DEMONSTRATION OF A LOW COST

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DEMONSTRATION OF A LOW COST 2-TOWER MICRO SCALE
N2 REJECTION SYSTEM TO UPGRADE LOW-BTU GAS
FROM STRIPPER WELLS
a JOINT PROJECT by THE KANSAS GEOLOGICAL
SURVEY (KUCR, University of Kansas) AMERICAN
ENERGIES CORPORATION (Wichita, Kansas)
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Low BTU Natural Gas Resource Base

• Pipeline specifications gt 950 BTU/cu ft
• Less than 950 BTU/cu ft considered as low-BTU
• U.S. natural gas reserves 204 Tcf (EIA, 2006)
• Sub quality (low BTU) Gas Reserves
• gt 2 CO2, or gt 4 N2 or inert gases
• 17.5 Tcf Mid-Continent (Hugman, 1990)
• 9 Tcf Rocky Mountain Region (Hugman, 1990)
• 33 of 1253 gas analyses in KS are low-BTU
  (Newell, 2007)
• Low BTU due to presence of N2
• 32 Tcf nationwide (17 of reserves) (Lokhandwala,
  2006)
• Significant portion located in small or modest
  size fields
• Great majority in Mid-Continent (Jenden, 1988)

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Low-BTU Gas Reserves in KS
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Problem Statement

• Available N2 rejection technologies
• Cryogenic Large feed volumes (gt 5 mmcfd) and
  expensive
• Conventional (3 or 4 Tower) PSA/TSA 0.5 to 20
  mmcfd
• Expensive to design and build patented
  components/processes
• N2 rejection technologies under development
• Lean Oil Absorption Membrane Separation
• Most of the nations gas production large
  fields
• Low BTU gas processed at centralized facilities
  cryogenic/PSA
• To meet long-term demand of natural gas in the US
• Small, isolated, low-BTU reserves have to be
  mobilized
• Currently SI or behind pipe lacking micro-scale
  separation plants
• REQUIRE LOW COST MICRO N2 REJECTION PLANT
• ECONOMIC at LOW VOLUME, LOW PRESSURE

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Project Objectives

• Goals
• Design, build, optimize 2-Tower Micro-Scale N2
  rejection plant
• Using Pressure Swing Adsorption (PSA)
• Patent free off-shelf, non-proprietary
  components
• Conventional plants use proprietary components
  and processes
• Economic at low feed volumes - lt 200 mcfd
  (shallow/small fields)
• Estimate well deliverability and decline to
  size the plant
• Small field size affects production decline
• User friendly techniques commonly available
  software/freeware
• Analyses Wireline logs, 4-point test, and
  production decline
• Disseminate LESSONS LEARNED to stripper well
  community
• Technology Transfer Workshops Publications
• Maps showing distribution of N2 rich low-BTU
  reserves in KS

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2-Tower Micro-scale N2 Rejection Plant
Diam. 4 ft, Ht. 8 ft Feed 150
mcfd Composition 70 CH4, 25 N2, 3 HHC, 2
inert Sales Stream 100 mcfd, lt4 N2, 975
BTU/cu ft Vent 5 CH4
Adsorbent Activated Carbon made from coconut
husks
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Palletized Activated Carbon

• Made from coconut husks
• Large surface area
• 300 to 4000 m2/g
• Pore size diameter 10 to 25 Angstroms
• Adsorbs larger molecules
• CH4, H2S, CO2, H2O
• Vents smaller molecules
• N2, He, O2, H2, CO
• Regenerate adsorbed CH4
• Under vacuum

Activated Carbon from coconut Husk
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Proposed Technology vs. Conventional

• Conventional Commercial PSA Plants patented
  parts/processes
• 3 to 4 Towers requires professional design
  (1/3rd cost mark-up)
• Patented adsorption beds
• Patented purge cycles reduces pressure shock on
  beds
• Surge towers uniform composition of sales gas
• Economic feed volumes 500 mcfd to 20 mmcfd
• Proposed Micro-scale Plant non proprietary
  parts/processes
• 2 Towers Easy to design and build (lt10 moving
  parts)
• Use readily available palletized activated carbon
  for adsorption
• Carry out pressure equalization by pause using
  vent gas
• Discharge gas accumulator uniform composition
  of sales gas
• Economic feed volumes 40 to 200 mcfd (lt100 psi)
• Enhances bed life and reduces dust emission
  (compressor fowl up)
• Additional Differences
• Micro plant Modular Scalable, Operate in
  remote locations

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Conventional PSA Plants 3 4 Towers
Surge Chambers

• Each tower in different cycle
• Adsorption
• Desorption
• Pressure up slowly
• Slowly going to vacuum

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Cycle Time Optimization Micro Plant

