Solid waste blending combustion boiler flue gas SCR denitration system and CFB boiler system

Abstract

The utility model provides a solid waste blending combustion boiler flue gas SCR denitration system and a CFB boiler system, comprising: a heat exchange flue provided with a bypass windshield valve, the bypass windshield valve divides the heat exchange flue into a first heat exchange area and a second heat exchange area, the temperature of the first heat exchange area being greater than the temperature of the second heat exchange area; an SCR inlet flue of the SCR reactor is communicated with the first heat exchange area, an SCR outlet flue of the SCR reactor is communicated with the second heat exchange area, an SCR inlet windshield valve is arranged in the SCR inlet flue, and an SCR outlet windshield valve is arranged in the SCR outlet flue. According to the utility model, only when the upstream denitration device cannot meet the emission requirement, the SCR reactor is utilized for further denitration treatment so as to ensure that the flue gas emission reaches the standard; when the upstream denitration device can meet the emission requirement, the flue gas can be directly discharged after heat exchange through the heat exchange flue and does not need to pass through an SCR reactor, unnecessary contact between the catalyst module and the flue gas and dust is reduced, and the service life of the catalyst is prolonged.

Description

Technical Field

[0001] The utility model belongs to the technical field of environmental protection equipment, and particularly relates to a solid waste mixed combustion boiler flue gas SCR denitration system and a CFB boiler system. Background Art

[0002] In order to improve the effect of energy conservation and emission reduction, the use of industrial boilers to burn solid waste has become a new development trend. The proportion of solid waste burning boilers has gradually increased, especially solid waste burning CFB (circulating fluidized bed boiler) boilers. Since the calorific value of solid waste is generally relatively low and the water content is high, the original NOx of CFB boilers will be reduced after burning solid waste, which is beneficial to NOx control. However, due to the complex composition and diverse sources of solid waste, it is easy to cause large fluctuations in NOx concentration in solid waste burning CFB boilers, the reduction of boiler outlet flue gas temperature does not meet the SNCR (selective non-catalytic reduction) denitrification requirements, the substantial increase of alkaline metals and heavy metals in smoke leads to SCR blockage, catalyst poisoning and deactivation, and post-combustion causes catalyst sintering and other problems, making it impossible for the solid waste burning boiler flue gas SCR denitrification system to operate stably and reliably for a long time, frequent failures, greatly reduced catalyst life, and unguaranteed denitrification efficiency. It is not only difficult to achieve ultra-low emissions of flue gas, but also affects the operation of the boiler, forcing the boiler to shut down.

[0003] The existing flue gas denitrification system of solid waste mixed combustion CFB boiler is equipped with a low nitrogen combustion system, which is used to reduce the NOx concentration from the original end through air classification and other means; it can basically control the NOx concentration at 150mg / Nm 3 At the same time, SNCR denitrification is installed at the inlet of the cyclone separator of the CFB boiler, that is, an SNCR denitrification system is added between the furnace and the cyclone separator of the CFB boiler. Under the high load condition of the CFB boiler (more than 50-70% load), the inlet temperature of the cyclone separator is 800℃~950℃, which is the best reaction temperature of SNCR. At the same time, the flue gas swirl in the cyclone separator further enhances the mixing and reaction time of ammonia and flue gas. At this time, the SNCR denitrification efficiency can reach about 70-80%. For this reason, under normal high load conditions, NOx emissions <50mg / Nm can be achieved only through low-nitrogen combustion + SNCR denitrification. 3 , meeting ultra-low emission requirements.

[0004] However, when the boiler is under low load of 50-70%, the SNCR efficiency will be greatly reduced due to the decrease in the inlet temperature of the cyclone separator. In order to ensure emissions, a layer of SCR (Selective Catalytic Reduction) denitrification device will be embedded in the temperature range of 300-400℃ on the rear heating surface, and the high denitrification efficiency of SCR denitrification will be used to achieve the ultimate ultra-low emissions. For this reason, the flue gas denitrification system of existing CFB boilers generally adopts a low-nitrogen combustion + SNCR + built-in SCR combined denitrification process.

[0005] Under high load, low nitrogen combustion + SNCR denitrification can meet emission requirements, but at this time, the SCR denitrification catalyst still needs to withstand the passage of flue gas and dust, which accelerates the deactivation of the catalyst, especially after the burning of solid waste, the alkali metals such as Na and K and heavy metals in the dust increase, which are not conducive to the activity of the SCR catalyst. In particular, the large increase of alkali metals and long-term unnecessary contact with these smoke dusts will cause the catalyst to deactivate quickly.

[0006] Therefore, how to extend the life of the catalyst is an urgent problem to be solved by those skilled in the art. Utility Model Content

[0007] In view of this, the purpose of the utility model is to provide a solid waste mixed combustion boiler flue gas SCR denitrification system to extend the service life of the catalyst module;

[0008] Another object of the utility model is to provide a CFB boiler system having the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system.

[0009] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0010] A solid waste mixed combustion boiler flue gas SCR denitrification system, comprising:

[0011] A heat exchange flue, the heat exchange flue comprising a first heat exchange zone and a second heat exchange zone, a bypass damper valve is provided in the heat exchange flue, the bypass damper valve is located between the first heat exchange zone and the second heat exchange zone, and the temperature of the first heat exchange zone is greater than the temperature of the second heat exchange zone;

[0012] An SCR reactor, wherein the SCR reactor is connected to the first heat exchange zone through an SCR inlet flue, and the SCR reactor is connected to the second heat exchange zone through an SCR outlet flue, an SCR inlet damper valve is arranged in the SCR inlet flue, and an SCR outlet damper valve is arranged in the SCR outlet flue.

[0013] Optionally, in the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system, the SCR inlet damper valve and the SCR outlet damper valve are controlled in linkage with the bypass damper valve;

[0014] When the SCR inlet damper valve and the SCR outlet damper valve are opened, the bypass damper valve is closed; when the SCR inlet damper valve and the SCR outlet damper valve are closed, the bypass damper valve is opened.

