CN107653003B

CN107653003B - Method for preparing alkylate

Info

Publication number: CN107653003B
Application number: CN201610590283.9A
Authority: CN
Inventors: 胡合新; 李永祥; 付强; 张成喜; 慕旭宏
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2016-07-25
Filing date: 2016-07-25
Publication date: 2020-05-19
Anticipated expiration: 2036-07-25
Also published as: CN107653003A

Abstract

The invention relates to the field of petroleum processing, in particular to a method for preparing alkylate. The method for preparing the alkylate comprises the step of feeding a material containing isoparaffin and a material containing olefin into a reactor to contact with a solid acid catalyst, and is characterized in that the reactor sequentially comprises an alkylation reaction zone and a cracking reaction zone according to the material flow direction, the reaction temperature of the alkylation reaction zone is lower than the reaction temperature of the cracking reaction zone, and the liquid hourly space velocity of the cracking reaction zone is higher than the liquid hourly space velocity of the alkylation reaction zone. The method can prepare the alkylate with higher TMP/DMH ratio, higher octane number and less C9+ by-products, and can effectively improve the quality of the alkylate prepared by using the solid acid catalyst, wherein the octane number RON is more than 95. The method of the present invention can be applied to industrialization.

Description

Method for preparing alkylate

Technical Field

The invention relates to the field of petroleum processing, in particular to a method for preparing alkylate.

Background

The alkylation reaction of isoparaffin and olefin, which mainly refers to the alkylation reaction of isobutane and butene in industry, is a catalytic reaction process for converting isobutane into C8 branched paraffin (isooctane). The essence of this reaction is the organic addition reaction of alkane molecules with alkene molecules under the action of an acidic catalyst. Iso-C8 alkane (main component is trimethylpentane) generated by the reaction of isobutane and butene under the action of a strong acid catalyst is called alkylate. The alkylate oil is mainly saturated alkane, and basically has no olefin, aromatic hydrocarbon and sulfur, so that the pollution of automobile exhaust emission to air in the combustion process is greatly reduced. In addition, the alkylate oil also has the advantages of high octane number, low sensitivity, low steam pressure, high combustion heat value, no environmental pollution during combustion and the like, and is an ideal blend oil for aviation gasoline and motor gasoline. With the increasing deterioration of ecological environment and the increasing enhancement of environmental awareness, the alkylate oil becomes an ideal component of the gasoline with a new formula under the condition that the content of aromatic hydrocarbon, the content of olefin and the vapor pressure in the gasoline for automobiles are limited, and the production of the alkylate oil is more and more concerned.

The gasoline blending components in China mainly comprise catalytic gasoline, accounting for about 75%, and the high-performance alkylate components are seriously in short supply and are far lower than the alkylate content in developed countries (for example, the alkylate in the United states accounts for 13-15% of gasoline). The content of olefin and sulfur in the catalytic gasoline is relatively high, so that the catalytic gasoline is difficult to meet the strict regulation of a new environmental protection law, and the reformate is also restricted by the index of the content of benzene in the gasoline. Therefore, the development of an alkylation process and the improvement of the proportion of isoparaffin in the gasoline component are the most direct and effective ways for improving the quality of oil products in China.

Octane number is an important quality index of gasoline, and its value is closely related to the chemical composition of gasoline, with the lowest octane number of normal paraffins, the highest octane numbers of highly branched isoparaffins and aromatics, and the intermediate octane numbers of naphthenes. Isooctane (2,2, 4-trimethylpentane, hereinafter abbreviated as trimethylpentane) has an octane number of 100 and n-heptane of 0. In the isobutane/butene alkylation reaction, the reaction product comprises C5-C12 alkane and alkene, wherein the C8 product mainly comprises Trimethylpentane (TMP) and Dimethylhexane (DMH). The trimethyl pentane has high octane number and is a high-octane component which has important value on gasoline engine fuel; the octane number of the dimethyl hexane is lower and is only 55-75; the octane number of the products (C9+) of C9 and C9 is about 91, and the boiling point and the distillation range are relatively high, so that the gasoline cannot be completely evaporated and combusted, the gasoline consumption is increased, and the machine parts wear is increased. The higher the content of C8 in the alkylate oil is, the larger the TMP/DMH is, the fewer byproducts are, and the octane number of the alkylate oil is increased; in contrast, the alkylate is not homogeneous in composition, C₈The other light and heavy components are more, so the octane number is low, and other properties are also influenced.

