History and Operating Results of a Coal Gasification Pilot Plant in Korea

Transcription

1 International Freiberg Conference on IGCC & GTL Technologies History and Operating Results of a Coal Gasification Pilot Plant in Korea Yongseung Yun, Seok Woo Lee, Seung Jong Lee, Young Don Yoo Plant Engineering Center Institute for Advanced Engineering Korea (

2 Background Korea imports 97% of total energy from abroad and thus must utilize the abundant worldwide coal resource to diversify the energy sources. For Korea, coal is an inevitable energy source to cover at least 3% of the necessary electricity at least during the next ten years. Unless a revolutionary method in energy generation is invented, IGCC or PFBC should be the most suitable technology when utilizing coal for power generation. Korea is in great need to adjust into more fuel-diversified society and to adopt environmentally benign technologies in power generation sector with higher efficiency and with low CO 2 emission. Korea has a plan to build a 3 MW class clean coal technology (CCT) power plant around the year 21, although CCT construction plan has been postponed twice. Since Korea cannot afford the cost in demonstration steps in IGCC technology, a pilot-scale gasification system of maximum 3 ton/day (T/D) capacity has been constructed and operated from 1994 with objectives of identifying key coal selection parameters as well as verifying technical feasibility by local manufacturing skill.

3 Projected Electricity Generation with Different Feedstock in Korea (unit: GWh, %) Year Nuclear Coal ,764 (4.5) ,83 (38.8) ,87 (36.7) ,72 (42.1) 11,945 (36.6) 127,153 (36.8) 156,448 (41.4) 169,87 (42.7) Domestic Coal 7,1 (2.3) 5,52 (1.6) 6,98 (1.6) 6,98 (1.5) LNG Petroleum Hydro etc. 29,684 (9.8) 45,638 (13.2) 43,73 (11.4) 26,48 (6.7) 26,666 (8.8) 24,87 (7.2) 23,995 (6.3) 17,889 (4.5) 5,982 (2.) 6,656 (2.) 8,3 (2.2) 8,542 (2.1) - 1,377 (.4) 1,32 (.3) 996 (.3) Total 33,42 (1) 345,216 (1.) 378,86 (1.) 395,812 (1.)

4 Gasification/Melting Research in IAE Coal, Coal, Wastes, Wastes, Low Low grade grade fuel fuel Gasification/melting Gasification/melting Clean Clean fuel/chemical fuel/chemical Zero Zero emission emission

5 View of 3 Ton/Day-Scale Coal Gasification Pilot Plant (Max. pressure: 28 bar, Max. temperature: 155 o C) (Control Room)

6 Process Flow of 3 T/D-Scale Coal Gasification System Coal (Bituminous, Subbituminous) Pneumatic transport Gravity transport Drier/Pulverizer (74 μm, moisture 2 4%) Hopper/Distribution hopper (feeding to 4 lock hoppers) Lock-hopper Feeders Pneumatic transport Coal feeding nozzles Hot Gas Desulfurization 55 o C 12 o C Syngas combustor Gas Engine System Hot Gas Filtering (Ceramic/Metal Filters) Syngas Cooling (Indirect Water Cooling) Coal Gasifier (Gasification, Melting)

7 Key Components of Pilot Plants Coal Gasifier with Feeding System High Temperature Filtering System Low Temperature Desulfurization System

8 Slip Stream Hot Gas Cleanup System

9 Typical Gasifier Operation Profiles Temperature ( o C) 16 Gasifier temperature CO CO 2 Gasifier pressure 12: 13: 14: 15: 16: 17: 18: 19: 2: H CO, H 2 and CO 2 gas composition (dry %, N 2 free basis) Gasifier pressure (kg/cm 2,gauge) Time (hr : min) (Indonesian Adaro coal)

10 Effect of temperature on the H 2 S and NH 3 gas concentrations 1 H 2 S H 2 S, NH 3 gas concentration (ppm) NH Temperature ( o C) (Indonesian Adaro coal)

11 Syngas compositions in N 2 -free basis from different scale gasifiers Gas composition 1 T/D 15 T/D 1) 1,89 T/D 1) / Gasifier scale CO H CO others (Australian Drayton coal) 1) Ref.: Ploeg, J.E,G., in Proc. of 4 th European Gasification Conference, Noordwijk, Netherlands (2).

