What is the temperature rise curve of the heating furnace during the start-up process of delayed coking wax oil?
Thread Content
What is the temperature rise curve of the heating furnace during the start-up process of delayed coking wax oil? Is it provided by the design institute? Or should we base it on experience?
Start-up heating speed: Raise the temperature to 150°C at a rate of 20°C/h and keep the temperature constant for 8 hours. Raise the temperature to 250°C at a rate of 30°C/h and keep the temperature constant for 6 hours. Raise the temperature to 350°C at a rate of 30°C/h and keep the temperature constant for 6 hours. Raise the temperature to 420°C at a rate of 30°C/h and keep the temperature constant for 4 hours. Raise the temperature to 460°C at a speed of 30°C/h, switch the four-way valve, and change the bottom feed. This is usually provided by the design institute. After starting work, it can be changed according to your own installation conditions. For example, try to arrange constant temperature at night, and do not arrange important steps such as temperature rise and heating.
At the beginning of the work, we always follow the normal operating procedures. In the future, if we have more experience, we can be less strict. As long as the water is dehydrated before 150 degrees during the heating process, it will be a great achievement.
Start-up heating speed: Before 250℃, heat up to 250℃ at a speed of 50℃/h and keep the temperature constant for 5 hours. Raise the temperature to 350°C at a rate of 40°C/h and keep the temperature constant for 5 hours. The temperature is raised to 450°C at a speed of 30°C/h without constant temperature. Directly switch the four-way valve, change the bottom feed, and quickly heat up to the production temperature.
The key is that after the temperature rises to 350°C, the wax oil begins to vaporize, and the residual oil also begins to undergo slight condensation and cracking reactions. The coke tower and fractionation tower preheat faster, the coke tower itself basically has the switching conditions, and the fractionation wax oil and diesel oil collection tanks begin to have liquid levels.； After the temperature reaches 420℃~460℃, in order to avoid coking in the oil rejection system, the four-way valve should be directly switched, the bottom feed should be changed, and the temperature should be quickly raised to the production temperature (about 10 minutes).
The heating furnace heating curve design institute will definitely provide it, but experience is also important. Before 380 degrees, the constant temperature time can be longer, and after 380 degrees, the constant temperature time should be shorter.