Description of the sulfur recovery process flow

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The process flow description indicates that the H2S-rich gas coming from the acid gas removal unit, at 34°C and 98 kPaag, enters the combustion furnace (F05001). There, at 1000°C, it combines with hot air preheated to 233°C in the sulfuric acid condenser (E05005) to form a process gas containing SO2 components. The hot process gas exits the burner at around 975°C and is cooled to 421°C in the waste heat boiler (E05001). Before entering the SO2 reactor (R05001), a stream of hot air preheated to 233°C from the sulfuric acid condenser (E05005) is introduced. This hot air is added to increase the oxygen content in the process gas, improve the conversion rate of SO2 in the SO2 reactor, and cool the process gas to 409°C. In the SO2 reactor (R05001), the process gas containing SO2 passes through three catalyst beds, allowing at least 99.3% of the SO2 to be converted into SO3. Since this conversion reaction is exothermic, bed coolers were installed between adjacent catalyst beds to improve the conversion rate, using 62 bar steam from the steam buffer tank (T05002) to cool the process gas. The first bed cooler (E05002) cools the process gas from 503°C to 415°C℃ ； The second bed cooler (E05003) cools the process gas from 422°C to 380°C. Ultimately, in the process gas cooler (E05004) at the end of the SO2 reactor, the process gas is cooled to 290°C using the boiler feedwater from the steam buffer tank (T05002). Since the dew point temperature of sulfuric acid under this pressure condition is 249°C, ensuring that the temperature of the process gas at the reactor outlet is 40°C above this dew point temperature can prevent corrosion. The process gas exiting the SO2 reactor is mixed with microcrystals supplied by the atomization unit before being sent to the sulfuric acid condenser (E05005), thereby aiding in the condensation of acid mist within (E05005). In the sulfuric acid condenser, the acid mist generated by the hydration reaction in the process gas condenses, and the resulting sulfuric acid at 249°C can reach 98.0% wt. The acid mist in the process gas remaining after condensation is less than 10 vppm, meeting the emission standards, and it is released through the exhaust stack. The condensed sulfuric acid is sent to the sulfuric acid buffer tank (T05001). The sulfuric acid in the sulfuric acid buffer tank is pressurized to 0.3 MPag by the sulfuric acid circulation pump (P05001), and then cooled to 40°C by the sulfuric acid cooler (E05006) using circulating cooling water. A portion is sent directly out of bounds ； Another portion of sulfuric acid passes through a reflux line, where it mixes with the sulfuric acid at 249°C condensed in the sulfuric acid condenser to reach 70°C, and is then sent to the sulfuric acid buffer tank.