Waste gas waste heat recovery system

Abstract

The utility model discloses a waste gas waste heat recovery system which comprises a waste gas incinerator, a high-temperature induced draft fan and a flue gas pipeline, one end of the flue gas pipeline is connected with an outlet of the waste gas incinerator, the other end of the flue gas pipeline is connected with the high-temperature induced draft fan, and a valve is arranged on the flue gas pipeline. The heater is connected to an outlet of the high-temperature induced draft fan and is used for heating the tail gas; the urea solution pyrolysis chamber is connected with the heater and is used for pyrolyzing urea into gasified urea; the denitration reactor is connected with a pyrolysis gas outlet of the urea solution pyrolysis chamber through a pipeline and is used for reducing nitrogen oxide in gasified urea after pyrolysis. The utility model has the following advantages: on one hand, the temperature of the high-temperature tail gas generated after the combustion of the waste gas furnace is about 300 DEG C, the electric heating energy can be saved, and on the other hand, the oxygen content of the combusted tail gas is lower than the oxygen content of air, so that the oxygen content of the whole system can be reduced after the tail gas enters the denitration device, and the tail gas emission compliance of the whole system is improved.

Description

Technical Field

[0001] This utility model relates to the field of waste gas treatment technology, and in particular to a waste gas waste heat recovery system. Background Technology

[0002] The description in this section provides only background information related to the disclosure of this utility model and does not constitute prior art.

[0003] Currently, urea pyrolysis uses an electric heater to heat ambient air at 25°C to 350°C to 400°C to pyrolyze the urea before it enters the denitrification system. This process results in high annual energy consumption and low denitrification efficiency.

[0004] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this utility model and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this utility model. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a waste gas waste heat recovery system that addresses the shortcomings of the existing technology. This system utilizes the high-temperature exhaust gas emitted from the waste gas incinerator and recirculates it back for urea pyrolysis, thereby saving energy consumption and reducing the oxygen content inside the denitrification system to improve the efficiency of the denitrification system.

[0006] This application discloses a waste heat recovery system for exhaust gas, comprising:

[0007] The system includes an exhaust gas incinerator, a high-temperature induced draft fan, and a flue gas duct. One end of the flue gas duct is connected to the outlet of the exhaust gas incinerator, and the other end of the flue gas duct is connected to the high-temperature induced draft fan. A valve is installed on the flue gas duct.

[0008] A heater is connected to the outlet of the high-temperature induced draft fan to heat the exhaust gas;

[0009] A urea solution pyrolysis chamber, connected to the heater, is used to pyrolyze urea into vaporized urea;

[0010] The denitrification reactor is connected to the pyrolysis gas outlet of the urea solution pyrolysis chamber via a pipeline, and is used to reduce nitrogen oxides in the gasified urea after pyrolysis.

[0011] Furthermore, in the aforementioned waste heat recovery system, the pyrolysis gas outlet of the urea solution pyrolysis chamber is equipped with a test fixture, on which a test piece capable of monitoring the degree of crystallization is mounted.

[0012] Furthermore, in the aforementioned waste gas waste heat recovery system, the exhaust gas temperature at the outlet of the waste gas incinerator is 300℃~330℃.

[0013] Furthermore, in the aforementioned waste heat recovery system, the flow rate of the high-temperature induced draft fan is 200 m³ / h. 3 / h~300m 3 / h, pressure head is 3000pa.

[0014] Furthermore, in the aforementioned waste heat recovery system, the heating temperature of the heater is 450°C.

[0015] Furthermore, in the aforementioned waste heat recovery system, the purity of the urea solution in the urea solution pyrolysis chamber is 32.5%.

[0016] In summary, the structure adopted in this embodiment of the present invention has the following advantages:

[0017] The waste heat recovery system described in this utility model utilizes the high-temperature exhaust gas emitted from the waste gas incinerator and recirculates it for urea pyrolysis. The oxygen content of the exhaust gas after combustion is lower than that of air. After entering the denitrification device, it helps to reduce the oxygen content of the entire system and improve the compliance of the exhaust gas emission of the entire system; it also saves energy consumption and reduces the oxygen content inside the denitrification system, thereby improving the efficiency of the denitrification system.

[0018] To further understand the features and technical content of this utility model, please refer to the following detailed description and drawings of this utility model. However, the drawings provided are for reference and illustration only and are not intended to limit this utility model. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the tool setting device in an embodiment of this utility model.

[0021] The reference numerals in the above figures are as follows: 1. Waste gas incinerator; 2. High-temperature induced draft fan; 3. Flue gas duct; 4. Valve; 5. Heater; 6. Urea solution pyrolysis chamber; 7. Denitrification reactor. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification.

[0023] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can understand the advantages and effects of this utility model from the content disclosed in this specification. This utility model can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of this utility model. Furthermore, the accompanying drawings of this utility model are for simple illustration only and are not depictions of actual dimensions, as stated in advance. The following embodiments will further describe the relevant technical content of this utility model in detail, but the disclosed content is not intended to limit the scope of protection of this utility model.

[0024] It should be understood that while terms such as "first," "second," and "third" may be used in this document to describe various components or signals, these components or signals should not be limited by these terms. These terms are primarily used to distinguish one component from another, or one signal from another. Furthermore, the term "or" as used herein should, as appropriate, include any combination of one or more of the related listed items.

