Switchable triple-effect evaporator for styrene co-production epoxypropane device

The utility model provides a switchable triple-effect evaporator for a styrene co-production epoxypropane device, which comprises a first evaporator, a second evaporator and a third evaporator, the first evaporator, the second evaporator and the third evaporator are respectively provided with a shell pass and a tube pass, a production wastewater pipeline is connected with the upper part of the shell pass of the first evaporator, and a production wastewater pipeline is connected with the lower part of the shell pass of the second evaporator. A steam pipeline is connected with the tube pass of the first evaporator, a first water inlet valve is arranged at the end, close to the first evaporator, of the production wastewater pipeline, and a first steam valve is arranged at the end, close to the first evaporator, of the steam pipeline. According to the utility model, the first evaporator or the second evaporator or the third evaporator with faults in the system can be cut out without influencing the normal operati