阅读说明：本技术 一种富氧燃烧方法 (Oxygen-enriched combustion method ) 是由 周天宇 李玖重 孙志钦 张婧帆 高晓红 郜建松 王恒博 苏耀伦 于 2021-09-01 设计创作，主要内容包括：本发明公开了一种富氧燃烧方法,涉及有氧燃烧技术领域。一种富氧燃烧方法是利用吸氧单元、释氧单元和燃烧单元进行处理,包括：利用载氧体与含氧气体在吸氧单元进行反应得到富氧载氧体；富氧载氧体在高温烟气的作用下,在释氧单元释放出氧气,得到富氧气体和贫氧载氧体；利用富氧气体与燃料混合在燃烧单元进行燃烧。发明人创造性地将化学链制氧和有氧燃烧反应结合实现富氧燃烧,能够在不显著增加制氧成本的前提下,实现富氧燃烧,提高有氧燃烧的反应速率和热效率。由于助燃剂富氧气体中氮气含量很少,减少了氮气带走燃烧热量造成的热量损失,使燃烧后得到的烟气中主要成分为二氧化碳和水,便于二氧化碳的分离利用,并且减少了氮氧化物的产生。(The invention discloses an oxygen-enriched combustion method, and relates to the technical field of oxygen combustion. An oxygen-enriched combustion method is to utilize an oxygen absorption unit, an oxygen release unit and a combustion unit for processing, and comprises the following steps: reacting an oxygen carrier with oxygen-containing gas in an oxygen absorption unit to obtain an oxygen-enriched oxygen carrier; the oxygen-enriched oxygen carrier releases oxygen in the oxygen release unit under the action of high-temperature flue gas to obtain oxygen-enriched gas and an oxygen-poor oxygen carrier; the oxygen-enriched gas and the fuel are mixed and combusted in the combustion unit. The inventor creatively combines chemical chain oxygen generation and aerobic combustion reaction to realize oxygen-enriched combustion, can realize oxygen-enriched combustion on the premise of not remarkably increasing the oxygen generation cost, and improves the reaction rate and the thermal efficiency of the aerobic combustion. Because the content of nitrogen in the oxygen-enriched gas of the combustion improver is less, the heat loss caused by the combustion heat taken away by the nitrogen is reduced, the main components in the flue gas obtained after combustion are carbon dioxide and water, the separation and utilization of the carbon dioxide are convenient, and the generation of nitrogen oxides is reduced.)

1. An oxygen-enriched combustion method is characterized in that an oxygen absorption unit, an oxygen release unit and a combustion unit are used for processing, and the method comprises the following steps:

oxygen carrier and oxygen-containing gas are reacted in the oxygen absorption unit to obtain oxygen-enriched oxygen carrier, the oxygen-enriched oxygen carrier releases oxygen in the oxygen release unit under the action of high-temperature flue gas to obtain oxygen-enriched gas and oxygen-deficient oxygen carrier, and the oxygen-enriched gas and fuel are mixed in the combustion unit for combustion.

2. An oxygen-enriched combustion method as claimed in claim 1, wherein a part of the flue gas generated by the combustion unit is used as the high-temperature flue gas required by the oxygen release unit, another part of the high-temperature flue gas generated by the combustion unit is subjected to heat recovery by a flue gas heat exchange unit and then is subjected to separation by a flue gas separation unit to obtain water, carbon dioxide and waste gas, and the obtained carbon dioxide is conveyed to a carbon dioxide hydrogenation reaction unit for hydrogenation reaction;

the flue gas heat exchange unit exchanges heat between the high-temperature flue gas and the water obtained by the flue gas separation unit, recovers the heat of the high-temperature flue gas, and heats the water obtained by the flue gas separation unit to obtain water vapor.

3. An oxycombustion method according to claim 2, characterized in that the water vapor obtained from the flue gas heat exchange unit reacts with the oxygen-deficient oxygen carrier in a hydrogen production unit to produce a high temperature hydrogen-containing gas and a micro oxygen carrier, the micro oxygen carrier reacts with high temperature air in the oxygen absorption unit to obtain an oxygen-rich oxygen carrier and a high temperature oxygen-deficient air, and the high temperature hydrogen-containing gas is treated for the hydrogenation reaction.

