Chemical looping conversion system and method for hydrocarbon fuel containing high-concentration CO2

Abstract

The invention provides a chemical looping conversion system and method for hydrocarbon fuel containing high-concentration CO2, and relates to the field of energy conversion, the system comprises a fuel reactor, a CO2 oxidation reactor, an absorbent regeneration reactor and an air reactor; the CO2-rich hydrocarbon fuel and the oxygen carrier are subjected to a complete oxidation reaction in the fuel reactor to generate a reduction-state oxygen carrier, carbon dioxide and water, and the carbon dioxide in the fuel reactor is absorbed by the absorbent; the absorbent after absorbing the carbon dioxide is subjected to desorption reaction in the absorbent regeneration reactor, the generated carbon dioxide enters the CO2 oxidation reactor, and the reduced oxygen carrier reacts with the carbon dioxide in the CO2 oxidation reactor to generate carbon monoxide and partially oxidized oxygen carrier; and the partially oxidized oxygen carrier is further oxidized by air in the air reactor and enters the fuel reactor again. Natural gas can be efficiently converted into carbon monoxide, meanwhile, self-heating balance of the system is achieved, and the extra energy supply requirement is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of energy conversion and utilization, and in particular to a method for 2 A system and method for chemical chain conversion of hydrocarbon fuels. Background Art

[0002] As the global energy transition progresses, natural gas, as a clean fuel, plays an increasingly important role in energy supply. However, the composition of natural gas varies significantly depending on its source. For example, biogas usually contains 23% to 50% carbon dioxide, the carbon dioxide concentration of South China Sea natural gas is between 20% and 80%, and shale gas also contains high concentrations of carbon dioxide. High carbon dioxide content poses a major challenge to natural gas transportation, efficient utilization, and carbon dioxide emission reduction. 2 The presence of carbon dioxide significantly reduces the energy density of natural gas, which directly affects its transportation and utilization efficiency. Traditional methods for processing carbon-containing natural gas usually rely on separating and removing carbon dioxide first to reduce its interference with subsequent conversion processes. Such decarbonization processes usually involve complex gas separation processes such as adsorption, membrane separation or chemical absorption. These methods are not only energy-intensive, but also cause energy waste and increase overall processing costs. At the same time, CO 2 The separation and capture process itself brings about certain greenhouse gas emissions, which fails to effectively reduce the environmental burden, but instead aggravates the greenhouse effect.

[0003] In carbon-containing natural gas conversion technology, traditional methane dry reforming (DRM) technology is a common method. 4 ) and carbon dioxide to produce synthesis gas (CO and H 2 ). However, the DRM process has obvious limitations. According to the stoichiometric relationship of the reaction, each mole of methane can only react with a maximum of one mole of carbon dioxide, which means that the process cannot effectively process natural gas with high concentrations of carbon dioxide. 2 The presence of carbon dioxide in high-concentration hydrocarbon fuel gas inhibits the hydrocarbon fuel conversion reaction, significantly reducing the hydrocarbon fuel conversion rate and the yield of synthesis gas. 2 It will also lead to sintering and carbon deposition of the catalyst, further affecting the stability and catalytic efficiency of the reaction. This not only reduces the purity of the synthesis gas, but also requires higher temperatures to maintain the reaction, thereby increasing energy consumption and carbon emissions, and cannot meet the current requirements for low-carbon technology.

[0004] Therefore, existing technologies have not been able to fully address the problem of high concentrations of CO 2The inhibitory effect on the conversion process of hydrocarbon fuels has also failed to effectively realize the high-value utilization of carbon dioxide. Therefore, it is necessary to develop a fuel cell that can efficiently convert high-concentration CO 2 The new conversion method of hydrocarbon fuel mixture has important practical significance and application value. Summary of the invention

[0005] In view of this, the present invention provides a method for 2 The hydrocarbon fuel chemical chain conversion system and method are designed to maximize the conversion and utilization of high-concentration CO 2 The system can convert high concentration CO 2 The hydrocarbon fuel mixture is efficiently converted into carbon monoxide, while achieving system self-heating balance, avoiding the need for additional energy supply.

[0006] The present application provides the following technical solutions: a method containing high concentration of CO 2 The hydrocarbon fuel chemical chain conversion system includes: fuel reactor, CO 2 oxidation reactor, absorbent regeneration reactor, and air reactor;

[0007] The fuel reactor is provided with an oxygen carrier inlet, an absorbent inlet and a port for introducing high concentration CO 2 The fuel inlet of the hydrocarbon fuel mixture is connected to the first outlet of the fuel reactor and the inlet of the separation device, and the first outlet of the separation device is connected to the CO 2 The first inlet of the oxidation reactor is connected to introduce the reduced oxygen carrier into the CO 2 In the oxidation reactor, the second discharge port of the separation device is connected to the inlet of the absorbent regeneration reactor to absorb CO 2 The absorbent after the step of heating is introduced into the absorbent regeneration reactor;

[0008] The first outlet of the absorbent regeneration reactor is connected to the absorbent inlet of the fuel reactor through a riser, and the second outlet of the absorbent regeneration reactor is connected to the CO 2 The second inlet connection of the oxidation reactor is used to desorb the CO 2 The introduction of the CO 2 In the oxidation reactor;

[0009] The CO 2 The first outlet of the oxidation reactor is connected to the first inlet of the air reactor for introducing the partially oxidized oxygen carrier into the air reactor. 2 The second outlet of the oxidation reactor is used to output the product CO;

[0010] Air is introduced into the second inlet of the air reactor, and the outlet of the air reactor is connected to the oxygen carrier inlet of the fuel reactor through the lifting pipe; a heat conduction device is arranged between the air reactor and the absorbent regeneration reactor for conducting the reaction heat generated in the air reactor to the absorbent regeneration reactor.

