Intensification. Packed Beds for Processing Associated and Stranded Gas

Transcription

1 Intensification Packed Beds for Processing Associated and Stranded Gas Jonathan Lee, Chukwuma Anyigor School of Chemical Engineering and Advanced Materials Newcastle University.

2 Talk Outline Associated and Stranded Gas Options for Stranded Gas Gas Processing Plant Process Intensification for Stranded Gas

3 FPSO Shell Prelude

4 Gas Abundant Reserve - (161 x m 3 ) Low Carbon fuel (compared to coal/oil) Expensive to transport Typically contains: - C 1 C 6 hydrocarbons - acid gases (H 2 S and CO 2 ) - water - nitrogen and trace impurities 40-60% of the world s natural gas is stranded gas.

5 Associated Gas In billion m 3 of associated gas were flared 1. Equivalent to 25% of United States and 30% of EU gas consumption. oil field Uses could include - Power generation - Enhanced Oil Recovery - Petrochemicals Associated Gas

6 Stranded Gas - I Gas that has been produced and processed but is geographically isolated from a market

7 Stranded Gas - II Sokoto Embayment Trans-Saharan gas pipeline Chad Basin Bida Basin Benue Trough Apambra Basin 100 km

8 Options for Stranded Gas Gas pipe 2-4 million dollars per mile Pipeline Liquified Natural Gas Remote Gas Supply Gas to Liquid Gas to Wire Compressed Natural Gas Major Gas Market Gas to Solids Adapted from Wood, Ref 2.

9 Options for Stranded Gas Khalilpour 3 considered three options: Liquified natural gas (LNG) Compressed natural gas (CNG) Gas to liquids (GTL) Historical data for capital and operating costs were used. Assumption was made that pipeline specification gas was available at market price. Oil price and gas price treated as ranged, random variables.

10 Distance to market (nautical miles) Options for Stranded Gas Can Process Intensification move any of these boundaries? Liquified Natural Gas (LNG) Gas To Liquid (GTL) Compressed Natural Gas (CNG) Reservoir Recoverable Feed Gas Capacity (cubic feet x ) 1 nautical mile = 1.85 km 1 x ft 3 = 28.3 x 10 9 m 3

11 Gas Processing Absorption processes Pressure swing adsorption Cryogenic Acid distillation gas Absorption water using glycol Membrane separation Pressure swing adsorption Adsorption Gas from well Acid Gas Removal Gas Dehydration Mercury Removal Cryogenic nitrogen distillation Pressure swing adsorption Turbo-expander and demethanizer Sales Gas NGL Recovery Nitrogen Rejection NGL liquids

12 Gas Processing All the options for stranded gas involve some processing Pipeline: All LNG: All CNG: All Gas to wire: acid gas removal, mercury removal Gas to liquid: acid gas removal, mercury removal Gas to solid: acid gas removal, mercury removal, NGL recovery.

13 Lean amine Absorber Regenerator Acid Gas Removal Using Amines Sweet gas Acid gas Sour gas 7000 kpa Sweet gas Rich amine 600 kpa LP steam

14 Intensified Adsorber Gas field producing 1.4 billion cubic meters per year (at STP). Reduce the sulfur content to pipeline spec of 10 ppm(molar). Rich amine loading of 0.4 mol CO2 per mol amine. 30 mass% amine solution. The P in the column and rotating packed bed are the same. e = 97%, a = 250 m 2 m -3 Mass transfer coefficient (K G a) in the packed column is 0.02 s -1 Mass transfer coefficient (K G a) in the RPB from the data of Jassim 4

15 Absorber Volume (m 3 ) Rotating Packed Bed Power (MW) Intensified Adsorber Rotating Packed Bed Acid gas content (mol%) Capital cost savings have to offset the added operating cost of the RPB. Use higher concentration amine solutions in the RPB 0

16 Gas to Liquid (GTL) Syngas to dimethyl ether Transported using LPG infrastructure Desulphurized natural gas Reformer Syngas Fischer Tropsch Transported using liquid fuel infrastructue

17 Intensified GTL combustion catalyst fuel gas + air hydrocarbon + steam reforming catalyst micro channel reformer L H» mm flue gas syngas cooling water syngas FT catalyst micro channel Fischer Tropsch reactor steam liquid fuels Intensification of the heat transfer process leads to compact reactors Technology commercialized by Velocys and CompactGTL

18 Gas to Solids Liquified Natural Gas Compressed Natural Gas Gas Hydrates Temperature -162 C ambient -10 C Pressure 1 bar 206 bar 1 bar Gas content of 1 m 3 at STP 600 m 3 200m 3 160m 3 Water molecules hydrogen bonded in a cage around a gas molecule Gas Hydrate

19 Gas to Solids Windmeier and Oellrich 5 Water + surfactant gas 10 C, bar Process is thermodynamically driven by pressure. Rate of hydrate formation is thought to be mass transfer controlled and could be intensified.

20 Conclusions Utilizing stranded gas is a complex problem with many technical solutions Feasible options for stranded/associated gas need to be evaluated and niches for the application of Process Intensification identified. Process flow rates are large even for small fields. It is an area with potential for process intensification.

21 Thank you for listening Any Questions?

22 References Wood D, Mokhatab S, 2008, Gas monetiziation technologies remain tantalizingly on the brink, World Oil, 229, Khalilpour R, Karimi I A, 2012, Evaluation of utilization alternatives for stranded natural gas, Energy, 40, Jassim M, Rochelle G, Eimer D, Ramshaw C, 2007, Carbon Dioxide Adsorption and Desorption in Aqueous Monoethanolamine Solutions in a Rotating Packed Bed, Ind.Eng.Chem.Res., 46, Windmeier C, Oellrich L R, 2014, Visual observation of methane hydrate formation and dissociation process, Chemical Engineering Science, 109,