First of all, don't panic. According to the normal shutdown sequence, check whether the fuel, steam and water valves of gas-fired boiler meet the shutdown requirements.
Secondly, close the surface blowdown valve of the gas-fired boiler to prevent other faults of the boiler. Then, quickly close the main steam valve to prevent the gas boiler drum from losing water.
Thirdly, close the deaerator air supply valve, the main power switch and the natural gas valve. The air inlet of the gas-fired boiler burner should not be blocked to reduce the area of the air inlet, and the room ventilation should not be blocked to avoid the formation of toxic and harmful gases.
Different steam pressures correspond to different steam temperatures.
1. The steam temperature of low-pressure boiler is mostly saturation temperature or not higher than 400℃.
2. The outlet pressure of medium-pressure boiler is 3.8 ~ 5.4 MPa, and the commonly used steam temperature is 450℃.
3. The outlet pressure of sub-high pressure boiler is 5.4 ~ 9.8 MPa, and the common steam temperature is 540℃.
Generally, it is required that the water temperature shall be reduced to 80℃ to drain the water in the boiler. This is because if the water temperature is high, the temperature in the furnace is still very high, and the metal of the furnace wall and heating surface will still accumulate some heat. After the water is released, there is no working medium in the water wall to cool, which makes the wall temperature rise and the temperature rise is uneven, which is not conducive to the safety of the water wall.
When the water level is high, the quality of steam will drop. This is because the water level will enter the steam-water separator, and the water will slide out with the steam.
The limited space refers to a space which is closed or partially closed, relatively isolated from the outside world, with narrow entrances and exits, staff can't work in it for a long time, natural ventilation is poor, and toxic, harmful, inflammable and explosive substances or oxygen content is easy to accumulate. To define a limited space, it is necessary to meet the following three conditions at the same time, which are indispensable: the volume is large enough for people to enter completely; Or restrict the entry and exit; It's not designed to stay for a long time.
In recent years, the state has stepped up efforts of prohibiting the traditional coal-fired boilers. Major enterprises keep up with the times and purchase various environmental protection boilers. Gas-fired boiler is currently the most popular environmental protection boiler. However, due to geographical limitations in some areas, natural gas is difficult to obtain, or the cost is too high, some enterprises will choose biomass steam boilers.
Biogas boiler is a kind of boiler using biogas as fuel. It is suitable for new energy boilers in slaughter plants and breeding plants. Biogas boiler is a new type of energy-saving and environment-friendly boiler, which can not only save fuel cost, but also solve the environmental pollution problem.
Fully premixed low nitrogen condensing boiler refers to a boiler using fully premixed combustion technology. Fully premixed combustion refers to a combustion mode in which natural gas is fully mixed with air according to a certain proportion before combustion and air is no longer needed to be supplied during combustion.
The difference between ordinary gas-fired boiler and fully premixed low-nitrogen condensing boiler lies in whether air and natural gas are mixed before or after entering the burner.
