An energy-saving device for nitric acid recovery
By introducing components such as a demineralized water preheater and heater into the nitric acid recovery unit, the problem of insufficient recovery of nitrogen oxide heat energy was solved, achieving efficient utilization of heat energy and saving of circulating water, thereby reducing production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XIAN SHAANGU POWER CO LTD
- Filing Date
- 2025-04-16
- Publication Date
- 2026-06-02
AI Technical Summary
In existing nitric acid recovery devices, the heat energy recovery and utilization rate of nitrogen oxides and high-temperature nitrogen oxide gases is low, resulting in insufficient heat energy recovery, which increases production costs and circulating water consumption.
The system employs components such as a demineralized water preheater, first and second demineralized water heaters, and a nitrogen oxide compressor. By recovering and utilizing the heat from nitrogen oxides in the demineralized water, it reduces the amount of circulating water used and increases the temperature of the demineralized water to reduce the amount of steam used in the steam drum.
It improves the heat energy recovery and utilization rate, reduces the use of circulating water, lowers production costs, and brings long-term economic benefits.
Smart Images
Figure CN224316148U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of chemical process technology, and relates to nitric acid recovery, specifically to an energy-saving device for nitric acid recovery. Background Technology
[0002] With the continuous advancement of science and technology and the maturation of nitric acid production processes, the comprehensive utilization of nitric acid decomposition products has emerged. By combining the principles of nitric acid production processes to recover nitric acid decomposition products and produce nitric acid, greater economic benefits can be generated.
[0003] In existing nitric acid recovery devices, the waste heat utilization of high-temperature nitrogen oxide gas entering the device typically involves using a waste heat boiler, preheating the tail gas, or preheating demineralized water to lower the temperature of the nitrogen oxide gas. Then, circulating water is used to further reduce the temperature of the nitrogen oxides to a suitable level before they enter the next processing unit. Since the nitrogen oxides are pressurized and reach a high temperature, nitric acid recovery devices usually employ rapid cooling with circulating water to lower the gas temperature.
[0004] Existing nitric acid recovery devices fail to fully recover and utilize the heat energy of nitrogen oxides discharged from waste heat boilers and the heat energy of high-temperature nitrogen oxide gas after pressurization. During the heat recovery process, the demineralized water used in the waste heat boiler is only preheated before entering the steam drum, and a large amount of circulating water is used to cool the nitrogen oxides. As a result, some heat energy is not fully recovered and utilized, and a large amount of circulating water is consumed, increasing production costs. Summary of the Invention
[0005] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide an energy-saving device for nitric acid recovery, so as to solve the technical problem that the recovery and utilization rate of the heat energy of nitrogen oxides discharged from the waste heat boiler and the heat energy of the high temperature nitrogen oxide gas after pressurization of nitrogen oxides in the existing nitric acid recovery device needs to be further improved.
[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:
[0007] An energy-saving device for nitric acid recovery includes a demineralized water preheater, the outlet of which is connected to the inlet of a second demineralized water heater, and the outlet of the second demineralized water heater is connected to the inlet of a nitrogen oxide cooler.
[0008] It also includes a nitrogen oxide compressor, the discharge port of which is connected to the inlet of the first demineralized water heater, and the discharge port of the first demineralized water heater is connected to the inlet of the rapid cooler.
[0009] It also includes a demineralized water boiler feed pump, the outlet of which is connected to the inlet of the first demineralized water heater, the outlet of the first demineralized water heater is connected to the inlet of the second demineralized water heater, and the outlet of the second demineralized water heater is connected to the inlet of the demineralized water preheater.
[0010] This utility model also has the following technical features:
[0011] Specifically, it also includes a waste heat boiler, wherein the low-temperature material outlet of the boiler tube side of the waste heat boiler is connected to the feed inlet of the tail gas preheater, and the discharge outlet of the tail gas preheater is connected to the feed inlet of the demineralized water preheater.
