Condensing steam turbine should also be equipped with condenser and vacuum pump vacuum system, usually supplied by the turbine host supplier package. The implementation of China's JB / T l0085--1999 "Turbine Condenser Technical Conditions" standard or the American Society for Heat Exchange HEl "steam cooler" standard. 1. Condenser pressure The pressure of the condenser depends on the temperature of the cooling water and is always greater than the saturated steam pressure corresponding to the cooling water outlet temperature. Condenser steam condensing temperature and cooling water outlet temperature difference is called the terminal temperature, terminal temperature is usually taken as about 5 ℃. JB / T l0085--1999 standard recommended cooling water inlet temperature 20 ℃, the condenser design pressure of 5 ~ 6kPa (A); cooling water inlet temperature of 25 ℃, the condenser design pressure of 6. 5 ~ 7.5kPa (A), which is mainly for power generation turbine condenser. Chemical pump, petrochemical industry cooling water inlet temperature is usually 32 ℃, the outlet temperature is usually 42 ℃, then the condenser pressure is usually 10 ~ 15kPa (A). To prevent the condenser condensate pressure set too high caused by increased consumption of steam. 2. Calculation of cooling water The amount of cooling water is calculated as follows: Q = G (IO-IC) = Wt (t2-t1) Cw where Q is the heat load of the condenser in kJ / h; Steam flow rate, kg / h; Io - enthalpy of steam entering the condenser in kJ / kg; Ic - enthalpy of condenser condensate, in kJ / kg; Wt - Cooling water flow, kg / h; t2 - cooling water inlet temperature, ℃; tl - cooling water outlet temperature, ℃; Cw-- specific heat capacity of cooling water, kJ / (kg · ℃). 3. Condenser Type Turbine condensers in industrial pumps are often surface-condensed and are rarely mixed so condensate can be recycled as boiler feedwater. Condenser for the horizontal shell and tube heat exchanger, water to go tube Cheng, steam shell process, both ends of the tube box, easy to clean the tube. Because the pump is usually spare,. The condenser does not have to be designed as a double chamber. The exhaust port (non-condensable) of the shell side should be located at the end of the steam flow. The lower part of the condenser with hot wells, hot wells should be set high and low level alarm to prevent condensate water occupy the heat exchange area or condensation pump cavitation. 4. Vacuum system The condensing turbine tail, condenser and connecting lines are operated under negative pressure. Although the vacuum system has been designed, manufactured and installed with sealing measures, it is inevitable that the trace air from the flange, the tube Joints and other leaks. In addition, although the boiler feed water after dehydration, but also dissolved trace non-condensable gas, with the steam into the condenser. These traces of air and non-condensable gas accumulate in the condenser after gradual accumulation, if not excluded, will form a great partial pressure, seriously reducing the condenser vacuum, deterioration of turbine performance, it should be set up aspirator. Aspirators are usually steam ejectors, aspirators often work as the main aspirator, are used two-stage extractor, an intermediate condenser between the two. Condensed water from the main condenser is often used as cooling water because it recovers some of the heat from the steam in the extractor and simplifies the system. Due to the use of the intercooling, the working steam consumption is less than the single stage extractor, and the economy is better. In addition, before the turbine starts, there is a lot of air in the system to be pumped away, and a start-up aspirator is also usually set up so as to establish a vacuum as soon as possible. Start aspirator are generally simple single stage suction device, its working steam is not recovered, and the extracted gas together to the atmosphere.