Tubular rotary pyrolysis device and denitration system

Abstract

The invention discloses a tubular rotary pyrolysis device and a denitration system. The tubular rotary pyrolysis device comprises a barrel, an exhaust pipeline, a high-temperature heat source input pipeline and a plurality of heat transfer pipes, a material inlet header is arranged at one end of the barrel, a material outlet header is arranged at the other end of the barrel, a material inlet is formed in the material inlet header, and an exhaust pipeline penetrates through the material inlet header to be communicated with the center of the end face of the barrel. The high-temperature heat source input pipeline penetrates through the material outlet header, is inserted into the barrel and then is communicated with the barrel center pipe in the barrel, a plurality of through holes are formed in the side wall of the barrel center pipe, one end of each heat transfer pipe is inserted into the material inlet header, and the other end of each heat transfer pipe penetrates through the barrel in the axial direction and then is inserted into the material outlet header. And a pyrolysis ammonia gas outlet and a material slag discharge port are formed in the material outlet header. The device can remarkably improve the heat exchange efficiency and the ammonia production efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental protection and relates to a tubular rotary pyrolysis device and a denitration system. Background Art

[0002] With increasingly stringent environmental protection requirements, the efficiency and safety of thermal power plant denitrification systems are facing new challenges. At present, the commonly used reducing agents in thermal power plant denitrification systems include liquid ammonia, ammonia water and urea. Liquid ammonia, as a Class B dangerous goods stipulated by the state, has major safety hazards; although ammonia water is relatively safe, it has high transportation costs and requires large storage equipment; the investment and operating costs of the urea system are high, and the system consumes a lot of energy.

[0003] Ammonium bicarbonate has attracted widespread attention as a safe and low-cost alternative. It is stored in solid particles at room temperature and pressure, and there is no safety problem. More importantly, ammonium bicarbonate can begin to decompose and produce ammonia at around 100°C, and the pyrolysis rate increases rapidly with increasing temperature. However, the existing ammonium bicarbonate pyrolysis ammonia production device has problems such as low heat exchange efficiency, high energy consumption, and insufficient reaction. Therefore, it is urgent to develop an efficient and energy-saving ammonium bicarbonate pyrolysis ammonia production device. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a tubular rotary pyrolysis device and a denitrification system, which can significantly improve the heat exchange efficiency and ammonia production efficiency.

[0005] To achieve the above object, the present invention discloses a tubular rotary pyrolysis device comprising a cylinder, an exhaust pipe, a high-temperature heat source input pipe and a plurality of heat transfer pipes;

[0006] A material inlet manifold is provided at one end of the cylinder, and a material outlet manifold is provided at the other end of the cylinder, wherein a material inlet is provided on the material inlet manifold, an exhaust pipe passes through the material inlet manifold and is connected with the center position of the end face of the cylinder, a high-temperature heat source input pipe passes through the material outlet manifold and is inserted into the cylinder and then is connected with the cylinder center tube in the cylinder, a plurality of through holes are provided on the side wall of the cylinder center tube, one end of each heat transfer tube is inserted into the material inlet manifold, and the other end of each heat transfer tube passes through the cylinder axially and then is inserted into the material outlet manifold, and a pyrolysis ammonia outlet and a material slag discharge port are provided on the material outlet manifold.

[0007] Furthermore, the cylinder is installed on the supporting device at an angle.

[0008] Furthermore, the heat transfer tubes are arranged in parallel, and spiral tracks are provided inside the heat transfer tubes.

[0009] Furthermore, the material inlet is arranged at the high end of the material inlet header, and a spiral feeding mechanism is used for feeding. An anti-blocking device and a uniform distributor are arranged in the material inlet header.

[0010] Furthermore, a regulating valve is provided on the high-temperature heat source input pipeline.

[0011] Furthermore, a dust removal device and a condenser are provided at the pyrolysis ammonia outlet.

[0012] Furthermore, it also includes a driving device, which is connected to the cylinder and is used to drive the cylinder to rotate.

[0013] Furthermore, it also includes a pressure gauge, which is arranged in the cylinder.

[0014] Furthermore, it also includes a control system, which is connected to the control end of the driving device, the control end of the regulating valve, the output end of the pressure gauge, and the control end of the spiral feeding mechanism.