• Basic PSA Principle TIME TESTED (IT WORKS)
• PSA used many different applications
• CH4 can be adsorbed in a bed of activated carbon
• Critical Question How to optimize a micro-scale
  plant ?
• Main Goal Shortest cycle time for max CH4
  recovery
• Selectively vary input parameters
• Inflow rates
• Cycle time
• Adsorbent quality
• Measure effect on
• CH4 recovery and breakthrough
• Bed economics degradation, compaction,
  heaving
• Operation costs

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Elmdale Field, Chase County, KS

• Other N2 Rejection Plants in KS
• Cryogenic plant (McCoy Pet)
• Feed volume 5 mmscfd
• Hodgeman Ness County

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Other Features Micro Plant

• Scalability
• Small, shallow, low BTU fields production
  decline
• Designed to handle varying feed - 40 mcfd to 200
  mcfd
• Skid mounted units attach/detach units to
  process high/low feed
• Operating Economics
• Initial investment 100,000 (Conventional PSA 3
  to 4 times)
• At 5/mcf, monthly income 4,500 to 11,250 (40
  to 150 mcfd)
• Building Material Carbon steel
• Instruments control panel low cost cast iron
  (rated 125 psi)
• Widespread availability easy replacement
• Patents Proposed process and components not
  covered
• Previous SWC funding None to our knowledge

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Anticipated Results Micro Plant

• Significant Production Improvement
• U.S N2 rich low-BTU reserves 32 Tcf (17)
  (Lokhandwala, 2006)
• Much of this sub quality gas trapped in
  small, isolated fields
• Proposed Micro Plant Mobilize N2 rich low-BTU
  gas
• Could add 1 Tcf to U.S. reserves (Lokhandwala,
  2006)
• Within resource reach of stripper well operators
• Reduction in Operating Costs
• Optimized, plant runs unattended 95 of time 2
  operator visits/d
• Monthly maintenance compressor and bed level
• Less than 10 moving parts (outside engine
  compressor)
• Minimal Environmental Impact
• Does not require electric power - compressor
  runs on feed gas
• Compressor engine Powers batteries to run unit
• Solar panels Power flare in vent gas line
• Vent gas has no VOCs, heavy HC, H2S, CO2, and H2O
  
• Small footprint - 400 sq ft

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Anticipated Results Micro Plant (contd)

• Commercialization Viability
• Our micro plant Simple, patent-free, off-shelf
  components
• Within resource reach of stripper well operators
• Build, design, operate on their own or with
  minimal outside help
• No waiting period for wide scale application
• Technology Transfer Workshops upon completion
• Easy to use techniques to determine well
  deliverability decline
• Step-by-step guide to scale design a
  micro-plant non-patented
• Best practices regarding optimizing plant
  performance
• Plant maintenance protocols
• Application of 2-Tower Micro-Scale N2 Rejection
  Plant
• Small, isolated N2 rich low BTU fields/stripper
  wells in US
• Low feed volumes lt 200 mcfd
• If vent gas gt 10 He compress _at_ 3000 psi for He
  plants
• At current rates value added by-product

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How does our proposed project complement SWCs
goals?

• SWC seeks to identify new technologies
• Significant production increase - domestic OG
  stripper well/field
• Significantly reduce operator costs
• Improve environmental issues
• Have broad applicability to large regions of the
  US
• Successful demonstration of our proposed project
• Mobilize an entire class of unproduced gas 1Tcf
  N2-rich low-BTU
• Unattended operation (95), lt10 moving parts,
  inexpensive spares
• No emissions of CH4, H2S, CO2, HHC, VOCs
• 100,000 investment, attractive returns,
  technology transfer
• OUR GOALS Field Demonstration Tech Transfer
• Demonstrate how stripper gas operators can build
  and operate a low-cost N2 rejection plant using
  non-patented components
• ACTIVATED-C BASED ADSORPTION WORKS NEED TO
  OPTIMIZE AT MICRO SCALES

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Benefits to AEC Stripper Well Operators

• AEC primarily owns and operates stripper wells in
  KS
• Benefits to AEC
• Produce known low-BTU reserves behind pipe
  Elmdale field
• Phase II bring online low volume, low BTU wells
  SI presently
• Neighboring high BTU fields have depleted
• Proposed 2-Tower Micro Scale Plant
• Within resource reach of stripper well operators
  such as AEC
• Technology and Financial
• However, need to develop a learning curve
• No micro scale N2 rejection plant is currently
  operating in KS
• Learn how to design, scale, build, operate, and
  optimize a micro plant
• Request SWC support to try new patent-free
  technology
• Technology transfer workshops upon completion
• Convey transfer lessons learnt to stripper well
  community