【Ten Years of Rapid Development in Chemical Processing Equipment】Mixed Feed Stirring Vessel for Ultra-Large Crude Oil Hydrogenation Slurry Bed Units from 1978 to 2021
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Witnessing the decade-long rapid development of chemical processing equipment, I praise the prosperity and strength of modern China. Wishing everyone a happy New Year, and may their families enjoy peace and good health. By contributing our ideas, we can create a more lively atmosphere for discussion; HaiChuan becomes even better with your participation. Everyone is welcome to join in the forum discussions more actively. ----------------------------------------------------- In November 2021, Tianhua Institute successfully commissioned a 580 m3 mixed-feed mixer for the 2×300 million tons/year slurry-bed residue hydrogenation units part of Zhejiang Petrochemical Co., Ltd.’s 40 million tons/year refining project. This mixer has been operating stably for over six months to date. This marks a complete success in the domestic production of the ultra-large vertical mixed-feed stirrer tank for the residue hydrogenation slurry bed unit, which is under the responsibility of Tianhua Institute – a tank with a diameter of 5 meters, a height of 38.5 meters, a stirrer length of 32 meters, and a weight of 280 tons.
The slurry-bed residue hydrogenation technology primarily utilizes the EST process developed by the Italian company Eni. This process features strong adaptability of raw materials and high conversion rates; it is suitable for high-temperature, high-pressure hydrogenation reactions of low-quality heavy oil/residues in the presence of hydrogen and a catalyst. It has significant advantages in the processing of low-quality heavy oils with high metal content, high residue levels, and high viscosity. The slurry-bed residue hydrogenation technology utilizing this process can achieve liquid product yields of up to 80%–90%. The mixed-feed stirrer tank, independently designed by Tianhua Institute, serves as the preceding unit equipment for the residue hydrogenation slurry-bed reactors and is capable of supporting the operations at the front end of 3 hydrogenation reactors. Its function is to thoroughly homogenize the fresh feed delivered by the heating furnace, the depressurized recycled material, and the solids with the catalyst, and then to pump this mixed material into the slurry bed reactor; its proper and stable operation is directly related to the functioning of the preceding stages of the plant as well as the entire installation.
Due to the complex operating conditions of mix-fed stirred-tank reactors, design parameters such as high temperature, pressure, exposure to hydrogen, and solid content pose significant challenges to the design and manufacturing of such equipment. To ensure effective mixing, the design team at Tianhua Institute undertook research and development efforts to innovate and apply a number of new technologies aimed at reducing the impact of mixing dynamic loads on the operational stability of the equipment. By using stress analysis techniques, they ensured that the structures in areas subject to high stress were sound and safe; moreover, they employed flow field simulation methods to further optimize the structure of the mixing blades. As a result, they were able to complete the design and manufacturing of the 580m3 mixing feed tank, which is a key component of this large-scale, custom-designed vertical mixing device – the slurry bed residue oil hydrogenation unit