WASTE HEAT RECOVERY POWER PLANT - CEMENT PLANT.docx

7/27/2019 WASTE HEAT RECOVERY POWER PLANT - CEMENT PLANT.docx

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WASTE HEAT RECOVERY POWER PLANT

SK.ANWAR BASHA

Posted by Yuva Engineers on April 30th, 2010

Technical Paper Title: WASTE HEAT RECOVERY POWER PLANT

Authors: SK.ANWAR BASHA, 3rd BTech, EEECollege: Prakasam Engineering College, Kandukur

AbstractA large quantity of Flue gases at high temperatures is produced by different parts of the heavy

industries. They are purified internally by purifying equipment like Electrostatic Precipitators and are left

into atmosphere. At the present condition the heat energy of flue gases is wasted. If we are able to trap the

heat and thereby using the heat to produce steam, an efficient electric power generation can be achieved.

As the heavy industries are located independently and in many cases, neither steam nor hot water is needed

in their own plants. The recovery in electric power is most effective method . On the other hand, the main

advantages offered by the Waste Heat Recovery PowerPlant can be listed as follows:

1) Clean power generation

2) No production of green house gases (ex: CO2)3) No air polluting gases (NOx, SOx).

4) Reduces 10-12% ofGlobal wAarming effect.

The recovery plants can be constructed on the same basis of the thermal power plant with the only difference

that flue gases for the production of heat in boilers replace the burning of coal. This difference makes the

recovery plant most efficient and clean over conventional plant for same power rating .

Hence this project can be treated as the efficient method of utilization of waste gases for the production of

electrical energy and one can hope that the Waste Heat Recovery will play an even great role in the

industrial development of 21st century.

WASTE HEAT RECOVERY POWER PLANTWaste heat recovery is the process of capturing waste heat (thermal) energy for beneficial

purposes. Recaptured heat energy is potentially useful for generatingelectricity. Space heating, water

supply and green houses. Heat recovery is a complex system, which requires many parameters to be

considered. The exit temperature of the waste heat as well and the application of the regenerated waste heat

is key factors in heat recovery systems. There are three temperature ranges of heat recovery. In small, waste

heat in industries is recovered from liquids or gases at low temperatures (below 450o F [232oC]) . In larger

industries, medium temperature recoverable heat (between450o F and 1200o F [232o C649o C]) may be

available for waste heat recovery. High temperature recoverable heat (above 1200o F [649o C]) is usually

available only in heat-intensive industries i.e.,

Heavy Industries Generating Waste Heat Power and Utility Industries

Heavy Industries: Steel, Aluminum, Copper, Cement, Pulp & Paper, Glass,

Soda Ash and Waste Recycle

Refinery, Petrochemical and Gasification plants

Chlor-Alkali & Vinyl plants

Incinerators, Waste to Energy

Typical Waste Heat Sources Fired boilers, gasifiers, heaters/furnaces (gas, diesel, coal, nuclear, refuse, pet


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Gas turbine exhaust continuous, standby, peaking, combined cycle units

Steam turbine exhaust: and vented steam

Internal Combustion (IC) engine exhaust

The total heat generated in these industries is not utilizing full fledged but 45% is discharged through the

exit gases from the preheater and through chimney and the gases which are releasing in to atmospherethrough this waste heat are

NOx & Sox Mercury Vaporized heavy metals etc..,

And these gases are causing dangerous health problems to people who are leaving surroundings to these

industries and indirectly it is forming 10-12% ofglobal warming effect.

If we are able to trap the heat and thereby using the heat to produce steam, an efficient electric power

generation can be achieved by this waste heat

The recovery in electric power is most effective method. On the other hand, the main advantages offered bythe Waste Heat recovery power plant can be listed as follows:

Clean power generation No production of green house gases (ex: CO2) No air polluting gases (NOx, SOx) etc

The waste heat recovery plants can be constructed on the same basis of the thermal power plant with the

only difference that flue gases for the production of heat in boilers replace the burning of coal. This

difference makes the recovery plant most efficient and clean over conventional plant for same power rating .

We can place Waste Heat Recovery plant in many heavy industries (Steel, Aluminum, Copper, Cement,

Pulp & Paper, Glass, Soda Ash etc..)which are producing huge amount of waste heat.

