Ammonia pressure measuring device for urea hydrolysis system

Abstract

The utility model discloses an ammonia pressure measuring device for a urea hydrolysis system, which comprises a first flange at the bottom, a connecting pipe, an ammonia pressure guide pipe, a second flange at the upper part and an end cover flange at the top, the first flange and the second flange are distributed in parallel up and down, the middles of the first flange and the second flange are welded and fixed through a vertically-connected connecting pipe to form an integrated structure, an ammonia pressure guiding pipe is vertically welded and fixed to the position, in the center of the inner side of the connecting pipe, of the first flange, and an air hole communicated with the ammonia pressure guiding pipe is formed in the center of the first flange; a spacer fluid filling overflow port connector is fixedly welded to the upper side of the connecting pipe, a pressure guide pipe connector is fixedly welded to the lower side of the connecting pipe, the end cover flange is arranged on the second flange and provided with screw holes distributed coaxially, and the end cover flange is provided with a spacer fluid filling port communicated with the connecting pipe. The pressure transmitter is simple, reasonable and reliable in structure, convenient to assemble and disassemble, simple to maintain and good in use stability, the damage frequency of the pressure transmitter is reduced, and the use cost is reduced.

Description

Technical Field

[0001] The utility model belongs to the field of electric power industry, and specifically relates to a device for measuring ammonia pressure in a urea hydrolysis system. Background Art

[0002] In the early days, coal-fired power generation units generally used liquid ammonia as the SCR denitrification reductant. In recent years, in order to strengthen the management of hazardous chemicals, it has been clearly proposed to accelerate the transformation of coal-fired power plants to replace liquid ammonia with urea and eliminate major hazardous sources in the liquid ammonia area. At present, the method of hydrolyzing urea to produce ammonia is widely used. At the same time, the product gas after hydrolysis is a mixture of NH3, CO2, and H2O. When the temperature is lower than 110°C, the product gas will reversely react to generate ammonium carbamate crystals that block the pipeline. On the one hand, the monitoring of ammonia pressure can ensure that the ammonia pressure in the SCR system is within the appropriate range to avoid damage to the system equipment due to excessive or low pressure; on the other hand, pressure control can ensure that the ammonia pressure in the SCR system is within the appropriate range to avoid damage to the system equipment due to excessive or low pressure. X The reaction is efficient in reducing NO X In order to reduce emissions, reduce catalyst loss, improve unit combustion efficiency and thus improve the economic benefits of thermal power plants, the correct and reliable measurement of ammonia injection pressure is of great significance.

[0003] At present, the ammonia pressure measurement interface adopts flange connection, and the pressure transmitter adopts a capillary remote transmitter with a purge ring. Due to the use of multi-stage flange connection and uneven appearance, the high-temperature electric heating wire winding heating effect is poor. If the external insulation is thickened, the operating temperature of the transmitter will be too high and the transmitter will be damaged, causing the measurement point to fail. Analysis of failure statistics found that the main reason for the failure of the measurement point was that the membrane box was corroded or the electric heating was poor, resulting in crystallization and blockage of the pressure transmission pipeline. There was no obvious improvement after multiple changes of the membrane box transmitter.

[0004] The existing ammonia pressure measurement method has the following problems: on the one hand, the electric heating pressure transmission pipeline is poor and easily causes crystallization blockage; on the other hand, ammonia directly contacts the diaphragm box transmitter and easily causes diaphragm box corrosion, resulting in transmitter measurement failure. Utility Model Content

[0005] The main technical problem solved by the utility model is to provide a device for measuring ammonia pressure in a urea hydrolysis system, which has a simple, reasonable and reliable structure, is easy to load and unload, is simple to maintain, has good stability in use, reduces the frequency of damage to the pressure transmitter, and reduces the cost of use.

[0006] In order to solve the above technical problems, a technical solution adopted by the utility model is: to provide a device for measuring ammonia pressure in a urea hydrolysis system, comprising a first flange at the bottom, a connecting pipe, an ammonia pressure-inducing pipe, a second flange at the top and an end cover flange at the top, the first flange and the second flange are parallelly distributed up and down and are welded and fixed in the middle through a vertically connected connecting pipe to form an integrated structure, the first flange is vertically welded and fixed with an ammonia pressure-inducing pipe at the center of the inner side of the connecting pipe, an air hole connected to the ammonia pressure-inducing pipe is arranged at the center of the first flange, an isolation liquid filling overflow port joint is welded and fixed on the upper side of the connecting pipe, and a pressure-inducing pipe joint is welded and fixed on the lower side, the second flange is provided with a connecting port with the same caliber as the connecting pipe, the end cover flange is arranged on the second flange and is provided with screw holes distributed coaxially, and the end cover flange is provided with an isolation liquid filling port connected to the connecting pipe.

