Reaction heat recovery system of urea device

Abstract

The utility model discloses a reaction heat recovery system of a urea device. The reaction heat recovery system comprises a high-pressure washer, a high-pressure temperature-adjusting water cooler, a first reboiler, a heating heat exchange station and a heat exchanger, a high-pressure temperature-adjusting water outlet of the high-pressure washer is divided into three paths, the first path is communicated with a thermal medium inlet of the heat exchanger through a pipeline, and a thermal medium outlet of the heat exchanger is communicated with an inlet of the water inlet mixing pipe through a pipeline; the second path is communicated with a temperature-adjusting water inlet of the high-pressure temperature-adjusting water cooler through a pipeline, and a temperature-adjusting water outlet of the high-pressure temperature-adjusting water cooler is communicated with an inlet of the water inlet mixing pipe through a pipeline; the third path is communicated with a heat source inlet of the first reboiler through a pipeline, and a heat source outlet of the first reboiler is communicated with an inlet of the water inlet mixing pipe through a pipeline. The device has the advantages that the heat of high-pressure temperature-adjusting water is effectively utilized to provide heat preheating for a heating system and methanol thermal regeneration, the consumption of steam and circulating cooling water is reduced, energy conservation and consumption reduction are realized, and the heating cost and the production cost of an enterprise are reduced.

Description

Technical fields:

[0001] This utility model relates to a heat recovery system, and more particularly to a urea plant reaction heat recovery system. Background technology:

[0002] The NH3 and CO2 separated from the top of the urea synthesis tower are condensed in a high-pressure scrubber. Ammonia and CO2 react to form ammonium carbamate solution, and the heat released is carried away by high-pressure temperature-regulating water on the shell side. The temperature-regulating water temperature is increased from 110°C to 130°C at a flow rate of 1000 m³ / h. 3 / h. The heated high-pressure temperature-regulating water enters the tube side of the high-pressure temperature-regulating water cooler and is cooled. The 110°C temperature-regulating water coming out of the high-pressure temperature-regulating water cooler returns to the shell side of the high-pressure scrubber as a cooling medium, carrying away the heat generated by the ammonium carbamate reaction.

[0003] During this process, the high-pressure temperature-regulating water is cooled from 130°C to 110°C through the high-pressure temperature-regulating water cooler, resulting in a significant waste of heat energy and thus affecting the overall energy consumption of the urea plant.

[0004] Therefore, it is urgent to find a medium that can raise its own temperature as a cooling medium for high-temperature water, so as to realize the comprehensive utilization of the thermal energy of high-temperature water. Utility Model Content:

[0005] In order to solve the above problems, the purpose of this utility model is to provide a urea plant reaction heat recovery system.

[0006] This utility model is implemented by the following technical solution:

[0007] A urea plant reaction heat recovery system includes a high-pressure scrubber, a high-pressure temperature-regulating water cooler, a first reboiler, a heating heat exchange station, and a heat exchanger.

[0008] The high-pressure washer has three outlets for its high-pressure temperature-regulating water. The first outlet is connected to the heat medium inlet of the heat exchanger via a pipeline, and the heat medium outlet of the heat exchanger is connected to the inlet of the inlet water mixing pipe via a pipeline. The second outlet is connected to the temperature-regulating water inlet of the high-pressure temperature-regulating water cooler via a pipeline, and the temperature-regulating water outlet of the high-pressure temperature-regulating water cooler is connected to the inlet of the inlet water mixing pipe via a pipeline. The third outlet is connected to the heat source inlet of the first reboiler via a pipeline, and the heat source outlet of the first reboiler is connected to the inlet of the inlet water mixing pipe via a pipeline. The outlet of the inlet water mixing pipe is connected to the high-pressure temperature-regulating water inlet of the high-pressure washer.

