Stainless steel for pressure vessels and its welding characteristics. The so-called stainless steel refers to the addition of a certain amount of chromium in the steel to keep the steel in a passive state and free from rust. Jiangsu Miniature steam generator For this purpose, the chromium content must be more than 12%. In order to improve the passivity of steel, it is often necessary to add nickel, molybdenum and other elements that can passivate steel into stainless steel. Stainless steel is generally referred to as stainless steel and acid resistant steel. Stainless steel companies do not have certain acid resistance, and acid resistant steel generally has a good stainless property. vertical Miniature steam generator manufactor According to its steel structure, stainless steel can be divided into four categories, namely, austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, and austenitic ferritic duplex stainless steel.
As is known to all, the boiler using sensible heat of various waste gases and waste heat after waste incineration as heat source is called waste heat boiler, also called waste heat boiler. Therefore, the country advocates vigorously developing waste heat utilization, energy conservation and emission reduction, which plays a positive role in protecting energy and improving the quality of human living environment. Jiangsu Miniature steam generator In the design of waste heat boiler, how to reasonably divide the temperature range is the basis for reasonably arranging the heating surface of waste heat boiler and making maximum use of waste heat. Under the condition of a given exhaust gas temperature at the inlet of the waste heat boiler, there are two requirements for the exhaust gas temperature. One is to limit the exhaust gas temperature, which is required to be within a reasonable range; The other is that the exhaust gas temperature is not limited, requiring greater use of waste heat. vertical Miniature steam generator manufactor In either case, for medium and low temperature waste heat utilization, the narrow point temperature difference directly affects the evaporation capacity of the waste heat boiler and the layout of the heating surface. Narrow point temperature difference, also known as node temperature difference, is a small temperature difference between evaporator outlet flue gas and heated saturated water vapor during heat exchange. With the change of narrow point temperature difference, the relative total heat exchange area, relative evaporation capacity and relative exhaust gas temperature of the waste heat boiler also change.
The starting of gas-fired boiler shall be carried out according to the operating procedures. The following is the accurate starting process of the analyzed gas-fired boiler: turn on the main power supply, start the gas-fired incinerator, and close the vent valve on the drum when it emits steam. Jiangsu Miniature steam generator Check the manhole, handhole flange and valve of the gas boiler. If any leakage is found, fasten them. If leakage occurs after fastening, shut down the boiler for maintenance. When the gas pressure of the gas boiler rises by 0.05~0.1MPA, make up water, blow down, check the experimental water supply system and blow down equipment, and flush the water level gauge together. When the gas boiler pressure rises to 0.1~0.15MPA, flush the pressure gauge trap; When the gas pressure of the gas-fired boiler rises to 0.3MPA, turn the "load high fire/low fire" knob to "high fire" to strengthen incineration. When the pressure of the boiler rises to 2/3 of the operating pressure, start pipe warming and air supply, slowly open the main steam valve to prevent water hammer. vertical Miniature steam generator manufactor When the drain valve emits steam, close it. After all the drain valves are closed, slowly open the main gas valve to fully open, and then reverse it for half a circle. Turn the "Control of gas incinerator" knob to the automatic gear.
Effectively prevent and reduce low temperature corrosion of air preheater. Low temperature corrosion is caused by sulfur dioxide generated by combustion of sulfur in fuel. Jiangsu Miniature steam generator Under the action of catalyst, sulfur dioxide is further oxidized to sulfur trioxide. Sulfur trioxide and water vapor in the flue gas generate sulfuric acid vapor, which greatly increases the dew point of the flue gas, condenses the sulfuric acid vapor on the flue gas side of the preheater tube wall, causing sulfuric acid corrosion of the preheater. The content of sulfur trioxide has a great impact on the corrosion rate of the preheater. The content of sulfur trioxide is not only related to the sulfur content in the fuel, but also related to the oxygen content in the flue gas. vertical Miniature steam generator manufactor Low oxygen combustion can significantly reduce the oxygen content in flue gas, greatly reduce the amount of sulfur dioxide oxidized to sulfur trioxide, reduce the dew point of flue gas, and effectively reduce the corrosion of preheater. Low oxygen combustion reduces the amount of flue gas. It can not only reduce the exhaust gas temperature, improve the boiler efficiency, but also reduce the power consumption of the forced draft fan and the wear of the heating surface.