CN109988627B

CN109988627B - Flexible paraffin hydrogenation process

Info

Publication number: CN109988627B
Application number: CN201711471005.2A
Authority: CN
Inventors: 刘涛; 李宝忠; 姚春雷; 张艳侠; 黄玉洪; 方向晨
Original assignee: China Petroleum and Chemical Corp; Sinopec Dalian Research Institute of Petroleum and Petrochemicals
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2017-12-29
Filing date: 2017-12-29
Publication date: 2021-07-09
Anticipated expiration: 2037-12-29
Also published as: CN109988627A

Abstract

The invention discloses a flexible paraffin hydrogenation process. The paraffin raw material enters a hydrofining reactor, and the material passing through an upper hydrofining catalyst bed layer is divided into two strands; one material is pumped out of the hydrofining reactor through the middle of the bed layer and enters a hydroisomerization reactor to carry out an isomerization reaction; the other material continuously flows downwards through a hydrofining catalyst bed layer at the lower part; and respectively carrying out gas-liquid separation and fractionation on the obtained hydrofining reaction material and the hydroisomerization reaction material to obtain paraffin products with different specifications. The invention provides a hydrogenation process for simultaneously producing more than two paraffin products with different specifications on one set of hydrogenation process device for the first time, which can fully utilize the heat carried by partial hydrofining materials to realize the coupling operation of a hydrofining reactor and a hydroisomerization reactor.

Description

Flexible paraffin hydrogenation process

Technical Field

The invention belongs to the field of petroleum refining, and particularly relates to a paraffin hydrogenation process for flexibly producing high-quality paraffin products.

Background

Paraffin is a solid petroleum product obtained by solvent dewaxing and deoiling vacuum distillate oil, and is an important raw material for medicine, daily chemical industry and other fine chemical industries. The paraffin wax can be roughly classified into paraffin wax, high-melting petroleum wax, microcrystalline wax, and the like. The paraffin wax for the applications needs to be deeply refined to remove sulfur, nitrogen compounds and polycyclic aromatic hydrocarbon contained in the paraffin wax so as to be harmless to human bodies. The paraffin refining includes clay refining and hydrorefining, wherein the hydrorefining technology is a process of hydro-converting non-ideal components in raw materials under certain temperature, pressure, hydrogen and the presence of a catalyst. Compared with clay refining, hydrorefining has the characteristics of high product yield, good quality, no waste residue and the like, and is a main method for refining paraffin.

The paraffin hydrofining is to deeply refine a paraffin raw material under mild reaction conditions to effectively remove heteroatoms such as sulfur, nitrogen and the like and saturated polycyclic aromatic hydrocarbons. The hydrogenation technology of microcrystalline wax and mixed crystal wax is to process the high-quality microcrystalline wax and mixed crystal wax produced by refining deasphalted oil or heavy oil with solvent and dewaxing and deoiling, and even can reach the quality requirements of food grade and medicine grade. However, the paraffin refining method including common hydrofining has little improvement on the toughness of paraffin products, and hard paraffin has the defects of poor toughness, easy fragmentation and the like, so that the use effect of the hard paraffin in many fields such as moisture resistance, insulation, sealing and the like is influenced. CN1176296A, CN106433780A, CN001769395A, CN106398757A and the like all disclose a paraffin hydrofining method which can effectively reduce the impurity content and the content of polycyclic aromatic hydrocarbons of paraffin products, and CN100432193C discloses a paraffin hydrofining method which uses a catalyst containing isomerization performance to improve the toughness. However, the paraffin hydrogenation process can only produce one paraffin product, and has poor operation flexibility.

