Cryogenic CO 2H 2 S capture technologies for

Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing Mehdi Panahi Trial Lecture December 1 st, 2011 Trondheim M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 1/41

Outline 1. Introduction 2. 2. Cryogenic technologies - Ryan Holmes method - Controlled freeze zone (CFZ) method - Cryocell method - Sprex method - Twister technology 3. Conclusions M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 2/41

Outline 1. Introduction 2. 2. Cryogenic technologies - Ryan Holmes method - Controlled freeze zone (CFZ) method - Cryocell method - Sprex method - Twister technology 3. Conclusions M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 3/41

CO 2 effect on Global warming Green house gases cause global warming: CO 2, the major one World energy demand is increasing • more fossil fuels • 130% rise in CO 2 emissions by 2050 • rise in global average temperature by 6°C Intergovernmental Panel on Climate Change (IPCC): “Emissions must be reduced by 50% to 85% by 2050 if global warming is to be confined to between 2°C to 2. 4°C” M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 4/41

CO 2 emission from gas processing plants Associated CO 2 with natural gas is one of the sources of global CO 2 emissions CO 2 content in natural gas varies between 2 -65% and in some reserves is even more! Increasing demand for natural gas has made reserves with high CO 2 content economically H 2 S is often present with CO 2 in natural gas reserves M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 5/41

Definitions and Spec in gas processing plants Natural gas containing H 2 S > 4 ppm is called “sour gas” Natural gas containing acidic gases like CO 2/H 2 S is called “acid gas” To produce “sweet gas”, CO 2 and H 2 S (for technical and environmental reasons) must be removed and stored Specs. for natural gas pipelines: CO 2: ≤ 2 -4 mol% (varies by the country) H 2 S: ≤ 4 ppm Specs. of natural gas for LNG plants: CO 2: < 50 ppm H 2 S: < 4 ppm M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 6/41

High acid gas content natural gas reserves Most high CO 2 natural gas resources are located in SE Asia, NW Australia, Central USA, North Africa and Middle East It is estimated 1/5 -1/3 of global natural gas resources have significant amounts of CO 2 and H 2 S Natuna gas field in Indonesia, the largest high CO 2 reserve: (>70%v) La. Barge gas field (65% CO 2) in SW Wyoming (USA), discovered in 1963, production delayed until 1986 because of high CO 2 concentration M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 7/41

Different (old/new) Technologies for CO 2/H 2 S removal Adsorption (chemical, C / physical, P) Activated carbon (C), Chemsweet (C), Molecular sieves (P), Zinc oxide (C) Absorption (mostly chemical) ADIP, Alkazid, Amisol, Benfield, Catacarb, CNG (P), Estasolvan, Flexsorb SE, Flour Econamine, Flour solvent, Giammarco-Vetrocoke, MEA, MDEA, Purisol (P), Rectisol (P), Seaboard, Selexol (P), Sepasolv MPE (P), SNPA-DEA, Stretford, Sulfiban, Sulfinol, Tripotassium Phosphate, Vaccum Carbonate, Zinc oxide Cryogenic distillation Controlled Freeze Zone (CFZ), Ryan Holmes, Cryocell, Sprex, Twister Membrane M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 8/41

Applications of different technologies in gas processing plants for removing of acid gases Adsorption Suitable for reducing CO 2 content from 3% to 0. 5% Not applicable for high CO 2 concentration streams since it needs frequent regeneration of solid bed Absorption Suitable for low pressure streams with CO 2 content of 3 -25% This method is the conventional method, which is widely used in natural gas processing industries Not suitable for very high CO 2 concentration streams due to large solvent recirculation and consequently large heat duty in the stripper for solvent regeneration M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 9/41

Applications of different technologies in gas processing plants for removing of acid gases Membrane Flexible for different CO 2 concentrations, but maintaining high performance of membrane in presence of varying contaminants of natural gas stream is a challenge Traditional technologies: - remove acid gases at near atmospheric pressures, - required significant amount of energy to compress acid gases for re-injection for Enhanced Oil Recovery (EOR) Cryogenic distillation Suitable for removing high CO 2/H 2 S contents from natural gas streams especially for offshore applications M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 10/41

