consumption for thermal needs:

- for CEMENT industries, see:

§ 1.2.5.7.1.2 Planetary (or satellite) coolers

§ 1.2.5.8 Cogeneration

§ 1.4.2.4 Energy recovery from kilns and coolers/cogeneration

§ 6.2.3 Cement manufacturing – cogeneration/recovery of excess heat

see BAT n. 7, point b) and BAT n. 9 (ref.: § 4.2.3.2, pages 343-344);

- for LIME industries, see:

§ 2.2.7.6 Rotary kilns with preheaters (PRK)

see BAT n. 33, point a) (ref.: § 4.3.3, page 357);

- for MAGNESIUM OXIDE industries,

§ 3.4.3 Reduction of energy consumption (energy efficiency)

see BAT n. 56, point a) (ref.: § 4.4.2, page 370);

2. the HEAT RECOVERY techniques to be adopted are then widely described ONLY in

the CEMENT industries, while for LIME and MAGNESIUM OXIDE industries the

description is quite limited (probably, due to a not significant profitability in the costs-

benefits analysis).

- for CEMENT industries, see § 1.4.2.4, page 107;

- for LIME industries, see § 2.4.2 – Table 2.34, page 252;

- for MAGNESIUM OXIDE industries, see § 3.4.3, page 319;

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3. COGENERATION techniques are indicated in BAT n. 9 as measures for reaching the

overall reduction of the energy consumption thanks to the use of energy (thermal and

electric) recovery systems.

4. Furthermore, the reported information and the data about the use of electricity

generation processes for energy recovery in cement manufacturing need for AN

IMPORTANT REVISION. This techniques is very diffused outside Europe, adopted in

over 700 plants in China and in around 850 plants worldwide. In Europe the number of

plants with heat recovery for electricity generation based on ORC is increasing, due to

the characteristics of the European plants and to the enhanced operational performances

and the economical profitability of the ORC solution. As a consequence the application

of heat recovery for electricity generation via ORC in the cement industries needs new

and more detailed reference elements to be added in the related BREF document.

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3. Relieved discrepancies to be revised about the “COGENERATION” in the CEMENT

industries

In the following lines, the information and data in the current BREF document are

implemented or compared with the investigated new and more detailed elements that should be

mentioned in a BREF document review.

§ 1.2.5.8 – Cogeneration (See page 38)

Current version Reviewed version

“ For the first time in a German cement kiln,

the Organic Rankine Cycle (ORC) process for

the cogeneration from low temperature waste

heat has been applied.”

“The results available from the German cement

plant indicate that 1,1 MW electrical power can

be generated with the given mode of

operation.”

“Since its first application in the cement kiln of

Lengfurt (Germany), the Organic Rankine

Cycle (ORC) process for the cogeneration from

low temperature waste heat is now evaluated

and applied in various new cement plants.

Nowadays, the Organic Rankine Cycle (ORC)

turbogenerator is an effective power plant for

decentralized small- to medium-scale energy

applications, for an electric power output

ranging, from approximately 500 kWe up to

about 10 MWe.”

“The results available from the ORC

turbogenerators that started operations in

2012-2014 in the cement plants of Alesd

(Romania) 4 MWe, Wildegg (Switzerland)

2MWe and Rohožník (Slovakia) 5 MWe,

indicate that up to 5 MW electrical power can

be generated with the given mode operation.”

“Moreover the 1,5 MWe ORC turbogenerator

installed in 2010 at the cement plant of Ait Baha

(Morocco) shows the applicability and

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reliability of this solution also for warmer

climatic conditions”.

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§ 1.4.2.4 - Energy recovery from kilns and coolers/cogeneration (see page 107)

Description

The amendment proposal is:

“In general, the principle behind all the processes of combined heat and power (or

“cogeneration”) is the use of the heat otherwise dispersed by a system generating electricity only.

On the other hand, many industrial applications eject heat with characteristics not suitable for

traditional steam cycles. Steam cycles don’t allow a profitable conversion in electricity of heat in

middle-temperatures range.

In the cement industry, the diffusion of ORC turbogenerators is reflecting the increased interest in

this solution thanks to higher performances in terms of electrical power generation from low

temperature exhaust gases and lower manage and maintenance duties.”

Achieved environmental benefits

The addendum proposal is:

“the benefits from the ORC processes - in terms of CO2 emissions and reduction in the consumption of primary energy - for the EU27 cement industry have been quantified thanks to the H-REII project (H-REII project, co-financed by the Life+ programme of EU – ref.: LIFE08 ENV/IT/000422) activities, as follows:

Potential production of Electric power by ORC processes

Figure 1 Potential production of Electric power by ORC processes

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Related achieved CO2 emissions in EU27

Figure 2 Related achieved CO2 emissions

Cross media effects

No changes.

