Low-carbon low-energy-consumption novel coating workshop drying furnace system and method

Abstract

The invention discloses a low-carbon and low-energy-consumption novel coating workshop drying furnace system and method, and belongs to the technical field of automobile manufacturing. The problems of high carbon emission and low heat recovery efficiency are solved. According to the technical scheme, on the basis of the CL-DRM technology, CO2 waste gas generated in a combustion furnace serves as a raw material to participate in the CH4 reforming process, original CO2 emission is converted into a high-additional-value CO product, and the high-additional-value CO product can serve as a raw material of fuel or other chemical products subsequently. A large amount of heat energy generated by the heat accumulating type incinerator is recycled and used for maintaining energy needed by the CL-DRM reaction, and then an additional heat recycling step is added on the basis of a zeolite rotating wheel at the front end of the heat accumulating type incinerator, so that input energy consumption is reduced, and the energy utilization efficiency of the system is improved; and an auxiliary fuel (H2) and an oxidizing agent (O2) are provided for the combustion process by adopting a photovoltaic water electrolysis hydrogen production mode, so that high-purity CO2 tail gas can be conveniently captured and further converted and utilized while the energy utilization efficiency is improved by utilizing clean energy.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile manufacturing, and in particular to a new type of low-carbon and low-energy consumption paint shop drying furnace system and method. Background Art

[0002] The automobile paint shop is an important part of the automobile manufacturing production line. Its main work is to cover the metal or non-metal surface of the car with a protective layer or decorative layer. The entire coating production line is mainly composed of pre-treatment equipment, powder spraying system, paint spraying equipment, drying furnace, heat source system, electronic control system, exhaust gas treatment system, hanging conveyor chain and other systems. Among them, the drying furnace is one of the important equipment in the coating production line. The uniformity of its internal temperature largely determines the final quality of the coating; the heat source system mostly uses methane as fuel (a few are hydrogen, but the cost is higher), and the heat released in the combustion furnace can provide energy for the drying furnace by direct or indirect heating; the exhaust gas treatment system mostly uses a regenerative thermal incinerator (RTO), and its main function is to post-treat the volatile organic compounds (VOCs) generated during the coating drying process. For the convenience of expression, the above-mentioned three subsystems of drying furnace, heat source system, and exhaust gas treatment system are collectively referred to as the drying furnace system.

[0003] With the development of industrial technology, the current coating process has gradually developed in the direction of automation, but there are still some key issues in the design and application of drying furnace systems that have not been resolved. Two issues are focused on here: the first is the high carbon emission problem. For methane combustion furnaces, most of the current processes use air-assisted combustion, and the combustion products formed are mixed gases of CO2 and N2, which makes it difficult to capture and recycle CO2, and it can only be discharged into the atmosphere in the end, causing certain carbon emission costs to the company; the second is the low heat recovery efficiency problem. In the exhaust gas treatment system, the incineration temperature inside the RTO can usually reach more than 800°C, and the current mainstream heat recovery method is only to use part of the heat for the VOCs exhaust gas concentration process of the zeolite rotor at the front end of the RTO to save the incineration air supply. Even for some processes that have been industrialized, the heat generated by the incineration in the RTO is completely dissipated through natural convection, and there is no corresponding heat recovery step.

[0004] Therefore, it is urgent to propose a new type of low-carbon and low-energy drying furnace system and method for a paint shop to solve the problems of high carbon emissions and low heat recovery efficiency in the prior art. Summary of the invention

[0005] In view of the above facts, in order to solve the problems of high carbon emissions and low heat recovery efficiency in the prior art, the present invention further designs a new type of low-carbon and low-energy consumption paint shop drying furnace system and method.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] Solution 1: A new type of low-carbon and low-energy drying furnace system for a paint shop, including a mixed gas tank, a drying furnace, a zeolite rotor, a regenerative incinerator, a chimney, a combustion furnace, a CL-DRM reactor, a raw material tank, a photovoltaic electrolysis water device, and a mixed fuel tank;

[0008] The mixed gas tank, drying furnace, zeolite rotor, regenerative incinerator and chimney are connected in sequence;

[0009] The exhaust port of the drying furnace is connected to the mixed gas tank through a return air duct, and fresh air is introduced into the mixed gas tank;

[0010] The raw material tank is connected to the CL-DRM reactor, the exhaust port of the CL-DRM reactor is connected to the mixed fuel tank, and the exhaust port of the photovoltaic water electrolysis device is connected to the mixed fuel tank;

[0011] The mixed fuel tank is connected to the combustion furnace, and the exhaust port of the combustion furnace is connected to the CL-DRM reaction furnace;

[0012] The combustion furnace is connected to the mixed gas tank via a heat exchanger;

[0013] The regenerative incinerator and the zeolite rotor are connected via a first heat recovery pipeline;

[0014] The regenerative thermal incinerator and the CL-DRM reactor are connected via a second heat recovery pipeline.

