System device and method for adsorbing, desorbing and recycling carbon dioxide in high-temperature flue gas and performing one-step hydrogenation resource utilization on carbon dioxide

Abstract

The invention discloses a system device for adsorbing, desorbing and recycling carbon dioxide in high-temperature flue gas and performing one-step hydrogenation resource utilization. The system device comprises a waste heat recycling unit, a pretreatment unit, a carbon dioxide recycling unit, a hydrogenation reaction unit and a separation and purification unit, the waste heat recovery unit comprises a first heat exchanger, a rectification reboiler and a second heat exchanger; the pretreatment unit comprises a denitration reactor, a dust remover, supergravity desulfurization equipment and the like; the carbon dioxide recovery unit comprises a carbon dioxide adsorption bed and a regeneration device; the hydrogenation reaction unit comprises a gas mixer, a third heat exchanger and a hydrogenation reactor; the separation and purification unit comprises a fourth heat exchanger, a gas-liquid separator, a feeding pump, a fifth heat exchanger and a rectification separation device. Through carbon dioxide adsorption and hot hydrogen gas stripping desorption, effective recovery of flue gas carbon dioxide is achieved, and the device has the advantages of being simple and high in energy efficiency; as the high-temperature flue gas waste heat recovery process and the carbon dioxide resource utilization process are coupled, heat integration in the system is achieved, and energy conservation and consumption reduction are achieved.

Description

Technical Field

[0001] The present invention relates to a high-temperature flue gas carbon dioxide recovery and resource utilization process and application field. More specifically, it relates to a high-temperature flue gas carbon dioxide recovery by adsorption and desorption and a one-step hydrogenation resource utilization system device and method. Background Art

[0003] Methanol and methane are ideal hydrogen storage media and important bulk basic chemical raw materials. For example, Chinese patent ZL201210121972.7 discloses a process and equipment for converting carbon dioxide in flue gas into natural gas using excess electricity. The process first uses excess electricity to electrolyze water to produce hydrogen, then the hydrogen reacts with carbon dioxide captured from industrial flue gas to undergo a methanogenic reaction, and at the same time uses the heat generated by the methanogenic reaction to heat water to produce superheated steam, drive a steam turbine generator to generate electricity, and supplement the electricity from the electrolysis of water, thereby synthesizing natural gas that can be easily stored or transported.

[0004] For another example, Chinese patent ZL201610276360.3 discloses a device and method for converting carbon dioxide in high-temperature flue gas from electrolytic aluminum into methanol. The method passes the high-temperature flue gas from electrolytic aluminum into a gas converter filled with coke to convert carbon dioxide in the flue gas into carbon monoxide. The flue gas discharged from the gas converter is defluorinated and dust-removed, and then mixed with hydrogen produced as a by-product of the chlor-alkali process to obtain synthesis gas. The synthesis gas is passed into a gas purification device to deeply remove sulfur, chlorine and fluorine therein, and then the synthesis gas is compressed to 8 to 15 MPa to prepare methanol in a methanol synthesis tower.

[0005] For example, Chinese patent ZL201910234831.8 discloses a combined system and method for converter flue gas treatment and methanol preparation. The system includes flue gas pretreatment equipment, crude methanol preparation equipment and methanol refining equipment; the flue gas pretreatment equipment includes a converter hood, a vaporization and cooling flue and a valve with a flue gas component detector; the crude methanol preparation equipment includes a carbonization reactor and a shell-and-tube low-pressure isothermal reaction synthesizer; the flue gas is released from the converter and collected by the converter hood, and after being cooled by the vaporization and cooling flue, it enters the valve with a flue gas component detector. When the valve with the flue gas component detector detects that the CO volume fraction in the flue gas is less than 40%, the valve guides the flue gas into the carbonization reactor and the shell-and-tube low-pressure isothermal reaction synthesizer for crude methanol preparation.

[0006] The above-mentioned prior arts have solved their respective technical problems, but the above-mentioned prior arts still have the following defects: 1) the waste heat of high-temperature flue gas is not effectively recovered or most of it is used for recovery and power generation, and the energy conversion efficiency is low; 2) the process of resource-based hydrogenation to produce methanol requires the high-temperature flue gas to pass through a gas reformer to convert carbon dioxide into carbon monoxide and then hydrogenate to synthesize methanol, which requires the introduction of high-calorific value fuels such as coke or charcoal and increases equipment and energy consumption investment. Therefore, it is of great practical significance and industrial application value to develop a system process for efficient resource utilization of high-temperature flue gas carbon dioxide hydrogenation to solve the problems of flue gas waste heat recovery and carbon dioxide resource utilization. Summary of the invention

[0007] The first technical problem to be solved by the present invention is to provide a system device for the recovery of high-temperature flue gas carbon dioxide by absorption and desorption and its one-step hydrogenation resource utilization. The system device couples the recovery of high-temperature flue gas waste heat and the resource utilization of carbon dioxide, realizing the heat integration within the system device; in addition, through carbon dioxide adsorption and hot hydrogen gas stripping and desorption, the flue gas carbon dioxide is effectively recovered, with the advantages of simple device and high energy efficiency.