[0011] According to one embodiment of the present application, a CO purification system is also included, and the inlet of the CO purification system is connected to the CO 2 The second outlet of the oxidation reactor is connected to the CO mixed with the product CO 2 The first outlet of the CO purification system is separated from the CO 2 The third inlet connection of the oxidation reactor is used to transfer the separated CO 2 The introduction of the CO 2 In the oxidation reactor, the second outlet of the CO purification system is used to output the purified final product CO.

[0012] According to an embodiment of the present application, the CO purification system adopts a pressure swing adsorption device.

[0013] According to one embodiment of the present application, a gas-liquid separator is further included, the inlet of the gas-liquid separator is connected to the second outlet of the fuel reactor, and is used to introduce the water vapor generated in the fuel reactor into the gas-liquid separator, and the first outlet of the gas-liquid separator is connected to the CO 2 The fourth inlet connection of the oxidation reactor is used to remove CO mixed with water vapor. 2 After separation, the CO 2 In the oxidation reactor, the second outlet of the gas-liquid separator is used to discharge the separated water.

[0014] According to one embodiment of the present application, the fuel inlet of the fuel reactor is arranged at the bottom of the fuel reactor, the oxygen carrier inlet is arranged at the top of the fuel reactor, and the absorbent inlet is arranged in the middle of the fuel reactor.

[0015] According to an embodiment of the present application, the oxygen carrier is an iron-based oxygen carrier.

[0016] According to an embodiment of the present application, the absorbent comprises CaO, Li 4 SiO 4 , any one of hydrotalcite-like substances.

[0017] According to one embodiment of the present application, it also includes a feeding device, which is connected to the lifting pipe and is used to add oxygen carriers and absorbents.

[0018] According to one embodiment of the present application, a preheater is further included, the fuel inlet of the fuel reactor, the CO 2 The preheater is respectively arranged at the fourth inlet of the oxidation reactor and the second inlet of the air reactor.

[0019] The present application also provides a method as described above containing high concentration CO 2 A fuel conversion method of a hydrocarbon fuel chemical chain conversion system, comprising:

[0020] High concentration CO is fed into the fuel reactor through the fuel inlet. 2 The hydrocarbon fuel mixture is fed into the oxygen carrier through the oxygen carrier inlet of the fuel reactor, and the absorbent is fed into the absorbent inlet of the fuel reactor, so that the hydrocarbon fuel mixture and the oxygen carrier undergo a complete oxidation reaction in the fuel reactor to produce a reduced oxygen carrier, carbon dioxide and water, and the carbon dioxide in the fuel reactor is absorbed by the absorbent;

[0021] After absorbing carbon dioxide, the absorbent enters the absorbent regeneration reactor to undergo a desorption reaction, and the generated carbon dioxide passes through the CO 2 The second inlet of the oxidation reactor enters the CO 2 In the oxidation reactor, the desorbed absorbent re-enters the fuel reactor through the absorbent inlet of the fuel reactor to participate in the next cycle;

[0022] The reduced oxygen carrier enters the CO 2 In the oxidation reactor, the CO 2 The carbon dioxide in the oxidation reactor reacts to produce carbon monoxide and partially oxidized oxygen carrier;

[0023] The partially oxidized oxygen carrier enters the air reactor, is further oxidized by the air in the air reactor, and then re-enters the fuel reactor through the oxygen carrier inlet of the fuel reactor to participate in the next cycle; the heat generated in the air reactor is transferred to the absorbent regeneration reactor through a heat conduction device.

[0024] Compared with the prior art, the at least one technical solution adopted in the embodiments of this specification can achieve the following beneficial effects:

[0025] 1. In the embodiment of the present invention, high concentration CO is continuously introduced into the reaction stage of the fuel reactor. 2The hydrocarbon fuel mixture is adsorbed by an absorbent to the carbon dioxide produced by the oxidation of the fuel, so that the reaction moves toward the direction of producing water and carbon dioxide, increasing the reduction depth of the oxygen carrier while achieving complete oxidation of methane. The source separation of the hydrocarbon components in the hydrocarbon fuel mixture is achieved through simple condensation and water removal. The entire reaction process realizes the production of a single gas, carbon monoxide, avoiding the separation and purification of multiple product gases in traditional processes.

[0026] 2. Absorption of CO by absorbent in fuel reactor according to the present invention 2 The exothermic process and the endothermic process of methane oxidation occur simultaneously, stabilizing the temperature of the reactor and avoiding carbon deposition caused by endothermic cooling of methane oxidation in the traditional chemical chain methane reforming process.

[0027] 3. The embodiment of the present invention adopts a CO purification system to improve CO 2 The conversion rate not only produces high-quality carbon monoxide gas, but also improves the utilization rate of greenhouse gas carbon dioxide. The obtained carbon monoxide can be used as chemical raw materials or directly burned for heating and power generation, which is more valuable than the traditional process of pressure swing adsorption for product purification.