[0015] Solution 2: A new method for realizing a low-carbon and low-energy drying furnace in a paint shop, the specific steps are as follows:

[0016] Step 1: CH4 raw gas is cracked by the catalyst inside the CL-DRM reactor to produce synthesis gas, and the regenerative incinerator maintains the required temperature of the CL-DRM reactor through heat recovery;

[0017] Step 2: The synthesis gas produced in step 1 is mixed with the gas produced by the photovoltaic water electrolysis device in a mixed fuel tank and transported to a combustion furnace for combustion and heat release;

[0018] Step 3: Fresh air and return air from the drying furnace form a mixed gas. The combustion furnace indirectly heats the mixed gas to the set temperature and then transports it to the drying furnace for drying. When the VOCs generated in the process reach a certain concentration, the waste gas is discharged. The waste gas enters the zeolite wheel for further concentration.

[0019] Step 4: The mixed gas carrying high concentration of VOCs is transported to the regenerative incinerator for incineration, generating a high temperature of 800-1100°C. A small amount of heat is recovered through the first heat recovery pipeline and provides energy to the zeolite wheel through the heat exchanger. Most of the heat is recovered through the second heat recovery pipeline to maintain the temperature conditions required for the CL-DRM reactor reaction.

[0020] Step 5: Since the mixed fuel formed in step 2 directly uses oxygen as the oxidant, the H2O and CO2 produced in the combustion process are high-purity tail gas. This part of the tail gas is dried to obtain high-purity CO2, which is transported to the CL-DRM reactor for catalyst regeneration reaction to obtain high-purity CO, which is then recycled.

[0021] Furthermore: the catalyst inside the CL-DRM reactor is iron-based, nickel-based, or cerium-based metal oxides, and the CH4 raw gas is cracked into a synthesis gas product containing CO and H2 in a ratio of 1:1.

[0022] Furthermore: the photovoltaic water electrolysis device produces H2 and O2.

[0023] The beneficial effects of the present invention are:

[0024] 1. The present invention introduces CL-DRM technology into the traditional methane direct combustion process to collect the CO2 tail gas originally discharged directly into the atmosphere and convert it into a high-purity CO product, saving the carbon emission cost of the enterprise. The energy released by the H2 and CO produced after CH4 reforming in combustion is almost the same as that of CH4 (the calorific value of 1 mol CH4 is 39.82MJ / m 3 , the total calorific value of 2mol H2+1molCO is 38.12MJ / m 3 ), so it basically does not affect the economic cost of combustion.

[0025] 2. The present invention mainly uses heat recovery energy in the process route of the CL-DRM process, which is feasible in terms of reaction principle and reaction conditions, improves heat recovery efficiency, and saves system energy consumption costs.

[0026] 3. The present invention adopts photovoltaic electrolysis of water to produce hydrogen to provide fuel (H2) and oxidant (O2) for the combustion process, thereby improving energy utilization efficiency by utilizing clean energy while capturing high-purity CO2 tail gas for further conversion and utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a system structure diagram of the present invention;

[0028] Figure 2 It is a process flow chart of the present invention.

[0029] In the figure: 2-mixed gas tank, 3-drying furnace, 4-zeolite rotor, 5-regenerative incinerator, 6-chimney, 7-combustion furnace, 8-CL-DRM reactor, 9-raw material tank, 10-photovoltaic electrolysis water device, 11-mixed fuel tank. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0031] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0032] In the present application, the directions or positional relationships indicated by the terms "upper", "lower", "inner", "middle", "outer", "front", "back", etc. are based on the directions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction.

[0033] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0034] In addition, the terms "disposed", "connected", and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0036] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0037] Embodiment 1: A new type of low-carbon and low-energy drying furnace system for a coating workshop of this embodiment includes a mixed gas tank 2, a drying furnace 3, a zeolite wheel 4, a regenerative incinerator 5, a chimney 6, a combustion furnace 7, a CL-DRM reactor 8, a raw material tank 9, a photovoltaic electrolysis water device 10, and a mixed fuel tank 11;

[0038] The mixed gas tank 2, drying furnace 3, zeolite rotor 4, regenerative incinerator 5, and chimney 6 are connected in sequence;

[0039] The exhaust port of the drying furnace 3 is connected to the mixed gas tank 2 through a return air duct, and fresh air is introduced into the mixed gas tank 2;

[0040] The raw material tank 9 is connected to the CL-DRM reactor 8, the exhaust port of the CL-DRM reactor 8 is connected to the mixed fuel tank 11, and the exhaust port of the photovoltaic electrolysis water device 10 is connected to the mixed fuel tank 11;

[0041] The mixed fuel tank 11 is connected to the combustion furnace 7, and the exhaust port of the combustion furnace 7 is connected to the CL-DRM reaction furnace 8;

[0042] The combustion furnace 7 is connected to the mixed gas tank 2 via a heat exchanger;

[0043] The regenerative incinerator 5 and the zeolite rotor 4 are connected via a first heat recovery pipeline;

[0044] The regenerative thermal incinerator 5 and the CL-DRM reactor 8 are connected via a second heat recovery pipeline.