Outline 1. Introduction 2. 2. Cryogenic technologies - Ryan Holmes method - Controlled freeze zone (CFZ) method - Cryocell method - Sprex method - Twister technology 3. Conclusions M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 11/41

Phase diagram for CO 2/CH 4 in 650 Psia (44 bar) Point 1: Feed Target: Feed: Chilling the feed 50% CH 4/50% CO 2 -8 (-22°C) Liquid: 18% CH 4 Solidification point of CO 2 Point 2: reaching the VL zone Point 3: Point 4: (-62°C) natural gas product with 1% CO 2 Vapor: 72% CH 4 Vapor: 85% CH 4 Achieving natural gas with CH 4 purity of >85% is not possible in one conventional distillation column Figure from: H. G. Donnelly and D. L. Katz, Phase equilibria in the carbon dioxide-methane system, I&EC, 46 (1954), 3, 511 -517 M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 12/41

Outline 1. Introduction 2. 2. Cryogenic technologies - Ryan Holmes method - Controlled freeze zone (CFZ) method - Cryocell method - Sprex method - Twister technology 3. Conclusions M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 13/41

Ryan Holmes method Invented by Arthur S. Holmes and James S. Ryan at Koch Process Systems, US in 1982 Agent should have a freezing temp. below condenser Temp. Idea: Adding a solids-preventing agent e. g. NGL, to the solids potential zone of cryogenic distillation column Pre-cooler By adding sufficiently agent, the liquid composition is moved away from the freezing point Cooling to cryogenic temperatures This method is commonly used in gas processing plants Suitable for offshore applications? The Figure from: A. S. Holmes, J. M. Ryan, Cryogenic distillation separation of acid gases from methane, US patent, 1982 M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 14/41

Outline 1. Introduction 2. 2. Cryogenic technologies - Ryan Holmes method - Controlled freeze zone (CFZ) method - Cryocell method - Sprex method - Twister technology 3. Conclusions M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 15/41

Controlled Freeze Zone method (CFZTM) CFZTM method: invented at Exxon production research in 1983 patented in 1985 First pilot plant (the picture in the right) at Exxon’s Clear Lake Gas plant in Pasedena (1987): 0. 6 MMSCFD, CO 2 (from 15% to 65%), pressure (38 -42 bar) Quality of products: while the design of top product (natural gas) specification was pipeline specs, it met LNG feed required specs! The design of methane loss at the bottom product (liquid CO 2) was 1%, but it reached 0. 5% Further studies were stopped due to collapse in oil prices Figure from: J. A. Valencia, P. S. Northorp, C. J. Mart, Controlled Freeze Zone™ Technology for enabling processing of high CO 2 and H 2 S gas reserves, Exxon. Mobil Upstream Research Company IPTC 12708 (2008) M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 16/41

Exxon’s first CFZ commercial demonstration plant at Shute Creek gas processing plant Scale up: 23 Integrated with a gas field injection Initial tests prove removal of CO 2 content from 65% down to <1000 ppm (July 2011) The tests are still being done in 20112012 Figure from: C. Condon, M. Parker, Shute Creek Gas Treating Facility Project Updates, The Wyoming Enhanced Oil Recovery Institute 5 th Annual Wyoming CO 2 Capture Conference, 13 July 2011 M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 17/41

CFZ method: thermodynamic concept 82 bar critical point of methane 42 bar critical point of CO 2 14 bar -101°C -57°C -1°C 32°C Rather than avoiding solidification, CFZ allows acid gases to freeze Operating at higher pressure than CO 2 solidification pressure (? ) Limitation of locus of the critical points Still far from the required purity for methane product Figure from the references below: H. G. Donnelly and D. L. Katz, Phase equilibria in the carbon dioxide-methane system, I&EC, 46 (1954), 3, 511 -517 and J. A. Valencia, P. S. Northorp, C. J. Mart, Controlled Freeze Zone™ Technology for enabling processing of high CO 2 and H 2 S gas reserves, Exxon. Mobil Upstream Research Company IPTC 12708 (2008) M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 18/41