Isobutane/butene alkylation is fast, often completing in several minutes, and in addition, side reactions such as cracking, folding, isomerization, disproportionation and polycondensation exist, generating numerous low-boiling (C5, C6, C7) products and high-boiling by-products (heavy components above C9 and C9). The alkylation reaction of isoparaffin and olefin is an exothermic reaction, the thermodynamic equilibrium of the reaction is facilitated at low temperature, the TMP content of high-octane components in the product is high, the TMP/DMH ratio is also high, and the product is very suitable for serving as an additive component of gasoline with high octane value. Lower reaction temperatures favor alkylation reactions, and thus, liquid acid alkylation is typically operated at lower temperatures. The reaction temperature of the alkylation of hydrofluoric acid is about 30 ℃ generally, and the reaction temperature of a sulfuric acid method is 8-12 ℃ generally; the reaction temperature of the CDALky low-temperature sulfuric acid process is even as low as 0 to-3 ℃, and the octane number of the produced gasoline is as high as more than 97.3.

The liquid acid alkylation process has a series of inevitable problems, such as large acid consumption, strong corrosivity, difficult waste acid treatment and the like. In order to avoid the harm to the environment and production operators, a solid acid alkylation process using a safe and reliable solid acid alkylation catalyst instead of a liquid acid is a necessary trend. Solid acid catalysts fall into four categories: metal halide catalysts, molecular sieve catalysts, super acid catalysts and heteropolyacid catalysts.

CN101717321A provides a process for solid acid catalyzed isobutane/n-butene alkylation. According to the method, Nafion functionalized hydrophobic SBA-15 is used as a catalyst, the reaction temperature is 100 ℃, the TMP/DMH ratio in the obtained reaction product is only 2, and the content of C9+ is more than 9%.

CN101570463A provides a method for alkylation of isoparaffin and olefin. In a magnetically stable fixed bed, the method uses magnetic solid acid to catalyze the reaction of butylene and isobutane, the reaction temperature is 10-250 ℃, the reaction pressure is 0.2-5.0MPa, and the weight space velocity is 1-30h^-1The ratio of alkane to alkene is 1-100, the magnetic field intensity is 1-1000e, and the catalyst and the product are easy to separate and convenient to regenerate. At the reaction temperature of 80 ℃, the content of C8 in the alkylate is 60-70%, the content of C9+ in the alkylate is 15-40%, and the TMP/DMH ratio and octane number are not given.

CN1362286A provides a catalyst for alkylation based on an inorganic or organic porous carrier and a heteropolyacid and a Lewis acid. The alkylate produced at supercritical temperature (136 deg.C) has C8 saturated hydrocarbon content of more than 75%, C9+ content of higher, about 15-20%, and TMP/DMH ratio of lower, only 3-4.

CN1238747A provides a catalyst of H-USY zeolite, at a reaction temperature of 90 ℃, the content of C5-C7 in the reaction product is 11%, C8 is 58%, C9+ is up to 30%, and TMP/DMH is 2.9. By optimizing the preparation process of the catalyst, the content of C8 is increased to 69 percent, TMP/DMH is 4.9, and the octane number is 94.1. The reaction temperature is still 90 ℃, the reaction temperature is higher, the reaction conditions are not continuously optimized, and the improvement of the content of high-octane product is not facilitated.

