High-efficiency urea direct-injection pyrolysis system

Abstract

The present application relates to flue gas denitration system technical field, disclose a kind of high-efficiency urea direct injection pyrolysis system, this system includes mixing unit, it includes urea solution supply line, desalted water supply line and mixed liquor supply line;Metering output unit is connected with mixed liquor supply line, it includes several metering output lines and the return line connected therewith, and the output end of each metering output line is connected with the corresponding spray gun in spray gun system;Flushing water unit, its input end is connected with desalted water supply line, and the output end is connected with metering output line;Compressed air unit includes atomizing air line and cooling air line;In the pipeline system of the application, the concentration of urea solution is adjusted and monitored by mixing unit and metering output unit multi-stage, so that it reaches spray gun, the concentration remains consistent, and the pipeline of flushing water unit is matched, to avoid the pipe blockage problem existing in pipeline system when not using or pausing using.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of flue gas denitration system, and particularly relates to a high-efficiency urea direct injection pyrolysis system. BACKGROUND

[0002] The flue gas denitration SCR reducing agent of the gas turbine-steam cycle unit is basically concentrated in liquid ammonia or ammonia water, and the process is simple, the initial investment and operation cost are low, and the system is stable, but since the liquid ammonia or ammonia water is a kind of toxic and dangerous chemical, the liquid ammonia or ammonia water storage of the gas turbine power plant is large, a major hazard source has been formed, and the safety risk is high. In view of the safety risk of liquid ammonia, the SCR denitration technology of preparing reducing agent by urea is widely used, and the reducing agent preparation technologies mainly include urea pyrolysis, urea direct injection and urea hydrolysis.

[0003] The urea pyrolysis commonly adopts high-temperature flue gas at the outlet of the gas turbine to be introduced into a urea pyrolysis furnace through a high-temperature fan to pyrolyze the urea solution to prepare ammonia; the urea hydrolysis system utilizes low-quality steam (0.8-1.0, 160-200 degrees) to make the urea solution in the reactor hydrolyze to generate a mixed gas containing ammonia gas, the system is complex, the requirements of the auxiliary pipelines for heat preservation and heat tracing are high, and the pipelines are prone to crystallization blockage and valve corrosion. The above two ammonia preparation technologies need a large amount of heat source, the system operation and maintenance cost is high, and to some extent, the engineering application of the technology is restricted. The urea direct injection pyrolysis technology sprays the urea solution into the flue, and utilizes the high-temperature flue gas (350-600 degrees) in the flue to pyrolyze the urea solution to generate a mixed gas containing ammonia gas for use in the downstream SCR reactor, and the system is simple and convenient to operate.

[0004] The traditional urea direct injection pyrolysis system metering and distribution module adopts a pry-mounted mode, each spray gun corresponds a set of urea solution and compressed air metering and distribution module, and each spray gun urea solution pipeline cannot be configured to be washed by washing water, so that the urea solution pipeline is prone to blockage; after the urea solution is mixed with dilution water in the distribution module, the concentration of the urea solution of each spray gun cannot be determined, so that the ammonia gas after the urea solution is pyrolyzed in the flue is prone to unevenly distribute on the surface of the catalyst; meanwhile, the nitrogen oxide at the SCR inlet flue of the gas turbine unit is small, the urea solution consumption is small, the urea solution distributed to each spray gun is smaller, and the currently used regulating valve cannot achieve precise regulation. SUMMARY

[0005] This section is intended to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification of the present application to avoid obscuring the purpose of this section, the abstract and the title, and such simplifications or omissions cannot be used to limit the scope of the present application.

[0006] In view of the above problems existing in the prior art high-efficiency urea direct injection pyrolysis system, the present application is proposed.

[0007] Therefore, the present application aims to provide a high-efficiency urea direct injection pyrolysis system, which aims to solve the problems of urea solution blocking the delivery pipeline, poor mixing of urea solution output by the spray gun, poor adjustment, etc.

[0008] To solve the above technical problems, the present application provides the following technical solutions: a high-efficiency urea direct injection pyrolysis system, which comprises a mixing unit, a metering output unit, a flushing water unit, and a compressed air unit, wherein the mixing unit comprises a urea solution supply pipeline, a desalted water supply pipeline, and a mixed solution supply pipeline connected to the output ends of the urea solution supply pipeline and the desalted water supply pipeline; the metering output unit is connected to the mixed solution supply pipeline and comprises a plurality of metering output pipelines and a return pipeline connected thereto, and the output end of each metering output pipeline is connected to a corresponding spray gun in the spray gun system; the flushing water unit has an input end connected to the desalted water supply pipeline and an output end connected to the metering output pipeline; and the compressed air unit comprises an atomizing air pipeline and a cooling air pipeline, and the output ends of the two pipelines are respectively connected to the second input end and the third input end of the spray gun.