[0012] Specifically, the outlet of the demineralized water preheater is also connected to the steam drum feedwater inlet of the steam drum, the steam drum downcomer interface of the steam drum is also connected to the boiler shell downcomer interface of the waste heat boiler, the boiler shell riser interface of the waste heat boiler is also connected to the steam drum riser interface of the steam drum, and the steam drum steam outlet of the steam drum is also connected to the steam outflow zone external pipe.
[0013] Specifically, the high-temperature material inlet of the boiler tube side of the waste heat boiler is also connected to the outer tube of the nitrogen oxide self-bound zone.
[0014] Specifically, the outlet of the nitrogen oxide cooler is also connected to the inlet of the scrubbing tower, the outlet of the scrubbing tower is also connected to the inlet of the nitrogen oxide compressor, and the outlet of the nitrogen oxide compressor is also connected to the exhaust gas turbine.
[0015] Specifically, the outlet of the rapid cooler is also connected to the nitrogen oxide absorption pipe.
[0016] Compared with the prior art, the present invention has the following beneficial technical effects:
[0017] (I) Compared with the prior art, the device of this utility model adds a first demineralized water heater and a second demineralized water heater. It recovers and utilizes the heat from nitrogen oxides through demineralized water, reducing the amount of circulating water used. At the same time, the temperature of the demineralized water obtained after recovering and utilizing the heat from nitrogen oxides is increased, that is, the temperature of the demineralized water entering the steam drum is increased, thereby reducing the amount of steam used in the steam drum. Although it increases the equipment and corresponding piping material costs of two demineralized water heaters, it will be beneficial in the long-term operation of the production enterprise.
[0018] (II) In the device of this utility model, the demineralized water enters the steam drum through the first demineralized water heater, the second demineralized water heater and the demineralized water preheater, thereby increasing the temperature of the demineralized water and reducing the steam consumption of the steam drum.
[0019] (III) The device of this utility model not only reduces the amount of circulating water during the cooling of nitrogen oxide coolers and rapid coolers by recovering heat from demineralized water, but also increases the temperature of demineralized water entering the steam drum and reduces the amount of steam used in the steam drum. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the device in this utility model.
[0021] The labels in the diagram represent the following: 1-Demineralized water preheater, 2-Second demineralized water heater, 3-NOx cooler, 4-NOx compressor, 5-First demineralized water heater, 6-Rapid cooler, 7-Demineralized water feed pump from boiler, 8-Waste heat boiler, 9-Tail gas preheater, 10-Steam drum, 11-Steam exiting the boundary zone external pipe, 12-NOx exiting the boundary zone external pipe, 13-Scrubber, 14-Tail gas turbine, 15-NOx exiting the absorption pipe, 16-Pipeline.
[0022] 801 - High-temperature material inlet for boiler tubes; 802 - Low-temperature material outlet for boiler tubes; 803 - Downcomer interface for boiler shell side; 804 - Riser interface for boiler shell side.
[0023] 1001 - Steam drum feedwater inlet, 1002 - Steam drum downcomer interface, 1003 - Steam drum riser interface, 1004 - Steam drum steam outlet.
[0024] The specific content of this utility model will be further explained in detail below with reference to the embodiments. Detailed Implementation
[0025] It should be noted that, unless otherwise specified, all equipment, instruments, and components in this utility model are based on existing technologies. For example, the waste heat boiler is a known waste heat boiler, the steam drum is a known steam drum, and the second demineralized water heater is a known demineralized water heater.
[0026] In this invention, the outlet end of the steam de-boundary pipe 11 is also connected to the steam de-boundary area; the steam de-boundary area refers to the steam transported from the boundary (boundary area) of the current process unit or plant to the external user or public utility network through a pipeline.