[0045] Embodiment 2: A method for realizing a new type of low-carbon and low-energy drying furnace in a paint shop of this embodiment, the specific steps are as follows:

[0046] Step 1: The CH4 feed gas is cracked by the catalyst inside the CL-DRM reactor 8 to produce syngas. The regenerative thermal oxidizer 5 maintains the temperature of the CL-DRM reactor 8 above 800 °C through heat recovery, providing the temperature condition for the chemical looping dry reforming reaction of CH4.

[0047] Step 2: The syngas produced in Step 1 is mixed with the gas produced by the photovoltaic electrolyzer 10 in the mixing fuel tank 11 and then transported to the combustion furnace 7 for combustion and heat release to heat the mixed gas transported into the drying furnace 3.

[0048] Step 3: Fresh air and the return air gas from the drying furnace 3 form a mixed gas. After the combustion furnace 7 indirectly heats the mixed gas to the set temperature, it is transported into the drying furnace 3 to dry the automotive coating by heat convection. When the VOCs generated during the process reach a certain concentration, the waste gas is discharged. After the waste gas enters the zeolite rotor 4 for concentration, the concentration of VOCs will be further increased.

[0049] Step 4: The mixed gas carrying high-concentration VOCs is transported to the regenerative thermal oxidizer 5 for incineration, generating a high temperature of 800 - 1100 °C. A small part of the heat is recovered through the first heat recovery pipeline and provided to the zeolite rotor 4 in the form of a heat exchanger, while most of the heat is recovered through the second heat recovery pipeline and used to maintain the temperature condition required for the reaction in the CL-DRM reactor 8.

[0050] Step 5: Since the mixed fuel formed in Step 2 directly uses oxygen as the oxidant, the H2O and CO2 generated during the combustion process are high-purity tail gases. After this part of the tail gas is dried, high-purity CO2 can be obtained, which is transported to the CL-DRM reactor 8 for the catalyst regeneration reaction to obtain high-purity CO and recycle it.

[0051] More specifically: The catalyst inside the CL-DRM reactor 8 is an iron-based, nickel-based, or cerium-based metal oxide. The CH4 feed gas is cracked into a syngas product containing CO and H2 in a ratio of 1:1.

[0052] More specifically: The photovoltaic electrolyzer 10 generates H2 and O2.

[0053] More specifically: The CL-DRM reaction equation can be expressed as:

[0054] The first step, reduction reaction (partial oxidation reaction of methane):

[0055] δCH4 + MO x →MO x-δ +δ(CO + 2H2) (I)

[0056] The second step, oxidation reaction (catalyst regeneration reaction):

[0057] δCO2+MO x-δ →MO x +δCO(II)

[0058] The overall reaction of the whole process is expressed as:

[0059] CH4+CO2→2CO+2H2(III)

[0060] Where δ represents the stoichiometric ratio of CH4 and CO2 during the reaction, and x is a positive number and is greater than δ.

[0061] More specifically: the surplus H2 generated by the photovoltaic water electrolysis device 10 can be stored or sold

[0062] More specifically: the CO product generated in step 5 is a high value-added carbon recovery product, which can generate profits through storage, combustion, reprocessing, sales, etc., thereby reducing the operating costs of the system.

[0063] More specifically: the CL-DRM reactor 8 is the place where the CH4 chemical chain dry reforming reaction occurs, and a large amount of heat energy generated by the incineration process of the regenerative incinerator 5 is recovered and can be used to maintain the energy required for the reaction process.

[0064] More specifically: CO and H2 generated in the first step of the CH4 chemical chain dry reforming reaction, and H2 and O2 generated by the photovoltaic water electrolysis device 10, are mixed and burned in the combustion furnace 7, and the heat generated is used to heat the mixed gas transported to the drying furnace 3.

[0065] More specifically: the body of the drying furnace 3 is generally made of high temperature resistant material to withstand high temperatures and maintain good sealing. The heat generated by the combustion furnace 7 heats the mixed gas to a set temperature and then transports it to the drying furnace 3 to dry the automobile coating by heat convection.

