Ammonia and urea synthesis waste heat utilization device

Abstract

The utility model discloses a waste heat utilization device for synthesis ammonia and urea, which relates to the technical field of waste heat utilization of synthesis ammonia and urea, and particularly comprises a synthesis ammonia condensate storage tank, a urea synthesis condensate tank, a first heat exchange tank, an evaporative crystallization box and a third heat exchange tank, the right side of the urea synthesis condensate tank is fixedly connected with the upper surface of the tank body, the left side of the urea synthesis condensate tank is fixedly connected with the upper surface of the tank body, the two ends of the tank body are provided with an exchange medium inlet and an exchange medium outlet respectively, and the baffle is fixedly connected to the inner side wall of the tank body. The partition plate is fixedly connected with the outer surface of the middle of the heat exchange copper pipe, the third heat exchange tank is fixedly connected with the output end of the evaporative crystallization box through a condensate pipeline, the right end of the first heat exchange tank is fixedly connected with the second heat exchange tank, and the device has the beneficial effects that the heat exchange efficiency and effect can be improved conveniently, and waste heat can be fully utilized conveniently.

Description

Technical Field

[0001] The utility model relates to the technical field of waste heat utilization of synthetic ammonia and urea, and specifically relates to a waste heat utilization device for synthetic ammonia and urea. Background Technique

[0002] Synthetic ammonia is a colorless gas produced by reacting synthesis gas (a mixture of hydrogen and nitrogen) with a catalyst. The currently widely used synthetic ammonia process is the Haber-Bosch Process, which mainly includes four steps: purification of nitrogen, preparation of synthesis gas, synthesis of ammonia, and separation of ammonia. Urea is an important nitrogen fertilizer and chemical raw material, and is also one of the main applications of synthetic ammonia. The production process of urea mainly includes three steps: synthetic ammonia, urea synthesis, and urea refining. Synthetic ammonia: The production process of synthetic ammonia is the same as that described above. Urea synthesis: Urea synthesis is obtained by reacting synthetic ammonia and carbon dioxide. The reaction is usually carried out under high temperature and high pressure, and the catalyst generally uses ammonium carbonate. The synthesis reaction is relatively complex, mainly including two stages: dynamic reaction and equilibrium reaction. The urea solution produced after the reaction is evaporated, concentrated, and crystallized to obtain urea crystals. Urea refining: Urea crystals need to be refined to improve purity. Commonly used refining methods include steps such as washing, drying, and pulverizing. The particle size and purity of urea powder can be adjusted according to different needs.

[0003] In the process of synthetic ammonia production, it is usually made from oxygen and nitrogen under high temperature and high pressure, and its temperature is usually 300 - 500 °C. After production, it requires condensate for refrigeration, and the refrigerated condensate contains relatively high heat. In the process of urea production, it also needs to maintain a high temperature and high pressure state, and its temperature is usually 180 - 200 °C. After production, it also requires condensate for refrigeration, that is, both the ammonia synthesis and urea processes will produce condensate. This part of the condensate carries a large amount of heat, and this waste heat needs to be recovered for use by other heat users in the production system. In the traditional recovery process, most directly mix the high-temperature condensates of the two and conduct heat exchange with heat users to recover waste heat. This method has low efficiency, insufficient recovery of waste heat, and high waste of thermal energy. Therefore, there is an urgent need for a waste heat utilization device for synthetic ammonia and urea to solve the above problems. Content of the Utility Model

[0004] (I) Technical Problems to be Solved

[0005] Aiming at the deficiencies of the prior art, the utility model provides a waste heat utilization device for synthetic ammonia and urea, which solves the problems put forward in the above background technique.

