Application of JKB/250Y filler

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Research and Application of JKB/250Y Packing as a Substitute for the Bubble Plate in the Debenzene Tower Wang Linfeng, Wang Yuhong (Pingmei Tianhong Coking Company, Pingdingshan 467021). In our company’s debenzene tower, the benzene content in the oil-rich stream is between 1.4% and 1.6%, which is far higher than the required level of 0.4% to 0.6%. As a result, the benzene hydrocarbon content in the gas coming out of the benzene washing tower remains high, which not only increases the impurities in the gas but also reduces the economic efficiency of the enterprise. Therefore, technical upgrades to the benzene removal tower are necessary to increase the yield of crude benzene. To this end, we used JKB/250Y packing in place of traditional bubble trays. 1 Characteristics of structured packing towers: Structured packing towers offer advantages such as high efficiency, low pressure drop, low liquid holding capacity, and high throughput; therefore, they are widely used in industries such as chemicals, petroleum refining, and light industry. The greatest advantage of replacing the bubble column benzene removal tower with a JKB/250Y packed tower is that it is not necessary to modify the tower structure; by making only partial changes to its interior, it is possible to increase production capacity. When installing the JKB/250Y packing, it should be arranged regularly inside the tower, with adjacent pieces of packing positioned at 90° to each other. The grid plate has sieve pores, and the flow channels of the filler are reasonably designed with a high porosity; this not only serves to cut and break up the dispersed phase but also plays a role in guiding and aggregating it ； Special arcs are designed around the filler, allowing it to fit well with the tower wall during installation and preventing wall flow and channeling ； As the fluid flows through the packing layer, it continuously reverses direction, achieving radial mixing and plunger flow; this reduces axial and radial backmixing and improves the mass transfer efficiency of the tower. The distillation tower is also equipped with separator components such as a liquid distributor and packing supports. 2 Modification Plan: The technical modification is carried out while keeping the outer diameter and height of the original benzene removal tower unchanged. The JKB/250Y packing is used to modify the internal structure of the tower, increase the recovery rate of aromatic hydrocarbons, and enhance the processing capacity of the benzene removal tower. (1) The stripping sections of layers 1 to 16 of the benzene removal tower still use bubble-cap trays, while the rectifying section employs two layers of JKB/250Y structured packing – 3 pieces per layer, each piece being 1300 mm in length. There is a packing support frame beneath each layer, and a packing holder is used above to control the height of the packing. The packing pieces are arranged at 90° to one another, and a gas-liquid distributor is used to redistribute the flow between layers. The distance between the packing in the top layer and the reflux distribution pipe is 800 mm. (2) The heat exchange area of the condensation cooler was increased from 80 m2×2 to 120 m2×2, and the original combined structure of the condensation section and the cooling section was changed to a separate installation for these two sections. This not only reduced the rise height of the oil-rich fluid and the cooling water but also lessened the workload on the transfer pumps, while facilitating maintenance. (3) The steam flow rate to the regenerator was calculated; changing the bottom from flat to conical not only meets the production requirements but also helps to save steam usage. 3 Operational Performance Since the start of construction of the benzene removal modification system on June 16, 2007, its operational performance has been as follows: (1) The system meets the production requirements, operates stably, and the yield, quality, and recovery rate of the products all meet the design specifications. (2) The system makes full use of the existing tower structure, civil engineering framework, power supply, and other equipment, resulting in significant economic benefits. (3) The use of the JKB/250Y packing has enabled the company to accumulate extensive theoretical and practical experience. 4 Conclusions The use of the JKB/250Y mass transfer packing has addressed the challenges related to gas-liquid distribution, fluid dynamics, mass and heat transfer that arise when scaling up benzene removal systems. It has improved the quality and output of the products, **reduced production costs, and enhanced environmental protection levels. Moreover, through microcomputer-based automated control, the level of production technology has been greatly improved, yielding good economic and social benefits.