Economic efficiency and legal security of biogas plants
In the set of rules, TRAS 120 (The Technical Rule for Plant Safety "Safety Requirements for Biogas Plants") drawn up by the BMU (Federal Ministry for the Environment, Nature Conservation and Nuclear Safety), the immision protection issues of biogas plants and the inspection are regulated.
The large-scale monitoring of biogas plants carried out by the Baden-Württemberg trade inspectorate in 2013 and 2014 revealed considerable safety and environmental deficits. Defects were found in almost every second system. Due to the high risk and hazard potential, system operators will have to reckon with closer monitoring in the future. The complex, technical and legal requirements cause farmers to fall back on expert support if they want to guarantee the legally secure operation of their plant. In addition, economic losses from escaping gas can be avoided.
As with natural gas, methane (CH4) is the main chemical component of biogas. This hydrocarbon is extremely flammable and is classified as potentially explosive.
The technical rule for hazardous substances (TRGS) 529 has been in force since April 2015, which regulates the "activities involved in the production of biogas". Among other things, it states that a “responsible” person and a representative must be appointed to operate a biogas plant. This can be the operator or a person from the group of employees with the same specialist knowledge.
The aim of this regulation is to protect employees, often family members on agricultural properties. Statutory accident insurance assumes liability for work accidents involving employees and family members. To this end, the employers liability insurance associations issue regulations that have the character of a law. For the farmer, the operational safety, workplaces, organic and hazardous substances regulations also apply.
Inspection and maintenance of the biogas plant
Both in the construction and in the operation of biogas plants, a wide range of legal regulations must be observed that relate to immission control, recycling law, explosion and water protection, building law, the Hazardous Substances Ordinance and product safety law.
According to this, the same standards apply to biogas plants as have long been practiced in the area of municipal gas supply networks and industrial plants. In the event of damage, deviating from the recognized and proven technical rules can have considerable disadvantages and result in claims for damages.
Advice and support from knowledgeable specialists help the system operator to meet his organizational obligations. The qualification criteria of the DVGW (German Association for Gas and Water) are a decisive help when choosing a suitable specialist company. The DVGW issues test certificates for both specialist companies and gas detectors, thus ensuring legal security, especially in the event of damage.
When selecting external testing companies, operators should ensure that the service providers can provide evidence of the following certifications:
- DVGW G 468-1 – test certificate for specialist companies
- DVGW G 468-2 – test for gas detectors
- DIN ISO EN 9001 – quality management system (according to DAkkS standard
Tightness test of biogas plants
Larger containers, such as fermenters or secondary fermenters, cannot be unequivocally checked with conventional measuring devices, which is why imaging methods must also be used when searching for leaks. Infrared cameras, for example, which are able to determine methane (CH4) and volatile organic compounds and which can also be used in potentially explosive areas according to the ATEX II standard, are suitable for this purpose. Infrared laser devices, on the other hand, only measure methane at distances of 30 to 100 m (the laser beam must be returned via a reflective surface) and a measuring range of 1 - 50,000 ppm x m.
Lines laid underground are checked above ground with the carpet probe. The aim of the measurement is to localize gas concentrations in accordance with DVGW guidelines. Once you have determined gas concentrations, you usually do not yet know exactly where the leak is. Depending on the nature of the subsoil and the sealing of the surface - for example with bitumen - the gas spreads unpredictably in the ground and even forms so-called nests. Therefore, the leak is systematically localized with the help of test boreholes and gas analyzes. The leaks are categorized according to the possible hazard potential and a maintenance, action and repair plan is drawn up.
In the case of exposed lines, the leakage check is carried out with conventional gas measuring devices. When evaluating the measurement result, however, the type of detection device used must be taken into account. Special probes are used depending on the nature of the terrain.
The classification of the leak and determination of the further measures are carried out according to the industry standards. A loss determination and classification is carried out in accordance with the DVGW guidelines.
Installation and inspection of biogas warning systems
When operating biogas plants, in addition to process optimization, personal protection and plant safety are of decisive importance. Early detection in the Ex area can prevent damage or contain existing ones. Since the main hazard in a biogas plant is the risk of explosion, the engine rooms must be monitored with gas warning systems in accordance with the safety rules for biogas plants. The systems used for monitoring must not pose a risk of ignition.
Biogas plants require safety precautions to protect the technicians while they are working. The gas mixture produced by the decomposition of organic material can be toxic and harm technicians. The use of gas warning systems and the correct placement of the sensors on a biogas system reduce explosive and toxic gas hazards.
It is necessary to have the systems used regularly checked for functionality and reliability. Among other things, the response sensitivity and response time, but also the safe switching of the relays are checked. This means that compliance with the requirements (94 / EC, EN50054, EN50057 and safety rules for biogas plants) must be guaranteed by the operator.
In order to guarantee security around the clock, Schütz Messtechnik offers a gas alarm system that can be installed in the entire biogas plant.
- Your planner selects the right system
- Schütz sets up the system in advance
- Your electrician will install according to our specifications
- The system is put into operation by us. You will receive a log
- We offer the service and the mandatory annual inspection
The devices must be subjected to regular inspections by trained specialists. The maintenance interval depends on the connected sensors and can be found on the maintenance sticker. Test gas is to be applied to the sensors. The concentration to be used should trigger the main alarm on the devices. If necessary, the sensors or the evaluation device must be recalibrated. Appropriate controls must ensure that the area around the devices is always clean, accessible and visible.