Operational data


“Nowadays, the available technologies allow increased performances of using an ORC

turbogenerator in cement manufacturing:

Ait Baha (Morocco) Plant, 2010:

heat recovery from the KILN EXHAUST GAS.

Intermediate thermal oil loop to transfer HEAT to the ORC cycle;

Condensating HEAT dissipated through intermediate water cooling loop and dry-air cooling

system.

Heat source: exhaust gas at 330°C

Gas cooled down to 220°C (extra heat used for raw material pre heating)

ORC electric power: ca. 2 MWe”

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Alesd (Romania) Plant, 2012:

heat recovery from the KILN EXHAUST GAS with intermediate thermal oil loop and from the

CLINKER COOLER AIR with a second loop of pressurised water to transfer HEAT to the ORC

cycle;

Condensating HEAT dissipated through intermediate water cooling loop and wet cooling towers.

Clinker production capacity: ≈ 4.000 ton/day

Heat source: exhaust gas @ 360°C (PRS) and 250 °C (C C)

Thermal oil (PRS) and pressurised water (CC) heat recovery loops


Rohožník (Slovakia) Plant, 2013:

Heat recovery from the KILN EXHAUST GAS with intermediate thermal oil loop and from the


cycle;




Two thermal oil heat recovery loops


Applicability

No changes.

Economics


“Nowadays, according to the increased sizes with higher performances of the current ORC

turbogenerators and to the increasing energy costs, the Business Plan in cement manufacturing

are a more attractive and profitable and can be sustainable also without incentives. The Heat

recovery with its related electric power self-production leads to an increased competitiveness due

to the lower costs of electric power used in the processes for producing the same quantities of

cement.

The exploitation of recovered heat for external use (e.g. district heating/cooling) and for electricity

generation are not necessarily alternative options, but can be synergic and can make more

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attractive the Business Plan, even if the investment is higher. This is due to the higher utilization of

the heat exchanger, one of the most costly components of the system.

Furthermore, the presence of heat recovery plants that produce power with no emission and fuel

consumption implies economic benefits also for the grid: reduction of distribution losses,

stabilization of grid load and reduction of blackouts frequency.”

Driving force for implementation

No changes.

Example plants

In the current version of the BREF, the other mentioned examples are not distinguishing between

the plants with conventional steam cycle and the ones with ORC process.

Furthermore, it results that the Lengfurt cement plant is the one and only applying an ORC

solution and that its choice seems mainly due to the funding by German government.


“there are other cement plants applying energy recovery by means of an ORC turbogenerator:

- Ait Baha in Morocco: Cement plant with installed an ORC turbogenerator, size

1.5MWe for heat recovery (started up in 2010);

- Bihor in Romania: Cement plant with installed an ORC turbogenerator, size 4MWe

for heat recovery (started up in 2012);

- Rohožník in Slovakia: Cement plant with installed an ORC turbogenerator, size

5MWe for heat recovery (started up in 2014).


See the end of next section.

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-

§ 6.2.3.2 - Cogeneration with Organic Rankine Cycle (ORC) process (see page 419)

It should be added a sub-paragraph on:

Working principle

The heat contained in the exhaust gas is transferred indirectly -via a thermal oil circuit- or directly

to the ORC plant.

The ORC plant produces electricity and low-temperature heat through a closed thermodynamic

cycle which follows the principle of the Organic Rankine Cycle (ORC).

In the ORC process, designed as a closed cycle, the organic working medium is pre-heated in a

regenerator and in a pre-heater, then vaporized through heat exchange with the hot source. The

generated vapour is expanded in a turbine that drives an electric generator. Leaving the turbine,

the organic working medium (still in the vapour phase) passes through the regenerator that is used

to pre-heat the organic liquid before vaporizing, therefore, increasing the electric efficiency

through internal heat recovery. The organic vapour then condenses and delivers heat to the

cooling water circuit. After the condenser, the working medium is brought back to the pressure

level required (for turbine operation) by the working fluid pump and then preheated by internal

heat exchange in the regenerator.

The low-temperature heat is provided to a thermal user or discharged to the atmosphere through

air cooled radiators inserted in a closed cooling water circuit (evaporative cooling towers can

also be employed).

The operation of the ORC plant is fully automatic in normal operating conditions as well as in

shut down procedures without any need of supervision personnel. In case of faulty conditions, the

ORC plant will be switched off automatically and separated from the thermal oil circuit and from

the electrical grid.

The ORC module is designed to automatically adjust itself to the actual operating conditions:

variations on exhaust gas temperatures and flows (in reasonable span times) will not affect the

functionality of the system (but just the power output).

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Description of a cement plant with ORC Based Heat recovery System

The use of an-organic fluid enables efficient use of a lower temperature thermal source stream as

exists in cement production processes, to produce electricity. The ORC operates automatically

requiring minimal supervision and maintenance, and can be configured for no water consumption.