In summary, the existing paraffin hydrogenation technology can greatly reduce the contents of impurities such as sulfur, nitrogen and the like in paraffin products by a hydrofining method, reduce the content of polycyclic aromatic hydrocarbons, improve the properties of the paraffin products, and can also increase the content of isomeric hydrocarbons in the paraffin products by using an isomerization catalyst method, enhance the toughness of the paraffin products, and solve the problem of easy crushing, but only one kind of paraffin products is produced by the above process technology, and the flexibility of the products is poor.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a flexible paraffin hydrogenation process, namely, a part of reaction material flow is extracted from the middle part of a hydrofining reactor, and the paraffin raw material is subjected to hydrofining and hydroisomerization combined method to flexibly produce high-quality hydrofined paraffin products and hydroisomerization paraffin products.

The flexible paraffin hydrogenation process comprises the following steps:

a. passing the paraffin raw material through a hydrofining catalyst bed layer at the upper part of a hydrofining reactor under the hydrofining condition to obtain a first hydrofining material flow, dividing the part of the reaction material flow into two parts, and pumping one part of the reaction material flow out of the hydrofining reactor;

b. b, continuously allowing the rest part of the first hydrofining material flow in the step a to pass through a hydrofining catalyst bed layer at the lower part of a hydrofining reactor under the hydrofining condition, and separating and fractionating the hydrofining material flow to obtain a hydrofining high-pressure hydrogen-rich gas, a hydrofining gas product, a hydrofining naphtha product and a hydrofining paraffin product;

c. and b, allowing the first hydrofined material flow extracted from the reactor in the step a to pass through a hydroisomerization catalyst bed layer of the hydroisomerization reactor under the hydroisomerization condition, and separating and fractionating the hydroisomerization material flow to obtain a hydroisomerization high-pressure hydrogen-rich gas, a hydroisomerization gas, hydroisomerization naphtha and a hydroisomerization paraffin product.

The hydrofining process according to the present invention may further comprise a step d: and (c) mixing the hydrofining high-pressure hydrogen-rich gas obtained in the step (b) with the hydroisomerization high-pressure hydrogen-rich gas obtained in the step (c) for recycling.

S, N, O and other impurities in the paraffin raw material are effectively removed when passing through a hydrofining catalyst bed layer at the upper part of a hydrofining reactor, aromatic hydrocarbon is subjected to hydrogenation saturation to a certain extent, and when one part of a reaction material flow continues to pass through a hydrofining catalyst bed layer at the lower part of the hydrofining reactor, the hydrogenation reaction depth is deeper, so that the requirement of producing a high-quality paraffin product is met; after part of the first hydrofining material flow is subjected to hydrogenation isomerization catalyst, part of normal paraffin is subjected to isomerization reaction to obtain a high-quality paraffin product which is strong in toughness and not easy to break.

Compared with the prior art, the flexible paraffin hydrogenation process has the advantages that:

1. in the invention, the hydrofining reactor comprises at least two hydrofining catalyst beds. Through the hydrofining material extraction step arranged in the middle of the hydrofining reactor bed layer, effective distribution of hydrofining material strands can be realized without special operation, and the obtained materials are subjected to different hydrogenation processes, so that the target paraffin products with different specifications can be flexibly produced. At the same time, it is technically easy to extract the reactant stream in the middle of the reactor bed. In the prior art, a set of hydrogenation devices can only obtain paraffin products with one specification; if paraffin products with different specifications are required to be obtained, more than two sets of hydrogenation devices are required. Therefore, the invention provides a hydro-conversion process for producing more than two different paraffin products on one set of hydrogenation process device for the first time.

2. According to the method, the first hydrofining material flow extracting device is arranged in the middle of the catalyst bed layer of the hydrofining reactor, the first hydrofining material flow obtained by hydrofining the paraffin raw material is extracted out of the reactor and is sent into the independently arranged hydroisomerization reactor to carry out hydroisomerization reaction, and the content of the isomeric hydrocarbon of the hydroisomerization paraffin product is improved, so that the method can flexibly produce paraffin products with different isomeric hydrocarbons.

