A method for mixing light hydrocarbon de-olefination and its application

Abstract

The application provides a method for removing olefins from mixed light hydrocarbons and application thereof, and the method comprises the following steps: under the action of a catalyst, olefins in the mixed light hydrocarbons are converted to mainly generate higher heavy components, and the light hydrocarbons remaining in the reaction are mainly alkane components; wherein the catalyst is a binder-free molecular sieve catalyst. The application mainly solves the problem that the existing mixed light hydrocarbons cannot be directly used as the raw material of an ethylene cracking device due to containing a certain concentration of olefins. The application adopts the technical scheme that the olefins in the mixed light hydrocarbons are basically converted in the presence of the binder-free molecular sieve catalyst to mainly generate higher carbon five and above heavier components, and the remaining light hydrocarbons are basically alkane components, the olefin components in the mixed light hydrocarbons are removed in one step, and the problem is better solved, and the method can be used in industrial production.

Description

Technical Field

[0001] This invention relates to a method for deolefination of mixed light hydrocarbons and its application. Background Technology

[0002] With the growth of my country's national economy, the demand for basic organic chemical raw materials such as ethylene and propylene has increased significantly. The supply of naphtha, the raw material used in these products, is relatively tight and its price fluctuates greatly due to the fluctuations in oil reserves and the market. Therefore, petrochemical companies are vying to "make the most of" crude oil resources to maximize their value.

[0003] C4 is a byproduct of the petrochemical and refining industries. With the improvement of my country's crude oil processing capacity, its output is huge, and it is usually used as a domestic fuel gas with relatively low value. On the other hand, with the successful implementation of my country's Western Development Strategy and the West-East Gas Pipeline Project, C4 will become even more abundant.

[0004] Therefore, how to utilize C4 resources to generate greater value is an important issue. There are many methods for the resource utilization of C4 olefins, such as isobutene to produce butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and olefin alkylation products, which are used extensively as gasoline blending additives; separation and refining to produce polymer-grade n-butene; and other new technologies such as olefin catalytic cracking to produce propylene and ethylene, and butene-2 ​​and ethylene to produce propylene. These provide good solutions for the deep processing of C4 olefins and the production of high value-added products.

[0005] However, most mixed C4 compounds, such as those produced as refinery byproducts, are currently mainly used as liquefied petroleum gas (LPG) fuel for civilian applications due to their low olefin concentration and high energy consumption for chemical utilization. But the butane in mixed C4 compounds can undergo high-temperature steam cracking to produce ethylene and other products. Therefore, how to use these C4 compounds as feedstocks for high-temperature cracking to produce ethylene and propylene, thereby maximizing their value, is a significant research topic. Typically, because mixed C4 compounds contain a certain concentration of olefins, they undergo severe coking at high temperatures, making them unsuitable for direct use as feedstock for ethylene cracking.

[0006] To solve this technical problem, existing technologies typically employ a process of full hydrogenation of the feedstock to remove olefins, reducing the olefin content of the cracking feedstock to a level permissible by production technology. However, this method requires a large amount of precious hydrogen resources.

[0007] Existing technologies for reducing mixed C4 olefins include:

[0008] CN1827564A discloses a method for producing diesel fuel from C4 components containing butene by cascading. This technology uses a C4 butene cascading reaction, and then separates the gasoline fraction and diesel fraction from the liquid product of the cascading reaction. The olefins in the gasoline fraction are then subjected to a cascading reaction to increase the yield of diesel fuel in the cascading product. However, its butene conversion rate is low, only about 80%.

[0009] CN111217662A discloses a method for preparing isooctane by isobutylene condensation. This method uses a macroporous strong acid cation exchange resin with hydrogenation activity to carry out a condensation-hydrogenation reaction between hydrogen and raw materials containing isobutylene in a reactor to generate isooctane. Although the process is simple and only utilizes isobutylene, the overall butene conversion rate is low.

[0010] CN110129088A discloses a method for producing ethylene cracking feedstock through mixed hydrogenation of low-carbon hydrocarbons. The method uses a mixture of coking naphtha, coking liquefied petroleum gas (LPG), and post-etherified C4 as feedstock gas. A two-stage full hydrogenation technology is employed, controlling the heat release of the reaction to ensure catalyst and reaction performance. The reaction products undergo complex separation to obtain refined naphtha. This technology requires a large amount of expensive hydrogen resources.

[0011] CN107286983B discloses a method for producing gasoline components from C4 olefin oligomerization, using ZSM-35 molecular sieve as a catalyst. The aim is to convert a large amount of butene in C4 olefins into gasoline components, achieving a relatively high gasoline yield. According to its specification, this technology is mainly for C4 olefins with a high concentration of olefins (butene concentration around 90%), and its highest single-pass butene conversion rate is 88%, which has not yet reached the level of basic conversion.

