Engineers India Limited Design Aspects of CTL Process With High Ash - PowerPoint PPT Presentation

Engineers India Limited Design Aspects of CTL Process With High Ash Indian Coal: An Efforts Towards Development of CTL Technology GASIFICATION INDIA 2017, NEW DELHI 6 - 7 December 2017

Overview of Coal to Liquids  CTL process: aspects of technology components  CTL Technology developments efforts  Methodology  Experimental facilities/pilot plants  Demonstration plant  Operating results/observations  Summary 11 December 2017 2

Coal to liquids (Transportation liquids) Direct coal liquefaction Indirect coal liquefaction • Mature & established but complex, less • High efficiency potential efficient • No aromatics, high-octane gasoline, • Low-octane gasoline, ultra-clean diesel low-cetane diesel • CO 2 capture & power co-production • Products w/ higher energy density • Use existing refining technologies • Water & air emissions issues • Meet all current & projected • Higher operating expenses specifications for sulfur & aromatic 3 • Suitable with low ash coal 11 December 2017 3

Incentives of CTL Technology Developments  Coal is relatively more abundant than oil and gas  Technologically Feasible  Significant advancements made over the years and undergoing major improvements currently  Economics  At present not encouraging but Capital and operating costs – downward trends  Expected to be more profitable in the rising prices of oil & gas scenario  CTL is an umbrella term for a group of technologies  Varieties of feeds stock > syngas > polygeneration  Energy security/ expanding energy basket 11 December 2017 4

PRODUCT FLEXIBILITY OF SYNGAS 11 December 2017 5

CHEMICALS Fuels from syngas Chemical CO/H2 Atom - combustion energy selectivity content of a product per Methanol 1 / 2 100 unit volume is an important Acetic acid 1 / 1 100 economic parameter Ethylene 2 / 3 100 glycol Chemicals from syngas Acetic 1 / 1 85 - generally sold by weight anhydride for their chemical performance., atom is an Propionic 3 / 4 80 important first factor to acid discriminate between the Methacrylic 4 / 5 73 various chemicals to be acid produced from syngas Ethanol 1 / 2 72 Acetaldehyde 2 / 3 71 Ethyl acetate 2 / 3 71 Vinyl acetate 4 / 5 70 Ethene 1 / 2 44 11 December 2017 6

REPORTED COMMECIAL USE OF SYNGAS  Largest - Manufacture of H2, more than half of which is used in the synthesis of ammonia.  The second largest - in the synthesis of methanol.  The third largest- conversion to paraffins, olefins and oxygenates via the Fischer-Tropsch reaction.  The fourth largest- the hydroformylation OXO reaction. The use of syn gas in the generation of electricity via IGCC has the potential for considerable growth. 11 December 2017 7

CTL through ICL Four Major Steps  Gasification:  Coal preparation, Coal Gasification, Syngas Cooling, Particulate Control  Syngas Purification:  Ammonia Scrubbing, Mercury Removal, Acid Gas Removal, CO2 Management  FT synthesis:  Catalysts, Reactors (LTFT/HTFT), Water Separations/Product Recovery  Product upgradation:  Hydrocracking, Hydrotreating, Isomerisation, etc. 11 December 2017 8

CTL through ICL Designers interest :  Throughputs of the different feedstock,  Optimal conditions for the design feedstock,  Gas compositions,  Heat effects,  Quench requirements  Startup and shutdown requirements,  Process control requirements. 11 December 2017 9

Problem due to high ash coals • Erosions of equipment and boiler parts • Difficulty in pulverization, • Poor emissivity, poor flame temperature. Low irradiative transfer, more unburnt carbons. • Excessive amount of fly ash and bottom ash, • Lower combustion efficiency, • Increase ash resistivity due to higher amounts of silica and alumina, reduction in ESP efficiency, • Increased emissions 11 December 2017 10

Gasification  Indian coals are characterized Moving Bed Gasifier: Fluidized Bed Gasifier: by  High ash content (~ 40%),  Low calorific value,  Low sulfur,  High reactivity and  High ash fusion temperature. Entrained Flow Bed :  Entrained bed gasification results in loss in efficiency due to inherent high ash content of coal/molten ash penetrations/refratory spoiling.  Fluidized bed gasifiers are more suitable to Indian coals. 11 December 2017 11

Gasification Exothermic: Gasifier Gas • Partial Combustion of Carbon Composition C + 0.5O2 ↔ CO; Δ H 0 298 = -110.5 kJ/mol  Key Issues with (Vol %) • Complete Combustion of Carbon Gasifiers C + O2 ↔ CO2, Δ H0 298 = -393.5 kJ/mol H 2 25 - 30  Kinetics (shrinking core?) • Water Gas Shift Reaction CO 30 - 60  Kinetic/equilibrium CO + H2O ↔ CO2 + H2, Δ H0 298 = -283.0 kJ/mol CO 2 5 - 15 Coal controlled? H 2 O 2 - 30 • Methanation  O2/Air Operating P, Temp C + 2H2 ↔ CH4 CH 4 0 – 5 Δ H0 298 = -74.5 kJ/mol  Coal/gas contact Steam CO + 3H2 ↔ CH4 + H2O, Δ H0 298 = -205.8 kJ/mol H 2 S 0.2 - 1 COS 0 - 0.1  Syn gas compositions Endothermic: N 2 0.5 - 4  Sizing of the gasifier • Boudard Reaction Ar 0.2 - 1 C + CO2 ↔ 2CO, Δ H0 298 = +172.5 kJ/mol  Effects of feed variations NH 3 + HCN 0 -0.3  • Steam Reforming Reaction Material of construction C + H2O ↔ CO + H2, Δ H0 298 = +131.3 kJ/mol  Engineering Aspects Ash/Slag/PM • Liberation of Bound Hydrogen  Scale-up 2H ↔ H2 , Δ H0 298 = +431.0 kJ/mol 11 December 2017 12

