Device and method for producing high-pressure or super high-pressure steam as byproduct from maleic anhydride producing device

A method for producing high-pressure or super high-pressure steam as a byproduct from a maleic anhydride producing device, comprising the following steps:

• a) heat recovery from low-temperature process gas:
• boiler feedwater passes through a shell pass of the switching cooler and is heated by low-temperature reacted process gas in a tube pass;
• b) boiler water pressure boosting:
• the pressure of boiler water flowing out of the switching cooler is boosted by using the boiler water booster pump high enough to enter the super high-pressure steam drum;
• c) heat recovery from high-temperature process gas:
• the boosted boiler water is conveyed into the gas cooler and heated by high-temperature process gas at the outlet of the oxidation reactor;
• and
• d) generation of high-pressure or super high-pressure steam:
• the heated boiler water enters the super high-pressure steam drum and then enters the molten salt coolers, and the generated high-pressure or super high-pressure steam is separated from a liquid phase in the drum and flows out;
• wherein in step a), the temperature of boiler feedwater entering the switching cooler is less than or equal to 125° C.;
• the pressure of the boiler feedwater entering the switching cooler is less than or equal to 4 MPa;
• and the temperature of process gas entering the switching cooler is 240-300° C.;
• wherein in step b), boiler water enters the boiler water buffer tank or the high-pressure deaerator before being boosted by the pump;
• the operating pressure of the boiler water entering the boiler water buffer tank is less than or equal to 3 MPag;
• and the operating pressure of the boiler water entering the high-pressure deaerator is 0.3-2.0 MPag.