There are two types of industrial boiler products. One is steam, which is used for power generation or gas supply. For example, in a fertilizer plant, steam can be used for steaming, coal is used as raw materials, and synthetic fertilizers. This is a typical industrial boiler. Most gas-fired waste heat boilers are used to recover waste heat. Common industrial boilers are circulating fluidized bed boilers. Industrial boilers are important thermal power equipment. China is a country with many boilers in the world today. China's manufacturing industry was established and developed after the founding of New China.
Structural type industrial boilers can be divided into three types: fire tube type, fire tube type and water tube type.
① Fire tube boiler; it is an early boiler. There are only one or two fire tubes for heating the pot water in the shell. There are burning devices in the fire tube. Low thermal efficiency, large volume and steel consumption, basically no longer produced after the 1960s.
② Fire tube boiler: In addition to the fire tube, a number of smoke tubes are installed in the vertical or horizontal boiler shell. The high-temperature flue gas generated by the combustion of fuel in the combustion chamber passes through these smoke pipes to heat the boiler water and is then discharged into the chimney. Compared with the fire tube boiler, due to the large number of smoke tubes, the heating area is increased, the exhaust temperature is lower, the thermal efficiency is higher, the steel consumption and the boiler volume are smaller. Figure 1 is a horizontal tempering tube boiler. The evaporation capacity of a fire tube boiler is generally not more than 15 tons per hour, the working pressure is generally not more than 1.6 MPa, and the thermal efficiency of coal combustion is generally about 70%. The thermal efficiency of all automatic fuel oil boilers can reach 85%.
③ Water tube boiler: Mostly used as industrial boiler with large capacity and high pressure. There are two types of water tube boilers: natural circulation and once-through. Natural circulation water tube boilers have single and double boiler drums. Figure 2 is a double boiler water tube boiler. This boiler is generally equipped with an economizer and sometimes an air preheater after the convection tube bundle to reduce the exhaust temperature. Efficiency can reach 80% when burning coal, and higher when fuel. There is no drum in the once-through industrial boiler, and the heating surface is composed of a tube coiled on the inner wall of the furnace and a convection tube bundle at the back. Feed water enters from one end of the pipe and steam exits from the other. Once-through industrial boilers are small in size and generally have a steam-water separator and an automatic control device.
Fuels and combustion equipment Industrial boilers use a wide variety of fuels, including coal (bituminous coal, anthracite, lignite, coal gangue, etc.), oil (heavy oil, residue oil, diesel, etc.), gas (natural gas or various industrial by-product gases), plants And urban waste (timber, bagasse, papermaking black liquor and garbage, etc.). Therefore, the combustion equipment of industrial boilers is also diverse. Belonging to the layer combustion equipment are chain grate, lower feeding grate, reciprocating grate, vibration grate, coal thrower and chain grate (see grate). It is also useful for boiling combustion (see boiling furnaces). Pulverized coal is generally used in coal-fired industrial boilers with an evaporation capacity of 65 tons / hour or more.
Heating boilers belong to the category of civilian life boilers. With the improvement of people's safety awareness, generally we refer to heating boilers as normal pressure hot water boilers.
There are many types of heating boilers, and their classification is mainly divided according to the type of fuel. Heating boilers can be divided into electric heating boilers, oil heating boilers, gas heating boilers, coal-fired heating boilers, and biomass heating boilers according to different fuels. The fuel oil includes: diesel, kerosene, heavy oil, etc .; the fuel gas includes: natural gas, liquefied gas, city gas, biogas, etc.