[0006] (II) Technical Solutions

[0007] To achieve the above object, the utility model is realized by the following technical solutions: A device for utilizing the waste heat of synthetic ammonia and urea, including a synthetic ammonia condensate storage tank, a urea synthesis condensate tank, a first heat exchange tank, an evaporation crystallization tank and a third heat exchange tank. The lower surface of the urea synthesis condensate tank is respectively provided with a heat supply pipe and a waste heat recovery pipe. The right side of the urea synthesis condensate tank is fixedly connected with a low-temperature condensate inlet pipe, and the left side of the urea synthesis condensate tank is fixedly connected with a high-temperature condensate discharge pipe. The first heat exchange tank includes a tank body, a baffle plate, heat exchange copper pipes and a partition plate. The upper surface of the tank body is respectively provided with a condensate inlet and a condensate outlet. The two ends of the tank body are respectively provided with an exchange medium inlet and an exchange medium outlet. The baffle plate is fixedly connected to the inner side wall of the tank body. The heat exchange copper pipes are fixedly connected to one side surface of the baffle plate. The partition plate is fixedly connected to the outer surface of the middle part of the heat exchange copper pipes. The output end of the synthetic ammonia condensate storage tank is fixedly connected with the condensate inlet through a condensate pipeline. The heat supply pipe is fixedly connected with the condensate outlet through a condensate pipeline. The second heat exchange tank is fixedly connected to the left end of the first heat exchange tank. The left end of the second heat exchange tank is fixedly connected with a first fan. The evaporation crystallization tank is fixedly connected with one end through a condensate pipeline. The third heat exchange tank is fixedly connected with the output end of the evaporation crystallization tank through a condensate pipeline. The right end of the first heat exchange tank is fixedly connected with a drying tank.

[0008] Optionally, a plurality of the heat exchange copper pipes are provided and are evenly distributed in a circular array manner, and the heat exchange copper pipes are spirally distributed.

[0009] Optionally, a plurality of the partition plates are provided and are evenly distributed in a rectangular array manner, and notches are formed on the outer surface of the partition plates.

[0010] Optionally, the internal structures of the second heat exchange tank and the third heat exchange tank are the same as the internal structure of the first heat exchange tank.

[0011] Optionally, a second fan is fixedly connected to the left end of the third heat exchange tank, and a heat user supply pipe is fixedly connected to the right end of the third heat exchange tank.

[0012] Optionally, the upper surface of the third heat exchange tank is fixedly connected with one end of the low-temperature condensate inlet pipe through a condensate pipeline, and a circulation pump is fixedly connected to the middle part of the condensate pipeline above the third heat exchange tank.

[0013] Optionally, a moisture discharge pipe is fixedly connected to the outer surface of the drying tank.

[0014] Optionally, electromagnetic valves are fixedly connected to the output end of the synthetic ammonia condensate storage tank, one end of the waste heat recovery pipe, the middle part of the high-temperature condensate discharge pipe, the input end of the evaporation crystallization tank and one end of the low-temperature condensate inlet pipe.

[0015] The utility model provides a device for utilizing the waste heat of synthetic ammonia and urea, which has the following beneficial effects:

[0016] 1. For the device for utilizing the waste heat of synthetic ammonia and urea, through the setting of the first heat exchange tank, the device for utilizing the waste heat of synthetic ammonia and urea has the effect of improving the heat exchange efficiency and effect. Through the cooperative setting of the baffle, the heat exchange copper tube and the partition plate, during the use process, the heat exchange efficiency and effect between the high-temperature condensate and other media can be better improved, thereby achieving the purpose of facilitating the improvement of the heat exchange efficiency and effect.

[0017] 2. For the device for utilizing the waste heat of synthetic ammonia and urea, through the setting of the synthetic ammonia condensate storage tank, the urea synthesis condensate tank, the first heat exchange tank, the second heat exchange tank, the first fan, the evaporation crystallization tank and the drying tank, the device for utilizing the waste heat of synthetic ammonia and urea has the effect of facilitating the full utilization of waste heat. Through the setting of the first heat exchange tank and the second heat exchange tank, during the use process, the high-temperature condensate flowing out from the synthetic ammonia condensate storage tank, in cooperation with the setting of the first fan, can exchange the heat of the high-temperature condensate flowing out from the synthetic ammonia condensate storage tank and the urea synthesis condensate tank with air, and the heat after exchange is supplied to the drying tank to provide energy for the drying process in the urea refining process, and can also be directly supplied to the evaporation crystallization tank to provide energy for the urea evaporation crystallization process. Moreover, the condensate after being utilized by the evaporation crystallization tank still has a certain temperature, and at this time, heat exchange can occur in the third heat exchange tank and be supplied to the heat user for reuse through the heat user supply pipe, achieving the purpose of facilitating the full utilization of waste heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the principle structure of the present utility model;

[0019] Figure 2 is a three-dimensional structure schematic diagram of the interior of the first heat exchange tank of the present utility model;

[0020] Figure 3 is a front view sectional structure schematic diagram of the first heat exchange tank of the present utility model;

[0021] Figure 4 is a three-dimensional structure schematic diagram of the heat exchange copper tube and the partition plate of the present utility model;

[0022] Figure 5 of the present utility model Figure 1 is a schematic diagram of the structure at position A.

