Energy-saving butene-1 recovery device

Abstract

According to the butylene-1 recovery energy-saving device, in a reaction kettle, a raw material preheater comprises a raw material preheater cold end inlet for introducing an etherified C4 mixture, a raw material preheater cold end outlet for guiding out a preheated etherified C4 mixture, a raw material preheater hot end inlet and a raw material preheater hot end outlet; the deisobutanizer is provided with a tower top feed port which is connected with a cold end outlet of the raw material preheater and is used for introducing an etherified C4 mixture for rectification, a tower top outlet for guiding out gas obtained by rectification, a reflux inlet and a tower bottom discharge port for guiding out heavy components obtained by rectification; the deisobutanizer condenser comprises a gas inlet connected with a tower top outlet and a liquid outlet used for leading out gas and liquefying the gas into liquid, the deisobutanizer reboiler is connected with a tower bottom discharge port, and the butene-1 tower condenser comprises an outlet and an inlet connected with a hot end inlet of the raw material preheater; and a tower top outlet of the butene-1 tower is connected with a hot end inlet of the deisobutanizer reboiler so as to introduce heat into the deisobutanizer reboiler. The device is good in energy-saving effect.

Description

Technical Field

[0001] This utility model relates to the field of chemical separation technology, and in particular to an energy-saving device for butene-1 recovery. Background Technology

[0002] Butene-1 is a chemically reactive α-olefin with a wide range of applications. It is an important chemical raw material, used as a comonomer in the production of linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and polybutene-1 (PB-1). It can also be used to produce butadiene, isoprene, and various α-olefins with eight or more carbon atoms. This has promoted the vigorous development of the oil additives and high-end lubricant industries, providing new market opportunities for butene-1.

[0003] Currently, the main domestic technology for producing butene-1 is the mixed C4 separation method, with the remaining portions produced using butene isomerization and ethylene dimerization. The common practice in mixed C4 separation is to convert or separate butadiene through techniques such as butadiene extraction and selective hydrogenation. Then, isobutane and isobutene are separated or converted through a combination and optimization of techniques such as distillation and isobutene n-assembly (or etherification) or polyisobutene. Finally, 2-butene and n-butane, among other heavy components, are removed by extractive distillation or precision distillation to obtain the butene-1 product.

[0004] The main process of precision distillation is two-stage distillation. This process is simple and does not pollute the environment. However, due to the small difference in boiling points between light and heavy components, too many trays are needed to separate butene-1. Generally, upper and lower columns are used instead of a single column. In addition, the reflux ratio is too large, resulting in high energy consumption.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this utility model, and therefore may contain information that does not constitute prior art known to those skilled in the art. Utility Model Content

[0006] The purpose of this invention is to provide an energy-saving device for butene-1 recovery, which utilizes the waste heat of etherified selective hydrogenation of C4 butene-1 for energy-saving recovery. While meeting the butene-1 product specifications and yield requirements, the device increases economic efficiency, is simple to operate, and is easy to use.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] This utility model provides a butene-1 recovery and energy-saving device, which includes:

[0009] A raw material preheater includes a cold end inlet for introducing the post-etherified C4 mixture, a cold end outlet for discharging the preheated post-etherified C4 mixture, a hot end inlet for heat exchange, and a hot end outlet.

[0010] The isobutane removal column is provided with a top feed inlet connected to the cold end outlet of the raw material preheater to introduce the post-ether C4 mixture for distillation, a top outlet for discharging the gas obtained from distillation, a reflux port, and a bottom outlet for discharging the heavy components obtained from distillation.

[0011] A deisobutane removal tower condenser includes an inlet connected to the top outlet of the tower and a liquid outlet for discharging the gas into a liquid, the liquid outlet being connected to the reflux port to return the liquid to the deisobutane removal tower;

[0012] The isobutane removal tower reboiler is connected to the bottom outlet of the tower. The isobutane removal tower reboiler also includes a hot end inlet for introducing heat and a hot end outlet for the isobutane removal tower reboiler connected to the hot end inlet of the raw material preheater.

