PLASMA ASSISTED GASIFICATION OF COAL FOR THERMAL POWER PLANTS APPLICATION

Transcription

1 PLASMA ASSISTED GASIFICATION OF COAL FOR THERMAL POWER PLANTS APPLICATION Prof. E.I. Karpenko, Prof. V.E.Messerle, Dr. A.B.Ustimenko NTO Plasmotekhnica Ltd., Almaty, Kazakhstan Research Institute of Experimental and Theoretical Physics, Kazakh National University, Almaty, Kazakhstan New Horizons in Gasification The12th European Gasification Conference March 2014, Rotterdam, The Netherlands 1

2 Problem WORLD ENERGY RESOURCES % % 6 1.9% % Conventional (fuel oil) start up of a pulverized coal boiler and pf flame stabilization % 2 6.9% 1 coal, 2 oil fuel, 3 gas, 4 nuclear power, 5 waterpower, 6 renewable. (Key World Energy Statistics)

3 Solution The technology is based on plasma thermo- chemical preparation of coal for burning and allows substituting of gas or fuel oil by coal. Sketch of Plasma-Fuel System (PFS).

4 BASIC PRINCIPLES OF THE PLASMA TECHNOLOGY Temperature of the plasma flame can reach K. Thermochemical preparation of coal to burning is realized in the PFS for rich coal/air mixtures ( kg of coal per one kg of air). Concentrations of gaseous and solid components depend on the process temperature. 4

5 BASIC PRINCIPLES OF THE PLASMA TECHNOLOGY Products of the plasma activation of pulverized power coal Gas Phase Composition (vol.%) H 2 CO CH 4 C 6 H 6 CO 2 H 2 O N 2 O 2 A C, kg/h C C, kg/h Gas temperature (К) Solids Temperature (К) Velocity of the flow (m/s)

6 BASIC PRINCIPLES OF THE PLASMA TECHNOLOGY Features of interaction of electric-arc plasma with air-fuel mixture in plasma-fuel system for coal ignition Coal particles of micron in plasma undergo heat shock, as a result they are crushed into fragments, each fragment is of a size of 5-10 micron. It is a result of intensive yield of coal volatiles (CO, CO 2, H 2, N 2, CH 4, C 6 H 6 etc.) and accelerates the process of fuel combustion 3-4 times 6

7 Plasmatron Plasmatron is the main element of the plasma-fuel system Arc burns between a cathode and anode and ionizes plasma gas, blowing through the arc. The plasmatron s arc power varies from 100 to 250 kw. The plasmatron has main dimensions: length 0.5 m, diameter 0.25 m. It s weight is about 25 kg. 7

8 PLASMATRON 8

9 PLASMA-FUEL SYSTEM Plasma torch in operation 9

10 EXPERIMENTAL PFS OPERATION Coal consumption through the PFS 2000 kg/h 10

11 EXPERIMENTAL PFS OPERATION Coal consumption through the PFS is 1000 kg/h, heat power is 5 mw 11

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13 Industrial trials Thermotechnical characteristics of coals. Coal Type W w, % A d, % V daf, % Q w l, kj/kg Shale Lignite Brown Bituminous Anthracite Mixture of coals Note on abbreviations: W w is moisture on dry basis; A d is ash content on dry basis; V daf is volatilisation on dry basis; Q w l is low calorific value on dry basis 13

14 Variety of the pf boilers and burners contractions Boilers furnaces equipped with PFS (top view), and PFSs

15 Industrial trials Scheme of the PFS arrangement on 640 t/h steam boiler: Gusinoozersk TPP, Russia. 15

16 Industrial trials Duration of the PFS operation at the coal consumption rate 2 t/h 1 min 5 min 3 m 5 m Image of the pulverised coal flame initiated in the PFS during boiler start up from cold condition 16

17 Industrial trials Pulverised coal flame plasma stabilisation in a furnace of industrial boiler 17

18 Numerical experiment million 420 t/h steam boiler furnace equipping with PFS (Almaty TEC-2, Kazakhstan) : 1 main pulverized coal burners, 2 PFS. 18

19 Layout of two stage PFS for the boiler BKZ-420 of Almaty TEC-2 1 channel of the external flow of pf, 2 secondary air duct, 3 - inlet of pf external flow, 4 inlet of pf internal flow, 5 - plasmatron, 6 chamber for pf flow turning, 7 chamber for plasma chemical preparation of fuel for combustion, 8 - chamber for mixing and thermochemical preparation of fuel, 9 - furnace 19

20 Initial parameters for PFS computation Parameter Value Plasmatron power, kw 200 Air-coal mixture temperature, К 362 Consumption of coal through PFS or internal channel of the burner, kg/h 6000 Рrimary air rate, kg/h 8955 PFS length, m Pulverized coal composition, mas. % Ash C H 2 H 2 O CO CO 2 CH 4 C 6 H Composition of highly reactive fuel at the PFS exit Composition of gaseous phase, vol. % Ash, C, H 2 CO CH 4 C 6 H 6 CO 2 H 2 O N 2 O 2 kg/h kgh Gas temperature, К Solids temperature, К Flow velocity, m/s

21 T, K Numerical experiment Ci, % N H 2 O 2 CO 2 CO H 2 O 800 C 6 H CH X, m X, m Gas (1) and particles (2) temperature (T) distribution along the PFS (X). Gas components concentration (C i ) distribution along the PFS (X). 21

22 Temperature field in the plane of the central burners and the PFS Conventional incineration of coal Plasma assisted incineration of coal using three PFS 22

23 Variation of averaged СО 2 concentration along height of the 420 t/h steam boiler furnace 1 Regime with PFS 2 Conventional regime of coal incineration 23

24 View of pf flame from PFS in boiler s window in the first minutes of the start up 24

25 Industrial trials Russia Kazakhstan China Mongolia Korea Serbia Slovakia 2000 Ukraine States concerned Germany Italy USA India Turkey

26 Concurrence Conventional technology Plasma technology 1. Fuel Oil Rate for Russian TPP 5.1 mln. t/year (cost is more than $ 2.5 billion) 2. Fuel Oil Rate for Kazakhstan TPP ~1 mln. t/year (cost is about $ 500 mln.) 3. Investments for TPP 100% 3-5% 4. Operating costs 100% 28-30% 5. Electric power consumption for TPP auxiliary 3-5% % 0 0 NOx reduction 500 ppm 250 ppm Unburned carbon reduction 4 % 1 %

27 Conclusion