[0009] The outlet of the heating return water pipe #1 is connected to the cold medium inlet of the heat exchanger via a pipeline. The cold medium outlet of the heat exchanger is connected to the return water inlet of the heating heat exchange station via the heating return water pipe #2. The return water outlet of the heating heat exchange station is connected to the inlet of the heating supply water pipe via a pipeline.

[0010] Furthermore, it also includes a methanol regeneration tower and a second reboiler;

[0011] The bottom methanol outlet of the methanol regeneration tower is connected to the methanol inlet of the first reboiler via a pipeline, and the methanol outlet of the first reboiler is connected to the middle liquid inlet of the methanol regeneration tower via a pipeline.

[0012] The bottom liquid outlet of the methanol regeneration tower is connected to the methanol inlet of the second reboiler via a pipeline, and the methanol outlet of the second reboiler is connected to the central liquid inlet of the methanol regeneration tower via a pipeline.

[0013] Furthermore, the outlet end of the No. 1 heating return water pipe is connected to the inlet end of the No. 2 heating return water pipe via a connecting pipeline. A connecting valve is provided on the connecting pipeline, and a shut-off valve is provided at the cold medium inlet of the heat exchanger.

[0014] Furthermore, a first temperature sensor is provided at the high-pressure temperature-regulating water inlet of the high-pressure washer, a first regulating valve is provided at the cold medium inlet of the high-pressure temperature-regulating water cooler, and a fourth regulating valve is provided at the temperature-regulating water inlet of the high-pressure temperature-regulating water cooler.

[0015] Furthermore, a second temperature sensor is provided at the cold medium outlet of the heat exchanger, and a second regulating valve is provided on the pipeline connecting the high-pressure temperature-regulating water outlet of the high-pressure scrubber to the first reboiler.

[0016] Furthermore, a third temperature sensor is provided at the heat source outlet of the first reboiler, and a third regulating valve is provided on the pipeline connecting the high-pressure scrubber and the heat medium inlet of the heat exchanger.

[0017] Advantages of this utility model:

[0018] This invention can effectively utilize the heat of high-pressure temperature-regulating water to preheat the heating system and methanol thermal regeneration in winter and summer, so that the heat energy of the high-pressure temperature-regulating water in the urea plant can be effectively utilized, reducing the heat exchange of the circulating water system, reducing the consumption of steam and circulating cooling water, avoiding a large waste of heat, achieving energy saving and consumption reduction and optimal system operation, thereby reducing the heating cost and production cost of enterprises. Attached image description:

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the system connection in this embodiment.

[0021] In the diagram: 1. High-pressure scrubber; 2. High-pressure temperature-regulating water cooler; 3. First reboiler; 4. Methanol regeneration tower; 5. Second reboiler; 6. Heating heat exchange station; 7. Heat exchanger; 8. No. 1 heating return water pipe; 9. Connecting pipeline; 10. No. 2 heating return water pipe; 11. Connecting valve; 12. Shut-off valve; 13. First temperature sensor; 14. First regulating valve; 15. Second temperature sensor; 16. Second regulating valve; 17. Third temperature sensor; 18. Third regulating valve; 19. Inlet mixing pipe; 20. Fourth regulating valve. Detailed implementation method:

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Example 1:

[0024] like Figure 1 The urea plant reaction heat recovery system shown includes a high-pressure scrubber 1, a high-pressure temperature-regulating water cooler 2, a first reboiler 3, a heating heat exchange station 6, and a heat exchanger 7.

[0025] The high-pressure washer 1 has three outlets for its high-pressure temperature-regulating water. The first outlet is connected to the heat medium inlet of the heat exchanger 7 via a pipeline, and the heat medium outlet of the heat exchanger 7 is connected to the inlet of the inlet water mixing pipe 19 via a pipeline. The second outlet is connected to the temperature-regulating water inlet of the high-pressure temperature-regulating water cooler 2 via a pipeline, and the temperature-regulating water outlet of the high-pressure temperature-regulating water cooler 2 is connected to the inlet of the inlet water mixing pipe 19 via a pipeline. The third outlet is connected to the heat source inlet of the first reboiler 3 via a pipeline, and the heat source outlet of the first reboiler 3 is connected to the inlet of the inlet water mixing pipe 19 via a pipeline. The outlet of the inlet water mixing pipe 19 is connected to the high-pressure temperature-regulating water inlet of the high-pressure washer 1.