Thermal energy contained in the two main waste heat stream – Kiln gas after pre-heating cyclones

and Clinker cooler air – is captured by waste heat oil heaters ( WHOH ), and transferred to the

ORC turbogenerator using a closed loop thermal oil sub-system ( Ref. Figure 3 ). The location of

the WHOHs depends on specific plants related factors and is defined in concert with plant

operators and referenced suppliers with the aim of:

• Not affecting the optimum cement production operation,

• Minimizing effects on existing equipment (mills, fans, filters, etc. ).

• Guaranteeing reliable and durable operations,

• Minimizing investment cost.

The ORC turbogenerator accepts the hot thermal oil generated in the WHOHs and converts

approximately 20% of the input thermal power into electric power.

The balance of this thermal power is removed from the cycle by a closed loop cooling sub-system

that typically dissipates it to the environment.

The electrical power can be delivered to the grid or used to feed the cement plant internal electric

loads.

As alternatives to thermal oil heat recovery systems, either pressurized water or saturated steam

solutions can be adopted to extract heat from the hot gas and transfer heat to the ORC plants.

As an indication, the power that can be produced by an ORC system in a typical cement making

process can range from 0.5 to 1.5 MW/ Thousand metric tons per day of Clinker production

capacity ( assuming heat recovery from Both kiln and cooler waste flows ).

Using this figure, it can be estimated that the energy produced by an ORC can account for around

10 – 20% of the total electricity consumed by a cement plant.

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Figure 3 Example of ORC based Heat Recovery System in a cement plant.

The application of ORC turbogenerators in cement plant in Ait Baha, Morocco (2010) has the

following characteristics:

Heat recovery from the KILN EXHAUST GAS.

Intermediate thermal oil loop to transfer HEAT to the ORC cycle;

Condensating HEAT dissipated through intermediate water cooling loop and dry-air cooling

system.

Heat source: exhaust gas at 330°C

Gas cooled down to 220°C (extra heat used for raw material pre heating)


The application of ORC turbogenerators in cement plant in Alesd, Romania (2012) has the




cycle;


ORC Unit

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Thermal oil (PRS) and pressurised water (CC) heat recovery loops


The application of ORC turbogenerators in cement plant in Rohožník, Slovakia (2014) has the




cycle;




Two thermal oil heat recovery loops



- VV.AA. Waste heat recovery in the cement sector: market and supplier analysis, 2014

- D. Chinese, A. Meneghetti, G. Nardin, Diffused Introduction of Organic Rankine Cycle for

Biomass-based Power Generation in an Industrial District: a Systems Analysis, Int. J. Energy

Res., 28, 1003-1021, 2004.

- G. Angelino, M. Gaia, E. Macchi, A Review of Italian Activity in the Field of Organic Rankine

Cycles, Proceedings of the Intl.VDI Seminar (Verein Deutsche Ingenieure), Bulletin 539, VDI-

Düsseldorf, 465-482, 1984.

- S. Quoilin, V. Lemort, Technological and Economical Survey of Organic Rankine Cycle

Systems , Proceedings of European Conference on Economics and Management of Energy in

Industry. Vilamoura, Portugal, 2009.

- J. A. Moya, N. Pardo, A. Mercier , The potential for improvements in energy efficiency and

CO2 emissions in the EU27 cement industry and the relationship with the capital budgeting

decision criteria, Journal of Cleaner Production 19 (2011).

- R. Vescovo, Waste heat into power, Waste heat generation August 2011.

- D. Forni, F. Campana, Innovative system for electricity generation from waste heat recovery, Proceedings of ECEEE summer industrial study 2014.

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Non ferrous metal BREF List of content

Introduction 1. Addendum proposal 2. Waste heat recovery 3 Electricity generation from waste heat 4. Organic Rankine Cycle 5. ORC-based energy recover systems

a. Heat recovery from ferro-alloys submerged arc furnaces Operational data Feasibility studies heat recovery in a silicon metal plant heat recovery in a ferro-manganese plant b. Heat recovery in the Copper Industry

Operational data Feasibility studies heat recovery in a primary copper smelter heat recovery in a copper rolling mill

Relieved discrepancies to be revised about the “COGENERATION” in the CEMENT industries § 1.2.5.8 – Cogeneration § 1.4.2.4 - Energy recovery from kilns and coolers/cogeneration § 4.2.3.2 - Cogeneration with Organic Rankine Cycle (ORC) process

