Pipeline defect cooling treatment device for urea ammonia production system and temperature difference driving method

Abstract

The invention relates to a urea-to-ammonia system pipeline defect cooling treatment device which comprises a to-be-cooled pipeline and an inner leakage valve and further comprises a cylindrical tank, the cylindrical tank comprises two semi-cylindrical shells, and the two semi-cylindrical shells are arranged in an opening and closing mode through hinges; lock holes are formed in the centers of the top and the bottom of the cylindrical tank, and the surfaces of the lock holes are attached to the outer wall of a pipeline needing to be cooled. A pushing plate structure is arranged in the semi-cylindrical shell; a filling hole is further formed in the top of the cylindrical tank, a sealing cover is mounted at the top of the filling hole, and the filling hole is used for filling dry ice into the cylindrical tank, so that defect treatment can be carried out under the condition that the system is not completely stopped.

Description

Technical Field

[0001] The invention relates to a pipeline defect cooling processing device for a urea-ammonia production system and a temperature difference driving method, belonging to the technical field of pipeline defect cooling. Background Art

[0002] The process of producing ammonia by urea hydrolysis in thermal power plants is safer than that of producing ammonia by liquid ammonia. However, the chemical reaction process of urea hydrolysis is complicated and will produce more corrosive intermediates, which will corrode ammonia pipelines and valves. When dealing with defects in ammonia pipelines, the system may be temporarily unable to shut down;

[0003] At present, such defects are processed online with local pressure. During the processing, the operator wears positive pressure respirators and other safety protection equipment to deal with the defects, or shut down the system, which will cause huge economic losses to the enterprise. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a pipeline defect cooling treatment device and a temperature difference driving method for a urea ammonia production system, which can perform defect treatment without completely shutting down the system.

[0005] The technical solution of the present invention is as follows:

[0006] A cooling treatment device for pipeline defects in a urea-ammonia production system comprises a pipeline to be cooled and an internal leakage valve, and also comprises a cylindrical tank, wherein the cylindrical tank comprises two semi-cylindrical shells, and the two semi-cylindrical shells are opened and closed by hinges; lock holes are provided at the centers of the top and bottom of the cylindrical tank, and the surfaces of the lock holes are in contact with the outer walls of the pipeline to be cooled; a pushing plate structure is provided inside the semi-cylindrical shells; a pouring hole is also provided on the top of the cylindrical tank, a sealing cover is installed on the top of the pouring hole, and the pouring hole is used to pour dry ice into the cylindrical tank.

[0007] Among them, the pushing plate structure includes an inverted L-shaped displacement plate and an inverted L-shaped elastic silicone plate, the displacement plate and the elastic silicone plate are staggered and connected to form an extrusion surface, the extrusion surface is slidably arranged with the inner bottom wall of the semi-cylindrical shell, a gap is arranged between the outer wall of the extrusion surface and the inner wall of the semi-cylindrical shell, and an electric push rod is arranged between the outer wall of the displacement plate and the inner wall of the semi-cylindrical shell; the displacement plate includes an arc-shaped vertical plate and a horizontal plate arranged at the top of the arc-shaped vertical plate, a vent hole is opened at the top of the horizontal plate, and a docking hole is opened at the top of the semi-cylindrical shell.

[0008] Wherein, a layer of thermal insulation cotton is fitted on the inner wall of the semi-cylindrical shell and the surface of the push plate structure.

[0009] The surface of the lock hole is also fixedly provided with a flexible metal shell, and the space between the flexible metal shell and the surface of the lock hole is filled with electrorheological fluid; an activation device is also included, and the activation device provides an activation signal for the electrorheological fluid.

[0010] Wherein, the docking hole is arranged on the displacement path of the vent hole of the horizontal plate.

[0011] Among them, the thermal insulation cotton is 5cm, and the distance between the displacement plate and the pipeline to be cooled and the internal leakage valve is not less than 20cm.