[0013] The butene-1 tower condenser includes an outlet and an inlet connected to the hot end inlet of the feed preheater;

[0014] Butene-1 tower, which includes,

[0015] The butene-1 column inlet is connected to the reboiler of the isobutane removal column and the bottom outlet of the column.

[0016] The top outlet of the butene-1 column is connected to the hot-end inlet of the reboiler of the isobutane removal column to introduce heat into the reboiler of the isobutane removal column.

[0017] The butene-1 column reflux port is connected to the outlet of the butene-1 column condenser, and

[0018] The tower internals are equipped with floating valve packing, and a double-layer gas-liquid distributor is installed at the feed inlet of the butene-1 tower.

[0019] The butene-1 recovery energy-saving device also includes a butene-1 tower reboiler connected to the butene-1 tower outlet.

[0020] In the aforementioned butene-1 recovery energy-saving device, the liquid outlet is connected to the outlet for discharging liquid.

[0021] In the aforementioned butene-1 recovery energy-saving device, the top outlet of the tower is connected to a fuel gas pipeline network.

[0022] In the aforementioned butene-1 recovery energy-saving device, the isobutane removal tower is equipped with an inlet weir, an outlet weir, and a downcomer.

[0023] In the aforementioned butene-1 recovery energy-saving device, the isobutane removal tower has a bottom structure.

[0024] In the above technical solution, the butene-1 recovery and energy-saving device provided by this utility model has the following beneficial effects: the butene-1 recovery and energy-saving device makes full use of the waste heat of the gas phase at the top of the butene-1 tower, which has obvious energy-saving characteristics. The gas phase of the butene-1 tower provides heat for the bottom of the deisobutane tower and the feed of the deisobutane tower, which reduces the consumption of steam and circulating water. The operation is simple and improves the economic efficiency of the device. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings.

[0026] Figure 1 This is a schematic diagram of the butene-1 recovery and energy-saving device of this utility model. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0028] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0029] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0030] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0032] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0033] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0034] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings.

[0035] like Figure 1 As shown, in one embodiment, the butene-1 recovery energy-saving device of this utility model includes,

[0036] The raw material preheater 5 includes a raw material preheater cold end inlet for introducing the post-etherified C4 mixture, a raw material preheater cold end outlet for discharging the preheated post-etherified C4 mixture, a raw material preheater hot end inlet for heat exchange, and a raw material preheater hot end outlet.

[0037] The isobutane removal column 1 is provided with a top feed inlet connected to the cold end outlet of the raw material preheater to introduce the post-ether C4 mixture for distillation, a top outlet for discharging the gas obtained from distillation, a reflux port, and a bottom outlet for discharging the heavy components obtained from distillation.

[0038] The isobutane removal tower condenser 3 includes an inlet connected to the top outlet of the tower and a liquid outlet for discharging the gas into a liquid, the liquid outlet being connected to the reflux port to return the liquid to the isobutane removal tower;

[0039] The isobutane removal tower reboiler 4 is connected to the bottom outlet of the tower. The isobutane removal tower reboiler also includes a hot end inlet for introducing heat and a hot end outlet for the isobutane removal tower reboiler connected to the hot end inlet of the raw material preheater.

[0040] The butene-1 tower condenser 6 includes an outlet and an inlet connected to the hot end inlet of the raw material preheater;

[0041] Butene-1 tower 2, which includes,

[0042] The butene-1 column inlet is connected to the reboiler of the isobutane removal column and the bottom outlet of the column.

[0043] The top outlet of the butene-1 column is connected to the hot-end inlet of the reboiler of the isobutane removal column to introduce heat into the reboiler of the isobutane removal column.

[0044] The butene-1 column reflux port is connected to the outlet of the butene-1 column condenser, and

[0045] The tower internals are equipped with floating valve packing, and a double-layer gas-liquid distributor is installed at the feed inlet of the butene-1 tower.

[0046] In a preferred embodiment of the butene-1 recovery energy-saving device, a butene-1 tower reboiler 7 connected to the butene-1 tower outlet is further included.

[0047] In a preferred embodiment of the butene-1 recovery energy-saving device, the liquid outlet is connected to the outlet for discharging liquid.

