An ethylene oligomerization switchable production of 1-butene and 1-hexene system

Abstract

This invention belongs to the field of 1-butene and 1-hexene preparation technology, and relates to a switchable system for preparing 1-butene and 1-hexene by ethylene oligomerization, comprising: a reactor, a deethyleneization tower, a circulating gas compressor, a butene tower, a hexene tower, and a solvent recovery tower. The ethylene oligomerization system provided in this application uses ethylene as a raw material and can produce both 1-butene and 1-hexene in one system. It can be flexibly switched according to the downstream polyethylene unit's demand for comonomers, producing high-quality 1-butene / 1-hexene monomers on demand. Furthermore, the system has a simple process flow and features safety, stable operation, low investment, superior product quality, low material and energy consumption, and long operating cycle.

Description

Technical Field

[0001] This invention relates to the field of 1-butene and 1-hexene preparation technology, and more particularly to an ethylene oligomerization system for switching the preparation of 1-butene and 1-hexene. Background Technology

[0002] 1-Butene and 1-hexene are the main comonomers in the production of industrial low-density polyethylene (LLDPE) and high-density polyethylene (HDPE). Their short, side-branched structure, acting as tie molecules, imparts stronger bonding between polyethylene flakes, significantly improving the tensile strength, impact strength, tear resistance, and other mechanical properties of polyethylene products. In industrial processes, 1-10% of these comonomers are typically added to produce copolymer polyethylene.

[0003] Compared to developed countries, domestic polyethylene production mainly uses 1-butene as a comonomer, while over 70% of imported mid-to-high-end polyethylene products are 1-hexene-based. The product structure needs further optimization. Considering the current situation of the North American and Western European markets and the domestic polyethylene market, it is expected that domestic polyethylene production will gradually shift from being dominated by 1-butene to 1-hexene-based products in the future, especially as the mature application of metallocene catalyst technology will increase the demand for 1-hexene.

[0004] China consumes a large amount of 1-butene comonomers, primarily obtained from the separation of mixed C4 feedstocks from ethylene cracking units. However, this route for producing polymer-grade 1-butene suffers from difficulties in separation and high impurity content. In recent years, significant changes have occurred in the domestic C4 industry, leading to a growing scarcity of mixed C4 feedstocks, severely impacting the production of 1-butene from cracked C4 feedstocks. The technology for producing 1-butene from ethylene offers advantages such as high product purity and low processing costs. Previously, its industrial application in China was relatively limited due to the high cost of ethylene feedstocks. However, with the industrialization of technologies such as coal-to-olefins (MTO) and ethane-to-ethylene in recent years, the production of high-quality comonomers from low-cost ethylene not only solves the monomer demand for polyethylene plants but also offers low-cost, economically viable comonomers with broad application prospects.

[0005] However, most of the newly built polyethylene plants in China have 1-hexene and 1-butene products, and for most plants, except for special considerations, it is generally impossible to meet the demand for comonomers for polyethylene plants at the same time. Summary of the Invention

[0006] In view of this, the present invention provides a system for switching the preparation of 1-butene and 1-hexene by ethylene oligomerization.

[0007] Specifically, the present invention is achieved through the following technical solution:

[0008] According to a first aspect of the present invention, a system for switching the production of 1-butene and 1-hexene by ethylene oligomerization is provided, comprising:

[0009] A reactor for receiving a predetermined ratio of ethylene, solvent, and catalyst and for the reaction to take place;

[0010] A deethyleneization tower is used to remove unreacted ethylene from the reactants obtained from the reactor; the deethyleneization tower is connected to the reactor;

[0011] A recirculating gas compressor is used to extract unreacted ethylene from the deethyleneization tower and deliver it to the reactor; the recirculating gas compressor is connected to both the reactor and the deethyleneization tower.

[0012] The butene tower is used to receive the reactants conveyed by the deethylene tower and separate them to obtain 1-butene product; the 1-butene tower is connected to both the deethylene tower and the reactor.

[0013] Hexene tower, used to receive the reactants conveyed by the deethylene tower and separate them to obtain 1-hexene product; the 1-hexene tower is connected to the deethylene tower;

[0014] A solvent recovery tower is used to receive 1-hexene separated by the 1-hexene tower and transport it to the reactor; the solvent recovery tower is connected to both the reactor and the 1-hexene tower.