[0008] The second technical problem to be solved by the present invention is to provide a method for resource utilization of high-temperature flue gas carbon dioxide hydrogenation using the above-mentioned system device.

[0009] To solve the above-mentioned first technical problem, the technical solution adopted by the present invention is as follows :

[0010] A system device for recovering carbon dioxide from high-temperature flue gas by adsorption and desorption and its one-step hydrogenation resource utilization, comprising a waste heat recovery unit, a pretreatment unit, a carbon dioxide recovery unit, a hydrogenation reaction unit and a separation and purification unit;

[0011] The waste heat recovery unit includes a first heat exchanger, a rectification reboiler, and a second heat exchanger;

[0012] The pretreatment unit includes a denitration reactor, a dust collector, a supergravity desulfurization device, etc.;

[0013] The carbon dioxide recovery unit includes a carbon dioxide adsorption bed and a regeneration device;

[0014] The hydrogenation reaction unit comprises a gas mixer, a third heat exchanger and a hydrogenation reactor;

[0015] The separation and purification unit comprises a fourth heat exchanger, a gas-liquid separator, a rectification feed pump, a fifth heat exchanger and a rectification separation device;

[0016] The transverse heat exchange outlet of the first heat exchanger is connected to the distillation reboiler through a pipeline; the material outlet of the distillation reboiler is connected to the second heat exchanger through a pipeline; the outlet of the second heat exchanger is connected to the parallel carbon dioxide adsorption bed and the regeneration device through two pipelines respectively; the outlets of the carbon dioxide adsorption bed and the regeneration device are connected to the external environment through the exhaust gas pipeline;

[0017] The outlets of the carbon dioxide adsorption bed and the regeneration device are provided with branch pipelines connected to a gas mixer;

[0018] The outlet of the gas mixer leads to the longitudinal heat exchange inlet of the third heat exchanger, the longitudinal heat exchange outlet of the third heat exchanger leads to the hydrogenation reactor, the lower material outlet of the hydrogenation reactor leads to the transverse heat exchange inlet of the third heat exchanger, the transverse heat exchange outlet of the third heat exchanger leads to the fourth heat exchanger through a pipeline, and the outlet of the fourth heat exchanger leads to the gas-liquid separator through a pipeline;

[0019] The lower part of the gas-liquid separator is connected to the inlet of the distillation feed pump through a pipeline, the outlet of the distillation feed pump is connected to the longitudinal heat exchange inlet of the fifth heat exchanger through a pipeline, and the longitudinal heat exchange outlet of the fifth heat exchanger is connected to the distillation separation equipment through a pipeline; the upper part of the gas-liquid separator is connected to the compressor through a pipeline, and the compressor outlet is connected to the gas mixer through a pipeline; the upper part of the gas-liquid separator is also connected to the external exhaust gas pipeline and the product pipeline through a pipeline;

[0020] The lower part of the rectification and separation equipment is connected to the rectification reboiler through a pipeline for heat exchange and then circulated back to the rectification and separation equipment;

[0021] The upper portion of the rectification and separation equipment is connected to an external product pipeline via a pipeline.

[0022] Preferably, the carbon dioxide adsorption beds are provided with 2 to 20; more preferably, the number of the adsorption beds is 2 to 5; adsorption and gas stripping and desorption are performed alternately in each adsorption bed to ensure continuous operation of the system.

[0023] To solve the above second technical problem, the present invention adopts the following technical solution :

[0024] A method for realizing resource utilization of high-temperature flue gas carbon dioxide hydrogenation using the above system device comprises the following steps:

[0025] S1. The high-temperature flue gas containing carbon dioxide heats the raw hydrogen and the bottom material of the distillation reboiler through the first heat exchanger and the second heat exchanger in turn, so as to recover the waste heat of the flue gas and obtain low-temperature flue gas;

[0026] S2. The low-temperature flue gas is further passed through a pretreatment unit to remove nitrogen oxides, flue gas, and sulfur oxides from the flue gas;

[0027] S3, the pretreated flue gas enters the carbon dioxide adsorption bed and the regeneration device to achieve the adsorption of carbon dioxide. After reaching the adsorption saturation, the heated raw hydrogen is introduced to perform gas stripping and desorption of carbon dioxide to form a mixed gas of hydrogen and carbon dioxide; the carbon dioxide adsorption bed and the regeneration device alternately perform adsorption and gas stripping and desorption;