[0015] Optionally, the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system also includes a nitrogen oxide sensor, which is used to detect the content of nitrogen oxides in the flue gas in the first heat exchange zone. When the content of nitrogen oxides exceeds a preset content, the SCR inlet damper valve and the SCR outlet damper valve are opened, and the bypass damper valve is closed. When the content of nitrogen oxides is lower than a preset content, the SCR inlet damper valve and the SCR outlet damper valve are closed, and the bypass damper valve is opened; or,

[0016] It also includes a temperature sensor, which is used to detect the temperature of the flue gas upstream of the first heat exchange zone. When the temperature exceeds a preset temperature, the SCR inlet damper valve and the SCR outlet damper valve are closed, and the bypass damper valve is opened. When the temperature is lower than a preset temperature, the SCR inlet damper valve and the SCR outlet damper valve are opened, and the bypass damper valve is closed.

[0017] Optionally, in the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system, an interception and purge device is provided in the SCR inlet flue, and the interception and purge device is used to intercept unburned solid waste to avoid catalyst sintering.

[0018] Optionally, in the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system, the interception and purge device includes a porous interception plate and a pulse sweeper, the porous interception plate is arranged in the SCR inlet flue, and the projection of the porous interception plate on the cross section of the SCR inlet flue coincides with the cross section of the SCR inlet flue;

[0019] The pulse sweeper is used to output pulse gas to purge the surface of the porous intercepting plate.

[0020] Optionally, in the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system, the SCR inlet flue includes at least a vertical flue section, the porous intercepting plate is arranged in the vertical flue section, and the SCR inlet flue is provided with an ash hopper directly below the porous intercepting plate.

[0021] Optionally, in the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system, the angle α between the porous intercepting plate and the flue wall of the vertical flue section is not greater than 45°.

[0022] Optionally, in the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system, the pulse cleaner includes a pulse nozzle, one end of the pulse nozzle is a nozzle inlet, and the other end is a nozzle outlet, and the width of the pulse nozzle gradually increases in the direction from the nozzle inlet to the nozzle outlet;

[0023] The pulse nozzle is divided into an air inlet zone and an air outlet zone in sequence along the air inlet direction, and the height of the air outlet zone gradually decreases in the direction from the nozzle inlet to the nozzle outlet.

[0024] Optionally, in the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system, the vent holes of the porous interception plate are polygonal holes or circular holes;

[0025] The maximum side length d of the polygonal hole is 4 to 10 mm, and the distance b between two adjacent polygonal holes is 6 to 14 mm;

[0026] The diameter R of the circular hole is 4 to 10 mm, and the distance b between two adjacent circular holes is 6 to 14 mm.

[0027] Optionally, in the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system, a catalyst module and a rake-type sootblower arranged on the top of the catalyst module are provided in the SCR reactor to quickly remove dust on the catalyst surface and reduce long-term contact between the catalyst and dust.

[0028] Optionally, in the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system, the rake sootblowing device includes:

[0029] A sootblowing rake pipe is arranged on the upper part of the catalyst module, and the sootblowing rake pipe has an air injection port pointing to the catalyst module;

[0030] A driving device, used for driving the sootblowing rake pipe to move in a plane parallel to the catalyst module;

[0031] The Roots blower is connected with the soot blowing rake pipe through a soot blowing pipeline.

[0032] Optionally, in the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system, a soot blowing shut-off valve is provided on the soot blowing pipeline.

[0033] Optionally, in the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system, the soot blowing rake pipes are multiple in parallel, each of the soot blowing rake pipes is correspondingly provided with the driving device, and each of the soot blowing rake pipes is provided with the soot blowing shut-off valve which is individually controlled.

[0034] Optionally, in the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system, the rake sootblowing device also includes

[0035] an anti-blocking fan connected to the soot blowing pipeline between the soot blowing rake pipe and the soot blowing shut-off valve through an anti-blocking pipeline;

[0036] A check valve is arranged on the anti-blocking pipeline. When the sootblowing shut-off valve is closed, the check valve is opened, so that the check valve is in a conducting state in the direction from the anti-blocking fan to the sootblowing rake pipe. When the sootblowing shut-off valve is opened, the check valve is closed, so that the check valve is in a cut-off state in the direction from the anti-blocking fan to the sootblowing rake pipe.

[0037] Optionally, in the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system, a manual valve is also provided on the anti-blocking pipeline, and the manual valve is provided between the check valve and the anti-blocking fan.

[0038] The utility model provides a SCR denitrification system for flue gas from a solid waste co-combustion boiler. When the flue gas after denitration treatment by the upstream denitration device cannot meet the emission requirements, the bypass damper valve is closed, and the SCR inlet damper valve and the SCR outlet damper valve are opened. The high-temperature flue gas passes through the first heat exchange zone of the heat exchange flue, exchanges heat with the heat exchange device in the first heat exchange zone, and reduces the flue gas temperature to 300°C to 400°C. Then, the flue gas is introduced into the SCR reactor through the SCR inlet flue of the SCR reactor. The NOx in the flue gas and the ammonia escaping from the upstream denitration device undergo a denitration reaction under the catalytic action of the catalyst module in the SCR reactor, and the NOx is reduced to nitrogen and water. The flue gas after denitration is connected to the second heat exchange zone of the heat exchange flue through the SCR outlet flue for further heat exchange.

[0039] When the flue gas after denitration treatment by the upstream denitration device can meet the emission requirements, the bypass damper valve is opened, the SCR inlet damper valve and the SCR outlet damper valve are closed, and the SCR reactor is bypassed; the high-temperature flue gas is discharged after heat exchange by the heat exchange devices in the first heat exchange zone and the second heat exchange zone of the heat exchange flue. The utility model uses the SCR reactor for further denitration treatment only when the upstream denitration device cannot meet the emission requirements to ensure that the flue gas emissions meet the standards; when the upstream denitration device can meet the emission requirements, the flue gas can be discharged directly after heat exchange through the heat exchange flue without passing through the SCR reactor, thereby reducing unnecessary contact between the catalyst module and the flue gas and dust, and extending the life of the catalyst.