[0066] More specifically: after the exhaust gas enters the zeolite wheel 4, the zeolite material adsorbs the volatile organic compounds in the gas to concentrate it.

[0067] More specifically: the waste gas undergoes a high-temperature oxidation reaction in the regenerative heat incinerator 5, oxidizing and decomposing the VOCs organic waste gas into corresponding oxides and water; a small part of the heat generated by incineration is recovered to provide energy for the zeolite wheel 4, and most of the heat is used to maintain the energy required by the CL-DRM reactor 8.

[0068] More specifically: the photovoltaic water electrolysis device 10 utilizes solar energy to electrolyze water to generate H2 and O2, which are mixed with CO and H2 generated in the first step reaction and burned, and indirectly heat the mixed gas transported to the drying furnace.

[0069] More specifically: Since the combustion of the mixed fuel not only produces high-purity CO2 but also H2O, it needs to be dried and dehydrated, which can usually be done by condensation drying, adsorption drying or membrane separation technology.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents. As long as there is no structural conflict, the various features in the specific implementation methods disclosed in this application can be combined with each other in any way, and the essence of the corresponding technical solutions will not deviate from the scope of the technical solutions of the present invention.

[0071] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A new type of low-carbon and low-energy drying furnace system for paint shops, characterized in that: It includes a mixed gas tank (2), a drying furnace (3), a zeolite wheel (4), a regenerative incinerator (5), a chimney (6), a combustion furnace (7), a CL-DRM reaction furnace (8), a raw material tank (9), a photovoltaic electrolysis water device (10), and a mixed fuel tank (11); The mixed gas tank (2), drying furnace (3), zeolite rotor (4), regenerative incinerator (5), and chimney (6) are connected in sequence; The exhaust port of the drying furnace (3) is connected to the mixed gas tank (2) through a return air duct, and fresh air is introduced into the mixed gas tank (2); The raw material tank (9) is connected to the CL-DRM reactor (8), the exhaust port of the CL-DRM reactor (8) is connected to the mixed fuel tank (11), and the exhaust port of the photovoltaic water electrolysis device (10) is connected to the mixed fuel tank (11); The mixed fuel tank (11) is connected to the combustion furnace (7), and the exhaust port of the combustion furnace (7) is connected to the CL-DRM reaction furnace (8); The combustion furnace (7) is connected to the mixed gas tank (2) via a heat exchanger; The regenerative incinerator (5) and the zeolite rotor (4) are connected via a first heat recovery pipeline; The regenerative incinerator (5) and the CL-DRM reactor (8) are connected via a second heat recovery pipeline.

2. A method for realizing a new type of low-carbon and low-energy drying furnace in a paint shop, the specific steps are: Step 1: CH4 raw gas is cracked under the action of the catalyst inside the CL-DRM reactor (8) to produce synthesis gas, and at the same time, the regenerative incinerator (5) recovers heat through the second heat recovery pipeline to maintain the temperature required for the reaction of the CL-DRM reactor (8); Step 2: The synthesis gas generated in step 1 is mixed with the gas generated by the photovoltaic water electrolysis device (10) in a mixed fuel tank (11), and transported to the combustion furnace (7) to burn and release heat; Step 3: Fresh air and return air from the drying furnace (3) form a mixed gas, the combustion furnace (7) indirectly heats the mixed gas to a set temperature, and then transports it to the drying furnace (3) for drying. When the VOCs generated in the process reach a certain concentration, the waste gas is discharged, and the waste gas enters the zeolite wheel (4) to be further concentrated; Step 4: The mixed gas carrying high concentration of VOCs is transported to the regenerative incinerator (5) for incineration, and generates a high temperature of 800-1100°C. A small part of the heat is recovered through the first heat recovery pipeline and provides energy to the zeolite wheel (4) in the form of a heat exchanger. Most of the heat is recovered through the second heat recovery pipeline and is used to maintain the temperature conditions required for the reaction of the CL-DRM reactor (8); Step 5: The gas generated by the combustion furnace (7) in step 2 is dried and dehydrated to obtain high-purity CO2, which is then transported to the CL-DRM reactor (8) for catalyst regeneration reaction to obtain high-purity CO, which is then recycled.

3. The method for realizing a new type of low-carbon and low-energy consumption drying furnace in a paint shop according to claim 2, characterized in that: The catalyst inside the CL-DRM reactor (8) is an iron-based, nickel-based, or cerium-based metal oxide, and the CH4 raw gas is cracked into a synthesis gas product containing CO and H2 in a ratio of 1:

1.

4. The method for realizing a new type of low-carbon and low-energy drying furnace in a paint shop according to claim 2 is characterized in that: The photovoltaic water electrolysis device (10) produces H2 and O2.

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