Condensate recovery device for urea-based compound fertilizer production

Abstract

This utility model discloses a condensate recovery device for the production of urea-based compound fertilizer, belonging to the field of compound fertilizer technology. It includes a buffer tank, a steam-water separator, a condensate transfer pump, a melting tank, a mixing heater, and a steam heater on a mixing tank. The condensate outlet of the steam heater is connected to the buffer tank via a pipeline with a first drain valve, and its steam inlet is connected to a steam network. The hot water outlet of the buffer tank is connected to the steam-water separator via a pipeline with a second drain valve. The gas outlet of the steam-water separator is connected to the pressure-reducing exhaust port of the buffer tank via a pipeline, and its liquid outlet is connected to the inlet of the condensate transfer pump via a pipeline. The outlet of the condensate transfer pump is connected to a boiler via a pipeline, its steam inlet is connected to a steam network via a pipeline, and its steam outlet is connected to the buffer tank via a pipeline with a third drain valve. The first drain valve between the melting tank and the buffer tank is an inverted bucket-type drain valve.

Description

Technical Field

[0001] This utility model belongs to the field of compound fertilizer technology, and specifically relates to a condensate recovery device for the production of urea-based compound fertilizer. Background Technology

[0002] Urea-based compound fertilizer is a high-concentration nitrogen, phosphorus, and potassium compound fertilizer produced by secondary processing of urea as the nitrogen source and basic fertilizers such as ammonium chloride, potassium chloride, potassium sulfate, superphosphate, and ammonium phosphate. Commonly used production methods include extrusion, granulation, slurry, and melt processing.

[0003] In existing technologies, urea needs to be melted before being mixed with other raw materials to prepare compound fertilizer. For example, patent application number CN200710143461.4 discloses a method for granulating melt slurry to prepare granular compound fertilizer, including the following steps: A. Adding urea to a low-temperature eutectic agent M, reducing the melting temperature to 113-130℃, and sending it to a mixing tank; B. Sending other raw materials to a stirrer for mixing; C. Sending the above mixture to a silo; D. Sending the above mixture to a mixing heater and heating it to 50-85℃; E. Sending the above mixture to a mixer, rapidly stirring it into a viscous material, controlling the temperature at 105-115℃, and uniformly spraying the mixture into small spherical droplets; F. Cooling it to 40-50℃ by a forced drying cold airflow, thus forming small granules of compound fertilizer.

[0004] The melting structure can be found in patent application number CN202011069356.2, which discloses a urea melting device, including: a urea melting tank, with a feed inlet at the top of the urea melting tank, at least one nozzle facing the interior of the urea melting tank on at least one side wall of the urea melting tank, and a discharge outlet at the bottom of the urea melting tank; a heat exchanger disposed in the urea melting tank; and at least one urea reflux pump disposed outside the urea melting tank, and the urea reflux pump being connected to the discharge outlet and the nozzle.

[0005] like Figure 1 As shown, existing condensate recovery devices include buffer tanks and melting tanks, mixing heaters, and steam heaters on mixing tanks. The condensate outlet of the steam heater is connected to the buffer tank via a pipeline with a first steam trap, and its steam inlet is connected to a steam network. The buffer tank discharges condensate through a hot water pump, and the first steam trap is typically a disc-type steam trap.

[0006] During use, the applicant discovered:

[0007] Because the hot water carries a lot of steam, the hot water pump is prone to cavitation, which prevents the hot water from being discharged in time, leading to steam or hot water overflow. In addition, the large steam flow rate of the melting tank not only makes it prone to damage, but also results in a low condensate recovery rate (less than 70%, condensate recovery volume less than 7 tons / h) due to the inlet temperature of the first steam trap at the condensate outlet of the steam heater in the melting tank being 158℃ and the outlet temperature being 143℃, causing steam waste. Utility Model Content

[0008] To address the aforementioned problems, this utility model provides a condensate recovery device for urea-based compound fertilizer production. It replaces some or all of the steam traps, utilizing a combination of back pressure return from the steam traps and pressurization by a condensate delivery pump. This replaces the first steam trap between the melting tank and the buffer tank from a disc-type steam trap to an inverted bucket-type steam trap, thereby improving the condensate recovery rate and allowing a large amount of condensate to be sent to the boiler for reuse. The technical solution is as follows:

[0009] This utility model provides a condensate recovery device for the production of urea-based compound fertilizer. The device includes a buffer tank 4, a melting tank 1, a mixing heater 2, and a steam heater on a mixing tank 3. The condensate outlet of the steam heater is connected to the buffer tank 4 via a pipeline with a first drain valve 8, and its steam inlet is connected to a steam network. The device also includes a steam-water separator 5 and a condensate transfer pump 6. The hot water outlet of the buffer tank 4 is connected to the steam-water separator 5 via a pipeline with a second drain valve 9. The steam-water... The gas outlet of separator 5 is connected to the pressure relief vent of buffer tank 4 via a pipeline, and its liquid outlet is connected to the inlet of condensate transfer pump 6 via a pipeline; the outlet of condensate transfer pump 6 is connected to boiler via a pipeline, its steam inlet is connected to steam network via a pipeline, and its steam outlet is connected to buffer tank 4 via a pipeline with third drain valve 10; the first drain valve 8 between melting tank 1 and buffer tank 4 is an inverted bucket type drain valve, and the other first drain valves 8 are disc type drain valves or inverted bucket type drain valves.

[0010] Furthermore, in this embodiment of the present invention, a bypass 7 is provided on the steam inlet of the steam heater of the melting tank 1, and a fourth steam trap 11 is provided on the bypass 7 and is connected to the buffer tank 4. The second steam trap 9, the third steam trap 10 and the fourth steam trap 11 are disc-type steam traps or inverted barrel-type steam traps.

[0011] Specifically, the model of the inverted bucket-type steam trap in this embodiment of the present invention is ERH120-160.

[0012] Specifically, the condensate transfer pump 6 in this embodiment of the present invention is model HP60S.

[0013] Furthermore, in this embodiment of the present invention, there are multiple melting tanks 1; the steam heaters of the multiple melting tanks 1 are arranged in parallel, and the steam inlets of their steam heaters are connected together and then connected to the steam network through steam pipe 12; each melting tank 1 has a first drain valve 8 on the condensate outlet of its steam heater, and after being connected together, it is connected to the buffer tank 4 through condensate pipe 13; the bypass 7 is provided on the steam pipe 12.

[0014] Preferably, in this embodiment of the present invention, there are two condensate transfer pumps 6, and the two condensate transfer pumps 6 are set up in a one-in-use and one-in-standby manner.

[0015] In this embodiment of the invention, the steam pressure of the steam pipeline is 0.85 MPa.

[0016] The beneficial effects of the technical solution provided by this utility model embodiment are as follows: This utility model embodiment provides a condensate recovery device for the production of urea-based compound fertilizer. By replacing some or all of the steam traps, and through a combination of back pressure return water from the steam traps and pressurization by the condensate delivery pump, the first steam trap between the melting tank and the buffer tank is replaced from a disc-type steam trap to an inverted bucket-type steam trap (with a longer service life), thereby improving the condensate recovery rate (over 85%, with a condensate recovery volume greater than 8.2 tons / hour), and sending a large amount of condensate to the boiler for reuse. Testing showed that the inlet temperature of the first steam trap at the condensate outlet of the steam heater in the melting tank was 158°C, and the outlet temperature was 90°C. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of an existing condensate recovery device.

[0018] Figure 2 This is a schematic diagram of the condensate recovery device for urea-based compound fertilizer production provided in this embodiment of the utility model.

[0019] In the diagram, 1 is a melting tank, 2 is a mixing heater, 3 is a mixing tank, 4 is a buffer tank, 5 is a steam-water separator, 6 is a condensate transfer pump, 7 is a bypass, 8 is a first steam trap, 9 is a second steam trap, 10 is a third steam trap, 11 is a fourth steam trap, 12 is a steam pipe, and 13 is a condensate pipe.

[0020] A comes from the steam website, B goes to the boiler. Detailed Implementation

[0021] To make the objectives, technical solutions and advantages of this utility model clearer, the utility model will be described in further detail below with reference to the accompanying drawings.