[0015] Optionally, it also includes: a 1-butene storage tank, which is connected to the top of the 1-butene tower and the reactor, respectively.

[0016] Optionally, it further includes: a 1-butene cooler, which is connected to the top of the 1-butene storage tank and the 1-butene tower, respectively.

[0017] Optionally, it further includes: a 1-butene transfer pump, which is connected to the top of the 1-butene tower, the reactor, and the 1-butene storage tank, respectively.

[0018] Optionally, it also includes: a 1-hexene storage tank, the 1-hexene storage tank being connected to the top of the 1-hexene tower.

[0019] Optionally, it further includes: a 1-hexene cooler, which is connected to the top of the 1-hexene storage tank and the 1-hexene tower, respectively.

[0020] Optionally, it also includes: a 1-hexene transfer pump, which is connected to the top of the 1-hexene tower and the 1-hexene storage tank, respectively.

[0021] Optionally, it further includes a solvent storage tank, which is connected to the top of the solvent recovery tower and the reactor, respectively.

[0022] Optionally, it further includes a solvent cooler connected to the top of both the solvent storage tank and the solvent recovery tower.

[0023] Optionally, it further includes a solvent delivery pump, which is connected to the top of the solvent recovery tower, the reactor, and the solvent storage tank, respectively.

[0024] The technical solution provided by this invention brings at least the following beneficial effects:

[0025] This application provides a system for switching the production of 1-butene and 1-hexene from ethylene oligomerization. Using ethylene as a raw material, this system can produce both 1-butene and 1-hexene in one unit, and can be flexibly switched according to the demand for comonomers from downstream polyethylene units, producing high-quality 1-butene / 1-hexene monomers on demand. At the same time, the process technology of this system is simple, safe and complete, stable in operation, low in investment, superior product quality, low in material and energy consumption, and long in operation cycle. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of a system for preparing 1-butene and 1-hexene by switching between ethylene oligomerization, as provided in an embodiment of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Figure 1The illustration schematically depicts a system for the switchable preparation of 1-butene and 1-hexene using ethylene oligomerization, applicable to embodiments of the present invention.

[0031] Reference Figure 1 As shown, this application provides a system for switching the production of 1-butene and 1-hexene by ethylene oligomerization, comprising:

[0032] Reactor 1 is used to receive ethylene, solvent and catalyst in a preset ratio and react therein;

[0033] Ethylene removal tower 2 is used to remove unreacted ethylene from the reactants obtained from reactor 1; the ethylene removal tower 2 is connected to reactor 1;

[0034] A circulating gas compressor 3 is used to extract unreacted ethylene from the deethyleneization tower 2 and deliver it to the reactor 1; the circulating gas compressor 3 is connected to both the reactor 1 and the deethyleneization tower 2.

[0035] 1-Butene tower 4 is used to receive the reactants conveyed by the deethylene tower 2 and separate them to obtain 1-butene product; the 1-butene tower 4 is connected to the deethylene tower 2 and the reactor 1 respectively.

[0036] 1-Hexene tower 5 is used to receive the reactants conveyed by the deethylene tower 2 and separate them to obtain 1-hexene product; the 1-hexene tower 5 is connected to the deethylene tower 2;

[0037] Solvent recovery tower 6 is used to receive 1-hexene separated by 1-hexene tower 5 and transport it to reactor 1; solvent recovery tower 6 is connected to reactor 1 and 1-hexene tower 5 respectively.

