Heat recovery unit of denitration system

Abstract

The utility model relates to the field of environmental protection, and discloses a heat recovery unit of a denitration system, which comprises a urea hydrolyzer and a steam supply pipe used for heating liquid in the urea hydrolyzer, a steam trap is arranged on the steam supply pipe, and condensed water collected by the steam trap is connected to a drain tank through a conveying pipeline. Ammonia gas generated by the urea hydrolyzer is output to the ammonia-air mixer; the air input end of the ammonia-air mixer is connected with a heating fan, and the heat exchange module is used for carrying out heat exchange on water in the conveying pipeline and air input from an inlet of the heating fan. The heat recovery unit adopts waste heat of condensed water to heat inlet air of the heating fan, the efficiency of the heating fan can be improved, meanwhile, the temperature in the drainage tank is reduced, and the rime fog phenomenon disappears.

Description

Technical Field

[0001] This utility model relates to the field of environmental protection equipment technology, specifically to a heat recovery unit of a denitrification system. Background Technology

[0002] The applicant previously filed a patent application CN118384913B, which disclosed a supported catalyst and its preparation method, and a urea-to-ammonia denitrification method. The application further disclosed a urea-to-ammonia denitrification system, which includes an ammonia-air mixer, wherein the hot air of the ammonia-air mixer is derived from a heating fan.

[0003] During actual operation, we found that in winter, the condensate (temperature > 90℃) generated by the steam pipe of the urea hydrolyzer reaches the condensate tank, and the condensate tank produces a very thick white fog (water vapor formation), which seriously affects the visibility of the relevant area.

[0004] This case requires addressing the aforementioned issues while avoiding the use of additional energy sources. Utility Model Content

[0005] The purpose of this invention is to solve the above problems by providing a heat recovery unit for a denitrification system. This heat recovery unit uses the waste heat of condensate to heat the inlet air of the heating fan, which can improve the efficiency of the heating fan. At the same time, the temperature inside the condensate tank decreases and the white mist phenomenon disappears.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A heat recovery unit for a denitrification system includes a urea hydrolyzer, a steam supply pipe for heating the liquid inside the urea hydrolyzer, a steam trap on the steam supply pipe, condensate collected by the steam trap being connected to a condensate tank via a delivery pipe, and ammonia gas generated by the urea hydrolyzer being output to an ammonia-air mixer; a heating fan is connected to the air input end of the ammonia-air mixer, and a heat exchange module is also included, which is used to exchange heat between the water in the delivery pipe and the air input at the inlet of the heating fan.

[0008] Compared with the prior art, the beneficial effects of this utility model are:

[0009] This invention comprehensively considers the available heat nodes in the denitrification system. After comprehensive analysis, it is believed that the best way to utilize condensate, a low-grade heat source, is as an auxiliary heat source for the heating fan, thereby reducing the power consumption of the heating fan. At the same time, this method of controlling white mist can be achieved without additional energy.

[0010] This solution provides two heat exchange schemes. In actual construction, the sleeve scheme is used, which is more difficult to construct, has lower material costs, and lower air resistance of the heating fan. Attached Figure Description

[0011] Figure 1 This is a structural schematic diagram of one implementation of Embodiment 1;

[0012] Figure 2 This is a cross-sectional view of the conveying pipe and inner pipe of Example 1 in the direction perpendicular to the axial direction;

[0013] Figure 3 This is a structural schematic diagram of another implementation of Example 1;

[0014] Figure 4 This is a structural diagram of another implementation of Example 1. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. 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.

[0016] Example 1

[0017] refer to Figures 1-4 A heat recovery unit for a denitrification system includes a urea hydrolyzer 1 and a steam supply pipe 2 for heating the liquid in the urea hydrolyzer 1. The steam supply pipe 2 is equipped with a steam trap 3. The condensate collected by the steam trap 3 is connected to a steam trap 5 through a conveying pipe 4. The ammonia gas generated by the urea hydrolyzer 1 is output to an ammonia-air mixer 6. The air input end of the ammonia-air mixer 6 is connected to a heating fan 7. The unit also includes a heat exchange module for exchanging heat between the water in the conveying pipe 4 and the air input at the inlet of the heating fan 7.

[0018] This embodiment comprehensively considers the available heat nodes in the denitrification system. After comprehensive analysis, it is believed that the best way to utilize condensate, a low-grade heat source, is as an auxiliary heat source for the heating fan 7, thereby reducing the power consumption of the heating fan 7. At the same time, this method of controlling white mist can be achieved without additional energy.

[0019] As one possible form, it can be referenced. Figure 1 , Figure 1The diagram illustrates a sleeve-type structure. Specifically, the heat exchange module is integrated within the conveying pipe 4; the heat exchange module is an inner tube 8 disposed within the conveying pipe 4; the interlayer formed by the conveying pipe 4 and the inner tube 8 serves as a channel for condensate flow; the interior of the inner tube 8 is filled with air; and the interior of the inner tube 8 is connected to the inlet of the heating fan 7.