[0022] Example 1

[0023] See Figure 2Example 1 provides a condensate recovery device for the production of urea-based compound fertilizer. The device includes a buffer tank 4, a steam-water separator 5, a condensate transfer pump 6 (powered by steam, a steam pump), a steam heater on a melting tank 1, a steam heater on a mixing heater 2, and a steam heater on a mixing tank 3. The condensate outlet of the steam heater is connected to the buffer tank 4 (specifically, the top) via a pipe with a first drain valve 8, and its steam inlet is connected to a steam network. The hot water outlet (specifically, the bottom) of the buffer tank 4 is connected to the steam-water separator 5 (specifically, the top) via a pipe with a second drain valve 9. The gas outlet (specifically, the top) of the steam-water separator 5 is connected to the pressure-reducing exhaust port (specifically, the top) of the buffer tank 4 via a pipe, and its liquid outlet (specifically, the bottom) is connected to the inlet of the condensate transfer pump 6 via a pipe. The outlet of the condensate transfer pump 6 is connected to the boiler (specifically, the boiler's pure water storage tank) via a pipeline, its steam inlet is connected to the steam network via a pipeline (for power), and its steam outlet is connected to the buffer tank 4 (specifically, the top) via a pipeline with a third steam trap 10. The first steam trap 8 between the melting tank 1 and the buffer tank 4 is an inverted bucket-type steam trap, and other first steam traps 8 (except for the first steam trap 8 between the melting tank 1 and the buffer tank 4) are disc-type steam traps or inverted bucket-type steam traps, etc. The second steam trap 9 and the third steam trap 10 are disc-type steam traps or inverted bucket-type steam traps, etc. The steam pressure of the steam network is 0.85 MPa. In this embodiment, the height of each structure must ensure that condensate can flow; specifically, the buffer tank 4 is lower than the steam heater, the steam-water separator 5 is lower than the buffer tank 4, and the condensate transfer pump 6 is higher than the buffer tank 4.

[0024] Example 2

[0025] See Figure 2 Example 2 provides a condensate recovery device for the production of urea-based compound fertilizer. Its structure is basically the same as that of Example 1. The difference is that: the steam inlet of the steam heater of the melting tank 1 in this embodiment of the present invention is provided with a bypass 7. The bypass 7 is provided with a fourth drain valve 11 and is connected to the buffer tank 4. The fourth drain valve 11 is a disc-type drain valve or an inverted barrel-type drain valve, etc.

[0026] Example 3

[0027] Example 3 provides a condensate recovery device for the production of urea-based compound fertilizer. Its structure is basically the same as that of Example 2, except that the first drain valve 8, the second drain valve 9, the third drain valve 10 and the fourth drain valve 11 in this embodiment are all inverted barrel-type drain valves.

[0028] Example 4

[0029] Example 4 provides a condensate recovery device for urea-based compound fertilizer production. Its structure is basically the same as that of Example 2, except that: in this embodiment, the first drain valve 8 between the melting tank 1 and the buffer tank 4 is an inverted barrel-type drain valve, while the other first drain valves 8 are disc-type drain valves; the second drain valve 9, the third drain valve 10, and the fourth drain valve 11 are all disc-type drain valves. Calculations show that the condensate recovery rate is 8.2 tons / h, the condensate recovery rate is increased to over 85%, and the condensate recovery volume is increased by approximately 1.35 tons / h.

[0030] Calculate the economic benefits:

[0031] The following parameters were used for calculation: Demineralized water: 4.8 yuan / ton; Operating time: 6325h; Specific enthalpy at 0.85Mpa: 732Kcal / Kg; Heat of condensate at 90℃: 75Kcal / Kg; Condensate recovery rate: 8.2t / h; Steam unit price: 140 yuan / t.

[0032] With an annual production time of 6325 hours and a thermal efficiency of 90%, the recovered heat converted to steam is 6 * 90% * 6325 * 75 / 732 = 3483.81 tons; the revenue from recovered steam is 3483.81 * 140 = 488,000 yuan. 1.35 tons of steam are saved per hour, resulting in an annual steam saving of 6325 * 1.35 * 140 = 1,195,000 yuan. Annual water saving benefits are 82,000 * 6325 * 48,000 = 249,000 yuan. The total water saving benefits are 488,000 + 1,195,000 + 249,000 = 1,932,000 yuan.