CFZ distillation operation Operating the column in lower pressure than solidification pressure Operation crosses the solidification region 3 operational zones are present: 1. Stripping section (conventional distillation) 2. Solidification (controlled freeze zone, CFZ) section 3. Rectifying section (conventional distillation) Feed (mixture of CH 4 and CO 2) enters somewhere near the middle of column Reboiler duty; allowable loss of methane in CO 2 liquid bottom product Condenser temperature; required specs for purified methane M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 19/41

Liquid from the top distillation section is sprayd into the CFZ section Warmer temperature vaporize the lighter components methane product (high quality) available in high pressure Solid (pure CO 2) is formed in CFZ section and fall on the liquid layer Bottom part of CFZ is kept above solidification temperature CO 2 product (liquid)/or any other acid gas, easily to be pumped for geo-sequestration or for EOR purposes Vapor rises from the bottom distillation section to the CFZ section Colder temperature in CFZ section condenses CO 2 Figure from: B. T. Kelly, J. A. Valencia, P. S. Northorp, C. J. Mart, Controlled Freeze Zone™ for developing sour gas reserves, Energy Procedia 4 (2011), 824 -829 M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 20/41

Optimal operation of CFZ distillation Operational temperature will depend on feed composition and product specification CFZ distillation operates at constant pressure Optimized pressure of CFZ column depends on • pressure of the gas reserve, • required pressure for purified natural gas (sales spec), • geometry of the column M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 21/41

Advantages of CFZ method Suitable for high CO 2/H 2 S content natural gas reserves Separation is done in a single column, low investment cost, less challenges for offshore applications Purified natural gas product in high pressure (reduce the compressor work to export by the pipeline) Availability of CO 2/H 2 S product in liquid form, readily to be pumped for EOR, geo-sequestration purposes M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 22/41

Outline 1. Introduction 2. 2. Cryogenic technologies - Ryan Holmes method - Controlled freeze zone (CFZ) method - Cryocell method - Sprex method - Twister technology 3. Conclusions M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 23/41

Cryocell method This method was developed by Cool Energy Ltd and tested in collaboration with Shell in Australia (Perth) Idea: CO 2 sublimation point: -78. 5°C (at 1 bar) CH 4 (major component of Natural gas) sublimation point: -182°C (at 1 bar) Mixture of light hydrocarbons + CO 2 at certain T, P: Vapor-Liquid-Solid phases Solid phase: pure CO 2, Vapor/Liquid phase: CO 2 + hydrocarbons M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 24/41

Thermodynamic behavior of mixture of hydrocarbons + CO 2 1 - Mixture (feed) at pressure > 50 bar and ambient temperature 2 - Feed is cooled down to above solidification temperature of CO 2(liquid phase) before JT valve 3 - Liquid is isenthalpic flashed through a Joule-Thomson valve into a separator; solidvapor-liquid Selection of appropriate: after JT valve - pre-cooling temperature - flash pressure to minimize CO 2 content in vapor phase and methane content in liquid phase VLSE diagram for a high CO 2 content natural gas: 50% CO 2, 40% CH 4, 10% other light hydrocarbons Figure from: A. Hart and N. Gnanendran, Cryogenic CO 2 Capture in Natural Gas, Energy Procedia 1 (2009), 697 -706 M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 25/41

Different Cryocell configurations Based on natural gas composition: - high (>20%) or low (<20%) CO 2 composition - lean (recovery uneconomical) or rich of NGLs 4 process flow configurations low CO 2/lean Natural gas low CO 2/Rich Natural gas high CO 2/lean Natural gas high CO 2/Rich Natural gas M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 26/41

Cryocell process diagram for low CO 2/lean Natural gas Base case Cryocell flow diagram Figure from: A. Hart and N. Gnanendran, Cryogenic CO 2 Capture in Natural Gas, Energy Procedia 1 (2009), 697 -706 M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 27/41

Cryocell process diagram for high CO 2/Rich Natural gas Additional bulk CO 2 removal column and NGL recovery Figure from: A. Hart and N. Gnanendran, Cryogenic CO 2 Capture in Natural Gas, Energy Procedia 1 (2009), 697 -706 M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 28/41

