Patented revolutionary technology. It circulates the system exhaust gas from the ESP outlet to the main process air, raises gas pressure and adds oxygen, then goes through the process of sulfur burning and conversion, sulfonation, and exhaust gas treatment. It manages to reuse the exhaust gas discharged from the ESP, and reduces the exhaust gas discharged to the atmosphere by 96% (meaning only 4% actual emission compared with the traditional process). Meanwhile, this process reduces the caustic soda unit consumption by 7kg on 100% basis, and 2-3kg sulfur.