3. In the invention, the paraffin wax product obtained by hydrofining has high normal hydrocarbon content; the paraffin wax product obtained after partial hydrofining and hydroisomerization has high content of isomeric hydrocarbon; can respectively meet the requirements of producing high-quality paraffin products with different target indexes.

4. In the invention, the liquid obtained in the middle of the refined catalyst bed layer of the hydrofining reactor has very high temperature and pressure, and can directly enter a newly arranged hydroisomerization reactor for reaction, thereby fully utilizing the heat carried by the part of refined materials and realizing the coupling operation of the hydrofining reactor and the hydroisomerization reactor.

Drawings

Fig. 1 is a schematic flow chart of the principle of the present invention.

Wherein: 1-paraffin feed, 2-hydrofinishing reactor recycle hydrogen, 3-hydrofinishing reactor, 4-hydroisomerized feed stream, 5-hydrofinished stream, 6-hydrofinished high-pressure separator, 7-hydroisomerized reactor, 8-hydroisomerized stream, 9-hydroisomerized high-pressure separator, 10-hydrofinished stripper or fractionator, 11-hydroisomerized stripper or fractionator, 12-hydrofinished naphtha product, 13-hydrofinished paraffin product, 14-hydroisomerized naphtha product, 15-hydroisomerized paraffin product, 16-hydrofinished high-pressure separator gas product, 17-hydroisomerized high-pressure separator gas product, 18-make-up hydrogen.

Detailed Description

The raw paraffin oil in step a may include one or more of liquid paraffin, high melting point petroleum wax, microcrystalline wax, mixed microcrystalline wax or synthetic wax.

The hydrofining catalyst in the step a is a conventional paraffin hydrofining catalyst. The hydrogenation catalyst contains one or more of Co, Mo, W and Ni as hydrogenation active component in 5-70 wt% calculated in oxide, and the carrier of the hydrogenation catalyst contains at least one of alumina, amorphous silica-alumina, silica and titania and may contain other assistant, such as P, Si, B, Ti, Zr, etc. The hydrogenation catalyst can be a commercially available catalyst or can be prepared according to the existing method in the field. The hydrogenation active component is a catalyst in an oxidation state, and is subjected to a conventional sulfurization treatment before being used, so that the hydrogenation active component is converted into a sulfurization state. The commercial hydrogenation catalysts mainly comprise 481-2B, FV-1, FV-10, FV-20 and FV-30 catalysts which are developed by Fushun petrochemical research institute (FRIPP). The operation condition can adopt the conventional operation condition, generally the reaction pressure is 3.0MPa to 15.0MPa, and the volume space velocity is 0.2h^-1~6.0h^-1The average reaction temperature is 180-400 ℃, and the volume ratio of hydrogen to oil is 100: 1-1500: 1.

And c, the mass proportion of the part of the extracted material flow in the step a in terms of liquid phase to the raw oil is 5-95 wt%, and preferably 10-80 wt%.

The separation described in step b generally comprises separation of two parts, a high-pressure separator and a low-pressure separator for hydrofinishing. Wherein the high-pressure separator separates to obtain hydrofining high-pressure hydrogen-rich gas and liquid, and the liquid separated by the high-pressure separator enters the low-pressure separator. The low pressure separator separates the high pressure liquid product to yield a hydrocarbon-rich gas and a low pressure liquid product. The hydrocarbon-rich gas is separated to obtain the required hydrofined gas product.

The fractionation described in step b is carried out in a hydrofinishing stripper or fractionator system. And fractionating the low-pressure liquid product in a stripping tower or a fractionating tower to obtain a hydrofined naphtha product and a hydrofined paraffin product.