[0027] In this invention, the inlet end of the nitrogen oxide self-boundary pipe 12 is also connected to the nitrogen oxide self-boundary zone; nitrogen oxide self-boundary zone outside refers to nitrogen oxide gas entering the current process unit from outside the system (such as upstream equipment or exhaust gas emission source) through pipes or exhaust gas interfaces for processing or utilization.
[0028] In this invention, the outlet end of the nitrogen oxide absorption tube 15 is connected to the downstream device for nitric acid recovery, and the downstream device for nitric acid recovery adopts a commonly used downstream device for nitric acid recovery known in the art.
[0029] In this invention, the various devices are mainly connected by pipes 16. Each pipe 16 is equipped with a valve as needed, which is opened or closed according to process requirements. All valves in this invention are commonly used valves in the prior art.
[0030] Following the above technical solution, the following are specific embodiments of this utility model. It should be noted that this utility model is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solution of this application fall within the protection scope of this utility model.
[0031] Example:
[0032] This embodiment provides an energy-saving device for nitric acid recovery, such as... Figure 1 As shown, it includes a demineralized water preheater 1, the outlet of which is connected to the inlet of a second demineralized water heater 2, and the outlet of the second demineralized water heater 2 is connected to the inlet of a nitrogen oxide cooler 3.
[0033] like Figure 1 As shown, it also includes a nitrogen oxide compressor 4, the outlet of which is connected to the inlet of the first demineralized water heater 5, and the outlet of the first demineralized water heater 5 is connected to the inlet of the rapid cooler 6.
[0034] like Figure 1 As shown, it also includes a demineralized water boiler feed pump 7. The outlet of the demineralized water boiler feed pump 7 is also connected to the inlet of the first demineralized water heater 5. The outlet of the first demineralized water heater 5 is also connected to the inlet of the second demineralized water heater 2. The outlet of the second demineralized water heater 2 is also connected to the inlet of the demineralized water preheater 1.
[0035] As a preferred embodiment of this invention, such as Figure 1 As shown, it also includes a waste heat boiler 8, the boiler tube side low temperature material outlet 802 of the waste heat boiler 8 is connected to the feed inlet of the tail gas preheater 9, and the discharge outlet of the tail gas preheater 9 is connected to the feed inlet of the demineralized water preheater 1.
[0036] As a preferred embodiment of this invention, such as Figure 1As shown, the outlet of the demineralized water preheater 1 is also connected to the steam drum feedwater inlet 1001 of the steam drum 10, the steam drum downcomer interface 1002 of the steam drum 10 is also connected to the boiler shell downcomer interface 803 of the waste heat boiler 8, the boiler shell riser interface 804 of the waste heat boiler 8 is also connected to the steam drum riser interface 1003 of the steam drum 10, and the steam drum steam outlet 1004 of the steam drum 10 is also connected to the steam demarcation zone outer pipe 11.
[0037] As a preferred embodiment of this invention, such as Figure 1 As shown, the high-temperature material inlet 801 of the boiler tube side of the waste heat boiler 8 is also connected to the nitrogen oxide self-bound zone outer pipe 12.
[0038] As a preferred embodiment of this invention, such as Figure 1 As shown, the outlet of the nitrogen oxide cooler 3 is also connected to the inlet of the scrubbing tower 13, the outlet of the scrubbing tower 13 is also connected to the inlet of the nitrogen oxide compressor 4, and the outlet of the nitrogen oxide compressor 4 is also connected to the exhaust gas turbine 14.
[0039] As a preferred embodiment of this invention, such as Figure 1 As shown, the outlet of the rapid cooler 6 is also connected to the nitrogen oxide absorption pipe 15.
[0040] In this embodiment, by adding a second demineralized water heater 2 to the energy-saving device for nitric acid recovery, the heat from the higher-temperature nitrogen oxides is recovered, reducing the amount of circulating water used in the subsequent nitrogen oxide cooler 3; by adding a first demineralized water heater 5, the heat from the high-temperature nitrogen oxides is recovered, reducing the amount of circulating water used in the rapid cooler 6.