The existing solid acid alkylation reaction is generally carried out at a higher reaction temperature, which is unfavorable for thermodynamic equilibrium, so that the selectivity of a C8 alkylation product is poor, the TMP/DMH ratio is lower, a wider product distribution is obtained, and the octane number of the alkylate oil is easy to reduce; while the TMP/DMH ratio of the C8 product is high at the lower reaction temperature, the content of C9+ is obviously increased due to less cracking, so that the final boiling point of the alkylate is higher than 205 ℃, and the alkylate does not meet the national gasoline standard.

Disclosure of Invention

The invention aims to overcome the defects of low TMP/DMH ratio, low octane number and more C9+ byproducts commonly existing in the conventional method for carrying out alkylation reaction by using a solid acid catalyst, and provides a novel method for carrying out alkylation reaction by using a solid acid catalyst. The method of the present invention can be applied to industrialization.

The invention provides a method for preparing alkylate, which comprises the step of feeding a material containing isoparaffin and a material containing olefin into a reactor to contact with a solid acid catalyst, wherein the reactor sequentially comprises an alkylation reaction zone and a cracking reaction zone according to the material flow direction, the reaction temperature of the alkylation reaction zone is lower than the reaction temperature of the cracking reaction zone, and the liquid hourly space velocity of the cracking reaction zone is higher than the liquid hourly space velocity of the alkylation reaction zone.

The inventor of the invention finds that the existing solid acid catalytic alkylation reaction process cannot obtain the alkylate with better quality, and the foundation of the existing solid acid catalytic alkylation reaction process lies in that the content of C9+ in the alkylate is difficult to reduce, a higher content of C8 cannot be obtained, and the selectivity of C8 high-octane number components is poor, wherein the high-octane number TMP content is lower, the low-octane number DMH content is high, so that the TMP/DMH content is lower, and the gasoline octane number is lower. The inventor of the invention finds in the research process that the thinking set of the existing one-stage reaction is broken, the alkylation reaction zone and the cracking reaction zone are sequentially arranged according to the material flowing direction, the reaction temperature of the alkylation reaction zone is controlled to be lower than that of the cracking reaction zone, the hourly space velocity of the cracking reaction liquid is higher than that of the alkylation reaction zone, and the quality of the alkylate oil prepared by using the solid acid catalyst can be effectively improved.

The inventors of the present invention found that the principle that the method of the present invention can effectively improve the quality of alkylate produced using a solid acid catalyst may be that: the alkylation reaction zone mainly adopts a low-temperature alkylation reaction process, the TMP/DMH ratio in the product is high, but the cracking reaction is less, and the C9+ content is high; the cracking reaction zone has higher reaction temperature relative to the alkylation reaction, mainly uses the cracking reaction, and cracks heavy products C12 and C16 in C9+ into C5-C8. The content of C9+ is controlled below 12% by controlling two different temperatures. In addition, the two reaction zones carry out alkylation reaction and cracking reaction in sequence, and the alkylation reaction is taken as the main reaction zone, and the amount of catalyst filled in the alkylation reaction zone is greater than or far greater than that filled in the cracking reaction zone, so that the liquid hourly space velocity of the cracking zone is obviously greater than that of the alkylation zone.

According to a preferred embodiment of the present invention, when the reaction temperature of the alkylation reaction zone is 30-90 ℃ lower than the reaction temperature of the cracking reaction zone and the liquid hourly space velocity of the cracking reaction zone is 1-20 times higher than the liquid hourly space velocity of the alkylation reaction zone, the obtained alkylate may have a TMP/DMH ratio of at least 3, preferably at least 4 or more, more preferably at least 5, and an octane number RON of at least 94, preferably at least 95. The C9+ heavy components in the reaction product mainly comprise long-chain alkane and olefin with 12 and 16 carbon atoms and trace components with longer carbon chains, and the content of the C9+ components is high, so that the final distillation point of the alkylate oil is high, the boiling point and the distillation range are relatively high, the gasoline cannot be completely evaporated and combusted, the gasoline consumption is increased, and the machine part abrasion is increased. By the process of the present invention it is possible to achieve a C9+ content in the alkylate of less than 12%, preferably at least 10%. The solid acid alkylate oil produced by the method has high C8 content and high TMP/DMH ratio, can achieve the effect equivalent to or even better than that of liquid acid catalytic alkylation reaction, and is suitable for industrial production.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention provides a method for preparing alkylate, which comprises the step of feeding a material containing isoparaffin and a material containing olefin into a reactor to contact with a solid acid catalyst, and is characterized in that the reactor sequentially comprises an alkylation reaction zone and a cracking reaction zone according to the material flow direction, the reaction temperature of the alkylation reaction zone is lower than the reaction temperature of the cracking reaction zone, and the liquid hourly space velocity of the cracking reaction zone is higher than the liquid hourly space velocity of the alkylation reaction zone.

