Multi-purpose furnace tail gas treatment process for metal heat treatment and nitriding

Absorb with sulfuric acid solution. Sulfuric acid solution is used to absorb ammonia gas to generate ammonia sulfate. Ammonia sulfate is an important fertilizer. When ammonia gas is absorbed again, the by-products can be put back into use while achieving environmental protection. However, for enterprises, purchasing sulfuric acid is a difficult problem, and sulfuric acid is also a considerable consumption.

Nitrogen oxides (NO) have a strong affinity for human hemoglobin, can squeeze oxygen out of human blood, and are exposed to nitrogen oxides for a long time. When the concentration exceeds 1.5mg / m3, humans can cause cancer. A large amount of nitrogen oxides can also cause photochemical pollution and cause great harm to living things. It can also cause acid rain and damage the ozone layer. The harm is higher than ammonia. National standards require far less ammonia than nitrogen oxides.

The nitriding multi-purpose furnace absorbs ammonia gas, the concentrated ammonia water enters the rectification column through the distillation tower, and is condensed and pressurized, and then stored and reused in an ammonia gas storage tank. This method is evolved from the ammonia synthesis process, which can not only ensure a large utilization of ammonia, but also prevent ammonia emissions from exceeding standards. However, there are many problems such as high equipment investment costs, high operating costs, uneconomical, hidden safety risks, and so on.

Metal nitriding treatment refers to a chemical heat treatment process that allows nitrogen atoms to penetrate into the surface layer of a workpiece at a certain temperature and in a certain medium. Nitrided products have excellent abrasion resistance, fatigue resistance, corrosion resistance and high temperature resistance. At present, the main process of domestic metal nitriding adopts a nitriding furnace. The ammonia gas is passed into a nitriding furnace. Under the condition of high temperature and lack of oxygen, the ammonia gas is decomposed into nitrogen and hydrogen, and the hydrogen is directly discharged, and the nitrogen penetrates into the metal to be treated. The decomposition rate of ammonia is generally between 15% and 30%. A large amount of unused ammonia is directly discharged. Ammonia is a colorless gas with a strong pungent odor. Irritating and corrosive effects. When ammonia