IGCC for Power generation

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IGCC for Power generation
An Environmentally Benign

Energy Efficient Technology

• By
• Dr. D.N. Reddy, Director
• Er. K. Basu, Adviser Dr. V.K. Sethi, Research
  AdviserCentre for Energy Technology,
  University College of Engineering (Autonomous)
  Osmania University, Hyderabad 500 007, India.

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• Total installed capacity over 1,00,000 MW
• Thermal power generation has emerged as the
  principal source of electric power in India
  contributing to about 70
• Coal fired thermal stations are in predominance
  and share about 84 of the total thermal
  installed capacity.
• It is prudent and economical to develop methods
  and process for efficient utilization of
  low-grade Indian coals for power generation.

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• Gasification of coal is the cleanest way of
  utilization of coal, while combined cycle power
  generation gives the highest efficiency.
• Integration of these two technologies in IGCC
  power generation offers the benefits of very low
  emissions and 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 the
  corresponding emissions from PC plant.

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• Environmental performance of IGCC thus far
  exceeds that of conventional and even
  supercritical plants.
• Three major areas of technology that will
  contribute to improvements in IGCC are
• hot gas de-sulfurisation
• hot gas particulate removal
• advanced turbine systems

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• Commercialization of IGCC needs technology
  demonstration 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 optimum
  module for air blown gasification, which in
  multiples would constitute a commercial size
  plant in the range of 300-600 MW.
• The present study addresses these issues and
  suggests suitable technologies for Indian Coals.

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VISION 2020 PROGRAM
In-combustion Clean-up Fluidized bed combustion
(CFBC, PFBC, AFBC)
Gasification using fluidized bed, moving bed or
Entrant bed Gasifiers
Post combustion Clean-up-Desulfurization(FGC
systems) Supercritical
Pre combustion Clean-up beneficiation/washing
CLEAN COAL TECHNOLOGIES
Technologies for utilization of Coal for Power
Generation with minimal pollutants discharged to
the atmosphere (Reduced CO2, Sox, Nox, SPM) at
high conversion efficiency.W.C.I.
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Schematic Layout of the Integrated Gasification
Combined Cycle
Steam
Flue Gas to Stack
Steam
BFW
HRSG
Steam Turbine
Steam
Coal
Compressed Air
Hot Gas
Fuel gas
Gasifier
Gas Cleanup
Gas turbine
Power
Ash
Sulfur
Air
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Comparison of various Power Plants
High efficiency coupled with low emission
(SPM 7, Sox16, Nox21 of
corresponding PC Plant) For Indigenous Units
through systematic transfer of Technology
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Identified RD Areas are

• Process optimization of selected gasification
  process
• Improvement of design and reliability of plant
  components Resource Optimization
• Optimization of overall plant heat integration
  and layout
• Hot gas cleanup

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COAL GASIFICATION SELECTION OF GASIFICATION
PROCESS

• The fluidised bed process has many technical and
  environmental advantages over the moving bed
  process, such as,
• The fluidised bed can use any amount of fines
  whereas in the 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 produced and, hence, the pollution is
  reduced.
• High ash coals can also be successfully gasified
  in the fluidised 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
  of conversion and reduced SPM, SOx, NOx levels
  can be achieved using coal based IGCC
  technology.
• Retrofit/Re-power options for gas based CCGT
  plants by installing only coal based gasifiers
  are cost effective (opportunity cost low) and
  are environmentally benign.
• Adoption of IGCC technology in India has
  Global as well as National benefits.

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IGCC DEVELOPMENT PROGRAM IN INDIA

• Pioneering work on IGCC development in India
  taken up by BHEL in early eighties.
• Major Mile Stones
• Choice of gasification for high ash coals by
  BHEL
• 6.2 MW IGCC demonstration plant established
  by BHEL both with moving Bed and Fluidized bed.
• Coal characterization by BHEL IICT for
  gasification application.
• Intensive data generated by IICT on oxygen-steam
  gasification in their moving bed gasifier.
• Task force CEA, CSIR, NTPC BHEL constituted
  to assess technological maturity financial
  requirement for a green field IGCC plant of
  100 MW capacity at Dadri (NTPC).
• BHEL, CSIR NTPC prepared proposal for
  setting up of this 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 is
  only for low ash coals.
• Thus there is a need for taking up extensive
  RD 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
  particulate removal)
• 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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Fuel related 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
  Cycle optimization 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 about 2 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 equally attractive to coal based
  IGCC from economic and environmental
  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 TOT of 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 coke
• Normal 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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