In the present invention, the manner of feeding the isoparaffin-containing material and the olefin-containing material into the reactor to contact with the solid acid catalyst is not particularly limited, and the organic liquid material may be reacted in the presence of the catalyst in a manner conventional in the art. The isoparaffin-containing material and the olefin-containing material can be one or more materials simultaneously containing isoparaffin and olefin, or one or more materials containing isoparaffin and one or more materials containing olefin, as long as the materials can be jointly contacted with the solid acid catalyst.

The inventor of the present invention finds that the quality of the obtained alkylate can be effectively improved by controlling the reaction temperature of the alkylation reaction zone to be lower than the reaction temperature of the cracking reaction zone and controlling the liquid hourly space velocity of the cracking reaction zone to be higher than the liquid hourly space velocity of the alkylation reaction zone. The alkylation and cracking reactions of the present invention are preferably carried out at relatively low reaction temperatures, for example, the reaction temperature in the alkylation reaction zone may be in the range of from 10 ℃ to 100 ℃, preferably from 30 ℃ to 70 ℃, more preferably from 30 ℃ to 50 ℃, and even more preferably from 30 ℃ to 40 ℃; the reaction temperature of the cracking reaction zone is 50-140 ℃, preferably 60-110 ℃, and further preferably 80-90 ℃; and the reaction temperature of the alkylation reaction zone is 30-90 deg.c lower, preferably 30-80 deg.c lower, more preferably 30-70 deg.c lower, even more preferably 40-60 deg.c lower than the reaction temperature of the cracking reaction zone.

In the present invention, the liquid hourly space velocity of the alkylation reaction zone may be in the range of from 30 to 150h^-1Preferably 30-100h^-1More preferably 30-70h^-1(ii) a The liquid hourly space velocity of the cracking reaction zone can be 50-3000h^-1Preferably 150-600h^-1More preferably 150 to 350 hours^-1(ii) a And the liquid hourly space velocity of the cracking reaction zone is 1 to 20 times, preferably 3 to 10 times, the liquid hourly space velocity of the alkylation reaction zone.

In the present invention, the pressure of the alkylation reaction zone and the cracking reaction zone is not particularly limited, and for example, the pressure of the alkylation reaction zone may be 1 to 5MPa, preferably 2 to 3 MPa; the pressure of the cracking reaction zone may be in the range of from 2 to 5MPa, preferably from 2 to 4 MPa. Unless otherwise stated, the pressure in the present invention is an absolute pressure.

The molar ratio of the isoparaffin to the olefin is as conventional in the art for alkylation reactions and may, for example, be from 100 to 1000: 1, preferably from 100 to 700: 1, more preferably 150 to 500: 1, more preferably 150 to 300: 1.

in the present invention, generally, the liquid hourly space velocity of the olefin may be in the range of from 0.01 to 0.5h^-1Preferably 0.03-0.4h^-1More preferably 0.05 to 0.2h^-1。

in the present invention, the solid acid catalyst used in the alkylation reaction zone and the cracking reaction zone may be a solid acid catalyst conventional in the art, for example, may be selected from one or more of metal halide catalyst, molecular sieve catalyst, super acid catalyst and heteropoly acid catalyst, preferably, the solid acid catalyst used in the process of the present invention is selected from one or more of Y-type molecular sieve, β -type molecular sieve, solid super acid, supported heteropoly acid and ZSM-5, more preferably, the solid acid catalyst used in the process of the present invention is selected from one or more of Y-type molecular sieve and β -type molecular sieve, wherein the Y-type molecular sieve is preferably H-Y-type molecular sieve and/or USY-type molecular sieve.

according to a preferred embodiment of the present invention, the solid acid catalyst used in the alkylation reaction zone is a relatively strong H-Y type molecular sieve, and the solid acid catalyst used in the cracking reaction zone is one or more of a relatively weak Y type molecular sieve other than the H-Y type molecular sieve and β type molecular sieve.

