Negative-pressure crude benzene distillation process and equipment heating washing oil by steam

Abstract

The invention relates to a negative-pressure crude benzene distillation process and equipment heating washing oil by steam. Non-condensable gas of a debenzolization system is sucked by a vacuum pump or an ejector, so a debenzolization tower is in a negative-pressure operation state; washing oil is steamed, blown and regenerated by steam in a regenerator, and benzene homologs and derivates in the washing oil are steamed and blown by steam containing oil or fresh overheated steam obtained from the regenerator in the debenzolization tower. Compared with the prior art, the negative-pressure crude benzene distillation process and equipment have the benefits that (1) slagging of the washing oil is effectively prevented and the consumption of the washing oil is low; (2) the washing oil is heated uniformly by the steam, the amount of polymerized washing oil is small, the washing oil is regenerated by the overheated steam and accordingly the effective use of the washing oil is guaranteed; (3) crude benzene is distilled in a certain vacuum degree, the amount of steam used in the process is reduced by about 50%, the energy is saved, exhaust of tail gas is avoided and environmental protection is achieved; (4) the operation pressure in the debenzolization tower is moderate, the amount of condensed benzene in a separator is reduced, circulation of a large quantity of the benzene homologs and derivates between a crude benzene scrubber and the debenzolization tower is reduced, the treatment load of the equipment is reduced and the operation cost is reduced.

Description

technical field [0001] The invention relates to the technical field of recovery of coking chemical products, in particular to a crude benzene distillation process and equipment for steam heating and washing oil under negative pressure. Background technique [0002] At present, there are two crude benzene distillation processes in the coking industry: atmospheric pressure crude benzene distillation and negative pressure crude benzene distillation. [0003] The crude benzene distillation process at atmospheric pressure is mainly a steam stripping distillation process in which a tube furnace is used to heat the washing oil. This process is operated at a high temperature of 85-185°C, and requires a large amount of primary energy consumption (such as steam, coke oven gas, etc.). Each ton of crude benzene or light benzene needs to consume about 1000-1500kg of steam and 600-900Nm of gas. 3 / t crude benzene, the consumption of washing oil is about 100Kg / t crude benzene, and the ope...

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Problems solved by technology

This process has a high degree of vacuum and high operating temperature, which requires strong corrosion resistance of the equipment; at the same time, due to the high degree of vacuum, a large part of benzene will circulate in the benzene washing tower and the benzene removing tower after the vacuum pump, and the equipment treatment needs to be improved accordingly capacity, which increases equipment investment and operating costs; in addition, this process requires an additional part of the washing oil to be heated in the tube furnace, and the temperature of the washing oil after heating is relatively high, which increases the amount of slagging of the washing oil and increases the loss of washing oil ; At the same time, since this process does not use steam, it is difficult to regenerate residual oil, which will waste a certain amount of circulating oil washing and increase operating costs

[0006] In summary, the crude benzene distillation process at this stage has defects in washing oil consumption, operating costs, energy saving, etc., which need to be resolved urgently

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