Main problem
The current status of pollutant removal in the industrial boiler industry is not ideal, and the causes are very complicated. First of all, the classification of industrial boilers is unclear, the base is unclear, and its distribution is large and scattered. At the same time, the average tonnage of industrial boilers is relatively small, and the volume is much smaller than that of large-scale coal-fired boilers in power stations. However, due to the large base, the total amount of pollution emissions caused is huge. In terms of desulfurization and denitrification, since 2016, industrial boilers in many areas of the country have begun to install desulfurization, denitrification, and dust removal equipment. The technical route is basically a simplified version of the environmental protection technology for coal-fired power plants.
In terms of desulfurization technology, in order to achieve ultra-low emissions, some areas use calcium carbide slag, papermaking white mud or steel slag as desulfurization agents.
In terms of dust removal, wet electric dust removal is the last measure for ultra-low emissions. There are big problems in the denitrification technology. The SNCR method is generally used for denitrification, but it cannot meet the requirements of ultra-low emissions. The existing commercial SCR denitrification technology is difficult to apply to industrial boilers, because the existing SCR denitrification catalyst is difficult to adapt to the industrial boiler flue gas temperature window: commercial SCR working temperature is 350 ℃ ~ 420 ℃, and the industrial boiler outlet flue gas temperature is generally lower than 300 ℃ . A small number of applications are that the boiler has undergone structural transformation, and the high-temperature flue gas SCR is used for denitration and then enters the heat utilization.
Under the requirements of the situation, industrial boilers, industrial furnaces, etc. generally use low-sulfur coal as fuel, SNCR+electric dust removal+wet desulfurization+wet electric dust removal, desulfurization and dust removal can achieve lower concentration emissions, but denitrification has not yet achieved ultra-low emissions. The effect of ultra-low emission transformation of industrial boilers and furnaces (ceramics, building materials, glass, etc.) needs to be observed.
Countermeasures and suggestions
Industrial boilers: In the context of the temporary lack of desulfurization and denitrification technologies suitable for the flue gas emission characteristics of industrial boilers, the control of pollutant emissions from industrial boilers should be based on controlling the total amount of pollutants. The main measures include: 1) Strictly control fuel Quality; 2) Optimized design of boiler body and high-efficiency heat transfer elements; 3) Low-NOx combustion transformation. In areas where conditions are suitable, promote cogeneration, coal to gas, and electricity to replace coal. At the same time, it is necessary to actively develop desulfurization and denitrification technologies suitable for industrial boilers, and accelerate the targeted improvement of mature ultra-low emission technologies for coal-fired power plants.