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INTRODUCTION Heat recovery is present in the Final draft of Best Available Techniques (BAT) Reference Document for the Non-Ferrous Metals Industries, October 2014, in the BAT conclusions: general BAT 2c, copper BAT 22b, zinc and cadmium BAT 120a,b,c, ferro-alloys BAT 166a,b,c 167a,b 168 nickel and cobalt 181b)1, and in some cases it is also specified that the recovered heat can be used to produce electricity (copper BAT 22b, zinc and cadmium BAT 120a and ferro-alloys BAT 166a BAT 167a). In the entire document there is only one explicit reference to the Organic Rankine Cycle (in 8.3.8.1 “Recovery of heat from semi-closed furnaces”, table 8.66: Examples of heat recovery from semi-closed furnaces), within the techniques to consider in the determination of BAT for the production of ferro-alloys. In this context of high international competition, growing energy prices and rising climate change awareness, the energy efficiency and the recovery of wasted energy are a central topic, not anymore limited to the industries under IPPC and emission trading, but also within the provisions of the Energy Efficiency Directive. If there are no internal or external uses for all the recoverable waste heat, its conversion in electricity is an option that must be evaluated. The Organic Rankine Cycles (ORC) generators accept low grade heat, operate fully automatically in all working conditions with good performances also at partial loads. Those cycles are spreading for the electricity generation from waste heat recovery in various energy intensive sectors, with new plants built in the last 5 years in Iron and Steel (2 plants in Europe and 1 in Singapore), cement (3 plants in Europe and 1 in Mediterranean area) and in the float glass manufacturing (2 plants in Italy) [5]. At the moment there are no installations in the field of non-ferrous metal industries, but there are a number of feasibility studies in ferro-alloys (silicon metal, ferro-manganese, ferro-chrome) and copper (primary copper smelter and rolling mill), some at an advanced stage. Economic benefits need to be evaluated case by case, since they are related to the price of electricity and the availability of supporting schemes for waste heat recovery or innovative systems. Environmental benefits due to the lower electricity consumption have to be evaluated on country basis considering the average emission factor for electricity generation. 1. Addendum proposal

The following addendum are proposed in the sections of emerging techniques: 3.4 Emerging techniques The following techniques are emerging techniques, which means that these techniques are not fully implemented in the copper industry:

1 General BAT conclusions 14.1.2 “Energy management”, Copper 14.2.3 “Energy”, Alumina 14.3.2.1 “Energy”, Lead and tin 14.4.2 “Energy”, Hydrometallurgical zinc production 14.5.2.1.1 “Energy”, Ferro-alloys 14.7.2 “Energy”, Nickel 14.8.2 “Energy”

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Heat recovery in primary copper smelter and rolling mill for electricity generation via ORC modules with sizes ranging from hundreds of kW to various MW. 9.4 Emerging techniques The following techniques are emerging techniques, which means that these techniques are not fully implemented in the ferro-alloy industry: Heat recovery from submerged arc furnace for electricity generation via ORC modules with sizes ranging from hundreds of kW to various MW. 2. Waste heat recovery

A considerable amount of heat is wasted in many industrial plants because exhausted gases with relevant heat content are often discharged directly to the atmosphere or have to be cooled before the gas treatment. The cooling process, such as mixing exhausted gases with fresh air, spraying water in a quenching tower, etc., implies additional costs for systems, operations and maintenance. It can be both economically and environmentally convenient to exploit this otherwise dispersed heat to meet heat demands inside or outside the industry premises. If the recoverable heat does not match any internal heat demand, the transportation of heat to external users or its transformation in electricity must be evaluated (Figure 4).

wasted/dispersedheat

internalheatdemand

externalheatdemand

produc on

cycle

hea ng,

DHW,cooling

districthea ngforindustries,

building,ter aryoragriculture

Hea ng:directuse

orupgradingvia

heatpumps,

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recompression,etc.

Cooling:

absorp on,

desiccant,etc.

Hea ng–DHW:

directuseor

upgradingvia

heatpumps,etc.

Cooling:

absorp on,

desiccant,etc.

Hea ng–DHW:directuseorupgrading

viaheatpumps,etc.

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electricitygenera on

Small:S rling,ORC

Medium-large:ORC,Kalina

Large:Steamcycles

He

at

reco

ve

ry

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rarc

hy

use

s te

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olo

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Legend:

DHW:Domes cHotWater

ORC:OrganicRankineCycle

Figure 4 Waste/dispersed heat recovery opportunities and hierarchy (source HREII demo project [6]).

The exploitation of recovered heat for external use (e.g. district heating/cooling) and for

electricity generation are not necessarily alternative options, but can be synergic and can make

more attractive the Business Plan, even if the investment is higher. This is due to the higher

utilization of the heat exchanger, one of the most costly components of the system.

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3. Electricity generation from waste heat

If certain quantity and quality requirements of waste heat are met and there are no interesting internal or external uses, the heat can be exploited to generate electricity. For recovering heat quantities in the order of megawatts, a system based on a Rankine cycle is the standard solution for the electricity generation. The choice between an Organic Rankine Cycle (ORC) or a steam cycle depends on the temperature and the quantity of recoverable heat. The ORC turbogenerators are more convenient, considering investment, operational and maintenance costs, for mid and low temperature heat sources - about 250°C or, in some cases, even lower - and electrical power up to 10 MW. The ORC turbogenerators showed their reliability in the last three decades, with hundreds of applications in the geothermal and biomass sectors and are now used to exploit dispersed heat in the glass, cement and iron and steel industries.