[0009] As a preferred scheme of the high-efficiency urea direct injection pyrolysis system, the urea solution supply pipeline comprises a urea storage tank, a urea delivery pipeline connected to the urea storage tank, and a delivery control valve, a delivery filter, a urea solution delivery pump, a urea delivery pressure gauge, a urea solution regulating valve, and an electromagnetic flowmeter connected in sequence to the urea delivery pipeline.

[0010] As a preferred scheme of the high-efficiency urea direct injection pyrolysis system, the desalted water supply pipeline comprises a desalted water storage tank, a desalted water delivery pipeline connected to the desalted water storage tank, and a desalted water control valve, a desalted water delivery pump, a desalted water delivery pressure gauge, a desalted water regulating valve, and an electromagnetic flowmeter connected in sequence to the desalted water delivery pipeline.

[0011] As a preferred scheme of the high-efficiency urea direct injection pyrolysis system, the mixed solution supply pipeline comprises a mixed solution main pipeline and a mixer, a main pipeline control valve, a main pipeline pressure gauge, a main pipeline filter, and a mixed solution blowdown valve connected in the mixed solution main pipeline; and the output ends of the urea delivery pipeline and the desalted water delivery pipeline are connected to the input end of the mixed solution main pipeline.

[0012] As a preferred scheme of the high-efficiency urea direct-injection pyrolysis system, the input end of the metering output pipeline is connected to the mixed liquid main pipeline after the output port of the main pipeline filter, and the output end is connected to the first input end of the spray gun; the metering output pipeline comprises an output pipeline and, connected in sequence in the output pipeline, a urea solution electromagnetic valve, a check valve, a gear pump, an output pipeline blowdown valve, an output pipeline first pressure gauge, a mass flowmeter, a manual pressure regulating valve, an output pipeline second pressure gauge, a reversing valve and an output pipeline filter.

[0013] As a preferred scheme of the high-efficiency urea direct-injection pyrolysis system, the reflux pipeline comprises a reflux pipeline and, connected to the reflux pipeline, a check valve and a reflux pipeline electromagnetic valve; the input end of the reflux pipeline is connected to the output end of the reversing valve, and the output end is connected to the input end of the output pipeline.

[0014] As a preferred scheme of the high-efficiency urea direct-injection pyrolysis system, the flushing water unit comprises a flushing water main pipeline, a plurality of flushing water branch pipelines connected to the flushing water main pipeline, and a flushing water blowdown valve connected to the output end of the flushing water main pipeline; a flushing water main pipeline control valve is connected in the flushing water main pipeline; the output end of the flushing water branch pipeline is connected to the output pipeline between the check valve and the gear pump, and a flushing water electromagnetic valve is installed in the flushing water branch pipeline.

[0015] As a preferred scheme of the high-efficiency urea direct-injection pyrolysis system, the atomizing air pipeline comprises a compressed air source, an atomizing air main pipeline connected to the output end of the compressed air source, and a plurality of atomizing air branch pipelines connected to the atomizing air main pipeline.

[0016] As a preferred scheme of the high-efficiency urea direct-injection pyrolysis system, the atomizing air main pipeline comprises, connected in sequence from the input end to the output end, an atomizing air main pipeline filter, an atomizing air main pipeline control valve, a filter pressure-reducing three-way fitting for gas, an atomizing air main pipeline pressure gauge and an atomizing air main pipeline blowdown valve; the atomizing air branch pipeline comprises, connected in sequence from the input end to the output end, an atomizing air branch pipeline control valve, a manual pressure regulating valve, an atomizing air branch pipeline pressure gauge, an atomizing air branch pipeline float flowmeter, an atomizing air branch pipeline filter, and the output end of the atomizing air branch pipeline is connected to the second input end of the spray gun.

[0017] As a preferred scheme of the high-efficiency urea direct-injection pyrolysis system, the cooling air pipeline comprises a cooling air main pipeline and a plurality of cooling air branch pipelines connected to the cooling air main pipeline; the input end of the cooling air main pipeline is connected to the atomizing gas main pipeline at the output end of the atomizing gas main pipeline filter, and the cooling air main pipeline is further connected with a cooling air main pipeline control valve and a cooling air main pipeline discharge valve; the output end of the cooling air branch pipeline is connected to the third input end of the spray gun, and the cooling air branch pipeline is further connected with a cooling air branch pipeline control valve and a cooling air branch pipeline float flow meter in sequence; the cooling air branch pipeline is further connected with a branch pipeline, and the output end of the branch pipeline is connected to the fourth input end of the spray gun, and the branch pipeline is provided with a branch pipeline control valve.

