A piping structure for a butadiene extraction device

Abstract

The utility model provides a kind of butadiene extraction device pipeline structure, it is related to butadiene extraction technical field, including transport pipeline and supplementary pipeline, the transport pipeline is used to transport 1,3-butadiene, the transport pipeline has receiving end and discharge end, detection instrument for detecting 1,3-butadiene content is provided on the transport pipeline;The supplementary pipeline is used to transport 1,3-butadiene with higher concentration than 1,3-butadiene concentration in the transport pipeline to the transport pipeline, the supplementary pipeline has first end and second end, the first end is communicated with the transport pipeline, and the first end is connected to the transport pipeline between the receiving end and the detection instrument.Such can when detection instrument detects 1,3-butadiene content has downward trend, the work material of higher concentration 1,3-butadiene is introduced into transport pipeline through supplementary pipeline, to improve the content of 1,3-butadiene in transport pipeline.

Description

Technical Field

[0001] This utility model relates to the field of butadiene technology, and in particular to a pipeline structure for a butadiene extraction device. Background Technology

[0002] 1,3-Butadiene is an important chemical raw material, industrially obtained mainly from the C4 fraction, a byproduct of ethylene cracking. Due to the complexity and similar boiling points of the cracked C4 fraction, the acetonitrile method is commonly used for extractive distillation. This process typically includes two stages of extractive distillation and two stages of conventional distillation to obtain the polymer-grade product.

[0003] The traditional acetonitrile process is designed based on naphtha cracking C4 feedstock, which has a high 1,3-butadiene content (approximately 45%). However, with the trend towards lighter feedstocks in ethylene cracking (such as the extensive use of ethane), the 1,3-butadiene content in the by-product cracked C4 is continuously and significantly decreasing (down to around 35%). This fundamental change in feedstock concentration poses a serious challenge to existing plants. To process more feedstock to obtain an equivalent amount of product, the plant's processing capacity approaches saturation, leading to a significant increase in energy and material consumption. Simultaneously, the process operating window narrows, making product yield and purity control difficult, and increasing operational stability and safety risks. This problem urgently needs to be addressed. Utility Model Content

[0004] This invention provides a butadiene extraction device pipeline structure to solve the technical problem that the content of 1,3-butadiene in the current by-product cracked C4 is continuously and significantly decreasing, leading to difficulties in controlling product yield and purity, and increasing risks to operational stability and safety.

[0005] This utility model provides a butadiene extraction device pipeline structure, including: A transport pipeline for transporting 1,3-butadiene, the transport pipeline having a receiving end and a discharging end, and a detector for detecting the content of 1,3-butadiene is installed on the transport pipeline; A supplementary pipeline is provided for supplying 1,3-butadiene at a concentration higher than that in the transport pipeline to the transport pipeline. The supplementary pipeline has a first end and a second end, the first end being connected to the transport pipeline and connected to the transport pipeline between the receiving end and the detector.

[0006] In one embodiment of this utility model, a regulating valve is provided on the replenishment pipeline, and the regulating valve is used to regulate the flow rate on the replenishment pipeline.

[0007] In one embodiment of the present invention, a flow meter for measuring the flow rate on the supplementary pipeline is further provided on the supplementary pipeline, and the flow meter is electrically connected to the regulating valve.

[0008] In one embodiment of this utility model, the flow meter is also electrically connected to the detector.

[0009] In one embodiment of this utility model, a one-way valve is also provided on the replenishment pipeline, through which the working material in the replenishment pipeline flows from the second end to the first end.

[0010] In one embodiment of the present invention, the one-way valve is positioned near the first end of the supplementary pipeline, relative to the second end.

[0011] In one embodiment of this utility model, the supplementary pipeline is connected to the top of the heavy removal tower or the bottom of the light removal tower.

[0012] In one embodiment of this utility model, a pump is provided on the supplementary pipeline near the second end.

[0013] In one embodiment of this utility model, the detector is a gas chromatograph.