[0028] 4. In the embodiment of the present invention, the energy released by the oxidation of the oxygen carrier drives the regeneration of the absorbent, thereby achieving the self-heating balance of the system and avoiding the additional energy consumption caused by the traditional process of fully oxygen-combusting the gas fuel to provide regeneration energy.

[0029] 5. The invention has excellent flexibility and high adaptability. It can process various types and qualities of hydrocarbon fuel resources and can be adjusted according to specific needs. By adjusting the circulation flow of oxygen carriers and absorbents, and changing the feed inlet to directly process carbon dioxide, the technology can respond to requirements in different situations. The invention can function in different industrial environments and hydrocarbon fuel resource conditions, and provides a more flexible and sustainable way to reduce carbon emissions.

[0030] 6. The system of the present invention is effective in converting high concentration CO 2 When it comes to hydrocarbon fuel mixtures, it shows higher efficiency and lower environmental impact than the traditional DRM process system, and has significant technical advantages and application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 The embodiment of the present invention contains high concentration CO 2 A first structural diagram of a hydrocarbon fuel chemical chain conversion system;

[0033] Figure 2 The embodiment of the present invention contains high concentration CO 2 A second structural diagram of a hydrocarbon fuel chemical chain conversion system;

[0034] Figure 2 In the reactor, R1 is the fuel reactor, R2 is the CO 2 Oxidation reactor, R3-air reactor, R4-absorbent regeneration reactor, F1-high concentration CO 2 Hydrocarbon fuel mixture, F2-air, F3-water, F4-CO gas, F5-high temperature oxygen-poor gas, F6-H 2 O、CO 2 , a small amount of CO, a small amount of unreacted gas, F7-CO 2 , a small amount of CO, a small amount of unreacted gas, F8-separated CO 2 , F9-CO, CO 2 Gas, F10-CO 2 , S1-oxygen carrier, S2-absorbent, S3-reduced oxygen carrier and fixed CO 2 absorbent, S4-reduced oxygen carrier, S5-fixed CO 2 The absorbent, S6- is a partially oxidized oxygen carrier;

[0035] Figure 3 The embodiment of the present invention contains high concentration CO 2 Process schematic diagram of hydrocarbon fuel chemical chain conversion system;

[0036] Figure 3 In the figure, 1-absorbent, 2-oxygen carrier, 3-feeding equipment, 4-lift pipe, 5-gravity lifting device, 6-second cyclone separator, 7-gas-liquid separator, 8-fuel reactor, 9-first cyclone separator, 10-CO 2 Oxidation reactor, 11-pressure swing adsorption device, 12-mixing valve, 13-absorbent regeneration reactor, 14-air reactor, 15-first preheater, 16-second preheater, 17-third preheater. DETAILED DESCRIPTION

[0037] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0038] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0039] like Figure 1 As shown, the embodiment of the present invention provides a high concentration of CO 2 The hydrocarbon fuel chemical chain conversion system includes: fuel reactor, CO 2 oxidation reactor, absorbent regeneration reactor, and air reactor;

[0040] The fuel reactor is provided with an oxygen carrier inlet, an absorbent inlet and a port for introducing high concentration CO 2 The fuel inlet of the hydrocarbon fuel mixture is connected to the first outlet of the fuel reactor and the inlet of the separation device, and the first outlet of the separation device is connected to the CO 2 The first inlet of the oxidation reactor is connected to introduce the reduced oxygen carrier into the CO 2 In the oxidation reactor, the second discharge port of the separation device is connected to the inlet of the absorbent regeneration reactor to absorb CO 2 The absorbent after the step of heating is introduced into the absorbent regeneration reactor;

[0041] The first outlet of the absorbent regeneration reactor is connected to the absorbent inlet of the fuel reactor through a riser, and the second outlet of the absorbent regeneration reactor is connected to the CO 2 The second inlet connection of the oxidation reactor is used to desorb the CO 2 The introduction of the CO 2 In the oxidation reactor;

[0042] The CO 2 The first outlet of the oxidation reactor is connected to the first inlet of the air reactor for introducing the partially oxidized oxygen carrier into the air reactor. 2 The second outlet of the oxidation reactor is used to output the product CO;

[0043] Air is introduced into the second inlet of the air reactor, and the outlet of the air reactor is connected to the oxygen carrier inlet of the fuel reactor through the lifting pipe; a heat conduction device is arranged between the air reactor and the absorbent regeneration reactor for conducting the reaction heat generated in the air reactor to the absorbent regeneration reactor.

[0044] In order to increase CO 2 The conversion rate can not only obtain high-quality carbon monoxide gas, but also improve the utilization rate of greenhouse gas carbon dioxide. The obtained carbon monoxide can be used as chemical raw materials or directly burned for heating, power generation, etc. In one embodiment of the present invention, a CO purification system is also included, and the inlet of the CO purification system is connected to the CO 2 The second outlet of the oxidation reactor is connected to the CO mixed with the product CO 2 The first outlet of the CO purification system is separated from the CO 2 The third inlet connection of the oxidation reactor is used to transfer the separated CO 2 The introduction of the CO 2 In the oxidation reactor, the second outlet of the CO purification system is used to output the purified final product CO. In a specific implementation of this embodiment, the CO purification system adopts a pressure swing adsorption (PSA) device. The CO concentration before entering the purification system is about 30% to 40%, and its main component is CO 2 and CO.