[0026] The outlet of heating return water pipe 8 (No. 1) is connected to the cold medium inlet of heat exchanger 7 via a pipeline. The cold medium outlet of heat exchanger 7 is connected to the return water inlet of heating heat exchange station 6 via heating return water pipe 10 (No. 2). The return water outlet of heating heat exchange station 6 is connected to the inlet of heating supply water pipe via a pipeline. The outlet of heating return water pipe 8 (No. 1) is also connected to the inlet of heating return water pipe 10 (No. 2) via connecting pipeline 9. A connecting valve 11 is installed on connecting pipeline 9, and a shut-off valve 12 is installed at the cold medium inlet of heat exchanger 7.

[0027] This embodiment also includes a methanol regeneration tower 4 and a second reboiler 5; the bottom methanol outlet of the methanol regeneration tower 4 is connected to the methanol inlet of the first reboiler 3 via a pipeline, and the methanol outlet of the first reboiler 3 is connected to the middle liquid inlet of the methanol regeneration tower 4 via a pipeline; the bottom liquid outlet of the methanol regeneration tower 4 is connected to the methanol inlet of the second reboiler 5 via a pipeline, and the methanol outlet of the second reboiler 5 is connected to the middle liquid inlet of the methanol regeneration tower 4 via a pipeline.

[0028] To achieve interlocking control, this embodiment also includes a first temperature sensor 13 at the high-pressure temperature-regulating water inlet of the high-pressure washer 1, a first regulating valve 14 at the cold medium inlet of the high-pressure temperature-regulating water cooler 2, and a fourth regulating valve 20 at the temperature-regulating water inlet of the high-pressure temperature-regulating water cooler 2. A second temperature sensor 15 is installed at the cold medium outlet of the heat exchanger 7, and a second regulating valve 16 is installed on the pipeline connecting the high-pressure temperature-regulating water outlet of the high-pressure washer 1 and the first reboiler 3. A third temperature sensor 17 is installed at the heat source outlet of the first reboiler 3, and a third regulating valve 18 is installed on the pipeline connecting the high-pressure washer 1 and the heat medium inlet of the heat exchanger 7.

[0029] Job Description:

[0030] After the heat is absorbed and released during the reaction within the shell side of the high-pressure scrubber 1, the temperature rises from 110℃ to 130℃, with a flow rate of 1000m³. 3 / h, the heated high-pressure temperature-regulating water is divided into three streams through the high-pressure temperature-regulating water outlet of the high-pressure scrubber 1 for heat recovery. The first stream of high-pressure temperature-regulating water enters the heat exchanger 7, where it acts as a heat medium to transfer heat to the heating return water, preheating it and reducing the steam consumption of the heating heat exchange station 6; at the same time, the temperature of the high-pressure temperature-regulating water itself decreases. After flowing out of the heat medium outlet of the heat exchanger 7, this portion of high-pressure temperature-regulating water mixes with the other two streams of cooled high-pressure temperature-regulating water in the inlet mixing pipe 19 before entering the high-pressure scrubber 1 again to absorb the heat of reaction.

[0031] The second path of high-pressure temperature-regulating water directly enters the high-pressure temperature-regulating water cooler 2. After being cooled by the cooler, the temperature decreases and the water returns to the inlet mixing pipe 19. This path is mainly used to regulate the temperature of the high-pressure temperature-regulating water returning to the high-pressure scrubber 1, ensuring that the temperature of the high-pressure temperature-regulating water entering the high-pressure scrubber 1 is appropriate and meets the process requirements.

