A device for recovering heat from the overhead gas of a cyclohexane heavy-removal column in SBS production

Abstract

The utility model relates to a chemical production device technical field, especially in SBS production in cyclohexane removes heavy tower top gas phase heat recovery device, it has first gas phase condenser its shell pass import through first pipeline intercommunication cyclohexane removes heavy tower top, its shell pass export through second pipeline intercommunication cooler, first gas phase condenser pipe pass is used for through the need preheating to be recycled cyclohexane solvent, it has second gas phase condenser its shell pass import connection on first pipeline, its shell pass export connection on second pipeline, butadiene removes heavy tower reboiler and supply hot water to it's hot water tank, butadiene removes heavy tower reboiler backwater mouth connection second gas phase condenser's pipe pass import, second gas phase condenser's pipe pass export intercommunication hot water tank, the utility model discloses in tower top gas phase pipeline adds second gas phase condenser, with butadiene removes heavy tower reboiler backwater and carries out heat exchange, reduces hot water tank heating use steam consumption, reduces the amount of use of cooler condensation circulating water simultaneously, reduces energy consumption.

Description

Technical Field

[0001] This utility model relates to the field of chemical production equipment technology, and in particular to a device for recovering the vapor phase heat from the top of the cyclohexane deweighting tower in SBS production. Background Technology

[0002] Styrene-butadiene-styrene block copolymer (SBS) is an important thermoplastic elastomer widely used in the production of sole materials for leather shoes, sneakers, and athletic shoes, as well as in asphalt modification. The industrial production of SBS involves polymerization of butadiene and styrene as monomers, cyclohexane as a solvent, and the addition of polymerization initiators and reaction activators.

[0003] SBS production units include recovery, polymerization, condensation, and post-processing units. The recovery unit uses equipment such as distillation columns to dehydrate and remove heavy phases from the wet solvent produced in the condensation unit, removing impurities such as moisture and polymerization inhibitors, and then provides qualified cyclohexane solvent for the polymerization unit. During the recovery process, vapor-phase heat is generated at the top of the heavy phase removal column. To utilize this heat, the recovered cyclohexane feed undergoes vapor-phase heat exchange via a vapor-phase condenser at the top of the heavy phase removal column, achieving a preheating effect on the solvent feed. However, under full-load operation, some existing production units, although the vapor-phase heat at the top of the heavy phase removal column undergoes heat exchange with the cyclohexane solvent feed, still have some unutilized heat, requiring condensation using circulating water in a cooler before flowing to the reflux tank, resulting in energy waste. Utility Model Content

[0004] The purpose of this invention is to provide a device for recovering the vapor phase heat from the top of the cyclohexane deweighting tower in SBS production, thereby solving the problems existing in the prior art. To achieve the above objective, this invention provides the following technical solution:

[0005] This utility model provides a device for recovering the vapor phase heat from the top of the cyclohexane deweighting tower in SBS production, comprising:

[0006] The system includes a cyclohexane deweighting tower, a first gas-phase condenser, and a cooler; the shell-side inlet of the first gas-phase condenser is connected to the top of the cyclohexane deweighting tower via a first pipeline, and its shell-side outlet is connected to the cooler via a second pipeline; the tube side of the first gas-phase condenser is used for passing preheated cyclohexane solvent to be recovered, and also includes:

[0007] The second gas-phase condenser has its shell-side inlet connected to the first pipeline and its shell-side outlet connected to the second pipeline.

[0008] The butadiene deweighting tower reboiler and the hot water tank that supplies hot water thereto, wherein the return water port of the butadiene deweighting tower reboiler is connected to the tube-side inlet of the second gas phase condenser, and the tube-side outlet of the second gas phase condenser is connected to the hot water tank.

[0009] As a further technical solution, a reflux tank is also included. The cooler is connected to the reflux tank via a third pipeline. The reflux tank is connected to the reflux pump via a fourth pipeline. The reflux pump is connected to the cyclohexane deweighting tower via a fifth pipeline.

[0010] As a further technical solution, a sixth pipeline is provided from the fifth pipeline to connect to the reflux tank.

[0011] As a further technical solution, a temperature instrument is provided on the first pipeline, and the connection point between the second vapor phase condenser and the first pipeline is located behind the temperature instrument; a valve is provided on the pipeline between the shell-side inlet of the second vapor phase condenser and the first pipeline, and a valve is provided on the pipeline between the shell-side outlet of the second vapor phase condenser and the second pipeline.

[0012] As a further technical solution, the valve is a gate valve.

[0013] As a further technical solution, the return water inlet of the butadiene deweighting tower reboiler is connected to the hot water tank.

[0014] As a further technical solution, both the first gas phase condenser and the second gas phase condenser are shell-and-tube condensers.

[0015] As a further technical solution, the cooler is a shell-and-tube cooler.

