(Texaco Stage 4 Flash) Vacuum flash separation tank level control
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During operation, the liquid level in the second vacuum flash separation tank is often high. What are some effective ways to lower this level? ?
In the second vacuum flash tank, the sludge water is pumped and sent to the sedimentation tank via control valves. If the liquid level does not drop, check the performance of the pump as well as the setting of the liquid level control valve. In some plants, the sludge water pump is not in use; the liquid level can still be maintained relying solely on the pressure difference.
Due to the slight negative pressure in the second vacuum flash tank, vapor cavitation occurs in the pump; as a result, no measurement can be taken and the liquid level cannot be lowered. We tried to reduce the negative pressure in the tank, but with little success. Hehe… The person above mentioned relying on pressure differences – could that damage the vacuum level in the vacuum tank? ? ?
The temperature of the flash tank should be around 50 at most. Are you controlling the vacuum level too high? We generally do not use injected steam; a vacuum level of -60 to -90 is sufficient to meet the production requirements. Also, this is related to the equipment layout.
Well, yeah, the main indicator is to keep the water temperature in the vacuum sedimentation tank below 60, right?
Our plant uses two-stage vacuum flash evaporation; the outlet temperature of the vapor from both stages is 60°C, and the temperature of the black water flowing at the bottom is also 60°C. Is this temperature level considered normal? At the same time, due to the vacuum pump and the suction effect, the negative pressures in both sections remain roughly at the same level of around -70 KPA. As a result, the liquid level in the flash separation tank in Section 1 keeps from dropping, while the separation tank in Section 2 can discharge liquid normally; the drainage in both the upper and lower sections operates properly. (This occurred after the pressure was increased in the vaporization system; at that time, the temperature and pressure in the high-flash system rose slightly.) I would like to ask the experts: in cases where negative pressure cannot be adjusted, what methods can be used to ensure the stable operation of the true flash system?
A few questions: first, the vacuum level during evaporation; second, the drainage volume and temperature; and also the performance of the pump as well as the pipes
Reply to 6# wut2ingzhi: Check whether the vacuum in the upper and lower sections is interconnected, and also inspect the vacuum pump and steam extraction system