[0045] In one embodiment of the present invention, a gas-liquid separator is further included, the inlet of the gas-liquid separator is connected to the second outlet of the fuel reactor, and is used to introduce the water vapor generated in the fuel reactor into the gas-liquid separator, and the first outlet of the gas-liquid separator is connected to the CO 2 The fourth inlet connection of the oxidation reactor is used to remove CO mixed with water vapor. 2 After separation, the CO 2 In the oxidation reactor, the second outlet of the gas-liquid separator is used to discharge the separated water; the gas after the reaction is condensed and separated to obtain pure carbon dioxide.

[0046] In order to allow the reactants to fully react in the fuel reactor, in one embodiment of the present invention, the fuel inlet of the fuel reactor is arranged at the bottom of the fuel reactor, the oxygen carrier inlet is arranged at the top of the fuel reactor, and the absorbent inlet is arranged in the middle of the fuel reactor, so that the oxygen carrier and the absorbent flow in the countercurrent to the fuel gas to ensure that the reaction is fully carried out.

[0047] According to some embodiments of the present invention, there is provided a method for producing a high concentration of CO 2The chemical chain conversion system of hydrocarbon fuels includes absorption enhancement reduction reaction process, CO 2 Oxidation process, air oxidation process and absorbent regeneration reaction process.

[0048] In the absorption enhanced reduction reaction process: high concentration CO 2 The hydrocarbon fuel mixture reacts with the oxidized oxygen carrier to generate carbon dioxide and water, the oxygen carrier is reduced to a reduced state, and the absorbent absorbs the generated carbon dioxide; thus, the methane conversion rate is increased and the reduction depth of the oxygen carrier is deepened.

[0049] In CO 2 During the oxidation process: the generated carbon dioxide reacts with the reduced oxygen carrier to produce carbon monoxide, while the oxygen carrier is partially oxidized;

[0050] In the air oxidation process: the oxygen carrier reacts with oxygen in the air and is completely oxidized to its initial state, forming a chemical chain cycle;

[0051] During the absorbent regeneration reaction: In the absorbent regeneration reactor, the carbon dioxide in the absorbent is desorbed by the heat released by the air oxidation reaction, so that the absorbent is restored to its initial state. The required heat is provided by the heat released by the air oxidation reaction process, so that the absorbent is restored to its initial state and the next cycle is carried out. In addition, the heat released by the air oxidation reaction also heats the oxygen carrier particles. The heated oxygen carrier particles enter the fuel reactor and release their own sensible heat to meet the thermal load demand of the fuel reactor. The fuel reactor can operate self-heating without the need for external combustion heating or electric heating.

[0052] In some specific implementations of the embodiments of the present invention, the oxygen carrier of this embodiment is an iron-based oxygen carrier. In practical applications, in order to improve the reaction kinetics and make the oxygen carrier have better reaction activity, an iron-based oxygen carrier with different supporting materials can be selected, or other composite materials containing iron can be selected.

[0053] Among them, the high concentration of CO 2 The hydrocarbon fuel mixture chemical chain fuel conversion method uses CO 2 The absorbent reacts with the CO in the reaction product 2 Absorption is performed to promote complete oxidation of hydrocarbon fuel mixture. Specifically, the optional absorbents include CaO, Li 4 SiO 4 , hydrotalcite, etc. This type of absorbent has a high 2 The absorption performance is good, and CO can be converted into 2 Desorption is simple. Taking CaO as an example, it reacts with CO 2 The absorption reaction is shown as follows: CaO + CO 2=CaCO 3 .

[0054] Among them, the high concentration of CO 2 The chemical chain fuel conversion method for hydrocarbon fuel mixture also includes the following steps: 2 After the oxidation reaction is completed, the absorbed CO 2 The desorption step is carried out, and the desorption method is adjusted according to the selected absorbent. 2 To destroy the chemical balance of the reduction reaction, while achieving complete oxidation of the hydrocarbon fuel mixture, deepen the reduction depth of the oxygen carrier, thereby increasing the subsequent CO 2 CO in oxidation reaction 2 Conversion rate and product CO purity. The absorbent absorbs CO 2 The heat released by the reaction is used to meet the endothermic demand of methane oxidation, which effectively alleviates the carbon deposition caused by endothermic cooling during methane oxidation, promotes the forward movement of the reaction, reduces the reaction temperature, and further reduces the demand for heat source grade of the endothermic reduction reaction.

[0055] Among them, the oxygen carrier and absorbent made into spherical particles circulate in the moving bed. The gas and solid particles flow in the opposite direction to ensure that the reaction gas can fully contact and react with the oxygen carrier. By controlling the reaction raw materials and reaction conditions at different stages, the hydrogenation products in methane are removed during the reduction of the oxygen carrier, and a single carbon monoxide is produced during the oxidation of the oxygen carrier by carbon dioxide. The whole process achieves high CO through the circulation of the oxygen carrier and absorbent in the moving bed. 2 The conversion and separate production of carbon monoxide reduce greenhouse gas emissions and fully improve the utilization rate of reactants.