In the present invention, the alkylation reaction zone and the cracking reaction zone are not particularly limited, and may be arranged in this order in the direction of the material flow. The alkylation reaction zone and the cracking reaction zone can be two zones in the same reactor, and can also be respectively a reactor or a plurality of reactors. When the alkylation reaction zone and the cracking reaction zone are two zones in the same reactor, the liquid hourly space velocity is controlled by controlling the filling amount of the catalyst, and the filling amount of the alkylation reaction catalyst is generally 1-20 times, preferably 3-10 times of the cracking reaction mainly based on the alkylation reaction. The temperature of the alkylation reaction zone and the cracking reaction zone is controlled by respectively arranging external heating devices. When the alkylation reaction zone and the cracking reaction zone are respectively a plurality of reactors, the series of reactors used as the alkylation reaction zone and the series of reactors used as the cracking reaction zone are connected in series, the series of reactors used as the alkylation reaction zone are connected in parallel or in series, and the series of reactors used as the cracking reaction zone are connected in parallel or in series. The material may flow in either upward or downward direction. The reaction material can be fed from the top layer or the bottom layer of the catalyst or can be fed from different catalyst beds in a segmented mode.

In the present invention, the reactor of the alkylation reaction zone and the reactor of the cracking reaction zone may be the same or different, and may be independently selected from one or more of a fixed bed reactor, a batch tank reactor, a moving bed reactor and a fluidized bed reactor, preferably a fixed bed reactor. In the case of a fixed bed reactor, the fixed bed reactor may be packed in a manner conventional in the art, for example, by packing quartz sand of 30 to 50 mesh in each of 1/10 to 1/5 of the bottom and the top, respectively, and packing a solid acid catalyst in the middle. The particle size of the solid acid catalyst is not particularly limited, and may be, for example, 20 to 40 mesh.

In the present invention, it is preferred to carry out a pretreatment before each alkylation reaction and before each cracking reaction, and the pretreatment may be carried out by a pretreatment process conventional in the art, and may include, for example: the reactor is purged with an inert gas such as nitrogen, the catalyst is dried at 200-350 c, preferably 250 c, for 8-12h, preferably 10h, and then cooled to the reaction temperature.

In the present invention, the kind of isoparaffin and olefin to be reacted is not particularly limited, and the selection of a specific kind does not affect the performance of the method of the present invention, and may be selected in a manner conventional in the art. For example, the isoparaffin may be one or more of isoparaffins from C4 to C6, more preferably one or more of isoparaffins from C4 to C5, such as isobutane, isopentane, or a mixture thereof, most preferably isobutane. The olefin can be C2 or above monoene, preferably one or more of C2-C6 monoene, such as one or more of propylene, butene and pentene, more preferably one or more of butene-1, butene-2 and isobutene.

According to the invention, through two-stage reaction of alkylation reaction at a lower temperature and a lower liquid hourly space velocity and then cracking reaction at a higher temperature and a higher liquid hourly space velocity, the content of C5-C7 and C9+ in the obtained alkylate oil can be lower, the content of C8 is higher, especially the content of TMP is higher, so that TMP/DMH is higher and the octane number is higher. The quality of the alkylate oil obtained by the method is higher and can be equal to or better than that of the alkylate oil obtained by a liquid acid method, so that industrialization can be realized.

The present invention will be described in detail below by way of examples. In the following examples and comparative examples, each reaction was preceded by a pretreatment comprising: the reactor was purged with nitrogen, the catalyst was dried at 250 ℃ for 10h and then cooled to reaction temperature. The pretreatment process is not described in detail in the following examples and comparative examples.