[0014] The beneficial effects of this utility model are as follows: The butadiene extraction device pipeline structure proposed in this utility model, by setting up a supplementary pipeline connected to the transport pipeline, can introduce a higher concentration of 1,3-butadiene into the transport pipeline when the detector detects a decreasing trend in the 1,3-butadiene content, thereby increasing the 1,3-butadiene content in the transport pipeline, ensuring the stable operation of subsequent processes, and meeting the production goal of "safe, stable, long-term, full-capacity, and high-quality". Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0016] In the attached diagram: Figure 1 This is a schematic diagram of the pipeline structure of a butadiene extraction device provided in an embodiment of the present invention.

[0017] The attached diagram is labeled as follows: 1. Supplementary pipeline; 2. Check valve; 3. Transport pipeline; 4. Detector; 5. Raw material evaporator; 6. Pump; 7. Flow meter; 8. Regulating valve. Detailed Implementation

[0018] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0019] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0020] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present invention.

[0021] 1,3-Butadiene is an olefin compound, one of the commonly referred to "three olefins" (ethylene, propylene, and butadiene), and belongs to petrochemical products.

[0022] Cracked C4 refers to a mixture of hydrocarbons containing four carbon atoms. Saturated hydrocarbons include n-butane and isobutane, while alkenes include 1-butene, 2-butene (cis- and trans-2-butene), isobutene, and butadiene. Other alkynes include ethylacetylene (1-butyne), 2-butyne, and vinylacetylene. Common feedstocks for ethylene cracking units include naphtha, ethane, coal / methanol (MTO), LPG, and crude diesel. All of these feedstocks produce cracked C4 during the ethylene cracking process. Due to the numerous isomers of cracked C4, the composition of cracked C4 varies significantly depending on the source (i.e., the feedstock for ethylene cracking units). Common cracked C4s and their corresponding components are shown in Table 1 below. Table 1 Comparison of C4 components from different sources of pyrolysis

[0023] Table 1 shows that the composition of C4 cracked carbon atoms varies under different feedstocks, especially the composition of butadiene. Among the feedstocks listed in Table 1, naphtha and crude diesel oil cracking yields C4 carbon atoms with higher butadiene content, and butadiene can be cracked to produce ethylene.

[0024] Currently, due to issues such as the economics, cracking difficulty, and ethylene yield of crude diesel cracking to produce ethylene, there are relatively few units using crude diesel cracking to produce ethylene. Most plants use naphtha cracking to obtain butadiene, which is then cracked to obtain ethylene. However, in recent years, due to the continuous growth of global ethane production and the low price of ethane, coupled with the higher ethylene yield from cracking ethane and other light feedstocks, it has a significant cost advantage over naphtha cracking to produce ethylene. The cracking process of ethane and other light feedstocks produces fewer byproducts that are easier to handle. During the cracking of ethane and propane, the majority of the products are light hydrocarbons (such as ethylene and propylene) and small amounts of methane, hydrogen, and other gases. In contrast, the cracking of heavy feedstocks such as naphtha produces complex heavy hydrocarbons (such as aromatics and coke). The separation and treatment of these byproducts increases the complexity and cost of the process. At the same time, the amount of coke produced during the cracking of light feedstocks is less, resulting in less equipment coking problems and reducing the frequency of downtime for cleaning and maintenance. Therefore, most plants add ethane during ethylene production to reduce production costs and achieve better economic benefits.

[0025] Furthermore, the cracking process of light feedstocks such as ethane has lower energy consumption and carbon emissions, which aligns with increasingly stringent global environmental regulations and the goal of sustainable development. The cracking of heavy feedstocks, on the other hand, not only consumes more energy and emits more carbon, but also produces more harmful substances (such as sulfur dioxide and nitrogen oxides), leading to greater environmental pressure and treatment costs.

[0026] Currently, there is a clear trend towards diversification and lighter feedstocks in ethylene production. Lighter feedstocks, such as ethane and propane, are more economical and efficient than heavier feedstocks, such as naphtha and diesel. All these factors have driven the shift in ethylene production feedstocks from heavy to light feedstocks.

