Steam injection boiler is one of the main power and energy consumption equipments in oil thermal production. Generally, the high temperature saturated water enthalpy which is separated by the steam separator is used through the heat exchanger. However the water treatment system of the steam injection boiler is so simple and the separated saturated water is rich in calcium，magnesium and other ions which are easy to foul pipe surface and affects the heat transfer efficiency of the heat exchange equipment. Comparing with the case of no using the equipment, the screw expander which is of a selfcleaning ability recycled the waste heat of the saturated water, which can improve the thermal efficiency by 10.2% and save about 4.56×107 kW·h amount to 18 422.4 t of standard coal in the service period. The effect is significant.

The power plant boiler high temperature slag is typically the use of recycled water for cooling the slag, and recycled water slag wasted heat into the cooling tower and the atmosphere. Not only the heat of the slag has not been fully utilized, but also the boiler thermal efficiency and recycled water evaporation were caused by the waste of water resources to a certain extent, and by thermal pollution on the environment. It is very important that Boiler high temperature slag wasted heat recovery for energy conservation, and improved the overall boiler thermal efficiency. The design of the works of three waste heat recovery scheme, the effect of energy saving and economic benefits of each program optimization calculation resulted in cold slag recycling power plant boiler and high temperature slag wasting heat for heating boiler feed water, the cold residue machine released hot water into the low temperature heater between 7# and 8#, there are very significant results and thus reduce the turbine extraction, reduce the turbine power heat rate, and improve the efficiency of the entire power plant power generation. Its findings can be generalized to other power plant boilers and lowtemperature waste heat recycling.