[0023] In the figure: 1. Ammonia synthesis condensate storage tank; 2. Urea synthesis condensate tank; 201. Heating pipe; 202. High-temperature condensate discharge pipe; 203. Waste heat recovery pipe; 204. Low-temperature condensate inlet pipe; 3. First heat exchange tank; 301. Tank body; 302. Condensate feed inlet; 303. Condensate outlet; 304. Exchange medium inlet; 305. Exchange medium outlet; 306. Baffle; 307. Heat exchange copper pipe; 308. Partition board; 309. Notch; 4. Second heat exchange tank; 5. First fan; 6. Evaporation crystallization tank; 7. Condensate pipeline; 8. Solenoid valve; 9. Third heat exchange tank; 10. Second fan; 11. Circulation pump; 12. Heat user supply pipe; 13. Drying tank; 14. Moisture discharge pipe. Detailed implementation manners

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Embodiment 1

[0025] The technical solution provided by the present invention: A device for utilizing the waste heat of ammonia synthesis and urea includes an ammonia synthesis condensate storage tank 1, a urea synthesis condensate tank 2, a first heat exchange tank 3, an evaporation crystallization tank 6 and a third heat exchange tank 9. The first heat exchange tank 3 includes a tank body 301, a baffle 306, heat exchange copper pipes 307 and a partition board 308. A condensate feed inlet 302 and a condensate outlet 303 are respectively arranged on the upper surface of the tank body 301. An exchange medium inlet 304 and an exchange medium outlet 305 are respectively arranged at both ends of the tank body 301. The baffle 306 is fixedly connected to the inner side wall of the tank body 301. The heat exchange copper pipes 307 are fixedly connected to one side surface of the baffle 306. There are several heat exchange copper pipes 307 and they are evenly distributed in a circular array. The heat exchange copper pipes 307 are spirally distributed. The partition board 308 is fixedly connected to the outer surface of the middle part of the heat exchange copper pipes 307. There are several partition boards 308 and they are evenly distributed in a rectangular array. A notch 309 is formed on the outer surface of the partition board 308. The output end of the ammonia synthesis condensate storage tank 1 is fixedly connected to the condensate feed inlet 302 through a condensate pipeline 7 and is fixedly connected to the condensate outlet 303 through the condensate pipeline 7.

[0026] In order to facilitate improving the heat exchange efficiency and effect, as shown in the attached Figures 1 to 5As shown in the figure, the present application adopts the following structure. By setting the first heat exchange tank 3, the synthetic ammonia and urea waste heat utilization device has the effect of improving the heat exchange efficiency and effect. Through the combined setting of the baffle 306, the heat exchange copper pipe 307 and the partition plate 308, during use, the condensate whose temperature has risen during the synthetic ammonia preparation process is discharged into the interior of the first heat exchange tank 3 from the condensate inlet 302 and is located between the two baffles 306, and then discharged from the condensate outlet 303. During this process, after the condensate enters from the condensate inlet 302, through the setting of a number of partition plates 308 with notches 309, when the condensate flows inside the tank body 301, it flows in an S shape, greatly extending the residence time of the high-temperature condensate inside the tank body 301. Through the setting of the baffle 306 and the heat exchange copper pipe 307, a first fan 5 is installed at the end of the exchange medium inlet 304. After the first fan 5 pumps in air, at this time, the air will pass through a number of heat exchange copper pipes 307 to the other side. During this process, heat exchange can occur inside the heat exchange copper pipes 307, and the spiral heat exchange copper pipes 307 improve the residence time of the air inside the tank body 301, thereby effectively improving the heat exchange efficiency and effect. This device can better improve the heat exchange efficiency and effect between the high-temperature condensate and other media, thus achieving the purpose of facilitating the improvement of heat exchange efficiency and effect; Embodiment 2