[0027] Currently, most factories use the acetonitrile-based C4 cracking extraction technology to produce butadiene. This technology uses acetonitrile as a solvent and employs a two-stage extractive distillation and a two-stage conventional distillation method to separate polymer-grade 1,3-butadiene from cracked C4. This process design is based on using cracked C4 (approximately 45% 1,3-butadiene content) as a feedstock, a byproduct of naphtha cracking. However, to adapt to the trend of shifting ethylene production feedstocks from heavy to light feedstocks, in actual production, due to changes in upstream feedstocks, the 1,3-butadiene content in the cracked C4 feedstock has gradually decreased from 42% to approximately 35%, especially with the introduction of low-temperature ethane feedstock into the ethylene cracking unit, where the 1,3-butadiene content will continue to decrease. However, most of the ethylene cracking units in the factory are designed for a 1,3-butadiene content of around 45%. Therefore, when the 1,3-butadiene content is much less than 45% when the ethylene cracking unit is introduced, it will pose a severe challenge to the safe, stable, long-term, full-capacity and high-quality production operation of the unit.

[0028] Please see Figure 1 , Figure 1 This invention provides a butadiene extraction device pipeline structure, comprising a transport pipeline 3 and a replenishment pipeline 1. The transport pipeline 3 is used to transport 1,3-butadiene and has a receiving end and a discharging end. A detector 4 for detecting the 1,3-butadiene content is installed on the transport pipeline 3. The replenishment pipeline 1 is used to supply 1,3-butadiene at a concentration higher than that in the transport pipeline 3. The replenishment pipeline 1 has a first end and a second end. The first end is connected to the transport pipeline 3 and is connected to the transport pipeline 3 between the receiving end and the detector 4. By providing the replenishment pipeline 1 connected to the transport pipeline 3, when the detector 4 detects a decreasing trend in the 1,3-butadiene content, a higher concentration of 1,3-butadiene can be introduced into the transport pipeline 3 through the replenishment pipeline 1 to increase the 1,3-butadiene content in the transport pipeline 3, ensuring the stable operation of subsequent processes and meeting the production target of "safe, stable, long-term, full-capacity, and high-quality" production.

[0029] In an exemplary embodiment, a regulating valve 8 is provided on the replenishment line 1, which is used to regulate the flow rate on the replenishment line 1. The flow rate of the feed material (containing 1,3-butadiene) on the replenishment line 1 can be conveniently adjusted by the regulating valve 8.

[0030] In an exemplary embodiment, a flow meter 7 for measuring the flow rate on the supplementary pipeline 1 is also provided on the supplementary pipeline 1. The flow meter 7 is electrically connected to a regulating valve 8, so that the regulating valve 8 can be adjusted according to the set flow rate to control the 1,3-butadiene content on the transport pipeline 3.

[0031] In an exemplary embodiment, the flow meter 7 is also electrically connected to the detector 4. When the detector 4 detects a trend of 1,3-butadiene content decreasing to a first warning value, it sends a signal to the flow meter 7 to increase the flow rate, and adjusts the regulating valve 8 to increase the flow rate of the workpiece in the replenishment pipeline 1. Similarly, when the detector 4 detects a trend of 1,3-butadiene content increasing to a second warning value, it sends a signal to the flow meter 7 to decrease the flow rate, and adjusts the regulating valve 8 to decrease the flow rate of the workpiece in the replenishment pipeline 1, thereby maintaining a stable 1,3-butadiene content in the transport pipeline 3. The first warning value is less than the second warning value. In this embodiment, the detector 4 is equipped with cascade control logic. The main loop of the cascade control logic is used to analyze the content of 1,3-butadiene, and the secondary loop is used to measure the flow rate of the feed material by the flow meter 7. Based on the target value of 1,3-butadiene content in cracked C4, the opening of the regulating valve 8 is adjusted by the cascade control logic to control the flow rate of 1,3-butadiene from the pump 6, thereby stabilizing the 1,3-butadiene content and keeping the butadiene extraction and distillation system in a steady state. This avoids operational risks caused by changes in the composition of the raw materials and ensures the stable operation of the production unit.

[0032] In one exemplary embodiment, a one-way valve 2 is also provided on the replenishment pipeline 1, through which the work material in the replenishment pipeline 1 flows from the second end to the first end. By providing the one-way valve 2, it is possible to prevent the work material in the transport pipeline 3 from entering the replenishment pipeline 1, thus preventing 1,3-butadiene from reaching the designated location as required. In this embodiment, the one-way valve 2 is located near the first end of the replenishment pipeline 1, which better prevents the transport pipeline 3 from entering the replenishment pipeline 1.