[0012] Wherein, a carbon dioxide gas sensor is arranged inside the cylindrical tank, and the carbon dioxide gas sensor is electrically connected to the electric push rod.

[0013] Wherein, both ends of the extrusion surface are displacement plates.

[0014] Among them, a plurality of slide rails are arranged at the bottom of the cylindrical tank, and a step groove is also opened at the bottom of the slide rail, and the side wall of the step groove is provided with a limiting convex edge; the bottom of the arc-shaped vertical plate is hinged with a warped edge, and the side walls at both ends of the warped edge match the inner wall of the step groove, and the front end of the warped edge abuts against the rear end of the limiting convex edge, and the two sides of the bottom of the arc-shaped vertical plate slide in fit with the slide rail.

[0015] A temperature difference driving method for a temperature sensor, characterized in that it comprises the following steps:

[0016] S1: Set the real-time temperature difference change value to T f ;

[0017] S2: record the temperature changes by time group as T1[1, 2, 3, ...m], T2[1, 2, 3, ...m]......T n [1, 2, 3, ...m], where m is the total number of temperature points measured by the temperature sensor;

[0018] S3: Calculate the average measured temperature at the pth position in the first group of temperature record data: 2 f+1 is the total number of points centered at point p. Point p is the point where the temperature difference rate decreases slowly during recording, indicating that a large amount of dry ice sublimates and releases carbon dioxide. Take the first set of data as an example;

[0019] S4: Calculate the average value of the historical measured temperature at the pth location

[0020] S5: Subtract the historical average value in step 4 from the average value at point p in the nth group to get the temperature difference, that is,

[0021] S6: When T f The temperature is greater than T p The electric push rod can be started.

[0022] The present invention has the following beneficial effects:

[0023] The present invention utilizes the rapid heat absorption of dry ice sublimation, and controls the dry ice dosage and cooling time to rapidly reduce the local pipeline of the urea hydrolysis ammonia production system, so that the urea crystallizes and blocks the medium flow in the ammonia pipeline, thereby creating a window time for local defect treatment of the urea hydrolysis ammonia production system, and the defect treatment can be performed without completely shutting down the system;

[0024] At the same time, the present invention utilizes the characteristics of electrorheological fluid, so that the device can match pipelines of different sizes;

[0025] The present invention also provides a pushing plate structure. Since the temperature of the dry ice is higher on the side close to the pipeline and it is easier to reach a sublimation state, the pushing plate structure is driven to push the remaining dry ice to the side close to the pipeline, which can effectively shorten the cooling time. At the same time, in the process of driving the pushing plate structure to move, the connecting channel between the inside and the outside can also be opened, so that the internal carbon dioxide gas can be discharged outward to avoid explosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the cooling treatment device for pipeline defects in a urea-to-ammonia system of the present invention;

[0027] Figure 2 This is a schematic diagram of the cooling pipeline and the internal leakage valve structure required for the present invention;

[0028] Figure 3 It is a schematic diagram of the displacement plate structure of the present invention. Figure 4 It is a schematic diagram of the slide rail structure of the present invention.

[0029] The reference numerals in the figure represent:

[0030] 1. Pipes to be cooled; 2. Internal leakage valve; 3. Cylindrical tank; 4. Lock hole; 5. Displacement plate; 31. Semi-cylindrical shell; 32. Filling hole; 33. Docking hole; 34. Slide rail; 41. Flexible metal shell; 51. Elastic silicone plate; 52. Extrusion surface; 53. Arc vertical plate; 54. Horizontal plate; 55. Vent hole; 35. Step groove; 36. Limiting convex edge; 56. Warping edge. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] See also Figures 1 to 4 , the invention provides a technical solution:

[0033] A cooling treatment device for pipeline defects in a urea ammonia production system includes a pipeline to be cooled 1 and an internal leakage valve 2. The pipeline to be cooled 1 and the internal leakage valve 2 are structures in the existing urea ammonia production system and will not be described in detail here.