[0012] CN1597867A discloses a catalyst for the olefin aromatization and alkylation reactions in refinery liquefied petroleum gas to produce high-octane clean gasoline components. This catalyst is made by mixing one or more of ZSM-5, ZSM-11, MCM-22, and ZSM-35 molecular sieves with a SiO2 / Al2O3 molar ratio of 20–80 with an inert component to form a hydrogen-type molecular sieve, followed by the introduction of rare earth elements. The molecular sieve content is 15–70 wt%, the rare earth element content is 0–5 wt%, and the remainder is a binder. Under conditions of 250–450°C, the resulting gasoline component has a high aromatic content and a high octane number. However, this invention involves the simultaneous olefin conversion and the participation of some alkanes in the aromatization reaction, consuming alkane feedstock.

[0013] CN103102235B discloses a catalyst for the isomerization of n-butene to produce isobutene and concurrently high-octane gasoline components. HZSM-35 is used as the catalyst, and post-etherified mixed C4 is used as the feedstock. The process is organically combined with dual-temperature control and carbon deposition on the catalyst surface. The first stage reaction temperature is 200–300℃, and the second stage reaction temperature is 300–350℃, carried out at atmospheric pressure for 0.5–1 hour. -1 Under these conditions, the highest yield of high-octane gasoline components was 24.89%. The conversion rate of C4 olefins using this method was only around 50%. Summary of the Invention

[0014] One of the technical problems to be solved by this invention is to address the low conversion rate of C4 olefins in the prior art. It provides a relatively simple method that can remove olefins from mixed light hydrocarbons in one step, so that the remaining C4 components are basically alkanes that can be directly used as feedstock for ethylene cracking, while avoiding the use of scarce resources such as hydrogen. At the same time, gasoline components are also produced as byproducts. This method has the characteristics of high alkane yield and complete conversion of C4 olefins.

[0015] According to the present invention, a method for deolefination of mixed light hydrocarbons is provided. The method includes: reacting and converting the olefins in the mixed light hydrocarbons under the action of a catalyst to mainly generate higher-grade heavy components, and the remaining light hydrocarbons are mainly alkane components; wherein the catalyst is a binder-free molecular sieve catalyst.

[0016] This invention provides the application of the method described herein in ethylene cracking.

[0017] This invention primarily addresses the problem that existing mixed light hydrocarbons, containing a certain concentration of olefins, cannot be directly used as feedstock for ethylene cracking units. The invention employs a technique in the presence of a binder-free molecular sieve catalyst to fundamentally convert the olefins in the mixed light hydrocarbons, mainly producing higher-grade C5 and above heavier components. The remaining light hydrocarbons are primarily alkane components. This one-step reaction essentially removes the olefin components from the mixed light hydrocarbons, effectively solving the problem and making it suitable for industrial production.

[0018] This invention can use a mixture of light hydrocarbons with an appropriate olefin concentration of 5-60%, for example, about 30%, as raw materials. The reaction can be carried out in a small-scale reaction device. The reaction tail gas is directly introduced into an online gas chromatograph to sample and analyze the reaction products online, calculate the reaction performance, and compare the technical effects of the technical solution of this invention.

[0019] Through the technical solution of this invention, it was found that the highest olefin conversion rate of mixed light hydrocarbons reached over 96%, and the olefin reduction effect of this invention was significant, with the olefin concentration in the remaining light hydrocarbons being less than 2%. At the same time, it was unexpectedly found that alkanes also accounted for the majority of the C5 and C6 components generated in the reaction.

[0020] According to the method of the present invention, components with different numbers of carbon atoms, such as C4, C5, C6 and above, can be conveniently separated by conventional distillation methods as needed, thereby obtaining products with an olefin content of less than 2%, thus obtaining raw materials that can fully meet the requirements of steam cracking production.

[0021] The technical solution of this invention also yields good results when performing deolefination of light hydrocarbons with C5 or higher carbon content. Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] This invention provides a method for removing olefins from mixed light hydrocarbons. The method includes: reacting and converting the olefins in the mixed light hydrocarbons under the action of a catalyst, mainly generating higher-grade heavier components, with the remaining light hydrocarbons being primarily alkane components; wherein the catalyst is a binder-free molecular sieve catalyst. This invention, by employing a binder-free molecular sieve catalyst to react and convert the olefins in mixed light hydrocarbons, mainly generating higher-grade C5 and above heavier components, with the remaining light hydrocarbons being primarily alkane components, effectively removes the olefin components from the mixed light hydrocarbons in a one-step reaction, thus solving the problem effectively. This method can be used in industrial production and effectively addresses the issue that existing mixed light hydrocarbons containing a certain concentration of olefins cannot be directly used as feedstock for ethylene cracking units.

[0024] In this invention, "higher weight components" refers to heavier components with C5 or higher carbon content.

