Coal Bed Methane Water Treatment System

(CBM-WTS)

     New technology is needed to economically render coal bed methane (CBM) product water suitable for:
  • irrigation of sensitive crops,
  • application to vulnerable soils,
  • unrestricted beneficial discharge to surface waters, and
  • use of an otherwise wasted resource - groundwater.
     Drake Engineering Incorporated (DEI), a Montana-based private research and development firm subcontracted to Montana State University, is currently pilot testing an innovative process to economically and reliably treat CBM product water to achieve virtually any specified treated water quality. DEI's proprietary CBM Water Treatment System (CBM-WTS) is engineered and designed to meet a set of challenging performance requirements dictated by the unique needs of both the producers and potential consumers of treated CBM product water. This project was developed collaboratively with Montana State University with support from the Department of Energy National Petroleum Technology Office in Tulsa, Oklahoma.


CBM-WTS is designed to ensure both a broad range of applications and maximum performance flexibility.


CBM-WTS operational requirements address the challenging conditions imposed by unattended, remote operations, in a harsh environment.


CBM-WTS technology will treat water at unit costs that are extremely attractive to both water producers and consumers.

     Estimated treatment costs depend on the size of the CBM-WTS and the site-specific treatment specifications. Target unit treatment costs are less than five cents per barrel (42 gallons) for a large (1,000 gpm) system, designed to remove 50% of sodium and bicarbonate from typical CBM product water. Treatment costs include capital recovery, reagent costs, and maintenance labor.


Pilot Plant Run #1020A Results

Test Run Objective: Treat feed water that closely approximates surrogate Powder River Basin coal bed methane product water.

  1. Functional and chemical performance of CBM-WTS were verified.
  2. Pilot plant successfully treated feed water exhibiting 50 meq/l NaHCO3.
  3. Sodium concentration in feed water was reduced by 70%.
  4. Feed water SAR was reduced from 33.8 to 10.5, about 68%.
  5. Feed water pH was reduced from 8.1 to 6.1 and rebounded to above 7 after equilibration with atmosphere.
  6. Run Data Summary: analytical data for: 1) target surrogate water, 2) raw makeup water, 3) surrogate feed water and 4) mid-run CBM-WTS product water.
Table 1: Summary of Run 1020A Analytical Results
Parameter
Target
Raw
Feed
Product
pH
NA
7.8
8.1
6.1
EC (dS/m)
4.95
0.86
4.45
1.47
Ca2+ (meq/l)
2.1
4.7
0.9
1.8
Mg2+ (meq/l)
2.5
2.5
1.7
0.6
Na+ (meq/l)
46.3
0.7
38.3
11.4
Cl- (meq/l)
0.9
0.7
0.6
0.5
SO42-
0.1
1.5
1.5
2.5
HCO3- (meq/l)
51.5
5.7
49.6
10.9
SAR
30.5
0.4
33.6
10.4
  • Target = Signature of CBM product water target to be treated
  • Raw = H2O used to synthesize surrogate CBM product water for treatment, i.e., stock water supply
  • Feed = Signature of synthesized surrogate CBM product water treated
  • Product = Outflow, i.e., treated water


For additional information:

Ronald N. Drake, P.E.
Drake Engineering Incorporated
75 Lincoln Road West
Helena, MT 59602--9420
(406) 458-9288


Poster Presentation

Geochemical Constraints on Selection of CBM Product Water Management Strategies

Presented by Ron Drake (Drake Engineering Incorporated, Helena, Montana) at the 2004 Montana Soil and Water Conservation Society Annual Meeting in Billings, Montana.