[0034] It also includes a cylindrical tank 3, which includes two semi-cylindrical shells 31. The two semi-cylindrical shells 31 are opened and closed by hinges. The two semi-cylindrical shells 31 are combined to form a cylindrical tank 3 to wrap the pipeline 1 to be cooled and the internal leakage valve 2. The center of the top and bottom of the cylindrical tank 3 is provided with a lock hole 4, and the surface of the lock hole 4 is in contact with the outer wall of the pipeline 1 to be cooled; the top of the cylindrical tank 3 is also provided with a filling hole 32, and a sealing cover is installed on the top of the filling hole 32. The filling hole 32 is used to fill dry ice into the cylindrical tank 3; by filling the filling hole 32, it is ensured that the dry ice is fully in contact with the pipeline, so that the dry ice can fully absorb the heat of the pipeline when sublimating to reduce the temperature of the pipeline; by controlling the amount of dry ice used and the cooling time, the pipeline of the urea hydrolysis ammonia production system is locally rapidly reduced, so that the medium flow in the ammonia pipeline is blocked after the urea crystallizes, and a window time is created for local defect treatment of the urea hydrolysis ammonia production system, so that the system can be defect-treated without being completely shut down;

[0035] A push plate structure is provided inside the semi-cylindrical shell 31. Since the temperature of the dry ice near the pipe is higher and it is easier to sublimate, after the dry ice near the pipe sublimates, the push plate structure is driven to push the remaining dry ice to the pipe, which can effectively shorten the cooling time.

[0036] Specifically, the push plate structure includes an inverted L-shaped displacement plate 5 and an inverted L-shaped elastic silicone plate 51, the displacement plate 5 and the elastic silicone plate 51 are staggered and connected to form an extrusion surface 52, the extrusion surface 52 is slidably arranged with the inner bottom wall of the semi-cylindrical shell 31, a gap is arranged between the outer wall of the extrusion surface 52 and the inner wall of the semi-cylindrical shell 31, and an electric push rod is arranged between the outer wall of the displacement plate 5 and the inner wall of the semi-cylindrical shell 31; a plurality of slide rails 34 are arranged at the bottom of the cylindrical tank 3, and the bottom of the displacement plate 5 is slidably matched with the slide rails 34; as mentioned above, when the dry ice close to one side of the pipeline sublimates, the electric push rod is started to push the displacement plate 5 along the slide rails 34, at this time, the displacement plates 5 arranged at intervals will move synchronously toward the pipeline, and the elastic silicone plate 51 in the middle will be dragged by the moving plate 5 and move synchronously toward the pipeline, and at the same time, due to the characteristics of the elastic silicone plate 51, it will be deformed and will not affect the overall displacement of the extrusion surface 52;

[0037] It is worth mentioning that dry ice will release a large amount of carbon dioxide gas when absorbing heat and sublimating. If the device is too closed, the pressure inside the device will increase or even explode. Therefore, the displacement plate 5 includes an arc-shaped vertical plate 53 and a horizontal plate 54 arranged at the top of the arc-shaped vertical plate 53. A vent 55 is opened on the top of the horizontal plate 54, and a docking hole 33 is opened on the top of the semi-cylindrical shell 31. The docking hole 33 is arranged on the displacement path of the vent 55 of the horizontal plate 54. A carbon dioxide gas sensor or a temperature sensor is arranged inside the cylindrical tank 3. The carbon dioxide gas sensor is electrically connected to the electric push rod. Specifically, when the dry ice inside sublimates and releases carbon dioxide gas, the carbon dioxide gas sensor is arranged near the top of the semi-cylindrical shell 31. On the side near the pipeline, after the carbon dioxide gas sensor senses that the internal carbon dioxide gas has reached a preset value, the signal is used to drive the electric push rod to move, which can push the dry ice to a position closer to the pipeline on the one hand, and on the other hand, it can push the horizontal plate 54 so that the vent hole 55 on the horizontal plate 54 is connected with the docking hole 33 after a certain displacement, thereby forming a hole for releasing the internal gas, releasing the internal carbon dioxide, and avoiding explosion. When the internal carbon dioxide gas has not yet reached the preset value, the docking hole 33 and the vent hole 55 are staggered, that is, the inside is isolated from the outside, which can keep the internal dry ice at a lower temperature for a longer time, shortening the cooling time of the pipeline;

