A hydrogenation coupling process for producing low-condensation-point diesel oil

Abstract

The invention discloses a hydrogenation coupling process for producing low-condensation-point diesel oil. A diesel oil raw material enters a hydroisomerization pour point depressing reactor after hydrofining, and a material passing through a first hydroisomerization pour point depressing catalyst bed layer is divided into two streams; one material stream enters a gas-liquid separator to be separated, the obtained liquid is extracted out of the reactor and mixed with hydrogen, and the mixture is subjected to a hydrogenation pour point depressing reaction; the other material stream is a mixturestream of gas in the reactor and residual liquid after extraction, and the mixture flow continues flowing through a second hydroisomerization pour point depressing catalyst bed layer; and a hydroisomerization pour point depressing reaction product and a hydrogenation pour point depressing reaction product are subjected to separation and fractionation separately to obtain diesel oil products with different specifications and low condensation points. The invention provides the hydrogenation coupling process for simultaneously producing more than two diesel oil products with different specifications on a set of hydrogenation process equipment for the first time, heat carried by part of isomerization pour point depressing materials can be fully utilized, and coupling operation of the hydroisomerization pour point depressing reactor and a hydrogenation pour point depressing reactor can be realized.

Description

technical field [0001] The invention belongs to the field of petroleum refining, and in particular relates to a hydrogenation coupling process for flexibly producing low-condensation-point diesel products. Background technique [0002] The increasingly stringent environmental protection regulations require higher and higher quality diesel products, mainly due to the increasing restrictions on sulfur content, cetane number, density and polycyclic aromatic hydrocarbon content. Low-quality diesel hydro-upgrading technology can greatly reduce the sulfur content and aromatics content of diesel products, reduce density and increase cetane number. In addition, in winter, diesel products in cold regions have different restrictions and requirements on the freezing point. According to the freezing point, diesel products in my country can be divided into 5#, 0#, -10#, -20#, -35# and -50 # and other different specifications. Hydrogenation decondensation technology can effectively reduc...

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Problems solved by technology

[0003] Distillate fraction hydroisomerization depreciation technologies, such as CN1718683A and CN1712499A, etc., use hydrofinishing catalysts and hydroisomerization depreciation catalysts containing zeolite β, and adopt a series of processes to produce diesel products, but under the same hydro-upgrading conditions The cetane number is lower than that of hydrogenated diesel oil, and the process conditions for the same low-condensation-point diesel products are harsher than those of hydrogenated decondensation process

[0004] Distillate fraction hydrotreating and depreciating technologies, such as CN102051232A and CN1257107A, etc., use hydrorefining catalysts and hydrotreating depreciating catalysts, and adopt a series of processes to produce low-condensing point diesel products, but the yield of diesel products is low

CN102453531A, CN103805258A and CN103805254A all alternately use hydrotreating catalysts and hydrotreating pour point depressing catalysts to obtain diesel products with low freezing point, but the yield of diesel oil is also low, and only one kind of diesel product can be produced

[0005] Using the hydrogenation technology CN105087063A, after the diesel fraction undergoes hydroisomerization and decondensation, the reaction heat is used to directly undergo hydrogenation and decondensation to produce low-condensation diesel products, but this process can only produce diesel products with one condensation point specification

[0006] To sum up, the existing hydroisomerization pour point depressing technology can greatly reduce the freezing point of diesel products, which can meet the index requirements of low freezing point diesel, but the yield is low when producing low freezing point diesel products

The existing hydrogenation decondensation technology can greatly reduce the freezing point of diesel products, which can meet the index requirements of low-condensing diesel, but the yield of diesel is low, usually less than 90m%, and the quality of diesel products is not greatly improved. When high cetane number n-paraffins are cracked into gas or naphtha fractions, the cetane number of diesel products will be reduced

Single product when using coupled hydrogenation technology

There is only one kind of diesel product produced by the above process technology, and the product flexibility is poor

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