Modularized heat exchanger assembly of waste gas RTO incinerator of carbon fiber production line

Abstract

The invention relates to the technical field, in particular to a carbon fiber production line waste gas RTO incinerator modularized heat exchanger assembly which comprises four heat exchanger modules, the heat exchanger modules are connected in parallel, each heat exchanger module comprises a body, a waste gas inlet pipe is installed on one side of each body, and a waste gas exhaust pipe is installed on the other side of each body. A first control valve is installed on the waste gas inlet pipe, a second control valve is installed on the waste gas discharge pipe, a detection assembly used for detecting the blockage condition of the body is further installed on the body, and an ash removal assembly is installed on the side, facing the waste gas discharge pipe, of the body. The running mode that three sets run and one set is standby is adopted, the RTO system can automatically clean the heat exchanger on line without shutdown, long-term normal running of the system is guaranteed, and the production efficiency is improved; the ash removal assembly is provided with a purging cleaning system and a flushing cleaning system, and the cleaning effect on the heat exchanger is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of heat exchanger technology, and more particularly to a modular heat exchanger assembly for a carbon fiber production line exhaust gas RTO incinerator. Background Technology

[0002] The current RTO process for treating waste gas containing tar and hydrogen cyanide (HCN) from carbon fiber oxidation furnaces involves high-temperature decomposition of HCN at 900-1000℃ using RTO equipment. The exhaust gas temperature from the RTO is 200-300℃, requiring a high-temperature gas-steam heat exchanger to recover heat energy and reduce the overall system energy consumption. However, because the waste gas contains a large amount of tar and organosilicon, the high-temperature decomposition produces a large amount of silica powder, which can clog the current plate or shell-and-tube heat exchangers. This necessitates periodic (usually 1-3 months) shutdowns for RTO equipment maintenance. The 48-hour (2-day) downtime for heat exchanger cleaning causes a drop in the carbon fiber oxidation furnace temperature, requiring readjustment of production line parameters and other preparatory measures for reheating. Furthermore, the 1-2 month shutdowns for cleaning also impact the annual output of carbon fiber companies, thus increasing operating costs. Summary of the Invention

[0003] In view of this, the purpose of this invention is to propose a modular heat exchanger assembly for a carbon fiber production line exhaust gas RTO incinerator, so as to solve the technical problem of long downtime maintenance time of existing heat exchangers.

[0004] Based on the above objectives, the technical solution provided by the present invention is: a modular heat exchanger assembly for a carbon fiber production line exhaust gas RTO incinerator, comprising four sets of heat exchanger modules connected in parallel with each other. Each heat exchanger module includes a body, an exhaust gas inlet pipe installed on one side of the body, an exhaust gas outlet pipe installed on the other side of the body, a first control valve installed on the exhaust gas inlet pipe, a second control valve installed on the exhaust gas outlet pipe, a detection component for detecting blockage of the body, and a dust removal component installed on the side of the body facing the exhaust gas outlet pipe. Among them, the four heat exchanger modules adopt an operation mode of three groups in operation and one group in standby. When the detection component on one group of heat exchanger modules detects that the blockage reaches the threshold, the heat exchanger module in that group stops operating and the standby heat exchanger module is put into operation. The cleaning component on the stopped heat exchanger module performs cleaning work. After the cleaning is completed, the heat exchanger module in that group switches to standby status.

[0005] Optionally, the main body includes a shell, in which a plurality of heat exchange tubes are vertically installed. An air inlet is provided at the upper part of the shell, and the exhaust gas inlet pipe is connected to the air inlet. An air outlet is provided at the lower part of the shell, and the air outlet is connected to the exhaust gas outlet pipe. An ash discharge port is provided at the lower end of the shell, and the ash removal assembly is installed inside the heat exchange tubes.

[0006] Specifically, the dust removal assembly includes an air inlet manifold connected to an external power source. The air outlet of the air inlet manifold is provided with a number of purge pipes. The number of purge pipes is the same as the number of heat exchange tubes, and they are inserted vertically into the heat exchange tubes. A number of purge nozzles are installed on the purge pipes. A third control valve is installed on the air inlet manifold. The air inlet manifold continuously supplies compressed air to the purge pipes to keep the purge pipes under positive pressure.

[0007] Optionally, the purge pipe is also equipped with an atomizing nozzle, which is connected to an external high-pressure water source.

[0008] Optionally, the heat exchange tube is a stainless steel tube with a diameter ≥ DN100mm.

[0009] Optionally, the detection component includes a pressure sensor installed on the exhaust gas inlet pipe and the exhaust gas outlet pipe to detect the pressure difference between the exhaust gas inlet pipe and the exhaust gas outlet pipe.

[0010] Optionally, it also includes control components, all of which are electrically connected to the first control valve, the second control valve, the detection component, and the dust removal component.

