Concentration of saline produced water from coalbed methane gas wells in a multiple-effect evaporator using waste heat from the gas compressor and compressor drive engine
✍ Scribed by Leon Y. Sadler; Oommen George
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 506 KB
- Volume
- 101
- Category
- Article
- ISSN
- 0011-9164
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✦ Synopsis
The use of heat of compression from the gas compressor and waste heat from the diesel compressor drive engine in a triple-effect feed forward evaporator was studied as a means of concentrating saline product:d water to facilitate its disposal. The saline water, trapped in deeply buried coal seams, must be continuously pumped from coalbed natural gas wells so tha~ the gas can desorb from the coal and make its way to the wellbore. Unlike conventional natural gas which is associated with petroleum and usually reaches the wellhead at high pressure, coalbed natural gas reaches the wellhead at low pressure, usually around 101 kPa (1 arm), and must be compressed near the well site for injection into gas transmission pipelines. The water concentration process was simulated for a typical 3.93 m3/s (500 MCF/h**), at standard conditions (101 kPa, 289K), at the gas production field in the Warrior Coal Basin of Alabama, but has application to other coalbed gas fields being brought into production throughout the world. The baseline conditions of the study were: feed water dissolved solids content: 0.25 wt% ppm (mostly NaCI); feed water flow rate: 0.84 kg of produced water per m 3 (50 Ib/MCF) of produced gas; product water dissolved solids content: saturated brine (approximately 26 wt%) at 293 K (68 F); gas pressure in/out of compressor: 101 kPa/3.35 MPa (1 arm/35 atm). The study results showed that a fuel heat input to the diesel compressor drive engine of 6.13 MW (20.9x 106Btu/h) was required. Heat transfer surface areas of 47.5, 69.1, and 71.0 m 2 (511,744, and 764 ft 2) were required in effects I, II, and III, *Corresponding author. **MCF=IO 3 standard (101 kPa and 289 K) ft 3.