[0041] The device operation process in this embodiment is as follows: High-temperature nitrogen oxide gas enters the high-temperature material inlet 801 of the boiler tube side of the waste heat boiler 8 through the nitrogen oxide self-boundary external pipe 12 to recover heat, and then enters the tail gas preheater 9 and the demineralized water preheater 1 in sequence to continue to recover heat. After a large amount of heat is recovered, it enters the second demineralized water heater 2 to heat the demineralized water, and then enters the nitrogen oxide cooler 3 to cool. The nitrogen oxides cooled to room temperature enter the scrubbing tower 13 to remove impurities, and then enter the nitrogen oxide compressor 4. The high-temperature nitrogen oxide gas discharged from the outlet of the nitrogen oxide compressor 4 enters the first demineralized water heater 5 to recover heat, and then enters the rapid cooler 6 to cool. After cooling, it enters the absorption section through the nitrogen oxide absorption pipe 15 and is absorbed using commonly used devices in the prior art.
[0042] The demineralized water is pumped from the boiler feedwater pump 7 through the first demineralized water heater 5, the second demineralized water heater 2, and the demineralized water preheater 1 before entering the steam drum feedwater inlet 1001 of the steam drum 10.
Claims
1. An energy-saving device for nitric acid recovery, comprising a demineralized water preheater (1), characterized in that, The outlet of the demineralized water preheater (1) is connected to the inlet of the second demineralized water heater (2), and the outlet of the second demineralized water heater (2) is connected to the inlet of the nitrogen oxide cooler (3). It also includes a nitrogen oxide compressor (4), the outlet of which is connected to the inlet of the first demineralized water heater (5), and the outlet of the first demineralized water heater (5) is connected to the inlet of the rapid cooler (6). It also includes a demineralized water boiler feed pump (7), the outlet of which is connected to the inlet of the first demineralized water heater (5), the outlet of the first demineralized water heater (5) is connected to the inlet of the second demineralized water heater (2), and the outlet of the second demineralized water heater (2) is connected to the inlet of the demineralized water preheater (1).
2. The energy-saving device for nitric acid recovery as described in claim 1, characterized in that, It also includes a waste heat boiler (8), wherein the boiler tube low-temperature material outlet (802) of the waste heat boiler (8) is connected to the feed inlet of the tail gas preheater (9), and the discharge outlet of the tail gas preheater (9) is connected to the feed inlet of the demineralized water preheater (1).
3. The energy-saving device for nitric acid recovery as described in claim 2, characterized in that, The outlet of the demineralized water preheater (1) is also connected to the steam drum feed water inlet (1001) of the steam drum (10), the steam drum downcomer interface (1002) of the steam drum (10) is also connected to the boiler shell downcomer interface (803) of the waste heat boiler (8), the boiler shell riser interface (804) of the waste heat boiler (8) is also connected to the steam drum riser interface (1003) of the steam drum (10), and the steam drum steam outlet (1004) of the steam drum (10) is also connected to the steam demarcation zone outer pipe (11).
4. The energy-saving device for nitric acid recovery as described in claim 3, characterized in that, The high-temperature material inlet (801) of the boiler tube side of the waste heat boiler (8) is also connected to the nitrogen oxide self-boundary outer pipe (12).
5. The energy-saving device for nitric acid recovery as described in claim 1, characterized in that, The outlet of the nitrogen oxide cooler (3) is also connected to the inlet of the scrubbing tower (13), the outlet of the scrubbing tower (13) is also connected to the inlet of the nitrogen oxide compressor (4), and the outlet of the nitrogen oxide compressor (4) is also connected to the exhaust gas turbine (14).
6. The energy-saving device for nitric acid recovery as described in claim 1, characterized in that, The outlet of the rapid cooler (6) is also connected to the nitrogen oxide absorption pipe (15).