[0040] A CFB boiler system, comprising:

[0041] Boiler body;

[0042] a cyclone separator, connected to the flue gas outlet of the boiler body;

[0043] An SNCR denitration module is arranged in the flue between the cyclone separator and the boiler body;

[0044] A solid waste co-firing boiler flue gas SCR denitrification system, along the flue gas flow direction, the solid waste co-firing boiler flue gas SCR denitrification system is connected to the downstream of the cyclone separator, and the solid waste co-firing boiler flue gas SCR denitrification system is a solid waste co-firing boiler flue gas SCR denitrification system as described in any of the above items.

[0045] The CFB boiler system provided by the utility model has all the technical effects of the solid waste co-firing boiler flue gas SCR denitrification system, and will not be described in detail in this article. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0047] Figure 1 A schematic diagram of the structure of a flue gas SCR denitrification system for solid waste mixed combustion boiler provided in an embodiment of the utility model;

[0048] Figure 2 A schematic diagram of the structure of an interception and purge device provided in one embodiment of the utility model;

[0049] Figure 3 A schematic structural diagram of an interception and purge device provided in another embodiment of the utility model;

[0050] Figure 4 A schematic diagram of the structure of a porous intercepting plate provided in one embodiment of the utility model;

[0051] Figure 5 A schematic diagram of the structure of a porous intercepting plate provided in another embodiment of the utility model;

[0052] Figure 6 A front view of a pulse cleaner provided by an embodiment of the utility model;

[0053] Figure 7 A top view of a pulse cleaner provided by an embodiment of the utility model;

[0054] Figure 8 A schematic diagram of the structure of a rake-type sootblower provided in an embodiment of the utility model;

[0055] Fig. 9 A schematic structural diagram of a sootblower rake pipe provided in an embodiment of the utility model.

[0056] The meanings of the reference numerals in the figures are as follows:

[0057] 101-first heat exchange zone;

[0058] 102-SCR inlet flue;

[0059] 103-SCR reactor;

[0060] 104-SCR outlet flue;

[0061] 105-second heat exchange zone;

[0062] 106-SCR inlet damper valve;

[0063] 107-SCR outlet damper valve;

[0064] 108-Bypass damper valve;

[0065] 109-intercepting purge device; 1091-porous intercepting plate; 10911-vent; 1092-pulse sweeper; 10921-nozzle inlet; 10922-nozzle outlet;

[0066] 110-ash hopper;

[0067] 111- catalyst module;

[0068] 112-rake type sootblowing device; 1121-Roots blower; 1122-sootblowing shut-off valve; 1123-driving device; 1124-sootblowing rake pipe; 1125-anti-blocking fan; 1126-check valve; 1127-manual valve. DETAILED DESCRIPTION

[0069] The core of the utility model is to provide a solid waste mixed combustion boiler flue gas SCR denitrification system to extend the service life of the catalyst module;

[0070] Another core of the utility model is to provide a CFB boiler system having the above-mentioned solid waste co-firing boiler flue gas SCR denitrification system.

[0071] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0072] The SCR denitrification system for flue gas from a solid waste-fired boiler is stable, highly reliable, and has high denitrification efficiency. It is an effective supplement to the front-end denitrification process in a solid waste-fired CFB boiler, and is a favorable guarantee for ensuring that the final emissions of the CFB boiler meet the standards. However, in the prior art, the conventional SCR denitrification design is still used, and the changes in the post-combustion and flue gas composition of the CFB boiler are not taken into account, such as the effect of the increase of alkali metals and heavy metals in the flue dust on the poisoning and deactivation of the catalyst; the effect of solid waste post-combustion on the sintering and failure of the catalyst; the conventional steam soot blowing method and alkaline dust are prone to cause dust agglomeration and blockage of the catalyst; and due to the increase of alkali metals, the dust is highly sticky, the ordinary steam soot blowing effect is poor, and the dust is difficult to remove, etc. These design deficiencies will greatly reduce the stability and reliability of the operation of the SCR denitrification system for flue gas from a solid waste-fired boiler, greatly reduce the life of the catalyst, and cause boiler shutdown due to catalyst blockage.

[0073] The existing flue gas denitrification system of CFB boilers is equipped with a low-nitrogen combustion system, which is used to reduce the NOx concentration from the original end through air classification and other means; it can basically control the NOx concentration at 150mg / Nm 3 At the same time, a SNCR denitrification device is installed at the inlet of the cyclone separator of the CFB boiler, so that the flue gas denitrification system can meet the emission requirements in most scenarios. Only when the boiler is at a low load of 50-70%, the emission may not meet the standard.

[0074] That is, the SCR denitrification system for flue gas from a solid waste-burning boiler downstream of the SNCR denitrification device along the flue gas flow direction is only required in some scenarios; if the flue gas continues to enter the SCR denitrification system for flue gas from a solid waste-burning boiler for further denitrification treatment regardless of whether the flue gas meets the emission requirements, then in most scenarios, the SCR denitrification system for flue gas from a solid waste-burning boiler will significantly affect the activity maintenance of the SCR catalyst when denitrifying the flue gas that meets the standards, shortening the service life of the catalyst module and increasing the denitrification cost.

[0075] Based on this, the utility model embodiment discloses a solid waste mixed combustion boiler flue gas SCR denitrification system, such as Figure 1 As shown, the flue gas SCR denitrification system of the solid waste co-firing boiler includes a heat exchange flue and an SCR reactor 103. The heat exchange flue is located downstream of the SNCR denitrification device along the flue gas flow direction. The heat exchange flue includes a first heat exchange zone 101 and a second heat exchange zone 105. A bypass damper valve 108 is provided in the heat exchange flue. It can be understood by those skilled in the art that the bypass damper valve 108 can control the cutoff and conduction of the first heat exchange zone 101 and the second heat exchange zone 105 by manual or external driving device.