[0007] In a preferred embodiment of the present invention, the outer wall of the connecting pipe is evenly wound with a spirally distributed high-temperature electric heating belt.

[0008] In a preferred embodiment of the present invention, the bottom of the isolation liquid filling overflow port joint is lower than the top of the ammonia pressure-leading pipe.

[0009] In a preferred embodiment of the utility model, the end cover flange is threadedly connected to an isolation liquid filling port cock on the isolation liquid filling port.

[0010] In a preferred embodiment of the utility model, a purge steam joint communicating inside and outside is vertically welded and fixed to the center of the end cover flange.

[0011] In a preferred embodiment of the present invention, plugging caps are provided on the isolation liquid filling overflow port joint and the purge steam joint.

[0012] In a preferred embodiment of the present utility model, the isolation liquid filling overflow port joint, the pressure-leading pipe joint and the purge steam joint are all configured as external threads.

[0013] The beneficial effects of the utility model are as follows: the device for measuring ammonia pressure in a urea hydrolysis system pointed out by the utility model has a simple, reasonable and reliable structure, is convenient for loading and unloading, is simple for maintenance, has good stability in use, reduces the frequency of damage to the pressure transmitter, and reduces the cost of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0015] Figure 1 This is a stereoscopic diagram of a device for measuring ammonia pressure in a urea hydrolysis system according to a preferred embodiment of the utility model;

[0016] Figure 2 yes Figure 1 sectional view of . DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] See also Figure 1 Combination Figure 2 As shown, the embodiment of the utility model includes:

[0019] A device for measuring ammonia pressure in a urea hydrolysis system comprises a first flange 1 at the bottom, a connecting pipe 2, an ammonia pressure-inducing pipe 3, a second flange 4 at the top and an end cover flange 5 at the top.

[0020] The first flange 1 and the second flange 4 are arranged in parallel up and down and are welded and fixed in the middle through a vertically connected connecting pipe 2 to form an integrated structure, thereby ensuring the use strength and stability of the entire device.

[0021] The first flange 1 is fastened to the flange of the primary pressure-taking valve of the ammonia injection pipeline to support the entire device.

[0022] An ammonia pressure pipe 3 is vertically welded and fixed to the first flange 1 at the center of the inner side of the connecting pipe 2 . An air hole 6 connected to the ammonia pressure pipe 3 is provided at the center of the first flange 1 to facilitate the introduction of ammonia into the connecting pipe 2 .

[0023] The connecting pipe 2 has a straight cylindrical shape, and a spirally distributed high-temperature electric heating belt 7 is evenly wound around the outer wall to ensure that the connecting pipe 2 is well heated.

[0024] An isolation liquid filling overflow port joint 8 is welded and fixed on the upper side of the connecting pipe 2. The bottom of the isolation liquid filling overflow port joint 8 is lower than the top of the ammonia pressure-leading pipe 3, which is convenient for ensuring that the isolation liquid has been filled in place. Pay attention to sealing it with a plugging cap before the equipment is put into use.

[0025] A pressure-leading pipe joint 9 is welded and fixed to the lower side of the connecting pipe 2 and is connected to the low-position pressure-leading pipe interface of the pressure transmitter.

[0026] The second flange 4 is provided with a connection port 10 with the same diameter as the connection pipe 2. The end cover flange 5 is arranged on the second flange 4 and is provided with coaxially distributed screw holes. The end cover flange 5 and the second flange 4 are precisely matched and can be easily assembled and disassembled.

[0027] The end cover flange 5 is provided with an isolation liquid filling port 11 connected to the connecting pipe 2 for filling the isolation liquid. The end cover flange 5 is threadedly connected with an isolation liquid filling port cock 12 on the isolation liquid filling port 11 for sealing the isolation liquid filling port 11 after the isolation liquid is filled.

[0028] The center of the end cover flange 5 is vertically welded with a purge steam joint 13 that communicates inside and outside, which can be connected to the purge steam pipeline. If there is no purge steam management, it can also be blocked with a plugging cap.

[0029] The isolation liquid filling overflow port connector 8, the pressure-leading pipe connector 9 and the purge steam connector 13 are all configured with external threads for easy connection.

[0030] All parts are made of 316 material. The first flange 1, connecting pipe 2, ammonia pressure pipe 3, second flange 4, isolation liquid filling overflow port joint 8, pressure pipe joint 9, end cover flange 5 and purge steam joint 13 are all welded by argon arc welding to ensure the strength. The size of the joint or interface can be adjusted according to the actual needs of the site.

