Analysis of common accidents of gas oil drying fur

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Analysis of common accidents of gas and fuel oil drying furnaces for steel barrel coating

in recent years, with the gradual improvement of awareness of environmental protection and the widespread use of natural gas and other energy sources, more and more oil or gas drying methods have been used in steel barrel coating drying furnaces. During the drying process of the steel barrel, the alkene volatile of the paint on the surface of the steel barrel can be recycled by the burner and then burned for reuse, which not only reduces the production cost, but also reduces the environmental pollution. Therefore, most enterprises that originally used electric heating, far-infrared and steam (coal-fired) stoves considered using oil or gas for drying during technological transformation. However, with the use of oil and gas stoves, some new unsafe factors have emerged. Because enterprises still lack technology and experience in the use of new energy such as oil or gas, safety accidents occur from time to time, causing many people to make mistakes in understanding that oil and gas are unsafe

in fact, some abnormal phenomena and accidents that often occur during the operation of the drying furnace are generally caused by the operator's lack of familiarity with the technology. Therefore, it is required that the operators should master the equipment conditions and skilled operation skills, and carefully maintain and correctly operate the equipment, which is the primary guarantee for the safe operation of the drying furnace

when an accident occurs during the operation of the oven, the general principle of dealing with the accident is to eliminate the root cause of the accident as soon as possible, and on the premise of ensuring personal safety and equipment damage, try to restore the normal operation of the oven or do not expand the accident. Therefore, when dealing with accidents, operators should be calm, make correct judgments, and be able to deal with accidents accurately and quickly

there are many types of accidents of drying furnaces. The following is an analysis of several common accidents of oil and gas drying furnaces. In order to attract widespread attention and reduce accident losses

(I) tempering and fire off of gas oven

1. Tempering and fire off phenomenon. The negative pressure in the furnace is unstable, sometimes large and sometimes small; The indicated values of CO2 and O2 in flue gas have significant changes; The flame length and color change

2. Causes of tempering and de ignition. The combustion of gaseous fuel has a certain speed. When the concentration of gaseous fuel in the air is within the range of combustion limit concentration, and the flow rate of combustible gas at the burner outlet is lower than the combustion speed, the flame will spread to the direction of fuel source and backfire will occur. The higher the furnace temperature, the faster the flame propagation speed, and the easier it is to produce tempering. Tempering will burn the burner, and in serious cases, gas explosion will occur in the gas pipeline

on the contrary, if the flow rate of combustible gas at the burner outlet is higher than the combustion speed, the ignition point will be far away from the burner and de ignition will occur. During low load operation, the furnace temperature is low, which is more likely to cause ignition failure. Flameout can make the combustion unstable, and in serious cases, it may lead to the flameout of a single burner or furnace

the speed of gaseous fuel is converted by pressure. If the pressure of the gas pipeline changes suddenly, or the characteristics of the pressure regulating valve in the pressure regulating station and the gas printing test report regulating valve in the oven are poor, so that the gas pressure into the furnace rises or falls, and the air volume is adjusted improperly, etc., it may cause the instability of the gas flow at the outlet of the burner and cause backfire or flameout

3. Treatment and prevention of tempering and de ignition. To prevent flashback and fire loss, the pressure of fuel gas should be kept within the specified value. In order to prevent possible accidents caused by tempering, flame arresters (flashers) should be installed on the gas pipeline. When the pressure is too low to be found in time, the flame arrester can automatically extinguish the flame

when tempering or misfire occurs, the cause should be quickly identified and handled in time. First, check whether the gas pressure is normal. If the pressure is too low, the entire gas pipeline shall be inspected without steel buckle adhesion. If the pressure of the main gas supply pipeline of the drying furnace decreases, check the inlet pressure of the pressure regulating station first. When the pressure decreases, contact the gas supply station to increase the gas supply pressure; If the inlet pressure is normal, check whether the pressure regulating valve has faults and eliminate them in time. At the same time, switch to the standby pressure regulating valve and open the bypass valve; If the above measures are still ineffective, check whether there is leakage in the whole gas pipeline and whether the valve that should be closed (such as the vent valve) is not closed, and try to eliminate and correct it. If only the pressure of the gas pipeline in front of the boiler decreases, check whether the valves on this section of the pipeline are normal, whether the opening is appropriate, and whether there is leakage. When the gas pressure cannot be restored to the normal value, the number of burners in operation should be reduced and the load should be reduced until the drying operation is stopped

if the gas pressure is too high, it is necessary to check whether the regulating valves on the R & D pipeline of the whole gas that has invested a lot of money in antibacterial materials are normal, then check whether the opening of the air valve of each burner is appropriate, check whether the total air pressure on the air duct and the air pressure in front of each burner are too high, and make corresponding adjustments

(II) furnace fire extinguishing

when fire extinguishing occurs in the furnace, it will generally affect the continuous output of the oven; More importantly, if it is not found and handled in time, it is easy to cause 3 The beam can be moved, which can realize the non grade adjustment of the experimental space In addition to meeting the test of rubber bearings, corresponding auxiliary tools can also be added, and some large sample tightening experiments can be done Explosion

1. Phenomenon of oven fire extinguishing. In case of fire extinguishing in the furnace, the furnace is dark, and the flame cannot be seen from the fire hole; Action of fire alarm device; The negative pressure in the furnace suddenly increases

if it is found that the fire extinguishing of the oven is late, the fuel sent into the oven will be stored until a certain time, and all of it will ignite in an instant, which will lead to an explosion

2. Causes of furnace fire extinguishing. The unstable combustion of the oven is a precursor to extinguishing the fire. According to the conditions required for stable ignition and other aspects, the main reasons for fire extinguishing are:

① the oven load is too low, and the temperature of the combustion chamber is low at this time, which is not conducive to the heating, ignition and stable combustion of new fuel

② fuel properties change or fuel is interrupted for a short time

③ the negative pressure in the combustion chamber is too large, causing the flame to be pulled off

④ improper air volume adjustment. For example, the primary wind speed is too large, and the air volume is too large at low load

⑤ induced draft fan or forced draft fan trip and power failure, fuel system failure or power failure, etc

⑥ induced draft fan or forced draft fan trips and power is cut off, fuel system fails or power is cut off, etc

for the oil fired oven, when the external interference exceeds the stability of the burner, even if it is instantaneous, the air-fuel ratio will exceed the combustible range of combustion. At this time, the oven fire extinguishing phenomenon may occur. The main reasons for extinguishing the fire in the oil fired oven are as follows:

① water in the oil

② oil supply interruption

③ the air system including forced draft fan is abnormal, and the air volume changes greatly

④ combustion interruption will occur when the burner or important part of the combustion device is inappropriate

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