[0076] The bypass damper valve 108 is located between the first heat exchange zone 101 and the second heat exchange zone 105. The first heat exchange zone 101 and the second heat exchange zone 105 are both provided with corresponding heat exchange devices to exchange heat with the flue gas to utilize the heat carried by the flue gas. The temperature of the first heat exchange zone 101 is greater than the temperature of the second heat exchange zone 105. It should be noted that the temperature of the first heat exchange zone 101 is greater than the temperature of the second heat exchange zone 105, which means that along the flow direction of the flue gas, the first heat exchange zone 101 is located upstream of the second heat exchange zone 105, so the temperature of the flue gas in the first heat exchange zone 101 will be greater than the temperature of the flue gas in the second heat exchange zone 105.

[0077] The SCR reactor 103 can protect the reactor body and the SCR inlet flue 102 and the SCR outlet flue 104 connected to the reactor body. The SCR inlet flue 102 is connected to the first heat exchange zone 101, and the SCR outlet flue 104 is connected to the second heat exchange zone 105. The SCR inlet flue 102 can be arranged above the reactor body, and the SCR outlet flue 104 can be arranged below the reactor body, so that the flue gas that needs to be treated by the SCR reactor 103 enters the reactor body from the top of the reactor body through the SCR inlet flue 102 and reacts with the catalyst module 111. In this embodiment, the flow direction of the flue gas in the reactor body is designed to be from top to bottom, which can slow down the flow speed of the flue gas and increase the reaction time with the catalyst module 111. It should be noted that the arrangement positions of the SCR inlet flue 102 and the SCR outlet flue 104 on the reactor body can also be designed according to needs, as long as the flue gas can flow through the catalyst module 111.

[0078] An SCR inlet damper valve 106 is provided in the SCR inlet flue 102, and an SCR outlet damper valve 107 is provided in the SCR outlet flue 104. The SCR inlet damper valve 106 and the SCR outlet damper valve 107 can be controlled to open and close manually or by external device driving to connect or cut off the SCR inlet damper valve 106 and the SCR outlet damper valve 107.

[0079] The SCR denitration system for flue gas of a solid waste co-combustion boiler provided by the utility model, when the flue gas after denitration treatment by the upstream denitration device (such as the SNCR denitration device) cannot meet the emission requirements, the bypass damper valve 108 is closed, and the SCR inlet damper valve 106 and the SCR outlet damper valve 107 are opened. The high-temperature flue gas passes through the first heat exchange zone 101 of the heat exchange flue, and exchanges heat with the heat exchange device in the first heat exchange zone 101, reducing the flue gas temperature to 300°C to 400°C, and then is introduced into the SCR reactor 103 through the SCR inlet flue 102 of the SCR reactor 103. The NOx in the flue gas and the ammonia escaping from the upstream denitration device undergo a denitration reaction under the catalytic action of the catalyst module 111 in the SCR reactor 103, and the NOx is reduced to nitrogen and water. The flue gas after denitration is connected back to the second heat exchange zone 105 of the heat exchange flue through the SCR outlet flue 104 for further heat exchange.

[0080] When the flue gas after denitration treatment by the upstream denitration device can meet the emission requirements, the bypass damper valve 108 is opened, the SCR inlet damper valve 106 and the SCR outlet damper valve 107 are closed, and the SCR reactor 103 is bypassed; the high-temperature flue gas is discharged after heat exchange by the heat exchange devices of the first heat exchange zone 101 and the second heat exchange zone 105 of the heat exchange flue. The utility model uses the SCR reactor 103 for further denitration treatment only when the upstream denitration device cannot meet the emission requirements to ensure that the flue gas emission meets the standard; when the upstream denitration device can meet the emission requirements, the flue gas can be discharged directly after heat exchange through the heat exchange flue without passing through the SCR reactor 103, reducing unnecessary contact between the catalyst module 111 and the flue gas and dust, and extending the catalyst life.

[0081] In a specific embodiment of the present invention, the SCR inlet damper valve 106 and the SCR outlet damper valve 107 are controlled in linkage with the bypass damper valve 108. The linkage control means that one of the bypass damper valve 108 and the damper valve of the SCR reactor 103 is opened and the other is closed. The specific linkage can be realized by a circuit or a controller.

[0082] When the SCR inlet damper valve 106 and the SCR outlet damper valve 107 are opened, the bypass damper valve 108 is closed; when the SCR inlet damper valve 106 and the SCR outlet damper valve 107 are closed, the bypass damper valve 108 is opened. Through linkage control, the switching of the denitration mode can be conveniently realized; for example, the working mode of the SCR denitration system of the flue gas of the solid waste co-combustion boiler is switched according to whether the denitration result of the upstream denitration equipment meets the emission requirements. When the denitration result of the upstream denitration equipment does not meet the emission requirements, the SCR denitration system of the flue gas of the solid waste co-combustion boiler is controlled to enter the working mode, that is, the SCR inlet damper valve 106 and the SCR outlet damper valve 107 are controlled to be opened, and the bypass damper valve 108 is closed; when the denitration result of the upstream denitration equipment meets the emission requirements, the SCR denitration system of the flue gas of the solid waste co-combustion boiler is controlled to enter the bypass mode, that is, the SCR inlet damper valve 106 and the SCR outlet damper valve 107 are controlled to be closed, and the bypass damper valve 108 is opened.

[0083] Whether the denitration result of the upstream denitration equipment meets the emission requirements can be detected by a nitrogen oxide sensor, that is, the nitrogen oxide sensor is used to detect the content of nitrogen oxides in the flue gas in the first heat exchange zone 101. When the content of nitrogen oxides exceeds the preset content (the preset content can be calibrated according to the emission requirements), the solid waste mixed combustion boiler flue gas SCR denitration system is controlled to enter the working mode, that is, the SCR inlet damper valve 106 and the SCR outlet damper valve 107 are opened, and the bypass damper valve 108 is closed. When the content of nitrogen oxides is lower than the preset content, the solid waste mixed combustion boiler flue gas SCR denitration system is controlled to enter the bypass mode, that is, the SCR inlet damper valve 106 and the SCR outlet damper valve 107 are closed, and the bypass damper valve 108 is opened.