[0025] According to a preferred embodiment of the present invention, preferably, the content of alkane components in the remaining light hydrocarbons after the reaction is 95% by weight or more, preferably 97% by weight or more, and more preferably 99% by weight or more. This allows for the convenient acquisition of butane with an olefin content as low as 2% or less using conventional distillation methods.

[0026] According to a preferred embodiment of the present invention, preferably, the content of heavier components with C5 or more carbon atoms in the product of the reaction conversion is 5% by weight or more, preferably 5-30% by weight. Thus, the product can be directly used as feedstock for an ethylene cracking unit.

[0027] According to a preferred embodiment of the present invention, preferably, the mixed light hydrocarbons are a mixture of C4 and / or C5 hydrocarbons.

[0028] In this invention, the binder-free molecular sieve catalyst refers to a molecular sieve that, after being formed with a binder, undergoes solid-state crystallization treatment of the binder, essentially transforming the binder into the corresponding molecular sieve, resulting in a binder content of less than 5%.

[0029] According to a preferred embodiment of the present invention, preferably, the binder-free molecular sieve catalyst refers to a shaped catalyst containing molecular sieves and binders in which the binder is crystallized and converted into the corresponding molecular sieve, and the binder content is less than 5% by weight.

[0030] According to a preferred embodiment of the present invention, the method for preparing the binder-free molecular sieve catalyst preferably includes:

[0031] a) Under alkaline conditions, molecular sieve powder, binder, and optional extrusion aid are shaped, dried, and calcined to obtain a catalyst preform of the desired shape.

[0032] b) The catalyst preform is placed in a vapor containing an organic amine solution and subjected to solid-state crystallization treatment at 100-200°C, preferably 120-140°C, for 24-240 hours, preferably 100-150 hours.

[0033] c) The crystallized embryo is subjected to ammonium exchange and calcination to obtain a hydrogen-form molecular sieve catalyst;

[0034] According to a preferred embodiment of the present invention, preferably, step a) is carried out in the presence of an alkali metal hydroxide, more preferably in the presence of sodium hydroxide.

[0035] According to a preferred embodiment of the present invention, preferably, preferably, in step b), the organic amine is triethylamine.

[0036] According to a preferred embodiment of the present invention, preferably, the concentration of the organic amine-containing solution is 20-40% by weight.

[0037] According to a preferred embodiment of the present invention, the method for preparing the binder-free molecular sieve catalyst preferably includes:

[0038] a) In the presence of alkali metal hydroxides, molecular sieve powder, binder and extrusion aid are shaped, dried and calcined to obtain catalyst preforms of the desired shape;

[0039] b) The catalyst preform is placed in a vapor containing triethylamine solution and subjected to solid-state crystallization treatment at 100-200°C, preferably 120-140°C, for 24-240 hours, preferably 100-150 hours.

[0040] c) The crystallized embryo is subjected to ammonium exchange and calcination to obtain a hydrogen-type molecular sieve catalyst.

[0041] According to a preferred embodiment of the present invention, a more preferred method for preparing the binder-free molecular sieve catalyst includes:

[0042] a) An alkali metal hydroxide is mixed with a binder to obtain an alkali metal sol, and then molecular sieve powder and extrusion aid are added to mix and extrude, dry and calcined to obtain a catalyst preform of the required shape.

[0043] b) The catalyst preform is placed in a vapor containing triethylamine solution and subjected to solid-state crystallization treatment at 100-200°C for 24-240 hours, preferably 100-150 hours.

[0044] c) The crystallized embryo is subjected to ammonium exchange and calcination to obtain a hydrogen-type molecular sieve catalyst.

[0045] The dosage of each substance in this invention has a wide range of options. According to a preferred embodiment of this invention, the weight ratio of alkali metal hydroxide, binder (calculated as oxide), molecular sieve powder and extrusion aid is preferably 1-3:30-50:100:1-5.

[0046] According to a preferred embodiment of the present invention, the weight ratio of triethylamine solution to catalyst preform is preferably 3-5:1.

[0047] According to a preferred embodiment of the present invention, the molecular sieve is at least one of mordenite, MCM-22, MCM-23, MCM-49, MCM-56, ZSM-5, ZSM-11, ZSM-23, ZSM-35, β, and Y, preferably ZSM-5 and / or ZSM-11. In the embodiments of the present invention, ZSM-5 is used as an example.

[0048] According to a preferred embodiment of the present invention, the SiO2 / Al2O3 molar ratio of the molecular sieve is preferably in the range of 30 to 300, more preferably 30 to 200, and even more preferably 30 to 60.

[0049] According to the present invention, the range of types of adhesives that can be selected is relatively wide, and commonly used adhesives can be used in the present invention. For the present invention, the adhesive is preferably silica sol, and the solid content of the silica sol is preferably 30-50% by weight.