[0015] The invention discloses a denitration system, comprising a tubular rotary pyrolysis device.

[0016] The present invention has the following beneficial effects:

[0017] During the specific operation of the tubular rotary pyrolysis device and denitrification system described in the present invention, the high-temperature heat source input pipeline passes through the material outlet header and is inserted into the cylinder body and then communicated with the cylinder center tube in the cylinder body. A plurality of through holes are provided on the side wall of the cylinder center tube. During the pyrolysis process, the high-temperature heat source will fill the cylinder body and exchange heat with the material in the heat transfer tube through the heat transfer tube to improve the heat exchange efficiency and ammonia production efficiency, and the practicability is extremely strong.

[0018] Furthermore, a spiral track is provided in the heat transfer tube, and the spiral angle and spacing are optimized to stir the ammonium bicarbonate particles and promote their movement, thereby improving the uniformity of material movement and the heat transfer efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 It is a structural diagram of the present invention;

[0021] Figure 2 This is the location diagram of the high temperature heat source inlet;

[0022] Figure 3 is the functional diagram of the control system;

[0023] Figure 4 This is an application scenario diagram of the present invention.

[0024] Among them, 1 is the material inlet, 2 is the exhaust pipe, 3 is the cylinder, 4 is the pyrolysis ammonia outlet, 5 is the high-temperature heat source input pipe, and 6 is the material slag discharge port. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0027] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0028] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0029] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0030] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0033] Embodiment 1

[0034] refer to Figure 1 and Figure 2 The tubular rotary pyrolysis device of the present invention comprises a material inlet 1, an exhaust pipe 2, a cylinder 3, a pyrolysis ammonia outlet 4, a high-temperature heat source input pipe 5 and a material slag discharge port 6; a cylinder center pipe and a plurality of heat transfer pipes are arranged in the cylinder 3, wherein a material inlet header is arranged at one end of the cylinder 3, and a material outlet header is arranged at the other end of the cylinder 3, wherein a material inlet 1 is arranged on the material inlet header, the exhaust pipe 2 passes through the material inlet header and is connected with the center position of the end face of the cylinder 3, the high-temperature heat source input pipe 5 passes through the material outlet header and is inserted into the cylinder 3 and is connected with the cylinder center pipe in the cylinder 3, a plurality of through holes are arranged on the side wall of the cylinder center pipe, one end of each heat transfer pipe is inserted into the material inlet header, and the other end of each heat transfer pipe passes through the cylinder 3 along the axial direction and is inserted into the material outlet header, and a pyrolysis ammonia outlet 4 and a material slag discharge port 6 are arranged on the material outlet header.

[0035] In this embodiment, the length L of the cylinder 3 is 8m, the diameter D is 2m, and the material selected is 316L corrosion-resistant stainless steel, which has excellent corrosion resistance and high temperature strength. The cylinder 3 is tiltedly installed on the supporting device, and the tilt angle adjustment range is 5° to 15° to meet the flow requirements of ammonium bicarbonate material.

[0036] In this embodiment, the heat transfer tubes are arranged in parallel, the number is 20 to 50, the specification is φ108mm×4mm, the tube length is 5000mm, and the tube spacing is 130mm. A spiral track is provided in the heat transfer tube, and the spiral angle and spacing are optimized to stir the ammonium bicarbonate particles and promote their movement to improve the heat transfer efficiency. Specifically, the pitch of the spiral track is 200mm, and the spiral angle is 15°, which improves the uniformity of material movement and heat transfer efficiency.

[0037] In this embodiment, the material inlet 1 is arranged at the high end of the material inlet manifold, and a spiral feeding mechanism is adopted to adjust the feeding rate according to demand. An anti-blocking device and a uniform distributor are provided in the material inlet manifold to ensure that the ammonium bicarbonate particles enter each heat transfer tube evenly.

[0038] The high-temperature heat source input pipe 5 is arranged at the bottom end of the cylinder 3, and is used to introduce high-temperature flue gas or steam. The heat source enters through the central tube of the cylinder, and the specification of the central tube of the cylinder is φ325mm. There are multiple rows of through holes on the wall, and the aperture of the through holes is 5-10mm, and the spacing is 15-50mm. The number of openings near the material inlet is relatively dense, ensuring that the heat source is evenly distributed outside the heat transfer tube. The high-temperature heat source input pipe 5 is provided with a regulating valve, and the flow rate of the heat source can be adjusted according to demand.