4. Organic Rankine Cycle

An ORC turbogenerator works through sealed organic fluids, like siloxanes, hydrocarbons or refrigerant chosen in accordance of the application (see Errore. L'origine riferimento non è stata trovata., Errore. L'origine riferimento non è stata trovata. and Errore. L'origine riferimento non è stata trovata.). The thermal input for the ORC unit is typically the heat contained in the exhausted gases, which can be transferred directly to the working fluid or indirectly, through different heat carriers (thermal oil, steam, pressurized water, etc.) in an intermediate heat transfer loop. The ORC outputs are electricity and low-temperature heat, usually discharged through air-coolers. The ORC turbogenerator is based on a closed thermodynamic cycle where (Figure 5) the organic working medium is pre-heated in a regenerator (2�8), then vaporized through heat exchange with the hot source (8�3�4). The generated vapour is expanded in a turbine (4�5) that typically drives an asynchronous generator. Leaving the turbine, the organic working medium, still in the vapour phase, passes through the regenerator (5�9) to pre-heat the organic liquid before vaporizing, therefore, increasing the electric efficiency through internal heat recovery. The organic vapour then condenses (9�1), delivering heat to the cooling water circuit. After the condenser, the working medium is brought back to the pressure level required (for turbine operation) by the working fluid pump (1�2) and starts again the cycle.

Figure 5 Process diagram of an ORC turbogenerator (right) and its representation on the T-S diagram (left)

The ORC shows a high efficiency (up to 24%) for waste heat streams over 300°C. It has lower sensitivity to temperature and flow rate changes and can work at partial load down to 10% of the nominal thermal input, still with a high efficiency, thanks to the characteristics of the working fluid, guaranteeing absence of liquid at the inlet of the turbine in any load condition.

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The ORC has low operating costs, does not need water treatment or consume water. Its operation is fully automatic in normal operating conditions as well as in shut down procedures without any need of supervision personnel. In case of faulty conditions, the ORC plant will be switched off automatically and separated both from the intermediate heat transfer circuit and the electrical grid.

Description of an ORC-based heat recovery system

The use of an organic fluid enables efficient use of high and low grade thermal streams, e.g. Electric Arc Furnace exhaust, copper flash smelting furnace exhaust, re-heating furnace heat streams in rolling mills etc. The heat is typically captured by intermediate heat exchangers, like waste heat oil heaters, and transferred to the ORC turbogenerator using a closed loop heat transfer sub-system. Thermal oil heat recovery systems, pressurized water or saturated steam solutions can be adopted to extract heat from the hot gas and transfer heat to the ORC plants. The location of the heat exchangers depends on specific plants related factors and is defined concertely with plant operators and referenced suppliers with the aim of:

• Not affecting the optimum production operation;

• Minimizing effects on existing equipment (fans, filters, etc. );

• Guaranteeing reliable and durable operations;

• Minimizing investment cost.

The ORC turbogenerator accepts the hot heat carrier generated in the primary heat exchangers and converts approximately 20% of the input thermal power into electric power. The balance of this thermal power is removed from the cycle by a closed loop cooling sub-system that typically dissipates it to the environment. The electrical power can be self-consumed inside the plant or delivered to the grid.

5. ORC-based energy recover systems

a. Heat recovery from ferro-alloys submerged arc furnaces

Ferro-alloys are used in a variety of industrial sectors, like the steel and iron industries, the aluminum industry, in the chemical industry and in cement industry. Ferro-alloys are broadly divided into two big categories: bulk ferro-alloys and special ferro-alloys. In the first group are included ferro-silicon, ferro-manganese and silicomanganese, ferro-nickel and ferro-chrome. All these metals are usually produced in submerged electric arc furnaces (SAFs), which can be open, semi-closed or closed. The operation of the furnace is typically continuous. The liquid metal tapped from the furnace is then further refined and worked. The furnace off-gas are collected and then cleaned by a suitable system. At the furnace outlet, it still has high thermal energy content at mid and low temperature that can be recovered for thermal purposes or to produce electricity. For more technical and economic details about the ferro-alloy sector, we refer to Errore. L'origine riferimento non è stata trovata.. ORC-based waste heat recovery systems can be well suited to recover this waste heat and to increase the overall efficiency of the process, producing electric energy with high conversion efficiency. The environmental benefits achieved through waste heat recovery are clear. Indeed it can be roughly estimated that if the ferro-alloy producers within EU27 would have installed an

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ORC-based heat recovery system, then the avoided CO2 emissions could roughly amount to approximately 350.000 t/y.