[0038] In this embodiment, ethylene, solvent, and catalyst are introduced into reactor 1 in a specific ratio. Under the action of the catalyst, when in 1-butene mode, ethylene undergoes dimerization in reactor 1 to generate 1-butene; when in 1-hexene mode, ethylene undergoes trimerization in reactor 1 to generate 1-hexene. The reacted material is sent to deethyleneization tower 2, and unreacted ethylene is returned to reactor 1 from the top of deethyleneization tower 2 via circulating gas compressor 3. When in 1-butene mode, the bottom liquid in deethyleneization tower 2 is sent to 1-butene tower 4; when in 1-hexene mode, the bottom liquid in deethyleneization tower 2 is sent to 1-hexene tower 5. When in 1-butene mode, after separation in 1-butene tower 4, the product is cooled at the top of the tower to obtain 1-butene product. After pressurization, part of it is returned to the top of the tower as reflux, part is returned to reactor 1 as circulating solvent, and part is sent out as product. The bottom of the tower contains a heavy component rich in mixed C6 olefins, which is pumped out of the boundary. When operating under 1-hexene conditions, after separation in 1-hexene column 5, the product is cooled at the top of the column to obtain 1-hexene product. After pressurization, a portion is returned to the top of the column as reflux, and the portion is sent out as product. The bottom liquid in 1-hexene column 5 is sent to the solvent recovery column. After separation in solvent recovery column 6, the product is cooled at the top of the column to obtain cyclohexane solvent. After pressurization, a portion is returned to the top of the column as reflux, and the portion is sent back to reactor 1 as circulating solvent. The bottom of the column contains a heavy component rich in mixed C10 olefins, which is pumped out of the boundary area.

[0039] This application presents a system for the switchable production of 1-butene and 1-hexene from ethylene oligomerization, including key components such as a reactor, a deethyleneization tower, a circulating gas compressor, a butene tower, a hexene tower, and a solvent recovery tower, and achieves the following innovations:

[0040] Flexible production capacity: The system uses ethylene as raw material, and an oligomerization reaction occurs in the reactor with a preset ratio of solvent and catalyst to generate reactants containing 1-butene and 1-hexene. Through the separation action of the butene tower and the hexene tower, the system can flexibly switch to produce 1-butene or 1-hexene as needed, meeting the current diversified needs of downstream polyethylene plants for comonomers.

[0041] Ethylene and solvent recycling: The deethyleneization tower removes unreacted ethylene from the reactor, while the recycle gas compressor returns the unreacted ethylene to the reactor, achieving ethylene recycling and reducing material consumption. The solvent recovery tower recovers unreacted solvent from the reaction process and returns it to the reactor for reuse, further reducing material and energy consumption.

[0042] Simple and efficient process flow: The system's process technology is simple, with compact connections between components, convenient operation, and features safety, stability, and reliable performance. By optimizing component design and layout, the system achieves superior product quality and low material and energy consumption, while also extending operating cycles, thus reducing production and maintenance costs.

[0043] Significant market competitiveness: This system can flexibly switch between producing 1-butene or 1-hexene according to market demand, and can also provide high-quality comonomer products, meeting the polyethylene industry's need for high-quality raw materials. By reducing material consumption, energy consumption, and production costs, this system enhances the market competitiveness of its products and provides strong support for the development of the polyethylene industry.

[0044] In summary, the system for switching the production of 1-butene and 1-hexene via ethylene oligomerization proposed in this embodiment represents a significant improvement and enhancement over existing technologies in the field of ethylene oligomerization for the production of 1-butene and 1-hexene. This is achieved through innovations such as flexible production capacity switching, recycling of ethylene and solvents, a simple and efficient process flow, and significant market competitiveness. These innovations not only solve the problems of single product, high material and energy consumption, and unstable product quality in traditional preparation methods, but also meet the current market demand for flexible use of multiple comonomers.

[0045] For example, the ethylene oligomerization switchable production system for 1-butene and 1-hexene provided in this application further includes: a 1-butene storage tank, which is connected to the top of the 1-butene tower 4 and the reactor 1, respectively.

[0046] In this embodiment, a portion of the 1-butene product in the 1-butene column 4 is stored in a 1-butene storage tank via the top of the column. The 1-butene storage tank is connected to both the top of the 1-butene column and the reactor, and is used to store the 1-butene product separated from the 1-butene column. This design helps to balance the supply and demand relationship in the production process, ensuring a stable supply of 1-butene products.

[0047] For example, the ethylene oligomerization switchable production system for 1-butene and 1-hexene provided in this application further includes: a 1-butene cooler, which is connected to the top of the 1-butene storage tank and the top of the 1-butene tower 4, respectively.

[0048] In this embodiment, a 1-butene cooler is used to cool the 1-butene discharged from the top of the 1-butene tower 4. The 1-butene cooler is connected to the 1-butene storage tank and the top of the 1-butene tower, and is used to cool the 1-butene discharged from the 1-butene tower. Cooled 1-butene is easier to store and transport, and also helps to reduce losses during storage and transportation.