Cryocell field results Design of demonstration plant based on scheme for low CO 2 -lean gas (2008, 2009) Removing down CO 2 content from 60% to 26%, 40% to 14%, 21% to 4% and from 13% to 3% Excellent match between tests and simulation results (Aspen Hysys + Cryo. Flash) M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 29/41

Comparison between Cryocell and Amine Absorption Amine Sale gas rate, MMSCFD Investment cost (1000 AUD), accuracy 30% 37. 7 Cryo. Cell 27. 8 38. 2 29. 6 CO 2 20% CO 2 35% 64, 359 108, 777 48, 877 67, 464 Compression Power (MW) 1. 9 3. 8 4. 3 7 Electrical load (MW) 1. 3 2. 2 0. 3 Process Heating (MW) 19 35 < 0. 1 Other advantages of Cryocell: No need for chemical solvent, no make up water, no heating system, no potential foaming Cryocell has higher maintenance costs for rotating equipment Suitable for offshore applications The data from: A. Hart and N. Gnanendran, Cryogenic CO 2 Capture in Natural Gas, Energy Procedia 1 (2009), 697 -706 M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 30/41

Outline 1. Introduction 2. 2. Cryogenic technologies - Ryan Holmes method - Controlled freeze zone (CFZ) method - Cryocell method - Sprex method - Twister technology 3. Conclusions M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 31/41

Sprex (Special pre-extraction) method Patented by IFP in 1994 and further developed in joint with TOTAL Idea: Improving the economics of amine absorption processes for removal of high H 2 S content (as high as 40%) in natural gas, where acid gases are re-injected to the reservoir Temperature of cryogenic section is -65°C High pressure liquid H 2 S ready to be pumped into the reservoir M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 32/41

Sprex (Special pre-extraction) method A temperature of -60°C to -70°C must be attained Much smaller amine absorption Figure from: To. TAL website http: //www. total. com/MEDIAS_INFOS/239/EN/sour-gas 2007. pdf? PHPSESSID=cec 2 fdfc 960710 c 595870 d 3827 bb 4269 M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 33/41

Comparison of Sprex method with Amine absorption Raw gas flowrate (MMSM 3/day) 4. 6 (165 MMSCFD) Treatment Pressure 70 bar Acid gas injection pressure 150 bar Feed gas composition H 2 S: 35%, CO 2: 7. 5%, C 1: 65. 2%, C 2+: 1% Treated gas specs H 2 S: 4 ppm, CO 2: 2% Amine+Sprex 30 Capex (MM USD) 153 128 Power consumption (MW) 52 30 Steam consumption (MW) 46 34 Sprex decreses the amine absorption size significantly The data from: F. Lallemand, F. Lecomte and C. Striecher, “Highly Sour Gas Processing, H 2 S bulk removal with the Sprex Process”, IPTC 10581, 2005 M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 34/41

Outline 1. Introduction 2. 2. Cryogenic technologies - Ryan Holmes method - Controlled freeze zone (CFZ) method - Cryocell method - Sprex method - Twister technology 3. Conclusions M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 35/41

Twister method Idea: condensation and separation in supersonic velocity (extremely short residence time), thermodynamically similar to a turbo-expander Pressure Expansion Distillation Recovery Temperature drop by transforming pressure to kinetic energy (i. e. supersonic velocity) Figure from: P. Schinkelshoek, H. D. Epsom, Supersonic gas conditioning commercialization of Twister technology, 87 th annual convention, Grapevine, Texas, USA M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 36/41

Twister method has been successfully applied for water dehydration and NGL/LPG extraction First commercial offshore application in 2004 for dehydration of 600 MMSCFD sour gas at Bintulu in Malaysia (6 Twister tubes in two parallel dehydration units) A Twister process scheme has been developed for H 2 S/CO 2 bulk removal from sour gas An amine absorption process is needed to purify the outlet of Twister to the required specs; methane recovery of 95% is expected Compact lightweight Twister can significantly decrease the size of conventional absorption processes, suitable for offshore applications M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 37/41