[0020] In this implementation, it is preferable that the airflow direction of the inner tube 8 and the condensate flow direction in the channel are opposite to each other. Of course, it is also possible to choose that the flow is in the same direction.

[0021] In some implementations, it is feasible to introduce air into the channel and condensate into the inner tube 8.

[0022] To further reduce wind resistance, the sleeve structure of this invention should be selected as a straight pipe as much as possible, avoiding serpentine pipes or other irregularly shaped pipes;

[0023] To further improve the heat exchange efficiency, the following two aspects can be optimized:

[0024] 1. By increasing the heat exchange area, the heat exchange effect is improved. Specifically, a number of heat exchange fins 9 are welded inside the inner tube 8; the heat exchange fins 9 extend along the axial direction of the inner tube 8; if air is introduced into the channel, the heat exchange fins 9 should be welded to the outer wall of the inner tube 8.

[0025] 2. By increasing the number of heat exchange modules, the diameters of the inner pipe 8 and the conveying pipe 4 are reduced. At the same time, the number of heat exchange modules is increased and multiple heat exchange modules are connected in parallel. This can indirectly increase the heat exchange area while maintaining low air resistance.

[0026] As another possible implementation of this embodiment, see reference to Figure 3 The heat exchange module is an air heat exchanger 10. The inlet of the tube side of the air heat exchanger 10 is connected to the delivery pipe 4, and the outlet of the tube side of the air heat exchanger 10 is connected to the condensate tank 5. The air inlet of the air heat exchanger 10 is connected to the atmosphere, and the air outlet of the air heat exchanger 10 is connected to the inlet of the heating fan 7.

[0027] The air heat exchanger 10 is the most common type of air heat exchanger 10 currently available on the market. It achieves heat exchange between air and condensate through finned heat exchange. The advantage of this approach is that the pipeline modification is less difficult, but the disadvantage is that the investment cost is relatively high.

[0028] In any of the above-mentioned possible forms, preferably, the inlet of the heating fan 7 is also connected to a secondary pipe 11 that is directly connected to the atmosphere; valves 12 are respectively provided between the inlet of the heating fan 7 and the secondary pipe 11, and between the inlet of the heating fan 7 and the heat exchange module; there are two heating fans 7 arranged in parallel; one of the heating fans 7 is a standby fan, and the inlet of the standby fan is directly connected to the atmosphere.

[0029] The modification of this system is implemented on only one heating fan 7. Under most operating conditions, the heating fan 7 connected to the heat exchange module of this embodiment is selected to work; if the heating fan 7 needs maintenance, it is switched to another heating fan 7.

[0030] As a theoretically feasible form, refer to Figure 4 An additional air inlet pipe 13 can be installed on the standby fan, which is connected to the heat exchange module of another heating fan 7. This allows the heat exchange module to be switched to any heating fan 7 at any time.

[0031] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements or modifications can be made without departing from the principle of the present utility model, and these improvements or modifications should also be considered within the protection scope of the present utility model.

Claims

1. A heat recovery unit for a denitrification system, comprising a urea hydrolyzer, a steam supply pipe for heating the liquid inside the urea hydrolyzer, a condensate trap provided on the steam supply pipe, condensate collected by the condensate trap being connected to a condensate tank via a conveying pipe, and ammonia gas generated by the urea hydrolyzer being output to an ammonia-air mixer; a heating fan being connected to the air input end of the ammonia-air mixer, characterized in that, It also includes a heat exchange module, which is used to exchange heat between the water in the delivery pipeline and the air input at the inlet of the heating fan.

2. The heat recovery unit according to claim 1, characterized in that, The heat exchange module is integrated inside the conveying pipeline; the heat exchange module is an inner tube installed inside the conveying pipeline; the interlayer formed by the conveying pipeline and the inner tube is a channel for condensate flow; the interior of the inner tube is filled with air; the interior of the inner tube is connected to the inlet of the heating fan.

3. The heat recovery unit according to claim 2, characterized in that, The inner tube has several heat exchange fins welded inside; the heat exchange fins extend along the axial direction of the inner tube.

4. The heat recovery unit according to claim 1, characterized in that, The heat exchange module is an air heat exchanger. The inlet of the tube side of the air heat exchanger is connected to the delivery pipe, and the outlet of the tube side of the air heat exchanger is connected to the condensate tank. The air inlet of the air heat exchanger is connected to the atmosphere, and the air outlet of the air heat exchanger is connected to the inlet of the heating fan.

5. The heat recovery unit according to claim 1, characterized in that, The inlet of the heating fan is also connected to a secondary pipe that is directly open to the atmosphere; valves are respectively provided between the inlet of the heating fan and the secondary pipe, and between the inlet of the heating fan and the heat exchange module.

6. The heat recovery unit according to claim 1, characterized in that, The heating fan consists of two units connected in parallel; one of the heating fans is a standby fan, and the inlet of the standby fan is directly connected to the atmosphere.

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