13-04-20231

EXPERIENCES WITH AN ORC TO INCREASE THE ENERGY EFFICIENCY IN

A MUNICIPAL WASTE INCINERATOR

Jeroen Vanwalleghem

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Summary

The waste incinerator of MIROM. Extension of the heat recovery with electricity. The organic rankine cycle. Application in MIROM Roeselare. Some data, graphs and results. Calculation of expenses. Conclusion and future.

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MIROM Roeselare

Is a union of 15 municipalities established for collecting and treating municipal waste. The region counts 270.000 inhabitants.

The waste is collected separately: residual waste, paper, PMD (plastic and metal cans, bricks).

20 recycling parks. Own waste incinerator – only residual waste.

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The waste incinerator of MIROM

Two lines, each with a furnace, boiler, ESP, dry gascleaning with injection of bicar and active coal. Baghouse with Remedia catalytic filters and a shell denox system.

2 * 4 ton/h or 62.000 ton/year. Boilers with superheated water of 180°C.

2 * 7 MW or 115.000 MWh/y. Since 2010 extra Economizers: 2 * 0,75 MW

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18MW-180°C

110°C1986

180°C

3,1MWe

2008

1976

Gas : 7MW

2004

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Heat recovery

Primary circuit of 180 °C, pression 15 bar and heat exchanger.

Town heating system of 110 °C, 5 bar. 21 customers with a heat demand around 25.000

MWh. 5.000 MWh for preheating of combustion air. Expansion of the distance heating is not possible.

Forced to look for other systems to increase energy recovery.

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District heating

8

• Circuit to city centre: 4,5 km(x2)

• Circuit to greenhouses: 2,5 km(x2)

• 21 customers

MIROM

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Choice for electricity

MIROM did not find other customers who needed lots of energy.

Production of electricity was the only option. Primary temperature of 180 °C is far too low

to make electricity with steam.

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Why did MIROM choose an ORC

Boilers are still in perfect condition. The town heating system stays primary, so

energy to ORC will fluctuate. ORC is easily adjustable. Organic fluid evaporates at low temperature.

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Property of solkatherm

Looks like water, smells like solvent. Heavier than water: 1,36 kg/l. Boils at 35,6 °C. Not toxic. Not explosive or flammable. Self-ignition temp.: 580 °C.

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Some data

Installed: input = 17 MWth, output = 3,1MWe. Design conditions: input 15 MW, T amb. 15°C

gives output 2,4 MWe. Average efficiency: 15,6%. Range: 2.900 kW – 100 kW.

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Investment in EUR

ORC: 5.300.000Heat connection: 725.000Building: 900.000

Total: 6.925.000

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Heat recovery in 2011 in MWh

Produc-tion

boilersMWhth

Town heating

MWhth

PreheatPrim.

AirMWhth

Energy to ORC

MWhth

Produ-ced

electr.Mwhe

Total Recov.

MWh

142.525 24.100 5.200 107.000 16.930 46.230

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Production of electricity

See next slide. ORC runs since july 2008. Even in winter there is still production.

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Energy balance '08 - '09 Electricity - BOUGHT [MWh] Electricity - SOLD [MWh]

Total Electricity Production [MWh] Own consumption [MWh]MWh/month

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Balans elektriciteit 2011Aankoop - Totaal 195 MWh

Verkoop - Totaal 8814 MWh

Productie - Totaal 16930 MWh

Eigen verbruik - Totaal 8325 MWhMWh/maand

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Power '08 - '09Electricity - BOUGHT [kW]

Electricity - SOLD [kW]

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Vermogens 2011

Gemiddelde Injectie actief vermogen

Gemiddelde Afname actief vermogen

Gemiddeld opgewekt vermogen ORC

Eigen verbruik

kW

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Efficiency

ORC follows thermal load between full range Guaranteed average gross efficiency =

15,6% Gross efficiency varies between 15% and

17% depending on outside temperature conditions and thermal load

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Reliability - Availability

Total amount of running hours during 2011 8364 hours (total availibility = 95,5%)

Total amount of running hours incinerators : 8396 hours

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Conclusion.

An ORC is a real added value for our heat recovery.

Even in winter we still have production of electricity.

Thanks to the GEC, the system is profitable. After the typical start-up problems, the ORC

runs smoothly with high availibility Little supervision necessary

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Future

There is a plan to build greenhouses of about 200.000 m² next to our ORC. We’ll use the cooling system to warm up the greenhouses.

There are plans to enlarge the town heating system: Up to 30 more industrial clients and 50 residential clients.

In this case, efficiency will decrease by a certain percentage, but the total recovery of energy will be very important.