[0056] This system can be used for biogas, shale gas, combustible ice and other high-concentration CO 2 The conversion and utilization of hydrocarbon fuel mixture can also change the circulation flow of oxygen carrier and absorbent according to the different types and qualities of hydrocarbon fuel mixture resources introduced, and directly use it for CO 2 The invention brings more possibilities to the energy industry and provides a more flexible and sustainable way to reduce carbon emissions.

[0057] In one embodiment of the present invention, the system further comprises a feeding device, which is connected to the riser and is used for adding oxygen carriers and absorbents.

[0058] In one embodiment of the present invention, the system includes a preheater, a fuel inlet of the fuel reactor, the CO 2 The preheater is respectively arranged at the fourth inlet of the oxidation reactor and the second inlet of the air reactor.

[0059] In one embodiment of the present invention, the CO 2 The oxidation reactor is also equipped with a separate CO 2 Inlet, when converting low concentration CO 2 When using hydrocarbon fuel, CO 2 The oxidation reactor can also convert additional CO 2 .

[0060] In one embodiment of the present invention, the separation device is a cyclone separator.

[0061] like Figure 3 As shown, in the embodiment of the present invention, the high concentration of CO 2 In hydrocarbon fuel conversion systems, high concentrations of CO 2 Natural gas is the inlet gas of the fuel reactor 8. It is preheated by the first preheater 15 and then fed into the bottom of the fuel reactor 8. The solid oxygen carrier 2 and absorbent 1 particles enter through the feeding device 3, are lifted by the lifting pipe 4 and the gravity lifting device 5, and then enter from the top and the middle of the fuel reactor 8 respectively after passing through the second cyclone separator 6, and flow in the opposite direction to the gas. In the fuel reactor 8, the natural gas reacts with the oxidized oxygen carrier 2. During the reaction, the oxygen carrier 2 will be converted into a reduced state, and the methane in the natural gas will be converted into carbon dioxide and water. At the same time, the spherical absorbent 1 in the fuel reactor 8 will absorb the carbon dioxide generated in the reaction, thereby increasing the methane conversion rate and deepening the reduction depth of the oxygen carrier. After the absorbent 1 fixed with carbon dioxide and the reduced oxygen carrier 2 are separated by the first cyclone separator 9 at the outlet of the fuel reactor 8, they enter the absorbent regeneration reactor 13 and the CO2 regeneration reactor 14 respectively. 2 In the absorbent regeneration reactor 13, the spherical absorbent 1 undergoes desorption and produces carbon dioxide, which is introduced into the CO 2 The regenerated absorbent 1 reacts with the reduced oxygen carrier in the oxidation reactor 10, and the regenerated absorbent 1 is introduced into the riser 4 to participate in the next cycle. 2 A pressure swing adsorption device 11 is provided at the outlet of the oxidation reactor 10 to separate CO and CO in the product. 2 and reintroducing the resulting carbon dioxide into CO 2 The oxidation reactor 10 performs internal circulation to increase the CO 2 Conversion rate. 2After the oxidation reactor 10, the partially oxidized oxygen carrier 2 will enter the air reactor 14, where the oxygen in the air will completely oxidize and regenerate the oxygen carrier, and the heat generated will be used for the absorbent regeneration reactor 13 through heat conduction; after leaving the air reactor 14, the oxygen carrier 2 will enter the riser 4 to continue the next cycle, forming a chemical chain cycle. The air inlet of the air reactor 14 is provided with a third preheater 17, and the water vapor discharged from the fuel reactor 8 is separated by the gas-liquid separator 7, and the separated CO 2 After being preheated by the second preheater 16, it enters the CO 2 Oxidation reactor 10, CO 2 The inlet of the oxidation reactor 10 is accessed by a mixing valve 12 .

[0062] Among them, the high concentration of CO 2 The hydrocarbon fuel conversion system is not only suitable for the conversion of high-concentration carbon dioxide natural gas, but also for the conversion and utilization of pure carbon dioxide. In this system, additional carbon dioxide can enter from the bottom of the carbon dioxide oxidation reactor and react with the oxygen carrier in a reduced state to generate carbon monoxide.

[0063] The embodiment of the present invention provides a method for efficiently converting high-concentration CO 2 In order to demonstrate the performance of the system, the use of the system to treat CO 2 The performance data of natural gas with a concentration of 63.5% is compared with the traditional DRM (dry reforming) system. The calculation results are shown in Table 1, where M R Indicates the converted CO 2 CH 4 The molar flow ratio reflects the system's ability to directly process high-concentration carbon dioxide natural gas. and Indicates the system processes CO per unit mole 2 CO from natural gas 2 The moles of methane emitted and the additional moles of methane burned. CO Indicates the purity of CO at the system outlet. η c and η e They represent the energy efficiency and efficiency.

[0064] Specifically, M. R , P CO The calculation method is as follows:

[0065]

[0066] Among them, n i-in(FR) and n i Represents the fuel reactor and CO2 The molar flow rate of each gas at the outlet of the oxidation reactor, i represents H 2 , H 2 O, CO, CO 2 , or CH 4 .

[0067] Specifically, η c , η e The calculation method is as follows:

[0068]

[0069] E sep represents the equivalent power consumption of PSA in the system, where R is the gas constant, 8.314 J / (mol·K), T 0 is 298.15K, It is the CO in the pre-treatment gas. 2 Concentration, η sep is the separation efficiency, which is 0.3.