4. An oxygen-enriched combustion method as claimed in claim 3, wherein the high-temperature hydrogen-containing gas is subjected to heat recovery and cooling by a hydrogen heat exchange unit, and then is subjected to treatment by a hydrogen separation unit to obtain water and low-temperature hydrogen, the water is conveyed to the flue gas heat exchange unit to exchange heat with the high-temperature flue gas, the low-temperature hydrogen and the high-temperature hydrogen-containing gas are subjected to heat exchange in the hydrogen heat exchange unit, the low-temperature hydrogen enters a carbon dioxide hydrogenation reaction unit after the temperature of the low-temperature hydrogen is raised, and the carbon dioxide obtained by the carbon dioxide hydrogenation reaction unit and the flue gas separation unit is subjected to hydrogenation reaction.

5. An oxycombustion process according to claim 3, characterized in that the oil gas mixture produced by the carbon dioxide hydrogenation reaction unit is separated in a separation unit to obtain a target product and a fuel gas, and part of the fuel gas is returned to the carbon dioxide hydrogenation reaction unit for adjusting the hydrogenation process.

6. An oxycombustion method according to claim 3, characterized in that the high temperature oxygen-poor air exchanges heat with normal temperature air in a waste heat recovery unit, and the high temperature air with the raised temperature of normal temperature air reacts with the micro oxygen carrier in the oxygen uptake unit.

7. An oxycombustion method according to any one of claims 3-6, characterized in that the reaction pressure of the combustion unit, the oxygen release unit, the carbon dioxide hydrogenation reaction unit, the hydrogen production unit, the oxygen uptake unit is 0.1-0.5 MPa;

preferably, the reactors of the oxygen release unit, the carbon dioxide hydrogenation reaction unit, the hydrogen production unit and the oxygen absorption unit are all fluidized bed reactors.

8. An oxycombustion process according to claim 7, characterized in that the reaction temperature of the oxygen release unit is 600 to 950 ℃;

Preferably, the reaction temperature of the hydrogen production unit is 550-900 ℃;

preferably, the reaction temperature of the combustion unit is 600-2000 ℃;

preferably, the volume fraction of oxygen in the oxygen-enriched gas is controlled to be 22-80%, and more preferably 25-50%.

9. An oxycombustion method according to claim 7, characterized in that the oxygen uptake unit employs a low pressure oxygen uptake process or a high pressure oxygen uptake process;

wherein the reaction temperature of the low-pressure oxygen absorption process is 530-800 ℃, and the reaction pressure is 0.1-0.5 MPa;

the reaction temperature of the high-pressure oxygen absorption process is 800-1000 ℃, and the reaction pressure is 0.5-5 MPa;

preferably, the oxygen carrier is selected from at least one of copper-based oxygen carriers, iron-based oxygen carriers, manganese-based oxygen carriers, cobalt-based oxygen carriers and perovskite oxygen carriers; more preferably an iron-based oxygen carrier.

10. An oxycombustion process according to claim 7, characterized in that the target product of the carbon dioxide hydrogenation reaction unit is selected from any one of olefin, methanol, dimethyl ether, gasoline and aromatic hydrocarbon;

when the target product is olefin, the corresponding reaction temperature is 200-500 ℃, the reaction pressure is 0.2-5 MPa, and the catalyst is Fe-Zn-Zr/zeolite molecular sieve;

When the target product is methanol, the corresponding reaction temperature is 150-500 ℃, the reaction pressure is 0.2-5 MPa, and the catalyst is a Cu-Zn catalyst;

when the target product is dimethyl ether, the corresponding reaction temperature is 150-500 ℃, the reaction pressure is 0.2-5 MPa, and the catalyst is a Cu-Zn/zeolite molecular sieve;

when the target product is gasoline, the corresponding reaction temperature is 150-500 ℃, the reaction pressure is 0.2-5 MPa, and the catalyst is Na-Fe/zeolite molecular sieve;

when the target product is aromatic hydrocarbon, the corresponding reaction temperature is 200-500 ℃, the reaction pressure is 0.2-5 MPa, and the catalyst is Zn-Al/zeolite molecular sieve.

