Who can tell me coal-fired boilers and the advantages and disadvantages? Including safety, environmental protection, economic three aspects

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# Coal gasification phase combustion boiler structure and application

Boiler in the process of development has always attached importance to the improvement of the boiler's thermal efficiency and soot emissions to meet the standards of the two major problems. The traditional boiler to solve these two problems is basically to rely on enhanced combustion and heat transfer to improve the thermal efficiency of the boiler and set the furnace dust collector. Enhanced combustion often leads to increase the initial emission concentration of boiler dust, increasing the burden of dust collector, in developed countries can use dust removal efficiency of more than 99% of the electric precipitator or bag filter, so that the concentration of dust emissions control in the following 50mg/Nm3, while in China due to the economic conditions of the reason, can only use the relatively inexpensive mechanical or wet-type dust collector, the efficiency of the dust removal is generally less than 95%, so that the concentration of dust emissions greater than 100-Nm3, and the dust emission concentration of more than 100-Nm3, the dust emission concentration of more than 100-Nm3. The dust removal efficiency is generally less than 95%, so that the concentration of soot emission is more than 100-200 mg/Nm3, which is not up to the national environmental protection requirements. This relies on the outside of the furnace dust collector to solve the dust removal method, not only to increase the footprint of the boiler room and infrastructure investment, but also increase the induced draft fan power consumption, but also cause secondary pollution. As the coal gasification split-phase combustion boiler completely changed the traditional boiler combustion principle, the use of gas-solid split-phase combustion theory, so that the coal in the combustion process is prone to produce black smoke in the combustible volatile hydrocarbons in the combustible gas first, with the removal of volatile coal coke combustion in the combustion chamber together. As the temperature of the combustion chamber is up to 1000℃ or more, the smoke can be fully decomposed, which solves the problem of black smoke produced by the direct combustion of coal. This kind of boiler not only makes the raw coal burn as completely and efficiently as possible, with high thermal efficiency, but also reduces the emission of soot and harmful gases such as SO2 and NOX as much as possible, and achieves the effect of eliminating soot and dust, so that the boiler's various environmental protection and energy-saving indexes are much better than the national standards.

The application of coal gasification split-phase combustion technology in the boiler breaks the traditional boiler and dust collector mode, and creates an integrated mode without the need for a dust collector outside the furnace. And this integration is not mechanically adding the dust collector to the boiler. The coal gasification split-phase combustion boiler has its own unique structure compared with the ordinary gas boiler and the layer-fired boiler, which organically combines the latter two, and mainly consists of three major parts: the coal gasification chamber in the front, the combustion chamber in the middle, and the convection heating surface in the tail.

# Coal gasification split-phase combustion boiler characteristics

The traditional way of coal combustion produces a large number of pollutants in the process of coal combustion, causing serious environmental pollution. The main reasons are:

(1) coal is not easy to fully contact with oxygen and the formation of incomplete combustion, low combustion efficiency, a relative increase in pollution emissions;

(2) the combustion process is not easy to control, for example, volatile components of a large number of precipitation is often insufficient supply of oxygen, resulting in the precipitation of soot and black smoke;

(3) the temperature of the solid combustion of fuels is difficult to be uniform, the formation of a high-temperature area of localization

(4) Most of the sulfur in the raw coal is oxidized to SO2 in the combustion process;

(5) When untreated solid coal is burned directly, a large amount of dust will be discharged along with the flue gas, resulting in a large amount of dust pollution.

The coal gasification split-phase combustion boiler integrates coal gasification and gas-solid split-phase combustion into a single unit, which effectively solves the problem of environmental pollution, and has the following advantages compared with the traditional coal-fired boilers:

1. Low concentration of smoke and dust, low blackness of the flue gas, and good environmental performance.

2, energy saving, high thermal efficiency.

3, low emission of nitrogen oxides

4, some desulfurization

5, simple and easy to operate and control

6, stable combustion, coal adaptability