Daily question in the tower equipment technology exchange area – participate in the prize-winning activity! (02.06)

Regeneration is carried out in two stages using two independent regenerators. The previous regenerator operates at a high CO/CO2 ratio.

The hydrogen production plant’s CO2 removal absorption tower features two stages of absorption and two stages of regeneration. The upper part consists of a magnetic ring, while the lower part features a double overflow sieve plate. The overall structure of the regeneration tower is that of a tower body; the upper section of this tower body is the exhaust section. A corrugated water collection plate is installed between the exhaust section and the tower body, and they are connected using flanges. An exhaust fan is placed at the bottom of the tower body. The interior of the tower is filled with hollow polyhedral packing balls. The air inlet at the bottom of the tower is in the form of louvered grilles distributed evenly around the perimeter. The side walls of the tower body are equipped with multiple feeding holes as well as discharge holes

The absorption tower shares many similarities with the regeneration tower: both use Pall ring packing, have gas-liquid distribution plates above the packing layers, and have identical packing support ring structures. The difference is that the diameters of the upper and lower sections of the CO2 removal absorber are different, with the diameter increasing below the feed point for the semi-poor liquid. The rich liquid feed inlet at the top of the CO2 regeneration tower is equipped with three layers of circular bubble trays, while the top of the absorption tower has one layer of foam breaker mesh.

The absorption tower shares many similarities with the regeneration tower: both use Pall ring packing, have gas-liquid distribution plates above the packing layers, and have identical packing support ring structures. The difference is that there is a foam breaker mesh at the top of the absorption tower. The regeneration tower has three sections of packing, along with a reboiler for desorption and temperature elevation. Due to differences in operating pressure, the design pressures of the two towers vary significantly; the desorption tower is intended to produce carbon dioxide.

The structural similarities and differences between the CO2 absorption tower and the regeneration tower are as follows: 1. The structure of the CO2 absorption tower is simpler than that of the regeneration tower; generally, there are 46 trays in the CO2 absorption tower, while there are around 67 trays in the regeneration tower. 2. The structure of the CO2 absorption tower is simple, resulting in less metal usage and lower construction costs； The gas pressure drop is low, and the production capacity and plate efficiency are higher than those of a bubble column. The main drawback is the limited operational flexibility. The regeneration tower is a floating valve tower with dual overflow design, offering high production capacity ； High operational flexibility ； High tray efficiency ； The gas pressure drop and the liquid level difference are small ； The cost of the tower is low.

The absorption tower is a pressurized absorption device. Due to the use of two-stage absorption, only one-fourth to one-fifth of the total amount of solution enters the upper tower; moreover, most of the carbon dioxide in the gas is absorbed in the lower part of the tower. As a result, the entire tower is divided into an upper and a lower section: the upper tower has a smaller diameter while the lower tower has a larger diameter. The entire tower is filled with packing. To ensure uniform wetting of the filler surface by the solution, in addition to a liquid distributor installed at the top of the filler layer, the fillers in both the upper and lower columns are divided into two layers, with no liquid redistributor in the middle of each layer. Each layer of filler is placed on a support plate, which is specially designed and known as a gas-jet type support plate. The support plate is corrugated and features long circular holes on it; the cross-sectional area of these holes can be comparable to that of the tower. Gas enters the packing through the holes on the top and sides of the corrugations, while liquid flows out through the holes at the bottom of the corrugations. In this way, the gas-liquid distribution is even, flooding is less likely to occur, and it has good rigidity as well as a high load-bearing capacity. An antifoamer is installed in the liquid storage section at the bottom of the lower tower to eliminate the foam formed in the liquid flowing out of the packing layer. To prevent the solution from forming vortices that carry gas into the regeneration tower, a vortex breaker is installed on the rich liquid outlet pipe at the lower part of the absorption tower. The overall structure of the regeneration tower consists of a tower body. The upper part of the tower body is the exhaust section; a corrugated water-trapping plate is installed between this exhaust section and the tower body, with flanges being used for connection. An exhaust fan is placed at the bottom of the tower body, and the interior of the tower is filled with hollow polyhedral packing balls. The air inlet at the bottom of the tower is in the form of louvered grilles distributed evenly around the perimeter. The side walls of the tower body are equipped with multiple feeding holes as well as discharge holes.