A kind of pyrolysis furnace urea crystallization after dredging device

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By designing a urea crystallization unblocking device for pyrolysis furnaces, solvent is introduced through a handhole to dissolve and discharge the crystals, solving the problem of blockage at the bottom of the pyrolysis furnace, achieving rapid cleaning and system recovery, and improving the boiler's operational stability and environmental efficiency.

CN224672472UActive Publication Date: 2026-08-25INNER MONGOLIA BAOGANGXIN ENERGY CO LTD

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Patent Information

Application Number: CN202521794564.7
Authority / Receiving Office: CN · China
Patent Type: Utility models(China)
Current Assignee / Owner
Filing Date: 2025-08-21
Publication Date: 2026-08-25
Estimated Expiration: 2035-08-21

AI Technical Summary

Technical Problem

In existing technologies, crystallization blockage at the bottom of the pyrolysis furnace causes the denitrification system to malfunction, resulting in poor pyrolysis performance, low flue gas denitrification efficiency, and difficulty in cleaning, which affects the normal operation of the boiler.

Method used

Design a device for unblocking urea crystallization in a pyrolysis furnace, including a vertical discharge section and a connecting discharge section. Solvent is introduced through a hand hole to dissolve the crystals, and the dissolved crystals are discharged through the hand hole. Alloy materials are used to improve the unblocking effect.

Benefits of technology

The rapid removal of crystals shortened the cleaning time, ensured the denitrification system could resume operation, reduced unit losses, and improved system reliability and the operating efficiency of environmental protection equipment.

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Abstract

The utility model belongs to pyrolysis furnace dredging device technical field, a kind of pyrolysis furnace urea crystallization after dredging device, comprising: vertical discharge part and connecting discharge part, the one end of vertical discharge part and the one end of connecting discharge part synthesis unity with the bottom of pyrolysis furnace, the other end of vertical discharge part is provided with second hand hole, for discharging crystallization dissolved material;The other end of connecting discharge part is communicated ammonia gas pipeline, first hand hole is provided on the lateral wall of connecting discharge part, for discharging crystallization dissolved material;The lateral wall of pyrolysis furnace is provided with third hand hole, for inputting solvent.The above-mentioned dredging device is used for quickly removing solid crystallization in pyrolysis furnace, when finding that boiler denitration system pyrolysis furnace occurs crystallization blockage, after shutdown, solvent is input by third hand hole, crystallization is quickly removed, crystallization dissolved material is discharged through first hand hole and second hand hole, effectively shorten the time of cleaning crystallization, so that the denitration system of unit reaches recovery as soon as possible.Guarantee environmental protection equipment facility operation.

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Description

Technical Field

[0001] The utility model belongs to the technical field of pyrolysis furnace dredging devices, and particularly relates to a dredging device after urea crystallization in a pyrolysis furnace. Background Art

[0002] At present, in the denitration system supporting boiler equipment in the prior art, the technology of urea pyrolysis is adopted. The urea solution is sprayed into the pyrolysis furnace through a spray gun installed in the pyrolysis furnace. Under the heating of the high-temperature air pressure in the pyrolysis furnace, the urea solution decomposes into ammonia gas. The high-temperature air pressure blows the decomposed ammonia gas to the bottom of the pyrolysis furnace. The ammonia gas coming out from the bottom of the pyrolysis furnace is sprayed into the ammonia injection grid arranged in the boiler furnace through the ammonia injection branch pipe. The ammonia gas realizes the denitration function of the flue gas under the catalytic action of the flue gas flow and the arrangement in the furnace.

[0003] The prior art has the following defects and deficiencies: Since the unit load changes with the change of blast furnace gas fuel, when the load is low, the pyrolysis effect is poor, and crystalline solids will appear at the bottom of the pyrolysis furnace, resulting in the inability of the denitration system pyrolysis furnace to operate normally. When the bottom of the pyrolysis furnace is blocked, the air volume in the pyrolysis furnace will decrease significantly, the pyrolysis effect is poor, the flue gas denitration efficiency is low, and the denitration at the boiler outlet cannot meet the standard emission, which is a serious problem. It is necessary to stop the machine for maintenance and dredging. Due to the high temperature and the pungent smell of ammonia gas, the dredging has increased the difficulty. Content of the Utility Model

[0004] The utility model provides a dredging device after urea crystallization in a pyrolysis furnace, which solves the problem of quickly cleaning the crystalline substances.

