Electrode heating type urea hydrolyzer

Abstract

The invention belongs to the technical field of ammonia preparation through urea hydrolysis, and particularly discloses an electrode heating type urea hydrolyzer which comprises a hydrolyzer body, an electrode heating assembly arranged in the hydrolyzer body, a gas-liquid separation assembly used for achieving gas-liquid separation and a monitoring assembly used for monitoring operation parameters. The top of the hydrolyzer body is provided with an outlet pipeline, the bottom of the hydrolyzer body is communicated with a liquid inlet pipeline, and the gas-liquid separation assembly is arranged at the top of the hydrolyzer body; the monitoring assembly comprises a liquid level meter for monitoring the liquid level in the hydrolyzer body, a thermometer for monitoring the temperature in the hydrolyzer body, and a pressure transmitter for monitoring the internal pressure of the outlet pipeline and the liquid inlet pipeline. The electric heating conversion efficiency can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of urea hydrolysis for ammonia production, in particular to an electrode heating type urea hydrolysis device. BACKGROUND

[0002] The urea hydrolysis for ammonia production process is the mainstream technical solution in the field of SCR denitration reductant preparation, and the core equipment is a urea hydrolysis device. The device adopts a reboiler structure, the tube passes through saturated steam with a pressure of 0.8-1.0 MPa as a heating heat source, and the shell passes through urea solution and hydrolysis product gas.

[0003] In the scenario of power plants and the like with suitable steam sources, steam heating type urea hydrolysis devices are widely used, but there are two major problems: first, the corrosion and maintenance problems are prominent. The trace amount of chloride ions and other corrosion components contained in the urea raw material will continuously enrich during the continuous operation of the hydrolysis device, and the urea hydrolysis reaction will generate intermediate products and by-products that are corrosive. Even if the industry conventionally uses intermittent blowdown to control the concentration of corrosion components, the corrosiveness of the hydrolysis liquid cannot be completely eliminated. The shell and internal heat exchange tube bundle of the existing urea hydrolysis device are mostly made of 316L stainless steel, and the wall thickness of the heat exchange tube bundle is only about 2 mm. It is inevitable to be corroded because it is immersed in the hydrolysis liquid for a long time and needs to withstand the working pressure. In actual application, the overall service life of the heat exchange tube bundle is about 5 years, during which it needs to be maintained once a year, and it needs to be overhauled or replaced as a whole after 5 years. There are problems of high replacement cost and complex construction process.

[0004] For some SCR denitration projects in the non-electricity industry such as steel and cement, steam heating type urea hydrolysis devices cannot be used due to the lack of suitable steam sources, and electric heating type urea hydrolysis devices are usually selected. The existing electric heating type urea hydrolysis device is mostly configured with a resistance heater, which has the advantages of simple structure and low manufacturing cost, but has obvious defects: first, the electric heating conversion efficiency is low; second, the resistance heating element needs to be directly immersed in the hydrolysis liquid, which is easy to be corroded by the corrosion components in the hydrolysis liquid, and the surface temperature of the resistance heating element is significantly higher than the medium temperature, which not only easily causes the heat exchange tube to be scaled, but also causes the heating element to be corroded and damaged, and there is a certain safety hazard. SUMMARY

[0005] The present application provides an electrode heating type urea hydrolysis device, which aims to improve the electric heating conversion efficiency.

[0006] The application is achieved by the following technical scheme: an electrode heating type urea hydrolyzer, comprising a hydrolyzer body, an electrode heating assembly arranged in the hydrolyzer body, a gas-liquid separation assembly for realizing gas-liquid separation, and a monitoring assembly for monitoring operating parameters; an outlet pipeline is arranged at the top of the hydrolyzer body, a liquid inlet pipeline is communicated with the bottom of the hydrolyzer body, the gas-liquid separation assembly is arranged at the top of the hydrolyzer body, and the monitoring assembly comprises a liquid level meter for monitoring the liquid level in the hydrolyzer body, a thermometer for monitoring the temperature in the hydrolyzer body, and a pressure transmitter for monitoring the internal pressure of the outlet pipeline and the liquid inlet pipeline.

[0007] Compared with the prior art, the present application has the following advantages and beneficial effects: The electrode heating assembly of the present application can be directly powered by 6kV high-voltage plant power, and is immersed heating, the electrode directly contacts with the hydrolysis liquid in the hydrolyzer body, the electric energy can be directly converted into heat energy of the hydrolysis liquid, the intermediate heat transfer medium and transmission link are saved, the heat energy loss is greatly reduced, and the electric heating conversion efficiency is effectively improved.