[0070]

[0071] Among them, E out,total is the total effective energy of the system output, E out,total is the total effective energy of the input system. Specifically, the effective energy (E) of each stream in the system can be calculated by the following formula:

[0072] E=E chem +E phy

[0073]

[0074] E phy =∑x i [(HH 0 )-T 0 (SS 0 )] i

[0075] Among them, x i is the molar fraction of component i, is the standard chemical molar exergy, as shown in Table 1. H and S are the molar enthalpy and entropy, respectively; H 0 and S 0 represents the standard molar enthalpy and entropy at reference conditions. In this study, the temperature and pressure of the environment are 25 °C and 1 atm, respectively.

[0076] From the comparison results, it can be seen that the CLR-CR system is superior to the traditional DRM system in many key indicators. Under the action of the absorbent, the new system can work under self-heating equilibrium conditions, while the DRM system needs to operate at a high temperature of 800°C. Compared with DRM, the CLR-CR system can reduce CO per unit of methane. 2 The capacity was increased from 0.76 to 1.71, achieving the goal of 2 CO in natural gas 2 The energy efficiency and The efficiency is 89.56% and 82.54%, respectively, which is 15.64% and 14.85% higher than that of the DRM system. In addition, under the action of the absorbent, the CLR-CR system is able to achieve self-thermal balance without the need for additional methane combustion heating, thereby preventing the generation of additional carbon dioxide emissions. In contrast, for every mole of carbon-containing natural gas processed by the conventional DRM, 0.25 moles of methane are consumed and 0.42 moles of carbon dioxide are emitted. In summary, the system of the present invention is superior in converting high-concentration CO 2 When using natural gas, it shows higher efficiency and lower environmental impact, and has significant technical advantages and application prospects.

[0077] Table 1 Comparison of performance parameters between DRM system and CLR-CR system

[0078]

[0079] The present invention also provides a high concentration CO 2 A method for converting hydrocarbon fuels, comprising:

[0080] High concentration CO is fed into the fuel reactor through the fuel inlet. 2 The hydrocarbon fuel mixture is fed into the oxygen carrier through the oxygen carrier inlet of the fuel reactor, and the absorbent is fed into the absorbent inlet of the fuel reactor, so that the hydrocarbon fuel mixture and the oxygen carrier undergo a complete oxidation reaction in the fuel reactor to produce a reduced oxygen carrier, carbon dioxide and water, and the carbon dioxide in the fuel reactor is absorbed by the absorbent;

[0081] After absorbing carbon dioxide, the absorbent enters the absorbent regeneration reactor to undergo a desorption reaction, and the generated carbon dioxide passes through the CO 2 The second inlet of the oxidation reactor enters the CO 2 In the oxidation reactor, the desorbed absorbent re-enters the fuel reactor through the absorbent inlet of the fuel reactor to participate in the next cycle;

[0082] The reduced oxygen carrier enters the CO 2 In the oxidation reactor, the CO 2 The carbon dioxide in the oxidation reactor reacts to produce carbon monoxide and partially oxidized oxygen carrier;

[0083] The partially oxidized oxygen carrier enters the air reactor, is further oxidized by the air in the air reactor to increase its temperature, and re-enters the fuel reactor through the oxygen carrier inlet of the fuel reactor to participate in the next cycle; the heat generated in the air reactor is transferred to the absorbent regeneration reactor through a heat conduction device.

[0084] In one embodiment of the present invention, the oxygen carrier is Fe 2 O 3 / Al 2 O 3 , where Al 2 O 3 Acting as a carrier, Fe 2 O 3 As a reactant, CO 2 CaO is selected as the absorbent. The main reactions and the overall system reactions occurring in each process are shown in the following equations (1)-(5) and (6), respectively:

[0085] 4Fe 2 O 3 +CH 4 =CO 2 +8FeO+2H 2 O (1)

[0086] 3FeO+CO 2 =CO+Fe 3 O 4 (2)

[0087] 4Fe 3 O 4 +O 2 =6Fe 2 O 3 (3)

[0088] CO 2 +CaO= CaCO 3 (4)

[0089] CaCO 3 =CO 2 +CaO (5)

[0090] CH 4 +O 2 +CO 2 =CO+H 2 O (6)

[0091] Absorbent CaO and oxygen carrier Fe 2 O 3 / Al 2 O 3 Under the action of gravity and lifting equipment, it is separated by a cyclone separator and then enters the fuel reactor. After reacting with the fuel gas in the fuel reactor, it enters the cyclone separator again for separation. The obtained absorbent with fixed carbon dioxide enters the absorbent regeneration reaction for regeneration, while the oxygen carrier particles are successively regenerated by CO 2 The oxidation reactor and the air reactor finally enter the riser together with the regenerated absorbent to repeat the above process to complete a cycle. The water produced in the fuel reactor is discharged from the system, and CO 2 The carbon monoxide produced in the oxidation reactor is discharged from the top of the reactor and is collected and stored after separation by PSA pressure swing adsorption.