In the following examples and comparative examples, the weight distributions of C5-C7, C8 and C9+ and TMP/DMH of the obtained alkylates were determined by anglient-7890 gas chromatography (HP-PONA 50 m.times.0.2 mm capillary column) equipped with a high pressure sampler. The octane value RON of the obtained alkylate is measured and calculated by gas chromatography, and the specific method comprises the following steps: firstly, determining the volume percentages of various hydrocarbons in a product by a chromatograph, then multiplying the volume percentages by the RON value of the single-component hydrocarbon, and adding to obtain the octane number of the alkylate oil; this calculation method is the same as that of CN 1238747A. The gasoline distillation range determination method is carried out according to the method specified in GB/T6536-1997 standard.

Example 1

Two serially connected diameters of

The filling mode and the reaction conditions of the two fixed bed reactors are as follows:

in the first fixed bed reactor, 40-mesh quartz sand was charged at 1/6 of the bottom and top, and 20-40-mesh 10 g of H-Y molecular sieve type catalyst (from China petrochemical catalyst Co., Ltd.) was charged at the middle constant temperature section. The reaction conditions include: the reaction temperature is 30 ℃, the reaction pressure is 3MPa, and the liquid hourly space velocity is 50h^-1。

in the second fixed bed reactor, 40 mesh quartz sand is filled at the bottom and 1/6 of the top, 20-40 mesh 3 g H- β molecular sieve type catalyst (purchased from China petrochemical catalyst Co., Ltd.) is filled in the middle constant temperature section, the reaction conditions include that the reaction temperature is 90 ℃, the pressure in the reactor is controlled to be about 3.0MPa through a back pressure valve at the outlet of the reactor, and the liquid hourly space velocity is 166H^-1。

And (2) enabling a mixed material containing isoparaffin and olefin (comprising isobutane and butene, wherein the molar ratio of the isobutane to the butene is 200: 1) to sequentially pass through the first fixed bed reactor and the second fixed bed reactor, and collecting alkylate oil obtained by reaction from an outlet of the second fixed bed reactor, wherein the alkylate oil is marked as I1.

Comparative example 1

The procedure is as in example 1, except that the filling pattern, pretreatment process and reaction conditions of the second fixed bed reactor are set to be identical to those of the first fixed bed reactor, and the reaction temperatures of both fixed bed reactors are 30 ℃. The alkylate obtained in the reaction was collected at the outlet of the second fixed bed reactor and was designated as D1.

Comparative example 2

The procedure was as in example 1, except that the filling pattern, pretreatment process and reaction conditions of the second fixed bed reactor were set to be exactly the same as those of the first fixed bed reactor, and the reaction temperatures of both fixed bed reactors were set to 70 ℃. The alkylate obtained in the reaction was collected at the outlet of the second fixed bed reactor and was designated as D2.

Comparative example 3

The procedure was as in example 1, except that the filling pattern, pretreatment process and reaction conditions of the second fixed bed reactor were all set to be identical to those of the first fixed bed reactor, and the reaction temperatures of both fixed bed reactors were set to 90 ℃. The alkylate obtained in the reaction was collected at the outlet of the second fixed bed reactor and was designated as D3.

Comparative example 4

The procedure was followed as in example 1, except that the filling pattern, pretreatment process and reaction conditions of the second fixed bed reactor were all set to be identical to those of the first fixed bed reactor, and the reaction temperatures of both fixed bed reactors were set to 110 ℃. The alkylate obtained in the reaction was collected at the outlet of the second fixed bed reactor and was designated as D4.

The product distributions and TMP/DMH values of the alkylates D1-D4 obtained in example 1 and comparative examples 1-4, respectively, were determined and the results are reported in Table 1. The distillation range and octane number of the alkylates D1-D4 obtained in example 1 and comparative examples 1-4 were determined, respectively, and the results are reported in Table 2.