[0038] At the same time, since the gasification of dry ice will produce carbon dioxide, and the carbon dioxide accumulates in the sealed space, it will hinder the advancement of the displacement plate 5 to a certain extent. Therefore, a step groove 35 is provided at the bottom of the slide rail 34, that is, the overall cross-section of the slide rail 34 and the step groove 35 is inverted convex, and the side wall of the step groove 35 is provided with a limiting convex edge 36, the overall length of the limiting convex edge 36 is smaller than the step groove 35, and the limiting convex edge 36 is arranged on the side close to the pipeline 1 to be cooled, that is, there is a gap between the limiting convex edge 36 and the inner wall of the cylindrical tank 3; the bottom of the arc-shaped vertical plate 53 is hinged with a warping edge 56, and the side walls at both ends of the warping edge 56 match the inner wall of the step groove 35. When the arc-shaped vertical plate 53 has not been pushed, the warping edge 56 is located between the limiting convex edge 36 and the inner wall of the cylindrical tank 3, leaving a gap. In the gap, specifically, when the warping edge 56 is located in the gap, it can block the air circulation in the gap between the outer wall of the extrusion surface 52 and the inner wall of the semi-cylindrical shell 31 to a certain extent, the front end of the warping edge 56 abuts against the rear end of the limiting convex edge 36, and the bottom two sides of the arc-shaped vertical plate 53 slide and fit with the slide rail 34; when it is necessary to push the arc-shaped vertical plate 53, the arc-shaped vertical plate 53 moves, and then the warping edge 56 is blocked by the limiting convex edge 36 and warps up, and then the area for dry ice placement and the gap between the outer wall of the extrusion surface 52 and the inner wall of the semi-cylindrical shell 31 are opened, and carbon dioxide can flow through the space between the two and be stored in the gap between the outer wall of the extrusion surface 52 and the inner wall of the semi-cylindrical shell 31. At this time, it will no longer hinder the advancement of the displacement plate 5, and at the same time, it can also reduce the pressure of internal carbon dioxide accumulation.

[0039] A layer of thermal insulation cotton is fitted on the inner wall of the semi-cylindrical shell 31 and the surface of the push plate structure; the thermal insulation cotton is 5 cm, which can ensure that the dry ice is in full contact with the pipeline and reduce the external heat transferred to the inside of the device to reduce the cooling effect of the dry ice on the ammonia vapor.

[0040] A flexible metal shell 41 is also fixedly arranged on the surface of the lock hole 4, and the space between the flexible metal shell 41 and the surface of the lock hole 4 is filled with an electrorheological fluid; an activation device is also included, and the activation device provides an activation signal for the electrorheological fluid; because the diameters of the pipe 1 to be cooled are different in different cases, the flexible metal shell 41 is fixedly arranged on the surface of the lock hole 4, and when facing pipes 1 of different sizes to be cooled, the flexible metal shell 41 will be squeezed and deformed, and at the same time, it will fit the pipe 1 to be cooled more closely, and then the internal electrorheological fluid is activated by the activation device, so that the internal electrorheological fluid is converted into a solid state, so that the flexible metal shell 41 will no longer be deformed, and the device can be fixed and fit on the pipe 1 to be cooled;

[0041] The distances between the displacement plate 5 and the pipeline to be cooled 1 and the internal leakage valve 2 are not less than 20 cm.