[0028] S4, the mixed gas of hydrogen and carbon dioxide enters the hydrogenation reactor after heat exchange with the material at the outlet of the hydrogenation reactor, and performs carbon dioxide hydrogenation reaction to produce methanol or methane;

[0029] S5. If a methanol production reaction is carried out, the material after the reaction is first cooled and then passed through a gas-liquid separator for gas-liquid separation. The unreacted raw materials are separated and circulated to the inlet of the hydrogenation reactor through a compressor. The liquid-phase material enters the distillation separation equipment, and the methanol product is obtained at the top of the distillation separation equipment. If a methane production reaction is carried out, the material after the reaction is first cooled and then passed through a gas-liquid separator for gas-liquid separation. The gas-phase material at the top is the methane product.

[0030] Preferably, in step S1, the high-temperature flue gas comes from one of combustion flue gas, smelting flash furnace flue gas, converter flue gas, calcium carbide furnace flue gas and glass kiln flue gas.

[0031] Preferably, in step S3, the raw hydrogen comes from one or more of coal-based hydrogen production, natural gas-based hydrogen production, water electrolysis hydrogen production and industrial by-product hydrogen production devices; more preferably, the raw hydrogen comes from water electrolysis hydrogen production.

[0032] Preferably, in step S3, the adsorption material filled in the carbon dioxide adsorption bed is one or more of activated alumina, molecular sieve and activated carbon.

[0033] Preferably, in step S3, the temperature in the carbon dioxide adsorption bed is 20-400° C., and the pressure is 0.1-5 MPa.

[0034] Preferably, in step S4, the hydrogenation reactor is a fixed bed reactor or a supergravity reactor, and the catalyst loaded therein is one of Cu-based, Ni-based, Au-based and Ag-based catalysts.

[0035] Preferably, in step S4, the reaction temperature in the hydrogenation reactor is 100-500° C., more preferably, 200-300° C.; the pressure is 0.1-10 MPa, more preferably, the pressure is 0.1-5 MPa.

[0036] Preferably, in step S5, the distillation separation equipment is an ultra-gravity distillation separation equipment.

[0037] Any range described in the present invention includes the end value and any numerical value between the end values ​​and any sub-range formed by the end value or any numerical value between the end values.

[0038] Unless otherwise specified, all raw materials in the present invention can be purchased from the market, and the equipment used in the present invention can adopt conventional equipment in the relevant field or refer to the existing technology in the relevant field.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The system device of the present invention for adsorption and desorption recovery of high-temperature flue gas carbon dioxide and one-step hydrogenation resource utilization couples the waste heat recovery of high-temperature flue gas, the adsorption recovery and resource utilization of carbon dioxide in the flue gas, realizes the effective integrated utilization of heat in the system, and provides a powerful way to achieve the "dual carbon" goal.

[0041] 2. The present invention realizes the recovery of flue gas carbon dioxide by means of carbon dioxide adsorption and hot hydrogen gas stripping desorption, without the need to introduce other gases outside the system for desorption and separation. It has the advantages of simple device, easy operation, little impact on the environment and high energy efficiency.

[0042] 3. The system and method for recovery of high-temperature flue gas carbon dioxide by adsorption and desorption and its one-step hydrogenation resource utilization provided by the present invention can flexibly produce methanol or methane according to market demand. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0044] Figure 1 The schematic diagram of the system device structure of the present invention for the adsorption and desorption recovery of high-temperature flue gas carbon dioxide and its one-step hydrogenation resource utilization is shown. DETAILED DESCRIPTION

[0045] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments. It should be understood by those skilled in the art that the following specific description is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0046] join Figure 1 As shown, as one aspect of the present invention, a system device for recovering carbon dioxide from high-temperature flue gas by adsorption and desorption and one-step hydrogenation for resource utilization of the system device comprises a waste heat recovery unit, a pretreatment unit, a carbon dioxide recovery unit, a hydrogenation reaction unit and a separation and purification unit;

[0047] The waste heat recovery unit is used to recover the heat in the high-temperature flue gas to supply energy to other devices in the system, so as to realize the effective integrated utilization of the heat in the system, and includes a first heat exchanger 3, which is used to heat the raw hydrogen gas with the high-temperature flue gas and then recover the carbon dioxide by gas stripping; a distillation reboiler 14, which is used to realize the vaporization of the bottom material of the distillation equipment by heating with the high-temperature flue gas; and a second heat exchanger 15, which is used to provide heat to the public works in the system;

[0048] The pretreatment unit is used to remove nitrogen oxides, smoke particles and sulfur oxides in the flue gas, which is beneficial to the subsequent recovery of carbon dioxide in the flue gas;

[0049] The carbon dioxide recovery unit is used for recovering carbon dioxide from flue gas, and comprises a carbon dioxide adsorption bed 4-1 and a regeneration device 4-2. The carbon dioxide in flue gas is adsorbed by the adsorption bed. After adsorption is saturated, the carbon dioxide is stripped and desorbed by heating with hot hydrogen and reducing the partial pressure of carbon dioxide on the adsorbent, thereby recovering and enriching carbon dioxide.