[0050] According to the present invention, the range of types of extrusion aids is relatively wide, and commonly used extrusion aids can be used in the present invention. For the present invention, the extrusion aid is preferably guar gum powder.

[0051] According to a preferred embodiment of the present invention, the reaction conversion conditions include: a reaction temperature of 250–450°C, preferably 280–400°C.

[0052] According to a preferred embodiment of the present invention, the reaction conversion conditions include: a reaction pressure of 0.05 to 2.0 MPa, preferably 0.1 to 1.5 MPa.

[0053] According to a preferred embodiment of the present invention, the reaction conversion conditions include: a reactant space velocity of 1–20 h⁻¹. -1 Preferably 2 to 10 hours -1 More preferably 2-4h -1 .

[0054] According to a preferred embodiment of the present invention, the reaction conversion conditions include: the reaction conversion is carried out in the presence of a hydrogen-containing protective agent; the amount of protective agent added is preferably 0.5 to 1% of the mixed light hydrocarbon feedstock based on the weight of hydrogen.

[0055] In this invention, the reaction protectant is a hydrogen-containing gas. The hydrogen is not consumed in the reaction process and only plays a role in inhibiting the reaction and reducing carbon buildup on the catalyst.

[0056] According to the present invention, the reaction protectant is preferably hydrogen.

[0057] According to a preferred embodiment of the present invention, the reaction conversion is carried out in two steps, and the temperature of the second reaction conversion is 50-80°C higher than the temperature of the first reaction conversion.

[0058] According to a preferred embodiment of the present invention, the first reaction conversion conditions include:

[0059] The reaction temperature is 250–400℃, preferably 280–350℃; and / or the reaction pressure is 0.05–2.0 MPa, preferably 0.1–1.5 MPa; and / or the space velocity of the reactants is 1–20 h⁻¹. -1 Preferably 2 to 10 hours -1 .

[0060] According to a preferred embodiment of the present invention, the second reaction conversion conditions include: a reaction temperature of 280–450°C, preferably 300–400°C; and / or a reaction pressure of 0.05–2.0 MPa, preferably 0.1–1.5 MPa; and / or a reactant space velocity of 1–20 h⁻¹. -1 Preferably 2 to 10 hours -1 .

[0061] The present invention has no special requirements for the mixed light hydrocarbons, but preferably the concentration of olefins in the mixed light hydrocarbons is 5-80% by mass fraction, and more preferably 15-70%.

[0062] According to a preferred embodiment of the present invention, the mixed light hydrocarbons include alkanes and olefins, preferably the alkanes are selected from one or more of n-butane and isoalkanes, and more preferably n-butane; preferably the olefins are selected from one or more of trans-butene-2, cis-butene-2, butene-1, and isobutene.

[0063] According to a preferred embodiment of the present invention, the mixed light hydrocarbons preferably include at least one butane selected from n-butane and isobutane, and at least one butene selected from trans-butene-2, cis-butene-2, butene-1, and isobutene.

[0064] In this invention, the composition and content of the mixed light hydrocarbons can be selected from a wide range. For this invention, a preferred method is...

[0065] Based on the total mass of the mixed light hydrocarbons, the olefin content is 15-70%, preferably 15-30%; the alkane content is 30-85%, preferably 70-85%.

[0066] In this invention, there are no special requirements for the steps and conditions of ammonium exchange, and they will not be described in detail here.

[0067] According to the present invention, a method for deolefination of mixed light hydrocarbons is provided. Under the action of a catalyst, the olefins in the mixed light hydrocarbons undergo reaction conversion, mainly producing heavier components with C5 and above, while the remaining C4 components are mainly alkane components. The SiO2 / Al2O3 molar ratio of the molecular sieve is 30-300, the reaction temperature is 250-450℃, the reaction pressure is 0.05-2.0 MPa, and the reactant space velocity is 1-20 h⁻¹. -1 .

[0068] According to the present invention, the preferred space velocity of the light hydrocarbon mixture is 2 to 10 h⁻¹. -1 .

[0069] According to the present invention, the preferred reaction temperature is preferably in the range of 280–400°C.

[0070] According to the present invention, preferably, the olefin in the mixed light hydrocarbon is selected from one or more of trans-butene, cis-butene, butene-1, and isobutene.

[0071] According to the present invention, the alkane in the mixed light hydrocarbons is preferably selected from one or two of n-butane and isoalkanes, and more preferably n-butane.

[0072] According to the present invention, the concentration of olefins in the mixed light hydrocarbons is preferably 5% to 80% by mass fraction.

[0073] This invention can use a mixture of light hydrocarbons with an appropriate olefin concentration as raw material, carry out the reaction in a small-scale reaction device, and directly introduce the reaction tail gas into an online gas chromatograph to sample and analyze the reaction products, calculate the reaction performance, and compare the technical effects of the technical solution of this invention.

