CN109988637B

CN109988637B - Flexible paraffin hydrogenation process

Info

Publication number: CN109988637B
Application number: CN201711468905.1A
Authority: CN
Inventors: 刘涛; 李宝忠; 张忠清; 张艳侠; 马蕊英; 姚春雷
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: 2021-05-04
Anticipated expiration: 2037-12-29
Also published as: CN109988637A

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 passes through a gas-liquid separator arranged in the middle of a bed layer, is separated to obtain liquid, is pumped out of a refining reactor and is mixed with hydrogen, and then enters a hydroisomerization reactor to carry out isomerization reaction; the other material is a mixture of gas in the reactor and liquid left after extraction, and the mixture 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 liquid material flow is extracted from a gas-liquid separator arranged in the middle of a hydrofining reactor, and the paraffin raw material is flexibly produced into high-quality hydrofined paraffin products and hydroisomerized paraffin products by a hydrofining and hydroisomerizing combined method.

The flexible paraffin hydrogenation process comprises the following steps:

a. passing the paraffin raw material through a hydrofining catalyst bed layer on the upper part of a hydrofining reactor under the hydrofining condition to obtain a first hydrofining material flow; the part of the reaction material flow is divided into two parts, wherein one part of the reaction material flow passes through a gas-liquid separator, and liquid material flow obtained by separation is pumped 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 hydrofining liquid 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 hydro-upgrading high-pressure hydrogen-rich gas obtained in the step (b) with the hydro-isomerism 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 a gas-liquid separator arranged in the middle of a bed layer of a hydrofining reactor, a part of hydrofining material flow is separated, and liquid materials are extracted, so that the effective distribution of hydrofining material flows can be realized; and then the obtained material is subjected to different hydrogenation processes, so that the paraffin wax 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 gas-liquid separator is arranged in the middle of the catalyst bed layer of the hydrofining reactor, the first hydrofining liquid flow obtained by hydrofining the paraffin raw material is extracted out of the reactor through the gas-liquid separator and sent into the independently arranged hydroisomerization reactor for 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 impurities such as S, N in the raw oil are converted into H after hydrofining and partial hydro-upgrading₂S and NH₃Most of H is separated by a gas-liquid separator₂S and NH₃Present in the gas phase, and H in the liquid phase₂S and NH₃The content of (A) is less, so that the inhibiting effect on the molecular sieve of the hydroisomerization catalyst is reduced, the reaction activity of the hydroisomerization catalyst is improved, namely the reaction temperature required for achieving the same isomerization effect is reduced, the liquid obtained in the middle of a refining catalyst bed layer of a hydrofining reactor has very high temperature and pressure, and the temperature after the liquid is mixed with the circulating hydrogen is slightly althoughThe reaction can be carried out in a newly arranged hydroisomerization reactor, and the pour point depression effect is achieved, so that the heat carried by the part of refined material is fully utilized, and the coupling operation of the hydrofining reactor and the hydroisomerization reactor is realized.

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, 19-hydroisomerized reactor recycle hydrogen, 20-gas-liquid separator.

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 is alumina, amorphous silica-alumina, silica, titania, etc. and may contain other assistant, such as P, Si, B, Ti, Zr, etc. The catalyst may be used commercially or may be prepared by methods known in the art. The hydrogenation active component is a catalyst in an oxidation state, and is subjected to conventional vulcanization treatment before use, so that the hydrogenation active component is converted into a vulcanization 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 hydrorefining conditions may be conventional onesThe reaction conditions are that 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.

In the step a, the gas-liquid separator is a device arranged between the beds of the hydrofining reactor or at the inlet of the catalyst bed. The gas-liquid separator at least comprises a reactant stream inlet, a liquid phase conduit, a gas phase conduit and the like, wherein the liquid phase conduit extracts a separated liquid phase out of the hydrofining reactor, and the gas phase conduit introduces a separated gas phase into a lower hydrofining catalyst bed layer.

And b, allowing a part of hydrofining reactant flow in the step a to enter a gas-liquid separator through an inlet of the gas-liquid separator, wherein the extracted liquid flow accounts for 5-95 wt% of the raw oil, 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 is one or more of alumina, silicon-containing alumina and molecular sieve, preferably molecular sieve, and the molecular sieve can be beta type molecular sieve, Sapo type molecular sieve, etc. 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 is10wt% -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^-1~12.0h^-1The average reaction temperature is 150-400 ℃, 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 150-400 ℃, 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: firstly, paraffin raw material 1 is mixed with recycle hydrogen 2 and enters a hydrofining reactor 3, a reaction material flow passing through a first hydrofining catalyst bed layer is subjected to gas-liquid separation by a gas-liquid separator 20 to extract a hydroisomerized liquid raw material flow 4, the material flow after the hydroisomerized raw material flow 4 is extracted continues to enter a subsequent hydrofining catalyst bed layer, a hydrofining generated material flow 5 enters a hydrofining high-pressure separator 6 for gas-liquid separation, the separated liquid enters a fractionating tower 10 for fractionation to obtain a hydrofined naphtha product 12 and a hydrofined paraffin product 14, the hydroisomerized liquid raw material flow 4 is mixed with hydroisomerized recycle hydrogen 19 and then enters a hydroisomerizing reactor 7, a product flow 8 passing through the hydroisomerizing catalyst bed layer enters a hydroisomerizing high-pressure separator 9 for gas-liquid separation, the separated liquid enters a fractionating tower 11 for fractionation to obtain a hydroisomerized naphtha product 14 and a hydroisomerized, the hydrofined naphtha product 12 and the hydroisomerization naphtha product 14 can be used as separate products or can be mixed to obtain a mixed naphtha product, and the gas 16 obtained by separating the hydrofined high-pressure separator 6 and the gas 17 obtained by separating the hydroisomerization high-pressure separator 9 are mixed and then are mixed with make-up hydrogen 18 to be used as recycle hydrogen after passing through a recycle hydrogen compressor.

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

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

Claims

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

a. passing the paraffin raw oil 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; the part of the reaction material flow is divided into two parts, wherein one part of the reaction material flow passes through a gas-liquid separator, and liquid material flow obtained by separation is pumped out of the hydrofining reactor;

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 according to claim 1, wherein the raw paraffin oil is at least one selected from the group consisting of liquid paraffin, high-melting petroleum wax, microcrystalline wax, mixed microcrystalline wax and 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 liquid stream extracted in step a accounts for 5-95 wt% of the raw oil.

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 catalyst.

9. The hydrogenation process of claim 7, 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. The hydrogenation process according to claim 6, wherein the mass ratio of the liquid stream extracted in step a to the raw oil is 10-80 wt%.