[0018] The present application has the following advantages:

[0019] In the pipeline system of the present application, the concentration of the urea solution is adjusted and monitored by the mixing unit and the metering output unit in multiple stages, so that the concentration is consistent before reaching the spray gun, and the pipeline of the flushing water unit is matched to avoid the pipeline blockage problem when the pipeline system is not used or temporarily stopped. Compared with the traditional pipeline system, the distribution module is reduced, the system pipeline is simpler and more convenient, and the cooperation of the vector pump and the mass flow meter makes the control and adjustment of the urea solution in the spray gun more rapid and accurate. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor. Among them:

[0021] Figure 1 It is a schematic diagram of the overall pipeline frame of the high-efficiency urea direct-injection pyrolysis system of the present application.

[0022] Figure 2 It is a schematic diagram of the urea solution supply pipeline structure of the high-efficiency urea direct-injection pyrolysis system of the present application.

[0023] Figure 3 It is a schematic diagram of the desalted water supply pipeline structure of the high-efficiency urea direct-injection pyrolysis system of the present application.

[0024] Figure 4 It is a schematic diagram of the mixed liquid supply pipeline structure of the high-efficiency urea direct-injection pyrolysis system of the present application.

[0025] Figure 5 It is a schematic diagram of the metering output unit structure of the high-efficiency urea direct-injection pyrolysis system of the present application.

[0026] Figure 6 The structure diagram of the flushing water unit of the high-efficiency urea direct injection pyrolysis system.

[0027] Figure 7 The structure diagram of the compressed air unit of the high-efficiency urea direct injection pyrolysis system.

[0028] Figure 8 The structure diagram of the overall pipeline connection of the high-efficiency urea direct injection pyrolysis system. DETAILED DESCRIPTION

[0029] In order to make the above objectives, characteristics and advantages of the present application more apparent, specific embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0030] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without the specific details given herein. In other instances, well-known methods have not been described in detail in order to avoid unnecessarily obscuring the present application.

[0031] Secondly, the "one embodiment" or "embodiment" referred to herein can include specific features, structures or characteristics contained in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0032] Thirdly, the present application is described in detail in conjunction with the schematic diagram. In the detailed description of the embodiments of the present application, the cross-sectional view of the device structure is partially enlarged without the general proportion for the convenience of description, and the schematic diagram is only an example, which should not limit the scope of protection of the present application. In addition, the three-dimensional spatial dimensions of length, width and depth should be included in the actual manufacture.

[0033] Embodiment 1

[0034] Reference Figure 1 and 8 For the first embodiment of the present application, a high-efficiency urea direct injection pyrolysis system is provided, which includes a mixing unit 100, a metering output unit 200, a flushing water unit 300 and a compressed air unit 400. The mixing unit 100 is used for mixing urea solution and desalted water to prepare a preset urea solution concentration. The metering output unit 200 is used to monitor the urea solution concentration in the input spray gun corresponding to each spray gun system, so as to facilitate the adjustment of the spray gun. The flushing water unit 300 is used for cleaning each pipeline to avoid pipeline blockage. The compressed air unit 400 is used to cool the spray gun pipeline and prevent the urea solution from being evaporated in the spray gun pipeline.

[0035] Specifically, the mixing unit 100, which includes a urea solution supply pipeline 101, a desalted water supply pipeline 102 and a mixed solution supply pipeline 103 connected to the output ends of the urea solution supply pipeline 101 and the desalted water supply pipeline 102; wherein the urea solution supply pipeline 101 provides the initial urea solution, the desalted water supply pipeline 102 provides the initial desalted water, both of which are mixed in the mixed solution supply pipeline 103, and are diluted to prepare the urea solution of the required concentration, and are output to the metering output unit 200.

[0036] The metering output unit 200 is connected to the mixed solution supply pipeline 103, which includes a plurality of metering output pipelines 201 and a return pipeline 202 connected thereto, and the output end of each metering output pipeline 201 is connected to the corresponding spray gun P in the spray gun system; wherein each group of metering output pipelines 201 is connected to the corresponding spray gun system, and the corresponding return pipeline 202 is also connected, and the output end of the metering output pipeline 201 is connected to the spray gun P to provide the urea solution for the corresponding spray gun P, and the pipeline is provided with a vector pump and a mass flow meter that can cooperate to provide the urea solution with accurate flow rate and concentration for the corresponding spray gun system.