[0039] The pyrolysis ammonia outlet 4 is located at the top of the material outlet header, and is used to discharge the mixed gas of NH3, H2O and CO2 generated by pyrolysis. The pyrolysis ammonia outlet 4 is provided with a dust removal device and a condenser, which are used to remove particulate matter and excess moisture in the gas.

[0040] The exhaust pipe 2 is arranged at the central axis of the cylinder 3, and the flow channel is annular. A rotary sealing interface is arranged at the connection position between the exhaust pipe 2 and the cylinder 3, which is used to discharge the flue gas or steam that has completed the heat exchange. The condensed steam is discharged through the drain pipe on the same side as the heat source inlet. The discharged low-temperature flue gas or steam can be further used to preheat the feed; or the discharged low-temperature flue gas directly enters the dust collector, and the discharged low-temperature steam enters the power plant heat recovery system.

[0041] In this embodiment, a driving device is also included, which is connected to the cylinder 3 and is used to drive the cylinder 3 to rotate. The driving device uses a variable frequency speed regulating motor and can achieve a rotation speed adjustment of 0.5 to 5 rpm. The driving device also includes components such as a reducer, a coupling, and a support bearing to ensure smooth and reliable operation.

[0042] In this embodiment, reference Figure 3, also includes a control system, the control system is connected to the control end of the drive device, the control end of the regulating valve, the output end of the pressure gauge, and the control end of the spiral feeding mechanism. The pressure gauge is arranged in the cylinder 3, and the drive device, the regulating valve and the spiral feeding mechanism are controlled by the control system. The control system is used to realize the following functions: a) Temperature control, by adjusting the heat source flow and the rotation speed of the cylinder 3, the reaction temperature is accurately controlled within the range of 120 to 150°C. b) Pressure monitoring, real-time monitoring of the internal pressure of the cylinder 3 to prevent accidental pressure increase. c) Speed ​​regulation, automatically adjusting the rotation speed of the cylinder 3 according to the material characteristics and production capacity requirements. d) Material flow control, by adjusting the feed rate, ensure the best material filling rate (15%-25%). e) Safety protection device, set multiple alarms and interlocking protection mechanisms to ensure the safe operation of the device.

[0043] The working principle of the present invention is:

[0044] Ammonium bicarbonate particles (particle size 1-3mm) enter the heat transfer tube and slowly move downward under the guidance of the spiral track. At the same time, the high-temperature heat source (flue gas 280℃ or steam 180℃) enters from the lower end of the cylinder 3 and conducts convection heat exchange outside the heat transfer tube. As the cylinder 3 rotates, the ammonium bicarbonate particles in the heat transfer tube are constantly turned over, which enhances the heat transfer effect. Ammonium bicarbonate is pyrolyzed at 120-150℃, and the reaction equation is:

[0045] NH4HCO3→NH3+H2O+CO2

[0046] The generated ammonia, water vapor and carbon dioxide mixture is discharged from the pyrolysis ammonia outlet 4, and after dust removal and condensation treatment, it is sent to the boiler denitration system for use. The entire pyrolysis process is carried out under normal pressure, and the reaction temperature is accurately adjusted by controlling the heat source parameters and the rotation speed of the cylinder 3 to ensure that the conversion rate of ammonium bicarbonate reaches more than 95%.

[0047] Embodiment 2

[0048] The present invention is applicable to the denitration system of a 660MW thermal power unit, using 280℃ flue gas as the main heat source. Taking a 660MW unit as an example, the single-furnace ammonia production system is designed to have an ammonia output of 315kg / h, and the required processing capacity of raw material ammonium bicarbonate is 1464kg / h. To ensure complete reaction, the residence time of ammonium bicarbonate solid in the kiln reactor is 20min. Considering the extraction of 280℃ flue gas from the SCR outlet and heat exchange to 120℃, a 15t / h flue gas heating tubular rotary device is required to heat the flue gas to 150℃.

[0049] The length of the cylinder 3 is 8m, the diameter is 2m, and the inclination angle is 10°; taking the 660MW unit as an example, the thermal decomposition of ammonium bicarbonate requires external heating power of about 900kW.