[0011] The beneficial effects of this invention are as follows: By setting up four sets of parallel heat exchanger modules and adopting an operating mode of three sets in operation and one set on standby, this invention can realize the automatic online cleaning of heat exchangers in the RTO system without shutting down, ensuring the long-term normal operation of the system and improving production efficiency; the dust removal component has two cleaning systems, namely blowing and rinsing, which ensures the cleaning effect on the heat exchangers. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the modular heat exchanger assembly for the carbon fiber production line exhaust gas RTO incinerator of the present invention. Figure 2 This is a schematic diagram of the heat exchanger module of the present invention; Figure 3 This is a schematic diagram showing the positions of the heat exchange tube and the purge tube of the present invention; Figure 4 This is a schematic diagram showing the position of the purge tube inside the heat exchange tube according to the present invention.

[0014] The components are as follows: 1. Heat exchanger module; 11. Module A; 12. Module B; 13. Module C; 14. Module D; 15. Heat exchange tube; 16. Air inlet; 17. Air outlet; 18. Ash discharge port; 2. Waste gas inlet pipe; 3. Waste gas outlet pipe; 4. First control valve; 5. Second control valve; 6. Detection component; 7. Ash removal component; 71. Main air inlet pipe; 72. Purge pipe; 73. Purge nozzle; 74. Third control valve. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this specification are for illustrative purposes only and do not represent the only possible implementation.

[0017] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items. Example 1

[0018] A modular heat exchanger assembly for a carbon fiber production line exhaust gas RTO incinerator includes four heat exchanger modules 1 (hereinafter referred to as module A 11, module B 12, module C 13 and module D 14). Modules A 11, B 12, C 13 and D 14 are connected in parallel. The four heat exchanger modules 1 adopt an operating mode of three modules in operation and one module on standby. Each heat exchanger module 1 includes a body. An exhaust gas inlet pipe 2 is installed on one side of the body, and an exhaust gas outlet pipe 3 is installed on the other side of the body. A first control valve 4 is installed on the exhaust gas inlet pipe 2, and a second control valve 5 is installed on the exhaust gas outlet pipe 3. A detection component 6 for detecting blockage is also installed on the body. A dust removal component 7 is installed on the side of the body facing the exhaust gas outlet pipe 3.

[0019] The gas requiring heat exchange is divided into four branch pipes from a main pipe, each connected to a heat exchanger module 1. During operation, the exhaust gas passes through modules A (11), B (12), C (13), and D (14), while module D is on standby. After a period of operation, module A (11) is cleaned and put into standby mode, while modules B (12), C (13), and D (14) operate, and so on, achieving continuous online cleaning of the heat exchangers without shutting down the system. Furthermore, subsequent replacement or maintenance is much more convenient. Previously, the heat exchanger was a single unit; if heat exchange tube 15 was damaged, the entire heat exchanger needed to be replaced. Now, any small module can be replaced at a lower cost. Previously, heat exchange tube 15, which could not be automatically cleaned, would become clogged, leading to increased pressure and the possibility of it being flattened by the high-pressure centrifugal fan downstream. By adding an automatic cleaning system, the lifespan of heat exchange tube 15 is significantly increased.

[0020] The main body includes a shell, inside which several heat exchange tubes 15 are vertically installed. The heat exchange tubes 15 are stainless steel tubes with a diameter ≥ DN100mm. Using large-diameter heat exchange tubes 15 can delay the clogging time of the heat exchanger. The upper part of the shell is provided with an air inlet 16, and the exhaust gas inlet pipe 2 is connected to the air inlet 16. The lower part of the shell is provided with an air outlet 17, which is connected to the exhaust gas outlet pipe 3. The lower end of the shell is provided with an ash discharge port 18, and the ash cleaning assembly 7 is installed inside the heat exchange tubes 15.

[0021] Specifically, the dust removal assembly 7 includes an air inlet main pipe 71, which is connected to an external power source. The air outlet of the air inlet main pipe 71 is provided with several purge pipes 72. The purge pipes 72 are DN25mm round pipes. The number of purge pipes 72 is the same as the number of heat exchange tubes 15, and they are inserted vertically into the heat exchange tubes 15. Several purge nozzles 73 are installed on the purge pipes 72. A third control valve 74 is installed on the air inlet main pipe 71. The air inlet main pipe 71 continuously supplies compressed air to the purge pipes 72 to keep the purge pipes 72 in a slightly positive pressure state, so as to prevent silica powder from clogging the purge nozzles 73. A high-pressure pulse blower is also installed on the main air intake pipe 71. It blows 0.6 MPa compressed air at high speed through the blow nozzle 73 onto the inner wall of the heat exchange tube 15, blowing off the silica powder accumulated in the heat exchange tube 15 and letting it fall into the ash discharge port 18 below. The ash discharge port 18 is controlled by an electric valve, which opens and closes automatically. After cleaning, the heat exchange core is used as a spare module to wait for the next operation.