[0037] The flushing water unit 300 is connected to the desalted water supply pipeline 102 at the input end and to the metering output pipeline 201 at the output end; wherein the flushing water in this unit is obtained from the desalted water supply pipeline 102, of course, a separate water source for flushing can also be provided.

[0038] The compressed air unit 400 includes an atomizing air pipeline 401 and a cooling air pipeline 402, and the output ends of the two pipelines are respectively connected to the second input end and the third input end of the spray gun P. Wherein the atomizing air pipeline 401 is used to atomize the urea solution into the flue, and the cooling air pipeline 402 is used to dilute the heat of the spray gun in the flue to prevent the urea solution from being evaporated dry in the spray gun pipeline.

[0039] Example 2

[0040] Reference Figures 2-8 For the second embodiment of the present application, which is different from the first embodiment: the urea solution supply pipeline 101 includes a urea storage tank 101a, a urea conveying pipeline 101b connected to the urea storage tank 101a, and a conveying control valve 101c, a conveying filter 101d, a urea solution conveying pump 101e, a urea conveying pressure gauge 101f, a urea solution regulating valve 101g and an electromagnetic flowmeter D connected in sequence in the urea conveying pipeline 101b.

[0041] Specifically, the urea storage tank 101a stores high-concentration urea solution or urea preparation raw material. In this embodiment, a 50% concentration urea solution is taken as an example for illustration. The urea delivery pipeline 101b is connected to the urea storage tank 101a and the mixer 103b in the mixed solution supply pipeline 103, for delivering urea raw material to the mixer 103b as needed. The delivery control valve 101c installed in the pipeline is used to control the on-off of the delivery pipeline. The delivery filter 101d is used to filter out impurities that may exist in the urea raw material, so as to keep the output urea pure. The urea solution delivery pump 101e provides driving force for urea solution delivery in the pipeline. The urea delivery pressure gauge 101f is used to monitor the pressure in the delivery pipeline. The urea solution regulating valve 101g is used to regulate the flow of the urea solution output by the urea delivery pipeline 101b. The electromagnetic flowmeter D monitors and displays the flow value of the output urea solution. The urea solution regulating valve 101g can be intuitively adjusted according to the monitoring value.

[0042] Further, the desalted water supply pipeline 102 includes a desalted water storage tank 102a, a desalted water delivery pipeline 102b connected to the desalted water storage tank 102a, and a desalted water control valve 102c, a desalted water delivery pump 102d, a desalted water delivery pressure gauge 102e, a desalted water regulating valve 102f, and an electromagnetic flowmeter D connected to the desalted water delivery pipeline 102b in sequence.

[0043] The desalted water is stored in the desalted water storage tank 102a. It should be noted that the storage tank is not limited to a tank, but can also be other types of storage. The desalted water delivery pipeline 102b is connected to the desalted water storage tank 102a and the mixer 103b in the mixed solution supply pipeline 103, for delivering desalted water to the mixer 103b as needed. The desalted water control valve 102c installed in the pipeline is used to control the on-off of the desalted water delivery pipeline 102b. The desalted water delivery pump 102d is used to provide driving force required for liquid pumping. The desalted water delivery pressure gauge 102e is used to monitor the pressure in the delivery pipeline. The desalted water regulating valve 102f is used to regulate the flow of the desalted water output by the desalted water delivery pipeline 102b. The electromagnetic flowmeter D monitors and displays the flow value of the output desalted water, and the desalted water regulating valve 102f can be intuitively adjusted according to the monitoring value.

[0044] The mixed solution supply pipeline 103 includes a mixed solution main pipeline 103a and a mixer 103b connected to the mixed solution main pipeline 103a, a main pipeline control valve 103c, a main pipeline pressure gauge 103d, a main pipeline filter 103e, and a mixed solution blowdown valve 103f. The output ends of the urea delivery pipeline 101b and the desalted water delivery pipeline 102b are connected to the input end of the mixed solution main pipeline 103a.

[0045] The mixed solution main pipeline 103a is a main pipeline for supplying the mixed and diluted urea solution and is connected with each group of metering output pipelines 201. The input end of the mixed solution main pipeline 103a is connected with the output end of the urea conveying pipeline 101b and the desalted water conveying pipeline 102b respectively to receive the two kinds of medium raw materials and is merged into the mixer 103b to be mixed. In this embodiment, a two-stage mixer is adopted, which is divided into a first mixer and a second mixer. The amount of desalted water is adjusted in real time according to the flow of the urea solution. Finally, the low-concentration urea solution required is prepared in the mixer 103b and is conveyed to the output end of the mixed solution main pipeline 103a.