[0074] According to the present invention, the method is particularly suitable for application in ethylene cracking.

[0075] Calculation method:

[0076] Butene conversion rate = (1 - total butene concentration in product / total butene concentration in feed) * 100%.

[0077] Examples 1-2

[0078] Catalyst preparation: Weigh 2.7 g of sodium hydroxide and dissolve it in 100 g of silica sol with a solid content of 40% by weight under stirring. Add the prepared sodium-containing silica sol to 100 g of NaZSM-5 molecular sieve raw powder (SiO2 / Al2O3 ratio of 100) and 3 g of guar gum powder, knead evenly, extrude into Φ2 cylinders, and obtain molecular sieve catalyst preforms by drying and calcining at 550℃.

[0079] 200 g of 30 wt% triethylamine solution was placed in a 1-liter autoclave, and 50 g of the above-mentioned preform was placed on the solution. The autoclave was sealed and heated to 130°C and held for 120 hours to perform binder-free treatment of the preform. Then, conventional ammonium exchange was performed 5 times at 90°C with 10 wt% ammonium sulfate solution. After drying, it was calcined at 550°C for 4 hours to obtain hydrogen-type molecular sieve HZSM-5 catalyst A.

[0080] Performance evaluation: Using mixed C4 as raw material, the composition of which is shown in Table 1, and HZSM-5 molecular sieve A without binder treatment as catalyst.

[0081] The reaction was carried out at a temperature of 350℃, a pressure of 1.5 MPa, and a mixed C4 weight hourly space velocity of 2 h⁻¹. -1 Under the condition of 10g catalyst loading, the deolefination effect of the catalyst on mixed C4 at different concentrations of hydrogen as a protective agent (0.5% wt% and 1% wt%) was evaluated. The reaction conditions are shown in Table 2, and the reaction results are shown in Table 3.

[0082] Table 1. Composition of test raw materials (content, weight %)

[0083]

[0084] Example 3

[0085] Using the same binder-free HZSM-5 molecular sieve A as in Example 1 as the catalyst and the same mixed C4 as the raw material, two reactors in series were used to evaluate the deolefination performance under different reaction conditions:

[0086] First reactor: 300℃, 1.5MPa, space velocity 4h -1 Hydrogen accounts for 1% of the weight of the imported raw materials for the reaction.

[0087] Second reactor: 350℃, 1.5MPa, space velocity 4h -1 Hydrogen accounts for 1% of the weight of the imported raw materials for the reaction.

[0088] The reaction results are shown in Table 3.

[0089] The reaction results show that the variable temperature segmented reaction process has a significant effect on improving the conversion rate of raw material olefins and reducing the olefin content of the product.

[0090] Examples 4-6

[0091] Using the same mixed C4 as in Example 1 above and the binder-free HZSM-5 molecular sieve A catalyst; the reaction was carried out at a temperature of 350°C and a mixed C4 weight hourly space velocity of 2 h⁻¹. -1 With a catalyst loading of 10g and under reaction conditions without hydrogen protection agent, the deolefination effect of the reaction under different catalyst pressures was evaluated. The reaction conditions are shown in Table 2, and the reaction results are shown in Table 3.

[0092] Examples 7-9

[0093] Using the same mixed C4 as in Example 1 above and HZSM-5 molecular sieve A catalyst without binder treatment, the deolefination effect of different mixed C4 catalysts was evaluated under the conditions of reaction temperature 350℃, pressure 0.6MPa, and catalyst loading 10g. The reaction conditions are shown in Table 2, and the reaction results are shown in Table 3.

[0094] Examples 10-13

[0095] The catalyst used was the same mixed C4 as in Example 1 above, and the HZSM-5 molecular sieve A catalyst was treated without binder.

[0096] The reaction was carried out at temperatures of 250℃, 300℃, 350℃, and 400℃, a pressure of 0.6 MPa, and a mixed C4 weight hourly space velocity of 10 h⁻¹. -1 With a catalyst loading of 10g, the deolefination effect of the catalyst at different reaction temperatures was evaluated. The reaction conditions are shown in Table 2, and the reaction results are shown in Table 3.

[0097] Examples 14-16

[0098] The HZSM-5 molecular sieve A catalyst, which underwent the same binderless treatment as in Example 1 above, was used; the reaction was carried out at a temperature of 350°C and a C4 liquid space velocity of 2 h⁻¹. -1 Under the conditions of reaction pressure of 1.5 MPa and catalyst loading of 10 g, the deolefination reaction effect of different mixed C4 feedstocks with total butene concentrations of 15.2%, 45.6% and 69.8% (composition shown in Table 1) was evaluated. The reaction results are shown in Table 3.

