Can a temperature-reducing pressure regulator be used to lower the temperature?
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Process conditions: The heating equipment operates at 300°C and 13 MPa, with steam being used for heating. After the process stops, it is difficult to lower the temperature of the equipment; cooling can only occur naturally. The process engineering team proposed using a temperature reduction valve to increase the water supply to the boiler in order to cool the equipment. At the final stage of cooling, only boiler water is used, without high-pressure steam to assist in heat removal. Will a temperature reduction valve be sufficient for this approach? The process diagram is as follows
It is possible to reduce the temperature, but the boiler feed water must have both an inlet and an outlet. This allows heat to be carried away.
After cooling, the condensed liquid is normally designed to flow into the steam flash drum. It’s not clear whether it’s possible for this liquid to go directly into the boiler feedwater before reaching the flash drum. But don’t pressure reducers used for temperature reduction usually have a system for discharging condensed liquid? When the amount of water in the boiler increases, could this lead to water hammer or an excessive outflow of water from the delivery system? Can this heat-exchanged boiler water be fed into the flash system?
The key is to check the pressure of the condensate behind the reactor; if that pressure is too high, it may not be possible to send the fluid into the flash tank, and in that case it might need to be sent to a tank at atmospheric pressure.
I don’t think this is feasible: 1. Generally, boiler feed water in temperature and pressure reducers is equipped with atomization devices, and in the event of a pressure drop in the steam network, doing so might damage the valves and temperature and pressure reducers. 2. Under normal circumstances, the steam pipes are relatively thick, while the pipes for temperature and pressure reduction are thinner; as a result, it takes longer to add water in this case, which is not conducive to restarting the system. Moreover, if water is not drained thoroughly while driving, water hammer is likely to occur. 3. Under normal circumstances, the temperature of the water after temperature and pressure reduction is low; if it enters steam pipes or equipment, the rapid cooling of the equipment can lead to leakage points and damage to the equipment. 4. The water after temperature and pressure reduction usually has a high pressure, and poor control can easily lead to overpressure in the equipment and pipelines. In summary, the costs outweigh the benefits.