[0016] The beneficial effects of this utility model are as follows:

[0017] This invention adds a second gas phase condenser to the gas phase pipeline at the top of the cyclohexane deweighting tower. The gas phase exchanges heat with the hot water return from the reboiler of the butadiene deweighting tower via the shell side. The return water returns to the hot water tank, increasing the temperature of the hot water tank and reducing the amount of steam used for heating the hot water tank. At the same time, through heat exchange and condensation in the first and second gas phase condensers, the heat of the gas phase is fully recovered and utilized. The condensed liquid phase enters the cooler, reducing the amount of circulating condensate water used in the cooler, and thus reducing energy consumption to a certain extent. Attached Figure Description

[0018] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute a limitation thereof. It should also be understood that these drawings are shown for simplicity and clarity and are not necessarily drawn to scale. This utility model will now be described and explained with additional features and details using the drawings, wherein:

[0019] Figure 1 A simplified schematic diagram of the waste heat recovery device at the top of the SBS deweighting tower in an embodiment of this utility model is shown.

[0020] In the diagram: 1. Cyclohexane deweighting tower; 2. Cyclohexane deweighting tower reboiler; 3. First vapor phase condenser; 4. Cooler; 5. Reflux tank; 6. Reflux pump; 7. Second vapor phase condenser; 8. Hot water tank; 9. Butadiene deweighting tower reboiler; 10. Butadiene deweighting tower. Detailed Implementation

[0021] The technical solutions in the typical embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0022] like Figure 1 As shown, this embodiment provides a vapor phase heat recovery device at the top of the cyclohexane deweighting tower in SBS production. A portion of the existing device includes a cyclohexane deweighting tower 1, a first vapor phase condenser 3, a cooler 4, a reflux tank 5, and a reflux pump 6.

[0023] The cyclohexane deweighting column 1 is a highly efficient distillation column used to remove impurities from the cyclohexane solvent. The gas phase discharged from the top of the column contains a large amount of heat. To recover this heat, a first gas phase condenser 3 is installed at the top of the cyclohexane deweighting column 1. In this embodiment, the first gas phase condenser 3 is a shell-and-tube condenser.

[0024] Specifically, the shell-side inlet of the first gas-phase condenser 3 is connected to the top of the cyclohexane deweighting tower 1 via a first pipeline (gas phase pipeline), and its shell-side outlet is connected to the cooler 4 via a second pipeline. The tube side of the first gas-phase condenser 3 is used to pass the cyclohexane solvent to be recovered, which needs to be preheated. The heat released in the gas phase is used to preheat the cyclohexane solvent in the tube side, realizing heat recovery and utilization. It should be noted that cyclohexane, as a solvent in the reaction, has low loss during the reaction process. Therefore, cyclohexane can be recycled in SBS production, but it needs to be removed by the cyclohexane deweighting tower 1 to remove impurities, and it needs to be preheated by the first gas-phase condenser before entering the cyclohexane deweighting tower 1.

[0025] The cyclohexane deweighting tower 1 is equipped with a cyclohexane deweighting tower reboiler 2, the purpose of which is to heat the bottom of the cyclohexane deweighting tower 1, so that the cyclohexane at the bottom of the tower boils and is purified in the cyclohexane deweighting tower 1, and qualified cyclohexane in a gaseous state with heat is obtained at the top of the tower.

[0026] Cooler 4 is a shell-and-tube cooler used to further cool the condensed material after passing through the first gas phase condenser 3. Under full-load operation, some existing production units, although the gas phase energy at the top of the deweighting tower is exchanged for heat through the cyclohexane solvent feed, some energy is still not fully utilized, and the condensed material does not meet the reflux requirements, so it still needs to be condensed in the cooler using circulating water. The cooled material flows to the reflux tank 5, resulting in energy waste.

[0027] To address the aforementioned issues, the recovery unit also includes a second vapor-phase condenser 7, a hot water tank 8, and a butadiene deweighting tower reboiler 9. The butadiene deweighting tower reboiler 9 is integrated with the butadiene deweighting tower 10. The butadiene deweighting tower 10, the cyclohexane deweighting tower 1, the reboiler, and the hot water tank 8 all belong to the recovery unit of the SBS production plant, but are located in different systems. The hot water tank 8 supplies hot water to the butadiene deweighting tower reboiler; currently, the heat source for the hot water tank 8 is steam.

[0028] The second vapor-phase condenser 7 is also a shell-and-tube condenser, with its shell-side inlet connected to the first pipeline and its shell-side outlet connected to the second pipeline. The return water port of the butadiene de-burden tower reboiler 9 is connected to the tube-side inlet of the second vapor-phase condenser 7, and the tube-side outlet of the second vapor-phase condenser 7 is connected to the hot water tank 8. The heat released from the vapor phase preheats the hot water in the tube side, providing a heat source for the hot water tank 8 other than steam. This means that the hot water tank 8 has two heat sources.

[0029] In this embodiment, a second gas phase condenser 7 is added to the gas phase pipeline at the top of the cyclohexane deweighting tower 1. The gas phase exchanges heat with the hot water return from the reboiler 9 of the butadiene deweighting tower 10 through the shell side. The return water returns to the hot water tank 8, increasing the temperature of the hot water tank 8 and reducing the amount of steam used for heating the hot water tank 8. At the same time, through heat exchange and condensation between the first gas phase condenser 3 and the second gas phase condenser 7, the heat of the gas phase is fully recovered and utilized. The condensed liquid phase enters the cooler 4, reducing the amount of condensate circulating water used in the cooler 4 and reducing energy consumption to a certain extent.

