Let’s also talk about SSR

Thread Content

Leaving aside the processes and advantages, let’s talk about flue gas heat exchange. I’ve always had doubts regarding the use of heat from the exhaust flue of the tail furnace to preheat the reactor, as the tail furnace isn’t actually a stable heat source. The upstream section of the SSR is also a conventional Claus unit, which has strict requirements regarding the air-fuel ratio. When there are large fluctuations in the acidic gases produced by the refinery, it is easy for significant deviations to occur in the air supply (even the ratio analyzers installed in such units cannot maintain their accuracy over long periods of operation). Back-burning in the tail furnace is a common phenomenon, and the temperature in this tail furnace can sometimes reach thousands of degrees; therefore, it is necessary to have a high-temperature interlock system for this tail furnace. But recently I read a paper on the partial melting of the stainless steel heat exchange tubes in an SSR exhaust gas heat exchanger; the author attributed this to issues with the material of those tubes and recommended using 1Cr5Mo instead to improve their high-temperature resistance. I then wondered whether the SSR had an interlock mechanism to prevent excessive temperatures in the tail furnace. If such an interlock was not present or did not function, there were only a steam superheater and an exhaust gas heat exchanger behind the tail furnace; neither of these devices could help maintain a stable temperature. Moreover, the exhaust gas heat exchanger was designed to handle temperatures of around 400 degrees at most. In the event of severe overheating in the tail furnace, first, the exhaust gas heat exchanger would be unable to effectively divert that excess heat, leading to overheating of the hydrogenation reactor. Additionally, the heat exchanger itself could not withstand such high temperatures. The author suggests adding a bypass to this heat exchanger, to bypass it when the temperature is too high; this further increases the impact on the inlet temperature of the hydrogenation reactor. After installing the tail furnace in our facility, only steam superheating occurs. Various proposals were made during technical upgrades to recycle the heat from the flue gases, but these were rejected by the foreigners who did not recommend such recycling. If there are any mistakes in the above, please feel free to point them out. I am genuinely eager to exchange ideas with experienced colleagues regarding this manufacturing process, and I reject any attempts at deception. Those who need that paper please leave your email address.