[0008] In the present application, the hydrolyzer body integrates the electrode heating assembly, the gas-liquid separation assembly and the monitoring assembly, the gas-liquid separation assembly at the top can directly separate the ammonia vapor generated by hydrolysis, without the need for additional independent gas-liquid separation equipment, reducing the complexity of the system pipeline, and at the same time, the layout of the hydrolyzer body with the liquid inlet pipeline communicated at the bottom and the outlet pipeline arranged at the top realizes the orderly flow of urea solution feeding and ammonia vapor discharging, greatly compressing the floor area of the entire equipment, and being more suitable for application scenarios with limited space.

[0009] The gas-liquid separation assembly at the top of the hydrolyzer body can efficiently separate the liquid droplets carried in the ammonia vapor, improve the dryness of the ammonia vapor, avoid the condensation of the liquid droplets in the outlet pipeline and the combination with the urea that has not completely reacted to form crystals, reduce the plugging probability of the outlet pipeline and the subsequent denitration reactor pipeline from the source, reduce the frequency of pipeline cleaning and maintenance, and ensure the continuous and stable operation of the denitration system.

[0010] The liquid level meter in the present application can monitor the liquid level in the hydrolyzer body in real time, provide accurate data support for the liquid supplementing operation of the liquid inlet pipeline, and avoid the decrease of gas-liquid separation effect caused by too high liquid level or the damage of electrode dry burning caused by too low liquid level; The thermometer can monitor the temperature of the hydrolysis liquid in real time, provide basis for power adjustment of the electrode heating assembly, ensure that the urea hydrolysis reaction is always in the best temperature range, and ensure the hydrolysis reaction efficiency and the ammonia generation amount; The pressure transmitters of the outlet pipeline and the liquid inlet pipeline can monitor the pressure state of the outlet and the inlet stage respectively, which can prevent the safety risk caused by the high pressure of the outlet pipeline and ensure the stable feeding of the liquid inlet pipeline, avoid the influence of the fluctuation of the feeding pressure on the stability of the hydrolysis reaction, realize the closed loop monitoring of the pressure of the whole process of the equipment operation, and be safer in use.

[0011] Further, the hydrolyzer body comprises an inner cylinder and an outer cylinder, the inner cylinder is located at the upper part of the outer cylinder and inside the outer cylinder, a communication hole is arranged at the bottom of the inner cylinder and communicates with the outer cylinder, the top of the inner cylinder is connected with the inner top of the outer cylinder through a mounting piece, an insulation layer is arranged between the inner cylinder and the outer cylinder, and the electrode heating assembly is mounted in the inner cylinder.

[0012] Beneficial effects: in the scheme, the electrode heating assembly is centrally mounted in the inner cylinder, the inner cylinder can be used as a neutral point for electrode heating to maintain internal potential balance, meanwhile, the inner cylinder and the outer cylinder are connected through the mounting piece, and the inner cylinder and the outer cylinder are insulated and isolated through the insulation layer, which can effectively avoid problems such as electric leakage and potential disorder in the electrode heating process, prevent the safety hazards and the risk of electric shock caused by the electrification of the outer cylinder, and ensure the stable operation of the high-voltage electrode heating system.

[0013] The communication hole is arranged at the bottom of the inner cylinder, which can realize the circulation of the medium between the inner cylinder and the outer cylinder. After the urea solution enters the outer cylinder from the bottom, it can enter the inner cylinder through the communication hole, contact the electrode and be heated, and the product after the hydrolysis reaction can also flow back to the outer cylinder through the communication hole, forming the circulation of the medium between the inner cylinder and the outer cylinder, which can strengthen the uniform heating and mixing of the urea solution and improve the conversion rate of the urea hydrolysis reaction and reduce the residual urea that is not completely reacted in the local part.

[0014] Further, the mounting piece is provided with at least two groups, the two groups of mounting pieces are respectively located on the two sides of the outer cylinder, the mounting piece comprises a support plate and a connecting bolt, one end of the support plate is fixedly connected with the inner side wall of the outer cylinder, and the top of the inner cylinder is connected with the support plate through the connecting bolt.

[0015] Beneficial effects: the two groups of mounting pieces are distributed on the two sides of the outer cylinder, which can uniformly disperse the stress of the top of the inner cylinder to two symmetrical points of the outer cylinder, avoid the inclination and deviation of the inner cylinder caused by unilateral installation, and the mounting piece in the scheme comprises a support plate and a connecting bolt, the connecting bolt is used for fixing the support plate and the inner cylinder, so as to realize the connection and fixation of the inner cylinder.

[0016] Further, the support plate and the outer cylinder are connected with a reinforcing rib.

[0017] Beneficial effect: the setting of the reinforcing rib can strengthen the strength of the cantilevered support plate, that is, it can effectively strengthen the connection strength of the support plate and the outer cylinder, disperse the gravity of the inner cylinder and the electrode heating assembly borne by the support plate, resist the lateral stress caused by medium impact and temperature change under high pressure and high temperature working conditions, avoid deformation failure problems such as bending and breaking of the support plate, and ensure the installation stability of the inner cylinder.