[0027] The present utility model provides a technical solution: The lower surface of the urea synthesis condensate tank 2 is respectively provided with a heat supply pipe 201 and a waste heat recovery pipe 203. The right side of the urea synthesis condensate tank 2 is fixedly connected with a low-temperature condensate inlet pipe 204. The left side of the urea synthesis condensate tank 2 is fixedly connected with a high-temperature condensate discharge pipe 202, which is fixedly connected to the condensate outlet 303 through a condensate pipeline 7. The second heat exchange tank 4 is fixedly connected to the left end of the first heat exchange tank 3. The left end of the second heat exchange tank 4 is fixedly connected with a first fan 5. The internal structures of the second heat exchange tank 4 and the third heat exchange tank 9 are the same as the internal structure of the first heat exchange tank 3. The evaporation crystallization tank 6 is fixedly connected to one end of the high-temperature condensate discharge pipe 202 through a condensate pipeline 7. The third heat exchange tank 9 is fixedly connected to the output end of the evaporation crystallization tank 6 through a condensate pipeline 7. The left end of the third heat exchange tank 9 is fixedly connected with a second fan 10. The right end of the third heat exchange tank 9 is fixedly connected with a heat user supply pipe 12. The upper surface of the third heat exchange tank 9 is fixedly connected to one end of the low-temperature condensate inlet pipe 204 through a condensate pipeline 7. The middle part of the condensate pipeline 7 is fixedly connected with a circulation pump 11 above the third heat exchange tank 9. The right end of the first heat exchange tank 3 is fixedly connected with a drying tank 13. The output end of the synthetic ammonia condensate storage tank 1, one end, the middle part of the waste heat recovery pipe 203, the input end of the evaporation crystallization tank 6 and one end are all fixedly connected with electromagnetic valves 8.

[0028] In order to facilitate the full utilization of waste heat, as shown in the appendix Figures 1 to 5 As shown, the present application adopts the following structure. Through the setting of the synthetic ammonia condensate storage tank 1, the urea synthesis condensate tank 2, the first heat exchange tank 3, the second heat exchange tank 4, the first fan 5, the evaporation crystallization tank 6 and the drying tank 13, the synthetic ammonia and urea waste heat utilization device has the effect of facilitating the full utilization of waste heat. Through the setting of the first heat exchange tank 3 and the second heat exchange tank 4, during use, the high-temperature condensate flowing out of the synthetic ammonia condensate storage tank 1 first enters the interior of the tank body 301 through the condensate feed port 302, and the high-temperature condensate discharged from the urea synthesis condensate tank 2 also enters the interior of the second heat exchange tank 4. With the setting of the first fan 5, air is introduced from the left end of the second heat exchange tank 4, which can exchange the heat of the high-temperature condensate flowing out of the synthetic ammonia condensate storage tank 1 and the urea synthesis condensate tank 2 with the air, heat up the air and supply it to the drying tank 13 to provide energy for the drying process in the urea refining process. When the drying tank 13 is not working, the first fan 5 is also turned off. At this time, the high-temperature condensate discharged from the synthetic ammonia condensate storage tank 1 directly enters the interior of the urea synthesis condensate tank 2 to directly provide heat energy for the urea synthesis step in the urea synthesis condensate tank 2, and the waste heat that has been utilized can be directly discharged into the interior of the evaporation crystallization tank 6 through the high-temperature condensate discharge pipe 202, or the high-temperature condensate that has been heat-exchanged inside the second heat exchange tank 4 can also be directly discharged into the interior of the evaporation crystallization tank 6, which can be directly supplied to the evaporation crystallization tank 6 to provide energy for the urea evaporation crystallization process inside the evaporation crystallization tank 6. And the condensate after being utilized by the evaporation crystallization tank 6 still has a certain temperature. Similarly, the high-temperature condensate can exchange heat with the air pumped by the second fan 10 in the third heat exchange tank 9 and be supplied to the heat user for reuse through the heat user supply pipe 12. Other media can also be directly introduced at the second fan 10 and supplied to the heat user. That is, the waste heat discharged from the synthetic ammonia condensate storage tank 1 can directly provide heat energy for the urea synthesis condensate tank 2 and can also directly provide energy for the drying process of urea refining. The waste heat discharged from the urea synthesis condensate tank 2 can also directly provide energy for the drying process of urea refining and directly supply heat for the evaporation crystallization process, thereby achieving the purpose of facilitating the full utilization of waste heat.