Operational data

It is worthwhile to recall that a steam power plant of around 40 MW has been installed in the ferro-silicon plant rated around 110 MW owned by Finnfjord AS in Norway. An ORC-based waste heat recovery system that recovers the waste heat in the exhausted gas of an Electric Arc Furnace in a steelmaking shop at Riesa (Germany) will be started up at the end of 2013. The main characteristics of the ORC unit employed here are summarized below

• Production process: Steel production process (Electric Arc Furnace) rated around 70 MW;

• Primary heat source: Electric Arc Furnace exhausted gas, used to produce steam at 27 bar

and 245°C;

• ORC heat source flow rate: ~ 20 t/h;

• Electric power: ~3 MW.

Feasibility studies

Below the results of some feasibility studies for the application of ORC turbogenerators in the ferro-alloy sector are summarized.

• heat recovery in a silicon metal plant:

Production process technology: Submerged Arc Furnace rated around 35 MW; Intermediate thermal oil loop to transfer waste heat to the ORC cycle; Heat source: exhausted gas at approximately 350°C; Cooling water temperature in/out of the ORC condenser 23/31°C; ORC electric power: ~ 3,3 MW.

• heat recovery in a ferro-manganese plant

Production process technology: Submerged Arc Furnace rated around 30 MW; Intermediate thermal oil loop to transfer waste heat to the ORC cycle; Heat source: exhausted gas at approximately 400°C; Cooling water temperature in/out of the ORC condenser 30/40°C; ORC electric power: ~ 6 MW. b. Heat recovery in the Copper Industry

Copper and Copper alloys production is a very important sector within the non-ferrous metal industry. It is highly energy intensive and employs a great variety of technologies. Two production routes are possible: the primary and secondary production processes. The primary copper production process relies on various stages of refining, starting with copper-sulphidic ores to copper cathodes, which have a high purity grade (99.95 % of Cu). Roughly speaking, the process consists of: melting, converting, fire refining and electro refining. From the heat recovery point of view, the first two stages show a very high recovery potential. There is a great number of furnaces, converters and fire-refining furnaces for realization of the process. In the EU27, the most common melting furnace is the Outokumpu flash furnace. This

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furnace employs a “top-down” approach and entails blowing oxygen, air, dried copper concentrate and silica flux in a hearth furnace (see [4]). The process is continuous and is nearly auto thermal, so that small quantities of fuel are needed in order to adjust the furnace temperature. In any case a high quantity of hot SO2 rich off-gas at high temperature (over 1,000°C) is produced. The heating value of this off-gas can be recovered and used for thermal purposes (see [5]). It could be exploited to produce electricity as well. Further oxygen blown converters must be used to further refine the molten “matte”. There are two main converting processes, namely batchwise and continuous. The most popular batchwise converters in use are the Pierce-Smith converters. The process is nearly auto-thermal, so that a restrained amount of fuel is needed. Furthermore, in the process SO2-bearing off-gas is produced at high temperature, which is collected and, normally, diluted to air ([5]). The thermal energy content in this exhausted gas might be recovered to produce electricity. Secondary copper production process results from pyrometallurgic routes that are in principle similar to those of the primary copper production. However, secondary smelting stages depend strongly on the secondary material used, in particular, on its copper content, on the other constituents and the organic impurities that the scrap can contain. Hence, the number of production stages and the type of the employed furnace may vary in accordance to the secondary raw materials. The furnaces normally used in the secondary copper production plants within EU27, according to the available data, are submerged electric arc furnaces, ISASMELT furnaces and blast furnaces. The converters in use are Pierce-Smith converters and TBRC (Top Blown Rotary Converter) furnaces. Finally for fire-refining, heart-type and rotary anode furnaces are employed. The processes are analogous to those described above. The main difference consists, however, in using fuel for secondary copper production, to make up heat deficits in the furnace, while in primary copper production the process is nearly auto thermal. For further details see Errore. L'origine riferimento non è stata trovata.. With regard to the wire-rod production the following processes are interesting for heat recovery purposes. • Southwire process; • Contirod process; • Properzi & Secor process. All these processes are similar to each other with variations in the casting geometry (see Errore. L'origine riferimento non è stata trovata.). The waste heat in the exhausted gases of the furnaces used within these processes can be recovered and used to produce electric energy. Operational data

The copper producer Aurubis AG in its plant in Hamburg has installed a steam power plant that recovers waste heat, producing thereby electric energy.

Feasibility studies

Below are summarized the results of feasibility studies for the application of ORC turbogenerators in the copper sector.

• heat recovery in a primary copper smelter (melting furnace and converters):

Plant production capacity around 200,000 t/y of anode copper; Intermediate thermal oil loop to transfer waste heat to the ORC cycle;

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Heat source: exhausted gas at approximately 1200°C; Cooling water temperature in/out of the ORC condenser 25/40°C; ORC electric power: ~ 8 MW.