[0050] The hydrogenation reaction unit comprises a gas mixer 5, a third heat exchanger 6 and a hydrogenation reactor 8, and the hydrogenation reaction unit is used for performing a carbon dioxide hydrogenation reaction;

[0051] The separation and purification unit comprises a fourth heat exchanger 9, a gas-liquid separator 10, the gas-liquid separator 10 is used to separate the gas and liquid phases in the product, a distillation feed pump 11, a fifth heat exchanger 12 and a distillation separation device 13, the distillation separation device 13 is used to further separate different components in the liquid phase;

[0052] The transverse heat exchange outlet of the first heat exchanger 3 is connected to the distillation reboiler 14 through a pipeline; the material outlet of the distillation reboiler 14 is connected to the second heat exchanger 15 through a pipeline; the outlet of the second heat exchanger 15 is connected to the parallel carbon dioxide adsorption bed 4-1 and the regeneration device 4-2 through two pipelines respectively; the outlets of the carbon dioxide adsorption bed 4-1 and the regeneration device 4-2 are connected to the external environment through the exhaust gas pipeline; it can be understood that the regeneration device 4-2 is also a carbon dioxide adsorption bed, and adsorption and gas stripping and desorption are alternately performed in each adsorption bed to ensure the continuous operation of the system. For the convenience of understanding, it is named as an adsorption bed in the adsorption process and a regeneration device in the gas stripping and desorption process;

[0053] The outlets of the carbon dioxide adsorption bed 4-1 and the regeneration device 4-2 are provided with branch pipes connected to the gas mixer 5;

[0054] The outlet of the gas mixer 5 leads to the longitudinal heat exchange inlet of the third heat exchanger 6, the longitudinal heat exchange outlet of the third heat exchanger 6 leads to the hydrogenation reactor 8, the lower material outlet of the hydrogenation reactor 8 leads to the transverse heat exchange inlet of the third heat exchanger 6, the transverse heat exchange outlet of the third heat exchanger 6 leads to the fourth heat exchanger 9 through a pipeline, and the outlet of the fourth heat exchanger 9 leads to the gas-liquid separator 5 through a pipeline;

[0055] The lower part of the gas-liquid separator is connected to the inlet of the distillation feed pump through a pipeline, the outlet of the distillation feed pump is connected to the longitudinal heat exchange inlet of the fifth heat exchanger through a pipeline, and the longitudinal heat exchange outlet of the fifth heat exchanger is connected to the distillation separation equipment through a pipeline; the upper part of the gas-liquid separator is connected to the compressor through a pipeline, and the compressor outlet is connected to the gas mixer through a pipeline; the upper part of the gas-liquid separator is also connected to the external exhaust gas pipeline and the product pipeline through a pipeline;

[0056] The lower part of the rectification and separation equipment is connected to the rectification reboiler through a pipeline for heat exchange and then circulated back to the rectification and separation equipment;

[0057] The upper portion of the rectification and separation equipment is connected to an external product pipeline via a pipeline.

[0058] Preferably, the carbon dioxide adsorption beds are provided with 2 to 20; more preferably, the number of the adsorption beds is 2 to 5, because too many adsorption beds will increase the corresponding equipment and other investment costs; adsorption and gas stripping and desorption are carried out alternately in each adsorption bed to ensure continuous operation of the system.

[0059] As another aspect of the present invention, a method for realizing resource utilization of high-temperature flue gas carbon dioxide hydrogenation by using the above-mentioned system device comprises the following steps:

[0060] S1, the high-temperature flue gas containing carbon dioxide passes through the first heat exchanger 3 and the second heat exchanger 15 to heat the raw hydrogen and the bottom material of the distillation reboiler 14, so as to recover the waste heat of the flue gas and obtain low-temperature flue gas;

[0061] S2, the low-temperature flue gas further passes through the pretreatment unit 16 to remove nitrogen oxides, flue gas, and sulfur oxides in the flue gas;

[0062] S3, the pretreated flue gas enters the carbon dioxide adsorption bed 4-1 and the regeneration device 4-2 to achieve adsorption of carbon dioxide. After reaching adsorption saturation, the heated raw hydrogen is introduced to perform gas stripping and desorption of carbon dioxide to form a mixed gas of hydrogen and carbon dioxide; the carbon dioxide adsorption bed and the regeneration device alternately perform adsorption and gas stripping and desorption;

