Refractories for boilers

Boiler as a thermal power equipment has a history of more than 200 years, it is an important equipment to convert the chemical energy stored in coal, oil or natural gas into water or steam heat energy. The heat energy of high temperature water and steam can be directly applied in life and production, such as air conditioning, textile, chemical, papermaking and other fields; it can also be converted into other forms of energy, such as electric energy, mechanical energy. With the expansion of thermal energy application of water and steam, boiler has gradually become an indispensable power machinery in all fields of production and life of human society. With the rapid development of material production and the increasing consumption of energy, human society needs more and more advanced energy conversion equipment, and the role and position of boiler industry in the national economy is becoming more and more important.

Modern boilers can be seen as a huge steam generator. After coal, oil or natural gas are fed into the boiler, the combustion equipment burns it, and the chemical energy of the fuel is converted into the heat energy of the combustion product, the flue gas. High temperature flue gas transfers heat energy to feed water through various heat transfer modes, and water supplies heat energy in the form of steam or man to industrial and agricultural production and human life, or to generate electricity and act as the driving force for mechanical movement. The boiler for power generation is generally called power station boiler, while the boiler directly supplied to industrial and agricultural production or driving machinery is called industrial boiler or ordinary boiler.

With the development of boiler industry, the capacity of industrial boiler or ordinary boiler has developed from producing hundreds of kilograms of steam per hour to producing dozens of tons of steam per hour, and the performance of boiler has also changed essentially. The efficiency of industrial boilers has been improved from 20%~30% to 70%~80%. The original heavy manual operation has now been mechanized and automated.

Foreign industrial boilers mainly use oil and natural gas. Since the world energy crisis in the early 1970s, coal resources have been paid more attention to because of the high price of oil and gas fuel. However, in order to prevent environmental pollution, coal-fired boilers have developed greatly in purifying combustion products. The characteristics of foreign industrial boilers are large average single machine capacity, high thermal efficiency, perfect automation control degree, development of boiler units in the direction of fast loading or assembly, compact structure and convenient site installation.

The industrial boilers in our country mainly use all kinds of raw coal, and the supply of coal varies greatly, so the actual operation thermal efficiency of the boiler is low. The single machine capacity is low, the automation control degree is low. In recent years, while absorbing the advanced technology of foreign countries, the boiler scientists in our country have made great progress in boiler design and have reached or approached the world level. The boiler manufacturing industry is also constantly updated, and the boiler manufacturing standards adopted in China have basically met the international standards.

The ordinary boiler is composed of boiler pipe system, combustion chamber, flue and dust collector, and its working pressure is not high, which is mainly used in industrial and civil heating departments. This kind of boiler form is many, the quantity is big, most uses the coal as the fuel, also has burns the heavy oil or the gas.

The working process of boiler is composed of combustion process and heat transfer process. Many and complex boiler components are designed to complete and strengthen these two processes. According to the working process of the boiler, the boiler can be divided into two parts: boiler body and combustion equipment.