Outline 1. Introduction 2. 2. Cryogenic technologies - Ryan Holmes method - Controlled freeze zone (CFZ) method - Cryocell method - Sprex method - Twister technology 3. Conclusions M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 38/41

Conclusions Increasing demand for natural gas has made high acid gas reserves economically Cryogenic technologies are suitable for offshore applications processes, and operation in high pressure; - small sizes compared to conventional amine absorption - less energy requirement - separation of acid gases in liquid form and high pressure; readily to be pumped to the reservoir CFZ, Cryocell, Sprex and Twister seem to be very promising and advanced options M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 39/41

References [1] Sources of CO 2 IPCC Special Report on Carbon dioxide Capture and Storage http: //www. ipcc. ch/pdf/special-reports/srccs_chapter 2. pdf [2] J. Hao, P. A. Rice, S. A. Stern, Upgrading low-quality natural gas with H 2 S and CO 2 selective polymer membranes: Part I. Process design and economics of membrane stages without recycle streams, Journal of Membrane Science, 209, 1, 177 -206 [3] D. A. Coyle, V. Patel, Process and Pump services in the LNG industry, Proceedings of 22 nd international pump user symposium 2005, [4] http: //en. wikipedia. org/wiki/Sour_gas [5] WFJ Burgers, PS Northrop, HS Kheshgi, JA Valencia, Worldwide development potential for sour gas, Energy Procedia, 4 (2011), 2178– 2184 [6] H. J. Herzog and E. M. Drake, Carbon dioxide recovery and disposal from large energy systems, Energy and the Environment, 12 (1996), 145 -166 [7] J. A. Valencia, B. K. Mentzer, Processing of High CO 2 and H 2 S Gas with Controlled Freeze Zone™ Technology, Exxon. Mobil Upstream Research Company GASEX 2008 Conference [8] http: //www. fischer-tropsch. org/DOE_reports/GRI/gri-86_0009 -1/86_00091, %20 Part%204, %20 Pages%20298%20 -%20409. pdf [9] E. Keskes, C. S. Adjiman, A. Galindo, and G. Jackson, a physical absorption process for the capture of CO 2 from CO 2 -rich natural gas streams, Chemical Engineering Department, Imperial College London, http: //www. geos. ed. ac. uk/ccs/Publications/Keskes. pdf M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 40/41

References [10] H. G. Donnelly and D. L. Katz, Phase equilibria in the carbon dioxide-methane system, I&EC, 46 (1954), 3, 511 -517 [11] J. A. Valencia, P. S. Northorp, C. J. Mart, Controlled Freeze Zone™ Technology for enabling processing of high CO 2 and H 2 S gas reserves, Exxon. Mobil Upstream Research Company IPTC 12708 (2008) [12] B. T. Kelly, J. A. Valencia, P. S. Northorp, C. J. Mart, Controlled Freeze Zone™ for developing sour gas reserves, Energy Procedia 4 (2011), 824 -829 [13] C. Condon, M. Parker, Shute Creek Gas Treating Facility Project Updates, The Wyoming Enhanced Oil Recovery Institute 5 th Annual Wyoming CO 2 Capture Conference, 13 July 2011 [14] A. Hart and N. Gnanendran, Cryogenic CO 2 Capture in Natural Gas, Energy Procedia 1 (2009), 697706 [15] P. Schinkelshoek, H. D. Epsom, Supersonic gas conditioning commercialization of Twister technology, 87 th annual convention, Grapevine, Texas, 2008 [16] P. Schinkelshoek, H. D. Epsom, Supersonic gas conditioning for NGL recovery, offshore technology conference, Houston, 2008 [17] A. S. Holmes, J. M. Ryan, Cryogenic distillation separation of acid gases from methane, US patent, 1982 [18] http: //www. total. com/MEDIAS_INFOS/239/EN/sour-gas 2007. pdf? PHPSESSID=cec 2 fdfc 960710 c 595870 d 3827 bb 4269 M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 41/41

Thank you for your attention! M. Panahi ’Cryogenic CO 2/H 2 S capture technologies for remote natural gas processing’ 42/41