TABLE 1

TABLE 2

It can be seen from example 1 that, when the alkylation reaction is carried out at a low temperature of 30 ℃ and the cracking reaction is carried out at a temperature of 90 ℃ by adopting the method disclosed by the invention, the content of C9+ in the obtained reaction product is lower than 10%, the final boiling point is 189.8 ℃, the distillation range of the obtained alkylate oil is completely qualified, and the requirements on the distillation range in the national standard GB17930-2011 (the final boiling point is lower than 205 ℃, the 10% evaporation temperature is lower than 70 ℃, the 50% evaporation temperature is lower than 120 ℃, and the 90% evaporation temperature is lower than 190 ℃) are met, meanwhile, the TMP/DMH ratio reaches 5.7, and the octane number RON reaches 95.5, which are both higher levels.

Comparing example 1 with comparative examples 1-4, it can be seen that when the conditions of the two reactors are the same (equivalent to a one-stage reaction in the prior art), when the reaction is carried out at 30 ℃ which is lower in temperature (comparative example 1), the distillation range of the alkylate oil is higher due to the high content of C9+ heavy components in the reaction product because of the low reaction temperature, so that the distillation range reaches 209.7; however, when the reaction is carried out at low temperature, the high-octane component TMP is high in content, and the low-octane component DMH is low in content, so that the TMP/DMH ratio is high, and the alkylate oil octane number is high. At higher temperatures of 110C (comparative example 4), the cracking reaction was enhanced to minimize C9+ components in the product and lower alkylate boiling range, but the high octane components were lower in TMP content and TMP/DMH ratio, resulting in lower alkylate octane. It can be seen that in the one-stage reaction, the optimized reaction temperature is 70 ℃ (comparative example 2), and the alkylate oil obtained by the method has better quality and higher octane number and TMP/DMH ratio compared with other comparative examples. Example 1 by optimizing comparative example 2, the quality of the obtained alkylate is improved compared with that of comparative example 2, and the TMP/DMH ratio and the octane number are both obviously improved.

Example 2

The procedure is as in example 1, except that the first fixed bed reactor and the second fixed bed reactor are at 40 ℃ and 80 ℃ respectively, a mixed feed comprising isoparaffin and olefin (wherein the molar ratio of isobutane to butene is 200: 1) is passed through the first fixed bed reactor and the second fixed bed reactor in sequence, and the alkylate obtained by the reaction is collected from the outlet of the second fixed bed reactor and is designated as I2.

Example 3

The procedure was carried out as in example 1, except that the solid acid catalysts loaded in the first fixed bed reactor and the second fixed bed reactor were the same, and were each the H-Y molecular sieve type catalysts of example 1, 10.0g and 2.0g, respectively, and the liquid hourly space velocity was 60H^-1、300h^-1. The alkylation obtained by the reaction is collected from the outlet of the second fixed bed reactorOil, as I3.

Example 4

Two fluidized bed reactors connected in series are arranged and named as a first fluidized bed reactor and a second fluidized bed reactor in sequence according to the material flow direction, wherein the first fluidized bed reactor is the same as the catalyst filled in the first fixed bed reactor in the example 1 and has the same reaction conditions, and the second fluidized bed reactor is the same as the catalyst filled in the second fixed bed reactor in the example 1 and has the same reaction conditions. The alkylate obtained in the reaction was collected from the outlet of the second fluidized bed reactor and was designated as I4.

The product distributions and TMP/DMH values of the alkylates I2-I4 obtained in examples 2-4 were determined, respectively, and the results are shown in Table 3. The boiling range and octane number of the alkylates I2 to I4 obtained in examples 2 to 4 were measured, respectively, and the results are shown in Table 4.

TABLE 3

TABLE 4

It can be seen from the combination of tables 3 and 4 that the distillation range of the alkylate oil prepared according to the example of the method of the present invention meets the requirements of national standard GB17930-2011, and the TMP/DMH ratio and the octane number are higher, which are better than the reaction result at 70 ℃ under the optimal condition of the first-stage reaction formula (comparative example 2). The method can obviously improve the content of the C8 component, reduce the content of C9+ heavy components, improve the selectivity of trimethylpentane and the ratio of trimethylpentane/dimethylhexane, and effectively improve the quality of alkylate oil.