[0032] The third stream of high-pressure temperature-regulating water enters the first reboiler 3, serving as a heat source to provide heat for the methanol regeneration process. In the first reboiler 3, the high-pressure temperature-regulating water transfers heat to the methanol liquid, causing it to evaporate and return to the methanol regeneration tower 4. This reduces the steam consumption of the second reboiler 5. After cooling, the high-pressure temperature-regulating water flows out through the heat source outlet of the first reboiler 3 and then enters the inlet mixing pipe 19.

[0033] Through the inlet mixing pipe 19, the three streams of high-pressure temperature-regulating water are mixed and returned to the high-pressure temperature-regulating water inlet of the high-pressure scrubber 1, completing one cycle. In this process, the heat of the high-pressure temperature-regulating water is effectively utilized, providing the heat required for preheating the heating system and methanol thermal regeneration, reducing the consumption of steam and circulating cooling water in the high-pressure temperature-regulating water cooler 2, and achieving the goals of energy saving, consumption reduction, and optimal system operation.

[0034] During the winter heating season, the connecting valve 11 is closed, and the shut-off valve 12 and the third regulating valve 18 are opened. This allows the heating return water in the No. 1 heating return water pipe 8 to exchange heat with the high-pressure temperature regulating water in the heat exchanger 7. The heating water then enters the heating heat exchange station 6 through the No. 2 heating return water pipe 10, where it is heated to the required temperature by low-pressure steam and then sent to each heating point through the heating supply water pipe. When the high-pressure temperature regulating water can no longer enter the heat exchanger 7 to exchange heat with the heating return water due to a malfunction of the heat exchanger 7 or the high-pressure scrubber 1, the connecting valve 11 is opened, and the shut-off valve 12 and the third regulating valve 18 are closed. This allows the heating return water in the No. 1 heating return water pipe 8 to directly enter the heating heat exchange station 6 through the connecting pipeline 9 and the No. 2 heating return water pipe 10, where it is directly heated.

[0035] When heating is not required in summer, the connecting valve 11, the shut-off valve 12, and the third regulating valve 18 are all closed, and the heating return water no longer enters the heat exchanger 7 and the heating heat exchange station 6.

[0036] In this embodiment, during the winter heating season, the heat from the high-pressure temperature-regulating water can be partially used for preheating the heating water and partially for preheating methanol, reducing the amount of circulating cooling water used in the high-pressure temperature-regulating water cooler 2. During winter, the temperature of the preheated heating return water in the heat exchanger 7 can be detected by the second temperature sensor 15. While ensuring the preheating requirements of the heating return water are met, the opening of the second regulating valve 16 can be adjusted to regulate the amount of high-pressure temperature-regulating water entering the methanol regeneration tower 4, ensuring that as much high-pressure temperature-regulating water as possible is used to preheat the methanol thermal regeneration tower while still meeting the heating water preheating needs. During non-heating seasons, all the high-pressure temperature-regulating water can be used for preheating the methanol thermal regeneration tower, reducing the steam consumption of the first reboiler 3 in the methanol thermal regeneration tower.

[0037] In this embodiment, the first regulating valve 14 and the fourth regulating valve 20 are initially closed. Only when the first temperature sensor 13 detects that the high-pressure temperature regulating water return temperature at the high-pressure temperature regulating water inlet of the high-pressure washer 1 is higher than the return water temperature requirement (110°C) will the first regulating valve 14 and the fourth regulating valve 20 be opened. The amount of circulating cooling water entering the high-pressure temperature regulating water cooler 2 can be adjusted by adjusting the opening degree of the first regulating valve 14, so as to ensure that the high-pressure temperature regulating water entering the high-pressure washer 1 is moderate and meets the process requirements.

[0038] This embodiment effectively utilizes the heat from high-pressure temperature-regulating water to preheat the heating system and methanol thermal regeneration during winter and summer, reducing steam consumption and circulating cooling water consumption, achieving energy saving and consumption reduction and optimal system operation, thereby reducing the enterprise's heating costs and production costs.