[0084] Whether the denitration results of the upstream denitration equipment meet the emission requirements can also be detected by temperature sensors. Those skilled in the art can understand that the operating conditions of the CFB boiler are positively correlated with the denitration efficiency of the SNCR denitration device. When the CFB boiler is under high load conditions (above 50-70% load), the inlet temperature of the cyclone separator is 800℃~950℃, which is the optimal reaction temperature of SNCR. It has been verified that under high load conditions, only low nitrogen combustion + SNCR denitration can achieve NOx emissions <50mg / Nm 3 , to meet the requirements of ultra-low emissions; when the CFB boiler is operating under low load conditions (below 50-70% load), the SNCR efficiency will be greatly reduced due to the reduction in the cyclone separator inlet temperature. It is impossible to meet the requirements of ultra-low emissions only through low-nitrogen combustion + SNCR denitrification.

[0085] It can be seen that the denitrification efficiency of the SNCR denitrification device is directly related to the temperature. The utility model can use a temperature sensor to detect the temperature of the flue gas upstream of the first heat exchange zone 101, for example, the inlet temperature of the cyclone separator can be detected. When the temperature exceeds a preset temperature (the preset temperature can be calibrated according to the ideal reaction temperature of the SNCR denitrification device), the SCR denitrification system of the flue gas from the solid waste combustion boiler is controlled to enter the bypass mode, that is, the SCR inlet damper valve 106 and the SCR outlet damper valve 107 are closed, and the bypass damper valve 108 is opened; when the temperature is lower than the preset temperature, the SCR denitrification system of the flue gas from the solid waste combustion boiler is controlled to enter the working mode, that is, the SCR inlet damper valve 106 and the SCR outlet damper valve 107 are opened, and the bypass damper valve 108 is closed.

[0086] Solid waste is relatively light and can be easily carried away by the flue gas before being completely burned in the furnace of the CFB boiler, resulting in after-combustion. If the after-combustion burns on the surface of the catalyst module 111 of the SCR denitrification system of the flue gas of the solid waste-combustion boiler, the catalyst module 111 will be overheated and sintered and deactivated, causing the catalyst module 111 to fail.

[0087] Based on this, Figure 1-Figure 3 As shown, in this embodiment, an interception and purge device 109 is provided in the SCR inlet flue 102, and the interception and purge device 109 is used to intercept unburned solid waste. The interception and purge device 109 can allow flue gas to pass through, and unburned solid waste with a large volume cannot pass through the interception and purge device 109, and is intercepted upstream of the interception and purge device 109, so that it cannot pass through the interception and purge device 109 and enter the SCR reactor 103. Therefore, it can avoid the problem that the catalyst module 111 is sintered and deactivated due to excessive temperature caused by combustion on the surface of the catalyst module 111, resulting in failure of the catalyst module 111.

[0088] Specifically, the interception and purge device 109 may include a porous interception plate 1091 and a pulse sweeper 1092. The porous interception plate 1091 is arranged in the SCR inlet flue 102, and the projection of the porous interception plate 1091 on the cross section of the SCR inlet flue 102 coincides with the cross section of the SCR inlet flue 102, that is, the porous interception plate 1091 needs to fill the flow area of ​​the SCR inlet flue 102, so that there is no gap between the porous interception plate 1091 and the flue wall of the SCR inlet flue 102, thereby preventing unburned solid waste from entering the SCR reactor 103 through the gap between the porous interception plate 1091 and the flue wall of the SCR inlet flue 102.

[0089] The porous interception plate 1091 can be used Figure 2The arrangement of the V-shaped structure shown, that is, in this embodiment, the porous interception plate 1091 is composed of two interception plate bodies, one end of the two interception plate bodies are connected, and the plate surfaces of the two interception plate bodies are no longer on the same plane, so that the porous interception plate 1091 has a V-shaped structure; such an arrangement can make the effective area of ​​the porous interception plate 1091 larger than the cross-sectional area of ​​the SCR inlet flue 102, thereby improving the filtration efficiency.

[0090] The porous interception plate 1091 can also be used Figure 3 The arrangement of the inclined surface structure shown in the figure, that is, in this embodiment, the porous interception plate 1091 is composed of a piece of interception plate body. It should be noted that, in addition to using one interception plate body in this embodiment and two interception plate bodies in the previous embodiment, the porous interception plate 1091 can also be composed of other numbers of interception plate bodies. In addition, each interception plate body of the porous interception plate 1091 can be an integrated structure, or each interception plate body can be assembled into the porous interception plate 1091 by fasteners or welding.

[0091] like Figure 4 and Figure 5 As shown, the vent holes 10911 of the porous intercepting plate 1091 can be Figure 4 The polygonal holes shown (such as square holes, rectangular holes, parallelogram holes, etc.) can also be Figure 5 The circular hole shown. To ensure effective interception of unburned solid waste, the maximum side length d of the polygonal hole can be designed to be 4mm to 10mm, and the spacing b between two adjacent polygonal holes is 6mm to 14mm. It should be noted that the spacing b between two adjacent polygonal holes refers to the distance between the same positions of two adjacent polygonal holes, not the distance between the closest positions. The diameter R of the circular hole is 4mm to 10mm, and the spacing b between two adjacent circular holes is 6 to 14mm. It should be noted that the spacing b between two adjacent circular holes refers to the distance between the centers of the two adjacent circular holes.

[0092] The pulse cleaner 1092 is used to output pulse gas to purge the surface of the porous intercepting plate 1091. The pulse cleaner 1092 can be arranged at the top of the porous intercepting plate 1091, and the pulse nozzle of the pulse cleaner 1092 is arranged closely to the porous intercepting plate 1091. Its function is to output pulse gas to purge the unburned solid waste intercepted on the surface of the porous intercepting plate 1091, so that it falls off and falls downward, so as to achieve the function of cleaning the porous intercepting plate 1091 and avoid clogging of the porous intercepting plate 1091. It should be noted that the pulse cleaner 1092 can be turned on when the solid waste accumulates to a certain extent, or it can be turned on for a corresponding period of time to clean the solid waste after a period of time.