[0092] The entire system cycle process mainly includes the following three stages: the first stage is the high concentration of CO in the fuel reactor 2 The oxidation process of hydrocarbon fuels occurs simultaneously with the reduction of oxygen carriers and CO 2 The second stage is the process of desorption of carbon dioxide and production of carbon monoxide. The absorbent will desorb carbon dioxide, and the carbon dioxide produced in the fuel reactor will be reduced to carbon monoxide by the reduced oxygen carrier. The third stage is the oxidation stage of the oxygen carrier, and the lifting process of the oxygen carrier and absorbent particles is completed at the same time.

[0093] like Figure 2 As shown, first, open the valve, high concentration CO 2 The hydrocarbon fuel mixture F1 flows into the bottom of the fuel reactor R1, and the oxygen carrier S1 (Fe 2 O 3 / Al 2 O 3 ) and absorbent S2(CaO) will enter from the top and middle of the reactor respectively, and the reaction gas and solid particles will flow in reverse, so that the reaction gas methane and carbon dioxide can fully contact and react with the oxygen carrier and absorbent. In this stage, a reduction reaction as shown in formula (1) will occur, and the oxidized ferric oxide will react with methane to produce carbon dioxide and water, while the oxidized iron-based oxygen carrier will be reduced to the reduced oxygen carrier S4 ferrous oxide. At this time, the calcium oxide absorbent flowing in with the oxygen carrier will in situ adsorb the generated carbon dioxide to generate fixed CO 2 The absorbent S5 undergoes an absorption reaction as shown in formula (4). According to the equilibrium principle of chemical reactions, the reduction of carbon dioxide in the reaction system will inevitably promote the methane oxidation reaction to move toward the direction of producing carbon dioxide and water, thereby increasing the methane conversion rate and water yield. Finally, the H2 O、CO 2 , a small amount of CO, and a small amount of unreacted gas F6 are simply cooled after heat exchange to remove water F3 from the reaction system, CO 2 , a small amount of CO, and a small amount of unreacted gas F7 are reintroduced into CO 2 Oxidation reactor R2. In this step, the source separation of hydrocarbon components in the fuel is achieved. At the same time, the addition of absorbent changes the equilibrium conditions of the reaction system and produces adsorption reaction to release heat, stabilizing the operating temperature of the reactor.

[0094] After the first stage, the reduced oxygen carrier and the fixed CO 2 Absorbent S3(FeO / Al 2 O 3 and CaCO 3 ) enters the cyclone separator for separation, and then enters the absorbent regeneration reactor R4 and CO 2 Oxidation reactor R2. The absorbent in the absorbent regeneration reactor R4 desorbs and releases CO 2 F10, the product gas of fuel reactor R1 is condensed and dehydrated, and then enters the CO2 desorbed by the absorbent together. 2 Oxidation reactor R2. In this stage, CO will occur as shown in formula (2) 2 Oxidation reaction, the reduced ferrous oxide reacts with carbon dioxide to produce carbon monoxide, and the ferrous oxide is oxidized to ferroferric oxide. Due to the limitation of the single-step conversion rate of this reaction, CO 2 The outlet gas of oxidation reactor R2 is mixed with some unreacted CO 2 , in order to increase CO 2 Utilization rate, CO and CO at the reactor outlet 2 After the gas F9 is separated by the pressure swing adsorption device, the separated CO 2 F8 is reintroduced into the reactor to participate in the reaction, and CO gas F4 is discharged and collected.

[0095] After the second stage of reaction, the reduced ferrous oxide is oxidized to ferroferric oxide by carbon dioxide, and the partially oxidized oxygen carrier S6 then enters the air reactor R3. The preheated air is fed into the bottom of the air reactor R3 to oxidize the ferroferric oxide to ferric oxide (Formula (3)). At the same time, the heat generated is supplied to the absorbent regeneration reactor R4 through heat conduction to regenerate the absorbent. In the absorbent regeneration reactor R4, the carbon dioxide generated by the thermal decomposition of calcium carbonate is fed into the CO 2 The oxidation reactor R2 participates in the reaction (Formula (5)).

[0096] After passing through the air reactor R3, the oxygen carrier is oxidized and then recycled and regenerated, and enters the riser together with the absorbent, and after being lifted, flows into the fuel reactor R1 for the next cycle.

[0097] In the whole system, the recycling of heat energy is achieved through the circulation of oxygen carrier S1 and absorbent S2 and the coupling between different processes. The high-temperature gas from the outlet of fuel reactor R1 is first used to import high-concentration CO 2 The hydrocarbon fuel mixture F1 is preheated with air and then condensed to remove water; 2 The CO obtained from the oxidation reactor R2 is used to preheat the carbon dioxide after condensation and dehydration; the high-temperature oxygen-depleted gas F5 from the air reactor R3 is used to preheat the fresh air F2; all reactors are in adiabatic conditions, ensuring the effective use of heat. The third stage of the oxygen carrier reaction process is the complete oxidation of the oxygen carrier by air. A large amount of heat will be released during the reaction of oxygen and oxygen carrier, which will increase the bed temperature of the oxygen carrier and absorbent, and at the same time, high-temperature tail gas will be discharged. This heat is transferred to the absorbent regeneration reactor through heat conduction to regenerate the absorbent, without the need for additional heat supply, thus achieving the self-heating balance of the system.

