The temperature of the graywater deaerator in the water-coal slurry gasification unit experiences large fluctuations; what is the reason for the imbalance between the two deaerators operating in parallel?
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In Texaco’s water-coal slurry gasification process, the deaerators use low-pressure flash vapor and low-pressure steam to heat the ash water that is introduced. There are two deaerators operating in parallel, corresponding to seven high-pressure ash water pumps. Does the temperature of the deaerators, as well as any fluctuations in it, have a significant impact on the operation of the high-pressure ash water pumps?
I am not familiar with the Texaco water-coal slurry gasification process, so I will offer my personal opinions from the perspective of pressure balance only. 1. It is impossible to say that there is no impact at all: 1.1. Without considering fluctuations in the flash vapor, the parallel deaerators supply the pumps connected in parallel; differences in pipeline resistance and pump performance determine variations in the operating parameters of each pump. As long as these variations remain within the allowable operating range of the pumps, a static equilibrium can be achieved, and it is possible for the pumps to operate together despite their different operating parameters, which can be reflected in the flow rate or current of individual pumps. 1.2. When the difference causes the flow rate of the remote pump to drop to within the allowable operating range, it can lead to vibration in the pump. 1.3. The medium at the outlet of the deaerator is saturated; when the resistance in the pipeline from the deaerator to the remote pump is too high, the net liquid column height is not sufficient to meet the pump’s requirement for net positive suction head, which makes it easy for vaporization to occur at the pump inlet, leading to cavitation. This not only damages the pump but also exacerbates fluctuations in the operation of other pumps. 2. It’s not necessarily the case that this has an impact on the pump’s operation. 2.1. Generally, when designing such systems, operational characteristics are taken into account, and measures are taken to avoid unfavorable conditions. 2.2. As long as extreme unfavorable conditions do not occur, the static equilibrium mentioned in 1.1, along with the effects of flashing vapor fluctuations, ensures that the entire system remains in dynamic equilibrium. 3. Once the hardware of the system is determined, it is beneficial to avoid excessive fluctuations during operation
Is there any blockage in the water inlet of your deaerator, and is the amount of exhaust gas generated during operation high?