[0018] Further, an insulating gasket is arranged between the support plate and the inner cylinder.

[0019] Beneficial effect: such arrangement can ensure the insulation of the outer cylinder and the inner cylinder.

[0020] Further, the electrode heating assembly comprises three-phase electromagnetic heating electrodes, the three-phase electromagnetic heating electrodes are distributed in a triangular shape, the three-phase electromagnetic heating electrodes are connected with the hydrolyzer body, one end of the liquid inlet pipeline inside the hydrolyzer body branches into three distribution pipes, and the three distribution pipes correspond to three-phase electrodes of the three-phase electromagnetic heating electrodes respectively.

[0021] Beneficial effect: the three-phase electromagnetic heating electrodes are distributed in a triangular shape, which can form a uniform and symmetrical heating field in the inner cylinder, avoiding local heat concentration or heating blind area; at the same time, the three distribution pipes correspond to the three-phase electrodes respectively, so that the urea solution can be directly delivered to the heating area of each electrode, allowing the solution to fully contact the high-temperature electrode at the initial stage of entering the reaction zone, greatly improving the uniformity of solution heating and avoiding the problem of incomplete hydrolysis reaction caused by local insufficient heating.

[0022] The three-phase electrodes distributed in a triangular shape can form a stable high-voltage electric field, and cooperate with the direct contact heating mode, so that the electric energy can be directly converted into solution heat energy, reducing the heat loss of traditional indirect heating; and the solution is accurately sent to each electrode area through the three distribution pipes, which can quickly reach the required temperature for hydrolysis reaction, shorten the reaction start-up time, improve the overall hydrolysis conversion rate of urea, and thus improve the generation efficiency of ammonia vapor, meeting the demand of reducing agent supply of the denitration system.

[0023] Further, the three-phase electrodes of the three-phase electromagnetic heating electrodes are each connected with a conductor, one end of the conductor penetrates through the top of the hydrolyzer body and is connected with a connecting flange, the top of the hydrolyzer body is connected with three interface flanges, the three-phase electrodes of the three-phase electromagnetic heating electrodes are connected with the three interface flanges through the three connecting flanges respectively, and an insulator is arranged between the conductor and the interface flanges and the connecting flanges.

[0024] Beneficial effects: The three-phase electrode is matched with a conductor, and an insulator is arranged between the conductor and the connecting port flange and the connecting flange, which can effectively block the conduction path between the electrode and the hydrolyzer body, avoid electrical faults such as leakage and short circuit under high-voltage electric field, and ensure the stability of the neutral point potential of the inner cylinder, prevent the damage of the equipment caused by the electrification of the outer cylinder, and reduce the risk of electric shock. It is suitable for direct power supply conditions of 6kV high-voltage plant power supply.

[0025] The electrode is connected with the interface flange at the top of the hydrolyzer body through the connecting flange. The sealing structure of the flange connection can effectively resist the design pressure inside the hydrolyzer, prevent the leakage of high-temperature and high-pressure hydrolysis medium and ammonia vapor from the connecting part of the electrode and the body, and ensure the sealing performance and operation safety of the equipment under high pressure and high temperature conditions, avoid material waste and environmental risk caused by medium leakage.

[0026] The three interface flanges correspond to the three-phase electrode one by one, and the fastening structure matched with the flange connection can accurately fix the triangular distribution position of the three-phase electrode, prevent the electrode from shifting and shaking due to medium impact and temperature fluctuation during equipment operation, ensure the uniformity of the heating field, and avoid problems such as local uneven heating and discharge between electrodes caused by electrode position deviation.

[0027] The flange connection is a detachable structure. Compared with the fixed connection mode such as welding, the electrode can be disassembled and assembled without destructive disassembly of the hydrolyzer body, which greatly shortens the operation time of electrode maintenance and replacement.

[0028] Further, the top of the hydrolyzer body is connected with a gas-liquid separation cylinder, the outlet pipeline is communicated with the top of the gas-liquid separation cylinder, and the gas-liquid separation assembly is located inside the gas-liquid separation cylinder. The gas-liquid separation assembly comprises a guide pipe and a flow guide cylinder which are coaxially connected with each other. The bottom end of the flow guide cylinder is communicated with the inside of the hydrolyzer body. A plurality of spiral blades are arranged in the flow guide cylinder. A plurality of through holes are formed in the side wall of the guide pipe. The bottom of the gas-liquid separation cylinder is communicated with a reflux pipe, and the bottom end of the reflux pipe is located in the hydrolyzer body.