Suppose if we place Waste Heat Recovery Power Plant in Cement industry thelayout diagram will be

like this.In Cement plants, about 90% of total energy is used as heat energy in clinker burning process. Out of total

heat consumed in the burning process, around 55% of the heat is utilized for clinker burning and rest 45% is

discharged as sensible heat through the exit gases from the preheater (PH), Air Quenching Chamber (AQC),

as radiation losses and sensible heat carried out by the clinker.Around 8% of heat from the exit gases of

preheater and AQC is used effectively for drying the raw materials and coal. The rest 37% is often emitted

to the atmosphere without utilization

In Cement industries large portion of the energy consumption for the production of cement occurs in the

calcinations process in clinker production.This involves passing the ground raw materials through a pre-

heater stack containing cyclone heaters to a long rotating kiln to create clinker and then cooling this in the

clinker cooler. Waste heat is typically mainly vented to atmosphere and if captured and used for power

generation, as proposed in this Project Activity, can lead to significant greenhouse gas emission reductions .The layout diagram will be like this:


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The production process of this project is an energy conversion process. Feed water recovers the heat energy

of low-temperature waste heat exhausted by clinker production line through PH heat recovery boiler and

AQC heat recovery boiler, to convert it into superheated steam, and then steam is fed into steam turbinethrough the steam pipe. The heat energy is converted into kinetic energy in steam turbine to enable turbine

rotor to rotate at high speed, and then drive the generator to rotate, and final productelectric energy is

generated.

Coming in to operation of W H Rin cement industries, the calcinations process of clinker wastes a lot of

energy. The amount of the heat contains in the low temperature (lower than 400 C) waste gas, which is

vented by the PH- Boiler and Air Quenching Chamber (AQC), is more than 37 percent of the total amount

of the heat consumed in the calcinations process of clinker. The proposed project activity adopts waste-

heat recovery technology to utilize waste heat from PH and AQC for power generation

In the project activity, the project entity has equipped a WHR system for the cement clinker production

line. The WHR system in the project activity consists of one set of PH boiler, one set of AQC boiler, one

steam turbine generator, and water circulation system and dust-removal system etc. The AQC boiler hasbeen installed between the exhaust exit at the middle of the kiln entry clinker and the exhaust electric

precipitator at kiln front. The first section of the AQC boiler produces overheated steam and the second

section produces hot

water. The PH boiler has been installed between the exhaust exit of the kiln rear pre-heater and the kiln rear

high-temperature fan. Steam turbine generator has equipped for the two boilers. The waste heat from PH and

AQC will be fed to PH boiler and AQC boiler to generate steam . The steam from SP boiler and AQC boiler

will be united and fed to steam turbine generator for power generation.

Expected Power Generation:
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ADVANTAGES: 30% of the plant power consumption is met by the internal generation

through waste heat recovery

40%of the waste heat is recovered Reducing the carbon dioxide emission into atmosphere by about 45,000 tons per year 30% offpower is saved for producing ton cement Economical for1 MW to 25 MW Power Plants.

v Electrical Power generation potential from Waste Heat Recovery power plant is below
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v Cost comparison ofWaste Heat Recovery PowerPlant with other sources ofPowerPlants:

v Cost comparison ofWaste Heat Recovery PowerPlant with Renewable Energy Recourses
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Advantages ofWaste Heat Recovery PowerPlant (REUSABLE ENERGY):

Each MW of Power Generation (compared to coal fired plant) Eliminates : Each MW of Power Generation (compared to coal fired plant) Eliminates :

21 Tons NOx

59 Tons Sox

8615 Tons of CO2

Power Generated withZero Emissions

Renewable Energy Credits

Integrated Multi-Pollutant Reduction System

Zero Emission Power Plants

Efficient Power from Flue Gas, Steam, Hot Water/Fluids

Saves Valuable Water Resources

High Internal Rates of Return

Supports Distributed Generation

Solar, Biomass & Geothermal Standalone Power Plants
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Combined Cycle Diesel Engine Power Plants

Provides Emission Credits

By all this Advantages,

WHY NOT CLASSIFY REUSABLEENERGYAS RENEWABLEENERGY?

Conclusion:

Heat recovery technology is an excellent tool to conserve energy. The WasteHeat Recovery brings in relatedeconomic benefits for the local community and would lead to sustainable economy and industrial growth in

the region. The W H Ractivity would be able to replace electricity generated by grid-connected power plant

thus saving further exploitation and depletion of natural resourcescoal, or else increasing its availability to

other important process.

The electricity generated from the W H Rwould help to reduce carbon dioxideemission and other

associated pollution at thermal power plats

By placing Waste Heat Recovery power plants in heavy industries which are generating huge amount of

waste heat, we can reduce 10-12% ofGlobal Warming effect. This will help full forNation too

This project can be treated as the efficient method of utilization of waste gases for the production of

electrical energy and one can hope that the Waste Heat Recoverywill play an even great role in the

industrial development of 21stcentury.Both comments and pings are currently closed.

WASTE HEAT RECOVERY POWER PLANT - CEMENT PLANT.docx

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