Non-catalytic plasma-arc reforming process of methane with carbon dioxide for hydrogen production

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NON-CATALYTIC PLASMA-ARC

REFORMING OF NATURAL GAS WITH

CARBON DIOXIDE

Author:

Author: Mr. GW BASSONMr. GW BASSON Co-author:

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Introduction

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Order

• Background

• Process Description

– Plasma-arc Reformer

– Production of Synthesis Gas – Production of Hydrogen

• Techno-economic Evaluation

• Comparison with SMR

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Background

• Current Technologies

– Catalytic Steam Methane Reforming

CH4 + H2O → CO + 3H2 ∆H0298K = +206 kJ/mol

CO + H2O → CO2 + H2 ∆H0298K = -41 kJ/mol

– Catalytic Dry Methane Reforming

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Background

continuedcontinued

• Plasma-arc Reforming

– Advantages

• High Temperature and Power Densities • No Catalyst is needed for Reforming

• High Chemical Reaction Rates (up to 100%) • Overall Efficiency of ~65%

• CO2 instead of Steam as the Oxidizing Agent

• Production Cost Competitive with SMR

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Background

• Nuclear Synthesis Gas & H

₂

Production

– ~30 Countries uses Nuclear Energy – Steam Methane Reforming Considered – High Temperature Gas Reactors (950°C) – Safety Regulations more stringent

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Process Description

• Plasma-arc Reformer – Conversion of SASOL

GAS to Synthesis Gas – Operation Conditions • Potential – 6.6 kV • Current – 1.2 kA • Power – 8 MW • Lifetime – 800-1000 h • Efficiency – 80-90% • Temperature – 2000-5000°C

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Process Description

• Assumptions

– CH4 and CO2 inlet Temperature - 25°C

– Flow Rate to Plasma-arc Reformer – 4000 Nm3/h

– Thermal Efficiency – 88% – Conversion Rate – 95%

– Plasma-arc Reformer Capacity – 8 MW – PBMR produces He at 950°C at 160 kg/s

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Process Description

• Plasma-arc Synthesis Gas

Production

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Process Description

– Process Two → CO2 & H2O as Oxidizing

Agents

η

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Process Description

• Plasma-arc Hydrogen Gas

Production

– Process Three → Electrical Energy

η

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Techno-economic Evaluation

• Assumptions

– Higher Heating Value CH4 – 36.4 MJ/Nm3

– CH4 cost - $6 per GJ

– CO2 cost - $5 per ton

– Electricity - $0.045 per kWh – Plant Lifetime – 20 years – Discount rate – 9% per year – Inflation rate – 5% per year

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Techno-economic Evaluation

continued

• Assumptions for Sensitivity

Evaluation

– Variation of CH4 between $3 to $10 per GJ

– Variation of CO2 between $0 to $20 per ton

– Variation of Electricity between $0.03 to $0.1 per kWh

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Techno-Economic Evaluation

continued

• Techno-economic Evaluation for Synthesis Gas

Production

– Process One

• Capital Investment → $90 397 381

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Techno-Economic Evaluation

continued

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Techno-Economic Evaluation

continued

Selling Price

(per GJ) NPV (years)PBP ROI IRR

$11 $41.47 million 7.7 20.3% 12.2% $12 $196.33 million 4.2 41.8% 23.5% $13 $351.19 million 2.9 63.2% 34.3%

Table 1:

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Techno-Economic Evaluation

continued continued – Process Two • Capital Investment → $93 456 159

H₂/CO Ratio Synthesis Gas_{Flow Rate} (Nm3_/year) Production Cost (per GJ) (per kg) 1.0 1 435 million $9.63 $0.17 1.5 1 435 million $9.56 $0.20 2.0 1 435 million $9.52 $0.23 Table 2:

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Techno-Economic Evaluation

continued

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Techno-Economic Evaluation

continued

Selling Price

$11 $2.19 million 9.7 14.8% 9.2%

$12 $153.08 million 4.9 34.8% 19.9%

$13 $303.97 million 3.3 54.8% 30.1%

Table 3:

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Techno-Economic Evaluation

continued continued

– Process Three

• Capital Investment → $244 742 652

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Techno-Economic Evaluation

continued

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Techno-Economic Evaluation

continued

Selling Price

$17 $61.21 million 8.7 17.7% 10.6%

$18 $192.90 million 6.8 23.9% 14.0%

$19 $324.60 million 5.6 30.2% 17.3%

$20 $456.30 million 4.8 36.4% 20.6%

Table 4:

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Comparison with SMR

• Steam methane reforming*

– Capacity → 250 000 Nm3/h

– Methane Cost → $8 per GJ – Production Cost → $12.70 per GJ – Total Capital Investment → $221.6 million

• Steam methane reforming with Carbon Capture*

– Production Cost → $14.77 per GJ – Total Capital Investment → $252.6 million

*(Mueller-Langer, F., Tzimas, E., Kaltchmitt, M. & Peteves, S., 2007, “Techno-economic

($14.25 per GJ) ($245 million)

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Conclusion

• CH

₄

and Electrical Costs have Major

impact on Production of Synthesis and

H

2

Gas