Contaminants in Syngas/Allowable Conc Element Conc in Coal Species Conc in Syngas H ₂ S, COS, CS ₂ 750-7000 ppmv as H ₂ S and 0.3 – 3.6 wt% S 25-200 ppmv as COS N 1.1 – 1.6 wt% NH ₃ , HCN 50-800 ppmv as NH ₃ Cl 0.003 – 0.37 wt% HCl, metal chlorides 170-830 ppmv as HCl 0.02 – 1 μ g/g Hg Hg (g) , Hg(CH 3 ) 2 1.3-63 ppbv 0.5 – 80 μ g/g As 2 (g) As 4 (g) , AsH 3 (g) 84-1300 ppbv As AsS (g) 0.2 – 1.6 μ g/g Se H ₂ Se (g) 32-2600 ppbv 0.1 – 3 μ g/g Cd (g) , CdS 11-340 ppbv Cd (condensed), CdCl 2 (g) Application Catalyst/Constraint S CO 2 Other Poison ≤ 40 ppm Power Environmental/Engineering ≤ 0.1 ppm Hydrogen Cr/Fe; Zn/Cu; Co/Mo Cl ≤ 0.1 ppm ≤ 10 ppm Ammonia Ni; Cr/Fe; Zn/Cu Cl, Hg, As ≤ 0.1 ppm SNG Cr/Fe; Zn/Cu; Ni Cl, Hg, As ≤ 0.1 ppm Fischer-Tropsch Co; Fe 11 December 2017 13

F-T Synthesis Syncrude (Long chain Synthesis Gas aliphatic HC, mainly n-paraffins) xH 2 +yCO F-T Reactor (Cat: Co/Fe) (-CH 2 -) n Available Technology: Fixed bed/Fluidized bed/Slurry bed 180-350 o C (-CH2-) n + nH 2 O -152 kJ/mol CO hydrogenation nCO + 2nH 2 20-35 bar Water gas shift CO + H 2 O H 2 + CO 2 - 41 kJ/mol Methanation CO + 3H 2 H 2 O + CH 4 -206 kJ/mol 11 December 2017 14

FT Reactor Types Slurry Reactor  Very high heat transfer rate Fixed Bed Reactor (FB)  High conversion per pass  Multitubular design  Higher catalyst activity with better  Diameter limited by slow heat selectivity removal  Catalyst regeneration by continuous purge  Good for heavy liquid & waxes and feed  conversion per pass is limited,  Uniform temperature distribution difficult to replace deactivated  Difficult to separate catalyst and Product catalyst 11 December 2017 15

Product Refining Long chain waxy HC Naphtha, Kero, Product Diesel, Waxes Refining (-CH2-)n  Hydroprocessing Section  Hydroisomerisation / hydrocracking of n-paraffins to iso-paraffins of desired length & boiling range  Mild hydrocracking at 300-350 deg C & 30-50 bar  Reactivity increases with increasing number of paraffins  Maximum yield of middle distillates  Minimum yield of C4 & lighters  Distillation Section  Conventional distillation for product fractionation  Gas Processing & Wax Finishing as necessary 11 December 2017 16

CTL Technology Development Efforts EIL-BPCL-THERMAX-CHT 11 December 2017 17

CTL Technology Development Approach GAS CLEAN ING SECTION GASIFIER SECTION PILOT PLANT TGA OPERATING DATA PILOT GASIFIER NOVEL SCHEME OPERATING DATA DESIGN METHOD GASIFIER MODEL DESIGN METHOD FT SECTION DEMO PLANT CATALYST DEV INTEGRATE A+B+C MICRO REACTOR FOR LARGE CAPACITY KINETIC DATA PROCESS PACKAGE COLD FLOW/CFD MODEL ENGINNERING REACTOR MODEL PROCUMENT DESIGN METHOD COMMISIONING 11 December 2017 18

Pilot plants and mathematical tools  HPTGA  Gasifier unit  Syngas cleaning unit  Cold stand Slurry column  Facilities for catalyst formulations/testing  Batch reactor/fixed bed/continuous for catalyst testing/FT kinetics  Mathematical model  Gasifier  Slurry bubble FT reactor  CFD model of SBCR 11 December 2017 19

Gasification Studies: Kinetics Using HPTGA  HPTGA along with MS for gas analysis have been installed at EIL-R&D complex  Design pressure: 50 bar  Design temp: 1100 0 C  Various type of coal viz. high ash coal, lignite, petcoke are being studied Objectives:  Investigations of coal gasification reactions at high pressure, high temperature, high ash coal  Insights to Coal gasification ‘reactivity’ 11 December 2017 20

HPTGA + MS Expt. Setup at EIL, R&D Lab P, T CONTROL GAS DOSING MICROBALANCE & SYSTEM SYSTEM SAFETY SYSTEM MS FOR ONLINE ANALYSIS 11 December 2017 21