[0048] In a preferred embodiment of the butene-1 recovery energy-saving device, the top outlet of the tower is connected to a fuel gas pipeline network.

[0049] In a preferred embodiment of the butene-1 recovery energy-saving device, the isobutane removal tower is provided with an inlet weir, an outlet weir, and a downcomer.

[0050] In a preferred embodiment of the butene-1 recovery energy-saving device, the isobutane removal tower has a bottom structure.

[0051] In one embodiment, the butene-1 recovery energy-saving device includes a butane removal tower 1, a butene-1 tower 2, a butane removal tower top condenser 3, a butane removal tower reboiler 4, a feed preheater 5, a butene-1 tower condenser 6, and a butene-1 tower reboiler 7; a C4 hydrogenation reactor is selectively connected to the cold end inlet of the feed preheater after etherification; the cold end outlet of the feed preheater is connected to the top feed inlet of the butane removal tower; the top outlet of the butane removal tower is connected to the gas inlet of the butane removal tower condenser; and the liquid outlet of the butane removal tower condenser is connected to... The reflux port and discharge port of the isobutane removal tower are connected; the bottom discharge port of the isobutane removal tower is connected to the isobutane removal reboiler and the feed port of the butene-1 tower; the top outlet of the butene-1 tower is connected to the hot end inlet of the isobutane removal tower reboiler; the hot end outlet of the isobutane removal tower reboiler is connected to the hot end inlet of the raw material preheater; the hot end outlet of the raw material preheater is connected to the top condenser of the butene-1 tower; and the outlet of the butene-1 tower condenser is connected to the reflux port and discharge port of the butene-1 tower.

[0052] This invention solves the problem of excessive number of trays and high energy consumption in the butene-1 separation column due to the small boiling point difference between light and heavy components, resulting in an excessively large reflux ratio. By utilizing the overhead vapor phase of the butene-1 column to heat the isobutane removal column and the feed preheater, the heat of the overhead vapor phase of the butene-1 column is fully and rationally utilized, saving approximately 44% of steam consumption, effectively reducing energy consumption, and increasing the economic benefits of the equipment.

[0053] In the butene-1 recovery energy-saving unit, the C4 mixture after etherification includes n-butane, isobutane, trans-2-butene, butene-1, isobutene, cis-2-butene, and small amounts of C2 and C3 components. After heating the top material of the butene-1 tower, it enters the isobutane removal tower for rectification. The light components containing C2, C3, and isobutane are removed from the top of the isobutane removal tower and then enter the fuel gas pipeline. The heavy components from the bottom of the isobutane removal tower enter the butene-1 tower. The top gas phase of the butene-1 tower is heated by the bottom of the isobutane removal tower and used to preheat the feed. After being cooled by a condenser, part of the preheated material is refluxed back to the tower, and part is collected as the butene-1 product. The bottom material is rich in 2-butene and n-butane and is sent to the alkylation unit.

[0054] like Figure 1In the butene-1 recovery energy-saving device shown, the selected hydrogenated C4 feedstock after etherification enters the feedstock preheater 5 and the isobutane removal tower 1. After being heated by the top material of the butene-1 tower 2, it enters the isobutane removal tower 1 for distillation. The light components containing C2, C3 and isobutane are condensed and refluxed through the isobutane removal tower condenser 3, and part of them enter the fuel gas pipeline.

[0055] The heavy components from the bottom of the isobutane removal tower 1 enter the butene-1 tower 2. The vapor phase from the top of the butene-1 tower 2 enters the reboiler 4 of the isobutane removal tower to heat the bottom of the isobutane removal tower, and then enters the feed preheater 5 to preheat the feed. After being preheated, the material is cooled by the butene-1 tower condenser 6, with part of it being refluxed back to the tower and part being collected as the butene-1 product. Part of the bottom material of the butene-1 tower 2 is heated by the butene-1 tower reboiler 7 and returned to the butene-1 tower 2, while part of the bottom material is sent to the alkylation unit.

