coal to liqued

8/22/2019 Coal to Liqued

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Confidential & Proprietary 1

Excellence Through Insight

Coal to Liquid

Sept 2011


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Coal Liquefaction

Coal can be converted to liquid fuels either by removalof carbon or addition of hydrogen

The first approach is know as carbonization, and the

second is know as liquefaction

The major objective of coal liquefaction is to produce

synthetics oil to supplement the natural sources of

petroleum.


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WHY CTL ?


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Advantages of Coal To Liquid(CTL) Fuels

CTL Improves national and economic security Lessens dependence on foreign oil

Provides environmental benefits

- Cleaner fuels that reduce NOx and particulate

emissions- Enables use of higher efficiency engines

Is capable of capturing CO2 emissions

Provides geographic diversity as energy source


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Coal Liquefaction

Very expensive

Liquefaction attractive for transportation fuel Indirect liquefaction commercially proven

(>50 yrs)

Acid gas removal by amines (CO2, H2S)

S removal by Claus Process

H2S + O2 = H2O + SO2H2S + SO2 = S + H2O


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Two Basic Approaches To Convert Coal To A Liquid Fuel

1. Direct Liquefaction: Dissolves coal in a solvent at elevated

temperature and pressure

Combined with hydrogen gas and a catalyst

2. Indirect Liquefaction: Involves first gasifying coal, followed by

reacting carbon monoxide and hydrogentogether

nCO + (2n+1)H2 = CnH2n+2 + nH2O


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Comparison of Processes

Adds hydrogen to break down

the coal

Dissolves in a solvent followed

by hydrocracking

Operates at 450 C and 170 bars

Light products are distilled

Medium and heavy distillates

obtained from vacuum distillation

Liquid yields of 70% of the dryweight of coal feed

Complete breakdown of coal

with steam and oxygen

Sulfur is removed from the

syngas

Syngas reacted over catalyst at

300 C and 30 bars

Produces a lighter suite of

products; high quality gasoline

and petrochemicals

Oxygenated chemicals

DIRECT

LIQUEFACTIONINDIRECT

LIQUEFACTION



SASOL in South Africa

Indirect Coal liquefaction is proven technology South Africas SASOL Co. developed a

commercial coal liquids industry (fuel plus

chemicals)



What is Gasification



Generic Coal Gasification Reactor



Gasifier types & Design Configurations



Different type of Gasification Process



Process Flow Chart for CTL

GasificationGas

Treating

AshDisposal

Naphtha

CoalH2

LPG

Diesel

GasolineProduct

Refining

F-T

Synthesis

SulfurRecovery

Hydrogen

Recovery



Acid Gas Removal (Rectisol)

Rectisol process for the removal of CO, H2S,Carbonly sulfide, organic sulfur compound,

HCN and condensable HC from the cooled

raw prodect gas


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Gas Liquor separation

Gas liquor produced in cool down of RG

GL contain dissolved gases such as crude gascomponents, NH3, Hydrocyanic acid, Tar, oil,phenols, chlorine, fluorine, fatty acids etc

Gaseous components are separated by flashing to

atm pressure. The liq and sold components areseparated by gravity separation.

GL fed to this unit is cooled & depressurized usingcontrol valves and a specially designed expansiondrum. The released gases are routed to the Sulfur

Recovery unit for H2S removal


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GL Separation


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Phenosolvan Process

Phenosolvan process consist of Two main

units : 16side Filtration

Extraction

Solvent recovery

17side

Deacidifer

Total Stipper

Ammonia Fractionators


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Total Stripper (X17VL-X04)


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Introduction


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(I) Normal Operation :


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Thank You !!!


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Low transportation cost

Less chemical transformation requiredHigher efficiency than high Btu gas

production

Easy to storeLess water required for manufacture

However, processing slurries at high

temperature and pressure presentsdifficulties with equipment life and

solid/liquid separation (still not commercial)

Direct Liquefaction of Coal Attractive Because of


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Gasifier Type

Fi h T h th i


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Fischer Tropsch synthesis

The purified synthesis gas leaving from Rectisol

unit undergoes FT synthesis wherebyhydrocarbons are produced by catalyticconversion of CO and H2

The FT process can be used to produce eitherlight synthetic crude(syncrude) oil and lightolefins or heavy HC

Syncrude can be refined to gasoline and diesel

Heavy HC to special wax or, if hyrocrackedand/or isomerizes, to produce diesel fuel, lubeoils and Nephtha

FT S th i


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FT Synthesis

FT synthesis can be generalized by the

following chemical reation

FT S th i


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FT Synthesis

FT P


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FT Process

Methanol S nthesis


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Methanol Synthesis

Synthesis of Methanol from Syngas

Synthesis of Dimethylether (DME) from

Methanol

Synthesis of DME directly from Syngas

Synthesis of Methanol


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Synthesis of Methanol

Synthesis gas preparation


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Synthesis gas preparation

Feed gas introduced to Methanol synthesis loop must

contain the correct proportions of CO, CO2 and H2

Synthesis gas composition adjusted by shift reaction

and steam reforming

RG from purification section contains methane

which is unwanted component in synthesis feed

The methane and other light HC produced are split

into H2 and CO by steam Reforming

Operating condition of Methanol


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Operating condition of Methanol


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coal to liqued

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