[0063] S4, the mixed gas of hydrogen and carbon dioxide enters the hydrogenation reactor 8 after heat exchange with the material at the outlet of the hydrogenation reactor 8, and undergoes carbon dioxide hydrogenation reaction to produce methanol or methane;

[0064] S5. If a methanol production reaction is carried out, the material after the reaction is first cooled and then passed through a gas-liquid separator 10 for gas-liquid separation. The unreacted raw materials are separated and circulated to the inlet of the hydrogenation reactor 8 through a compressor 7. The liquid-phase material enters the distillation separation equipment 13, and a methanol product is obtained at the top of the distillation separation equipment 13. If a methane production reaction is carried out, the material after the reaction is first cooled and then passed through a gas-liquid separator 10 for gas-liquid separation. The gas-phase material at the top is a methane product.

[0065] According to some embodiments of the present invention, in step S1, the high-temperature flue gas comes from one of combustion flue gas, smelting flash furnace flue gas, converter flue gas, calcium carbide furnace flue gas, and glass kiln flue gas.

[0066] According to certain embodiments of the present invention, in step S1, the raw hydrogen comes from one or more of coal-based hydrogen production, natural gas-based hydrogen production, water electrolysis hydrogen production, and industrial by-product hydrogen production devices; more preferably, the raw hydrogen comes from water electrolysis hydrogen production.

[0067] According to some embodiments of the present invention, in step S3, the adsorption material loaded in the carbon dioxide adsorption bed is one or more of activated alumina, molecular sieve and activated carbon.

[0068] According to some embodiments of the present invention, in step S3, the temperature in the carbon dioxide adsorption bed is 20-400° C., and the pressure is 0.1-5 MPa.

[0069] According to certain embodiments of the present invention, in step S4, the hydrogenation reactor is a fixed bed reactor or a supergravity reactor, and the catalyst loaded therein is one of Cu-based, Ni-based, Au-based, and Ag-based catalysts.

[0070] According to certain embodiments of the present invention, in step S4, the reaction temperature in the hydrogenation reactor is 100-500°C, more preferably 200-300°C; the pressure is 0.1-10MPa, more preferably 0.1-5MPa. Because too high a temperature will lead to a decrease in the equilibrium conversion rate of the exothermic reaction and a decrease in the selectivity of methanol, etc., but too low a temperature will lead to a decrease in the reaction rate, so there is an optimal reaction temperature range for this process. Too high a pressure will increase the investment and operating costs of the device.

[0071] According to some embodiments of the present invention, in step S5, the distillation separation equipment is a high-gravity distillation separation equipment, because the high-gravity distillation separation equipment can reduce energy consumption and equipment size, which is conducive to improving intrinsic safety.

[0072] Example 1

[0073] Use Figure 1The system device for recovering high-temperature flue gas carbon dioxide by absorption and desorption and its one-step hydrogenation resource utilization is shown to produce methanol, including the following steps:

[0074] S1, 500℃ high temperature flue gas (containing 15vol.%CO 2 , 80vol.%N 2 , 4.5 vol.% O 2 , 0.07 vol.% SO 2 ,400mg / Nm 3 NOx and other substances such as dust) are heated to 200℃ by heat exchangers, and the distillation tower bottom liquid and public works are heated to recover the flue gas waste heat to obtain low-temperature flue gas with a temperature of 50℃;

[0075] S2, low-temperature flue gas enters the pretreatment unit to remove nitrogen oxides, flue gas, and sulfur oxides in the flue gas to meet the emission standards;

[0076] S3. The pretreated flue gas enters the carbon dioxide adsorption bed and regeneration device, which are equipped with molecular sieves. The pressure in the adsorption bed and regeneration device is controlled at 0.5MPa and the temperature is controlled at 30°C to achieve adsorption of carbon dioxide. After reaching adsorption saturation, heated raw hydrogen is introduced to perform gas stripping and desorption of carbon dioxide to form a mixed gas of hydrogen and carbon dioxide; the carbon dioxide adsorption bed and regeneration device perform adsorption and gas stripping and desorption alternately;

[0077] S4, the mixed gas of hydrogen and carbon dioxide, after heat exchange with the material at the outlet of the hydrogenation reactor, enters the Cu / ZnO / Al 2 O 3 A reaction of carbon dioxide and hydrogen to produce methanol occurs in a fixed-bed hydrogenation reactor of the catalyst, and the reaction temperature in the reactor is controlled to be 250°C and the reaction pressure is 5MPa;

[0078] S5. The reacted material is first cooled and then passed through a gas-liquid separation tank for gas-liquid separation. The unreacted raw materials are separated and circulated to the reactor inlet. The liquid phase material enters the methanol distillation tower, and the methanol product is obtained at the top of the distillation tower.