[0042] Both ends of the extrusion surface 52 are displacement plates 5, so that when the two semi-cylindrical shells 31 are covered, both ends are displacement plates 5, and no holes will be generated between the internal push plate structure and the side wall of the semi-cylindrical shell 31 due to deformation of the elastic silicone plate 51.

[0043] A method for cooling and treating pipeline defects in a urea-ammonia production system comprises the following steps:

[0044] S1: Open the two semi-cylindrical shells 31, and align the lock hole 4 with the outer wall of the pipe 1 to be cooled, and close the two semi-cylindrical shells 31 by rotation to form a complete cylindrical tank 3. At this time, since the flexible metal shell 41 is squeezed and deformed by the outer wall of the pipe 1 to be cooled, and fits the outer wall of the pipe 1 to be cooled, the activation device is started to activate the electrorheological fluid inside;

[0045] S2: Then open the sealing cover and pour dry ice into the cylindrical tank 3 through the pouring hole 32, and close the sealing cover again;

[0046] S3: Dry ice is filled three times. The cylindrical tank 3 is filled up for the first time. The dry ice is filled for the second and third time at the cooling time points of 45 minutes, 90 minutes and 120 minutes respectively to ensure that the dry ice is in full contact with the pipe 1 to be cooled and the internal leaking valve 2;

[0047] S4: After confirming that the temperature on both sides of the pipeline defective position has cooled down to the ambient temperature, it can be determined that the defective position has crystallized, and operation processing can be performed at the defective position.

[0048] The present solution also provides a method for measuring temperature using a temperature sensor. By this method, the value of the temperature sensor is preset. When the preset value is reached, it is inferred that the amount of dry ice sublimation inside has reached a certain level, and the movement of the push plate structure can be achieved to release carbon dioxide. Specifically, the effect of dry ice will cause a temperature difference change inside. Therefore,

[0049] S1: Set the real-time temperature difference change value during operation to T f ;

[0050] S2: Set up multiple control groups and record the temperature changes by time group as T1[1, 2, 3, ...m], T2[1, 2, 3, ...m]......T n [1, 2, 3, ..., m], where m is the total number of temperature points measured by the temperature sensor;

[0051] S3: Calculate the average measured temperature at the pth position in the temperature record data of the control group 1: 2 f+1 is the total number of points centered at the pth point. The pth point is the point where the temperature difference rate of change decreases slowly during recording. The sublimation of dry ice will cause the temperature to rise and release carbon dioxide. At the same time, when the amount of dry ice decreases due to sublimation, the rate of temperature drop will slow down. That is, the point where the temperature difference rate of change decreases slowly is the point after the amount of dry ice decreases by a certain amount. Take the first set of data as an example;

[0052] S4: Calculate the average value of the historical measured temperature at the pth location Comparison is made with the average values ​​of several control groups;

[0053] S5: Subtract the historical average value in step 4 from the average value at point p in the nth group to get the temperature difference, that is,

[0054] S6: When T f The temperature is greater than T p The electric push rod can be started.

[0055] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A cooling treatment device for pipeline defects in a urea-ammonia production system, comprising a pipeline to be cooled (1) and an internal leakage valve (2), characterized in that: The invention also comprises a cylindrical tank (3), wherein the cylindrical tank (3) comprises two semi-cylindrical shells (31), and the two semi-cylindrical shells (31) are opened and closed by hinges; a lock hole (4) is provided at the center of the top and bottom of the cylindrical tank (3), and the surface of the lock hole (4) is in contact with the outer wall of the pipe (1) to be cooled; a push plate structure is provided inside the semi-cylindrical shell (31); and a pouring hole (32) is also provided at the top of the cylindrical tank (3), and a sealing cover is installed on the top of the pouring hole (32), and the pouring hole (32) is used to pour dry ice into the cylindrical tank (3).

