Saturday, 11 February 2017

CARBON FORMATION

'Carbon Formation Depends on: - feedstock - operating conditions - catalyst Carbon Deposition Carbon Catalyst surface 1 mm (40 thou) Carbon Formation CH4 C + 2H2 (Thermal Cracking) CO + H2 C + H2O (CO Reduction) 2CO C + CO2 (CO disproportionation “Boudoua...Carbon Formation  Direction of reaction determined by process gas conditions  Generally, CO reduction and Boudouard are ...pH2 2 pCH4 10 1.0 0.1 550 600 650 700 750 800 Carbon Formation Zone No Carbon Formation Deposition rate < removal rate Dep...10 0 10 1.0 0.1 550 600 650 700 750 800 0.6 0.5 0.4 0.3 Carbon Formation Zone Temperature (°C) Proportion of tube length f...100 10 1.0 0.1 550 600 650 700 750 800 0.6 0.5 0.4 0.3 Carbon Laydown Zone 1100 1200 1300 1400 (°F) Carbon Formation - Hot...Carbon Formation C + H2O CO + H2 (CO Reduction - in reverse!) Catalyzed by OH- 800 100 10 1.0 0.1 0.6 0.5 0.4 0.3 550 600 650 700 750 Increasing Potash Content 1100 1200 1300 1400 (°F) Carbon Formation...Role of Alkali  Reduces likelihood that carbon will be formed  Enables carbon to be removed readily  Incorporation into...Fraction Along Tube Inlet Outlet Non-Alkalised Catalyst Rings Optimised Shape Inside Tube Wall Temperature 920 (1688) 820 ...Methane feed/Low heat flux Increasing Alkali Addition 0 Methane feed/High heat flux Propane, Butane feeds (S/C >4) 2-3 Pro...Feedstock Natural Gas Reforming Non- alkalised Associated Gas Ref Lightly alkalised Dual Feedstock Reforming Moderately al...Alternatives to Alkali • Precious metals can also be used instead of Ni as the catalyst – Significant higher activity and ...














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