[0029] Beneficial effects: The spiral blades in the flow guide cylinder can make the rising ammonia vapor form a rotating fluid. Under the action of centrifugal force, the liquid droplets carried in the ammonia vapor will be thrown to the inner wall of the flow guide cylinder and fall along the wall. At the same time, the through holes in the side wall of the guide pipe can further collect the liquid droplets which are not completely separated. The double separation structure can significantly improve the dryness of the ammonia vapor, avoid the condensation of liquid droplets to form crystals after entering the outlet pipeline, reduce the plugging probability of the outlet pipeline and the subsequent denitration reactor pipeline from the source, and ensure the continuous and stable operation of the denitration system.

[0030] The reflux pipe communicated with the bottom of the gas-liquid separation cylinder can reflux the separated liquid drops into the hydrolyzer body, so that the material can participate in the hydrolysis reaction again, avoids waste of urea raw material, improves the overall urea hydrolysis conversion rate, reduces the material cost of the reducing agent preparation, and reduces the environmental problems caused by waste liquid discharge.

[0031] The gas-liquid separation assembly is integrated in the gas-liquid separation cylinder at the top of the hydrolyzer body, and the guide pipe is coaxially communicated with the flow guide cylinder, so that a compact vertical separation structure is formed, an independent gas-liquid separation device does not need to be additionally arranged, the layout of the system pipeline is greatly simplified, and the floor area of the whole device is reduced.

[0032] Further, the outlet pipeline is further connected with a pressure regulating valve, and the liquid inlet pipeline is further connected with a pneumatic on-off valve, a flow meter, a liquid inlet regulating valve and a check valve in sequence.

[0033] Beneficial effects: The pressure regulating valve is used for regulating the internal pressure of the hydrolyzer and the external pipeline pressure, the flow meter on the liquid inlet pipeline can monitor and record the feeding flow of the urea solution in real time, and provides a basis for system operation data tracing and material balance calculation; the liquid inlet regulating valve can realize closed-loop precise regulation and control of the feeding amount in combination with the flow meter data and the liquid level signal in the hydrolyzer, so that the liquid level in the hydrolyzer is stably ensured in a reasonable range, the gas-liquid separation effect is avoided to be affected due to excessively high liquid level, or the electrode is avoided to be dry-burned due to excessively low liquid level; the pneumatic on-off valve can quickly cut off the feeding in the scenes of equipment start-stop, fault emergency and the like, and improves the emergency response capability of the system.

[0034] The check valve on the liquid inlet pipeline can effectively block the backflow of the high-temperature and high-pressure medium in the hydrolyzer to the liquid inlet pipeline, avoid damage of the high-temperature medium to precise instruments and valve parts such as the flow meter and the regulating valve, prolong the service life of the feeding system equipment, prevent pressure abnormity of the feeding pipeline caused by backflow, and guarantee the one-way stability of the feeding process.

[0035] Further, a safety pressure relief valve is arranged at the top of the hydrolyzer body.

[0036] Beneficial effects: When the pressure in the hydrolyzer is higher than the design pressure due to uncontrolled electrode heating power, pipeline blockage, abnormal reaction and the like, the safety pressure relief valve can be automatically opened to release the excessive pressure, avoid rupture, explosion and other malignant safety accidents of the hydrolyzer body due to overpressure, and guarantee the safety of personnel and the site around the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0037] The drawings described herein are used to provide further understanding of the embodiments of the present application, constitute a part of the present application, and do not constitute a limitation to the embodiments of the present application. In the drawings: Figure 1Structure schematic diagram of an embodiment of the electrode heating type urea hydrolyzer of the present application after installing monitoring components on the liquid inlet pipeline and the outlet pipeline; Figure 2 Structure schematic diagram of an embodiment of the electrode heating type urea hydrolyzer of the present application; Figure 3 Structure schematic diagram of an embodiment of the electrode heating type urea hydrolyzer of the present application; Figure 2 Structure schematic diagram of an embodiment of the electrode heating type urea hydrolyzer of the present application; Figure 4 Structure schematic diagram of an embodiment of the electrode heating type urea hydrolyzer of the present application; Figure 5 Structure schematic diagram of an embodiment of the electrode heating type urea hydrolyzer of the present application; Figure 6 Structure schematic diagram of an embodiment of the electrode heating type urea hydrolyzer of the present application; Figure 7 Structure schematic diagram of an embodiment of the electrode heating type urea hydrolyzer of the present application; Figure 8 Structure schematic diagram of an embodiment of the electrode heating type urea hydrolyzer of the present application;

[0038] Markings in the drawings and corresponding names of parts: Hydrolyzer body 1, outer cylinder 101, inner cylinder 102, thermometer 103, liquid level gauge 104, safety pressure relief valve 105; Three-phase electromagnetic heating electrode 2, conductor 201, connecting flange 202, interface flange 203, insulator 204, connecting pipe 205; Gas-liquid separation assembly 3, guide pipe 301, flow guide cylinder 302, blade 3022, return pipe 303; Outlet pipeline 4, pressure regulating valve 401, outlet pipeline pressure transmitter 402; Liquid inlet pipeline 5, distribution pipe 501, pneumatic on-off valve 502, flow meter 503, liquid inlet regulating valve 504, check valve 505, liquid inlet pipeline pressure transmitter 506; Mounting 6, reinforcing rib 601, support plate 602, insulating gasket 603, connecting bolt 604; Gas-liquid separation cylinder 7, partition plate 701, communication hole 8, skirt 9. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present application more clear and obvious, the present application will be further described in detail below with examples and drawings, the schematic embodiments of the present application and the description thereof are only used to explain the present application, and do not limit the present application.

