Design optimization of regenerative oxidation furnace (RTO)

Design optimization of regenerative oxidation furnace (RTO)
Volatile organic compounds (VOC) are important components of air pollutants. At present, the common VOCs treatment methods at home and abroad mainly include activated carbon pressure swing adsorption, photocatalytic oxidation, solution absorption and high-temperature oxidation. Among them, the high-temperature oxidation method is widely used because of its high efficiency in treating VOC waste gas. Regenerative oxidation furnace (RTO) is a popular high temperature oxidation treatment equipment for VOC waste gas at home and abroad. The mainstream RTO product is car tower RTO. The three box tower RTO furnace can meet the requirements of processing efficiency and economy. The mainstream three chamber RTO is applicable to VOCs purification with waste gas volume of 10,000~30,000 m3/h.
The working principle of the regenerative oxidation furnace is: firstly, the waste gas is preheated to a certain temperature through the heat accumulator, and then the organic molecules in the waste gas are oxidized and burned into carbon dioxide and water in the combustion chamber. The high-temperature gas generated by combustion flows through the heat accumulator again to heat the heat accumulator. This "heat accumulated" is used to preheat the new exhaust gas entering the furnace. The inlet and outlet air of the regenerator is continuously switched by the reversing valve to form a continuous working cycle.
RTO low nitrogen environmental protection technology
By analyzing the research on low nitrogen technologies by domestic and foreign scholars, the technologies that can be used to control NOx emissions on RTO can be divided into two categories: one is to control the generation of harmful NOx during combustion. The second is the technology to control harmful NOx emissions after combustion.
One method is to control the generation of harmful NOx during combustion. At present, a large number of technologies to control nitrogen emission in combustion process are widely promoted at home and abroad, which can be divided into low NOx burner technology and excessive air combustion technology. From the perspective of NOx generation mechanism, most NOx is generated during combustion. Technicians change the combustion conditions (usually the temperature conditions in the combustion area) and fuel supply during the combustion process by changing the structure of the burner, so as to achieve the purpose of controlling NOx generation. According to the influence of combustion conditions on NOx emission and the formation mechanism of NOx, researchers have improved the burner from several aspects, such as "gas classification, air classification, forming obvious combustion zone, and forming flue gas reflux", so as to reduce NOx emission. Heavy oil burners mostly use staged combustion technology, while gas burners mostly use premixed lean oil combustion technology. Compared with the latter premixed lean burn technology, they produce less NOx. During the use of low nitrogen burners, the characteristics of different combustion denitrification technologies are different, and the corresponding burner layout is also different.
Another denitration technology for combustion tail gas can be divided into wet denitration and dry denitration.
Dry denitration technology is a method to reduce NOx in waste gas to N2 or convert it to nitrate for recycling. At present, dry denitration technologies at home and abroad mainly include selective catalytic reduction SCR technology and non catalytic reduction SNCR technology. The principle of SCR technology is to use catalyst to reduce the temperature of redox reaction. The reduced N2 is pollution-free and has good treatment effect. The commonly used catalysts for SCR technology are V2O5 and MnO2. When selecting SCR catalyst, it is necessary to analyze the cause of catalyst poisoning caused by impurities in the gas and give reasonable consideration. At present, more durable catalysts are being researched and developed all over the world. The principle of SNCR technology is to directly inject reducing agent into the furnace without catalyst to decompose nitrogen in waste gas into N2 and H2O. The advantage of SNCR technology is less investment. However, its disadvantages are large ammonia consumption and low efficiency.
Wet denitration technology is a method that first converts nitrogen compounds into NO2, and then absorbs NO2 with alkaline solution. Normally, the equipment used to absorb NO2 is packed absorption tower. The wet denitrification process and equipment are simple, with low operation cost and no secondary pollution. According to different NOx treatment methods, the wet process can be divided into oxidation absorption method and complexation absorption method.
The integrated application of the above two technologies in RTO system design can effectively reduce nitrogen emissions and achieve the goal of energy conservation and emission reduction.