[0022] The detection component 6 includes a pressure sensor installed on the exhaust gas inlet pipe 2 and the exhaust gas outlet pipe 3 to detect the pressure difference between them. It also includes a control component, in this embodiment a PLC, which is electrically connected to the first control valve 4, the second control valve 5, the pressure sensor, and the high-pressure pulse soot blower. When the pressure sensor detects that the pressure of the operating heat exchanger module 1 exceeds a set threshold, it indicates that the module needs cleaning. The signal is fed back to the PLC, which controls the first control valve 4 and the second control valve 5 on the standby module to open, and the control valves on the module requiring cleaning to close. The PLC then controls the high-pressure pulse soot blower on that module to operate for cleaning. This embodiment enables automatic switching between the working module and the standby module, as well as automatic cleaning operations, without requiring machine downtime, thus improving production efficiency. Example 2

[0023] Based on Embodiment 1, the purge pipe 72 of the dust removal assembly 7 is also equipped with an atomizing nozzle. The atomizing nozzle is connected to an external high-pressure water source. The external high-pressure water source can supply high-pressure water to the atomizing nozzle, so that the atomizing nozzle can spray a high-pressure water column or high-pressure steam at 1 MPa. After dust removal by compressed air, the inner wall of the heat exchange tube 15 can also be cleaned by high-pressure water column or high-pressure steam, further improving the cleaning effect of the heat exchange tube 15.

[0024] Specifically, the purge pipe 72 is configured with a double-layer pipe structure. The inner and outer pipes are connected to the purge nozzle 73 and the atomizing nozzle, respectively, and are also connected to an external air source and an external high-pressure water source, respectively. Thus, the dust removal assembly 7 has two cleaning systems: purge and flushing. These two systems can be used simultaneously or selectively, depending on the actual situation. Of course, the connections of the inner and outer pipes to the external air source and the external high-pressure water source can also be reversed without affecting actual use.

[0025] The above is the entire working process of the device, and all contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0026] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A modular heat exchanger assembly for a carbon fiber production line exhaust gas RTO incinerator, characterized in that, It includes four heat exchanger modules (1) connected in parallel. Each heat exchanger module (1) includes a body. A waste gas inlet pipe (2) is installed on one side of the body, and a waste gas outlet pipe (3) is installed on the other side of the body. A first control valve (4) is installed on the waste gas inlet pipe (2), and a second control valve (5) is installed on the waste gas outlet pipe (3). A detection component (6) for detecting blockage of the body is also installed on the body. A dust removal component (7) is installed on the side of the body facing the waste gas outlet pipe (3). Among them, the four heat exchanger modules (1) adopt a three-in-one-out operation mode. When the detection component (6) on one heat exchanger module (1) detects that the blockage reaches the threshold, the heat exchanger module (1) stops running and the standby heat exchanger module (1) is put into operation. The cleaning component (7) on the stopped heat exchanger module (1) performs cleaning work. After the cleaning is completed, the heat exchanger module (1) is switched to standby state.

2. The modular heat exchanger assembly for the carbon fiber production line exhaust gas RTO incinerator according to claim 1, characterized in that, The main body includes a shell, in which a plurality of heat exchange tubes (15) are vertically installed. An air inlet (16) is provided at the upper part of the shell, and the exhaust gas inlet pipe (2) is connected to the air inlet (16). An air outlet (17) is provided at the lower part of the shell, and the air outlet (17) is connected to the exhaust gas outlet pipe (3). An ash discharge port (18) is provided at the lower end of the shell, and the ash removal assembly (7) is installed inside the heat exchange tubes (15).

3. The modular heat exchanger assembly for the carbon fiber production line exhaust gas RTO incinerator according to claim 2, characterized in that, The dust removal assembly (7) includes an air inlet manifold (71) connected to an external source. The air outlet of the air inlet manifold (71) is provided with several purge pipes (72). The number of purge pipes (72) is the same as the number of heat exchange tubes (15), and they are inserted vertically into the heat exchange tubes (15). Several purge nozzles (73) are installed on the purge pipes (72). A third control valve (74) is installed on the air inlet manifold (71). The air inlet manifold (71) continuously supplies compressed air to the purge pipes (72) to keep the purge pipes (72) under positive pressure.

4. The modular heat exchanger assembly for the carbon fiber production line exhaust gas RTO incinerator according to claim 3, characterized in that, The purge pipe (72) is also equipped with an atomizing nozzle, which is connected to an external high-pressure water source.

5. The modular heat exchanger assembly for the carbon fiber production line exhaust gas RTO incinerator according to claim 2, characterized in that, The heat exchange tube (15) is a stainless steel tube with a diameter ≥ DN100mm.

6. The modular heat exchanger assembly for the carbon fiber production line exhaust gas RTO incinerator according to claim 1, characterized in that, The detection component (6) includes a pressure sensor, which is installed on the exhaust gas inlet pipe (2) and the exhaust gas outlet pipe (3) to detect the pressure difference between the exhaust gas inlet pipe (2) and the exhaust gas outlet pipe (3).

7. The modular heat exchanger assembly for the carbon fiber production line exhaust gas RTO incinerator according to claim 1, characterized in that, It also includes control components, all of which are electrically connected to the first control valve (4), the second control valve (5), the detection component (6), and the dust removal component (7).

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