Application of efficient and environmentally friendly plastic packing support grid

Application of efficient and environmentally friendly plastic packing support grid

In the semi-water gas of the nitrogen fertilizer plant, the coke oven gas of the coking plant and the city gas and industrial gas with coal as raw material, the gas cooling, dust removal and the removal of hydrogen sulfide in the gas are required. The packing tower, as a traditional packing tower, generally uses the wooden grid packing, which has a short life, and is thicker, small specific surface area, small void ratio, and unsatisfactory mass transfer effect. Coupled with the rough surface of the grid, the sulfur paste is easy to deposit on the surface of the packing tower, and because ordinary wood can not withstand high temperature and high humidity, the wooden grid packing must be made of northeast red pine after defatting treatment. The state has strictly controlled the amount of deforestation, procurement is difficult and the price is high, and it is urgent to replace the product. The plastic grille filler made of PVC, PP, etc., has large specific surface area, smooth surface, outstanding advantages such as large ventilation, pressure reduction and strong plugging resistance, low price, can be transformed at low cost to the old tower, and is a good substitute for wood grille filler. Plastic grille is processed from plastic profiles, does not cause environmental pollution, with this product instead of wood grille filler, can save a lot of wood, environmental protection, ecological balance has a positive significance, the technical identification experts of the National Science and Technology Commission suggested in the nitrogen fertilizer industry to promote the use.

The plastic support grid is composed of plastic plates, rods and tubes, which are assembled according to the size of the tower diameter and the entry hole after the processing plant, which is simpler to design and manufacture, and improves the utilization space of the tower. It is based on plastic sheet as the main mass transfer component, the plastic sheet is perpendicular to the tower section, parallel to the direction of air flow and liquid flow, the upper and lower layers are 45 degrees rotation, the air flow and liquid flow in the tower reverse rotation, swirl flow contact. The liquid falls along the surface of the grid by gravity, contacts with the rising gas, flows downward in a film-like manner on the surface of the plastic sheet, and the gas flows bottom-up as a frontier phase, and contacts with the liquid film to transfer mass, and droplets or film-like contact is formed between the gas and liquid, so the mass transfer effect is good and the absorption efficiency is high. The distance between the grid packing plates is large (generally 24~42mm), the void ratio is high, the specific surface area is large, the gas and liquid have a fixed direction, the channel of each layer of the plate is not uniform, with the increase of the gas volume or the amount of liquid, the effect of the gas and liquid two phases is enhanced, but the amount of hysteresis liquid is small, the resistance of the tower is very small, There is no phenomenon that the packing bed is full of liquid in the grid packing tower, so the plastic grid packing can be used to transform the old tower with a higher empty tower speed, which is 1.5 to 3 times that of the general packing. The production capacity is greatly increased, and the design of the new tower can reduce the diameter and height of the tower.

Due to the large distance between the grid packing plates, the surface of the plate is not smooth, the resistance of gas rising and liquid falling is greatly reduced, the gas and liquid have a fixed channel, and the fluid is constantly scouring contact between the plates, so that the dust-containing gas and liquid will not stagnate, deposit, silt and block on the surface of the packing. Therefore, plastic grille packing is a new type of structured packing with high efficiency, large flux, low pressure and no tower blocking. Under normal operating conditions, the flux is 80% higher than the plate tower. The use of plastic grid filler Zhejiang Juhua ammonia plant invested 200,000 yuan to replace its No. 3 desulfurization tower with polypropylene grid filler, after the transformation, the system resistance is greatly reduced, the desulfurization efficiency is increased from 94% to 97%, the tower is not blocked, the annual capacity is increased from 125,000 tons to 170,000 tons of synthetic ammonia, and the annual cost saving is nearly 150,000 yuan. Pingxiang Dier Chemical Packing Chemical Co., Ltd reformed the desulfurization tower, desulfurization efficiency increased by 5 percentage points, the first year of power saving 600 thousand kilowatts/hour, cost savings of 360,000 yuan, economic benefits are very considerable.