[0079] Example 2

[0080] Use Figure 1 The system device for recovering high-temperature flue gas carbon dioxide by absorption and desorption and its one-step hydrogenation resource utilization is shown to produce methanol, including the following steps:

[0081] S1, 500℃ high temperature flue gas (containing 15vol.%CO 2 , 80vol.%N 2, 4.5 vol.% O 2 , 0.07 vol.% SO 2 ,400mg / Nm 3 NOx and other substances such as dust) are heated to 200℃ by heat exchangers, and the distillation tower bottom liquid and public works are heated to recover the flue gas waste heat to obtain low-temperature flue gas with a temperature of 50℃;

[0082] S2, low-temperature flue gas enters the pretreatment unit to remove nitrogen oxides, flue gas, and sulfur oxides in the flue gas to meet the emission standards;

[0083] S3. The pretreated flue gas enters the carbon dioxide adsorption bed and regeneration device, which are filled with activated carbon. The pressure in the adsorption bed and regeneration device is controlled at 0.5MPa and the temperature is controlled at 30°C to achieve the adsorption of carbon dioxide. After the adsorption is saturated, the heated raw hydrogen is introduced to perform gas stripping and desorption of carbon dioxide to form a mixed gas of hydrogen and carbon dioxide. The carbon dioxide adsorption bed and regeneration device perform adsorption and gas stripping and desorption alternately.

[0084] S4, after heat exchange with the outlet material of the hydrogenation reactor, the mixed gas of hydrogen and carbon dioxide enters the fixed bed hydrogenation reactor filled with Au / ZnO catalyst to react with carbon dioxide and hydrogen to generate methanol, and the reaction temperature in the reactor is controlled to be 250°C and the reaction pressure is 5MPa;

[0085] S5. The reacted material is first cooled and then passed through a gas-liquid separation tank for gas-liquid separation. The unreacted raw materials are separated and circulated to the reactor inlet. The liquid phase material enters the methanol distillation tower, and the methanol product is obtained at the top of the distillation tower.

[0086] Example 3

[0087] Use Figure 1 The system device for recovering high-temperature flue gas carbon dioxide by absorption and desorption and its one-step hydrogenation resource utilization is shown to produce methanol, including the following steps:

[0088] S1, 500℃ high temperature flue gas (containing 15vol.%CO 2 , 80vol.%N 2 , 4.5 vol.% O 2 , 0.07 vol.% SO 2 ,400mg / Nm 3 NOx and other substances such as dust) are heated to 200℃ by heat exchangers, and the distillation tower bottom liquid and public works are heated to recover the flue gas waste heat to obtain low-temperature flue gas with a temperature of 50℃;

[0089] S2, low-temperature flue gas enters the pretreatment unit to remove nitrogen oxides, flue gas, and sulfur oxides in the flue gas to meet the emission standards;

[0090] S3. The pretreated flue gas enters the carbon dioxide adsorption bed and regeneration device, which are filled with activated alumina. The pressure in the adsorption bed and regeneration device is controlled at 0.5MPa and the temperature is controlled at 30°C to achieve adsorption of carbon dioxide. After reaching adsorption saturation, heated raw hydrogen is introduced to perform gas stripping and desorption of carbon dioxide to form a mixed gas of hydrogen and carbon dioxide. The carbon dioxide adsorption bed and regeneration device perform adsorption and gas stripping and desorption alternately.

[0091] S4, the mixed gas of hydrogen and carbon dioxide, after heat exchange with the outlet material of the hydrogenation reactor, enters the Ag / ZrO 2 A reaction of carbon dioxide and hydrogen to produce methanol occurs in a fixed-bed hydrogenation reactor of the catalyst, and the reaction temperature in the reactor is controlled to be 250°C and the reaction pressure is 5MPa;

[0092] S5. The reacted material is first cooled and then passed through a gas-liquid separation tank for gas-liquid separation. The unreacted raw materials are separated and circulated to the reactor inlet. The liquid phase material enters the methanol distillation tower, and the methanol product is obtained at the top of the distillation tower.

[0093] Example 4

[0094] Use Figure 1 The system device for recovering high-temperature flue gas carbon dioxide by absorption and desorption and its one-step hydrogenation resource utilization is shown, and the reaction of producing methane includes the following steps:

[0095] S1, 500℃ high temperature flue gas (containing 15vol.%CO 2 , 80vol.%N 2 , 4.5 vol.% O 2 , 0.07 vol.% SO 2 ,400mg / Nm 3 NOx and other substances such as dust) are heated to 200℃ by the heat exchanger, and then the system utilities are heated to recover the flue gas waste heat to obtain low-temperature flue gas with a temperature reduced to 50℃;

[0096] S2. The low-temperature flue gas then further passes through the pretreatment unit to remove nitrogen oxides, flue gas, and sulfur oxides in the flue gas until it reaches the emission standard;

