On February 9, the Emergency Management Department of Yunnan Province reported the "1.29 rural biogas poisoning incident in Yuanmou County, Chuxiong Prefecture".
In rural areas, biogas digesters, cellars, waste wells and other places
Limited space accidents are very hidden,
Many people do not have relevant safety knowledge and security awareness,
After the accident, due to the lack of awareness of the hazard,
Rushing to save people and ignoring protective measures,
This led to an increase in casualties.
Methane, the main component of biogas, is an ideal gaseous fuel. It is colorless and odorless, will burn when mixed with the right amount of air, and is a good clean fuel.
In addition to direct combustion, biogas can also be used for cooking, drying agricultural and sideline products, heating, lighting and gas welding, etc., as well as as fuel for internal combustion engines and chemical raw materials for the production of methanol, formalin, carbon tetrachloride and so on. In addition, the liquid and sediment discharged after fermentation by the biogas unit contain rich nutrients and can be used as fertilizer and feed.
However, biogas is also quite dangerous, the main component of biogas is methane, if the air contains 8.6-20.8% (in terms of volume) of biogas, it will form an explosive gas mixture. Secondly, the biogas also contains carbon dioxide, hydrogen sulfide, phosphine, nitrogen and other toxic and harmful gases, when the human body inhales biogas, it is easy to cause poisoning, and even cause death soon.
Biogas poisoning accident cases
- Case 1
At about 22:00 on March 28, 2018, a biogas poisoning accident occurred in Shaoying Village, Xingliu Town, Yingquan District, Fuyang City, Anhui Province. A farmer was poisoned by biogas while cleaning up a sewage pond, and those who came to the rescue later were also stunned by biogas, resulting in the death of 4 people.
- Case 2
On the morning of March 31, 2018, four villagers in Yunfeng Village, Cangxi County, Guangyuan City, Sichuan Province, had an accident while cleaning up the digester, and no one survived.
- Case 3
On the night of February 24, 2019, in Yantai Town, Matjiang County, Chongqing City, local villager Wang Mousheng was trapped in the biogas pond of his pig farm, and his wife Huang Moulan, the eldest son Wang Mouqiang, the second son Wang Moulei, and the neighbor Wang Moubo successively went down to the pool to rescue the trapped. The accident resulted in the death of 4 people.
- Case 4
At about 16:00 on July 22, 2019, employees of Great Wall Biochemical Engineering Co., Ltd. in Huailai County, Hebei Province, were poisoned by biogas while cleaning up the sewage sedimentation tank in the plant area, and 5 people were killed.
- Case 5
On the morning of November 15, 2020, a rural household biogas accident occurred in Mata Town, Jingyan County, Leshan City, Sichuan Province, resulting in four deaths. After investigation, the deceased Zhou Mouguang was poisoned by biogas in his own cellar pond pickled pig grass, and after the deceased's relatives Zhou Mou'an, Zhou Mouhong, and Zhang Mouqiao were discovered successively, they went down to the cellar pool for rescue, and all the biogas was poisoned, and the rescue was ineffective and died.
How to avoid accidents?
In the countryside, biogas digesters, cellars, waste wells and other places limited space accidents are very hidden dangers, many farmers do not have relevant safety knowledge and safety awareness, of which biogas digesters are closely related to rural production and life, so the frequency of use is higher, accidents occur more, so how to safely use biogas digesters, in order to avoid accidents?
Biogas digester operation, how to avoid danger?
1. Before entering the digester and dry well, open the movable cover plate and ventilate it with an exhaust fan. Then tie chickens, ducks, rabbits and other small animals into the basket, and tie them into the pool with a rope for 20 minutes. If there is no adverse reaction, the personnel can enter the pool to work, and if the small animal reacts abnormally, the ventilation and ventilation should continue until there is no longer a danger.
2. Personnel entering the digester should tie a safety rope in the chest and have a special person outside the pool to guard it. If an accident occurs to the person under the pool, the safety rope can be immediately pulled outside the pool to rescue the person, and it is strictly forbidden to operate alone.
3. When entering the digester for maintenance, especially when the sediment is discharged, do not use open flames such as candles to illuminate, so as to avoid burns and explosion accidents.
4. If you find that someone in the pool has fainted, you must not recklessly go down the pool to rescue. It is best to try to ventilate the air into the pool as quickly as possible, and let the people in the pool absorb fresh air first. If the ventilation cannot be done quickly, the rescue personnel must do a good job of safety protection to rescue, and blind rescue is strictly prohibited.
With the advancement of technology, many industries that use biogas will use online biogas analysis systems to monitor biogas in real time, and methane sensors are generally used in the system:
The solution given by the technical engineer of the mining network is to use the FSM-T-01 pre-calibration module FSM-T-01 of FIGARO FIGARO methane gas in Japan
The FSM-T-01 is a pre-calibrated module for methane gas alarms. The methane gas concentration is measured using a TGS2611 sensor and optimized classic circuitry, pre-calibrated by Figaro's high-precision calibration equipment, and produced using a proven aging process. This module is designed to minimize the development and production costs for users, so that users can easier and simpler to manufacture civil gas alarms. Figaro Figaro methane gas pre-calibration module FSM-T-01 features: gas concentration digital quantitative output by communication, programmable alarm point output, factory calibration, temperature compensation, small size, low cost.
At the same time, it can also use the British Clairair infrared gas sensor - S509-CH4, S509-CH4 is based on the Bill-Lambert law and infrared spectroscopy theory, can accurately detect methane, carbon dioxide, hydrocarbons and so on. And the British alphasense (CH4 sensor) - CH-A3, CH-A3 is the use of catalytic combustion of the thermal effect principle, by the detection element and compensation element paired to form a measurement bridge, when encountering flammable gas, combustible gas in the detection element carrier surface and catalyst under the action of combustion, the carrier temperature will increase, through its internal platinum wire resistance is also correspondingly increased, so that the balance bridge out of balance, output an electrical signal proportional to the concentration of combustible gases.
In daily life, sewer pipes, inspection wells, cellar wells, septic tanks, biogas digesters and other facilities due to microbial action, low terrain and relatively closed, easy to produce biogas, we must improve their own safety awareness, biogas safety issues can not be ignored!