Are there any particular considerations when setting the vapor pressure for dilution?
Thread Content
The process parameter for the diluted steam pressure in our unit is 0.67–0.72 MPa. What I would like to know is what considerations go into setting this value? What is the pressure of the dilution steam in each of your ethylene plants?
Generally, the design pressure for DS in ethylene plants falls within this range. If the pressure is set too high, the saturation temperature of DS increases as a result, which in turn affects the temperature of the quench oil and the temperature at the bottom of the quench tower. To maintain the temperature at the bottom of the tower, it is necessary to increase the flow rate of the quench oil, thereby increasing energy consumption. Therefore, during normal operation, as long as the DS flow rate required by the cracking furnace can be met, operators prefer to lower the DS pressure slightly. This reduces the saturation temperature of DS, which in turn lowers the temperature of the quench oil and reduces its flow rate, allowing the temperature at the bottom of the tower to remain constant and thus reducing the energy consumption of the quench oil pump.