[0056] Examples 1-5

[0057] The butene-1 was recovered using the above process. The feed composition of the post-etherification C4 mixture in each embodiment is shown in Table 1 below:

[0058] Table 1. Feed composition of post-etherified C4 mixture

[0059]

[0060] The analysis results of butene-1 product after separation by the method of this invention are shown in Table 2 below:

[0061] Table 2. Product Analysis Data for Butene-1

[0062]

[0063] The separated butene-1 product has high purity, and the purity and impurities of butene-1 meet the superior grade indicators of the corresponding industry standards.

[0064] Comparative Example 1

[0065] This comparative example uses a conventional process of first removing light and then heavy components, adopts the same mixed product composition and purity requirements as in Example 1, and has a total raw material volume of 13.91 t / h and a temperature of 40°C.

[0066] The conventional light component removal followed by heavy component removal process involves the C4 mixture after etherification entering the top of the light component removal column, where it undergoes distillation to remove light components such as C2, C3, and isobutane. Then, it enters the heavy component removal column, where it undergoes distillation to remove heavy components such as n-butane, cis-2-butene, and trans-2-butene, ultimately yielding butene-1 product with a purity of 99.3%. All equipment requiring heating is heated using steam, and all equipment requiring cooling is cooled using condensate.

[0067] Table 3. Comparison of energy consumption for distillation in Example 1 and Comparative Example 1

[0068]

[0069] As can be seen from Table 3, from a thermodynamic perspective, the butene-1 recovery energy-saving device of this invention has significant energy-saving characteristics when processing a post-etherified C4 mixture containing n-butane, isobutane, trans-2-butene, butene-1, isobutene, cis-2-butene, and a small amount of C2 and C3 components. Compared with the conventional process of first removing light components and then removing heavy components, it saves 44% of energy consumption, demonstrating significant energy-saving characteristics.

[0070] Finally, it should be noted that the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0071] The foregoing description only illustrates certain exemplary embodiments of the present invention. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A butene-1 recovery energy saving device characterized by, It comprises, a feed preheater comprising a feed preheater cold end inlet for introducing the etherate C4 mixture, a feed preheater cold end outlet for discharging the preheated etherate C4 mixture, a feed preheater hot end inlet and a feed preheater hot end outlet for heat exchange; a de-isobutanizer column provided with a column top feed inlet connected to the feed preheater cold end outlet for introducing the etherate C4 mixture for rectification, a column top outlet for discharging the rectified gas, a reflux inlet and a column bottom discharge outlet for discharging the rectified heavy components; a de-isobutanizer column condenser comprising a gas inlet connected to the column top outlet and a liquid outlet for discharging the gas liquefied into liquid, the liquid outlet being connected to the reflux inlet for refluxing the liquid into the de-isobutanizer column; a de-isobutanizer column reboiler connected to the column bottom discharge outlet, the de-isobutanizer column reboiler further comprising a de-isobutanizer column reboiler hot end inlet for introducing heat and a de-isobutanizer column reboiler hot end outlet connected to the feed preheater hot end inlet; a butene-1 column condenser comprising an outlet and an inlet connected to the feed preheater hot end inlet; a butene-1 column comprising, a butene-1 column feed inlet connected to the de-isobutanizer column reboiler and the column bottom discharge outlet, a butene-1 column top outlet connected to the de-isobutanizer column reboiler hot end inlet for introducing heat into the de-isobutanizer column reboiler, a butene-1 column reflux inlet connected to the outlet of the butene-1 column condenser, and a butene-1 column discharge outlet, a column internal provided with float valve packing, a double-layer gas-liquid distributor being arranged at the butene-1 column feed inlet.

2. The butene-1 recovery energy saving device according to claim 1, characterized in that, a butene-1 column reboiler connected to the butene-1 column discharge outlet is further included.

3. The butene-1 recovery energy saving device according to claim 1, characterized in that, the liquid outlet is connected to a discharge outlet for discharging the liquid.

4. The butene-1 recovery energy saving device according to claim 1, characterized in that, the column top outlet is connected to a fuel gas pipe network.

5. The butene-1 recovery energy saving device according to claim 1, characterized in that, the de-isobutanizer column is provided with an inlet weir, an outlet weir and a downcomer.

6. The butene-1 recovery energy saving device according to claim 1, characterized in that, the de-isobutanizer column has a column kettle structure.

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