[0093] In a specific embodiment of the present invention, the SCR inlet flue 102 includes at least a vertical flue section, which extends in the vertical direction. It should be noted that it may also have a certain angle with the vertical direction, and the angle with the vertical direction should not be too large to facilitate the use of gravity.

[0094] The porous intercepting plate 1091 is arranged in the vertical section flue, and the SCR inlet flue 102 is provided with an ash hopper 110 directly below the porous intercepting plate 1091. The angle α between the porous intercepting plate 1091 and the flue wall of the vertical section flue is not greater than 45°. It should be noted that the smaller the angle α between the porous intercepting plate 1091 and the flue wall of the vertical section flue, the larger the angle relative to the horizontal direction, and the less likely the unburned solid waste is to adhere to the porous intercepting plate 1091. The pulse sweeper 1092 outputs pulse gas to purge the unburned solid waste intercepted on the surface of the porous intercepting plate 1091, allowing it to fall off and fall downward into the ash hopper 110, and the fallen solid waste is collected by the ash hopper 110.

[0095] like Figure 6 and Figure 7 As shown, the pulse cleaner 1092 includes a pulse nozzle, one end of the pulse nozzle is a nozzle inlet 10921, and the other end is a nozzle outlet 10922. The nozzle inlet 10921 is used to connect to a compressed air pipeline. The compressed air enters the pulse nozzle through the nozzle inlet 10921 and is ejected from the nozzle outlet 10922. The nozzle outlet 10922 points to the surface of the porous intercepting plate 1091. It should be noted that the nozzle outlet 10922 points to the surface of one side of the porous intercepting plate 1091 close to the ash hopper 110.

[0096] The width of the pulse nozzle gradually increases from the nozzle inlet 10921 to the nozzle outlet 10922. That is, the width of the nozzle outlet 10922 is larger to expand the jet range. The angle between the two side wall panels of the pulse nozzle is generally 30° to 60°.

[0097] The pulse nozzle is divided into an air inlet area and an air outlet area in the direction of air inlet. From the nozzle inlet 10921 to the nozzle outlet 10922, the height of the air outlet area gradually decreases, so that the compressed gas is affected by the gradually decreasing height of the air outlet area, and the flow rate gradually increases. At the same time, due to the gradual decrease in the height of the air outlet area, a narrow gap is formed at the nozzle outlet 10922. The gap height h of the nozzle outlet 10922 is generally 5mm to 15mm. Through the control of the pulse valve of the pulse sweeper 1092, a large amount of compressed air is quickly ejected from the slit-shaped nozzle outlet 10922 in a short time to purge the porous intercepting plate 1091.

[0098] The alkali metals in the flue gas will increase the viscosity of the dust, making the dust more hydrophilic. In addition, the SCR denitrification system for flue gas from solid waste-combustion boilers uses conventional steam soot blowing, and a small amount of water will be sprayed into the catalyst module 111. After contacting the dust, it is easy to agglomerate and become sticky, causing the catalyst module 111 to be blocked and the resistance to increase significantly.

[0099] like Figure 8 As shown, in this embodiment, a catalyst module 111 and a rake sootblower 112 disposed on the upper portion of the catalyst module 111 are disposed in the SCR reactor 103. The rake sootblower 112 includes a sootblowing rake pipe 1124, a driving device 1123 and a Roots blower 1121.

[0100] The rake sootblowing pipe 1124 may include a connected main sootblowing pipe and a plurality of branch sootblowing pipes connected to the main sootblowing pipe to increase the coverage area of ​​the rake sootblowing pipe 1124. The rake sootblowing pipe 1124 is disposed on the upper part of the catalyst module 111 and has an air injection port directed toward the catalyst module 111.

[0101] like Fig. 9 As shown, the aperture m and hole spacing dp of the sootblower pipe 1124 are related to the pitch of the catalyst module. The aperture m is generally 1 mm to 3 mm, and the hole spacing dp is generally 6 mm to 13 mm, which can achieve one-to-one comprehensive blowing with the holes of the catalyst module to ensure the permeability of the channels of the catalyst module.

[0102] The driving device 1123 is used to drive the sootblowing rake pipe 1124 to move in a plane parallel to the catalyst module 111. The present embodiment does not limit the specific structure of the driving device 1123, and it may be a linear motor, a cylinder, a hydraulic cylinder, etc., as long as it can drive the sootblowing rake pipe 1124 to move, so that the sootblowing rake pipe 1124 can move to apply sootblowing air to any position of the catalyst module 111, thereby increasing the sootblowing coverage area.

[0103] The driving device 1123 and the soot blowing rake pipe 1124 constitute the main structure of the rake type soot blowing device 112. The driving device 1123 drives the soot blowing rake pipe 1124 to move on the surface of the catalyst module 111, thereby blowing and cleaning the surface of the catalyst module 111. The driving device 1123 adopts frequency conversion control to adjust the running speed of the soot blowing rake pipe 1124 according to the dust accumulation situation.

[0104] The Roots blower 1121 is connected to the soot blowing rake pipe 1124 through the soot blowing pipeline. That is, the soot blowing medium comes from the low-pressure compressed air with a pressure of 0.8 bar to 1.6 bar and a temperature of 100°C to 150°C generated by the Roots blower 1121. The advantage of using low-pressure compressed air is that there is no condensed water in low-pressure compressed air, and no moisture will be brought in to cause flue gas dust to agglomerate; and because the compressed air pressure is low, the throttling effect is weak at the jet port, the temperature drop is not obvious, and no local condensation will occur, thereby not bringing negative effects.

[0105] Furthermore, a sootblowing shutoff valve 1122 is provided on the sootblowing pipeline, and a corresponding number of sootblowing rake pipes 1124 can be provided according to the number of catalyst modules 111, that is, the sootblowing rake pipes 1124 can be multiple in parallel, and each sootblowing rake pipe 1124 is correspondingly provided with a driving device 1123, and each sootblowing rake pipe 1124 is provided with a separately controlled sootblowing shutoff valve 1122. Each driving device 1123 can act synchronously or independently. Under normal circumstances, each sootblowing rake pipe 1124 can complete the sootblowing action of the corresponding catalyst module 111 in turn. Each sootblowing rake pipe 1124 can share a Roots blower 1121, and the number of corresponding Roots blowers 1121 can be arranged in multiples according to demand.

