What are the meanings of pulverized coal boiler?

Pulverized coal boiler is an important tool for extracting coal substances, which has been widely concerned by people. So what does pulverized coal boiler mean? I believe everyone wants to know the answer to this question, so let's take a look at the meaning of pulverized coal boiler. Through the study of pulverized coal boiler knowledge, let's better apply it to daily life, so let's take a look at the meaning of pulverized coal boiler.

Concept of pulverized coal concentration

Coal is a brittle substance, which is crushed into pulverized coal under the action of mechanical force. The particle size of this pulverized coal is different, and it is a mixture of particles of various sizes. In general coal grinding equipment, the maximum particle size of lignite can reach 1000 1500tzm, the maximum particle size of anthracite is 200 ~ 250 tlm, and the particle size of most pulverized coal is 20 ~ 90 Tim. Coal powder is neither spherical nor square, but a regular polyhedron. Its surface area is very large, which is more than 100 times larger than the cube of lcm3 with the same volume, which is very beneficial to the combustion structure.

The combustion of pulverized coal needs air, and so does the transportation of pulverized coal.

This is a mixture of pulverized coal and air, usually called primary air. Pulverized coal mill plays an important role in pulverized coal reprocessing equipment. The specific gravity of pulverized coal and air is quite different. The volume of lkg pulverized coal is only about 1/2000 of that of lkg air, that is, the volume of lkg air is about 2000 times larger than that of pulverized coal with the same weight, but the two weights are equal. Here we refer to the weight of pulverized coal per kilogram of air as pulverized coal concentration, which refers to the weight share of pulverized coal in primary air. At present, the primary air pulverized coal concentration of pulverized coal boiler in operation is 0.35 ~ 0.45[ kg pulverized coal/kg air]. In order to stabilize and strengthen pulverized coal combustion, engineering often tries to form local high pulverized coal concentration in pulverized coal airflow. The problem now is how to explain the ignition mechanism of high concentration pulverized coal theoretically and determine the optimal range of pulverized coal concentration.

What concept does the "ton" in the boiler parameter "1 ton" represent?

First of all, explain the meaning of "ton" in the concept of "4 ton steam boiler". When describing the calorific value of a steam boiler, people are used to using how many tons of steam per hour to express the calorific value of the boiler per unit time, which is also called boiler capacity, boiler thermal power, boiler output and so on. It represents the heat content of tons of steam.

It indicates the heat supply or heat output per unit time when the boiler is working, and its equivalent value is 60x 104 kcal, 0.7 MW. For example, the thermal power of a 6-ton steam boiler is 6x0.7 MW or 6x0x104 kcal/hour. The working expression of calorific value attribute of hot water boiler is also expressed by "ton", which has the same meaning as the concept of steam boiler. Or it is said that a 4-ton hot water boiler generates 4 tons of hot water per hour, and a 10 ton hot water boiler generates 10 ton of hot water per hour. "Tons of hot water" cannot be used to accurately describe the thermal efficiency attribute of boilers. As we all know, the heat content of hot water with the same quality and different temperatures varies greatly. For example, the heating ratio required for 1 ton water 50 and 100 degree lifting is 1:2, and other boilers are not described in tons. Boiler is a kind of heat (heat energy) transfer, exchange and transportation equipment. Through its system work, the energy of one substance is transferred to other substances or released, so as to complete the energy exchange or transmission and transportation.

Meet the needs of people's work and life. The technical system of pulverized coal industrial boiler has the following characteristics:

(1) Centralized supply of pulverized coal: centralized grinding of pulverized coal, which is uniformly supplied by the pulverizing plant, can not only effectively ensure the stability of coal quality, but also cancel the scattered coal yard and reduce ground pollution.

(2) Friendly working environment: the whole system is closed,

Automatic coal feeding, centralized ash discharge, no dust escape. The boiler is equipped with an automatic monitoring system to reduce the labor intensity of workers. (3) The boiler is simple to start and stop: it can be started and stopped like oil-fired and gas-fired boiler systems; There is no smoldering process, so there is no reactive fuel consumption.

(4) High measurement and control level: advanced SDC control technology can realize automatic control, adjust operation parameters and make the system in an ideal operation state; At the same time, the interference of labor intensity and human factors on boiler operation is reduced.

(5) High efficiency and energy saving: the pulverized coal is fully burned, the heat exchange effect of the boiler is good, the air excess coefficient is small, and the thermal efficiency of the system is high; The heat loss of incomplete combustion of solid is small; The air excess coefficient is small (only half of that of a traditional boiler), the exhaust temperature is low, and the exhaust heat loss is small. Therefore, pulverized coal boilers have higher combustion efficiency than traditional coal-fired boilers, saving at least 30% coal. In addition, the high-efficiency pulverized coal boiler system is equipped with frequency converters for high-power induced draft fan and circulating water pump, which has obvious power saving effect.