Technical Field

The invention relates to the technical field of aerobic combustion, in particular to an oxygen-enriched combustion method.

Background

At present, all processes requiring gaseous oxygen to participate in combustion, such as waste liquid, waste gas, garbage and sludge incineration, gas, liquid and solid fuel combustion, catalyst regeneration, sulfur recovery and the like, mostly adopt air as an oxidant. The following problems are common to such combustion processes: (1) the combustion heat efficiency is low due to the factors of incomplete combustion reaction, insufficient recovery of flue gas heat, large amount of combustion heat taken away by nitrogen in the flue gas and the like; (2) the amount of flue gas generated by combustion is large, most of carbon dioxide in the flue gas is directly discharged, and the environment-friendly aim of low carbon emission reduction is not met; (3) NO in combusted flue gas_xAnd the content of the atmospheric pollutants is not easy to control.

In order to solve the problems of low combustion efficiency, difficult control of atmospheric pollutants in flue gas and the like, an oxygen-enriched or pure oxygen combustion technology can be adopted, and oxygen generation technologies such as a conventional low-temperature rectification technology, a membrane separation technology, a pressure swing adsorption technology and the like have higher cost, so that all the corresponding aerobic combustion processes need to be further improved.

In view of this, the invention is particularly proposed.

Disclosure of Invention

The invention aims to provide an oxygen-enriched combustion method, aiming at improving the combustion efficiency on the premise of not obviously increasing the cost.

The invention is realized by the following steps:

the embodiment of the invention provides an oxygen-enriched combustion method, which utilizes an oxygen absorption unit, an oxygen release unit and a combustion unit for processing and comprises the following steps: the oxygen carrier and oxygen-containing gas react in the oxygen absorption unit to obtain an oxygen-enriched oxygen carrier, the oxygen-enriched oxygen carrier releases oxygen in the oxygen release unit under the action of high-temperature flue gas to obtain oxygen-enriched gas and oxygen-poor oxygen carrier, and the oxygen-enriched gas and fuel are mixed in the combustion unit for combustion.

The invention has the following beneficial effects: the inventor creatively combines chemical chain oxygen generation and aerobic combustion reaction to realize oxygen-enriched combustion, utilizes the oxygen uptake unit to produce the oxygen-enriched oxygen carrier, and the oxygen-enriched oxygen carrier releases oxygen under the effect of high temperature flue gas to obtain oxygen-enriched gas, recycles the oxygen-enriched gas and fuel mixed combustion, can realize oxygen-enriched combustion under the prerequisite that does not significantly increase the cost of oxygen generation, improves the reaction efficiency of aerobic combustion. Meanwhile, the nitrogen content in the oxygen-enriched gas of the combustion improver is reduced, so that the combustion heat brought away by the nitrogen is reduced, the combustion heat efficiency is improved, and NO generated by combustion in the flue gas_xAnd the content of the pollutants is reduced. In addition, the main components in the flue gas obtained after combustion are carbon dioxide and water, so that the carbon dioxide is conveniently separated and utilized.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic diagram of a method of oxycombustion according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Aiming at the problem of high oxygen production cost of the oxygen-enriched combustion process in the prior art, the inventor provides a new process combining a chemical-looping air separation technology and aerobic combustion.

Specifically, the chemical-looping air separation technology is a new air separation technology, and the principle is that oxygen-enriched oxygen carriers are subjected to oxygen release reaction in an oxygen release reactor to generate oxygen, and micro-oxygen carriers or oxygen-poor oxygen carriers are subjected to oxidation regeneration in an oxygen absorption unit by reacting with oxygen in the air to generate the oxygen-enriched oxygen carriers. Compared with the conventional oxygen generation technology, the method has the advantages of low energy consumption, quick start, low cost, convenient operation and the like, and provides favorable conditions for the improvement and promotion of the aerobic combustion technology.