• heat recovery in a copper rolling mill

Plant production capacity about 250,000 t/y of copper wire-rods; Intermediate thermal oil loop to transfer waste heat to the ORC cycle; Heat source: exhausted gas between approximately 300/350°C; Cooling water temperature in/out of the ORC condenser 25/35°C ORC electric power: ~ 0,7 MW

In case of rolling mills it might be possible to adopt also direct exchange configurations, where the heat is transferred directly from the exhausted gas to the ORC working fluid. In the Iron&Steel industry NatSteel-Tata group, started in 2013 the operation of a 0,7MW ORC plant with direct exchange on the pre heating furnaces of rolling mills in Singapore. It would be interested to investigate its feasibility in the non-ferrous sector as well. Economics

Waste heat recovery with related electric power self-production leads to economic benefits and a greater competitiveness due to the lower costs of electric power used in the processes. Moreover, the presence of heat recovery plants producing electric power with no emission and no fuel consumption implies economic benefits also for the grid: reduction of distribution losses, stabilization of grid load and reduction of blackouts frequency. It is impossible to give average payback time of these systems, since the capital expenditure is site specific and on the economic savings depend on the price of the electricity.

6. Reference literature




[4] Davenport W.G., King M., Schlesinger M., Biswas A.K., Extractive metallurgy of copper, 2002 Elsevier

[5] D. Forni, F. Campana, Innovative system for electricity generation from waste heat recovery, Proceedings of ECEEE summer industrial study 2014.

[6] HREII-demo project, Life EU programme http://www.hreii.eu/demo

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Glass BREF

List of content

Introduction Amendment and addendum proposals Reference literature

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INTRODUCTION

Heat recovery is a consolidated technique in the glass sector and is present in different sections of the Best Available Techniques (BAT) Reference Document for the Manufacture of Glass, 2013. It is present in the general BAT conclusions, BAT 2vi (Use of a waste heat boiler for energy recovery), BAT 2vii (Use of batch and cullet preheating). It is also an important characteristics of a number of emerging techniques as 6.2 Advanced cullet and batch preheaters and 6.5 Submerged combustion melting technology. “Glass making is a very energy-intensive activity and the choice of energy source, heating technique and heat-recovery method are central to the design of the furnace. The same choices are also some of the most important factors affecting the environmental performance and energy efficiency of the melting operation.” (Period present in2.3 Melting techniques in 2 applied processes and techniques and in 4.8 Energy in 4 techniques to consider in the determination of BAT). The recovered heat can be directly used to preheat the combustion air (in regenerative or recuperative furnaces) and/or directly or indirectly preheat batch and cullet. Moreover depending on the process and on the boundary conditions it can also be advantageous to recover heat from waste gases for internal uses as heating/cooling, heating of liquid fuels, electricity or mechanical power generation or for external industrial heat/steam demand or for feeding a district heating/cooling network. In the current context of high international competition, growing energy prices and rising climate change awareness, the energy efficiency and the recovery of wasted energy are a central topic, not anymore limited to the industries under IPPC and emission trading, but also within the provisions of the Energy Efficiency Directive. If there are no internal or external uses for all the recoverable waste heat, its conversion in electricity is an option that must be evaluated. The Organic Rankine Cycles (ORC) generators accept low grade heat, operate fully automatically in all working conditions with good performances also at partial loads. Those cycles are spreading for the electricity generation from waste heat recovery in various energy intensive sectors, with new plants built in the last 5 years in the float glass manufacturing (2 plants in Italy), in cement (3 plants in Europe and 1 in Mediterranean area) and Iron and Steel (2 plants in Europe and 1 in Singapore) [6]. Moreover the exploitation of recovered heat for external use (e.g. district heating/cooling) and for electricity generation are not necessarily alternative options, but can be synergic and can make more attractive the Business Plan, even if the investment is higher. This is due to the higher utilization of the heat exchanger, one of the most costly components of the system [6]. In Europe, in the around 60 plants producing flat glass has been evaluated that it is theoretically possible to install around 80 MW of electric generation power and generate around 470 GWh/year [5]

Range Capacity ORC Power

No. Plants Total ORC Electricity

production

[t/day] [kW] power [MW] [GWh]

<400 350 1 040 1 1 6

400-550 475 1 040 22 23 138

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550-700 625 1 500 28 42 252

>700 750 1 800 7 13 78

Total 58 79 474

Table 1 Evaluation of the potential of ORC installations in the EU27 flat glass industry [5]. The application of ORC turbogenerators to waste heat recovery for electricity generation is not limited to the float glass sector. For instance in the hollow glass there are several feasibility studies for the recovery systems for the generation of electricity. The information in the BREF regarding the electricity generation from waste heat recovery should be revised, considering the additional energy recovery opportunities ORC can offer for smaller plants, lower temperature heat or in combination with district heating/cooling and the performance and profitability demonstrated in the installations in the glass sector. 1. Amendment and addendum proposals

The following parts of the Best Available Techniques (BAT) Reference Document for the Manufacture of Glass, 2013 should be amended to take into consideration the new data from installation and the advancement of techniques. 3.4.5 (Flat glass) Energy (page 121)

Current version Reviewed version “A limited number of furnaces are equipped with turbines and generators to produce electricity from steam.”

