In the power industry, in addition to the cooling of the generator shaft pump, the cooling of the transformer, the heating and cooling of the circulating water can be performed by plate heat exchanger, and steam exhaust generated by the power plant can be recycled and reused by welded plate heat exchanger or the plate-and-shell heat exchanger. The required high temperature and high pressure steam can also be generated by secondary heating and pressurization of the exhausted steam through the waste heat recovery system.
Applications:
In order to reduce energy consumption of the thermal power plant, the all-welded shell-and-shell heat exchanger is used as the condensate heater, and the waste heat of the flue gas recovered by the closed-type circulating water of the low-temperature economizer is fully utilized to heat the condensate in the boiler water inlet system. The low-temperature steam drawn from the steam turbine of the low-temperature heater is saved, so that more steam is used for the steam turbine to generate electricity. In the two 350MW unit boiler low temperature economizer system, the all welded plate and shell condensate heater is taken as an example.
Operating parameters:
| Medium source | Medium | Temperature℃ | Pressure Mpa | Flow Rate t/h |
| Low temperature Economizer | Recycled water | 115→75 | 0.4 | 570 |
| Cryogenic heater | Condensate | 38→110 | 4.6 | 296 |
Its heat recovery rate is 192GJ/h (about 6.5t equivalent to standard coal), which means it can save 6.5 tons of standard coal per hour.
Comparison between plate and shell heat exchanger(PSHE) between tube and shell heat exchanger(TSHE) as follow:
| PSHE | TSHE | |
| Heat transfer area | 1/3 | 1 |
| Floor area | 1/3 | 1 |
| Energy consumption | 3/4 | 1 |
| Cleaning frequency | low | high |
| Maintenance | easy | complicated |
| Investment | small | big |
In summer, the flue gas generated by the thermal power plant is about 130~140 °C. The low-temperature economizer heats the 75 °C economizer closed circulating water to 115 °C, the flue gas temperature is reduced to about 110 °C, and the desulfurization system is entered. The 115 °C economizer closed circulating water uses a fully welded plate-and-shell condensate low-system heater to heat the 38 ° C condensate to 110 ° C, and then condensate into the boiler feed water treatment system. In winter, the boiler flue gas is heated by a low-temperature economizer to heat the 70°C heat network water, which is heated to 110 ° C, and transported to the distribution through the hot water supply pipe station.