Industry Safety: New Trends of Fire Alarm for Dangerous Waste Pits

I. Background Overview

Garbage power generation is the sorting of garbage after it is collected. among them:

Higher combustion values ​​are burned at high temperatures. Heat energy generated in high-temperature incineration (the generated smoke is treated) is converted into high-temperature steam, which promotes the rotation of the turbine and causes the generator to generate electricity.

Fermentation, anaerobic treatment of non-combustible organics, and desiccation in the final drying result in a gas called methane, also called biogas. After combustion, the heat energy is converted into steam, which drives the turbine to rotate and drives the generator to generate electricity.

However, waste fires are a deadly threat to waste incineration plants, and the most common cause of fire is the spontaneous chemical combustion of refuse and the high-temperature particles released by vehicles used to collect it. A precipitating factor for the risk of a fire or destructive explosion is the increasing concentration of methane released during the decay of litter. It can be said that the entire process of incineration of garbage, from sorting and recycling to effective conversion into electrical energy, poses a great risk of fire or spontaneous combustion and poses a hazard to people and the environment.

Incineration fire case:

November 8, 2011, Japan's garbage treatment plant fire in Tokyo

On the morning of March 23, 2015, a fire broke out at a domestic waste incineration power plant in Jilin City, Jilin Province, and a large amount of black smoke emitted from the accident site.

Second, the danger of hazardous waste pits

Dangerous waste pits are prone to fire hazards and pose serious threats to personal safety and affect the stable operation of the power plant. Under extreme circumstances, explosions may occur.

Garbage storage pools are closed, with a high temperature and high pressure environment inside. Some areas have high concentrations of dangerous gases and there is a risk of accidents.

The smoke emitted by power plants is harmful to health and the environment. Once a safety accident occurs, it will lay a greater risk for the development of the entire industry.

The non-targeted operation of the lifting equipment does not guarantee the effective treatment of the overheated area, which increases the cost of the enterprise and the labor intensity of the operator.

Third, the cause of spontaneous combustion of hazardous waste pits

Dangerous waste pits: used for the temporary storage of incineration waste, mixing and feeding preparation, storage and accumulation of various types of hazardous wastes, complex characteristics and often flammable, reactive waste in the reservoir reacts and burns violently, often spontaneous combustion phenomenon The risk of major fires is high, which brings great risks to the safety production:

( 1 ) Exothermic chemical reaction: The oxidizing agent and reducing agent mixed in the waste encounter a large exothermic chemical reaction (such as potassium permanganate and glycerol reaction explosion), and some chemicals are divided into liberation heat (such as triethyl aluminum liberation in case of moisture Hot burning);

( 2 ) Oxidation spontaneous combustion: Certain substances (such as tung oil ingredients, oil-soaked cotton hemp, magnesium aluminum, etc.) in hazardous wastes are easily oxidized by air oxidation;

( 3 ) Flammable and Explosive Products: A large number of explosives are still explosive products, such as waste paper and solvents, which are prone to fire when exposed to high temperature or fire.

Fourth, what are the current solutions

Video surveillance: Install a video surveillance device to view the stockpile through visible light monitoring. However, it is not possible to monitor the temperature and prevent monitoring.

The traditional fire warning is mainly based on the use of regular and fixed-point temperature measurement for hazardous waste pits, periodic temperature measurement inspections for each pit, detailed records, and timely reports of abnormal conditions. However, it takes a lot of manpower and consumes a lot of time, and it cannot be highly effective for early warning.

Temperature detectors and smoke detectors are installed on the top and side of the bin. However, the temperature detector can only monitor the temperature of the equipment installation point, and the overall monitoring of the entire large space warehouse lacks practicality. The smoke detector needs to have an alarm in case of smoke, which is an after-effect alarm and has no monitoring effect.

Fifth, infrared thermal imaging technology - new trends in fire alarm

Through the combination of the “Code for Fire Protection in Building Design” (GB50016-2014) and the “Technical Code for Municipal Solid Waste Incineration Treatment” (CJJ90-2009), and the past experience of fire prevention in waste incineration plants, the fuel fire safety must be Implementing the principle of "mainly prevention-based, prevention-dissipation combination", infrared thermal image technology has the following help for this environmental application of hazardous waste pits:

1 , fire alarm

Since the infrared thermal imager is a device that reflects the surface temperature of an object and is imaged, in the early stages of all firefighting hazards, disasters are often caused by invisible hidden fires. With existing common methods, it is difficult to find such hidden fire signs.

Infrared thermography technology can monitor the temperature of hazardous waste pits for a long time and discover hidden or dark fires. If the warning value is exceeded, the alarm device will be triggered within 5 seconds. It can also quickly and efficiently find the heat source caused by chemical reaction in hazardous wastes. With the lifting equipment, it can effectively treat the overheated areas, so that early warning can be prevented and extinguished early.

2. Target monitoring at night and in adverse weather conditions

At night, devices that require visible light can no longer work properly. Artificial lighting is used, and there are also blind spots. The infrared thermal imager passively accepts the target's own infrared heat radiation and can work normally during day and night. Also in the bad weather conditions such as smoke, fog, dust, etc., due to the short wavelength of visible light, the ability to overcome obstacles is poor, so the observation effect is poor, but the ability of the thermal imager to penetrate smoke, fog and dust is strong, so at night As well as harsh weather conditions, infrared thermal imaging monitoring equipment can still monitor various targets normally.

3 , fire rescue

Dangerous waste pits are prone to fire hazards, and when a fire occurs, if life-saving becomes a very tricky thing, on the scene of smoke, firefighters cannot effectively and accurately find trapped people. The infrared thermal imaging technology's smoke penetration and fogging function enables personnel to search, quickly find escape exits, monitor changes in the temperature of dangerous goods in the fire, and detect hidden sources after a fire.

This article is from the Internet.