Problems with SCR and SNCR denitration technologies in domestic coking industries

One more question: How much is the investment required for SCR sulfur and nitrogen removal? What are the production and operation costs? How much extra cost will this impose on coking enterprises? With coking enterprises generally suffering losses, will the implementation of SCR for sulfur and nitrogen removal become the final straw that brings them to collapse?

Environmental regulations are becoming increasingly strict; key enterprises must be on the national monitoring platform. It’s necessary to install SCR systems, otherwise they will be shut down due to environmental regulations, and in severe cases, their owners may even face criminal liability!

It might eventually turn into a situation where going ahead doesn’t guarantee survival, but not going ahead definitely means death. This is also a form of screening for companies.

http://www.360doc.com/content/15/0730/00/21042880_488263683.shtml A summary of denitration technologies for coke oven flue gas. This might be helpful, but it’s not clear whether the data is accurate

The last edit to this post was made by angryant on 2016-7-31 at 09:40. Problems associated with SCR and SNCR technologies: SCR faces issues such as catalyst deactivation, HN3 escape, and further catalyst deactivation, while SNCR has the following problems: firstly, its nitrogen utilization efficiency is low; a large amount of nitrogen is necessary to achieve the reduction of NOX. This can easily lead to the escape of residual nitrogen, and the escape of ammonia further causes environmental pollution as well as the formation of ammonia salts that can clog or corrode equipment downstream ； Secondly, the N2O produced causes a greenhouse effect; numerous studies have shown that the amount of N2O generated using urea as a catalyst is much higher than that produced when ammonia is used as a catalyst ； Thirdly, if not controlled properly, the use of urea as a reducing agent can result in higher levels of carbon monoxide emissions. This is because at low temperatures, urea tends to be sprayed into the high-temperature air streams within the furnace, causing a quenching effect that affects the combustion process and thus increases carbon monoxide emissions. Fourth, when the temperature of the boiler superheater exceeds 800°C, injecting a low-temperature urea solution into the furnace chamber prevents further combustion of the hot coal, resulting in fly ash and a reduced combustion rate of carbon. Fifthly, corrosion occurs on the water-cooling walls of the nozzles. In SNCR injection systems, high-pressure steam generated on the furnace side is used as the atomization medium. When the pressure of this atomization steam reaches 0.6–0.9 MPa, the injector is connected to the nozzle via threads. Urine solution drips intermittently near the injector and at the location above the nozzle; when these urine drops fall onto the water-cooling wall beneath the injector, they form a continuous liquid film. Due to the high temperature inside the furnace, the water in this liquid film evaporates, increasing the concentration of ammonium produced by the decomposition of urea, which further accelerates the corrosion of the water-cooling tubes and ultimately leads to leaks.