We thought that we would write about the biogas compressor, its purposes within an anaerobic digestion plant. Plus, design requirements and suppliers. Biogas is an environment-friendly energy source.
It is a product that is quite new and there is a growing market for the specialized corrosion resistant compressors required. The essential features sought in compressors for biogas treatment and handling are:
- dependability, and
- low running costs
- easy to service.
Compressors Designed for the Biogas Industry
There is greater sophistication in the design of modern biogas plants, now that the many benefits from anaerobic digestion are becoming better understood globally.
Rather than generate electricity for supply into a local grid, there is far more value in the biogas if it is purified (upgraded) and compressed.
The market is huge for renewable cylinder gas. The result is that many installations will need more than one biogas compressor, and we decided to make a video, to present the subject.
A low-pressure compressor is used to convey the stored biogas to the upgrading equipment. After upgrading a high-pressure compressor is required to fill the cylinders.
We invite you to watch our video about these compressors below:
Biomethane Delivery Demands High-Pressure Compression
At the high-tech end of the biogas industry are the large biogas plants which are increasingly being used to produce purified biogas at a very high quality, and that is called “biomethane”.
Methane (biomethane), does not liquefy at low pressures in the way that propane and many other hydrocarbon gases do.
This makes it necessary to compress it to higher pressures, and that makes it harder to compress.
Biomethane for grid injection needs to be compressed in a special biogas (biomethane) compressor at a pressure suitable for it to be injected into the natural gas grid.
Biogas Upgrading Provides Fuel to Compete with LPG and CNG
Biogas needs purifying before it can be used. This is usually called “upgrading” and the biogas compressor for this application is designed to raise the gas pressure to:
- grid distribution pressure, or
- to liquefy it for gas cylinder delivery.
Biomethane is a great vehicle fuel for the replacement of LPG and CNG, but for equivalent calorific value must be compressed to higher pressures.
Home Biogas Compression – Low Tech Style!
There are also small and home biogas compression methods that are at the lowest level of the technology. The idea of these is that they deliver raw biogas to a stove gas ring. These so-called “compressors” simply comprise weights placed on the top of flexible biogas storage tanks.
The weight on the biogas storage container, in such designs, is simply provided to be sufficient to push the biogas through pipes to the kitchen where it will be used.
Most people looking for a biogas compressor will be looking for high-tech versions to provide much higher compression. Fixed speed and variable speed compressors are also available.
Biogas Compressors can be piston based reciprocating compressors, screw type, vane type, diaphragm or liquid ring type compressors.
There are a number of suppliers, such as Aerzen, Tecno Project Industriale, Avelair, Fornovo Gas S.p.A, and Bio-komp. Others also found are; HAUG Sauer Kompressoren AG, WITTIG, Bauer Compressors Inc., Mehrer Compression GmbH, and Mattei Compressors.
Essential Biogas Compressor Requirements with Examples of Suppliers
Complete Solutions for On-Site Biogas Recovery and Upgrading
Collection of the gas from anaerobic fermentation which would otherwise produce methane emissions from landfills, dairies/cattle feedlots, and wastewater facilities not only removes methane emissions into the atmosphere but may also be a source of additional revenue and profit for the operator.
Biogas extracted from biodegradable materials may be compressed and utilised as a valuable renewable fuel source.
To do this and sell the biogas in a purified form for maximum return on investment for uses such as road vehicle fuel makes sense.
A number of firms are offering a solution to the demanding gas compression equipment needed to sell the resulting biomethane fuel product. There are a number of turnkey systems available for biogas recovery and upgrading on-site and these include suitably specified biogas compressor and blower packages.
Biogas Compressor and Blower Packages
The biogas plant operator will need a specialist biogas blower and compressor package to fill gas cylinders for sale or inject biomethane into the natural gas grid.
Applied Compression is an example of a business that offers a comprehensive variety of low, medium, and high-pressure compressor and blower systems in North America.
Their packages range in size from 3 hp to about 750 hp and are suited for corrosive digester gas applications. They are intended to withstand pressures ranging from vacuum to 5,000 PSIG.
According to them, their engineers have used their company's over 50 years of expertise in gas separation and compression to become specialists in the biogas and landfill gas sectors.
Their speciality is stated to be delivering custom-engineered blower, gas compressor, and dehydration systems tailored to their client's unique requirements.
Biogas / Biomethane Compressors for Europe / Global
Hundreds of compressors installed in biogas and biomethane production facilities throughout Europe and throughout the world have, we understand, established Fornovo Gas S.p.A. as a world leader in green energy excellence.
Biogas can be produced by fermenting biomass, such as moist municipal garbage. In order to do obtain raw biogas, the biomass passes through a fermentation tank (Continuously Stirred Tank Reactor or CSTR). The biogas is then sent to the upgrading system through a low-pressure compressor. After upgrading a higher pressure is required for gas grid injection or filling cylinders.
Aerzen's biogas compressors are available for biogas applications. Whether you need to produce biomethane, feed into kilometre-long supply networks, or provide intake pressure for combined heat and power plants. Compressor technology is put to the test in biogas applications, due to the corrosive nature of the gas and high pressures which may be required.
The Aerzen biogas compressor Series C is an oil-free screw compressor in 3 sizes for volume flows up to 1900 m³/h and 3,5 bar overpressure. It is suitable for boosting the intake pressure of treatment plants for biogas or as an essential part of biogas injection plants for the compression of biomethane to inject into gas grids.
Forming the basis for this is the development competence of this world market leader, as Aerzen has innovated, optimised and provided successful compressors since 1943.
[Original article uploaded 31 Jan 2016. Latest update September 2021.]