[0030] The existing pipelines between the butadiene deweighting tower reboiler 9 and the hot water tank 8 are not removed. The return water inlet of the butadiene deweighting tower reboiler 9 is connected to the hot water tank 8, and the hot water tank 8 is then connected to the inlet of the butadiene deweighting tower reboiler 9. Valves are only installed at appropriate adjustment positions. In special cases, such as when there is no gas phase in the second gas phase condenser 7, the return water from the butadiene deweighting tower reboiler 9 does not pass through the second gas phase condenser 7 but flows directly into the hot water tank. This avoids the influence of the cyclohexane system on the butadiene system.

[0031] In this embodiment, the cooler 4 is connected to the reflux tank 5 via a third pipeline, the reflux tank 5 is connected to the reflux pump 6 via a fourth pipeline, and the reflux pump 6 is connected to the cyclohexane de-heavy column 1 via a fifth pipeline. The reflux pump 6 refluxes a portion of the liquid cyclohexane in the reflux tank 5 back to the cyclohexane de-heavy column 1, realizing mass transfer between gas and liquid and achieving continuous distillation.

[0032] Because the reflux pump 6 has a minimum flow rate, and to ensure that the reflux pump 6 does not stop, a sixth pipeline is connected to the reflux tank 5 from the fifth pipeline to achieve self-circulation between the reflux pump 6 and the reflux tank 5.

[0033] A temperature gauge (TG) is installed on the first pipeline. The connection point between the second vapor phase condenser 7 and the first pipeline is located behind the temperature gauge. A valve is installed on the pipeline between the shell-side inlet of the second vapor phase condenser 7 and the first pipeline, and a valve is installed on the pipeline between its shell-side outlet and the second pipeline. In this embodiment, the valves are gate valves, and the temperature gauge (TG) is used to monitor the temperature at the top of the cyclohexane deweighting tower 1.

[0034] During the device design process, the proportion of gas phase entering the first gas phase condenser 3 and the second gas phase condenser 7 is determined through heat calculation. Then, the proportion is adjusted by regulating the valve opening or by designing the pipeline diameter ratio (the ratio of the pipeline diameter entering the first gas phase condenser 3 to the pipeline diameter entering the second gas phase condenser 7).

[0035] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A vapor phase heat recovery device for the top of a cyclohexane deweighting tower in SBS production, comprising a cyclohexane deweighting tower, a first vapor phase condenser, and a cooler; the shell-side inlet of the first vapor phase condenser is connected to the top of the cyclohexane deweighting tower via a first pipeline, and the shell-side outlet is connected to the cooler via a second pipeline. The first gas-phase condenser tube side is used for passing preheated cyclohexane solvent to be recovered, characterized in that it further includes: The second gas-phase condenser has its shell-side inlet connected to the first pipeline and its shell-side outlet connected to the second pipeline. The butadiene deweighting tower reboiler and the hot water tank that supplies hot water thereto, wherein the return water port of the butadiene deweighting tower reboiler is connected to the tube-side inlet of the second gas phase condenser, and the tube-side outlet of the second gas phase condenser is connected to the hot water tank.

2. The cyclohexane deweighting tower top vapor phase heat recovery device in SBS production as described in claim 1, characterized in that, It also includes a reflux tank, the cooler is connected to the reflux tank via a third pipeline, the reflux tank is connected to the reflux pump via a fourth pipeline, and the reflux pump is connected to the cyclohexane deweighting tower via a fifth pipeline.

3. The cyclohexane deweighting tower top vapor phase heat recovery device in SBS production as described in claim 2, characterized in that, A sixth pipeline is connected to the reflux tank from the fifth pipeline.

4. The cyclohexane deweighting tower top vapor phase heat recovery device in SBS production as described in claim 1, characterized in that, A temperature instrument is installed on the first pipeline, and the connection point between the second vapor phase condenser and the first pipeline is located behind the temperature instrument; a valve is installed on the pipeline between the shell-side inlet of the second vapor phase condenser and the first pipeline, and a valve is installed on the pipeline between the shell-side outlet of the second vapor phase condenser and the second pipeline.

5. The cyclohexane deweighting tower top vapor phase heat recovery device in SBS production as described in claim 4, characterized in that, The valve is a gate valve.

6. The cyclohexane deweighting tower top vapor phase heat recovery device in SBS production as described in claim 1, characterized in that, The return water inlet of the butadiene deweighting tower reboiler is connected to the hot water tank.

7. The cyclohexane deweighting tower top vapor phase heat recovery device in SBS production as described in claim 1, characterized in that, Both the first gas phase condenser and the second gas phase condenser are shell-and-tube condensers.

8. The cyclohexane deweighting tower top vapor phase heat recovery device in SBS production as described in claim 1, characterized in that, The cooler is a shell-and-tube cooler.

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