BIOGAS UPGRADING

ESI is an industry leader in delivering biogas processing solutions for a wide variety of biogas feedstocks, to remove H2S, H2O, particulates, and other impurities from raw biogas to product high-quality, medium-BTU biogas for use in electric power generation, heating, and cooling (CHP) applications.

For conversion to clean-burning, high-BTU renewable natural gas (RNG) that can be injected into natural gas pipelines and for use as vehicle fuel, biogas must be processed to more stringent purity standards. This upgrading process further refines biogas to remove carbon dioxide (CO2), hydrogen sulfide (H2S), and any other remaining trace elements.

The resulting renewable natural gas has a higher proportion of methane, making it interchangeable with conventional natural gas (NG)—and therefore a commensurate energy source in applications that demand pipeline-quality gas, including use in fuel cells for power generation and for vehicle applications.

Regardless of whether biogas will be used for power generation, heating or cooling - or will be further upgraded to RNG - impurities will need to be removed, to a greater or lesser extent, depending on the end-use/application. Even the simplest applications benefit from clean, dry gas—which delivers higher energy content and extends the life of equipment.

There are a variety of ways to address CO2 removal for you biogas upgrading system.  ESI's biogas experts will evaluate your project to determine the best method for your specific needs.

Water scrubbing
Water scrubbing is a common method for removing CO2 from the biogas stream, utilizing a cold stream of water to absorb carbon dioxide directly from the methane stream.

Amine Scubbers
Amine scrubbers deliver efficient CO2 removal by utilizing chemical absorption to remove CO2 from the biogas stream. Although amine must be dried for reuse, amine scrubbers deliver high performance with overall low power consumption.

Pressure Swing Adsorption
Pressure Swing Adsoprtion (PSA) utilizes various adsorption materials to separate mixed gases and effectively remove CO2. Pressure within the PSA vessel causes the CO2 in the biogas stream to cling to the material.

PSA processes are particularly effective for complex gas mixtures as various absorption materials can be used to capture and separate different gasses. Similar to amine scrubbers, PSA systems are highly efficient and require little electric power.

Membrane Technologies
Innovative membrane technologies can be used alone or in conjunction with other technologies to improve separation efficiency.

Cryogenic Distillation
Cryogenic distillation is the process of cooling biogas to a very low temperature, such that CO2 is liquefied and can be easily separated from the biogas stream.

Cryogenic distillation leverages the fact that carbon dioxide condenses and freezes at a higher temperature and therefore before methane does, allowing the liquid carbon dioxide to be removed.

Purified, pipeline-quality renewable natural gas (RNG), also known as Biomethane, refers to biogas that has been cleaned and conditioned to remove—or significantly reduce—non-methane elements as described above.

ESI’s superior ability to seamlessly integrate multiple technologies (electrical, mechanical, and controls) supplied by multiple different equipment vendors allows us to deliver a unified operating facility—designed to maximize facility performance, safety, and up-time.

RNG can also be used as an environmentally friendly transportation fuel, in the form of renewable compressed natural gas (CNG - also referred to as R-CNG) or liquefied natural gas (LNG).

Renewable natural gas is qualified as an advanced biofuel under the U.S. federal Renewable Fuel Standard program. ESI can assist with every aspect of your CNG project.