[0031] A method for using a device for measuring ammonia pressure in a urea hydrolysis system comprises the following steps:

[0032] First, connect and fix the first flange 1 to the flange of the pressure-taking valve interface of the ammonia injection pipeline of the unit, and the ammonia gas enters the connecting pipe 2 from the ammonia pressure pipe 3 through the air hole 6; connect the pressure pipe joint 9 to the low-level pressure pipe interface of the pressure transmitter, and ensure that the high-level pressure pipe interface on one side of the pressure transmitter is horizontal and lower than the isolation liquid filling overflow port joint 8; fill the isolation liquid through the isolation liquid filling port 11 until the liquid overflows from the high-level pressure pipe interface and is flush with the high-level pressure pipe interface, and install and fix the pressure transmitter; continue to fill the isolation liquid until the isolation liquid filling overflow port joint 8 overflows the excess isolation liquid, at this time, seal it with a plug cap Fill the isolation liquid with the overflow port joint 8, and use the isolation liquid filling port plug 12 to block the isolation liquid filling port 11 to ensure that there is no leakage; by disassembling the end cover flange 5 and the second flange 4, it is convenient to check the crystallization situation inside the device and whether the isolation liquid needs to be replenished after the system is shut down; the purge steam joint 13 on the end cover flange 5 is connected to the purge steam pipeline, which is convenient for timely processing of crystallization of the device. During non-purge working hours, it is blocked with a plugging cap to ensure that there is no leakage; the high-temperature electric heating belt 7 is evenly wrapped around the outside of the connecting pipe 2 and is activated when the device is in use to ensure uniform heating and prevent the reverse reaction crystallization of the hydrolysis product gas from clogging the measuring pipeline.

[0033] The isolation liquid is silicone oil, which is combined with ammonia gas to transmit pressure.

[0034] Through the above structure, the straight cylinder shape can make the electric heating evenly and effectively heat the medium, prevent ammonia from crystallizing due to too low temperature and causing the measurement pipeline to be blocked and unable to transmit pressure, and transmit pressure by directly contacting ammonia with silicone oil, and then connecting the pressure transmitter through the pressure pipe, effectively preventing ammonia from corroding the pressure transmitter and causing measurement failure.

[0035] In summary, the utility model discloses a device for measuring ammonia pressure in a urea hydrolysis system, which has a simple, reasonable and reliable structure, is easy to load and unload, is simple to maintain, has good stability in use, reduces the frequency of damage to the pressure transmitter, and reduces the cost of use.

[0036] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, 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 device for measuring ammonia pressure in a urea hydrolysis system, characterized in that: It includes a first flange at the bottom, a connecting pipe, an ammonia pressure-leading pipe, a second flange at the top and an end cover flange at the top. The first flange and the second flange are distributed in parallel up and down and are welded and fixed in the middle through a vertically connected connecting pipe to form an integrated structure. The first flange is vertically welded and fixed with an ammonia pressure-leading pipe at the center of the inner side of the connecting pipe. The center of the first flange is provided with an air hole connected to the ammonia pressure-leading pipe. An isolation liquid filling overflow port joint is welded and fixed on the upper side of the connecting pipe, and a pressure-leading pipe joint is welded and fixed on the lower side. The second flange is provided with a connecting port with the same caliber as the connecting pipe. The end cover flange is arranged on the second flange and is provided with coaxially distributed screw holes. The end cover flange is provided with an isolation liquid filling port connected to the connecting pipe.

2. The device for measuring ammonia pressure in a urea hydrolysis system according to claim 1, characterized in that: The outer wall of the connecting pipe is evenly wound with a spirally distributed high-temperature electric heating belt.

3. The device for measuring ammonia pressure in a urea hydrolysis system according to claim 1, characterized in that: The bottom of the isolation liquid filling overflow port joint is lower than the top of the ammonia pressure-inducing pipe.

4. The device for measuring ammonia pressure in a urea hydrolysis system according to claim 1, characterized in that: The end cover flange is threadedly connected with an isolation liquid filling port cock on the isolation liquid filling port.

5. The device for measuring ammonia pressure in a urea hydrolysis system according to claim 1, characterized in that: A purge steam joint communicating with the inside and outside is vertically welded and fixed at the center of the end cover flange.

6. The device for measuring ammonia pressure in a urea hydrolysis system according to claim 5, characterized in that: The isolation liquid filling overflow port joint and the purge steam joint are provided with plugging caps.

7. The device for measuring ammonia pressure in a urea hydrolysis system according to claim 5, characterized in that: The isolation liquid filling overflow port joint, the pressure-leading pipe joint and the purge steam joint are all arranged with external threads.

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