[0050] The selected flue gas heating solution is: 40 built-in heat transfer tubes with dimensions of φ108mm×4mm, tube length of 7000mm and tube spacing of 130mm.

[0051] The raw materials are dried and crushed for pretreatment. The particle size of ammonium bicarbonate material is crushed to 1mm. The feed is evenly fed into the heat transfer tube through a double-screw feeding mechanism, and the filling rate is controlled at 15%. The pyrolysis reaction of ammonium bicarbonate is carried out at 120-150℃ and the speed is 1.0rpm. After the product is condensed, ammonia with a purity of 99.9% is obtained. The heated flue gas enters the boiler dust collector, and the heated steam enters the heat recovery system.

[0052] Economic Benefit Analysis

[0053] Energy consumption is 0.3kWh / kg NH3;

[0054] The conversion rate of ammonium bicarbonate is over 99%;

[0055] The equipment investment saves about 40% compared with the urea hydrolysis system; the annual operating cost is reduced by about 20% compared with the urea hydrolysis system.

[0056] The floor area is roughly estimated to be only 1 / 2 of the floor area of ​​the urea hydrolysis area; the investment recovery period is significantly shortened.

[0057] Embodiment 3

[0058] This embodiment is applicable to the denitration system of a 1000MW thermal power unit, using 280°C flue gas as the main heat source. Taking a 1000MW unit as an example, the single-furnace ammonia production system is designed to have an ammonia output of 375kg / h, and the required processing capacity of raw material ammonium bicarbonate is 1880kg / h. To ensure complete reaction, the residence time of ammonium bicarbonate solid in the kiln reactor is 20min. Considering the extraction of 280°C flue gas from the SCR outlet and heat exchange to 120°C, a 20t / h flue gas heating tubular rotary device is required to be heated to 150°C.

[0059] The size of the cylinder 3 is the same as that of the first embodiment. Taking a 1000MW unit as an example, the thermal decomposition of ammonium bicarbonate requires external heating power of about 1200kW.

[0060] The selected flue gas heating solution is: 50 heat transfer tubes with dimensions of φ108mm×4mm, tube length of 7500mm and tube spacing of 130mm.

[0061] Embodiment 4

[0062] refer to Figure 4The denitration system of the present invention includes a tubular rotary pyrolysis device. The tubular rotary pyrolysis device includes a cylinder 3, an exhaust pipe 2, a high-temperature heat source input pipe 5 and a plurality of heat transfer pipes; a material inlet header is provided at one end of the cylinder 3, and a material outlet header is provided at the other end of the cylinder 3, wherein a material inlet 1 is provided on the material inlet header, the exhaust pipe 2 passes through the material inlet header and is connected to the center position of the end face of the cylinder 3, the high-temperature heat source input pipe 5 passes through the material outlet header and is inserted into the cylinder 3 and is connected to the cylinder center pipe in the cylinder 3, a plurality of through holes are provided on the side wall of the cylinder center pipe, one end of each heat transfer pipe is inserted into the material inlet header, and the other end of each heat transfer pipe passes through the cylinder 3 along the axial direction and is inserted into the material outlet header, and a pyrolysis ammonia outlet 4 and a material slag discharge port 6 are provided on the material outlet header.

[0063] The barrel 3 is installed on the supporting device at an angle; the heat transfer tubes are arranged in parallel, and spiral tracks are provided in the heat transfer tubes; the material inlet 1 is arranged at the high end of the material inlet header, and a spiral feeding mechanism is used for feeding, and an anti-blocking device and a uniform distributor are provided in the material inlet header; a regulating valve is provided on the high-temperature heat source input pipeline 5; a dust removal device and a condenser are provided at the pyrolysis ammonia outlet 4; a driving device is also included, which is connected to the barrel 3 and is used to drive the barrel 3 to rotate; a pressure gauge is also included, which is arranged in the barrel 3; a control system is also included, which is connected to the control end of the driving device, the control end of the regulating valve, the output end of the pressure gauge, and the control end of the spiral feeding mechanism.