[0033] In this embodiment, the discharge end of the transport pipeline 3 is connected to a raw material evaporator 5. After the raw material enters the raw material evaporator 5, it is heated and turns into a gaseous state before proceeding to subsequent processes. By setting up the raw material evaporator 5, the raw material can be further mixed to ensure that the 1,3-butadiene content in the raw material remains stable during subsequent processes. At the same time, since the raw material evaporator 5 can store a certain amount of raw material, it can prevent the subsequent production processes from stopping due to a lack of raw materials when the supply of 1,3-butadiene transported by the transport pipeline 3 is temporarily interrupted, thus providing a buffer for subsequent production.

[0034] In an exemplary embodiment, the replenishment line 1 is connected to the top of the heavy removal tower or the bottom of the light removal tower. In this embodiment, the 1,3-butadiene content in the feed material in the replenishment line 1 is greater than or equal to 99.5%. The top of the heavy removal tower or the bottom of the light removal tower can provide feed material with a 1,3-butadiene content greater than or equal to 99.5%. The high concentration of 1,3-butadiene flowing in the replenishment line 1 facilitates the adjustment of the 1,3-butadiene content on the transport line 3.

[0035] In an exemplary embodiment, a pump 6 is provided near the second end of the replenishment pipeline 1. The pump 6 provides energy to the working material flowing in the replenishment pipeline 1 to overcome the flow resistance of the working material in the replenishment pipeline 1, and delivers the working material to the transport pipeline 3 via the pump 6 according to process requirements.

[0036] In an exemplary embodiment, the detector 4 is a gas chromatograph. Gas chromatographs have high resolution, meaning they can effectively separate mixtures with extremely complex compositions and very similar physicochemical properties (such as homologues and isomers), and offer fast analysis speed, high sensitivity, and a high degree of automation.

[0037] In summary, by setting up a supplementary pipeline 1 connected to the transport pipeline 3, when the detector 4 detects a decreasing trend in the 1,3-butadiene content, a higher concentration of 1,3-butadiene can be introduced into the transport pipeline 3 through the supplementary pipeline 1 to increase the 1,3-butadiene content in the transport pipeline 3, ensuring the stable operation of subsequent processes and meeting the production goal of "safe, stable, long-term, full-capacity, and high-quality".

[0038] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A butadiene extraction device pipeline structure, characterized in that, include: A transport pipeline for transporting 1,3-butadiene, the transport pipeline having a receiving end and a discharging end, and a detector for detecting the content of 1,3-butadiene is installed on the transport pipeline; A supplementary pipeline is provided for supplying 1,3-butadiene at a concentration higher than that in the transport pipeline to the transport pipeline. The supplementary pipeline has a first end and a second end, the first end being connected to the transport pipeline and connected to the transport pipeline between the receiving end and the detector.

2. The butadiene extraction device pipeline structure according to claim 1, characterized in that: A regulating valve is installed on the replenishment pipeline, which is used to regulate the flow rate on the replenishment pipeline.

3. The butadiene extraction device pipeline structure according to claim 2, characterized in that: The supplementary pipeline is also equipped with a flow meter for measuring the flow rate on the supplementary pipeline, and the flow meter is electrically connected to the regulating valve.

4. The butadiene extraction device pipeline structure according to claim 3, characterized in that: The flow meter is also electrically connected to the detector.

5. The butadiene extraction apparatus pipeline structure according to any one of claims 1-4, characterized in that: The replenishment pipeline is also equipped with a one-way valve, through which the working material in the replenishment pipeline flows from the second end to the first end.

6. The butadiene extraction device pipeline structure according to claim 5, characterized in that: The one-way valve is positioned near the first end of the supplementary pipeline, relative to the second end.

7. The butadiene extraction apparatus pipeline structure according to any one of claims 1-4, characterized in that: The supplementary pipeline is connected to the top of the heavy removal tower or the bottom of the light removal tower.

8. The butadiene extraction apparatus pipeline structure according to any one of claims 1-4, characterized in that: A pump is installed on the supplementary pipeline near the second end.

9. The butadiene extraction apparatus pipeline structure according to any one of claims 1-4, characterized in that: The detector is a gas chromatograph.

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