How is the flow rate in the stripping tower controlled?
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For a stripping tower from which vapor is drawn on the pressurized side line of a single tower, how can the amount of acidic gas at the tower top and the amount of crude ammonia be automatically controlled? Is there a way to set the output flow rate to automatic?
In the past, for our acid gas system, temperature control was carried out in the middle of the filler; perhaps automatic mode was not used, and it’s not advisable to manipulate this valve casually. The side-line extraction control valve is operated manually; after a period of time, an extraction ratio is set based on quality considerations, and this ratio should be kept as low as possible.
In the past, the acidic gas control valve at the top of the tower was regulated based on the temperature in the middle of the packing section. Due to the lag in temperature changes, opening this valve too quickly could easily cause problems in the tower, and automatic control was not used. The side line is mainly used to control the side line extraction ratio; it should not be necessary to automate this process. The determination of the side-line extraction ratio is to keep it as low as possible while ensuring that the quality of the purified water meets the required standards. The actual side-stream extraction ratio remains constant over extended periods of time; for example, we kept it at 10% for over a year. There were also cases where it needed to be set at 12% or 15%, and in the case of 15%, this level was maintained for a long time as well.
I’m not quite familiar with the operations you’re referring to. But in the case of a stripping tower, controlling the flow rate at the top of the tower depends on the operating temperature at the bottom of the tower and the pressure at the top. As for the composition issue, it arises due to azeotropy. If separation is to be carried out under azeotic conditions, a condenser/cryocooler can be installed at the top of the tower; separation and reflux operations can then be carried out based on the temperature changes resulting from condensation. These are my suggestions