[0099] Examples 17-20

[0100] Catalyst preparation: The same catalyst preparation method as in Example 1 was used. NaZSM-5 molecular sieve raw powder with different SiO2 / Al2O3 ratios of 30, 60, 200 and 300 was kneaded and shaped using the same silica sol and method as in Example 1. The same catalyst treatment and activation preparation steps were then performed to obtain binder-free hydrogen-type molecular sieve catalysts with different SiO2 / Al2O3 ratios.

[0101] Catalyst evaluation: Using the same mixed C4 as in Example 1 as the raw material, the reaction was carried out at a temperature of 350°C, a reaction pressure of 1.5 MPa, and a C4 liquid hourly space velocity of 2 h⁻¹. -1 The catalyst debutene removal effect was evaluated under the condition of 10 grams of catalyst loading. The reaction results are shown in Table 3.

[0102] Example 21

[0103] Using the same binderless HZSM-5 molecular sieve A catalyst as in Example 1 above, and a mixed C5 catalyst (with a mixed pentene-1 content of 25.6% by weight (composition shown in Table 1)), the deolefination effect of the mixed C5 catalyst at a weight hourly space velocity (WHSV) of 2 was tested under reaction conditions of 350°C, 1.5 MPa, and 10 g catalyst loading. The reaction results are shown in Table 3. The deolefination effect of the C5 catalyst was also good.

[0104] Example 22

[0105] Catalyst preparation: 100g of silica sol with a solid content of 40% by weight was added to 100g of NaZSM-5 molecular sieve raw powder (SiO2 / Al2O3 ratio of 100) and 3g of guar gum powder, kneaded evenly, extruded into Φ2 cylinders, and obtained molecular sieve catalyst preforms by drying and calcining at 550℃.

[0106] 5g of tetrapropylammonium bromide, 10g of 1,6-hexanediamine, and 30g of distilled water were placed in a 1-liter autoclave. 10g of the above-mentioned preform was placed on top of the solution. The autoclave was sealed and heated to 180°C and held for 72 hours to perform binder-free treatment of the preform. Then, conventional ammonium exchange was performed 5 times at 90°C with a 10% ammonium sulfate solution. After drying, it was calcined at 550°C for 4 hours to obtain hydrogen-type molecular sieve HZSM-5 catalyst D.

[0107] The catalyst was evaluated according to the conditions of Example 1.

[0108] Table 2, Reaction Conditions

[0109]

[0110] As shown in Table 3, the binder-free molecular sieve catalyst of this invention contains virtually no inert binder material. It is a whole with a secondary pore structure formed by the interlocking of small molecular sieve crystals. The molecular sieve crystals are fully exposed without being encapsulated by binders. Therefore, the catalyst of this invention has the characteristics of good internal diffusion performance, high catalytic activity, and uniform distribution and consistent strength of active sites. Thus, it has a significant advantage in the deolefination reaction of light hydrocarbons, easily achieving an olefin conversion rate of over 90%. The C4 to C6 components of the product are primarily alkanes, with few other side reactions.

[0111] Table 3. Results of the deolefination reaction

[0112]

[0113] *The reaction feedstock is C5 light hydrocarbons. The olefin conversion rate and other properties are calculated based on the concentrations of pentene and pentane in the feedstock and products.

[0114] Because the binder-free molecular sieve catalyst of this invention contains virtually no inert binder material, and is a whole with a secondary pore structure formed by the interlocking of small molecular sieve crystals, the molecular sieve crystals are not encapsulated by binders and are fully exposed. Therefore, the catalyst of this invention has the characteristics of good internal diffusion performance, high catalytic activity, uniform distribution of active sites and basically consistent strength. Therefore, it has obvious advantages in the deolefination reaction of light hydrocarbons, the olefin conversion rate can easily reach more than 90%, the C4 to C6 components of the product are basically alkanes, and there are few other side reactions.

[0115] Comparative Example 1

[0116] Catalyst preparation: 100g of NaZSM-5 molecular sieve raw powder (SiO2 / Al2O3 ratio of 100) and 3g of guar gum powder were mixed evenly, and about 100g of silica sol with a solid content of 40% by weight was added as a binder. After kneading evenly, the mixture was extruded into strips, dried, and calcined at 550℃ to form a preform. Then, conventional ammonium exchange was performed and calcined at 550℃ for 4 hours to obtain hydrogen-type molecular sieve catalyst B.

[0117] Catalyst evaluation: Using mixed C4 (same as in Example 1) as raw material, the reaction was carried out at a temperature of 350°C, a reaction pressure of 1.5 MPa, and a C4 liquid hourly space velocity of 2 h⁻¹. -1 The catalyst loading was 10 grams. The catalyst conversion effect on butene was evaluated. The reaction results are shown in Table 3.