2. The device for cooling and treating pipeline defects in a urea-ammonia production system according to claim 1, characterized in that: The push plate structure comprises an inverted L-shaped displacement plate (5) and an inverted L-shaped elastic silicone plate (51); the displacement plate (5) and the elastic silicone plate (51) are staggered and connected to form an extrusion surface (52); the extrusion surface (52) is slidably arranged with the inner bottom wall of the semi-cylindrical shell (31); a gap is arranged between the outer wall of the extrusion surface (52) and the inner wall of the semi-cylindrical shell (31); and an electric push rod is arranged between the outer wall of the displacement plate (5) and the inner wall of the semi-cylindrical shell (31); the displacement plate (5) comprises an arc-shaped vertical plate (53) and a horizontal plate (54) arranged at the top end of the arc-shaped vertical plate (53); a vent hole (55) is opened at the top of the horizontal plate (54); and a docking hole (33) is opened at the top of the semi-cylindrical shell (31).

3. The device for cooling and treating pipeline defects in a urea-to-ammonia system according to claim 1, characterized in that: A layer of heat-insulating cotton is fitted on the inner wall of the semi-cylindrical shell (31) and the surface of the push plate structure.

4. The device for cooling and treating pipeline defects in a urea-to-ammonia system according to claim 1, characterized in that: The surface of the lock hole (4) is also fixedly provided with a flexible metal shell (41), and the space between the flexible metal shell (41) and the surface of the lock hole (4) is filled with electrorheological fluid; and an activation device is also included, and the activation device provides an activation signal for the electrorheological fluid.

5. The device for cooling and treating pipeline defects in a urea-to-ammonia system according to claim 2, characterized in that: The docking hole (33) is arranged on the displacement path of the vent hole (55) of the transverse plate (54).

6. The device for cooling and treating pipeline defects in a urea-to-ammonia system according to claim 3, characterized in that: The insulation cotton is 5 cm thick, and the distance between the displacement plate (5) and the pipeline to be cooled (1) and the internal leakage valve (2) is not less than 20 cm.

7. The device for cooling and treating pipeline defects in a urea-to-ammonia system according to claim 5, characterized in that: A temperature sensor is arranged inside the cylindrical tank (3), and the temperature sensor is electrically connected to the electric push rod.

8. The device for cooling and treating pipeline defects in a urea-to-ammonia system according to claim 5, characterized in that: Both ends of the extrusion surface (52) are displacement plates (5).

9. The device for cooling and treating pipeline defects in a urea-to-ammonia system according to claim 5, characterized in that: A plurality of slide rails (34) are arranged at the bottom of the cylindrical tank (3); a stepped groove (35) is also provided at the bottom of the slide rail (34); a limiting convex edge (36) is provided on the side wall of the stepped groove (35); the limiting convex edge (36) is arranged on the side close to the pipeline (1) to be cooled; a warping edge (56) is hingedly connected at the bottom of the arc-shaped vertical plate (53); the side walls at both ends of the warping edge (56) match the inner wall of the stepped groove (35), and the front end of the warping edge (56) abuts against the rear end of the limiting convex edge (36); and the two sides of the bottom of the arc-shaped vertical plate (53) are slidably fitted with the slide rail (34).

10. The device for cooling and treating pipeline defects in a urea-ammonia production system according to claim 7, characterized in that: The method of controlling the electric push rod with the temperature sensor is as follows: S1: Set the real-time temperature difference change value to Tf; S2: record the temperature changes by time group as T1[1, 2, 3, ..., m], T2[1, 2, 3, ...m]......Tn[1, 2, 3, ...m], where m is the total number of times the temperature sensor measures the temperature; S3: Calculate the average measured temperature at the pth position in the first group of temperature record data: 2f+1 is the total number of points centered at point p. Point p is the point where the temperature difference rate decreases slowly during recording, indicating that a large amount of dry ice sublimates and releases carbon dioxide. Take the first set of data as an example; S4: Calculate the average value of the historical measured temperature at the pth location S5: Subtract the historical average value in step 4 from the average value at point p in the nth group to get the temperature difference, that is, S6: When the temperature of Tf is greater than Tp, the electric push rod can be started.

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