[0046] The output side of the mixer 103b in the mixed solution main pipeline 103a is provided with a main pipeline control valve 103c for controlling the opening and closing of the pipeline, a main pipeline pressure gauge 103d for monitoring the pressure in the pipeline, a main pipeline filter 103e for filtering and removing impurities existing in the pipeline and a mixed solution blowdown valve 103f for discharging flushing liquid or waste mixed solution in the main pipeline. It should be noted that the main pipeline control valve 103c and the main pipeline filter 103e can be provided with multiple valves according to requirements, which will not be described in detail here.

[0047] The input end of the metering output pipeline 201 is connected to the mixed solution main pipeline 103a after the output end of the main pipeline filter 103e, and the output end is connected to the first input end of the spray gun P. The metering output pipeline 201 comprises an output pipeline 201a and a urea solution electromagnetic valve 201b, a check valve N, a gear pump 201c, an output pipeline blowdown valve 201d, an output pipeline first pressure gauge 201e, a mass flowmeter 201f, a first manual pressure regulating valve 201g, an output pipeline second pressure gauge 201h, a reversing valve 201j and an output pipeline filter 201k connected in sequence in the output pipeline 201a.

[0048] Specifically, the metering output pipeline 201 is connected with the mixed solution main pipeline 103a and the spray gun system. The output pipeline 201a is the main connecting pipeline. The urea solution electromagnetic valve 201b provided in the pipeline is used to control the opening and closing of the pipeline, and the check valve N is used to prevent the backflow of the urea solution. The gear pump 201c is used to accurately adjust the output amount of the urea solution to the spray gun P. The output pipeline blowdown valve 201d is used to discharge flushing water when the metering output pipeline 201 is cleaned. The output pipeline first pressure gauge 201e is used to monitor the pressure in the pipeline before the flow to the mass flowmeter 201f. The first manual pressure regulating valve 201g is used for further pressure regulation in the pipeline. The output pipeline second pressure gauge 201h is used to monitor the pressure in the pipeline after the pressure is regulated twice. The purpose is to ensure that the pressure and concentration of the urea solution in the input spray gun system meet the predetermined requirements. The reversing valve 201j is used to adjust the flow direction of the pipeline, that is, whether the flow is to the spray gun P through the output pipeline filter 201k or to the return pipeline 202.

[0049] Further, the return pipeline 202 includes a return pipeline 202a, a check valve N and a return pipeline electromagnetic valve 202b connected to the return pipeline 202a; the input end of the return pipeline 202a is connected to the output end of the switching valve 201j, and the output end is connected to the input end of the output pipeline 201a.

[0050] The return pipeline 202 is used for the circulation of the urea solution when the spray gun system is temporarily stopped to prevent condensation and blockage in the pipeline system. The check valve N in the return pipeline 202a is used to maintain one-way flow of the urea solution in the pipeline; the return pipeline electromagnetic valve 202b is used to control the opening and closing of the return pipeline 202a.

[0051] The flushing water unit 300 includes a flushing water main pipeline 301, a plurality of flushing water branch pipelines 302 connected to the flushing water main pipeline 301, and a flushing water discharge valve 303 connected to the output end of the flushing water main pipeline 301; a flushing water main pipeline control valve 301a is connected in the flushing water main pipeline 301; the output end of the flushing water branch pipeline 302 is connected to the output pipeline 201a between the check valve N and the urea solution electromagnetic valve 201b, and a flushing water electromagnetic valve 302a is installed in the flushing water branch pipeline 302.

[0052] Specifically, the flushing water main pipeline 301 takes water from the desalted water storage tank 102a or the desalted water delivery pipeline 102b, controls the opening and closing of the pipeline through the flushing water main pipeline control valve 301a connected in the pipeline, and discharges the flushing water remaining in the pipeline through the flushing water discharge valve 303; the flushing water branch pipeline 302 takes water from the flushing water main pipeline 301 and is used for flushing operation of each metering output pipeline 201; the opening and closing of the flushing water branch pipeline 302 is controlled by the flushing water electromagnetic valve 302a.

[0053] The atomizing air pipeline 401 includes a compressed air source 401a, an atomizing air main pipeline 401b connected to the output end of the compressed air source 401a, and a plurality of atomizing air branch pipelines 401c connected to the atomizing air main pipeline 401b.

[0054] Further, the atomizing air main pipeline 401b is sequentially connected in the direction from the input end to the output end with an atomizing air main pipeline filter 401b-1, an atomizing air main pipeline control valve 401b-2, a filter pressure reducing three-way joint for air 401b-3, an atomizing air main pipeline pressure gauge 401b-4, and an atomizing air main pipeline discharge valve 401b-5; the atomizing air branch pipeline 401c is sequentially connected in the direction from the input end to the output end with an atomizing air branch pipeline control valve 401c-1, a second manual pressure regulating valve 401c-2, an atomizing air branch pipeline pressure gauge 401c-3, an atomizing air branch pipeline float flowmeter 401c-4, an atomizing air branch pipeline filter 401c-5, and the output end of the atomizing air branch pipeline 401c is connected to the second input end of the spray gun P.