[0098] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A chemical chain conversion system for hydrocarbon fuels containing high concentration CO2, characterized in that: include: Fuel reactor, CO2 oxidation reactor, absorbent regeneration reactor and air reactor; The fuel reactor is respectively provided with an oxygen carrier inlet, an absorbent inlet and a fuel inlet for introducing a high-concentration CO2 hydrocarbon fuel mixture. The first outlet of the fuel reactor is connected to the inlet of a separation device, and the first discharge port of the separation device is connected to the first inlet of the CO2 oxidation reactor, so as to introduce the reduced oxygen carrier to be reduced into the CO2 oxidation reactor. The second discharge port of the separation device is connected to the inlet of the absorbent regeneration reactor, so as to introduce the absorbent after absorbing CO2 into the absorbent regeneration reactor. The first outlet of the absorbent regeneration reactor is connected to the absorbent inlet of the fuel reactor through a riser, and the second outlet of the absorbent regeneration reactor is connected to the second inlet of the CO2 oxidation reactor for introducing the desorbed CO2 into the CO2 oxidation reactor; The first outlet of the CO2 oxidation reactor is connected to the first inlet of the air reactor for introducing the partially oxidized oxygen carrier into the air reactor, and the second outlet of the CO2 oxidation reactor is used for outputting the product CO; Air is introduced into the second inlet of the air reactor, and the outlet of the air reactor is connected to the oxygen carrier inlet of the fuel reactor through the lifting pipe; a heat conduction device is arranged between the air reactor and the absorbent regeneration reactor for conducting the reaction heat generated in the air reactor to the absorbent regeneration reactor.

2. The chemical chain conversion system for hydrocarbon fuels containing high concentration of CO2 according to claim 1, characterized in that: It also includes a CO purification system, the inlet of the CO purification system is connected to the second outlet of the CO2 oxidation reactor, and is used to separate the CO2 mixed in the product CO. The first outlet of the CO purification system is connected to the third inlet of the CO2 oxidation reactor, and is used to introduce the separated CO2 into the CO2 oxidation reactor. The second outlet of the CO purification system is used to output the purified final product CO.

3. The chemical chain conversion system for hydrocarbon fuels containing high concentration of CO2 according to claim 2, characterized in that: The CO purification system adopts a pressure swing adsorption device.

4. The chemical chain conversion system for hydrocarbon fuels containing high concentration of CO2 according to claim 1, characterized in that: It also includes a gas-liquid separator, the inlet of which is connected to the second outlet of the fuel reactor, and is used to introduce the water vapor generated in the fuel reactor into the gas-liquid separator. The first outlet of the gas-liquid separator is connected to the fourth inlet of the CO2 oxidation reactor, and is used to separate the CO2 mixed in the water vapor and introduce it into the CO2 oxidation reactor. The second outlet of the gas-liquid separator is used to discharge the separated water.

5. The chemical chain conversion system for hydrocarbon fuels containing high concentration CO2 according to claim 1, characterized in that: The fuel inlet of the fuel reactor is arranged at the bottom of the fuel reactor, the oxygen carrier inlet is arranged at the top of the fuel reactor, and the absorbent inlet is arranged in the middle of the fuel reactor.

6. The chemical chain conversion system for hydrocarbon fuels containing high concentration of CO2 according to claim 1, characterized in that: The oxygen carrier is an iron-based oxygen carrier, a bimetallic / multimetallic oxygen carrier, or a perovskite oxygen carrier.

7. The chemical chain conversion system for hydrocarbon fuels containing high concentration CO2 according to claim 1, characterized in that: The absorbent is solid CO2 absorbent particles, including active absorption medium, which is any one of CaO, Li4SiO4, and hydrotalcite.

8. The chemical chain conversion system for hydrocarbon fuels containing high concentration CO2 according to claim 4, characterized in that: It also includes a preheater, which is respectively arranged at the fuel inlet of the fuel reactor, the fourth inlet of the CO2 oxidation reactor and the second inlet of the air reactor.

9. A fuel conversion method for a hydrocarbon fuel chemical chain conversion system containing high concentration CO2 as claimed in any one of claims 1 to 8, characterized in that: include: A high-concentration CO2 hydrocarbon fuel is fed through the fuel inlet of the fuel reactor, an oxygen carrier is fed through the oxygen carrier inlet of the fuel reactor, and an absorbent is fed through the absorbent inlet of the fuel reactor, so that the hydrocarbon fuel mixture and the oxygen carrier undergo a complete oxidation reaction in the fuel reactor to produce a reduced oxygen carrier, carbon dioxide and water, and at the same time, the carbon dioxide in the fuel reactor is absorbed by the absorbent; The absorbent after absorbing carbon dioxide enters the absorbent regeneration reactor to undergo a desorption reaction, and the generated carbon dioxide enters the CO2 oxidation reactor through the second inlet of the CO2 oxidation reactor. The desorbed absorbent re-enters the fuel reactor through the absorbent inlet of the fuel reactor to participate in the next cycle; The reduced oxygen carrier enters the CO2 oxidation reactor and reacts with the carbon dioxide in the CO2 oxidation reactor to produce carbon monoxide and partially oxidized oxygen carrier; The partially oxidized oxygen carrier enters the air reactor, is further oxidized by the air in the air reactor to increase its temperature, and re-enters the fuel reactor through the oxygen carrier inlet of the fuel reactor to participate in the next cycle; the heat generated in the air reactor is transferred to the absorbent regeneration reactor through a heat conduction device.

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