Ammonia evaporation exhaust gas heat exchange condensing device

Abstract

This utility model discloses a heat exchange and condensation device for ammonia vapor exit gas, comprising a shell, the inner cavity of which is divided into multiple vertically arranged cavities by several end caps in the middle. The cavities on the upper and lower sides of any one of the end caps are respectively an upper cavity and a lower cavity. The upper part of each cavity is an air inlet, and the lower part is a gas-liquid separation section. A heat exchange section is provided between the air inlet and the gas-liquid separation section, which can exchange heat and condense the ammonia vapor exit gas passing downwards through it. Each gas-liquid separation section has a gas outlet at the upper part and a liquid outlet at the lower part. The gas outlet of the upper cavity is connected to the corresponding air inlet of the lower cavity through a transition gas pipe, and the gas outlet of the bottommost lower cavity is connected to the air inlet of an ammonia absorption tower. A condensate pool is formed at the lower part of the gas-liquid separation section of the upper cavity, and the liquid in the condensate pool can exchange heat with the gas in the corresponding air inlet of the lower cavity through the end caps. This utility model can output liquids with multiple different temperature ranges, realizing heat recovery and rational redistribution.

Description

Technical Field

[0001] This utility model relates to the field of heat exchange device technology, and in particular to a heat exchange and condensation device for ammonia stripping gas. Background Technology

[0002] In industrial alkali production, ammonia gas is often recovered from the mother liquor by ammonia stripping. However, ammonia recovery typically requires cooling via a heat exchanger to improve efficiency. Common heat exchangers only allow heat exchange between the effluent gas and the internal coolant, and the coolant is usually transported through a single circulation pipeline. The temperature of the cooling water after heat exchange is essentially uniform and cannot be adjusted, limiting the heat reuse pathway. Furthermore, the condensate is usually discharged after separation from the ammonia gas, and its temperature is relatively low with limited applications. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the shortcomings of the existing technology, this utility model provides an ammonia vapor heat exchange and condensation device that can output liquids with different temperature ranges, so as to realize heat recovery and rational redistribution and utilization.

[0004] Technical Solution: To achieve the above objectives, this utility model provides a heat exchange and condensation device for ammonia vapor exit gas, comprising a shell. The inner cavity of the shell is divided into multiple vertically arranged cavities by several end caps in the middle. The cavities on the upper and lower sides of any one of the end caps are respectively an upper cavity and a lower cavity. The upper part of each cavity is an air inlet, and the lower part is a gas-liquid separation section. A heat exchange section is provided between the air inlet and the gas-liquid separation section, which can exchange heat and condense the ammonia vapor exit gas passing downward through it. Each gas-liquid separation section has a gas outlet at the upper part and a liquid outlet at the lower part. The gas outlet of the upper cavity is connected to the air inlet of the corresponding lower cavity through a transition gas pipe, and the gas outlet of the bottommost lower cavity is connected to the air inlet of the ammonia absorption tower. A condensate pool is formed at the lower part of the gas-liquid separation section of the upper cavity, and the liquid in the condensate pool can exchange heat with the gas in the air inlet of the corresponding lower cavity through the end caps.

[0005] Furthermore, the gas-liquid separation section of the upper cavity has a reflux outlet at its lower part and a reflux inlet at its middle part, and the reflux outlet and the reflux inlet are connected by a reflux pipeline.

[0006] Furthermore, the gas-liquid separation section of the upper cavity is also equipped with a liquid level detection device, which is electrically connected to the corresponding drain pump through a control module to control the opening and closing of the drain pump.

[0007] Furthermore, the end cap is a spherical partition with an upward convex center.

[0008] Furthermore, the reflux inlet is directly opposite the center of the spherical surface of the end cap, and the outlet of the transition gas pipe is directly opposite the center of the lower spherical surface of the end cap.

[0009] Furthermore, the heat exchange section includes a plurality of heat exchange tubes, which are arranged vertically, and the air inlet section is connected vertically to the corresponding gas-liquid separation section through the plurality of heat exchange tubes.

[0010] Furthermore, the upper and lower ends of the multiple heat exchange tubes are respectively fixedly installed relative to the shell through tube sheets, and a coolant channel is formed between the two tube sheets. The coolant channel is a baffle channel from bottom to top.

[0011] Furthermore, the heat exchange tube is a corrugated tube.

[0012] Beneficial Effects: This utility model discloses an ammonia vapor heat exchange and condensation device. By dividing the device into multiple chambers, it achieves staged heat exchange and collects condensate at different temperatures at the bottom of each chamber. This condensate can be distributed and used according to temperature requirements, saving raw water consumption. Furthermore, the primary heat exchange involves heat exchange between the liquid and the ammonia vapor. The selected liquid can be changed as needed, and the temperature of the liquid after heat exchange can be controlled by pre-designing the length of the heat exchange section. Therefore, this solution can output liquids with various temperature ranges, achieving heat recovery and rational redistribution. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of one embodiment of the heat exchange and condensation device of this utility model. Detailed Implementation

[0014] The present invention will be further described below with reference to the accompanying drawings.