It can be seen from examples 2-4 that better quality alkylate can still be obtained when the alkylation reaction temperature and the cracking reaction temperature are varied and a fluidized bed reactor is used.

The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention. It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition. In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims

1. A method for preparing alkylate, said method comprises feeding the supplies comprising isoparaffin and containing olefin into the reactor to contact with solid acid catalyst, characterized by, according to the direction that supplies flow, said reactor includes alkylation reaction zone and cracking reaction zone sequentially, the reaction temperature of said alkylation reaction zone is lower than the reaction temperature of said cracking reaction zone, and the liquid hourly space velocity of the said cracking reaction zone is higher than the liquid hourly space velocity of the said alkylation reaction zone; the reaction temperature of the alkylation reaction zone is 10-100 ℃, the reaction temperature of the cracking reaction zone is 50-140 ℃, and the reaction temperature of the alkylation reaction zone is 30-90 ℃ lower than that of the cracking reaction zone;

the olefin-containing material is one or more of C2-C6 monoenes;

in the alkylate, the ratio of TMP/DMH is at least 3, the octane number RON is more than 95, and the content of C9+ components is less than 12 wt%.

2. The process of claim 1 wherein the reaction temperature of the alkylation reaction zone is 30-70 ℃, the reaction temperature of the cracking reaction zone is 60-110 ℃, and the reaction temperature of the alkylation reaction zone is 30-80 ℃ lower than the reaction temperature of the cracking reaction zone.

3. The method of claim 1 or 2The method, wherein the liquid hourly space velocity of the alkylation reaction zone is 30-150h^-1The liquid hourly space velocity of the cracking reaction zone is 50-3000h^-1And the liquid hourly space velocity of the cracking reaction zone is 1-20 times the liquid hourly space velocity of the alkylation reaction zone.

4. The process of claim 3 wherein the liquid hourly space velocity of the alkylation reaction zone is in the range of from 30 to 100h^-1The liquid hourly space velocity of the cracking reaction zone is 150-600h^-1And the liquid hourly space velocity of the cracking reaction zone is 3-10 times of the liquid hourly space velocity of the alkylation reaction zone.

5. The process of claim 1 wherein the pressure in the alkylation reaction zone is from 1 to 5MPa, the pressure in the cracking reaction zone is from 2 to 5MPa, and the molar ratio of isoparaffin to olefin is from 100 to 1000: 1.

6. the process of claim 5 wherein the pressure in the alkylation reaction zone is from 2 to 3MPa, the pressure in the cracking reaction zone is from 2 to 4MPa, and the molar ratio of isoparaffin to olefin is from 100 to 700: 1.

7. the process of claim 1 wherein the solid acid catalyst used in the alkylation reaction zone and the cracking reaction zone is the same or different.

8. The process of claim 7 wherein the solid acid catalyst used in the alkylation reaction zone is more acidic than the solid acid catalyst used in the cracking reaction zone.

9. the process of any one of claims 1, 7 and 8, wherein the solid acid catalyst is selected from one or more of Y-type molecular sieves, β -type molecular sieves, solid superacids, supported heteropolyacids and ZSM-5.

10. the process of claim 9, wherein the solid acid catalyst is selected from one or more of Y-type molecular sieves and β -type molecular sieves.

11. The process of claim 10, wherein the Y-type molecular sieve is an H-Y-type molecular sieve and/or a USY-type molecular sieve.

12. The process of claim 1 wherein the alkylation reaction zone and the cracking reaction zone are two zones in the same reactor or are each one or more reactors.

13. The method of claim 12, wherein the reactor is selected from one or more of a fixed bed reactor, a batch tank reactor, a moving bed reactor, and a fluidized bed reactor.

14. The method of claim 13, wherein the reactor is a fixed bed reactor.