[0005] To achieve the above object, the present application provides the following technical solutions:

[0006] A dredging device after urea crystallization in a pyrolysis furnace includes: a vertical discharge part and a connecting discharge part. One end of the vertical discharge part and one end of the connecting discharge part are integrated and communicate with the bottom of the pyrolysis furnace. The other end of the connecting discharge part communicates with the ammonia pipeline. A first manhole is provided on the side wall of the connecting discharge part for discharging the crystalline dissolved substances; a second manhole is provided at the other end of the vertical discharge part for discharging the crystalline dissolved substances; a third manhole is provided on the side wall of the pyrolysis furnace for inputting a solvent for dissolving the solid crystalline urea substances.

[0007] Further, in the above-mentioned dredging device, the connecting discharge part includes an arc section and a straight section. One end of the arc section and one end of the vertical discharge part are integrated and communicate with the bottom of the pyrolysis furnace. The other end of the arc section communicates with one end of the straight section. The arc section protrudes towards the straight section. The other end of the straight section communicates with the ammonia pipeline.

[0008] Further, in the above-mentioned dredging device, a first manhole is provided on the side wall of the straight section of the connecting discharge part.

[0009] Furthermore, in the aforementioned unblocking device, the unblocking device is made of alloy material.

[0010] Furthermore, in the aforementioned unblocking device, one end of the unblocking device is connected to the bottom of the pyrolysis furnace via a flange, and the other end of the unblocking device is connected to an ammonia gas pipeline.

[0011] Furthermore, in the aforementioned unblocking device, the cross-sectional area of the vertical discharge section is the same as the cross-sectional area of the bottom of the pyrolysis furnace.

[0012] Furthermore, in the aforementioned unblocking device, an endoscope is provided at the other end of the vertical discharge section for observing the condition of the crystals.

[0013] The technical solution provided in this application has the following beneficial effects:

[0014] This utility model patent relates to a device for clearing urea crystallization in a pyrolysis furnace. When crystallization blockage is detected in the pyrolysis furnace of the boiler denitrification system, after shutdown, solvent is introduced through the third manhole to quickly remove the crystals, and the dissolved crystals are discharged through the first and second manholes. This effectively shortens the time for clearing crystals and allows the unit's denitrification system to recover as quickly as possible, ensuring the operation of environmental protection equipment and facilities. Attached Figure Description

[0015] Figure 1 A schematic diagram of a dredging device for urea crystallization in a pyrolysis furnace provided in this application;

[0016] The attached diagrams are labeled as follows: pyrolysis furnace 1, first hand hole 11, second hand hole 12, third hand hole 13, bottom of pyrolysis furnace 15, spray gun 16. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0018] In the description of this utility model, it should be noted that the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "both ends," "one end," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," and "connected," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0020] See attached document Figure 1 This application provides a detailed description of a device for clearing blockages after urea crystallization in a pyrolysis furnace, as provided in an embodiment. Figure 1 This is a schematic diagram of a device for clearing blockages after urea crystallization in a pyrolysis furnace, as provided in this application.

[0021] like Figure 1 As shown, this application provides a device for clearing urea crystallization in a pyrolysis furnace, comprising: a vertical discharge section and a connecting discharge section. One end of the vertical discharge section and one end of the connecting discharge section are integrated and communicate with the bottom 15 of the pyrolysis furnace. The other end of the vertical discharge section is provided with a second handhole 12 for discharging the crystallized dissolved material. The other end of the connecting discharge section is connected to an ammonia gas pipeline. The side wall of the connecting discharge section is provided with a first handhole 11 for discharging the crystallized dissolved material. The side wall of the pyrolysis furnace 1 is provided with a third handhole 13 for inputting solvent.

[0022] This utility model patent relates to a device for clearing urea crystallization in a pyrolysis furnace. It is used to quickly remove solid crystals from the pyrolysis furnace. When crystallization blockage is detected in the pyrolysis furnace 1 of the boiler denitrification system, after shutdown, solvent is introduced through the third handhole 13 to quickly remove the crystals. The dissolved crystals are discharged through the first handhole 11 and the second handhole 12, effectively shortening the time for clearing crystals and enabling the unit's denitrification system to recover as quickly as possible. This ensures the operation of environmental protection equipment and facilities.

[0023] like Figure 1As shown, this application provides a device for clearing urea crystallization in a pyrolysis furnace. This device has a tubular structure, functioning as a pipe, with input at the top and discharge at the bottom or right side. It is used to quickly remove all solid crystals from the pyrolysis furnace. Specifically, the device discharges solid crystals and dissolved crystals through output ports (i.e., a first and a second manhole) within the pipe. The device is installed at the bottom 15 of the pyrolysis furnace via a flange and is connected to the furnace. The bottom 15 of the pyrolysis furnace has a constricted structure with a gradually decreasing cross-sectional area from top to bottom, facilitating butt welding with the pipe. In one specific embodiment, the constricted structure is an inverted cone. A spray gun 16 is installed inside the pyrolysis furnace 1 for inputting urea solution.

