Contents
What is the effect of gas velocity on the pressure drop in packed column?
Points to note : – at constant liquid rate, gas pressure drop increases with gas velocity. – at constant gas velocity, the gas pressure drop is higher at larger liquid rate.
What happens when pressure drop increases?
The higher the pressure drop in the line, the greater the amount of energy consumed to maintain the desired process flow, requiring a higher horsepower motor. Conversely, the lower the pressure drop in a piping system, the less energy consumed, providing the potential to use a lower horsepower motor.
What is pressure drop in chromatography column?
Fluid flow through packed and open tubular chromatography columns requires a pressure difference across the column. In general, pressure drops are low if open tubular columns are used; significantly higher pressure drops are encountered with packed colnrnns.
What affects pressure drop in pipe?
Pressure drop increases proportionally to the frictional shear forces within the piping network. A piping network containing a high relative roughness rating as well as many pipe fittings and joints, tube convergence, divergence, turns, surface roughness, and other physical properties will affect the pressure drop.
What is flooding in a packed column?
Abstract: Packed column flooding is caused by an excessive liquid enters a packed column, leading to a significant increase in pressure drop, liquid hold-up, and loss in separation efficiency.
What is flooding in distillation column?
Flooding is a common abnormal process condition wherein the distillation column stops generating a separation, thus causing the quality of the top and/or bottom products to go off specification.
What is loading and flooding in packed column?
In the flooding, the gas phase prevents the flow of the liquid stream, causing it to drag along the top of the column. In the study, various combinations of flow rates are tested and the loading and flooding points.
What should be done to avoid flooding in packed tower?
Some of the more common methods used to eliminate flooding involve temporarily decreasing the feed rate, the reflux rate, or both, to reduce the amount of liquid in the column, and decreasing the vapour in the column by reducing the reboiler steam.
What causes a pressure drop in a column?
According to Ergun’s correlation, the parameters that affect pressure drop are particle diameter, flow velocity, interparticle porosity and column length. In order to create a significant pressure drop along the bed, a small particle diameter and a high gas velocity are used.
At higher gas rates, a portion of the energy of the gas stream is used to support an increasing quantity of liquid in the column. For all liquid rates, a zone is reached where pressure drop is proportional to a gas flow rate to a power distinctly higher than 2; this zone is called the loading zone.
What happens when the pressure drop reaches Point C?
As the gas velocity is increased further, the pressure drop increased. Some liquid started to be retained in the packings. When point c is reached, the quantity of liquid retained in the packed bed increases significantly.
Can a gas absorption column be above a loading point?
Operation of a gas absorption column is not practical above the loading point. For optimum design, the recommended gas velocity is 1/2 of the flooding velocity. Alternatively, some design can be based on a specified pressure drop condition, usually well below the pressure drop at which flooding would occur.