The hydroisomerization catalyst in step c is a conventional paraffin hydroisomerization catalyst, and generally takes a metal in a VIB group and/or a VIII group as an active component, wherein the metal in the VIB group is generally Mo and/or W, and the metal in the VIII group is generally Co and/or Ni. The carrier of the catalyst contains one or more of alumina, siliceous alumina and molecular sieve, preferably containing molecular sieve. The molecular sieve can be a beta type molecular sieve, a Sapo type molecular sieve and the like. Based on the weight of the catalyst, the content of the VIB group metal is 10-35 wt% calculated by oxide, the content of the VIII group metal is 3-15 wt% calculated by oxide, the content of the molecular sieve is 2-30 wt%, and the content of the alumina is 10-80 wt%. The main catalysts comprise FC-14, FC-20 and the like developed by the petrochemical research institute. For the hydro-upgrading catalyst, the isomerization reaction of straight-chain paraffin is mainly required, and the cracking performance is weak. The hydroisomerization can be carried out under conventional operating conditions, which are generally: the reaction pressure is 3.0-15.0 MPa, and the volume space velocity is 0.2h^-1~6.0h^-1The average reaction temperature is 180-400 ℃, and the volume ratio of hydrogen to oil is 100: 1-1500: 1.

The lower part of the hydroisomerization reactor in step c can be filled with a supplementary hydrofining catalyst, and the supplementary hydrofining catalyst can be the same as or different from the hydrofining catalyst in the hydrofining reactor. The volume space velocity of the hydroisomerized material passing through the supplementary hydrofining catalyst is 1.0h^-1~25.0h^-1The reaction pressure is 3.0-15.0 MPa, the average reaction temperature is 180-400 ℃, and the volume ratio of hydrogen to oil is 100: 1-1500: 1.

The separation described in step c is carried out in a hydroisomerization high pressure separator and a low pressure separator. Wherein, the hydroisomerization high-pressure separator separates to obtain hydroisomerization high-pressure hydrogen-rich gas and liquid, and the liquid separated by the high-pressure separator enters the low-pressure separator. The low pressure separator separates the high pressure liquid product to yield a hydrocarbon-rich gas and a low pressure liquid product. The hydrocarbon-rich gas is separated to obtain the required hydroisomerized gas product.

And c, fractionating in a stripping tower or a fractionating tower system, and fractionating the low-pressure liquid product in the stripping tower or the fractionating tower to obtain a hydroisomerized naphtha product and a hydroisomerized paraffin product.

The hydrofined gas product and the hydroisomerization gas product in the step b and the step c can be used as products independently or can be mixed into a mixed gas product.

The hydrorefined naphtha product and the hydroisomerized naphtha product described in step b and step c may be used as separate products or may be mixed as a mixed naphtha product.

And d, mixing the high-pressure hydrogen-rich gas in the step d, and then directly using the mixed gas as recycle hydrogen, or recycling the mixed gas after hydrogen sulfide is removed by a recycle hydrogen desulfurization system.

With reference to fig. 1, the method of the present invention is as follows: the method comprises the steps of mixing a paraffin raw material 1 with recycle hydrogen 2, enabling the mixture to enter a hydrofining reactor 3, extracting a hydroisomerized raw material flow 4 from a reactant flow passing through a first hydrofining catalyst bed, enabling the material flow after the hydroisomerized raw material flow 4 is extracted to continue to enter a subsequent hydrofining catalyst bed, enabling a hydrofining product flow 5 to enter a hydrofining high-pressure separator 6 for gas-liquid separation, enabling liquid obtained through separation to enter a fractionating tower 10 for fractionation to obtain a hydrofined naphtha product 12 and a hydrofined paraffin product 14, enabling the hydroisomerized raw material flow 4 to enter a hydroisomerizing reactor 7, enabling a product flow 8 passing through the hydroisomerizing catalyst bed to enter a hydroisomerizing high-pressure separator 9 for gas-liquid separation, enabling the liquid obtained through separation to enter a fractionating tower 11 for fractionation to obtain a hydroisomerized naphtha product 14 and a hydroisomerized paraffin product 15, and enabling the hydrofined naphtha product 12 and the, or mixed to obtain a mixed naphtha product, and the gas 16 obtained by separating the hydrofining high-pressure separator 6 and the gas 17 obtained by separating the hydroisomerization high-pressure separator 9 are mixed and then pass through a recycle hydrogen compressor to be mixed with make-up hydrogen 18 to be used as recycle hydrogen.