[0024] like Figure 1 As shown, the unblocking device is connected to the bottom 15 of the pyrolysis furnace at one end via a flange, and to an ammonia gas pipeline at the other end. The device includes a vertical discharge section and a connecting discharge section, with the vertical discharge section being a vertical pipe. One end of the vertical discharge section and one end of the connecting discharge section are integrated and connected to the bottom 15 of the pyrolysis furnace via a flange. The vertical discharge section is cylindrical, facilitating the direct discharge of dissolved crystals and crystals. One end (upper end) of the vertical discharge section is the input, and the other end (lower end) is the output. One end of the vertical discharge section is installed at the bottom of the pyrolysis furnace, extending downwards from the bottom 15 to facilitate the discharge of dissolved crystals. Specifically, a second handhole 12 is provided at the other end of the vertical discharge section for discharging dissolved crystals and also facilitating the discharge of crystals. An endoscope can be installed at the other end of the vertical discharge section, allowing observation of the crystals inside the pyrolysis furnace 1 and facilitating cleaning of the crystals at that location. Preferably, the cross-sectional area of the second handhole 12 is equal to the cross-sectional area of the vertical discharge section, further facilitating the discharge of dissolved crystals. The cross-sectional area of the vertical discharge section can be the same as or smaller than the cross-sectional area of the bottom 15 of the pyrolysis furnace, depending on the welding requirements. Preferably, the cross-sectional area of the vertical discharge section is the same as the cross-sectional area of the bottom 15 of the pyrolysis furnace, which facilitates the discharge of crystalline dissolved substances (which may also include crystals) in the pyrolysis furnace 1.

[0025] The two ends of the discharge section are connected to the pyrolysis furnace 1 and the ammonia pipeline respectively via flanges. The discharge section facilitates construction by operators, who can use tools such as steel chisels to clean up dissolved crystals and crystalline substances. In the front view, one end (top) of the discharge section is the input, and the other end (right side) is the output. The discharge section includes an arc-shaped section and a straight section; the arc-shaped section is an arc-shaped pipe, and the straight section is a straight pipe. One end (top) of the arc-shaped section is the input, and the other end (right side) is the output. One end of the arc-shaped section and one end of the vertical discharge section are integrated and connected to the bottom 15 of the pyrolysis furnace via a flange. The other end of the arc-shaped section is connected to the straight section via a flange. At one end, the center of the arc-shaped section is in a direction away from the straight section, meaning the arc-shaped section protrudes towards the straight section. This arc-shaped section changes the output direction of the unblocking device, facilitating cleaning by operators. The straight section has an input at one end (left) and an output at the other end (right). One end of the straight section connects to the arc-shaped section, and the other end connects to an ammonia pipeline via a flange. A first handhole 11 is provided on the side wall of the straight section connecting to the discharge section for discharging the dissolved crystals. The first handhole 11 on the side wall of the straight section facilitates operation with tools such as steel rods. During operation, the temperature of the pyrolysis furnace 1 is above 420℃, and water will not accumulate in the first handhole 11. A third handhole 13 is provided on the side wall of the pyrolysis furnace 1 for inputting solvent (mainly high-temperature solvent). This solvent is low-pressure steam or hot water, used to dissolve the crystals. Preferably, the third handhole 13 is located on the side wall near the bottom of the pyrolysis furnace for easy dissolution of the crystals.

[0026] The unblocking device is made of alloy material, which is highly rigid and has a good unblocking effect. It should be noted that when pyrolysis furnace 1 malfunctions or the flue gas temperature is lower than 380℃, the urea solution sprayed into the pyrolysis furnace 1 by the spray gun 16 will not be completely decomposed into ammonia. This undecomposed urea solution will form solid urea crystals at the bottom 15 of the pyrolysis furnace. When a large amount of solid urea crystals are produced, they will accumulate at the bottom 15 of the pyrolysis furnace, causing blockage. Cleaning is required; otherwise, the blockage at the bottom 15 of the pyrolysis furnace will prevent ammonia from being discharged into the ammonia injection grid of the boiler, forcing a shutdown for treatment. Due to the high hardness of solid urea crystals, cleaning is difficult and usually takes more than 24 hours, resulting in significant losses for the company due to the shutdown time.

