A cis-butadiene rubber recovery unit provided with a gas phase heat recovery system

Abstract

The utility model relates to a technical field of chemical production device, especially a butadiene rubber recovery unit with gas phase heat recovery system, including solvent system and butadiene system, the first gas phase condenser is additionally arranged at the top of n-hexane heavy removal column, the shell side import is connected with the air cooler export through the second pipeline, and the shell side export is connected with the cooler import through the third pipeline; the tube side import is connected with the solvent loading valve group, and the tube side export is connected with the tube side import of third gas phase condenser, and the tube side export of third gas phase condenser is connected with the n-hexane dehydration column feed inlet through the preheater; the shell side import of third gas phase condenser is connected with the top of n-hexane dehydration column, and the shell side export is connected with the n-hexane heavy removal column feed inlet; the two gas phase condensers of the utility model increase make full use of the gas phase heat of the top of n-hexane heavy removal column, and reduce the steam consumption of solvent system and butadiene system, and the purpose of energy saving and consumption reduction is achieved.

Description

Technical Field

[0001] This utility model relates to the field of chemical production equipment technology, and in particular to a butadiene rubber recovery unit equipped with a gas phase heat recovery system. Background Technology

[0002] Butadiene rubber is a structurally regular synthetic rubber polymerized from butadiene. A butadiene rubber production unit consists of modules such as a recovery unit, a polymerization unit, a coagulation unit, and a post-processing unit. The recovery unit includes a solvent system and a butadiene system. The solvent system comprises a hexane dehydration tower and a hexane deweighting tower. The hexane solvent is dehydrated in the hexane dehydration tower and then deweighted in the hexane deweighting tower to meet the polymerization solvent requirements. The butadiene system includes a butadiene dehydration tower and a butadiene deweighting tower. The butadiene deweighting tower allows the butadiene monomer to meet the polymerization requirements.

[0003] Under normal production conditions, (1) in the solvent system, n-hexane solvent needs to be preheated to the set temperature before entering the n-hexane dehydration tower. Specifically, the solvent system feed (around 40°C) exchanges heat with the gaseous material at the top of the dehydration tower via the top condenser, raising the feed temperature to around 60°C. It is then heated to 90°C by the feed preheater before entering the hexane dehydration tower. This requires a large amount of steam for the feed preheater. (2) Meanwhile, the heat source for the reboilers in the butadiene dehydration tower and butadiene de-weighting tower in the butadiene system is provided by the hot water in the hot water tank. After the hot water exchanges heat with the butadiene, the temperature of the hot water decreases and returns to the hot water tank for reheating and continued recycling. This part of the hot water also requires steam consumption through the process of heating-cooling-heating. (3) However, in the solvent system, the gaseous material at the top of the hexane dehydration tower needs to be cooled by the air cooler and circulating water. Sometimes, the solvent temperature is still high (above 40°C) after cooling. This part of the gaseous heat is not fully utilized, resulting in heat loss. Instead, it needs to be cooled by cooling water.

[0004] In summary, the heat in the butadiene rubber recovery unit was not effectively recovered and utilized, and a large amount of steam or cooling water was consumed in order to preheat the solvent or cool the gaseous material. Utility Model Content

[0005] The purpose of this invention is to provide a butadiene rubber recovery unit equipped with a gas phase heat recovery system to solve the problems existing in the prior art. To achieve the above objective, this invention provides the following technical solution:

[0006] This utility model provides a butadiene rubber recovery unit equipped with a gas phase heat recovery system, including a solvent system and a butadiene system. The solvent system includes a hexane deweighting tower, an air cooler, a cooler, a hexane dehydration tower, a third gas phase condenser, and a preheater. The inlet of the air cooler is connected to the top of the hexane deweighting tower via a first pipeline. The butadiene system includes a butadiene deweighting tower reboiler, a butadiene dehydration tower reboiler, and a hot water tank for supplying hot water to them. It also includes:

[0007] The first gas-phase condenser has its shell-side inlet connected to the outlet of the air cooler via a second pipeline, and its shell-side outlet connected to the inlet of the cooler via a third pipeline; its tube-side inlet is connected to the solvent feed valve group, and its tube-side outlet is connected to the tube-side inlet of the third gas-phase condenser; the tube-side outlet of the third gas-phase condenser is connected to the feed inlet of the n-hexane dehydration tower via the preheater; the shell-side inlet of the third gas-phase condenser is connected to the top of the n-hexane dehydration tower, and its shell-side outlet is connected to the feed inlet of the n-hexane deweighting tower.

[0008] As a further technical solution, it also includes:

[0009] The second gas-phase condenser has its shell-side inlet connected to the air cooler outlet via the second pipeline, and its shell-side outlet connected to the cooler inlet via the third pipeline; its tube-side inlet is connected to the reboiler return water inlet of the butadiene dehydration tower and the reboiler return water inlet of the butadiene dewatering tower, and its tube-side outlet is connected to the hot water tank.

[0010] As a further technical solution, valves are provided at the shell-side inlet and outlet, and the tube-side inlet and outlet of the first gas phase condenser, the second gas phase condenser, and the third gas phase condenser.

[0011] As a further technical solution, the valve is a gate valve.

[0012] As a further technical solution, the first gas phase condenser, the second gas phase condenser and the third gas phase condenser are all shell-and-tube condensers.

[0013] As a further technical solution, the cooler is a shell-and-tube cooler.

[0014] As a further technical solution, a reflux tank is also included, the inlet of which is connected to the outlet of the cooler, and the outlet of the reflux tank is connected to the n-hexane deweighting tower through a fourth pipeline, the fourth pipeline being equipped with a reflux pump.

[0015] The beneficial effects of this utility model are as follows:

[0016] This invention adds two vapor-phase condensers at the top of the hexane de-heavy tower. The hexane solvent feed exchanges heat with the first vapor-phase condenser and then continues to exchange heat and increase temperature in the third vapor-phase condenser at the top of the hexane dehydration tower. This further increases the solvent feed temperature, reducing the steam consumption of the solvent feed preheater. The second vapor-phase condenser exchanges heat with the hot water return from the reboilers of the butadiene de-heavy tower and the butadiene dehydration tower. The water after heat exchange returns to the hot water tank, thereby increasing the hot water temperature and reducing the steam consumption for heating the hot water tank. In summary, the two added vapor-phase condensers fully utilize the vapor-phase heat at the top of the hexane de-heavy tower and reduce the steam consumption of the solvent and butadiene systems, achieving the goal of energy saving and consumption reduction. Attached Figure Description

[0017] 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:

[0018] Figure 1 A schematic diagram of a butadiene rubber recovery unit with a gas phase heat recovery system is shown in an embodiment of this utility model.

[0019] In the diagram: 1. Hexane dehydration tower; 2. Air cooler; 3. Cooler; 4. Reflux tank; 5. Reflux pump; 6. First vapor phase condenser; 7. Second vapor phase condenser; 8. Butadiene dehydration tower reboiler; 9. Butadiene dehydration tower reboiler; 10. Hexane dehydration tower; 11. Butadiene dehydration tower; 12. Third vapor phase condenser; 13. Preheater; 14. Hot water tank; 15. Butadiene dehydration tower. Detailed Implementation

[0020] The technical solutions in the typical embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0021] like Figure 1As shown, this embodiment provides a butadiene rubber recovery unit equipped with a gas phase heat recovery system, including a solvent system and a butadiene system. The solvent system includes a hexane deweighting tower 1, an air cooler 2, a cooler 3, a hexane dehydration tower 10, a third gas phase condenser 12, and a preheater 13. The inlet of the air cooler 2 is connected to the top of the hexane deweighting tower 1 through a first pipeline (in existing devices, when no gas phase condenser is installed, the outlet of the air cooler 2 is connected to the cooler 3). The butadiene system includes a butadiene deweighting tower reboiler 9, a butadiene dehydration tower reboiler 8, and a hot water tank 14 that supplies hot water to them. The butadiene deweighting tower reboiler 9 is configured to the butadiene deweighting tower 15, and the butadiene dehydration tower reboiler 8 is configured to the butadiene dehydration tower 11.