[0064] It should be noted that the present invention has the following characteristics:

[0065] 1. High heat exchange efficiency: The design of "particle flow inside the tube and heating by heat source outside the tube" significantly improves the heat exchange efficiency, which is more than 50% higher than that of traditional external heating kilns.

[0066] 2. Low energy consumption: It can make full use of the flue gas or steam waste heat of thermal power plants. Compared with the urea hydrolysis system, the energy consumption is reduced by more than 40%.

[0067] 3. High ammonia production efficiency: Through optimized design and precise control, the conversion rate of ammonium bicarbonate pyrolysis to ammonia can reach more than 95%, which is 10 to 15 percentage points higher than the traditional method.

[0068] 4. The pyrolysis device has a compact structure: compared with the traditional urea hydrolysis system, the floor space is reduced by more than 50%, which is suitable for renovation and installation in limited space.

[0069] 5. Flexible operation: The rotation speed, heat source parameters and feed rate can be adjusted according to needs to adapt to different working conditions and production capacity requirements.

[0070] 6. High safety: It completely avoids the use and storage of dangerous goods such as liquid ammonia, greatly improving the safety of the system.

[0071] 7. Significant environmental benefits: low-grade heat sources from power plants are used as much as possible, reducing additional energy consumption, and further recycling the CO2 produced by pyrolysis to achieve near-zero emissions.

[0072] 8. Excellent economic benefits: low raw material cost, the price of ammonium bicarbonate is about half of urea; small equipment investment and low operating cost.

[0073] 9. High degree of intelligence: The DCS system realizes full process automation control, reduces manual intervention, and improves operational stability and efficiency.

[0074] 10. Strong adaptability: It can flexibly adjust the waste heat utilization source, device specifications and production capacity according to the needs of thermal power units of different sizes, and has broad application prospects.

[0075] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0076] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0077] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A tubular rotary pyrolysis device, characterized in that: It comprises a cylinder (3), an exhaust pipe (2), a high-temperature heat source input pipe (5) and a plurality of heat transfer pipes; A material inlet manifold is provided at one end of the cylinder (3), and a material outlet manifold is provided at the other end of the cylinder (3), wherein a material inlet (1) is provided on the material inlet manifold, an exhaust pipe (2) passes through the material inlet manifold and is connected to the center position of the end face of the cylinder (3), a high-temperature heat source input pipe (5) passes through the material outlet manifold and is inserted into the cylinder (3) and is connected to the cylinder center tube in the cylinder (3), a plurality of through holes are provided on the side wall of the cylinder center tube, one end of each heat transfer tube is inserted into the material inlet manifold, and the other end of each heat transfer tube passes through the cylinder (3) along the axial direction and is inserted into the material outlet manifold, and a pyrolysis ammonia outlet (4) and a material slag discharge port (6) are provided on the material outlet manifold.

2. The tubular rotary pyrolysis device according to claim 1, characterized in that: The cylinder (3) is installed on the supporting device in an inclined manner.

3. The tubular rotary pyrolysis device according to claim 1, characterized in that: The heat transfer tubes are arranged in parallel, and spiral tracks are arranged inside the heat transfer tubes.

4. The tubular rotary pyrolysis device according to claim 1, characterized in that: The material inlet (1) is arranged at the high end of the material inlet header, and a spiral feeding mechanism is used for feeding. An anti-blocking device and a uniform distributor are arranged in the material inlet header.

5. The tubular rotary pyrolysis device according to claim 4, characterized in that: A regulating valve is provided on the high-temperature heat source input pipeline (5).

6. The tubular rotary pyrolysis device according to claim 1, characterized in that: A dust removal device and a condenser are provided at the pyrolysis ammonia outlet (4).

7. The tubular rotary pyrolysis device according to claim 5, characterized in that: It also comprises a driving device, which is connected to the cylinder (3) and is used to drive the cylinder (3) to rotate.

8. The tubular rotary pyrolysis device according to claim 7, characterized in that: It also includes a pressure gauge, which is arranged in the cylinder (3).

9. The tubular rotary pyrolysis device according to claim 8, characterized in that: It also includes a control system, which is connected to the control end of the driving device, the control end of the regulating valve, the output end of the pressure gauge, and the control end of the spiral feeding mechanism.

10. A denitration system, characterized in that: It comprises the tubular rotary pyrolysis device as described in any one of claims 1 to 9.

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