[0025] Reference Figure 1 As shown in the figure, this application discloses a waste heat recovery system for exhaust gas, including:

[0026] The waste gas incinerator, the high-temperature induced draft fan 2, and the flue gas duct 3 are provided. One end of the flue gas duct 3 is connected to the outlet of the waste gas incinerator, and the other end of the flue gas duct 3 is connected to the high-temperature induced draft fan 2. Multiple valves 4 are provided on the flue gas duct 3.

[0027] Heater 5 is connected to the outlet of the high-temperature induced draft fan 2 to heat the exhaust gas;

[0028] The urea solution pyrolysis chamber 6 is connected to the heater 5 and is used to pyrolyze urea into vaporized urea.

[0029] The denitrification reactor 7 is connected to the pyrolysis gas outlet of the urea solution pyrolysis chamber 6 via a pipeline, and is used to reduce nitrogen oxides in the gasified urea after pyrolysis.

[0030] The high-temperature induced draft fan is supplied in a skid-mounted modular configuration, with two sets installed, one for operation and one as backup. A high-pressure fan is used to overcome resistance from pipes and electric heaters. Flue gas duct 3 requires insulation, with an estimated thickness of 200mm. Aluminum insulation material is used to prevent heat loss.

[0031] Specifically, in this embodiment, the pyrolysis gas outlet of the urea solution pyrolysis chamber 6 is equipped with a test fixture (not shown in the figure), on which a test piece capable of monitoring the degree of crystallization is mounted. The test fixture is used to periodically disassemble and observe the pyrolysis effect of urea; by replacing the test piece, the degree of crystallization under different environments can be observed.

[0032] Specifically, in this embodiment, the exhaust gas temperature at the outlet of the waste gas incinerator 1 is 300℃~330℃.

[0033] Specifically, in this embodiment, the flow rate of the high-temperature induced draft fan 2 is 200m³ / s. 3 / h~300m 3 / h, pressure head is 3000pa.

[0034] Specifically, in this embodiment, the heating temperature of the heater 5 is 450°C.

[0035] Specifically, in this embodiment, the purity of the urea solution in the urea solution pyrolysis chamber 6 is 32.5%, which increases the purity of urea and lowers the pyrolysis temperature.

[0036] By using the above structure, the gas source is changed from air to high-temperature exhaust gas from the waste gas incinerator. On the one hand, the exhaust gas temperature is around 300℃, which saves energy for electric heating. On the other hand, the oxygen content of the exhaust gas after combustion is lower than that of air, which helps to reduce the oxygen content of the entire system after entering the denitrification device, improving the compliance of the entire system's exhaust gas emissions. The high-temperature exhaust gas discharged from the waste gas incinerator has a temperature of 300℃~330℃. The waste heat exhaust gas is heated to 450℃ in a heater and then recirculated for urea pyrolysis. After urea pyrolysis, the gasified urea enters the SCR system to reduce nitrogen oxides, thereby saving energy consumption and reducing the oxygen content inside the denitrification system. The advantages of this embodiment for improving the efficiency of the denitrification system are as follows: 1. Energy saving: Calculated annual energy saving of 78,000 kWh, equivalent to RMB 57,000; 2. No impact on the normal operation of existing denitrification equipment, while reducing the oxygen content of the system, improving denitrification efficiency, and reducing the emission conversion rate; 3. Budget price of RMB 86,000 (including tax), after tax, the price is RMB 76,000, including the second stage cost, the overall removal of the electric heater test, and the estimated recovery efficiency of about 1 year to 1 year and 3 months; 4. The second step improves the purity of urea, lowers the pyrolysis temperature, and stops using the heater, ultimately achieving the final energy-saving plan, eliminating the need for electric heating, saving RMB 97,397 annually, and recovering within one year.

[0037] The above-disclosed content is only a preferred and feasible embodiment of the present utility model, and is not intended to limit the scope of the patent application of the present utility model. Therefore, all equivalent technical changes made using the contents of the present utility model specification and drawings are included in the scope of the patent application of the present utility model.

[0038] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0039] Although this application has been described by way of examples, those skilled in the art will know that this application has many modifications and variations without departing from the spirit of this application, and it is intended that the appended embodiments include these modifications and variations without departing from this application.

Claims

1. A waste heat recovery system for exhaust gas, characterized in that, include: The system includes an exhaust gas incinerator, a high-temperature induced draft fan, and a flue gas duct. One end of the flue gas duct is connected to the outlet of the exhaust gas incinerator, and the other end of the flue gas duct is connected to the high-temperature induced draft fan. A valve is installed on the flue gas duct. A heater is connected to the outlet of the high-temperature induced draft fan to heat the exhaust gas; A urea solution pyrolysis chamber, connected to the heater, is used to pyrolyze urea into vaporized urea; The denitrification reactor is connected to the pyrolysis gas outlet of the urea solution pyrolysis chamber via a pipeline, and is used to reduce nitrogen oxides in the gasified urea after pyrolysis.

2. The waste heat recovery system according to claim 1, characterized in that, The pyrolysis gas outlet of the urea solution pyrolysis chamber is equipped with a test fixture, on which a test piece capable of monitoring the degree of crystallization is mounted.

3. The waste heat recovery system according to claim 1, characterized in that, The exhaust gas temperature at the outlet of the waste gas incinerator is 300℃~330℃.

4. The waste heat recovery system according to claim 1, characterized in that, The flow rate of the high-temperature induced draft fan is 200 m³ / s. 3 / h~300m 3 / h, pressure head is 3000pa.

5. The waste heat recovery system according to claim 1, characterized in that, The heating temperature of the heater is 450°C.

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