[0039] Calculations show that it can transfer 63,740,000 kJ of heat to heating water, saving 626.3 t / h of low-pressure steam consumption at the heating heat exchange station of the thermal power plant, a 43% reduction in steam consumption compared to the original level. Simultaneously, the high-pressure temperature-regulating water cooler 2E204 of the urea plant can be shut down during the winter heating season, reducing the consumption of circulating cooling water in the original high-pressure temperature-regulating water cooler 2 by 60%. The company is located in a high-altitude, cold region with long winters and extremely low temperatures. Based on a heating season of 212 days from October to April of the following year and a low-pressure steam price of 40.89 yuan / t, the annual benefit is approximately 5.4717 million yuan.

[0040] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A urea plant reaction heat recovery system, characterized in that, It includes a high-pressure scrubber, a high-pressure temperature-regulating water cooler, a first reboiler, a heating heat exchange station, and heat exchangers. The high-pressure washer has three outlets for its high-pressure temperature-regulating water. The first outlet is connected to the heat medium inlet of the heat exchanger via a pipeline, and the heat medium outlet of the heat exchanger is connected to the inlet of the inlet water mixing pipe via a pipeline. The second outlet is connected to the temperature-regulating water inlet of the high-pressure temperature-regulating water cooler via a pipeline, and the temperature-regulating water outlet of the high-pressure temperature-regulating water cooler is connected to the inlet of the inlet water mixing pipe via a pipeline. The third outlet is connected to the heat source inlet of the first reboiler via a pipeline, and the heat source outlet of the first reboiler is connected to the inlet of the inlet water mixing pipe via a pipeline. The outlet of the inlet water mixing pipe is connected to the high-pressure temperature-regulating water inlet of the high-pressure washer. The outlet of the heating return water pipe #1 is connected to the cold medium inlet of the heat exchanger via a pipeline. The cold medium outlet of the heat exchanger is connected to the return water inlet of the heating heat exchange station via the heating return water pipe #2. The return water outlet of the heating heat exchange station is connected to the inlet of the heating supply water pipe via a pipeline.

2. The urea plant reaction heat recovery system according to claim 1, characterized in that, It also includes a methanol regeneration tower and a second reboiler; The bottom methanol outlet of the methanol regeneration tower is connected to the methanol inlet of the first reboiler via a pipeline, and the methanol outlet of the first reboiler is connected to the middle liquid inlet of the methanol regeneration tower via a pipeline. The bottom liquid outlet of the methanol regeneration tower is connected to the methanol inlet of the second reboiler via a pipeline, and the methanol outlet of the second reboiler is connected to the central liquid inlet of the methanol regeneration tower via a pipeline.

3. The urea plant reaction heat recovery system according to claim 1, characterized in that, The outlet of the No. 1 heating return water pipe is also connected to the inlet of the No. 2 heating return water pipe through a connecting pipeline. A connecting valve is provided on the connecting pipeline, and a shut-off valve is provided at the cold medium inlet of the heat exchanger.

4. The urea plant reaction heat recovery system according to claim 1, characterized in that, A first temperature sensor is provided at the high-pressure temperature-regulating water inlet of the high-pressure washer, a first regulating valve is provided at the cold medium inlet of the high-pressure temperature-regulating water cooler, and a fourth regulating valve is provided at the temperature-regulating water inlet of the high-pressure temperature-regulating water cooler.

5. The urea plant reaction heat recovery system according to claim 1, characterized in that, A second temperature sensor is provided at the cold medium outlet of the heat exchanger, and a second regulating valve is provided on the pipeline connecting the high-pressure temperature-regulating water outlet of the high-pressure scrubber to the first reboiler.

6. The urea plant reaction heat recovery system according to claim 1, characterized in that, A third temperature sensor is provided at the heat source outlet of the first reboiler, and a third regulating valve is provided on the pipeline connecting the high-pressure scrubber and the heat medium inlet of the heat exchanger.

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