Cisterns for biogas

- central to the energy transition

Biogas tanks can be renovated

Biogas is an important energy source in the transition to renewable energy. It is used for heat, electricity and vehicle fuel. It is produced on a small scale on farms and on a large scale for heating plants and industries. Cisterns are present throughout the process - to store substrates and to produce and store the biogas. Biogas cisterns can be damaged by corrosive substances in the gas. Biogas is flammable and explosive, so safety requirements are high. Be on the safe side! Inspect regularly so that you can address small damages in time. Cistern Solutions has developed an effective method to repair damaged tanks.

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Cisterns for two forms of biogas: compressed and liquid

Biogas is produced by decomposing organic matter in an oxygen-free environment. The substrate, as it is called, can be sewage sludge, food waste, manure and industrial waste. Decomposition takes place in digesters, where bacteria convert the organic matter into methane and carbon dioxide, i.e. biogas. The gas is compressed and stored under pressure or cooled down to liquid gas. Both forms of biogas are stored in tanks. So is the biosludge, a by-product used as fertilizer in agriculture.

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Problems with biogas tanks

The most common problems for biogas tanks are cracks and leaks. Biogas often contains corrosive substances such as hydrogen sulphide and ammonia. In a humid environment, hydrogen sulphide can form sulphuric acid, which corrodes the tank contents. Another problem is the accumulation of sludge which can block the valves. Blocked valves can lead to overpressure which in turn increases the risk of explosion. If the gas cannot be vented out, it will try to find other ways out. Leaking biogas is a major fire hazard. If the gas is toxic, it can harm people who are nearby.

Safety around biogas tanks

Biogas tanks, especially those used for compressed or liquefied biogas, are considered as pressurized equipment. This also applies to loose containers of biogas. A biogas tank is also classified as handling flammable liquids or waste oil (see MSB's regulations). According to the Swedish Work Environment Authority's regulations, tanks and pipelines must be inspected regularly to reduce the risk of accidents and protect human health. The inspection must be carried out by an accredited inspection body.

  • A cistern should be checked when it is installed.
  • If the tank undergoes repairs, an overhaul inspection must be carried out before the system is used again.
  • When a cistern is decommissioned, it must be notified to the authorities. If it needs to be removed, there are instructions on how to do so safely.

To protect soil and water, tanks with connected pipelines must have secondary protection. The protection can catch leaks, prevent explosion and fire or detect gas leaks (for more information on requirements for secondary protection, see the Swedish EPA's regulations NFS 2021).

Saving a damaged biogas cistern

Cisterns need to be protected with a coating designed to protect the tank from corrosive substances in the gas. But to do its job, the coating must be intact. Regular inspection will help you detect problems in time. Because there is something you can do about them. Cistern Solutions has extensive experience working with epoxy and polyurethane coatings. In recent years, we have developed an effective method for repairing damaged tanks. The result meets the high inspection requirements with a good margin. Extend the life of your biogas tank and ensure sustainable and efficient biogas production by inspecting frequently and fixing small defects before they become big problems.

Securing all types of biogas tanks

Contact us and we will tell you more about how we work with renovating biogas tanks!

I want to know more about biogas cistern renovation

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