[0106] When soot blowing is required, the soot blowing shutoff valve 1122 is opened to send low-pressure compressed air into the soot blowing rake pipe 1124. When the soot blowing rake pipe 1124 stops soot blowing, the soot blowing shutoff valve 1122 is closed, and each rake soot blowing device 112 is controlled to perform soot blowing through the soot blowing shutoff valve 1122 and the driving device 1123.

[0107] Further, the rake sootblowing device 112 may also include an anti-blocking fan 1125 and a check valve 1126, and a plurality of anti-blocking fans 1125 may be arranged. The anti-blocking fan 1125 is connected to the sootblowing pipeline between the sootblowing rake pipe 1124 and the sootblowing shut-off valve 1122 through an anti-blocking pipeline. The check valve 1126 is arranged on the anti-blocking pipeline. When the sootblowing shut-off valve 1122 is closed, the check valve 1126 is opened, so that in the direction from the anti-blocking fan 1125 to the sootblowing rake pipe 1124, the check valve 1126 is in a conducting state. When the sootblowing shut-off valve 1122 is opened, the check valve 1126 is closed, so that in the direction from the anti-blocking fan 1125 to the sootblowing rake pipe 1124, the check valve 1126 is in a cut-off state.

[0108] In order to control the on-off of the anti-blocking pipeline, a manual valve 1127 may also be provided on the anti-blocking pipeline, and the manual valve 1127 is provided between the check valve 1126 and the anti-blocking fan 1125 .

[0109] The pressure output by the anti-blocking fan 1125 is lower than the pressure output by the Roots blower 1121. When the soot blowing shut-off valve 1122 is opened, the low-pressure compressed air generated by the Roots blower 1121 enters the soot blowing rake pipe 1124 to blow soot on the surface of the catalyst module 111. The pressures generated by the Roots blower 1121 and the anti-blocking fan 1125 will both act on the valve core of the check valve 1126. Since the pressure output by the anti-blocking fan 1125 is lower than the pressure output by the Roots blower 1121, the valve core of the check valve 1126 moves until the check valve 1126 is closed. Therefore, in the direction from the anti-blocking fan 1125 to the soot blowing rake pipe 1124, the check valve 1126 is also cut off, blocking the anti-blocking wind generated by the anti-blocking fan 1125 from entering the soot blowing rake pipe 1124.

[0110] When the sootblowing shutoff valve 1122 is closed, sootblowing stops. Due to the loss of the pressure generated by the Roots blower 1121, the smoke in the SCR reactor 103 easily blocks the air jet of the sootblowing rake pipe 1124. In this embodiment, after the pressure generated by the Roots blower 1121 is lost, the valve core of the check valve 1126 is moved to open the check valve 1126, and the anti-blocking wind generated by the anti-blocking fan 1125 is passed into the sootblowing rake pipe 1124. When sootblowing is not in progress, it can be ensured that the pressure at the air jet on the sootblowing rake pipe 1124 is greater than the surrounding pressure, thereby preventing the air jet on the sootblowing rake pipe 1124 from being blocked.

[0111] The embodiment of the utility model also discloses a CFB boiler system, which includes a boiler body, a cyclone separator, an SNCR denitrification module and a solid waste mixed combustion boiler flue gas SCR denitrification system. Among them, the cyclone separator is connected to the flue gas outlet of the boiler body, and the SNCR denitrification module is arranged in the flue between the cyclone separator and the boiler body; along the flue gas flow direction, the solid waste mixed combustion boiler flue gas SCR denitrification system is connected to the downstream of the cyclone separator, and the solid waste mixed combustion boiler flue gas SCR denitrification system is the solid waste mixed combustion boiler flue gas SCR denitrification system disclosed in the above embodiment. The CFB boiler system provided by the utility model has the above-mentioned solid waste mixed combustion boiler flue gas SCR denitrification system, so it has all the technical effects of the above-mentioned solid waste mixed combustion boiler flue gas SCR denitrification system, which will not be repeated here.

[0112] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements. The elements defined by the sentence "includes a..." do not exclude the existence of other identical elements in the process, method, commodity or device that includes the elements.

[0113] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0114] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0115] This article uses specific examples to illustrate the principles and implementation methods of the utility model. The above examples are only used to help understand the method and core ideas of the utility model. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the utility model, the utility model can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the utility model.

Claims

1. A solid waste mixed combustion boiler flue gas SCR denitrification system, characterized in that: include: A heat exchange flue, the heat exchange flue comprising a first heat exchange zone (101) and a second heat exchange zone (105); a bypass damper valve (108) is provided in the heat exchange flue, the bypass damper valve (108) is located between the first heat exchange zone (101) and the second heat exchange zone (105); the temperature of the first heat exchange zone (101) is greater than the temperature of the second heat exchange zone (105); An SCR reactor (103), wherein the SCR reactor (103) is connected to the first heat exchange zone (101) via an SCR inlet flue (102), and the SCR reactor (103) is connected to the second heat exchange zone (105) via an SCR outlet flue (104), an SCR inlet damper valve (106) is provided in the SCR inlet flue (102), and an SCR outlet damper valve (107) is provided in the SCR outlet flue (104).

2. The solid waste mixed combustion boiler flue gas SCR denitrification system according to claim 1 is characterized in that: The SCR inlet damper valve (106) and the SCR outlet damper valve (107) are controlled in linkage with the bypass damper valve (108); When the SCR inlet damper valve (106) and the SCR outlet damper valve (107) are opened, the bypass damper valve (108) is closed; when the SCR inlet damper valve (106) and the SCR outlet damper valve (107) are closed, the bypass damper valve (108) is opened.