[0040] As one embodiment of the present application, as shown in Figures 1-2 The present embodiment provides an electrode heating type urea hydrolyzer, which comprises a hydrolyzer body 1, an electrode heating assembly arranged in the hydrolyzer body 1, a gas-liquid separation assembly 3 for realizing gas-liquid separation, and a monitoring assembly for monitoring operating parameters; the top of the hydrolyzer body 1 is provided with an outlet pipeline 4, and the bottom of the hydrolyzer body 1 is communicated with a liquid inlet pipeline 5; in the present embodiment, the outlet pipeline 4 is used for conveying product gas in the gas phase in the urea hydrolyzer to a denitration reactor zone, and the liquid inlet pipeline 5 is used for supplementing urea molten salt to the inside of the hydrolyzer body 1. The gas-liquid separation assembly 3 is arranged at the top of the hydrolyzer body 1, and the monitoring assembly comprises a liquid level meter 104 for monitoring the liquid level in the hydrolyzer body 1, a thermometer 103 for monitoring the temperature in the hydrolyzer body 1, and pressure transmitters for monitoring the pressure in the outlet pipeline 4 and the liquid inlet pipeline 5; the pressure transmitter located on the outlet pipeline 4 is an outlet pipeline pressure transmitter 402, and the pressure transmitter located on the liquid inlet pipeline 5 is a liquid inlet pipeline pressure transmitter 506.

[0041] In one embodiment, as shown in Figure 1 A pressure regulating valve 401 is further connected to the outlet pipeline 4, which is used for adjusting the internal pressure of the hydrolyzer and the external pipeline pressure; from left to right, a pneumatic on-off valve 502, a flow meter 503, a liquid inlet regulating valve 504, and a check valve 505 are further connected to the liquid inlet pipeline 5 in sequence, and the liquid inlet pipeline pressure transmitter 506 is close to the hydrolyzer body 1.

[0042] The liquid inlet regulating valve 504 forms a closed loop interlocking control with the liquid level of the hydrolysis liquid (the liquid level meter 104); when the liquid level in the hydrolyzer body 1 decreases, urea molten salt is supplemented through the liquid inlet regulating valve 504, which has the functions of pressure matching and liquid level tracking; the flow meter 503 has the function of monitoring and recording the amount of urea solution; in the present embodiment, the liquid level meter 104 is located at the top of the hydrolyzer body 1 and is used for monitoring the liquid level in the hydrolyzer body 1, and a non-contact liquid level meter such as a radar liquid level meter is usually used.

[0043] In the present embodiment, the thermometer 103 is arranged below the lowest liquid level of the hydrolyzer body 1 and is used for monitoring the temperature of the liquid phase of the hydrolysis liquid; in the present embodiment, a double-branch thermistor is used.

[0044] In one embodiment, as shown in Figure 1 and Figure 2 A safety relief valve 105 is arranged at the top of the hydrolyzer body 1, which is used for pressure relief in abnormal conditions to prevent dangerous accidents caused by the gas phase pressure of the urea hydrolyzer exceeding the design pressure.

[0045] In one embodiment, as shown in Figure 2As shown, the hydrolyzer body 1 includes an inner cylinder 102 and an outer cylinder 101. The inner cylinder 102 is located above and inside the outer cylinder 101. Figure 6 As shown, the bottom of the inner cylinder 102 is provided with a connecting hole 8 that communicates with the outer cylinder 101, and the connecting hole 8 is located in the center of the inner cylinder 102, so that the outer cylinder 101 and the inner cylinder 102 are connected, and the liquids in the outer cylinder 101 and the inner cylinder 102 are in communication.

[0046] like Figure 2 As shown, the top of the inner cylinder 102 is connected to the top of the inner side of the outer cylinder 101 by a mounting piece 6. An insulating layer is provided between the inner cylinder 102 and the outer cylinder 101. The electrode heating assembly is installed inside the inner cylinder 102.