[0055] The compressed air source 401a can be in the form of a compressed air tank or supplied by a compressor, which is not limited herein; the atomizing air main pipeline 401b is connected with the compressed air source 401a to output compressed air, and the atomizing air branch pipeline 401c is connected with the atomizing air main pipeline 401b to supply compressed air to the corresponding connected spray gun P according to the requirement.

[0056] In the atomizing air main pipeline 401b, the atomizing air main filter 401b-1 is used to filter impurities in the compressed air to avoid affecting the spray gun P; the atomizing air main control valve 401b-2 is used to control the on-off of the atomizing air main pipeline 401b; the filter pressure reducing three-way joint 401b-3 is used to reduce and filter the compressed air to meet the use requirement; the atomizing air main pressure gauge 401b-4 is used to monitor the pipeline pressure in the atomizing air main pipeline 401b; and the atomizing air main discharge valve 401b-5 is used for discharge pressure relief of the atomizing air main pipeline 401b.

[0057] Further, the atomizing air branch control valve 401c-1 in the atomizing air branch pipeline 401c is used to control the on-off of the atomizing air branch pipeline 401c; the second manual pressure regulating valve 401c-2 is used to finely adjust the exhaust rate of the atomizing air branch pipeline 401c to meet the use requirement; the atomizing air branch pressure gauge 401c-3 is used to monitor the pressure value in the atomizing air branch pipeline 401c; the atomizing air branch float flowmeter 401c-4 is used to monitor the flow size of the atomizing air in the pipeline; and the atomizing air branch filter 401c-5 is used to filter the compressed air in the atomizing air branch pipeline 401c to minimize the influence of impurities on the spray gun P.

[0058] Further, the cooling air pipeline 402 includes a cooling air main pipeline 402a and a plurality of cooling air branch pipelines 402b connected to the cooling air main pipeline 402a; the input end of the cooling air main pipeline 402a is connected to the atomizing air main pipeline 401b at the output port of the atomizing air main filter 401b-1, and the pipeline is further connected with a cooling air main control valve 402a-1 and a cooling air main discharge valve 402a-2; the output end of the cooling air branch pipeline 402b is connected to the third input end of the spray gun P, and the pipeline is sequentially connected with a cooling air branch control valve 402b-1 and a cooling air branch float flowmeter 402b-2; the cooling air branch pipeline 402b is further connected with a branch pipeline 402b-3, and the output end of the branch pipeline 402b-3 is connected to the fourth input end of the spray gun P, and the pipeline is provided with a branch control valve F.

[0059] The main cooling air duct 402a is connected to multiple branch cooling air ducts 402b. The main cooling air duct 402a draws compressed air from the compressed air source 401a or the atomizing air main duct 401b and delivers it to each branch duct. In the main cooling air duct 402a, a main cooling air exhaust valve 402a-1 controls the opening and closing of the duct. In the branch cooling air ducts 402b, a branch cooling air control valve 402b-1 controls the opening and closing of the branch cooling air ducts 402b. A branch cooling air float flow meter 402b-2 monitors the flow rate of gas in the branch cooling air ducts 402b.

[0060] Furthermore, branch pipe 402b-3 is connected to the fourth input end of spray gun P, which is used to open branch pipe 402b-3 when spray gun P is taken out for maintenance online, to provide sealing air for convenient maintenance.

[0061] The remaining structure is the same as that in Example 1.

[0062] In summary, the contents of Examples 1 and 2 above, and with reference to the appendix, Figures 1-8 As shown, during the operation of this pipeline system, the urea solution raw material and demineralized water are first mixed to prepare a urea solution of a predetermined concentration. For the urea solution supply pipeline 101, the delivery control valve 101c, the urea solution delivery pump 101e, and the urea solution regulating valve 101g are opened to pump the urea solution raw material into the mixer 103b. For the demineralized water supply pipeline 102, the demineralized water control valve 102c, the demineralized water delivery pump 102d, and the demineralized water regulating valve 102f are opened, and the demineralized water is also pumped into the mixer 103b for mixing. According to the prepared concentration, the urea solution regulating valve 101g and the demineralized water regulating valve 102f are adjusted respectively to prepare the urea solution mixture of the required concentration in the mixer 103b, and then the mixture is pumped into the main pipeline 103a.

