Biogas Conditioning

Everyone talks about synergies. We capitalize on them!

Years of experience in plant and equipment engineering, development leader in natural gas service stations, and manufacturer of fuel vapor recovery systems – all this, taken together, has put us in a position to become, in the shortest possible time, a highly competent partner in the field of biogas conditioning plants. Based on our experience in the fields mentioned above, we offer excellent craftsmanship, reliable adherence to standards, and efficient planning. This is demonstrated in the above-average quality of our systems, which are paired with services we provide to ensure the ideal cost-benefit ratio for your biogas conditioning system. We attach particular importance to reducing ongoing operating costs. With electrical consumption at less than 0.2 kWh/Nm³, referenced to the raw gas, we set standards here.

Biogas conditioning by way of physical absorption

The biogas conditioning process developed in recent years by Schwelm Anlagentechnik GmbH represents a consistent refinement of a concept that has already established its position on the market – biogas conditioning by way of physical adsorption or physical washing (polyglycol scrubbing).

The material used to clean the biogas, i.e. to enrich the biomethane it contains, is an organic absorption agent based on polyethylene glycol. The fluid, developed especially for this process, is able to selectively remove from the raw biogas components that are undesirable in the biomethane. The absorption fluid offers excellent selectivity, especially for CO2, H2S and water. The absorption process takes place in a pressurized, packed column using the counterflow principle. Methane concentrations of 98 percent by volume can be achieved in the downstream biomethane. The absorption fluid is regenerated in a packed column, too. This is done by increasing the temperature, reducing pressure and blowing stripping air into the fluid, once again in a counterflow system. The familiar problem of methane loss through simultaneous absorption can be minimized by selecting appropriate operating parameters for the conditioning plant. Methane losses of less than 1% (referenced to the volume of methane in the raw biogas) can be guaranteed, subject to correct system operation and parameterization. The process described here has been optimized by Schwelm Anlagentechnik GmbH to the extent that operations require minimum engineering work and energy input. Our biogas conditioning plants are thus characterized by especially profitable procurement and operating costs in all areas.

Make your own comparisons!

Available at present are plants ranging in size from 200 to 700 Nm³ of product gas (biomethane).

  • Physical scrubbing process under pressure, with novel, stable scrubbing solution
  • Conditioning raw biogas to biomethane quality approved for feed-in in accordance with DVGW regulation G260
  • Pure gas quality of up to 98 percent methane by volume
  • High pure gas pre-pressure at approx. 6 bar (gauge)
  • Extremely energy-efficient operation; overall energy needs of less than 0.2 kWh/Nm³ of raw gas
  • No process heat has be applied
  • Redundant design of the compressor and pump sections
  • Low methane losses, less than 1% (referenced to the methane content in the raw biogas), for small installations methane loss is less than 0,2%
  • Virtually no methane slip (less than 0.1%)
  • Optimized, high-quality engineering based on experience in chemical plant construction
  • Autothermic waste gas scrubbing, also without requiring external process heat
  • Drying the biomethane (PSA system) to the desired dew point  before output
  • Low maintenance costs for the system as a whole

The generation of biogas through fermentation, based on renewable raw materials, has exhibited dynamic growth since 2006. Due to current market developments and thanks to the Renewable Energies Act (EEG) newly revised and passed once again in 2010, positive development potential can be expected.

As a highly competent partner adhering to industrial standards, Schwelm Anlagentechnik GmbH can handle the entire course of the project, including all the phases involved:

  • Planning
  • Basic engineering
  • Detail engineering
  • Engineering for applications for permits
  • Physical design
  • Construction and on-site assembly
  • Commissioning
  • Maintenance and repairs

Our plants are fitted exclusively with high-quality components and materials manufactured by renowned producers. Assembly and piping at our factory in Schwelm are carried out by personnel with years of experience in the field. When selecting components, particular attention is paid to energy efficiency and reliability.

Major components of the Schwelm biogas conditioning plant

  • Absorption column (to scrub the raw biogas)
  • Flash column (to recover absorbed methane)
  • Desorption column (to regenerate the absorption agent)
  • Multi-stage centrifugal pump (engineered for redundancy, to maintain circulation of the fluid)
  • Air cooler (to cool the absorption agent and remove process heat)
  • Two-stage compressor group (claw and screw compressors, partly or fully redundant if desired, to compress the raw biogas to the pressure needed for absorption)
  • Pipe bundle heat exchanger group (increasing the thermal integration of the overall process by transferring waste heat from the compressors to the absorption agent)
  • Radial blower (to inject stripping air into the desorption column)
  • System for regenerative, thermal afterburning of waste gasses from the process (in accordance with the German Air Quality Act)
  • Fully automatic, continuous absorption drying (PSA) to remove water from the biomethane
  • Optional: Biogas blower (to move the raw biogas from the fermenter into the biogas absorption unit)
  • Optional: continuous, adsorptive preliminary desulfurization (fine sulfur removal) by doped or impregnated, activated charcoal, for instance
  • Electronic measurement, regulation and control technology; all the hardware and software from a single source
  • Telecontrol and process control system for fault analysis and parameterization of every PC connected with the Internet
  • Containerized building (to house the process technology and electrical equipment) in concrete or steel; optional installation of all the machinery and electronic measurement, regulation and control technology in existing buildings