[0022] It also includes a first gas phase condenser 6, whose shell-side inlet is connected to the outlet of air cooler 2 via a second pipeline, and whose shell-side outlet is connected to the inlet of cooler 3 via a third pipeline; its tube-side inlet is connected to the solvent feed valve group, and its tube-side outlet is connected to the tube-side inlet of the third gas phase condenser 12; the tube-side outlet of the third gas phase condenser 12 is connected to the feed port of n-hexane dehydration tower 10 via preheater 13; the shell-side inlet of the third gas phase condenser 12 is connected to the top of n-hexane dehydration tower 10, and its shell-side outlet is connected to the feed port of n-hexane deweighting tower 1.

[0023] It also includes a second gas phase condenser 7, whose shell-side inlet is connected to the outlet of air cooler 2 via a second pipeline, and whose shell-side outlet is connected to the inlet of cooler 3 via a third pipeline; its tube-side inlet is connected to the return water port of reboiler 9 of butadiene dehydration tower 11 and the return water port of reboiler 8 of butadiene dehydration tower 11, and its tube-side outlet is connected to hot water tank 14.

[0024] In this embodiment, two vapor-phase condensers are added to the top of the hexane de-heavy tower. The hexane solvent feed exchanges heat with the first vapor-phase condenser 6 and then continues to exchange heat and increase temperature through the third vapor-phase condenser 12 at the top of the hexane dehydration tower 10. This further increases the solvent feed temperature, thereby reducing the steam consumption of the solvent feed preheater 13. The second vapor-phase condenser 7 is used to exchange heat with the hot water return from the butadiene de-heavy tower reboiler 9 and the butadiene dehydration tower reboiler 8. The water after heat exchange returns to the hot water tank 14, thereby increasing the hot water temperature and reducing the steam consumption of the hot water tank 14. In summary, the two added vapor-phase condensers fully utilize the vapor-phase heat at the top of the hexane de-heavy tower 1 and reduce the steam consumption of the solvent system and the butadiene system, achieving the goal of energy saving and consumption reduction.

[0025] Taking the actual production of butadiene rubber in a certain enterprise as an example, the feed rate of the butadiene system is 19-20 cubic meters per hour. The reboiler 8 of the butadiene dehydration tower and the reboiler 9 of the butadiene deweighting tower require a large amount of hot water for heating. The source of hot water is the condensate heated by the reboiler steam of each tower in the solvent system. During normal production, the temperature of the hot water tank 14 is maintained at about 65°C. After the hot water exchanges heat with the reboiler 8 and the reboiler 9 of the butadiene dehydration tower (the water temperature after heat exchange is about 50°C), it returns to the hot water tank 14 after passing through the second vapor phase condenser 7 heat exchanger. If the temperature does not meet 65°C, the hot water tank 14 needs to be supplemented with some steam to maintain its temperature at about 65°C. The solvent system feed rate is about 90 cubic meters per hour. The feed (40°C) to the n-hexane dehydration tower 10 exchanges heat with the first gas phase condenser 6 added at the top of the n-hexane de-heavy tower 1 (80°C) to raise the solvent feed temperature to about 60°C. Then, it exchanges heat with the third gas phase condenser 12 at the top of the dehydration tower (98°C) to continue raising the temperature to about 75°C. Finally, it is heated to 90°C by the feed preheater 13 to reach the feed temperature before entering the n-hexane dehydration tower 10.

