1、 Working principle of combustion engine
The working principle and main technical parameters of the burner of the combustor are that the liquid (gas) fuel is burned in the radiation chamber (furnace) of the combustor to produce high-temperature flue gas, which is used as the heat carrier to flow to the convection chamber and discharged from the chimney
2、 Working principle of combustion engine
Liquid (gas) fuel is burned in the radiation chamber (furnace) of the combustor to produce high-temperature flue gas, which flows to the convection chamber as a heat carrier and is discharged from the chimney. The crude oil to be heated first enters the furnace tube of the convection chamber of the combustor, and the crude oil temperature is generally 29. The furnace tube mainly obtains heat from the flue gas (9) flowing through the convection chamber by convection, which is transmitted from the outer surface of the furnace tube to the inner surface of the furnace tube by heat transfer, and is transmitted to the crude oil flowing in the tube by convection. The crude oil enters the furnace tube of the radiation chamber from the furnace tube of the convection chamber,
The flame emitted by the burner mainly radiates part of the heat to the outer surface of the furnace tube in the form of radiation, and the other part to the furnace wall laying the furnace tube. The furnace wall radiates the heat to the outer surface of the furnace tube on the side of the back fire surface in the form of radiation again. These two parts of radiant heat work together to raise the temperature on the outer surface of the furnace tube and form a temperature difference with the inner surface of the tube wall. The heat flows to the inner wall of the tube in a conductive manner, and the crude oil flowing in the tube continuously obtains heat from the inner wall of the tube in a convective manner, realizing the process requirements for heating crude oil.
The heating capacity of the burner depends on the intensity of the flame (furnace temperature), the surface area of the furnace tube and the total heat transfer coefficient. The stronger the flame, the higher the furnace temperature, the greater the temperature difference between the furnace and the oil flow, and the greater the heat transfer; The larger the area of the furnace tube in contact with the flame and flue gas, the more heat transfer; The better the thermal conductivity of the furnace tube, the more reasonable the furnace structure and the more heat transfer. The intensity of the flame can be adjusted by controlling the nozzle. However, for a furnace with a certain structure, the furnace temperature will not rise after reaching a certain value under normal operating conditions. The total heat transfer coefficient of furnace tube surface is certain for a furnace, so the heating capacity of each furnace has a certain range. In actual use, poor flame combustion and furnace tube coking will affect the heating capacity of the burner, so pay attention to control the burner to make it burn completely, and prevent local furnace tube temperature from being too high and coking.
3、 Operating parameters of combustion engine
Furnace temperature (retaining wall temperature) furnace temperature generally refers to the temperature at which the flue gas leaves the radiation chamber, that is, the temperature at which the flue gas does not enter the convection chamber or the temperature in front of the fire retaining wall of the radiation chamber. It is an important parameter for the operation of the burner. The heat generated by fuel combustion in the furnace (radiation chamber) is transmitted to the furnace tube through radiation and convection. The amount of heat transfer is related to the furnace temperature and tube wall temperature. The heat of crude oil obtained from combustion engine is mainly radiation heat transfer. Radiation heat transfer is directly proportional to the fourth power of the absolute temperature of the flame. Therefore, in the high temperature area, the heat absorption effect of the radiation heating surface is better than that of the convection heating surface. It absorbs the same amount of heat, and the heating area required for radiation heat transfer, i.e. metal consumption, is less than that of convection heat transfer. The furnace temperature selected in the design determines the proportion of heat absorption between the radiant heating surface and convective heating surface of the combustor. When the furnace temperature is high, the heat transfer of the radiation chamber is large, so the furnace temperature can sensitively reflect the furnace outlet temperature. However, from the perspective of operation, if the furnace temperature is too high and the heat intensity of the radiant chamber furnace tube is too large, it may lead to local overheating and coking of the radiant tube. At the same time, the temperature of the flue gas entering the convection chamber is also too high, and the furnace tube of the convection chamber is also easy to be burned, resulting in too high exhaust temperature and reduced thermal efficiency of the combustor. Therefore, the furnace temperature is an index to ensure the long-term safe operation of the combustion engine. In the oil burner, the maximum furnace temperature shall not exceed &. Exhaust gas temperature exhaust gas temperature is the temperature at which the flue gas leaves the last group of convective heating surfaces of the combustor and enters the chimney. The exhaust temperature should not be too high, otherwise the heat loss is large. The exhaust gas temperature shall be controlled during operation, and the exhaust gas temperature shall be reduced under the condition of ensuring that the combustor is in negative pressure and complete combustion. The regulation of smoke exhaust temperature generally uses the method of controlling the inlet air volume, that is, adjusting the excess air coefficient. Reducing the exhaust gas temperature can reduce the heat loss of the exhaust gas of the combustor and improve the thermal efficiency, so as to save fuel consumption and reduce the operation cost of the combustor.
This paper is compiled by Foshan Shunde Zhibo combustion engine manufacturing Co., Ltd / 。
Working principle of combustion engine Baidu Liberal Arts Literature