[0027] When crystals appear during use, quickly stop the machine for maintenance, open the first handhole 11, the second handhole 12, and then the third handhole 13. Spray high-temperature solvent through the third handhole 13 onto the crystals at the bottom of the pyrolysis furnace to flush the bottom of the furnace. The crystals will quickly dissolve and drain out through the first handhole 11 and the second handhole 12, thus quickly clearing the pyrolysis furnace 1 and allowing the system to resume operation in a short time, greatly shortening the maintenance time of the pyrolysis furnace 1. During cleaning, the dissolved crystals and crystals are easily discharged from the first handhole 11. However, since the crystals (urea) form hard solids after crystallization, they will completely block the lower outlet of the pyrolysis furnace 1 (around the second handhole 12). At this time, the second handhole 12 can be opened for cleaning, and an endoscope can be used through the second handhole 12 to observe whether the pyrolysis furnace 1 is clean. In other words, the first handhole 11 and the second handhole 12 are set up and used in combination to significantly improve the effect of removing crystals. After quickly clearing the bottom of the pyrolysis furnace using the above method, start the system, and the pyrolysis furnace 1 can start up quickly.

[0028] In one specific embodiment, the main equipment supporting the pyrolysis furnace system of a certain factory is a 165MW generator set, with an actual average hourly power generation of 160MW. At an electricity price of 0.40 yuan / kWh, installing this utility model saves 1 hour of time compared to not using it. The comprehensive calculation is: 160MW × 0.4 yuan / kWh × 1 = 64,000 yuan. This roughly estimates a benefit of 64,000 yuan. It also shortens unblocking time and reduces unit losses. During the operation of the No. 5 and No. 6 gas-steam combined cycle generator sets, the factory experienced multiple blockages in the ammonia injection branch pipes. Due to the use of the unblocking device provided by this utility model for urea crystallization in the pyrolysis furnace, maintenance time was saved, and a rough estimate suggests a benefit of 64,000 yuan.

[0029] This utility model can be applied in pyrolysis furnaces of similar boiler denitrification systems. According to industry knowledge, this product can be installed in pyrolysis furnaces of other power plants or chemical plants that use urea and ammonia nitrogen compounds as media for denitrification treatment. When the pyrolysis furnace is blocked by crystallization, this product can ensure the effectiveness of unblocking and shorten the maintenance time of environmental protection equipment. It has the potential for promotion and expansion.

[0030] For those skilled in the art, this invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. It is obvious that this invention is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, all embodiments are merely illustrative and not exhaustive, and should be considered exemplary and non-limiting. The scope of this invention is defined by the appended claims rather than the foregoing description, and therefore all changes falling within the meaning and scope of equivalents of the claims are intended to be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims. All changes within the scope of this invention or its equivalents are included in this invention.

Claims

1. A device for clearing blockages after urea crystallization in a pyrolysis furnace, characterized in that, include: Vertical discharge section and connecting discharge section, One end of the vertical discharge section and one end of the connecting discharge section are integrated and communicate with the bottom of the pyrolysis furnace. The other end of the connecting discharge section is connected to an ammonia gas pipeline. A first hand hole is provided on the side wall of the connecting discharge section for discharging the crystalline dissolved product. A second hand hole is provided on the other end of the vertical discharge section for discharging the crystalline dissolved product. A third hand hole is provided on the side wall of the pyrolysis furnace for inputting the solvent for dissolving the solid urea crystals.

2. The unblocking device according to claim 1, characterized in that, The connecting discharge section includes an arc-shaped section and a straight section. One end of the arc-shaped section and one end of the vertical discharge section are integrated and connected to the bottom of the pyrolysis furnace. The other end of the arc-shaped section is connected to one end of the straight section. The arc-shaped section protrudes into the straight section. The other end of the straight section is connected to an ammonia gas pipeline.

3. The unblocking device according to claim 2, characterized in that, A first hand hole is provided on the side wall of the straight section connecting the discharge part.

4. The unblocking device according to claim 1, characterized in that, The unblocking device is made of alloy material.

5. The unblocking device according to claim 1, characterized in that, One end of the unblocking device is connected to the bottom of the pyrolysis furnace via a flange, and the other end of the unblocking device is connected to an ammonia pipeline.

6. The unblocking device according to claim 1, characterized in that, The cross-sectional area of the vertical discharge section is the same as the cross-sectional area of the bottom of the pyrolysis furnace.

7. The unblocking device according to claim 1, characterized in that, An endoscope is installed at the other end of the vertical discharge section for observing the condition of the crystals.