[0026] It should be noted that the number of air coolers 2, and the specifications of the first gas-phase condenser 6 and the second gas-phase condenser 7, must be determined based on heat calculations. For example, in this embodiment, the original device was equipped with four air coolers 2, but after heat calculations, only two air coolers 2 may be needed, in which case two of them can be deactivated. During the design process, after heat calculations, the appropriate number of air coolers 2, the specifications of the first gas-phase condenser 6 and the second gas-phase condenser 7 are selected, and the gas flow rates through the first gas-phase condenser 6 and the second gas-phase condenser 7 are calculated respectively to meet the design objectives and energy-saving requirements.

[0027] This embodiment also includes a reflux tank 4, the inlet of which is connected to the outlet of the cooler 3, and the outlet of the reflux tank 4 is connected to the n-hexane deweighting tower 1 through a fourth pipeline, on which a reflux pump 5 is installed.

[0028] In this embodiment, valves are provided at the shell-side inlet and outlet, and the tube-side inlet and outlet of the first vapor phase condenser 6, the second vapor phase condenser 7, and the third vapor phase condenser 12. Furthermore, all valves in this embodiment are gate valves.

[0029] In this embodiment, the first gas phase condenser 6, the second gas phase condenser 7, and the third gas phase condenser 12 are all shell-and-tube condensers, and the cooler 3 is a tubular cooler.

[0030] 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 butadiene rubber recovery unit equipped with a gas-phase heat recovery system, comprising a solvent system and a butadiene system, wherein the solvent system includes a hexane deweighting tower, an air cooler, a cooler, a hexane dehydration tower, a third gas-phase condenser, and a preheater, the inlet of the air cooler being connected to the top of the hexane deweighting tower via a first pipeline, and the butadiene system including a butadiene deweighting tower reboiler, a butadiene dehydration tower reboiler, and a hot water tank for supplying hot water thereto, characterized in that, Also includes: The first gas-phase condenser has its shell-side inlet connected to the air cooler outlet via a second pipeline, and its shell-side outlet connected to the cooler inlet via a third pipeline. Its tube-side inlet is connected to the solvent feeding valve group, its tube-side outlet is connected to the tube-side inlet of the third gas phase condenser, and the tube-side outlet of the third gas phase condenser is connected to the feed port of the n-hexane dehydration tower via the preheater; the shell-side inlet of the third gas phase condenser is connected to the top of the n-hexane dehydration tower, and its shell-side outlet is connected to the feed port of the n-hexane deweighting tower.

2. The butadiene rubber recovery unit equipped with a gas phase heat recovery system as described in claim 1, characterized in that, Also includes: The second gas-phase condenser has its shell-side inlet connected to the air cooler outlet via the second pipeline, and its shell-side outlet connected to the cooler inlet via the third pipeline. Its inlet tube is connected to the return water outlet of the butadiene dehydration tower reboiler and the return water outlet of the butadiene dewatering tower reboiler, and its outlet tube is connected to the hot water tank.

3. A butadiene rubber recovery unit equipped with a gas phase heat recovery system as described in claim 2, characterized in that, The shell-side inlet and outlet, and tube-side inlet and outlet of the first gas phase condenser, the second gas phase condenser, and the third gas phase condenser are all equipped with valves.

4. A butadiene rubber recovery unit equipped with a gas phase heat recovery system as described in claim 3, characterized in that, The valve is a gate valve.

5. A butadiene rubber recovery unit equipped with a gas phase heat recovery system as described in claim 2, characterized in that, The first gas phase condenser, the second gas phase condenser, and the third gas phase condenser are all shell-and-tube condensers.

6. A butadiene rubber recovery unit equipped with a gas phase heat recovery system as described in claim 1, characterized in that, The cooler is a shell-and-tube cooler.

7. A butadiene rubber recovery unit equipped with a gas phase heat recovery system as described in claim 1, characterized in that, It also includes a reflux tank, the inlet of which is connected to the outlet of the cooler, and the outlet of the reflux tank is connected to the n-hexane deweighting tower via a fourth pipeline, on which a reflux pump is provided.

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