[0049] For example, the ethylene oligomerization switchable system for preparing 1-butene and 1-hexene provided in this application further includes: a 1-butene delivery pump, which is connected to the top of the 1-butene tower 4, the reactor 1 and the 1-butene storage tank respectively.

[0050] In this embodiment, the 1-butene transfer pump pressurizes the 1-butene supplied from the 1-butene storage tank, then feeds a portion into the 1-butene tower 4 and a portion into the reactor 1. The 1-butene transfer pump is connected to the top of the 1-butene tower, the reactor, and the 1-butene storage tank, respectively, achieving efficient transport of 1-butene during production, storage, and reuse. This design allows the system to flexibly transfer 1-butene from the storage tank back to the reactor for reuse, or to transport the product to downstream polyethylene plants.

[0051] For example, the ethylene oligomerization switchable system for preparing 1-butene and 1-hexene provided in this application further includes: a 1-hexene storage tank, which is connected to the top of the 1-hexene tower 5.

[0052] In this embodiment, a portion of the 1-hexene product in the 1-hexene column 5 is stored in a 1-hexene storage tank via the top of the column. The 1-hexene storage tank is connected to the top of the 1-hexene column and is used to store the 1-hexene product separated from the 1-hexene column. This design helps ensure a stable supply of 1-hexene product.

[0053] For example, the ethylene oligomerization switchable production system for 1-butene and 1-hexene provided in this application further includes: a 1-hexene cooler, which is connected to the top of the 1-hexene storage tank and the 1-hexene tower 5, respectively.

[0054] In this embodiment, a 1-hexene cooler is used to cool the 1-hexene discharged from the top of the 1-hexene tower 5. The 1-hexene cooler is connected to the 1-hexene storage tank and the top of the 1-hexene tower, and is used to cool the 1-hexene discharged from the 1-hexene tower. Cooled 1-hexene is easier to store and transport, and also helps to reduce losses during storage and transportation.

[0055] For example, the ethylene oligomerization switchable system for preparing 1-butene and 1-hexene provided in this application further includes: a 1-hexene delivery pump, which is connected to the top of the 1-hexene tower 5 and the 1-hexene storage tank, respectively.

[0056] In this embodiment, the 1-hexene transfer pump pressurizes the 1-hexene supplied from the 1-hexene storage tank, and a portion of it is then fed into the 1-hexene tower 5. The 1-hexene transfer pump is connected to both the top of the 1-hexene tower and the 1-hexene storage tank, achieving efficient transport of 1-hexene during production, storage, and reuse. This design allows the system to flexibly transport 1-hexene products to downstream polyethylene plants.

[0057] For example, the ethylene oligomerization switchable production system for 1-butene and 1-hexene provided in this application further includes: a solvent storage tank, which is connected to the top of the solvent recovery tower 6 and the reactor 1 respectively.

[0058] In this embodiment, the solvent in the solvent recovery tower 6 is stored in a solvent storage tank via the top of the tower. The solvent storage tank is connected to both the top of the solvent recovery tower and the reactor, and is used to store the recovered solvent for reuse.

[0059] For example, the ethylene oligomerization switchable production system for 1-butene and 1-hexene provided in this application further includes: a solvent cooler, which is connected to the top of the solvent storage tank and the solvent recovery tower 6, respectively.

[0060] In this embodiment, a solvent cooler is used to cool the solvent discharged from the top of the solvent recovery tower 6. The solvent cooler is connected to both the solvent storage tank and the top of the solvent recovery tower, and is used to cool the hot solvent discharged from the solvent recovery tower. The cooled solvent is easier to store and reuse.

[0061] For example, the ethylene oligomerization switchable production system for 1-butene and 1-hexene provided in this application further includes: a solvent delivery pump, which is connected to the top of the solvent recovery tower 6, the reactor 1 and the solvent storage tank respectively.

[0062] In this embodiment, the solvent delivery pump pressurizes the solvent delivered by the solvent recovery tower 6, with a portion flowing into the solvent recovery tower 6 and a portion flowing into the reactor 1. The solvent delivery pump is connected to the top of the solvent recovery tower, the reactor, and the solvent storage tank, respectively, achieving efficient delivery of the solvent during the recovery, storage, and reuse processes.