12 Gasification data and conversion efficiencies for different scale gasifiers Data \ Gasifier scale 1 T/D 15 T/D 1) 1,89 T/D 1) O 2 /Coal weight ratio Steam/O 2 weight ratio.8 Cold gas efficiency (% LHV) Carbon conversion (%) ~ 99* 99.5** >98*, 99.5** Slag efficiency*** * single pass ** after fines recycle *** approximate value (Australian Drayton coal) 1) Ref.: Ploeg, J.E,G., in Proc. of 4 th European Gasification Conference, Noordwijk, Netherlands (2).

13 Syngas composition and gasification efficiencies with oxygen/coal ratio

14 Operation Results of Hot Gas Desulfurization System with Domestic Zinc Titanate-based Sorbent 4 4 Outlet H 2 S concentration / ppm Outlet Inlet Inlet H 2 S concentration / ppm Time / day (Indonesian Kideco Coal)

15 Operation Results of Hot Gas Filtering System with Ceramic Filters Gasifier & Reverse Pulse Jet N 2 Pressure [kg/cm 2 ] Filter Pressure Difference [centimeter Aq.] Filter Pressure Difference Reverse Pulse Jet N 2 Pressure Gasifier Pressure Filter Inlet Temperature Filter Outlet Temperature Syngas Flow Rate Reverse pulse jet cycle : 9 min, Reverse pulse jet time :.5 sec 19: 2: 21: 22: 23: : Operation Time [hour:min] Filetr Inlet & Outlet Temperature [ o C] Syngas Flow Rate [Nm 3 /h] (Indonesian Kideco Coal)

16 Coal Gasification - Slag, Syngas flame Produced slags after the gasification (5-1 bar, o C) (Unit: cm) Combustion flame of syngas

17 Slag shape and enlarged SEM picture of slag inner surface after gasification at 1-11 bar (Unit: cm) (x5) (Australian Drayton Coal)

18 Slag shape and enlarged SEM picture of slag inner surface after gasification at 14.5 bar (Unit: cm) (x2) (Australian Drayton Coal)

19 XRD results of ash and slags from Drayton coal Intensity (I/I1) (1) (2) Crystalline (1) CaSO 4 (2) SiO THETA combustion ash Intensity (I/I1) Amorphous Slags from 3 ton/day gasifier THETA 2 Intensity(I/I1) Amorphous Slags from commercial-scale gasifier THETA

20 Element analysis of slags obtained for Drayton coal from the pilot plant Pressure (bar) C(%) H(%) N(%) S(%) n.d n.d n.d.

21 Conclusions Because Korea expects that at least 3% of its electricity would come from coal during the early 21 st century, introducing environmentally acceptable technology like IGCC appears to be an inevitable choice of future. Feasibility of emulating the bigger scale gasification system including the commercial scale has been explored by comparing the results with the 1 T/D gasification pilot system. Coal gasification system yielded carbon conversion of above 98% and above 7% cold gas efficiency for the Indonesian subbituminous coals that were the best-suitable coals for gasification among the tested nine imported coals. Slags from the 1 T/D and 1,89 T/D systems both exhibit the similar shape and sizes as well as the similar amorphous inner structure, indicating that even smaller scale gasifier can effectively simulate the slag-forming behavior of the commercial-scale gasifier. Pilot system might provide the ability for technology evaluation when IGCC plant is imported in the near future in Korea.

22 References 1. Y. Yun and Y.D. Yoo, Comparison of Syngas and Slag from Three Different Scale Gasifiers using Australian Drayton Coal, J. Ind. Eng. Chem., 11(2), (25). 2. Y. Yun, Y.D. Yoo, and S.W. Chung, Selection of IGCC Candidate Coals by Pilot-Scale Gasifier Operation, Fuel Processing Technology, accepted for publication. 3. H.K. Jun, S.Y. Jung, T.J. Lee, The Effect of HCl and H 2 O on the H 2 S Removing Capacities of Zn-Ti-based Desulfurization Sorbents Promoted by Cobalt and Nickel Oxide, Korean J. Chem. Eng., 21(2), (24). 4. Y. Yun and J.S. Ju, Operation Performance of a Pilot-Scale Gasification/Melting Process for Liquid and Slurry-Type Wastes, Korean J. Chem. Eng., 2(6), (23). 5. C.K. Yi et.al., Simultaneous Experiments of Sulfidation and Regeneration in Two Pressurized Fluidized-bed Reactors for Hot Gas Desulfurization of IGCC, Korean J. Chem. Eng., 18(6), (21). 6. Y. Yun and Y.D. Yoo, Performance of a Pilot-Scale Gasifier for Indonesian Baiduri Coal, Korean J. Chem. Eng., 18(5), (21).