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Reforming Technology of Boiler Denitrification

At present, national energy policy and environmental policy are becoming more and more stringent on coal and electricity projects. Combined with the current national policy on the prevention and control of air pollution more and more strict, NOx emission standards from 200 mg / Nm3 reduced to 100mg / Nm3, some key sensitive areas is required to reach 50mg / Nm3 below. At this stage of coal, gas, waste heat boiler denitrification technology has three main directions. First, SNCR denitrification technology; Second, SCR denitrification technology; Third, low nitrogen combustion denitrification technology. Through a single technology or a combination of three technologies to achieve the state and the owners of nitrogen oxide emissions requirements. After the first batch of denitrification transformation of China's large-scale boiler has been basically completed environmental upgrades, some medium-sized power plant boilers are basically completed the denitrification transformation. At present, there are some small and medium-sized cogeneration, enterprise-owned power plants, air pollution control policies loose areas of remote power plants and heating boilers and other parts of the boiler has not been upgraded to upgrade; the first batch of denitrification projects due to up to Less than the design value or due to environmental requirements to improve the need for secondary transformation of the boiler.

Boiler design, transformation has been our company's main business, in recent years our company is committed to working with environmental protection companies to jointly boilers desulfurization, denitrification environmental protection upgrade. Based on current market situation, through the implementation of a number of projects, our company summed up the different furnace of boiler denitrification heating surface transformation technology.

Main technical features:

1, fluidized bed boiler, pulverized coal furnace, chain furnace denitrification heating surface transformation technology

Fluidized bed boiler, pulverized coal furnace, chain furnace denitrification heating surface transformation of the two technology,

一、low-nitrogen combustion technology, through the boiler furnace burner, secondary air, central drum and other boiler core components transformation, so that the boiler can achieve the state of graded combustion, to reduce the purpose of nitrogen oxides

二、with SCR on the boiler tail heating surface transformation, select the SCR catalyst for the temperature range (320-400 ℃), while free to meet the furnace or furnace denitrification required location space. The main means for the transformation of economizers and air preheater, as the original boiler design tail heating surface are relatively compact, so the main purpose of economizer transformation to make room. There are two main ways to transform the economizer: 1, directly draw the economizer out of the tail flue, placed in below of SCR reactor; 2, By the transformation into the H-finned tube or spiral finned tube to compress the space and move the economizer or air preheater properly.

With the furnace outside the SCR also need to design leads, lead back flue,  there are questions needed to notice is the flue gas flow rate and lead flue gas flow problem.

2, Denitrification enamel tube air preheater technology

SO2 can be oxidized by O2 in the air via catalyst and a certain temperature, that is, under the action of the catalyst active component V2O5, SO2 to SO3 conversion rate will increase correspondingly in the denitrification process, the NH3 escape is an objective existence, It in the air preheater in the lower layer and SO3 to form ammonium hydrogen sulfate, the reaction is as follows:

NH3 + SO3 + H2O → NH4HSO4

SO3 and the moisture in the flue gas generate sulfuric acid. Escape (escape) ammonia and sulfuric acid reaction to produce ammonium sulfate or ammonium sulfate. At different temperatures, ammonium sulfate were gaseous, liquid, granular. For coal-fired units, flue gas in the high ash content, hydrogen sulfate in the temperature range of 150 ~ 220 ℃ for the liquid, the lowest air preheater is just in this temperature range, it must take measures to prevent corrosion.

Based on the characteristics of flue gas after denitrification, our company  researched and developed enameled tube air preheater to solve the denitrification after the flue gas corrosion, plug problem. The glaze is new type of material with characteristics of anti-high temperature,anti-corrosion,anti-abrasion formulated by new scientific formula. Then evenly coated on the inner and outer surfaces of thin-walled steel pipes, and then sintered into composite enamel tubes at high temperatures. The enamel pipe preheater is arranged in the same way as the original, and the side of the flue gas and the air side are basically the same. After running, the enamel tube surface is smooth, not easy to block the ash, heat transfer effect enhanced. Inside (outside) coated enamel wear resistance, resistance to erosion, acid and alkali corrosion.

3, other

There are various situation during boiler operation, our company will develop technical solutions based on the actual operation of the boiler and arrange experienced professional engineers to optimize the combustion adjustment, and achieve implementation of the final technical transformation effect.