Distillation column

2014-12-19 17:51:50 点击数：

Product advantages: Under certain conditions, packed towers have the outstanding advantages of small pressure drop, high operating flexibility, large production capacity, and small liquid holding capacity. However, some packings have higher cost and are sensitive to initial distribution. The separation efficiency and flux under high pressure are generally much lower than under normal or reduced pressure;

Relatively speaking, the plate tower has a simple structure, is easy to enlarge, and is low in cost. For atmospheric and pressurized systems, especially large tower diameters and multi-side gas-liquid mass transfer equipment, the plate tower has greater advantages and has relatively mature experience in operation and design. Therefore, the development and research of plate towers still plays an indispensable role in tower technology. The different types of plate towers lie in the different tray structures. The main common types are: bubble cap tower, sieve plate tower, float valve tower, tongue tower, etc. The plate bubble tower is the earliest plate tower used in industry, and it has been a popular tower type among plate towers for a long time. Comparison of various plate towers is a very complex issue. However, in terms of production capacity, tray efficiency, operating flexibility, pressure drop, and cost, the float valve tower has obvious advantages over the bubble cap tower in terms of steam load, operating flexibility, and tray efficiency, so it is currently widely used. The sieve plate tower has small pressure drop, low cost, and large production capacity. Except for its small operating flexibility, the rest are close to the float valve tower, so it is widely used.

The packed tower is a differential contact type gas-liquid mass transfer equipment. The packing in the tower is the basic element for gas-liquid contact and mass transfer. The liquid flows from top to bottom in the form of a film on the surface of the packing, and the gas flows in a continuous phase from bottom to top in counter-current flow with the liquid, and mass transfer and heat transfer between the gas and liquid phases are carried out. The concentration or temperature of the two phases changes continuously along the height of the tower. The main components include tower body, packing and support, liquid distributor and redistributor, demister, etc. Packing is the core internal component of the packed tower, which provides a surface area for the gas-liquid phase to fully contact for heat and mass transfer. It can be divided into two categories: bulk packing and structured packing. Bulk packing refers to packing that is mainly piled randomly. This kind of packing is particles with a certain shape, also known as granular packing. In a tower with randomly piled bulk packing, the flow paths of the gas and liquid phases are random. In addition, it is difficult to achieve uniformity everywhere when filling the packing, so it is easy to produce channeling and other undesirable situations, thereby reducing the efficiency of the tower. Structured packing is a type of packing that is neatly stacked according to uniform geometric patterns in the tower. The gaps are large, so the production capacity is large and the pressure drop is small. Due to the regular flow channels, as long as the initial distribution of the liquid is uniform, it will be uniformly distributed throughout the tower. Therefore, structured packing has almost no amplification effect and has high mass transfer efficiency. The types of structured packing can be divided into wire mesh corrugated packing and plate corrugated packing according to the structure. When used, according to the structural size of the packing tower, it can be stacked into a cylindrical block and placed in the tower, or divided into cylindrical blocks and assembled in the tower.