[0047] In one embodiment, the hydrolyzer body 1 is a vertical cylindrical pressure vessel with elliptical heads at both its top and bottom. A skirt 9 is connected to the lower part of the hydrolyzer body 1, providing overall support. The design pressure of the hydrolyzer body 1 is 1.6. The design temperature is 200℃. The outer cylinder 101 can be made of materials such as 316L, 2205, 2507, TA2+Q345R composite board, etc. The inner cylinder 102 is set inside as a neutral point. Electrode heating components are set inside the inner cylinder 102. The inner cylinder 102 can be made of materials such as 316L, 2205, 2507, 1.4529, TA10, etc. The insulation layer between the inner cylinder 102 and the outer cylinder 101 is made of insulating material, such as silicon nitride ceramic or polyimide. The inner cylinder 102 and the outer cylinder 101 are supported and isolated by the insulation layer, ensuring the insulation between the outer cylinder 101 and the inner cylinder 102, so that the inner cylinder 102 is self-heating zero potential and maintains the internal potential balance.

[0048] In one embodiment, such as Figure 2 and Figure 5 As shown, there are at least two sets of mounting components 6, which are located on both sides of the outer cylinder 101. If there are multiple sets of mounting components 6, they are evenly distributed circumferentially. In this embodiment, the mounting component 6 includes a support plate 602 and a connecting bolt 604. One end of the support plate 602 is fixedly connected to the inner wall of the outer cylinder 101, so that the support plate 602 cantilevered on the inner wall of the outer cylinder 101. The support plate 602 is welded and fixed to the outer cylinder 101. In this embodiment, a reinforcing rib 601 is connected between the support plate 602 and the outer cylinder 101 to strengthen the strength of the cantilevered support plate 602.

[0049] The top of the inner cylinder 102 is connected with the support plate 602 through the connecting bolt 604 in the embodiment, so that the connection and fixation of the inner cylinder 102 are realized. The insulating gasket 603 is arranged between the support plate 602 and the inner cylinder 102 in the embodiment. The connecting bolt 604 passes through the insulating gasket 603, so that the insulating gasket 603 is connected with the support plate 602 and the inner cylinder 102 together. The inner cylinder 102 is isolated from the support plate 602 through the insulating gasket 603, so that the insulation of the outer cylinder 101 and the inner cylinder 102 can be ensured.

[0050] In one embodiment, as shown in Figure 2 The electrode heating assembly in the embodiment includes a three-phase electromagnetic heating electrode 2. Figure 4 The three-phase electromagnetic heating electrode 2 is distributed in a triangular shape, that is, the three-phase electrodes of the three-phase electromagnetic heating electrode 2 are distributed in a triangular shape. The three-phase electromagnetic heating electrode 2 is connected with the hydrolyzer body 1. The electrode of the urea hydrolyzer in the embodiment adopts a fixed electrode, has no mechanical loss, has a low failure rate, and adjusts the power (5%-100%) through the mode of IGBT voltage regulator stepless voltage regulation.

[0051] The temperature inside the hydrolyzer body 1 is controlled in a control voltage mode. A conductivity meter is arranged. The conductivity of the hydrolyzing liquid is monitored according to the conductivity meter to calculate the required power. The load of the hydrolyzer is automatically regulated through feedback of the IGBT to make the hydrolyzer run in a standby state at low power, so that the hydrolyzer is maintained in a certain temperature range of 60-100℃. When the temperature needs to be raised, the voltage is immediately regulated to quickly raise the load.

[0052] As shown in Figure 2 The liquid inlet pipeline 5 is branched into three distribution pipes 501 at one end inside the hydrolyzer body 1. The three distribution pipes 501 correspond to the three-phase electrodes of the three-phase electromagnetic heating electrode 2 respectively. The distribution pipe 501 is not in contact or connected with the electrode, so as to avoid direct contact to cause electrode short circuit or the distribution pipe to be ablated by the high-temperature electrode. The material of the distribution pipe 501 in the embodiment is Teflon.

[0053] In one embodiment, as shown in Figure 2 and Figure 3As shown, the three-phase electrode of the three-phase electromagnetic heating electrode 2 is connected with a conductor 201, one end of the conductor 201 penetrates through the top of the hydrolyzer body 1 and is connected with a connecting flange 202, the conductor 201 is crimped or fixed in other ways with the connecting flange 202, three interface flanges 203 are connected with the top of the hydrolyzer body 1, the positions of the three interface flanges 203 are opposite to the triangular distribution positions of the three-phase electrode, in the embodiment, three connecting pipes 205 are welded on the top of the hydrolyzer body 1, the three interface flanges 203 are respectively crimped or welded with the end portions of the three connecting pipes 205, the three-phase electrode of the three-phase electromagnetic heating electrode 2 is connected with the three interface flanges 203 through the three connecting flanges 202, the interface flanges 203 and the connecting flanges 202 are fixed by bolts, which is convenient for dismounting and mounting in the later period.