In the oxygen absorption unit, M-based micro-oxygen carrier M_xO_yWith O in an oxygen-containing gas₂Reacting under certain conditions to generate M-based oxygen-enriched oxygen carrier M_xO_y+1. The reaction equation is:

in the oxygen release unit, M-based oxygen-rich oxygen carrier M_xO_y+1Under certain conditions release O₂Generating an M-based oxygen-deficient oxygen carrier M_xO_y-1Generation of O₂Can be used for oxygen-enriched combustion. The reaction equation is:

in the hydrogen production unit, the M radicals in reduced form are poorOxygen carrier M_xO_y-1Reacting with water under certain conditions to generate M-based micro-oxygen carrier M_xO_yAnd hydrogen, the hydrogen produced can be used for hydrogenation reactions. The reaction equation is:

it is to be noted that the above oxygen-poor, oxygen-rich, and micro-oxygen are relative concepts, and are conventionally understood in the art, as M in the above reaction equation_xO_y-1Denotes an M-based oxygen-deficient carrier, M_xO_yDenotes a micro oxygen carrier, M_xO_y+1Represents an oxygen-rich oxygen carrier. The oxygen deficiency, the micro-oxygen and the rich oxygen only represent a molecular formula M_xO_y-1、M_xO_yAnd M_xO_y+1The quantity ratio of the elements O and M is increased in turn.

Referring to fig. 1, an embodiment of the present invention provides an oxygen-enriched combustion method, which mainly includes an oxygen absorption unit, an oxygen release unit, a combustion unit, a flue gas heat exchange unit, a hydrogen production unit, a flue gas separation unit, a carbon dioxide hydrogenation unit, and the like.

The oxygen-rich gas generated by the oxygen absorption unit and the oxygen release unit is used for the aerobic combustion reaction of the combustion unit, the main components of the generated high-temperature flue gas are water and carbon dioxide, the high-temperature flue gas passes through the flue gas heat exchange unit and the flue gas separation unit to obtain carbon dioxide, water and waste gas, the carbon dioxide is used for the carbon dioxide hydrogenation reaction, and the water is used for the hydrogen production unit.

Specifically, the oxygen absorption unit uses an oxygen carrier to react with an oxygen-containing gas to obtain an oxygen-rich oxygen carrier, and the oxygen release unit uses the oxygen-rich oxygen carrier to release oxygen under the action of high-temperature flue gas generated by the combustion unit to obtain an oxygen-rich gas and an oxygen-poor oxygen carrier (used for the hydrogen production unit). The combustion unit utilizes the oxygen-enriched gas to be mixed with fuel for combustion, simultaneously can heat the process materials to be processed, and collects the processed process materials or enters the next procedure. One part of high-temperature flue gas generated by combustion enters the oxygen release reaction unit to provide heat for the oxygen release reaction, and the other part of flue gas enters the flue gas heat exchange unit, enters the flue gas separation unit after the temperature of the flue gas exchanges heat with water is reduced.

In some embodiments, the oxygen absorption unit is configured to react air with an oxygen carrier (e.g., a micro-oxygen carrier generated by the hydrogen production unit) to obtain oxygen-depleted air with a higher temperature, the high-temperature oxygen-depleted air exchanges heat with normal-temperature air in the waste heat recovery unit, the high-temperature air after temperature rise reacts with the micro-oxygen carrier in the oxygen absorption unit, and the oxygen-depleted air after heat exchange is directly discharged after temperature reduction.

Additionally, the oxycombustion process provided by the embodiment of the invention has the following advantages: (1) the embodiment of the invention adopts chemical chain oxygen generation for oxygen-enriched combustion, compared with the conventional oxygen generation technology, the oxygen-enriched combustion method has the advantages of low energy consumption, quick start, low cost, convenient operation and the like, provides favorable conditions for oxygen-enriched combustion, adopts oxygen-enriched combustion reaction, and has the combustion reaction temperature far higher than the combustion temperature in the air, so that the combustion reaction is more thorough, and the combustion reaction efficiency is greatly improved; (2) using oxygen-enriched gas (N)₂Reduced content) as a combustion improver, N₂The combustion heat brought away is reduced, and simultaneously, the smoke discharge amount is also greatly reduced, so that the method is very favorable for energy conservation and emission reduction of the combustion unit; (3) production of NO in flue gas_xThe content is reduced, the main components of the flue gas are carbon dioxide and water, the capture and the comprehensive utilization of the carbon dioxide in the flue gas are facilitated, and the captured carbon dioxide can be directly used as a raw material for preparing target products such as methanol, olefin and the like and can also be sold as commodity carbon dioxide.