3. The solid waste mixed combustion boiler flue gas SCR denitrification system according to claim 2 is characterized in that: The system further comprises a nitrogen oxide sensor, wherein the nitrogen oxide sensor is used to detect the nitrogen oxide content in the flue gas in the first heat exchange area (101); when the nitrogen oxide content exceeds a preset content, the SCR inlet damper valve (106) and the SCR outlet damper valve (107) are opened, and the bypass damper valve (108) is closed; when the nitrogen oxide content is lower than a preset content, the SCR inlet damper valve (106) and the SCR outlet damper valve (107) are closed, and the bypass damper valve (108) is opened; or, The system also includes a temperature sensor, which is used to detect the temperature of the flue gas upstream of the first heat exchange zone (101). When the temperature exceeds a preset temperature, the SCR inlet damper valve (106) and the SCR outlet damper valve (107) are closed, and the bypass damper valve (108) is opened. When the temperature is lower than a preset temperature, the SCR inlet damper valve (106) and the SCR outlet damper valve (107) are opened, and the bypass damper valve (108) is closed.

4. The solid waste mixed combustion boiler flue gas SCR denitrification system according to claim 1 is characterized in that: An interception and purge device (109) is provided in the SCR inlet flue (102), and the interception and purge device (109) is used to intercept unburned solid waste.

5. The solid waste mixed combustion boiler flue gas SCR denitrification system according to claim 4 is characterized in that: The interception and purge device (109) comprises a porous interception plate (1091) and a pulse sweeper (1092), wherein the porous interception plate (1091) is arranged in the SCR inlet flue (102), and a projection of the porous interception plate (1091) on a cross section of the SCR inlet flue (102) coincides with the cross section of the SCR inlet flue (102); The pulse sweeper (1092) is used to output pulse gas to purge the surface of the porous intercepting plate (1091).

6. The solid waste mixed combustion boiler flue gas SCR denitrification system according to claim 5 is characterized in that: The SCR inlet flue (102) comprises at least a vertical flue section, the porous intercepting plate (1091) is arranged in the vertical flue section, and the SCR inlet flue (102) is provided with an ash hopper (110) directly below the porous intercepting plate (1091).

7. The solid waste mixed combustion boiler flue gas SCR denitrification system according to claim 6 is characterized in that: The angle α between the porous intercepting plate (1091) and the flue wall of the vertical flue section is not greater than 45°.

8. The solid waste mixed combustion boiler flue gas SCR denitrification system according to claim 6, characterized in that: The pulse cleaner (1092) comprises a pulse nozzle, one end of the pulse nozzle is a nozzle inlet (10921), and the other end is a nozzle outlet (10922), and the width of the pulse nozzle gradually increases in the direction from the nozzle inlet (10921) to the nozzle outlet (10922); The pulse nozzle is divided into an air intake zone and an air outlet zone along the air intake direction, and the height of the air outlet zone gradually decreases from the nozzle inlet (10921) to the nozzle outlet (10922).

9. The solid waste mixed combustion boiler flue gas SCR denitrification system according to claim 5, characterized in that: The ventilation holes (10911) of the porous intercepting plate (1091) are polygonal holes or circular holes; The maximum side length d of the polygonal hole is 4 to 10 mm, and the distance b between two adjacent polygonal holes is 6 to 14 mm; The diameter R of the circular hole is 4 to 10 mm, and the distance b between two adjacent circular holes is 6 to 14 mm.

10. The solid waste mixed combustion boiler flue gas SCR denitrification system according to any one of claims 1 to 9, characterized in that: The SCR reactor (103) is provided with a catalyst module (111) and a rake-type sootblower (112) arranged on the top of the catalyst module (111).

11. The solid waste mixed combustion boiler flue gas SCR denitrification system according to claim 10, characterized in that: The rake-type sootblowing device (112) comprises: A sootblowing rake pipe (1124) is arranged on the upper part of the catalyst module (111), and the sootblowing rake pipe (1124) has an air injection port pointing to the catalyst module (111); A driving device (1123) for driving the sootblowing rake pipe (1124) to move in a plane parallel to the catalyst module (111); The Roots blower (1121) is connected to the soot blowing rake pipe (1124) through a soot blowing pipeline.

12. The solid waste mixed combustion boiler flue gas SCR denitrification system according to claim 11, characterized in that: A sootblowing shut-off valve (1122) is provided on the sootblowing pipeline.

13. The solid waste mixed combustion boiler flue gas SCR denitrification system according to claim 12, characterized in that: The sootblowing rake pipes (1124) are multiple and connected in parallel, and each of the sootblowing rake pipes (1124) is correspondingly provided with the driving device (1123), and each of the sootblowing rake pipes (1124) is provided with a sootblowing shut-off valve (1122) that is individually controlled.

14. The solid waste mixed combustion boiler flue gas SCR denitrification system according to claim 12, characterized in that: The rake-type sootblowing device (112) further includes an anti-blocking fan (1125), connected to the soot blowing pipeline between the soot blowing rake pipe (1124) and the soot blowing shut-off valve (1122) through an anti-blocking pipeline; The check valve (1126) is arranged on the anti-blocking pipeline. When the sootblowing shut-off valve (1122) is closed, the check valve (1126) is opened, so that in the direction from the anti-blocking fan (1125) to the sootblowing rake pipe (1124), the check valve (1126) is in a conducting state. When the sootblowing shut-off valve (1122) is opened, the check valve (1126) is closed, so that in the direction from the anti-blocking fan (1125) to the sootblowing rake pipe (1124), the check valve (1126) is in a blocking state.

15. The solid waste mixed combustion boiler flue gas SCR denitrification system according to claim 14, characterized in that: A manual valve (1127) is also provided on the anti-blocking pipeline, and the manual valve (1127) is provided between the check valve (1126) and the anti-blocking fan (1125).

16. A CFB boiler system, characterized in that: include: Boiler body; a cyclone separator, connected to the flue gas outlet of the boiler body; An SNCR denitration module is arranged in the flue between the cyclone separator and the boiler body; A solid waste co-firing boiler flue gas SCR denitrification system, along the flue gas flow direction, the solid waste co-firing boiler flue gas SCR denitrification system is connected to the downstream of the cyclone separator, and the solid waste co-firing boiler flue gas SCR denitrification system is the solid waste co-firing boiler flue gas SCR denitrification system as described in any one of claims 1-15.

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