energy efficient technology

8/4/2019 Energy Efficient Technology

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IGCC for Power generation

N.T.P.C GAS PLANT DADRI


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Total installed capacity over 1,00,000 MW

Thermal power generation has emerged as theprincipal source of electric power in Indiacontributing to about 70%

Coal fired thermal stations are inpredominance and share about 84% of thetotal thermal installed capacity.

It is prudent and economical to developmethods and process for efficient utilization oflow-grade Indian coals for power generation.


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Gasification of coal is the cleanest way of utilizationof coal, while combined cycle power generation givesthe highest efficiency.

Integration of these two technologies in IGCC power

generation offers the benefits of very low emissionsand efficiencies of the order of 44-48%.

The comparative indices show that in case of IGCC,

emission of particulate, NOx and SOx are:7.1%, 20% and 16%, respectively, of thecorresponding emissions from PC plant.


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Environmental performance of IGCC thusfar exceeds that of conventional and evensupercritical plants.

Three major areas of technology that willcontribute to improvements in IGCC are :

hot gas de-sulfurisation

hot gas particulate removal advanced turbine systems


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Commercialization of IGCC needs technologydemonstration at an intermediate scale of about

100 MW to address the issues such as:hot gas clean ups and system optimization and

to establish reliability and performance.

This would also enable to design an optimummodule for air blown gasification, which inmultiples would constitute a commercial sizeplant in the range of 300-600 MW.

The present study addresses these issues andsuggests suitable technologies for Indian Coals.


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VISION 2020

PROGRAM

Post combustion Clean-up-Desulfurization

(FGC systems) Supercritical

In-combustion Clean-upFluidized bed

combustion (CFBC,PFBC, AFBC)

Gasification using +fluidized bed, moving bedor Entrant bed Gasifiers

Pre combustion Clean-up beneficiation/washing

Technologies for utilization of Coal for Power Generation with minimalpollutants discharged to the atmosphere (Reduced CO2, Sox, Nox,

SPM) at high conversion efficiency.W.C.I.

CLEAN COALTECHNOLOGIES


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Gasifier Gas Cleanup Gas turbine

HRSG Steam TurbineSteam

Hot Gas

Power

BFW

Steam Flue Gas to Stack

Steam

Coal

Ash Sulfur Air

Fuel gas

Compressed Air

Schematic Layout of the

Integrated Gasification Combined Cycle


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Comparison of various Power PlantsPower Plant

ConceptsMajor Components Efficiency %

Cost per

MW (Rs.

Crore/MWPC fired

Thermal

Boiler, Steam turbine, Coal

handling and other BOP34-37 3.8-4.0

CC PlantGas turbine, Steam turbine, Waste

hear recovery boiler40 3.2-3.4

IGCC (Coal)

Coal preparation unit, gasifier,

steam turbine, Gas cleaning GT,

WHTSG

46* (estimated) 4.86-4.95**

IGCC (Pet

Coke)

Air separation unit GT, ST,

WHRSG, Gas Clean up

48* (with G/H

class Gas

turbines)

4.25-4.30**

Super CriticalAs for PC fired Thermal plus spiral

tubes and high temp alloys37.5-39.5 3.95-4.10

* High efficiency coupled with low emission (SPM: 7%,

Sox:16%, Nox:21% of corresponding PC Plant)

** For Indigenous Units through systematic transfer of Technology


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Identified R&D Areas are:

Process optimization of selected gasificationprocess

Improvement of design and reliability of plantcomponents & Resource Optimization

Optimization of overall plant heat integration and

layout

Hot gas cleanup


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COAL GASIFICATIONSELECTION OF

GASIFICATION PROCESS

The fluidised bed process has many technical and environmentaladvantages over the moving bed process, such as,

The fluidised bed can use any amount of fines whereas inthe moving bed only 10% of fines can be used.

In the fluidized bed process, hydrocarbon, liquid by-products such as tar, oil and gas-liquor are not producedand, hence, the pollution is reduced.

High ash coals can also be successfully gasified in thefluidised bed.


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BENEFITS EXPECTED FROM IGCC

India endowed with large coal reserves over 200 billion

tonnes.

Environmental benefits due to higher efficiency ofconversion and reduced SPM, SOx, NOx levels can be

achieved using coal based IGCC technology.

