Articles & Press Releases

Pipeline Gas Sales from Billing Montana Landfill

A high-BTU gas project is operating to provide pipeline gas from the City of Billings landfill.  The state of the art facility is noted for the minimal process steps, elimination of pretreatment and the removal of N2 contamination.

In the delivery of feed gas at up to 2400 SCFM the raw gas is compressed to 110 psig and routed to two stages of Guild Molecular Gate PSA systems with pipeline quality sales gas delivered at 90 psig.  In the first stage water vapor, VOC’s, H2S, siloxanes and CO2 are adsorbed and removed.  Heavy impurities and VOC’s are non-detectable in the product from the first stage and CO2 is removed to less than 1%.  The resulting product gas is sent to a second stage unit that removes the N2 and a portion of the O2 and produces pipeline quality product.  Since this tail gas stream contains methane and has been previously scrubbed of undesirable impurities in the first stage PSA it is a high quality fuel and used in a genset to provide much of the power demand of the facility. 

The two stage approach allows for automatic purity control and independent adjustment of each stage to manage the unavoidable variations in the feed gas composition.

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Upgrading Wastewater Digester Gas for the San Antonio Water System (SAWS)

The largest USA wastewater treatment plant (WWTP) digester gas purifier is operating for the City of San Antonio.  Guild Associates, Inc provided the system to upgrade 1,300 standard cubic feet per minute (SCFM) of raw digester gas from 60 percent methane to pipeline quality gas in a single step.

The Guild equipment was provided to Ameresco, who owns as well as designed, engineered, permitted, constructed, operates, manages and maintains the gas conditioning and distribution facility and the pipelines necessary to transfer and sell the gas to commercial natural gas pipelines. “This is the culmination of a tremendous amount of hard work and ingenuity, along with a great partnership with SAWS, in order to implement this groundbreaking ‘renewable resource’ project,” said Michel T. Bakas, Ameresco’s Vice President of Renewable Energy. “This is an exciting project for the partners.”

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EPA Releases Report on Upgrading Coal Mine Methane to Pipeline Quality Natural Gas

The EPA, through its Coal Mine Methane Outreach Program, has released a report on upgrading contaminated coal mine gases to pipeline quality. With twelve systems upgrading gas from coal mines the Molecular Gate technology from Guild Associates, Inc. is the leading route to producing pipeline quality natural gas from this resource.

In upgrading this contaminated gas the Molecular Gate process operates at a moderate pressure of about 100 psig and produces pipeline quality sales gas at 90 psig. Coal mine gases are commonly contaminated with both CO2 and N2 and the Molecular Gate process removes both impurities in a single step and thus avoids separate amine processing for CO2 removal and associated operating difficulties and capital and operating cost.

Guild’s first Molecular Gate unit in this service started operation in 2003 with the remaining 11 units provided since that date.


... Download PDF Document:
EPA Publication 430-97-012
Upgrading Drained Coal Mine Methane to Pipeline Quality: A Report on the Commercial Status of System Suppliers

Intrepid Technologies System Produces Pipeline Quality Gas from Digester Gas

By utilizing the Guild PSA System, Intrepid Technologies is now able to produce a valuable natural gas product while benefiting the environment by reducing the production of greenhouse gases.

Intrepid Technologies, LLC., has been operating the first of two PSA Systems supplied by Guild Associates for upgrading biogas at their Whitesides Digester Facility in Idaho. The operation, in the initial one-year time period, has shown the production of pipeline quality gas that meets or exceeds the required specifications.

"We are pleased that this system enabled us to bring the gas to pipeline purity and allow the delivery to an interstate pipeline," said Brad Frazee, Vice-President biomethane operations for Intrepid. “We look forward to future digesters and working with Guild on future projects”.

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Developments in Gas Separation

Guild Associates is pleased to announce the results from its comprehensive field study to upgrade biogas to pipeline quality in its PSA system. Upgrading biogas generated from livestock manure and supplemental feedstocks is growing in popularity as operators realize the potential revenues from the sale of their gas to the pipeline. Guild’s system has been proven to remove contaminants, water, H2S and CO2 in a single, self-contained unit, making it simple and inexpensive for the operator to achieve high purity pipeline-quality natural gas.

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