[0054] As shown in the figure, Figure 3 The conductor 201 is provided with an insulator 204 between the interface flange 203 and the connecting flange 202, in the embodiment, the insulator 204 is bonded on the upper portion of the conductor 201 or is tightly fixed by the interface flange 203 and the connecting flange 202, the insulator 204 plays an insulating role, so as to block the conduction path between the electrode and the hydrolyzer body, thereby ensuring the safety.

[0055] In the embodiment, the three-phase electromagnetic heating electrode 2 is directly powered by 6kV high-voltage plant power, without additional configuration of a transformer, the high-voltage three-phase electrode is connected by a triangular connection mode, the power density is high, without neutral point grounding, the electrode is attached with the insulator 201 with the connecting flange 202, and is connected with the interface flange 203 through the connecting flange 202, which can bear the gravity of the three-phase electrode, and because the hydrolyzer body 1 is a pressure vessel, the flange structure can also be used for sealing.

[0056] In one embodiment, as shown in the figure, Figure 2 The top of the hydrolyzer body 1 is connected with a gas-liquid separation cylinder 7, the outlet pipeline 4 communicates with the top of the gas-liquid separation cylinder 7, and the gas-liquid separation assembly 3 is located inside the gas-liquid separation cylinder 7, which is used for separating the water carried by the steam.

[0057] As shown in the figure, Figure 7 The gas-liquid separation assembly 3 includes a guide pipe 301 and a flow guide cylinder 302 which are coaxially connected with each other, the bottom end of the flow guide cylinder 302 communicates with the inside of the hydrolyzer body 1, so as to facilitate the steam generated in the hydrolyzer body 1 to enter the flow guide cylinder 302, as shown in the figure, Figure 8 A plurality of blades 3022 which are spirally arranged are uniformly distributed in the circumferential direction of the flow guide cylinder 302, and as shown in the figure, Figure 7 A plurality of through holes are formed in the side wall of the guide pipe 301, and as shown in the figure, Figure 2As shown, the bottom of the gas-liquid separation cylinder 7 is communicated with a reflux pipe 303, the bottom end of the reflux pipe 303 is located in the hydrolysis reactor body 1, and in this embodiment, the bottom end of the reflux pipe 303 is located in the upper portion of the hydrolysis reactor body 1, and in this embodiment, the reflux pipe 303 is communicated with the cavity inside the gas-liquid separation cylinder 7, so as to facilitate the reflux of the liquid collected in the cavity inside the gas-liquid separation cylinder 7 to the inside of the hydrolysis reactor body 1 through the reflux pipe 303.

[0058] In one embodiment, the gas-liquid separation assembly 3 is provided in multiple groups, the top wall and the bottom wall of the gas-liquid separation cylinder 7 are connected with baffles 701, a plurality of insertion holes for installing the gas-liquid separation assembly 3 are formed in the baffles 701, the multiple groups of gas-liquid separation assemblies 3 are distributed in the gas-liquid separation cylinder 7 at intervals, and the two ends of the gas-liquid separation assembly 3 are respectively inserted into the insertion holes of the upper and lower baffles 701, the upper and lower baffles 701 play a connecting and supporting role on the gas-liquid separation assembly 3, and can play a separating role on the multiple groups of gas-liquid separation assemblies 3, so that the multiple groups of gas-liquid separation assemblies 3 are distributed at intervals.

[0059] The ammonia vapor generated by the hydrolysis reactor generates a rotating fluid through the flow guide cylinder 302 with blades 3022, the centrifugal force of the rotating fluid separates the water droplets carried by the ammonia vapor from the gas flow, the separated liquid droplets enter the internal cavity of the gas-liquid separation cylinder 7 through the through holes on the guide pipe 301, and finally are refluxed into the hydrolysis reactor body 1 through the reflux pipe 303.

[0060] In this embodiment, the gas-liquid separation assembly 3 with a special cyclone structure centrifugal separation structure arranged at the top is used for separating the water droplets carried in the ammonia vapor, so as to ensure the dryness of the ammonia vapor and avoid the condensation and recondensation of the crystalline body to block the pipeline during the conveying process.

[0061] Compared with the prior art, the present application has the following beneficial effects: 1) In the present application, the electrode heating method is used instead of the steam heating method in the vertical urea hydrolysis reactor, which is more simple, has no steam system and steam drainage system, and has the advantages of high thermal efficiency, strong controllability, good operation flexibility and load adaptability compared with the steam heating method; secondly, the safety and reliability of the urea hydrolysis reactor is improved, and the equipment maintenance frequency and cost are reduced; thirdly, the application range is wider, and for the SCR project without steam source or inconvenient steam source, the steam heating type urea hydrolysis reactor cannot be used, and only the electrode type urea hydrolysis reactor can be used; fourthly, it can be directly connected to the plant power system without transformer, and the connected cable is smaller; fifthly, the horizontal hydrolysis reactor is changed to vertical hydrolysis reactor, which is beneficial to the installation on site and reduces the occupied area; sixthly, compared with the conventional resistance heating type urea hydrolysis reactor, the electrode heating type urea hydrolysis reactor is more suitable, which not only has higher safety, but also has higher thermal efficiency and more convenient maintenance.