(6) Clean emission: specialized production of pulverized coal can be realized, and advanced technology can be adopted to reduce the sulfur content in pulverized coal in the process of pulverized coal production, thus reducing the sulfur dioxide content in flue gas; The burner adopts staged combustion design, which has uniform combustion temperature field, avoids local high temperature, and produces low content of sulfur dioxide and nitrogen oxides during combustion; The fly ash in the bag filter is discharged through a closed system without secondary pollution.

(7) Land saving: the coal yard and slag yard are cancelled, and the boiler room occupies a small area.

(8) High cost performance: As the high-efficiency industrial pulverized coal boiler system adopts advanced control system and combustion technology, the initial investment of the equipment is relatively high, but its operating cost is low, and the cost performance is high in the long run. Efficient industrial pulverized coal boiler system mainly includes pulverized coal receiving and storage subsystem, burner subsystem, measurement and control subsystem, boiler body subsystem, bag filter subsystem, thermal subsystem and other auxiliary equipment. The closed tank car from the pulverized coal processing plant injects the pulverized coal that meets the quality standards into the pulverized coal tower, and the gas-solid phase separation is completed in the tower. The conveying gas is purified by bag filter and discharged into the atmosphere. The pulverized coal falls into the storage tank by its own weight, and the pulverized coal in the storage tank is discharged into the intermediate bin through the pneumatic device and the discharge valve as required. After being metered, the pulverized coal in the intermediate bin is pneumatically conveyed to the pulverized coal burner by the feeder assembly and the air-powder mixing pipeline. The combustion system adopts balanced ventilation mode (positive pressure mode can also be adopted): the conveying air is primary air, and the secondary and tertiary combustion-supporting air is sent to the burner by a blower through a separate channel. Burner and boiler furnace completely burn pulverized coal. The high-temperature flue gas generated by combustion completes radiation heat exchange with the working medium in the furnace and convection heat exchange with the working medium in the flue gas channel. After heat exchange, the low-temperature flue gas of about 150℃- 170℃ enters the bag filter, and the clean flue gas filtered by the filter bag of the filter is discharged into the atmosphere by the induced draft fan, and the fly ash collected at the bottom of the filter is cleanly discharged through the closed slurry mixing system for centralized treatment and utilization. The operation of boiler system is completed by ignition programmer, control engineering configuration software and upper computer system.

The power saving effect is obvious. (6) Clean emission: specialized production of pulverized coal can be realized, and advanced technology can be adopted to reduce the sulfur content in pulverized coal in the process of pulverized coal production, thus reducing the sulfur dioxide content in flue gas; The burner adopts staged combustion design, which has uniform combustion temperature field, avoids local high temperature, and produces low content of sulfur dioxide and nitrogen oxides during combustion; The fly ash in the bag filter is discharged through a closed system without secondary pollution.

(7) Land saving: the coal yard and slag yard are cancelled, and the boiler room occupies a small area.

(8) High cost performance: As the high-efficiency industrial pulverized coal boiler system adopts advanced control system and combustion technology, the initial investment of the equipment is relatively high, but its operating cost is low, and the cost performance is high in the long run. Efficient industrial pulverized coal boiler system mainly includes pulverized coal receiving and storage subsystem, burner subsystem, measurement and control subsystem, boiler body subsystem, bag filter subsystem, thermal subsystem and other auxiliary equipment. The closed tank car from the pulverized coal processing plant injects the pulverized coal that meets the quality standards into the pulverized coal tower, and the gas-solid phase separation is completed in the tower. The conveying gas is purified by bag filter and discharged into the atmosphere. The pulverized coal falls into the storage tank by its own weight, and the pulverized coal in the storage tank is discharged into the intermediate bin through the pneumatic device and the discharge valve as required. After being metered, the pulverized coal in the intermediate bin is pneumatically conveyed to the pulverized coal burner by the feeder assembly and the air-powder mixing pipeline. The combustion system adopts balanced ventilation mode (positive pressure mode can also be adopted): the conveying air is primary air, and the secondary and tertiary combustion-supporting air is sent to the burner by a blower through a separate channel. Burner and boiler furnace completely burn pulverized coal. The high-temperature flue gas generated by combustion completes radiation heat exchange with the working medium in the furnace and convection heat exchange with the working medium in the flue gas channel. After the heat exchange is completed, the low-temperature flue gas of about 150℃- 170℃ enters the bag dust collector, and the clean flue gas filtered by the filter bag of the dust collector is discharged into the atmosphere by the induced draft fan, and the fly ash collected at the bottom of the dust collector is cleanly discharged through the closed slurry mixing system for centralized treatment and utilization. The operation of boiler system is completed by ignition programmer, control engineering configuration software and upper computer system.