[0029] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. A synthetic ammonia and urea waste heat utilization device, comprising a synthetic ammonia condensate storage tank (1), a urea synthetic condensate tank (2), a first heat exchange tank (3), a second heat exchange tank (4), an evaporation crystallization tank (6) and a third heat exchange tank (9), characterized in that: The lower surface of the urea synthesis condensate tank (2) is respectively provided with a heat supply pipe (201) and a waste heat recovery pipe (203); the right side of the urea synthesis condensate tank (2) is fixedly connected with a low-temperature condensate inlet pipe (204); the left side of the urea synthesis condensate tank (2) is fixedly connected with a high-temperature condensate outlet pipe (202); the first heat exchange tank (3) comprises a tank body (301), a baffle (306), a heat exchange copper tube (307) and a partition (308); the upper surface of the tank body (301) is respectively provided with a condensate feed inlet (302) and a condensate outlet (303); both ends of the tank body (301) are respectively provided with an exchange medium inlet (304) and an exchange medium outlet (305); the baffle (306) is fixedly connected to the inner side wall of the tank body (301); the heat exchange copper tube (307) is fixedly connected to the baffle (306); and the heat exchange copper tube (307) is fixedly connected to the baffle (308). On one side of the heat exchanger (306), the partition (308) is fixedly connected to the outer surface of the middle part of the heat exchange copper tube (307); the output end of the synthetic ammonia condensate storage tank (1) is fixedly connected to the condensate feed port (302) via the condensate pipe (7); the heat supply pipe (201) is fixedly connected to the condensate outlet (303) via the condensate pipe (7); the second heat exchange tank (4) is fixedly connected to the left end of the first heat exchange tank (3); the left end of the second heat exchange tank (4) is fixedly connected to the first fan (5); the evaporation crystallization box (6) is fixedly connected to one end of the high-temperature condensate discharge pipe (202) via the condensate pipe (7); the third heat exchange tank (9) is fixedly connected to the output end of the evaporation crystallization box (6) via the condensate pipe (7); and the right end of the first heat exchange tank (3) is fixedly connected to the drying tank (13).

2. The device for utilizing waste heat from synthetic ammonia and urea according to claim 1, characterized in that: A plurality of the heat exchange copper tubes (307) are arranged and are evenly distributed in a ring array, and the heat exchange copper tubes (307) are distributed in a spiral shape.

3. The device for utilizing waste heat from synthetic ammonia and urea according to claim 1, characterized in that: A plurality of partitions (308) are provided and are evenly distributed in a rectangular array, and a notch (309) is provided on the outer surface of the partition (308).

4. The device for utilizing waste heat from synthetic ammonia and urea according to claim 1, characterized in that: The internal structures of the second heat exchange tank (4) and the third heat exchange tank (9) are the same as the internal structure of the first heat exchange tank (3).

5. The device for utilizing waste heat from synthetic ammonia and urea according to claim 1, characterized in that: The left end of the third heat exchange tank (9) is fixedly connected to a second fan (10), and the right end of the third heat exchange tank (9) is fixedly connected to a heat user supply pipe (12).

6. The device for utilizing waste heat from synthetic ammonia and urea according to claim 1, characterized in that: The upper surface of the third heat exchange tank (9) is fixedly connected to one end of the low-temperature condensate inlet pipe (204) via a condensate pipe (7), and a circulating pump (11) is fixedly connected to the middle portion of the condensate pipe (7) located above the third heat exchange tank (9).

7. The device for utilizing waste heat from synthetic ammonia and urea according to claim 1, characterized in that: A moisture exhaust pipe (14) is fixedly connected to the outer surface of the drying tank (13).

8. The device for utilizing waste heat from synthetic ammonia and urea according to claim 1, characterized in that: The output end of the synthetic ammonia condensate storage tank (1), one end of the waste heat recovery pipe (203), the middle of the high-temperature condensate discharge pipe (202), the input end of the evaporation crystallization box (6) and one end of the low-temperature condensate inlet pipe (204) are all fixedly connected with a solenoid valve (8).

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