Multi-gas AC plasma torches for gasification of organic substances

Institute for Electrophysics and Electric Powerof Russian Academy of Sciences (IEE RAS)

St. Petersburg, RussiaIEE RAS

Alexander Surov, S. Popov, V. Popov, D. Subbotin, E. Serba,V. Spodobin, Gh. Nakonechniy

8th International Freiberg Conference in Cologne, Germany 12 - 16 June 2016

• does fundamental and appliedresearch in electrophysics, plasmaphysics, power engineering andelectrical power engineering

• was established in 1992• has a staff of 140 people, of which

70 are scientists• is located in Saint-Petersburg,

Russia, has a central office in townand test benches in suburbs

Professor Philip RutbergIEE RAS

Electric Arc AC 3-Phase Plasma TorchPower from 3 to 80 MW

Dvortsovaya emb.18, St. Petersburg, RUSSIA

AC 50 Hz (three-phase)Open-circuit Voltage – 380/480 VShort-circuit Current – 500/700/1000/1500APlasma-forming Gas - AIR and others

5 kW 500 kW

75 kW

IEE RAS AIR AC PLASMA TORCHES

Working gas – AIRFlow rate 0.5÷70 g/s

ONE-PHASE HIGH VOLTAGE AC PLASMA TORCHWITH ROD ELECTRODES

Plasma forming medium – air 1-4 g/sVoltage – AC 6 kVCurrent – up to 14 APower – up to 15 kWEfficiency – ~95%Electrodes life time – up to 300 hours

THREE-PHASE HIGH VOLTAGE AC PLASMA TORCH WITH ROD ELECTRODES

Plasma forming medium – air up to 35 g/sVoltage – AC 3x6/10 kVCurrent – up to 50 APower – up to 75 kWEfficiency – up to 95%Electrodes life time – up to 200 hours

Schematic diagram of the experimental installation

1 – Power supply,2 - high-voltage three-phase plasma torch with cylindrical (hollow) electrodes,3 – arc column,4 – hollow cylindrical electrode,5 – solenoid,6 – pipe hole for photo and video shooting,7 – terminal for connection of the power supply,8 – tangential plasma forming gas flow,9 – high-speed video camera,10 – acquisition system.

THREE-PHASE HIGH VOLTAGE AC PLASMA TORCHWITH HOLLOW ELECTRODES

Shutter speed 1/4000 s

IEE RAS

№ Flow rate, g/s

Gas velocity magnitude in

the arc attachment

area, m/s

Tangential gas velocity in

the arc attachment

area, m/s

Speed of the arc

attachment, m/s

Field density in the arc

attachment ×10-3 T

Current intensity in the arc, A

1 5 14.28 14.33 4.510.7 47.32 9.4 26.85 26.82 8.8

3 12.2 34.67 34.63 10.7

THREE-PHASE HIGH VOLTAGE AC PLASMA TORCHWITH HOLLOW ELECTRODES

THREE-PHASE HIGH VOLTAGE AC PLASMA TORCHWITH HOLLOW ELECTRODES

Plasma forming medium –air up to 100 g/s

Voltage – AC 3x10 kVCurrent – up to 100 APower – up to 500 kWEfficiency ~ 92%Electrodes life time –

up to 2000 hours

40 50 60 70 80 90 1002100

2200

2300

2400

2500

2600

2700

Volta

ge d

rop,

V

Current, A

60 70 80 90 100 110 1202000

2200

2400

2600

2800

3000

280300320340360380400420

Powe

r, kW

Voltage drop

Volta

ge d

rop,

V

AIR mass flow rate, g/s

Power

60 70 80 90 100 110 1203,5

4,0

4,5

5,0

5,5

2600

2800

3000

3200

3400

Enthalpy, MJ/kg Bulk

tem

pera

ture

, K

Enth

alpy

, MJ/

kg

AIR mass flow rate, g/s

Bulk temperature, K

PARAMETERS OF THREE-PHASEHIGH VOLTAGE AC PLASMA TORCH

WITH HOLLOW ELECTRODES

THREE-PHASE HIGH VOLTAGE AC STEAM PLASMA TORCHWITH ROD ELECTRODES

Plasma forming medium – steam + airVoltage – AC 3x10 kVCurrent – up to 50 APower – up to 105 kWEfficiency – ~95%Electrodes life time – up to 200 hours

STEAM-AIR PLASMA TORCH PARAMETERS

MULTI-GAS AC PLASMA TORCH PARAMETERS(OPERATING ON CO2/H2O/CH4 MIX)

GCO2 = GH2O = 3 g/s

TEST INSTALLATION FOR METHANE REFORMING

0,8CH4 + 0,2CO2 + 0,6H2O → 2,2H2 + CO

METHANE REFORMING EXPERIMENTAL DATA :SYNGAS CONTENT FOR DIFFERENT PLASMA FORMING GAS COMPOSITION

CH4 – 3.5 g/sCO2 – 2.9 g/sH2O – 2.9 g/s

CH4 – 2.4 g/sCO2 – 6.9 g/s

SHEMATIC OF IEE RAS TEST FACILITY

1- DOWNDRAFT GASIFIER; 2- MAIN PLASMA TORCH; 3- ADDITIONAL PLASMA TORCH (H2O, CO2); 4- ADDITIONAL PLASMA TORCH;5- FEEDER; 6- SLAG REMOVAL; 7- GAS DUCT; 8- AFTERBURNER; 9- TORCH ON DUTY; 10- CYCLONE; 11- GAS ANALYZER;12- SPRAYING TOWER; 13- PACKED TOWER; 14- STACK; 15- FAN.