[0015] As attached Figure 1 The ammonia vapor heat exchange and condensation device includes a shell 1. The inner cavity of the shell 1 is divided into multiple vertically arranged cavities by several end caps 2 in the middle. The cavities on the upper and lower sides of any one end cap 2 are respectively an upper cavity and a lower cavity. The upper part of each cavity is an air inlet 3, and the lower part is a gas-liquid separation section 4. A heat exchange section 5 is provided between the air inlet 3 and the gas-liquid separation section 4. The heat exchange section 5 can exchange heat and condense the ammonia vapor passing downward through it. The upper part of each gas-liquid separation section 4 is provided with a gas outlet 41. The gas outlet 41 of the upper cavity is connected to the air inlet 3 of the corresponding lower cavity through a transition gas pipe 6. The gas outlet 41 of the bottommost lower cavity is connected to the air inlet of the ammonia absorption tower. A condensate pool is formed at the lower part of the gas-liquid separation section 4 of the upper cavity. The liquid in the condensate pool can exchange heat with the gas in the air inlet 3 of the corresponding lower cavity through the end caps 2. Each of the gas-liquid separation units 4 is provided with a drain port 42 at its lower part.

[0016] After the ammonia stripping gas is drawn out from the top or side of the ammonia stripping tower, it is directly sent into the uppermost air inlet 3 from the air inlet at the top of the shell 1. Then, under the action of air pressure, it passes through multiple chambers in sequence to achieve staged heat exchange. After heat exchange in each heat exchange section, the condensate formed is separated from the gas in the corresponding gas-liquid separation section 4 and gathers to form a condensate pool. The condensate produced by condensation is one of the output hot liquids of this device and still has a certain amount of heat. The condensate temperature in the multiple chambers from top to bottom is different and gradually decreases. In actual distribution, it can be used for different purposes according to different temperatures.

[0017] After multi-stage heat exchange and condensation, the heat recovery effect is better, the ammonia recovery efficiency is also improved accordingly, and the recovery rate of condensate is increased, greatly reducing the amount of raw water used. In other words, compared with existing heat exchange devices, this solution uses less total water while achieving the same ammonia recovery efficiency, and can produce liquids with various temperature ranges. These liquids can be used as needed, enabling heat recovery and rational redistribution.

[0018] In addition, each heat exchange section 5 exchanges heat with the ammonia-vaporized gas through a liquid medium, and the vertical length of the heat exchange section in each chamber can be adjusted according to the required heat exchange capacity. The temperature of the output liquid after heat exchange is controlled by indirectly controlling the heat exchange duration. The liquid used for heat exchange with the ammonia-vaporized gas can be raw water or process water. For example, by introducing cold ammonia-vaporized mother liquor into the heat exchange section, controllable preheating of the cold mother liquor can be achieved. Introducing cooling water allows for heat reuse through another heat exchange system at a remote location, or it can be directly applied to processes such as ash removal and salt removal based on the temperature after heat exchange, thereby improving the reaction rate of the corresponding processes.

[0019] Considering that the number of processes using water at different temperatures is limited in the actual process flow, in one embodiment, only two chambers are formed, one upper and one lower. If the vertical length of the heat exchange section in both chambers is designed according to the required temperature of the liquid flowing through them, then in order to make the output ammonia gas as low as possible, as much heat exchange as possible is needed between the condensate pool at the bottom of the upper chamber and the gas inlet 3 of the lower chamber.

[0020] Therefore, the gas-liquid separation section 4 of the upper cavity is provided with a return outlet 43 at its lower part and a return inlet 44 in its middle part. The return outlet 43 and the return inlet 44 are connected by a return pipeline. The manifold is equipped with a return pump, which actively extracts the liquid at the bottom of the condensate tank and pumps it upward to return it into the condensate tank from the middle. This causes the liquid in the condensate tank to flow vertically downward, thereby guiding the newly collected condensate downward to contact the end cap 2 for heat exchange. The condensate that has been heat-exchanged is then repeatedly mixed with the newly dripping condensate and circulated for heat exchange multiple times through the return flow, effectively improving the heat exchange efficiency and effect of the middle section.

[0021] The gas-liquid separation section 4 of the upper cavity is also equipped with a liquid level detection device 45, which is electrically connected to the corresponding drain pump 42 via a control module to control the opening and closing of the drain pump. Through liquid level control, draining begins when the liquid level reaches the upper limit, and the discharged condensate is directed to a suitable destination based on the actual temperature, for example, sent to a distillation column. Draining is stopped when the liquid level drops to the lower limit to ensure sufficient liquid circulation for heat exchange. Draining is not performed during the liquid level rise process, which prolongs the number of condensate circulations and the residence time, allowing for repeated heat exchange to absorb as much heat as possible.

