Questions about liquid holding capacity
Thread Content
Please give me some advice: For a pilot-scale packed tower device, how to evaluate the liquid holding capacity? For the same device, what is the change in liquid holding capacity under different liquid spray densities? Thank you in advance. . .
When the operating conditions at the top and bottom of the tower remain unchanged, the greater the spray density, the greater the liquid holding capacity. For reference only!
The greater the gas phase flow rate, the greater the liquid holding capacity. For the same device, the liquid holding capacity increases as the liquid spray density increases. There are certain limits for the gas phase and liquid phase flow rates, and liquid flooding will occur if the flow rate exceeds a certain limit.
The fixed tower device itself has requirements for liquid holding capacity. The air separation tower we build often maintains about 6%. If the operation of the bottom of the tower remains unchanged, as the density of the spray liquid increases, the liquid holding capacity will continue to increase until the air flow cannot pass through the liquid for heat exchange, which may cause the air flow to be unable to hold the liquid and cause liquid leakage.
The liquid holding capacity is divided into dynamic liquid holding capacity and static liquid holding capacity. The static liquid holding capacity should have nothing to do with the spray density and is determined by the packing and stacking method. The dynamic liquid holding capacity seems to be determined by the packing and gas speed.
If a general distillation tower can maintain a vapor-liquid balance, the liquid holding capacity of the wire mesh packing is about 6% of the packing volume. If the liquid floods, it will be greater than this value. Random packing filler is 10%.
There is no necessary relationship between spray density and liquid holding capacity, but the distribution effect is better； The liquid holding capacity is mainly related to the load of the gas and liquid phases. When the gas and liquid phases reach a certain load, there is basically no change in the liquid holding capacity before reaching the loading point of the packing. The resistance of the liquid phase to the gas phase is also very small, that is, the gas phase channel is very smooth and the gaps between the packings are still large. However, when the loading point is reached, the gaps will become very small and the gaps between the packings will also decrease rapidly. This will cause serious mutual obstruction between the gas phase and the liquid phase, resulting in serious flow obstruction, and ultimately lead to liquid flooding.