Retrofit/Re-power options for gas based CCGT plantsby installing only coal based gasifiers are cost effective

(opportunity cost low) and are environmentally benign.

Adoption of IGCC technology in India has Global aswell as National benefits.


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IGCC DEVELOPMENT PROGRAM IN INDIA

Pioneering work on IGCC development in India taken upby BHEL in early eighties.

Major Mile Stones

Choice of gasification for high ash coals by BHEL

6.2 MW IGCC demonstration plant established by BHELboth with moving Bed and Fluidized bed.

Coal characterization by BHEL & IICT for gasificationapplication.

Intensive data generated by IICT on oxygen-steamgasification in their moving bed gasifier.

Task force CEA, CSIR, NTPC & BHEL constituted toassess technological maturity & financial requirement fora green field IGCC plant of 100 MW capacity at Dadri(NTPC).

BHEL, CSIR & NTPC prepared proposal for setting up ofthis 100 MW IGCC demonstration plant.


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Experience on the fluidized bed process is,very limited in the country.

Internationally, the experience gained so far isonly for low ash coals.

Thus there is a need for taking up extensiveR&D on IGCC Pilot Plant using high ash (40-50% Ash) Indian Coals.


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Technology-related issues in IGCC

Design of Advanced gasifiers (optimum gas

composition, optimum scale-up etc.)

Hot gas cleaning (de-sulphurisation and particulateremoval)

Advanced gas turbines (blade design to sustain ash

laden gas)

CO2 emission abatement in IGCC Power Plants

Operating conditions of IGCC plants in transient stage

Configuration of an optimized system for IGCC


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Fuelrelated issues

In a Raw Pet-Coke and refinery residue based IGCC Plant

System optimization, particularly the balance of plant

Optimized Heat balance diagrams

Scaling up of gasifiers to optimum size

In a Coal/Lignite based IGCC Plant Process & Plant conceptual design

De-sulfurization of syngas of high sulfur coal and lignite

Optimized Heat balance diagrams

Super critical Vs IGCC in Indian context

Application of ASME PTC-47 code for IGCC for high ash coals and

lignite


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SOME IMPORTANT FINDINGS

Reactive solid sorbent de-sulfurization combined with hot

gas cleaning through ash and sorbent particle removal

provides for higher energy efficiency to an extent of 4-7%.

The current Capital cost of building an IGCC power plant is

of the order of Rupees 6 crore/ MW.

Improvements in hot gas cleaning coupled with Cycleoptimization shall bring down the cost drastically to a level

of $ 1000/kW or about Rupees 4.5 crore/MW


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The efficiency of refinery bottom based IGCC unit will be about2% higher than that of coal based IGCC unit.

Refinery based IGCC plants - Advantages

Co-generation of steam

Co-production of hydrogen gas & recovery of sulfur element

No use of limestone, as required for CFBC technology

No requirement of extra land for disposal of solid waste

In the long run the refinery based IGCC technology is equallyattractive to coal based IGCC from economic andenvironmental considerations.


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SOME FINDINGS RELATED TO

COMMERCIALIZATION OF TECHNOLGOY

At present it may be prudent to implement the project in

phased manner to absorb the risk of gasifier in the total

project wrap-up guarantees fig. 1

A Technology Transfer model for determination of velocity

of Transfer of Technology (TOT) is an useful tool for TOTof a frontier technology from a developed economy to a

developing economy fig. 2


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Typical results of the velocity of TOT are : -

(With year 2000 as base)

IGCC (oxygen blown) - Pet cokeNormal pace ---- 5 years

Accelerated ---- 2 years

(Fig 3)

IGCC (Air Blown) ---- Coal

Normal pace ---- 7 years

Accelerated ---- 5 years

( Fig 4)


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Fig. 1


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Fig. 2


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Fig. 3


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Fig. 4


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Fig.5 EFFICIENCY IMPROVEMENT FORECAST

CONVENTIONAL Vs IGCC

60

55

50

45

40

35

301990 1995 2000 2005 2010

Year of commercial use

NetTherm

alEfficiency(%)

Ceramic gas

turbine

566 Co600 Co

623 Co1300 Co 1500 C

o

540 Co

650 Co1184 Co

IGCC (15 C Amb)IGCC (Indian Condition)

Super Critical PC Power Plant (15 C Amb.)o

Super Critical PC Power Plant (Indian Condition)o

Sub Critical PC Power Plant (Indian Condition)


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