Tubular heat exchanger is one of the most widely used heat exchangers in chemical industry and alcohol production. It is mainly composed of shell, tube plate, heat exchange tube, head, baffle plate and so on. The required material can be made of ordinary carbon steel, copper, or stainless steel respectively. When heat transfer is carried out, a fluid enters the connecting pipe of the head, flows in the pipe, and flows out of the outlet pipe at the other end of the head, which is called the pipe path; Another fluid enters through the nozzle of the shell and flows out from another nozzle on the shell, which is called the shell path.