[0033] Example 5

[0034] Example 5 provides a condensate recovery device for the production of urea-based compound fertilizer. Its structure is basically the same as that of Example 1, except that: the inverted bucket steam trap in this utility model embodiment is model ERH120-160, the condensate transfer pump 6 is model HP60S, and the disc steam trap is consistent with the prior art.

[0035] Example 6

[0036] See Figure 2 Example 6 provides a condensate recovery device for urea-based compound fertilizer production, whose structure is basically the same as that of Example 1, except that the number of melting tanks 1 in this example is multiple (2-5). The steam heaters of multiple melting tanks 1 are connected in parallel, and their steam inlets are connected together and then connected to the steam network through steam pipe 12. Each melting tank 1 has a first steam trap 8 on its steam heater condensate outlet, which is then connected together and then connected to the buffer tank 4 through condensate pipe 13. A bypass 7 is provided on the steam pipe 12.

[0037] Example 7

[0038] Example 7 provides a condensate recovery device for the production of urea-based compound fertilizer. Its structure is basically the same as that of Example 1, except that: in this example, there are two condensate transfer pumps 6, and the two condensate transfer pumps 6 are set up in a one-in-use and one-in-standby manner.

[0039] In this patent, the terms "first," "second," "third," and "fourth" serve only as distinctions and have no other special meaning. The pipeline in this patent may be equipped with pumps, valves, or flow meters as needed.

[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. The condensate water recovery device for urea-based compound fertilizer production, comprising a buffer tank (4) and a melting tank (1), a vapor heater on a mixing heater (2) and a mixing tank (3); the condensate water outlet of the vapor heater is connected with the buffer tank (4) through a pipeline with a first hydrophobic valve (8), and the vapor inlet of the vapor heater is connected with a vapor pipe network; characterized in that, The device also includes a steam-water separator (5) and a condensate transfer pump (6). The hot water outlet of the buffer tank (4) is connected to the steam-water separator (5) through a pipeline with a second drain valve (9). The gas outlet of the steam-water separator (5) is connected to the pressure relief vent of the buffer tank (4) through a pipeline, and its liquid outlet is connected to the inlet of the condensate transfer pump (6) through a pipeline. The outlet of the condensate transfer pump (6) is connected to the boiler through a pipeline, its steam inlet is connected to the steam network through a pipeline, and its steam outlet is connected to the buffer tank (4) through a pipeline with a third drain valve (10). The first drain valve (8) between the melting tank (1) and the buffer tank (4) is an inverted bucket-type drain valve, and the other first drain valves (8) are disc-type drain valves or inverted bucket-type drain valves.

2. The condensed water recovery device for urea-based compound fertilizer production according to claim 1, characterized by, The steam inlet of the steam heater of the melting tank (1) is provided with a bypass (7), and the bypass (7) is provided with a fourth steam trap (11) and is connected to the buffer tank (4). The second steam trap (9), the third steam trap (10) and the fourth steam trap (11) are disc-type steam traps or inverted barrel-type steam traps.

3. The condensed water recovery device for urea-based compound fertilizer production according to claim 2, characterized by, The model number of the inverted bucket steam trap is ERH120-160.

4. The condensate recovery device for urea-based compound fertilizer production according to claim 2, characterized in that, The condensate transfer pump (6) is model HP60S.

5. The condensate recovery device for urea-based compound fertilizer production according to claim 2, characterized in that, The number of melting tanks (1) is multiple; the steam heaters of multiple melting tanks (1) are connected in parallel, and the steam inlets of their steam heaters are connected together and then connected to the steam network through a steam pipe (12); each melting tank (1) has a first drain valve (8) on the condensate outlet of its steam heater, and after being connected together, it is connected to the buffer tank (4) through a condensate pipe (13); the bypass (7) is provided on the steam pipe (12).

6. The condensate recovery device for urea-based compound fertilizer production according to claim 1, characterized in that, The number of condensate transfer pumps (6) is two, and the two condensate transfer pumps (6) are set up in a one-in-use and one-in-standby manner.

7. The condensate recovery device for urea-based compound fertilizer production according to claim 1, characterized in that, The steam pressure of the steam pipeline network is 0.85 MPa.

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