[0022] The end cap 2 is a spherical baffle with an upward convex center. This increases the heat exchange area between the liquid on the upper side and the gas on the lower side, thereby improving heat exchange efficiency.

[0023] The reflux inlet 44 is directly opposite the middle of the upper spherical surface of the end cap 2, and the outlet end of the transition gas pipe 6 is directly opposite the middle of the lower spherical surface of the end cap 2.

[0024] The heat exchange section 5 includes a plurality of heat exchange tubes 51, which are arranged vertically. The air inlet section 3 is connected vertically to the corresponding gas-liquid separation section 4 through the plurality of heat exchange tubes 51. The vertical arrangement of the heat exchange tubes allows the condensate to slide down the tube wall under the assistance of gravity, forming a faster liquid flow on the inner side of the tube wall, which accelerates heat exchange and also facilitates the accumulation of condensate.

[0025] The upper and lower ends of multiple heat exchange tubes 51 are fixedly installed relative to the shell 1 via tube sheets. A coolant channel 52 is formed between two tube sheets, and the coolant channel 52 is a bottom-to-top baffle channel. Multiple horizontally arranged baffles form a baffle channel between the two tube sheets, and adjacent baffles are fixedly supported by spacer tubes to maintain a stable spacing and structure, preventing damage to the heat exchange tubes due to thermal expansion differences. The gas in the tube side and the liquid in the shell side form a counter-current heat exchange, improving heat exchange efficiency and reducing the overall tower height.

[0026] Preferably, the heat exchange tube 51 is a corrugated tube. This increases the heat exchange area while allowing for expansion and contraction within a certain range, which helps the condensate to collect and prevents scale buildup on the tube wall from causing blockage.

[0027] The above are merely preferred embodiments of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A heat exchange and condensation device for ammonia vapor discharge, characterized in that: Includes a shell (1), the inner cavity of the shell (1) is divided by several end caps (2) in the middle to form a plurality of vertically arranged cavities, the cavities on the upper and lower sides relative to any one of the end caps (2) are respectively the upper cavity and the lower cavity; The upper part of each of the multiple cavities is an air inlet (3), and the lower part is a gas-liquid separation section (4). A heat exchange section (5) is provided between the air inlet (3) and the gas-liquid separation section (4). The heat exchange section (5) can exchange heat and condense the ammonia vapor that passes downward through itself. The gas-liquid separation unit (4) is provided with a gas outlet (41) at the top and a liquid outlet (42) at the bottom. The gas outlet (41) of the upper cavity is connected to the air inlet (3) of the corresponding lower cavity through a transition gas pipe (6), and the gas outlet (41) of the bottommost lower cavity is connected to the air inlet of the ammonia absorption tower. A condensate pool is formed in the lower part of the gas-liquid separation section (4) of the upper cavity, and the liquid in the condensate pool can exchange heat with the gas in the corresponding air inlet section (3) of the lower cavity through the end cap (2).

2. The ammonia vapor heat exchange and condensation device according to claim 1, characterized in that: The gas-liquid separation section (4) of the upper cavity has a reflux outlet (43) at its lower part and a reflux inlet (44) in its middle part. The reflux outlet (43) and the reflux inlet (44) are connected by a reflux pipeline.

3. The ammonia vapor heat exchange and condensation device according to claim 2, characterized in that: The gas-liquid separation section (4) of the upper cavity is also equipped with a liquid level detection device, which is electrically connected to the corresponding drain pump (42) through a control module to control the opening and closing of the drain pump.

4. The ammonia vapor heat exchange and condensation device according to claim 3, characterized in that: The end cap (2) is a spherical partition with an upward convex center.

5. The ammonia vapor heat exchange and condensation device according to claim 4, characterized in that: The reflux inlet (44) is directly opposite the middle of the upper spherical surface of the end cap (2), and the outlet of the transition gas pipe (6) is directly opposite the middle of the lower spherical surface of the end cap (2).

6. The ammonia vapor heat exchange and condensation device according to claim 1, characterized in that: The heat exchange section (5) includes a plurality of heat exchange tubes (51), which are arranged vertically. The air inlet section (3) is connected vertically to the corresponding gas-liquid separation section (4) through the plurality of heat exchange tubes (51).

7. The ammonia vapor heat exchange and condensation device according to claim 6, characterized in that: The upper and lower ports of the multiple heat exchange tubes (51) are fixedly installed relative to the shell (1) through tube sheets, and a coolant channel (52) is formed between the two tube sheets. The coolant channel (52) is a baffle channel from bottom to top.

8. The ammonia vapor heat exchange and condensation device according to claim 7, characterized in that: The heat exchange tube (51) is a corrugated tube.

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