The embodiments and effects of the present invention are described below by way of examples.

Examples 1 to 3

The protective agents FZC-100, FZC-105 and FZC106 are hydrogenation protective agents developed and produced by the smooth petrochemical research institute of the China petrochemical industry, Inc.; the catalyst FV-10 is a hydrofining catalyst developed and produced by the smooth petrochemical research institute of China petrochemical company Limited; the catalyst FC-20 is a hydroisomerization catalyst developed and produced by the smooth petrochemical research institute of China petrochemical company Limited and contains a beta-type molecular sieve.

TABLE 1 Main Properties of Paraffin feedstock

TABLE 2 Process conditions

TABLE 3 test results

As can be seen from the examples, the hydrogenation process of the present invention can achieve the purpose of producing paraffin products with different normal hydrocarbon contents by extracting a part of reaction material flow from a hydrofining reactor and using a hydrofining catalyst and a hydroisomerization catalyst, and the production mode is flexible.

Claims

1. A flexible paraffin hydrogenation process comprising the steps of:

2. The hydrogenation process of claim 1, further comprising step d: and (c) mixing the hydrofining high-pressure hydrogen-rich gas obtained in the step (b) with the hydroisomerization high-pressure hydrogen-rich gas obtained in the step (c) for recycling.

3. The hydrogenation process of claim 1, wherein the paraffinic wax feed is selected from at least one of liquid paraffin, high melting petroleum wax, microcrystalline wax, mixed microcrystalline wax, or synthetic wax.

4. The hydrogenation process according to claim 1, wherein in the hydrofining catalyst, the hydrogenation active component is one or more of Co, Mo, W and Ni, and the carrier of the hydrofining catalyst contains at least one of alumina, amorphous silica-alumina, silica and titania; the weight content of the hydrogenation active component is 5-70% by oxide.

5. The hydrogenation process of claim 1, wherein the hydrofinishing conditions are: the reaction pressure is 3.0-15.0 MPa, and the volume space velocity is 0.2h^-1~6.0h^-1The average reaction temperature is 180-400 ℃, and the volume ratio of hydrogen to oil is 100: 1-1500: 1.

6. The hydrogenation process according to claim 1, wherein the withdrawn portion of the stream in step a is 5 to 95 wt.% of the feed in liquid phase.

7. The hydrogenation process of claim 1, wherein the hydroisomerization catalyst comprises a group VIB and/or group VIII metal as an active component, and the catalyst carrier comprises alumina and a molecular sieve, wherein the molecular sieve is a beta-type molecular sieve or a Sapo-type molecular sieve.

8. The hydrogenation process of claim 7 wherein the group VIB metal content, as oxide, is from 10wt% to 35wt%, the group VIII metal content, as oxide, is from 3wt% to 15wt%, the molecular sieve content is from 2wt% to 30wt%, and the alumina content is from 10wt% to 80wt%, based on the weight of the hydroisomerization catalyst.

9. The hydrogenation process of claim 1, wherein said hydroisomerization conditions are: the reaction pressure is 3.0-15.0 MPa, and the volume space velocity is 0.2h^-1~6.0h^-1The average reaction temperature is 180-400 ℃, and the volume ratio of hydrogen to oil is 100: 1-1500: 1.

10. The hydrogenation process of claim 1 wherein the hydroisomerization reactor is loaded at its lower end with a make-up hydrofinishing catalyst and the volume space velocity of the hydroisomerized material passing through the make-up hydrofinishing catalyst is 1.0h^-1~25.0h^-1。

11. A hydrogenation process according to claim 6, characterized in that the withdrawn partial stream in step a comprises 10 to 80 wt.% of the feedstock in liquid phase.