[0063] This application provides a system for switching between ethylene oligomerization to produce 1-butene and 1-hexene, which features a short process flow, low raw material and utility consumption, safe control of reaction parameters, high product quality, and long operating cycle. It can produce both 1-butene and 1-hexene, allowing for flexible switching according to needs. In 1-butene mode, it exhibits high selectivity, high product purity, and low impurity content, meeting the comonomer requirements of polyethylene plants. In 1-hexene mode, it also offers high selectivity and high product purity, meeting the purity requirements of metallocene catalyst-based ethylene polymerization processes. Furthermore, it boasts a high single-pass ethylene conversion rate, and unreacted ethylene can be recycled.

[0064] This application provides a system for switching the production of 1-butene and 1-hexene from ethylene oligomerization. Using ethylene as a raw material, this system can produce both 1-butene and 1-hexene in one unit, and can be flexibly switched according to the demand for comonomers from downstream polyethylene units, producing high-quality 1-butene / 1-hexene monomers on demand. At the same time, the process technology of this system is simple, safe and complete, stable in operation, low in investment, superior product quality, low in material and energy consumption, and long in operation cycle.

[0065] It should be noted that in this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are mainly for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0066] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0067] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0068] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0069] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A system for switching the production of 1-butene and 1-hexene by ethylene oligomerization, characterized in that, include: A reactor for receiving a predetermined ratio of ethylene, solvent, and catalyst and for the reaction to take place; An ethylene removal tower is used to remove unreacted ethylene from the reactants obtained from the reactor. The deethylene tower is connected to the reactor; A recirculating gas compressor is used to extract unreacted ethylene from the deethyleneization tower and deliver it to the reactor; the recirculating gas compressor is connected to both the reactor and the deethyleneization tower. The butene tower is used to receive the reactants conveyed by the deethylene tower and separate them to obtain 1-butene product; the 1-butene tower is connected to both the deethylene tower and the reactor. Hexene tower, used to receive the reactants conveyed by the deethylene tower and separate them to obtain 1-hexene product; the 1-hexene tower is connected to the deethylene tower; A solvent recovery tower is used to receive 1-hexene separated by the 1-hexene tower and transport it to the reactor; the solvent recovery tower is connected to both the reactor and the 1-hexene tower.

2. The ethylene oligomerization system for switchable preparation of 1-butene and 1-hexene according to claim 1, characterized in that, Also includes: A 1-butene storage tank is connected to the top of the 1-butene tower and the reactor, respectively.

3. The ethylene oligomerization system for switchable preparation of 1-butene and 1-hexene according to claim 2, characterized in that, Also includes: A 1-butene cooler is connected to the top of the 1-butene storage tank and the 1-butene tower, respectively.

4. The ethylene oligomerization system for switchable preparation of 1-butene and 1-hexene according to claim 2, characterized in that, Also includes: A 1-butene transfer pump is connected to the top of the 1-butene tower, the reactor, and the 1-butene storage tank.

5. The ethylene oligomerization system for switchable preparation of 1-butene and 1-hexene according to claim 1, characterized in that, Also includes: A 1-hexene storage tank, which is connected to the top of the 1-hexene tower.

6. The ethylene oligomerization system for switchable preparation of 1-butene and 1-hexene according to claim 5, characterized in that, Also includes: A 1-hexene cooler is connected to the top of both the 1-hexene storage tank and the 1-hexene tower.

7. The ethylene oligomerization system for switchable preparation of 1-butene and 1-hexene according to claim 5, characterized in that, Also includes: A 1-hexene transfer pump is connected to the top of the 1-hexene tower and the 1-hexene storage tank, respectively.

8. The ethylene oligomerization system for switchable preparation of 1-butene and 1-hexene according to claim 1, characterized in that, Also includes: A solvent storage tank is connected to the top of the solvent recovery tower and the reactor, respectively.

9. The ethylene oligomerization system for switchable preparation of 1-butene and 1-hexene according to claim 8, characterized in that, It also includes a solvent cooler, which is connected to the top of the solvent storage tank and the solvent recovery tower, respectively.

10. The ethylene oligomerization system for switchable preparation of 1-butene and 1-hexene according to claim 8, characterized in that, Also includes: A solvent delivery pump is connected to the top of the solvent recovery tower, the reactor, and the solvent storage tank, respectively.

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