What are the emergency measures if the deoxygenated water supply to the steam generator at the bottom of the distillation column in the hydrorefining unit is interrupted?
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The product coming out of the bottom of our distillation tower has a temperature of around 300°C; it is cooled by using a steam generator, with a steam generation rate of approximately 30 t/h. If the deoxygenated water supply is interrupted, do you know what technical modifications and measures can be taken as a contingency? The total amount of condensate produced by the unit is approximately 20 t/h. When this condensate is fed into the steam generator, the volume of water is insufficient; does this mean the steam generator needs to cool down and reduce its steam output? Do your systems have any other methods, such as technical upgrades or measures, to prevent interruptions in the deaerated water supply to the steam drum?
Providing the maximum amount of condensate water and adjusting the treatment capacity accordingly is the best way to maintain the operation of the system.
After the deoxygenated water supply is interrupted, the liquid level drops rapidly, causing the heating tubes of the heat exchanger to become exposed above the water surface. It is not possible to keep the heat exchange tubes underwater throughout the emergency process; in such cases, it is not feasible to adjust the liquid level, as this would cause thermal stress and lead to the rupture of the heat exchange tubes. The temperature of the deoxygenated water used to generate steam should be restricted; if the temperature of other alternative waters is low, it can cause cracks in the heat exchange tubes at the tube sheet (this has happened before). Therefore, the safest approach is to shut down the heat exchanger immediately after the supply of deoxygenated water is interrupted. Once the temperature of the heat exchanger drops, it should be cooled first and then heated again, in accordance with the operating procedures, so as to gradually restart the steam generation equipment. Otherwise, there is a high risk that more than half of the heat exchangers will be damaged. For your reference
In the event of a long-term interruption, any high-temperature water without oxygen will suffice, and condensed water can also be used temporarily.
1. Set up a bypass, 2. Set up an emergency water tank
Cut the cross-line, switch to air cooling, reduce the device’s capacity