Activated Carbon for Biogas Purification and Upgrading

Biogas has completed its transition from waste byproduct to renewable energy commodity. Whether produced from municipal digesters, landfill cells, or agricultural fermenters, raw biogas is contaminated with hydrogen sulfide, siloxanes, moisture, and trace halocarbons that destroy engines, foul catalysts, and block grid injection.

The economic value of biogas is not determined at the digester outlet; it is determined at the point of use, after purification has protected the CHP engine, the upgrading membrane, or the pipeline meter. PureStar treats biogas upgrading as asset protection and energy yield optimization.

The Challenge & PureStar Approach

Biogas composition is far more variable than standard design assumptions suggest.

Anaerobic digesters can swing from hundreds to thousands of ppm $H_2S$ depending on feedstock and temperature. Siloxane levels correlate with landfill age and digester substrate type. Many facilities operate in humid or tropical climates where conventional activated carbon loses capacity as relative humidity climbs.

The Operational Impact: The result is premature bed replacement, unplanned engine overhauls, and lost revenue from rejected gas.

The PureStar Solution

PureStar's biogas grades are distinguished by humidity resilience and multi-contaminant architecture:

• • Humidity Resilience: We employ moisture-resistant binders and pore designs that maintain $H_2S$ removal efficiency even when relative humidity exceeds typical operating ranges.

  • Multi-Contaminant Control: By tailoring macropore and mesopore distributions, a single bed can simultaneously accommodate small $H_2S$ molecules and larger siloxane species, delivering multi-impurity control without forcing operators into costly multi-stage trains.