[0097] S3. The pretreated flue gas enters the adsorption bed, which is equipped with a molecular sieve. The pressure in the adsorption bed and the regeneration device is controlled at 0.5MPa and the temperature is controlled at 30°C to achieve the adsorption of carbon dioxide. After reaching adsorption saturation, the heated raw hydrogen is introduced to perform gas stripping and desorption of carbon dioxide to form a mixed gas of hydrogen and carbon dioxide; the carbon dioxide adsorption bed and the regeneration device perform adsorption and gas stripping and desorption alternately;

[0098] S4, the mixed gas of hydrogen and carbon dioxide, after heat exchange with the material at the outlet of the hydrogenation reactor, enters the NiMn / Al 2 O 3 In the fixed bed hydrogenation reactor of the catalyst, carbon dioxide hydrogenation reaction occurs to produce methane, and the reaction temperature in the reactor is controlled to be 300°C and the reaction pressure is 2MPa;

[0099] S5. The reacted material is first cooled and then passed through a gas-liquid separator for gas-liquid separation. The top gas phase material is a qualified methane product.

[0100] Comparative Example 1

[0101] Example 1 was repeated, except that a monoethanolamine double tower absorption and desorption decarbonization process was used instead of an adsorption bed to recover CO. 2 .

[0102] The results show that: to achieve the same effect, the investment cost of carbon dioxide recovery equipment will increase by 10%, and the annual operating investment cost of the entire system will increase by 32%.

[0103] Comparative Example 2

[0104] Example 1 was repeated, except that a multi-stage heat transfer high gravity reactor was used instead of a fixed bed reactor for CO 2 Methanol is produced by hydrogenation reaction.

[0105] The results showed that: when achieving the same methanol production, the system using the ultra-gravity reactor had a 13% shorter operating time than the system using the fixed bed reactor; in addition, it was found that the investment cost of the reactor equipment would be reduced by 22% and the annual operating investment cost would be reduced by 16%.

[0106] Comparative Example 3

[0107] Example 1 was repeated, except that the reaction temperature in the fixed bed hydrogenation reactor was controlled at 400°C.

[0108] The results showed that the selectivity of methanol product decreased by more than 85%, and the selectivity of carbon monoxide increased significantly, which was not conducive to the formation of products.

[0109] Comparative Example 4

[0110] Example 1 was repeated, except that the pressure in the adsorption bed and the regeneration device was controlled at 0.1 MPa and the temperature was controlled at 80°C.

[0111] The results showed that the flue gas carbon dioxide recovery rate was reduced by 75%, which was not conducive to flue gas recovery and subsequent resource utilization.

[0112] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all implementation methods here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A system device for recovering high-temperature flue gas carbon dioxide by absorption and desorption and its one-step hydrogenation resource utilization, characterized in that: It includes a waste heat recovery unit, a pretreatment unit, a carbon dioxide recovery unit, a hydrogenation reaction unit and a separation and purification unit; The waste heat recovery unit includes a first heat exchanger, a rectification reboiler, and a second heat exchanger; The pretreatment unit includes a denitration reactor, a dust collector, a supergravity desulfurization device, etc.; The carbon dioxide recovery unit includes a carbon dioxide adsorption bed and a regeneration device; The hydrogenation reaction unit comprises a gas mixer, a third heat exchanger and a hydrogenation reactor; The separation and purification unit comprises a fourth heat exchanger, a gas-liquid separator, a rectification feed pump, a fifth heat exchanger and a rectification separation device; The transverse heat exchange outlet of the first heat exchanger is connected to the distillation reboiler through a pipeline; the material outlet of the distillation reboiler is connected to the second heat exchanger through a pipeline; the outlet of the second heat exchanger is connected to the parallel carbon dioxide adsorption bed and the regeneration device through two pipelines respectively; the outlets of the carbon dioxide adsorption bed and the regeneration device are connected to the external environment through the exhaust gas pipeline; The outlets of the carbon dioxide adsorption bed and the regeneration device are provided with branch pipelines connected to a gas mixer; The outlet of the gas mixer leads to the longitudinal heat exchange inlet of the third heat exchanger, the longitudinal heat exchange outlet of the third heat exchanger leads to the hydrogenation reactor, the lower material outlet of the hydrogenation reactor leads to the transverse heat exchange inlet of the third heat exchanger, the transverse heat exchange outlet of the third heat exchanger leads to the fourth heat exchanger through a pipeline, and the outlet of the fourth heat exchanger leads to the gas-liquid separator through a pipeline; The lower part of the gas-liquid separator is connected to the inlet of the distillation feed pump through a pipeline, the outlet of the distillation feed pump is connected to the longitudinal heat exchange inlet of the fifth heat exchanger through a pipeline, and the longitudinal heat exchange outlet of the fifth heat exchanger is connected to the distillation separation equipment through a pipeline; the upper part of the gas-liquid separator is connected to the compressor through a pipeline, and the compressor outlet is connected to the gas mixer through a pipeline; the upper part of the gas-liquid separator is also connected to the external exhaust gas pipeline and the product pipeline through a pipeline; The lower part of the rectification and separation equipment is connected to the rectification reboiler through a pipeline for heat exchange and then circulated back to the rectification and separation equipment; The upper portion of the rectification and separation equipment is connected to an external product pipeline via a pipeline.