[0118] Comparative Example 2

[0119] Catalyst preparation: 100g of NaZSM-5 molecular sieve raw powder (SiO2 / Al2O3 ratio of 100), 70g of pseudoboehmite and 5g of guar gum powder were kneaded evenly, 100g of 1% wt% dilute nitric acid solution was added and kneaded evenly, and then extruded into Φ2 cylinders. After drying and calcination, the resulting material was subjected to ammonium exchange and activation treatment at 550℃ for 4 hours to obtain hydrogen-type molecular sieve catalyst C.

[0120] Catalyst evaluation: Using mixed C4 (same as in the example) as raw material, the reaction was carried out at a temperature of 350°C, a reaction pressure of 1.5 MPa, and a C4 liquid hourly space velocity of 2 h⁻¹. -1 The catalyst loading was 10 grams. The catalyst conversion effect on butene was evaluated. The reaction results are shown in Table 3.

[0121] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for deolefination of mixed light hydrocarbons, characterized in that, The method includes: reacting and converting olefins in a mixture of light hydrocarbons under the action of a catalyst to mainly generate higher-grade heavy components, with the remaining light hydrocarbons being primarily alkane components; wherein the catalyst is a binder-free molecular sieve catalyst; the mixed light hydrocarbons are a mixture of C4 and / or C5 hydrocarbons; the concentration of olefins in the mixed light hydrocarbons is 5-80% by mass fraction; and the reaction conversion conditions include a reaction temperature of 250-450℃.

2. The method according to claim 1, wherein, The content of alkane components in the remaining light hydrocarbons after the reaction is above 95% by weight; and / or The products of the reaction transformation contain more than 5% by weight of heavier components with C5 or higher carbon atoms.

3. The method according to claim 2, wherein, The content of alkane components in the remaining light hydrocarbons after the reaction is above 97% by weight; and / or The products of the reaction transformation contain 5-30% by weight of heavier components with C5 or more carbon atoms.

4. The method according to claim 1, wherein, The content of alkane components in the remaining light hydrocarbons after the reaction is more than 99% by weight.

5. The method according to claim 1, wherein, The binder-free molecular sieve catalyst is a shaped catalyst containing molecular sieves and binders, wherein the binder is crystallized and converted into the corresponding molecular sieve, and the binder content is less than 5% by weight.

6. The method according to claim 1, wherein, The preparation method of the binder-free molecular sieve catalyst includes: a) Under alkaline conditions, molecular sieve powder, binder, and optional extrusion aid are shaped, dried, and calcined to obtain a catalyst preform of the desired shape; b) Place the catalyst preform in a vapor containing an organic amine solution and perform solid-state crystallization treatment at 100-200°C for 24-240 hours; c) The crystallized embryo is subjected to ammonium exchange and calcination to obtain a hydrogen-type molecular sieve catalyst.

7. The method according to claim 6, wherein, In step b), the catalyst preform is placed in a vapor containing an organic amine solution and subjected to solid-state crystallization treatment at 120-140°C for 24-240 hours.

8. The method according to claim 7, wherein, In step b), the catalyst preform is placed in a vapor containing an organic amine solution and subjected to solid-state crystallization treatment at 120-140°C for 100-150 hours.

9. The method according to claim 6, wherein, Step a) is carried out in the presence of an alkali metal hydroxide.

10. The method according to claim 9, wherein, Step a) is carried out in the presence of sodium hydroxide.

11. The method according to claim 6, wherein, In step b), The organic amine is triethylamine; The concentration of the organic amine-containing solution is 20-40% by weight.

12. The method according to claim 6, wherein, In step b), The preparation method of the binder-free molecular sieve catalyst includes: a) In the presence of alkali metal hydroxides, molecular sieve powder, binder and extrusion aid are shaped, dried and calcined to obtain catalyst preforms of the desired shape; b) Place the catalyst preform in a vapor containing triethylamine solution and perform solid-state crystallization treatment at 100~200℃ for 24~240 hours; c) The crystallized embryo is subjected to ammonium exchange and calcination to obtain a hydrogen-type molecular sieve catalyst.

13. The method according to claim 12, wherein, In step b), The preparation method of the binder-free molecular sieve catalyst includes: a) In the presence of alkali metal hydroxides, molecular sieve powder, binder and extrusion aid are shaped, dried and calcined to obtain catalyst preforms of the desired shape; b) Place the catalyst preform in a vapor containing triethylamine solution and allow it to solidify at 120-140°C for 100-150 hours. c) The crystallized embryo is subjected to ammonium exchange and calcination to obtain a hydrogen-type molecular sieve catalyst.

14. The method according to claim 6, wherein, The preparation method of the binder-free molecular sieve catalyst includes: a) An alkali metal hydroxide is mixed with a binder to obtain an alkali metal sol, and then molecular sieve powder and extrusion aid are added to mix and extrude, dry and calcined to obtain a catalyst preform of the required shape. b) Place the catalyst preform in a vapor containing triethylamine solution and perform solid-state crystallization treatment at 100~200℃ for 24~240 hours; c) The crystallized embryo is subjected to ammonium exchange and calcination to obtain a hydrogen-type molecular sieve catalyst.

