Have ultra-low emissions been achieved for catalytic cracking flue gas?

Achieving ultra-low emissions is possible; currently, the processes for desulfurization, denitrification, and dust removal are being continuously improved. It is relatively easier to achieve ultra-low emissions using dry or wet methods. However, this comes with increased investment and operating costs for the equipment. Moreover, every technology has its own limitations and drawbacks. In other words, the limitations of desulfurization and denitrification technologies mean that they have certain constraints when it comes to achieving ultra-low emissions – the best level that can be achieved is around 30 ppm. To reach 10 ppm, further modifications or upgrades are necessary. Furthermore, a drawback is that improving the technology itself has certain effects on the front or back part of the device; for example, to increase the denitration efficiency of an SCR, it is necessary to increase the amount of ammonia injected and the thickness of the SCR bed, which in turn leads to higher costs, issues related to ammonia leakage, corrosion caused by ammonium sulfate crystals, problems with bed pressure drop, and requirements for boiler modifications, among others. Wet flue gas desulfurization using EDV improves the desulfurization efficiency, but it requires an increase in the number of nozzles; the main issue is the resulting rise in equipment costs. As for the increase in salt-containing wastewater, it is negligible compared to the original levels. The problems that could not be solved before remain unresolved even with ultra-low emission standards. In my opinion, desulfurization, denitration, and dust removal technologies need further innovation at present; it is necessary to address issues related to long-term operation, and on these two bases, the challenge lies in balancing costs with emission standards. Personal opinion,