“A limited number of furnaces are equipped with turbines and generators to produce electricity from steam. Considering the ORC turbogenerators the situation is different: in Italy recently two plants installed ORC turbogenerators and other feasibility studies are on-going”

In 4.8.4 Waste heat boiler (page 316)

Current version Reviewed version “The principle of this technique is to pass waste gases directly through an appropriate tube boiler to generate steam. The steam may be used for heating purposes (space heating and heating of fuel oil storage and piping) or, via a suitable steam motor or turbine to drive electricity generation equipment or plant items such as air compressors or Individual Section (IS) machine ventilator fans.”

“The principle of this technique is to pass waste gases directly through an appropriate tube boiler to generate steam. The steam may be used for heating purposes (space heating and heating of fuel oil storage and piping) or, via a suitable steam or ORC mover drive electricity generation equipment or plant items such as air compressors or Individual Section (IS) machine ventilator fans. Moreover the heat exiting the steam or ORC cycle can be further exploited if there is a demand for low temperature heat (e.g. space or district heating/cooling). The synergies of waste heat recovery use for electricity or mechanical force generation and district

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“In many cases, the quantity of recoverable energy is low for efficient power generation and supplementary firing may be needed to generate superheated steam to drive turbines.” “Recuperative furnaces with higher waste gas temperatures or installations where it is possible to group the waste gases from several furnaces offer more opportunities for power generation.”.

heating/cooling should be carefully evaluated. These two uses are not necessarily alternative, but can also enhance the profitability of the installation, since there is a higher exploitation of the heat recovery, one of the most capital intensive part of the system.” “In many cases, the quantity of recoverable energy is low for efficient power generation with steam turbines. In these cases, instead of supplementary firing to drive a steam turbine, the ORC generators can be a solution, with electric output powers starting from 50 kW up to several MW. This solution is also suitable to recover heat at lower temperatures (<300°C) and work seamlessly at partial load.” “Recuperative furnaces with higher waste gas temperatures or installations where it is possible to group the waste gases from several furnaces offer more opportunities for power generation. In case of smaller furnaces should also be evaluated the use of ORC generators, with electric output powers starting from 50 kW up to several MW”.

Moreover we suggest to introduce a chapter describing the different available options for waste heat recovery or at least a table summarizing the main technical and economic figures of the different options (i.e. steam generation, electricity conversion with steam turbine or ORC, etc.), as Table 8.66: Examples of heat recovery from semi-closed furnaces in the BREF of Non-Ferrous Metals Table 8.66: Examples of heat recovery from semi-closed furnaces

Technology Waste heat medium

Heat recovered as

Temperature range of waste heat (°C)

Yield (%) m EUR/MWh

Waste gas/cooling water/hot oil

Hot water 50 – 200 75 – 95 0.4 – 2

Heat pump Water /exhaust air

Hot water (temp. 50 – 90 °C)

25 – 60 COP: 3 – 5 30 – 50

Shell boiler, water-based

Waste gas

Saturated steam 6 – 15 bar; Temp. 160 – 200 °C

200 – 600 30 – 65 25 – 50

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Water tube boiler, water- based

Waste gas

Superheated steam 8 – 60 bar; Temp. 280 –480 °C

400 – 1000 30 – 75 40 – 150

Boiler ORC/turbine

Waste gas Electricity 150 – 500 10 – 15 70 – 120

Water boiler/turbine

Waste gas Electricity 500 – 1000 20 – 35 300 – 400

Thermoelectric panel

Electricity Heat radiation 800 – 1500

5 – 10

COP: Coefficient of performance. ORC: Organic Rankine cycle.

Source: Subgroup 2012

The reference to the following plants should be added Sangalli, Manfredonia (Italy) Heat recovery operation started in 2011 Heat recovery from the exhaust gases of the recuperative furnace Heat exchangers before and after the gas treatment unit Intermediate thermal oil loop between heat exchangers and ORC Glass production capacity: ≈ 600 ton/day ORC electric power: ca. 1.3 MWe AGC, Cuneo (Italy) Heat recovery operation started in 2012 Heat recovery from the exhaust gases of the recuperative furnace Heat exchanger before the gas treatment unit Intermediate thermal oil loop between heat exchangers and ORC Glass production capacity: ≈ 600 ton/day ORC electric power: ca. 2 MWe

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[4] D. Forni, Waste heat recovery expertise, Glass Worldwide 48 2013 [5] HREII-demo project, Life EU programme http://www.hreii.eu/demo [6] D. Forni, F. Campana, Innovative system for electricity generation from waste heat

recovery, Proceedings of ECEEE summer industrial study 2014. [7] AA. VV. Best Available Techniques (BAT) Reference Document for the Non-Ferrous

Metals Industries, final draft, October 2014

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