9

IEE RAS AIR PLASMA GASIFIER

1- shaft gasifier2- main plasma torch3,4- additional plasma torches

5- feeder6- slag removal7- syngas outlet

Zone Name Main processes

I Storage Heat up, slow evaporation

II Evaporation Intensive evaporation

III Pyrolysis Extraction of volatile matters (CO, CO2, CnHm, H2O)

IV Active

Exothermic reactions2 C + O2 → 2 COCnH2×m + (n+0,5×m) O2 → n CO2+m H2O2 CO + O2 → 2 CO2

V Reduction

Endothermic reactionsC + CO2 → 2 COC + H2O → CO + H2CO + H2O → CO2 + H2

VI Low rate reaction Cooling

VII Slag unloading Slag removal

AIR PLASMA GASIFICATION OF WOOD WASTE Period of time 1 2

Parameter Units Exp. Calc. Exp. Calc.Process temperature °C 1450-1600 1227 1300-1600 1227Energy consumption MJ/kg 2,24 2,12 3,17 3,2Syngas yield Nm3/kg 2,46 2,35 2,47 2,14

Syngas composition

H2

% vol.

28,20 24,46 31,68 31,7CO 26,97 29,76 26,11 35,5CO2 6,78 5,8 7,39 3,6N2 35,66 35,89 32,49 25,8H2O 2,13 3,64 2,06 3,09O2 0,26 — 0,27 —Ar — 0,42 — 0,28H2S — 0,03 — 0,03

Syngas LHV MJ/Nm3 5,9 5,87 6,151 7,2Condensate yield g/kg 153,2 160,2 111,3 81,7Air specific flow rate kg/kg 1,33 1,32 1,2 0,85Capacity kg/hr 114,7 75,6

AIR PLASMA GASIFICATION OF BITUMINOUS COAL NAME OF INDICES UNITS VALUE

Plasma generators total electrical power kW 58.7Average temperature on the reactor’s axis °C 1110Capacity on coal kg/hr 33.5Specific output on produced gas m3/kg 3.4Calorific value of the produced gas MJ/m3 4.7

Syngas composition

H2

% vol.

20.5CO 22.9N2 46.7O2 0.2CO2 7.4H2O 1.6Other 0.7

Conversion levelOn carbon

%

75.6On hydrogen 92.7

EfficiencyChemical 83.9Thermal 82.6

STEAM-AIR/CO2 PLASMA GASIFICATION OF MIXED FUEL.CONDITIONS FOR THERMODYNAMIC ESTIMATION

Temperature 1500 K, atmosphere pressure (101,325 кПа)

Chemical element

Usedcar tires

Brown coal

Mixed fuelUsed car tires – 30 % wt,

brown coal – 70 % wtC 60,16 26,99 36,94H 5,66 4,48 4,83O 10,74 52,92 40,27N 0,77 0,43 0,53Fe 18,3 - 5,49S 4,37 - 1,31Si - 15,19 10,63Total 100 100 100

Elementary fuel composition (as received basis) Gasifying agent compositions

Substance Gasifying agent 1 (Steam : air = 5:1)

Gasifying agent 2 (Steam : carbon

dioxide =1:1)

N2 12,58 -O2 3,86 -Ar 0,22 -CO2 0,01 50H2O 83,33 50Total 100 100

Ash of brown coal =SiO2 (cristobalite)Ash of used car tires =FeOx (ferrous oxide, iron oxide)

0 2 4 6 8 100

10

20

30

40

50

60

70

80

mol

%

Specific consumption of gasifying agent, kg/kg of feedstock

H2 CO N2 CO2 H2S H2O graphite SiO2 Fe FeO FexC

Product composition for Steam-air plasma gasification of mixedfuel (Used car tires – 30 % wt, brown coal – 70 % wt)

0 1 20

2

4

6

8

0 2 4 6 8 100

10

20

30

40

50

60 H2 CO N2 CO2 H2S CH4 SO2 H2O graphite SiO2 Fe FeO FexC

mol

%

Specific consumption of gasifying agent, kg/kg of feedstock

Product composition for Steam-CO2 plasma gasificationof mixed fuel (Used car tires – 30 % wt, brown coal – 70 % wt)

0 10

5

10

15

0 2 4 6 8 100

5

10

15

20

25

30M

J/kg

Specific consumption of gasifying agent, kg/kg of feedstock

STEAM-AIR plasma STEAM-CO2 plasma

STEAM-AIR/CO2 PLASMA GASIFICATION OF MIXED FUEL. PLASMA ENTHALPY

Plasma torch energy parameters:

(Steam : AIR = 5:1) — 12.5 MJ/kg

(Steam : CO2 =1:1) — 12.4 MJ/kg

ESTIMATION RESULTS ON STEAM-AIR AND STEAM- CARBON DIOXIDE GASIFICATION OF MIXED FUEL Parameters Unit H2O:Air H2O:CO2Enthalpy of plasma MJ/kg 11.71 11.90Mass balance Raw materials

kg/kg of mixed fuel

1.00 1.00Air 0.12 -Steam 0.58 0.35Carbon dioxide - 0.35Syngas 1.12 1.24Condensed water 0.28 0.18Ash 0.30 0.28

Energy balance LHV of the raw materials

MJ/kg of mixed fuel

13.25 13.25Plasma 8.20 8.33Inlet sum 21.45 21.58Chemical energy of the syngas 17.45 17.94Heat energy of the syngas 2.85 2.78Heat energy of condensed water 0.75 0.48Heat energy of ash 0.40 0.38Total yield 21.45 21.58

Syngas Composition H2

% vol

44.32 39.96CO 29.49 42.05N2 3.68 0.23CO2 4.49 4.98Ar 0.04 -H2S 0.44 0.47COS 0.01 0.02H2O 17.53 12.29

LHV of the dry syngas MJ/Nm3 9.56 10.16

THANK YOU FOR YOUR ATTENTION!