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Click to edit Master title style Cost Effective Sulfur Removal From Refinery Fuel Gas

September 28th 2011

Making our planet more productive

www.praxair.com

Raymond F. Drnevich, Vasilis Papavassiliou & John Scalise

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Cost effective non-H2S sulfur removal from refinery fuel gas

Refinery fuel gas, especially derived from a coker unit may contain 300 ­ 900 ppmv of non-H2S sulfur (COS, mercaptans, thiophenes, sulfides) SCAQMD estimates 30% of refinery sulfur emission originate from refinery gas

Refinery Gas Processor

H2S

Refinery Fuel Gas

S

Organic Sulfur Converts to H2S

Amine System

Heaters & Boilers

H2S

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The RGP Reaction System

Refinery gas + Steam

Oxygen (optional) Mixer

Differences to standard hydrotreating ­ Catalyst is a commercial structured catalyst impregnated with precious metal

Refractory Ceramic Insulation

· Substrate good to temperatures in excess of 1100 oF · Low pressure drop · Fast response time/easy control

­ Low residence time

· Results in a manageable catalyst cost

­ Operates with and without oxygen addition

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RGP Simplified Flowsheet

RFG from RGP (High H2S) Refinery Amine Treater Low Sulfur RFG

Refinery Fuel Gas from Amine treater (High non-H2S Sulfur)

Refinery Heaters & Boilers

Oxygen/Air Injection (Optional)

· Steam is used for startup

Start up Feed Preheater Feed Effluent Exchanger RGP Reactor

· Temperature control (700F) · · Olefin hydrogenation provides energy during operation Oxygen is used when olefin content is low

Steam from Refinery (start up only)

· High space-velocity precious metal catalyst

Skid mounted RGP reactor requires small footprint

· No fired heater required

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Non-H2S Sulfur Converts to H2S

Inlet 80 70 Concentration, ppm 60 50 40 30 20 10 0 Mercaptans COS/Sulfides Disulfides Thiophenes Outlet

Sulfur conversion performance over one month Space velocity 50,000hr-1 Sulfur conversion >90% Effective for all sulfur species

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RGP Benefits/Future Directions

RGP/amine ISBL cost significantly lower than alternatives

­ Capital and operating cost

­ ¼ the cost of caustic treating RGP technology can use an existing amine system RGP can enable a 90% reduction of non-H2S sulfur SOx emissions Pilot plant operating in Tonawanda since 2007

­ Simulated refinery gas ­ Fully automated operation (24/7) ­ Variable olefin composition ­ Variable sulfur composition ­ Gas Chromatography/Sulfur analyzer

Catalyst improvements Better integration with refinery processes Overcome perceived risk

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RGP for Energy Savings/CO2 Reduction

Refinery Gas Conditioning for

­ H2 production in Steam Methane Reformers ­ Electricity generation in Gas Turbines with DLN combustors

Manages surplus fuel gas issues without changing refinery processing conditions Energy savings and/or CO2 reduction project driver Allow expansion/optimization of refinery operations without penalty for increased RFG production (e.g. coker, FCC etc.)

Potential RFG Feed To SMR MMBTU/day 3,920 19,150 37,160

SMR H2 Capacity MMSCFD 10 50 100

A typical 100 MBPD refinery will reduce fuel gas consumption by 6000 to 7000 MMBtu/day when it reduces EII by 10 units.

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