2. According to claim 1, the system device for recovering high-temperature flue gas carbon dioxide by absorption and desorption and its one-step hydrogenation resource utilization is characterized by: The number of the carbon dioxide adsorption beds is 2 to 20; more preferably, the number of the adsorption beds is 2 to 5.

3. A method for recovering high-temperature flue gas carbon dioxide by adsorption and desorption using any system device in claim 1 or 2 and its one-step hydrogenation resource utilization, comprising the following steps: S1. The high-temperature flue gas containing carbon dioxide heats the raw hydrogen and the bottom material of the distillation reboiler through the first heat exchanger and the second heat exchanger in turn, so as to recover the waste heat of the flue gas and obtain low-temperature flue gas; S2. The low-temperature flue gas is further passed through a pretreatment unit to remove nitrogen oxides, flue gas, and sulfur oxides from the flue gas; S3, the pretreated flue gas enters the carbon dioxide adsorption bed and the regeneration device to achieve the adsorption of carbon dioxide. After reaching the adsorption saturation, the heated raw hydrogen is introduced to perform gas stripping and desorption of carbon dioxide to form a mixed gas of hydrogen and carbon dioxide; the carbon dioxide adsorption bed and the regeneration device alternately perform adsorption and gas stripping and desorption; S4, the mixed gas of hydrogen and carbon dioxide enters the hydrogenation reactor after heat exchange with the material at the outlet of the hydrogenation reactor, and performs carbon dioxide hydrogenation reaction to produce methanol or methane; S5. If a methanol production reaction is carried out, the material after the reaction is first cooled and then passed through a gas-liquid separator for gas-liquid separation. The unreacted raw materials are separated and circulated to the inlet of the hydrogenation reactor through a compressor. The liquid-phase material enters the distillation separation equipment, and the methanol product is obtained at the top of the distillation separation equipment. If a methane production reaction is carried out, the material after the reaction is first cooled and then passed through a gas-liquid separator for gas-liquid separation. The gas-phase material at the top is the methane product.

4. The method for recovering high-temperature flue gas carbon dioxide by absorption and desorption and its one-step hydrogenation resource utilization according to claim 3 is characterized in that: In step S1, the high-temperature flue gas comes from one of combustion flue gas, smelting flash furnace flue gas, converter flue gas, calcium carbide furnace flue gas and glass kiln flue gas.

5. The method for recovering high-temperature flue gas carbon dioxide by absorption and desorption and its one-step hydrogenation resource utilization according to claim 3 is characterized in that: In step S1, the raw hydrogen comes from one or more of coal-based hydrogen production, natural gas-based hydrogen production, water electrolysis hydrogen production and industrial by-product hydrogen production devices; more preferably, the raw hydrogen comes from water electrolysis hydrogen production.

6. The method for recovering high-temperature flue gas carbon dioxide by absorption and desorption and its one-step hydrogenation resource utilization according to claim 3 is characterized in that: In step S3, the adsorption material filled in the carbon dioxide adsorption bed is one or more of activated alumina, molecular sieve and activated carbon.

7. The method for recovering high-temperature flue gas carbon dioxide by absorption and desorption and its one-step hydrogenation resource utilization according to claim 3, characterized in that: In step S3, the temperature in the carbon dioxide adsorption bed is 20-400° C., and the pressure is 0.1-5 MPa.

8. The method for recovering high-temperature flue gas carbon dioxide by absorption and desorption and its one-step hydrogenation resource utilization according to claim 3 is characterized in that: In step S4, the hydrogenation reactor is a fixed bed reactor or a supergravity reactor, and the catalyst loaded inside the fixed bed reactor is one of Cu-based, Ni-based, Au-based and Ag-based catalysts.

9. The method for recovering high-temperature flue gas carbon dioxide by absorption and desorption and its one-step hydrogenation resource utilization according to claim 3, characterized in that: In step S4, the reaction temperature in the hydrogenation reactor is 100-500° C., preferably 200-300° C.; the pressure is 0.1-10 MPa, preferably 0.1-5 MPa.

10. The method for recovering high-temperature flue gas carbon dioxide by absorption and desorption and its one-step hydrogenation resource utilization according to claim 3, characterized in that: In step S5, the distillation separation equipment is a super gravity distillation separation equipment.

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