[0063] The main pipeline 103a of the mixed liquid is connected to several metering output units 200 and their corresponding spray gun systems. When a certain spray gun P needs to be opened, the urea solution solenoid valve 201b in the corresponding output pipeline 201a is opened, the gear pump 201c is turned on and adjusted to the maximum Hertz, the flow rate is read by the mass flow meter 201f, the first manual pressure regulating valve 201g is adjusted to the maximum opening, and the reversing valve 201j is switched to the direction of the spray gun P. The mixed liquid enters the output pipeline 201a and is sprayed into the flue through the output pipe filter 201k.

[0064] Furthermore, the required amount of urea is calculated based on the changes in nitrogen oxide inlet and outlet of the flue gas inlet of the gas-fired waste heat boiler, and the Hertz value of the gear pump 201c is adjusted in real time based on the measurement value of the mass flow meter 201f to achieve precise adjustment.

[0065] When the lance P is temporarily disabled, the switching valve 201j is switched to the backflow pipe 202a direction, the backflow pipe electromagnetic valve 202b is opened, and the mixed solution circulates in the output pipe 201a and the backflow pipe 202a; when the lance P is used again, the switching valve 201j is switched to the lance input direction, and the backflow pipe electromagnetic valve 202b is closed, so that the mixed solution always flows and does not cause problems such as deposition and blockage in the backflow pipe 202 and the backflow pipe 202.

[0066] When the lance system is taken out of use, the urea solution electromagnetic valve 201b is closed, the flushing water main pipe control valve 301a is opened, and the gear pump 201c is opened to the maximum, so that the pipe between the urea solution electromagnetic valve 201b and the lance can be flushed, after a certain time of flushing, the switching valve 201j is switched to the backflow pipe 202a direction, the backflow pipe electromagnetic valve 202b is opened, and the output pipe blowdown valve 201d can flush the backflow pipe 202a.

[0067] Further, the control valve of each metering output unit 200 is closed, the urea solution delivery pump 101e and the urea solution regulating valve 101g in the urea solution supply pipe 101 are closed, only the desalted water supply pipe 102 is connected to the mixed solution supply pipe 103, and the mixed solution blowdown valve 103f is opened, so that the mixed solution supply pipe 103 can be flushed.

[0068] When the urea solution pipe system is put into use and the lance P is opened, the atomizing air pipe 401 is opened synchronously, the atomizing gas main pipe control valve 401b-2 and the atomizing gas branch pipe control valve 401c-1 are opened, the manual pressure regulating valve 401c-2 is adjusted to make the gas pressure and flow rate in a proper range, the compressed air enters the lance P through the atomizing gas branch pipe filter 401c-5 to atomize the urea solution into the flue; in order to prevent the urea solution in the lance pipe from being evaporated by the high-temperature flue gas in the flue, the cooling gas pipe 402 needs to be opened, that is, the cooling air main pipe control valve 402a-1 and the cooling air branch pipe control valve 402b-1 are opened, so that the cooling air enters the outer ring of the urea solution pipe of the lance to cool and absorb the heat received by the urea solution in the lance, thereby preventing the urea solution from being evaporated in the lance pipe.

[0069] When the lance P is taken out of use for maintenance, the cooling gas pipe 402 is opened, and the branch pipe control valve F is opened to provide sealing air for facilitating maintenance.

[0070] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application but not limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and all of them should be covered in the scope of the claims of the present application.

Claims

1. A high efficiency urea direct injection pyrolysis system characterized by: The utility model relates to a kind of urea solution preparation systems, comprising, Mixing unit (100), including urea solution supply line (101), desalted water supply line (102) and the mixing liquid supply line (103) connected to the output end of the urea solution supply line (101) and desalted water supply line (102); Metering output unit (200) is connected with the mixing liquid supply line (103), and it includes several metering output lines (201) and return line (202) connected thereto, and the output end of each metering output line (201) is connected with the corresponding spray gun (P) in spray gun system; Rinse water unit (300), the input end is connected with desalted water supply line (102), and the output end is connected with metering output line (201);And, Compressed air unit (400) includes atomizing air line (401) and cooling air line (402), and the output end of the two lines is connected with the second input end, third input end of the spray gun (P) respectively; The metering output line (201) includes output pipe (201a) and sequentially connected in the urea solution solenoid valve (201b), check valve (N), gear pump (201c), output pipe blowdown valve (201d), output pipe first pressure gauge (201e), mass flowmeter (201f), first manual pressure regulating valve (201g), output pipe second pressure gauge (201h), reversing valve (201j) and output pipe filter (201k) of the output pipe (201a); The return line (202) includes return pipe (202a) and check valve (N) and return pipe solenoid valve (202b) connected to the return pipe (202a); The input end of the return pipe (202a) is connected with the output end of the reversing valve (201j), and the output end is connected with the input end of the output pipe (201a).