15. The method according to claim 14, wherein, The preparation method of the binder-free molecular sieve catalyst includes: a) An alkali metal hydroxide is mixed with a binder to obtain an alkali metal sol, and then molecular sieve powder and extrusion aid are added to mix and extrude, dry and calcine to obtain a catalyst preform of the required shape. b) Place the catalyst preform in a vapor containing triethylamine solution and perform solid-state crystallization treatment at 120-140℃ for 100-150 hours; c) The crystallized embryo is subjected to ammonium exchange and calcination to obtain a hydrogen-type molecular sieve catalyst.

16. The method of claim 14, wherein, The weight ratio of alkali metal hydroxide, binder (calculated as oxide), molecular sieve raw powder and extrusion aid is 1-3:30-50:100:1-5; The weight ratio of triethylamine solution to catalyst preform is 3-5:

1.

17. The method according to claim 6, wherein, The molecular sieve is at least one of mordenite, MCM-22, MCM-23, MCM-49, MCM-56, ZSM-5, ZSM-11, ZSM-23, ZSM-35, β, and Y; and / or The SiO2 / Al2O3 molar ratio of the molecular sieve is 30~300; and / or The adhesive is silica sol; and / or The extrusion aid is guar gum powder.

18. The method according to claim 17, wherein, The molecular sieve is ZSM-5 and / or ZSM-11; and / or The SiO2 / Al2O3 molar ratio of the molecular sieve is 30~200; and / or The solid content of the silica sol is 30-50% by weight.

19. The method according to claim 18, wherein, The molecular sieve is ZSM-5; and / or The SiO2 / Al2O3 molar ratio of the molecular sieve is 30~60.

20. The method according to claim 1, wherein, The conditions for the reaction transformation include: The reaction temperature is 280–400℃; and / or The reaction pressure is 0.05–2.0 MPa; and / or The space velocity of the reactants is 1~20 h⁻¹ -1 .

21. The method according to claim 20, wherein, The conditions for the reaction transformation include: The reaction temperature is 280–400℃; and / or The reaction pressure is 0.1–1.5 MPa; and / or The space velocity of the reactants is 2-10 h⁻¹ -1 .

22. The method according to claim 1, wherein, The conditions for the reaction transformation include: The reaction conversion is carried out in the presence of a hydrogen-containing protective agent; the amount of protective agent added is 0.5 to 1% of the mixed light hydrocarbon feedstock by weight of hydrogen.

23. The method according to claim 1, wherein, The reaction transformation occurs in two steps. The temperature of the second reaction is 50-80°C higher than that of the first reaction.

24. The method according to claim 23, wherein, The conditions for the first reaction conversion include: The reaction temperature is 250–400℃; and / or The reaction pressure is 0.05–2.0 MPa; and / or The space velocity of the reactants is 1~20 h⁻¹ -1 ; The conditions for the second reaction conversion include: The reaction temperature is 280–450 °C; and / or The reaction pressure is 0.05–2.0 MPa; and / or The space velocity of the reactants is 1~20 h⁻¹ -1 .

25. The method according to claim 24, wherein, The conditions for the first reaction conversion include: The reaction temperature is 280–350 °C; and / or The reaction pressure is 0.1–1.5 MPa; and / or The space velocity of the reactants is 2-10 h⁻¹ -1 ; The conditions for the second reaction conversion include: The reaction temperature is 300–400℃; and / or The reaction pressure is 0.1–1.5 MPa; and / or The space velocity of the reactants is 2-10 h⁻¹ -1 .

26. The method according to claim 1, wherein, The concentration of olefins in the mixed light hydrocarbons is 15-70% by mass fraction; The mixed light hydrocarbons include alkanes and olefins.

27. The method according to claim 26, wherein, The alkane is selected from one or more of n-butane and isobutane; the olefin is selected from one or more of trans-butene-2, cis-butene-2, butene-1, and isobutene.

28. The method according to claim 27, wherein, The alkane is selected from n-butane.

29. The method according to claim 1, wherein, The mixed light hydrocarbons include at least one butane selected from n-butane and isobutane, and at least one butene selected from trans-butene-2, cis-butene-2, butene-1, and isobutene.

30. The method according to claim 1, wherein, Based on the total mass of the mixed light hydrocarbons, the olefin content is 15-70% and the alkane content is 30-85%.

31. The method according to claim 30, wherein, Based on the total mass of the mixed light hydrocarbons, the olefin content is 15-30% and the alkane content is 70-85%.

32. The application of the method according to any one of claims 1-31 in ethylene cracking.

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