Biogas Scrubbers and Purification Systems
H2S removal and gas treatment for cogeneration and upgrading
Biogas produced by the anaerobic digestion of agricultural biomass, livestock effluent or organic waste contains, in addition to methane and CO2, a range of unwanted compounds that can impair the proper operation of cogeneration units and significantly shorten the service life of mechanical components. The main one is hydrogen sulfide (H2S), a corrosive gas that attacks metal surfaces, degrades lubricants and accelerates wear in engine combustion chambers. Even relatively low H2S concentrations—above 200–500 ppm, depending on the engine type—make purification necessary before the biogas is fed to the cogeneration unit. Other impurities, such as siloxanes, ammonia and fine particulates, can also cause deposits and damage mechanical components, requiring integrated treatment systems.
LAI Srl designs biogas scrubbing and purification systems using wet scrubber technology to effectively remove H2S, reduce the gas’s relative humidity and capture other impurities. Our scrubbers are sized according to the customer’s biogas composition, volumetric flow rate and inlet H2S concentration, with a typical removal target of over 95%. The structure is made of AISI 304 or 316 stainless steel, with high-specific-surface structured packing to maximise contact between the gas and scrubbing liquid.
The liquid recirculation system is operated by a centrifugal pump and an automatic pH control valve, which maintain optimum washing conditions over time without the need for frequent manual intervention.
Every treatment skid is fully pre-assembled at our workshop in Cerreto Guidi (FI), pressure-tested and delivered ready for connection.
These systems can be used as the first conditioning stage in biomethane upgrading plants—where the gas must meet the specifications for the natural gas distribution network—or as pretreatment upstream of cogeneration units, extending the interval between lubricating oil changes and reducing routine maintenance costs.
On request, our scrubbers can be combined with refrigerated dehumidification systems, activated carbon filters to remove siloxanes, continuous gas quality analyzers, and elemental sulfur recovery systems. The entire skid is controlled by LAI's automation panel, with remote supervision, configurable alarms and continuous recording of process parameters.