2. The efficient urea direct injection pyrolysis system of claim 1, wherein: The urea solution supply line (101) includes urea storage tank (101a), urea conveying pipe (101b) connected to the urea storage tank (101a) and conveying control valve (101c), conveying filter (101d), urea solution conveying pump (101e), urea conveying pressure gauge (101f), urea solution regulating valve (101g), electromagnetic flowmeter (D) sequentially connected in the urea conveying pipe (101b).

3. The efficient urea direct injection pyrolysis system of claim 2, wherein: The desalted water supply line (102) includes desalted water storage tank (102a), desalted water conveying pipe (102b) connected to the desalted water storage tank (102a) and desalted water control valve (102c), desalted water conveying pump (102d), desalted water conveying pressure gauge (102e), desalted water regulating valve (102f), electromagnetic flowmeter (D) sequentially connected in the desalted water conveying pipe (102b).

4. The efficient urea direct injection pyrolysis system of claim 3, wherein: The mixed solution supply pipeline (103) comprises a mixed solution main pipeline (103a) and a mixer (103b), a main pipeline control valve (103c), a main pipeline pressure gauge (103d), a main pipeline filter (103e) and a mixed solution blowdown valve (103f) connected in the mixed solution main pipeline (103a); The output ends of the urea delivery pipeline (101b) and the desalted water delivery pipeline (102b) are connected to the input end of the mixed solution main pipeline (103a).

5. The efficient urea direct injection pyrolysis system of claim 4, wherein: The input end of the metering output pipeline (201) is connected to the mixed solution main pipeline (103a) after the output end of the main pipeline filter (103e), and the output end is connected to the first input end of the spray gun (P).

6. The efficient urea direct injection pyrolysis system of claim 5, wherein: The flushing water unit (300) comprises a flushing water main pipeline (301), a plurality of flushing water branch pipelines (302) connected to the flushing water main pipeline (301), and a flushing water discharge valve (303) connected to the output end of the flushing water main pipeline (301); The flushing water main pipeline (301) is connected with a flushing water main pipeline control valve (301a); The output end of the flushing water branch pipeline (302) is connected to the output pipeline (201a) between the check valve (N) and the urea solution electromagnetic valve (201b), and the flushing water branch pipeline (302) is provided with a flushing water electromagnetic valve (302a).

7. The efficient urea direct injection pyrolysis system of claim 6, wherein: The atomizing air pipeline (401) comprises a compressed air source (401a), an atomizing air main pipeline (401b) connected to the output end of the compressed air source (401a), and a plurality of atomizing air branch pipelines (401c) connected to the atomizing air main pipeline (401b).

8. The efficient urea direct injection pyrolysis system of claim 7, wherein: The atomizing air main pipeline (401b) is sequentially connected with an atomizing air main pipeline filter (401b-1), an atomizing air main pipeline control valve (401b-2), a filter pressure-reducing three-way joint for air (401b-3), an atomizing air main pipeline pressure gauge (401b-4) and an atomizing air main pipeline discharge valve (401b-5) from the input end to the output end; The atomizing air branch pipeline (401c) is sequentially connected with an atomizing air branch pipeline control valve (401c-1), a second manual pressure regulating valve (401c-2), an atomizing air branch pipeline pressure gauge (401c-3), an atomizing air branch pipeline float flowmeter (401c-4), an atomizing air branch pipeline filter (401c-5) from the input end to the output end, and the output end of the atomizing air branch pipeline (401c) is connected to the second input end of the spray gun (P).

9. The efficient urea direct injection pyrolysis system of claim 8, wherein: The cooling air pipeline (402) comprises a cooling air main pipeline (402a) and a plurality of cooling air branch pipelines (402b) connected to the cooling air main pipeline (402a); The input end of the cooling air main pipeline (402a) is connected to the atomizing air main pipeline (401b) at the output end of the atomizing air main pipeline filter (401b-1), and the pipeline is further connected with a cooling air main pipeline control valve (402a-1) and a cooling air main pipeline discharge valve (402a-2); The output end of the cooling air sub-pipe (402b) is connected to the third input end of the spray gun (P), and a cooling air sub-pipe control valve (402b-1) and a cooling air sub-pipe float flow meter (402b-2) are sequentially connected in the pipe; A branch pipe (402b-3) is further connected to the cooling air sub-pipe (402b), and the output end of the branch pipe (402b-3) is connected to the fourth input end of the spray gun (P), and a branch pipe control valve (F) is arranged in the pipe.

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