Discussion on the design of amine-based desulfurization systems in integrated refining and chemical plants
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In the design of integrated refining and chemical plants in recent years, whether they consist of a single series or multiple series, the amine-based desulfurization systems are arranged and managed in a centralized manner. Although hydrogenation and non-hydrogenation processes operate separately, there are still several points that warrant consideration: First, for hydrogenation processes, the amine-based desulfurization systems for recycled hydrogen, dry gas, and liquefied gas should be differentiated based on the characteristics of each process. Slurry bed, fluidized bed, and trickle bed reactors present issues related to contamination of the amine solution by coke powder, catalytic powder, and elemental catalysts; in particular, the amine system used in slurry bed reactors needs to be carefully evaluated, and it is preferable that it be separate from the hydrogenation solvent regeneration system. What is the fate of the contaminated solvents generated by the hydrogenation process? How to preprocess (pre-filtering/fine filtering). II. Non-hydrogenation type: The flare gas recovery gas is the most complex type – it is in large quantities and contains oxygen, organic oxides, etc. This constitutes the biggest problem regarding solvent deactivation. Using the same regeneration system for both the solvents and the non-hydrogenation process is definitely the biggest mistake in the overall process; it is difficult to reactivate solvents that have become deactivated, and this has already led to serious problems such as foaming and corrosion in the latest integrated plants. With the development of non-hydrogenation process technologies, particularly the use of new additives, the potential problem of solvent contamination is significant and should be identified and addressed separately. Integrated plants take into account periodic maintenance, often establishing interconnections between hydrogenation units as well as between non-hydrogenation and hydrogenation units. Pollution issues across the entire system become prominent; therefore, for the amine liquid systems in such plants, it is recommended to adopt a approach of centralized layout and management, alongside decentralized control and separate handling. For special systems such as flare systems, separate recycling processes should be implemented to prevent harm to the entire system and to avoid creating endless risks related to processes and equipment.
In the design of integrated refining and chemical plants in recent years, the amine-based desulfurization systems have generally adopted a centralized layout and management approach. However, there are some issues related to hydrogenation and non-hydrogenation processes that merit discussion: I. Hydrogenation type: 1. In different hydrogenation processes (such as slurry bed, fluidized bed, and trickle bed), the problem of amine solution contamination (such as coke powder, catalytic powder, and elemental catalysts) is quite significant. In particular, the slurry bed amine solution system is recommended to be independent of the hydrogenation solvent regeneration system. 2. It is necessary to consider the disposal method for the solvents generated during the hydrogenation process, as well as the methods of pretreatment (primary filtration/fine filtration). II. Non-hydrogenation type: 1. Flame gas recovery gas represents the most complex issue in the non-hydrogenation type; it contains oxygen, organic oxides, etc., which have a significant impact on the stability of solvents. Therefore, using a common regeneration system for flare gas recovery gas and non-hydrogenation processes was a major mistake, which can lead to rapid deactivation of the solvent, difficulty in reactivating it, and even corrosion issues. 2. The development of non-hydrogenation process technologies, particularly the use of new additives, increases the potential risk of amine solution contamination, and it is necessary to identify this issue and take targeted measures. 3. When considering series maintenance, integrated plants feature interconnections between hydrogenation and non-hydrogenation processes, as well as among different hydrogenation series. At this time, the problem of system-wide pollution may become more prominent. Therefore, for the amine liquid system in integrated plants, based on centralized layout and management, it is recommended to adopt methods of separation, division of control, and decentralized control. Special cases such as flare systems should be subjected to separate recycling processes in order to avoid harming the entire system and to reduce potential risks related to processes and equipment. .
Thank you for sharing; this is an issue related to integrated design