[0062] 2) Electrode heating hydrolyzer adopts IGBT voltage regulator non-polar voltage regulation mode to control power actual load range, which can reach 5%-100%, compared with conventional hydrolyzer load range, which is wider.

[0063] 3) Electrode heating hydrolyzer is provided with physical gas-liquid separation component 3 at the top, compared with the outlet ammonia steam dryness of conventional hydrolyzer, which is higher.

[0064] It is to be noted that the above description of the disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An electrode heating type urea hydrolyzer characterized by comprising: The hydrolyzer body, the electrode heating assembly arranged in the hydrolyzer body, the gas-liquid separation assembly for realizing gas-liquid separation and the monitoring assembly for monitoring operating parameters; the top of the hydrolyzer body is provided with an outlet pipeline, the bottom of the hydrolyzer body is communicated with a liquid inlet pipeline, the gas-liquid separation assembly is arranged at the top of the hydrolyzer body, and the monitoring assembly comprises a liquid level meter for monitoring the liquid level in the hydrolyzer body, a thermometer for monitoring the temperature in the hydrolyzer body and a pressure transmitter for monitoring the internal pressure of the outlet pipeline and the liquid inlet pipeline.

2. The electrode heated urea hydrolyzer according to claim 1, wherein The hydrolyzer body comprises an inner cylinder and an outer cylinder, the inner cylinder is located at the upper part of the outer cylinder and inside the outer cylinder, a communication hole is formed in the bottom of the inner cylinder and communicated with the outer cylinder, the top of the inner cylinder is connected with the inner top of the outer cylinder through a mounting piece, an insulation layer is arranged between the inner cylinder and the outer cylinder, and the electrode heating assembly is mounted in the inner cylinder.

3. The electrode heated urea hydrolyzer according to claim 2, wherein The mounting piece is provided with at least two groups, and the two groups of mounting pieces are respectively located on the two sides of the outer cylinder, the mounting piece comprises a support plate and a connecting bolt, one end of the support plate is fixedly connected with the inner side wall of the outer cylinder, and the top of the inner cylinder is connected with the support plate through the connecting bolt.

4. The electrode heated urea hydrolyzer according to claim 3, wherein The support plate and the outer cylinder are connected with a reinforcing rib.

5. The electrode heated urea hydrolyzer according to claim 3, wherein Insulating gaskets are arranged between the support plate and the inner cylinder.

6. The electrode heated urea hydrolyzer according to claim 1, wherein The electrode heating assembly comprises three-phase electromagnetic heating electrodes, the three-phase electromagnetic heating electrodes are distributed in a triangular shape, the three-phase electromagnetic heating electrodes are connected with the hydrolyzer body, one end of the liquid inlet pipeline inside the hydrolyzer body is branched into three distribution pipes, and the three distribution pipes correspond to the three-phase electrodes of the three-phase electromagnetic heating electrodes respectively.

7. The electrode heated urea hydrolyzer according to claim 6, wherein The three-phase electrodes of the three-phase electromagnetic heating electrodes are connected with conductors, one end of the conductor penetrates through the top of the hydrolyzer body and is connected with a connecting flange, the top of the hydrolyzer body is connected with three interface flanges, the three-phase electrodes of the three-phase electromagnetic heating electrodes are connected with the three interface flanges through the three connecting flanges respectively, and insulators are arranged between the conductors and the interface flanges and the connecting flanges.

8. The electrode heated urea hydrolyzer according to claim 1, wherein The top of the hydrolyzer body is connected with a gas-liquid separation cylinder, the outlet pipeline is communicated with the top of the gas-liquid separation cylinder, the gas-liquid separation assembly is located inside the gas-liquid separation cylinder, the gas-liquid separation assembly comprises a coaxial guide pipe and a flow guide cylinder which are communicated with each other, the bottom end of the flow guide cylinder is communicated with the inside of the hydrolyzer body, a plurality of blades are spirally arranged in the flow guide cylinder, a plurality of through holes are formed in the side wall of the guide pipe, the bottom of the gas-liquid separation cylinder is communicated with a reflux pipe, and the bottom end of the reflux pipe is located in the hydrolyzer body.

9. The electrode heated urea hydrolyzer according to claim 1, wherein A pressure regulating valve is further connected to the outlet pipeline, and a pneumatic on-off valve, a flow meter, a liquid inlet regulating valve and a check valve are sequentially connected to the liquid inlet pipeline.

10. The electrode heated urea hydrolyzer according to claim 1, wherein A safety pressure relief valve is arranged at the top of the hydrolyzer body.

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