Collocation of the hottest burner and boiler

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Matching of combustion engine and boiler

whether a full-automatic oil (gas) combustion engine (burner) with good performance is installed on a boiler, and whether it still has the same good combustion performance depends largely on whether the aerodynamic characteristics of the two match. Only good matching can give play to the performance of the combustion engine, ensure the stable combustion of the furnace, achieve the expected thermal output, and obtain good thermal efficiency of the boiler

1 matching of gas dynamic characteristics

a single automatic combustion machine is like a flame ejector, which sprays the flame into the furnace (combustion chamber), realizes complete combustion in the furnace and outputs heat; The combustion integrity of products is measured by the combustion engine manufacturer in a specific standard combustion chamber. Therefore, the standard experimental conditions are generally used as the selection conditions of combustion engines and boilers. These conditions can be summarized as follows:

(1) power

(2) air flow pressure in furnace

(3) space size and geometry (diameter and length) of furnace

the so-called aerodynamic characteristic matching refers to the degree to which these three conditions are met

2 power

the power of the combustion engine refers to how much mass (kg) or volume (m3/h, standard state) of fuel it can burn per hour when it is fully burned, and also gives the corresponding thermal energy output (kwmay 5, 2017/h or kcal/h). The boiler is calibrated for steam output and fuel consumption. The two must be matched when selecting

3 gas pressure in the furnace

in an oil (gas) boiler, the hot gas flow starts from the combustion engine and is discharged to the atmosphere through the furnace, heat exchanger, flue gas collector and exhaust chimney, forming a fluid thermal process. The hot gas flow generated after combustion, * its upstream pressure head flows in the furnace channel, just like the water in the river, * the level difference nano friction and wear experimental machine (drop, head) flows downstream. Because the furnace wall, channel, elbow, baffle, isthmus and chimney of the furnace have resistance to the flow of gas (called flow resistance), which will cause pressure loss. If the expanded signal voltage can reach 10V and the pressure head cannot overcome the pressure loss along the way, the flow cannot be achieved. Therefore, a certain flue gas pressure must be maintained in the furnace, which is called back pressure for the combustion machine. For the boiler without air induction device, the furnace pressure must be higher than the atmospheric pressure after considering the pressure head loss along the way

the size of the back pressure directly affects the output of the combustion engine. The back pressure is related to the size of the furnace, the length and geometry of the flue. Boilers with large flow resistance require high pressure of the combustion engine. For a specific combustion engine, its pressure head has a maximum value, corresponding to the maximum damper and maximum air flow state. When the intake throttle changes, the air volume and pressure also change, and the output of the combustion engine also changes. When the air volume is small, the pressure head is small, and when the air volume is large, the pressure head is high. For a specific boiler, when the incoming air volume is large, the flow resistance will increase, which will increase the back pressure of the furnace, and the increase of the back pressure of the furnace will restrain the air output of the natural combustion machine. Therefore, when selecting the combustion machine, we must understand its power curve and achieve reasonable matching

4 influence of the size and geometry of the furnace

for the boiler, the space size of the furnace first depends on the selection of the heat load intensity of the furnace, according to which the volume of the furnace can be preliminarily determined

after the furnace volume is determined, its shape and size should also be determined. The design principle is to make full use of the furnace volume; Try to avoid dead corners, have a certain depth and reasonable flow direction, and ensure sufficient reaction time to make the fuel burn completely in the furnace. In other words, let the flame emitted by the combustor have enough residence time in the furnace, because although the oil mist particles are very small(

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