Further, the flue gas heat exchange unit exchanges heat between the high-temperature flue gas and the water obtained by the flue gas separation unit, recovers the heat of the high-temperature flue gas, and heats the water obtained by the flue gas separation unit to obtain water vapor. And (3) carrying out flue gas separation on the cooled flue gas in a flue gas separation unit to obtain water, carbon dioxide and waste gas, discharging or collecting and treating the separated waste gas through a chimney, and conveying the carbon dioxide to a carbon dioxide hydrogenation reaction unit for hydrogenation reaction. The water vapor and the oxygen-poor carrier react in the hydrogen production unit to generate high-temperature hydrogen-containing gas and a micro-oxygen carrier, the micro-oxygen carrier reacts with high-temperature air in the oxygen absorption unit to obtain an oxygen-rich carrier and high-temperature oxygen-poor air, and the high-temperature hydrogen-containing gas is treated and then used for hydrogenation reaction. Specifically, in the hydrogen production unit, water vapor reacts with the oxygen-deficient oxygen carrier, the oxygen-deficient oxygen carrier reacts with the water vapor and is converted into a micro-oxygen carrier, the micro-oxygen carrier enters the oxygen absorption unit, and the water vapor is converted into hydrogen. High-temperature hydrogen-containing gas generated by the hydrogen production unit enters the hydrogen heat exchange unit to exchange heat with low-temperature hydrogen from the hydrogen separation unit, the low-temperature hydrogen-containing gas with the reduced temperature enters the hydrogen separation unit to be separated to obtain water and low-temperature hydrogen, the low-temperature hydrogen is returned to the hydrogen heat exchange unit to exchange heat, the high-temperature hydrogen and carbon dioxide after being heated are subjected to hydrogenation reaction in the carbon dioxide hydrogenation reaction unit, and water obtained by the hydrogen separation unit is conveyed to the flue gas heat exchange unit to be heated.

The inventor creatively utilizes a chemical chain oxygen production process to match with a combustion unit, a carbon dioxide hydrogenation reaction unit and a hydrogen production unit to realize the recycling of raw materials, and the whole process has low operation cost and high raw material utilization rate. The flue gas generated by combustion can be utilized by coupling with a carbon dioxide hydrogenation process and a hydrogen production process, and can react with a catalyst and an oxygen carrier under different conditions, and organic matters with economic value can be prepared by a carbon dioxide hydrogenation reaction unit, so that the efficiency of aerobic combustion reaction is further improved, the emission of pollutants and carbon dioxide is reduced, and the problems that the efficiency of conventional aerobic combustion reaction is difficult to improve, the emission of pollutants, the flue gas is difficult to treat and the like are solved.

Further, the carbon dioxide and the hydrogen enter a carbon dioxide hydrogenation reaction unit to generate an oil-gas mixture under the action of a catalyst, and the oil-gas mixture enters a separation unit to be separated. And (4) feeding the separated target product into the next procedure, returning part of the remaining gas to the carbon dioxide hydrogenation reaction unit for regulating the carbon dioxide hydrogenation process, and feeding part of the remaining gas serving as fuel gas into a fuel gas pipe network.

In some embodiments, the oil-gas mixture generated by the hydrogenation reaction is separated in a separation unit to obtain a target product and a fuel gas, and part of the fuel gas is returned to the carbon dioxide hydrogenation reaction unit for reaction.

The following is a detailed description of the process parameters of each unit:

the reaction pressure of the combustion unit, the oxygen release unit, the carbon dioxide hydrogenation reaction unit, the hydrogen production unit and the oxygen absorption unit is 0.1-0.5 MPa, such as 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa and the like.

Specifically, the reactors of the oxygen release unit, the carbon dioxide hydrogenation reaction unit, the hydrogen production unit and the oxygen absorption unit can be conventional reactors such as a fluidized bed, a fixed bed and a moving bed, and are preferably fluidized bed reactors.

The oxygen absorption unit adopts a low-pressure oxygen absorption process or a high-pressure oxygen absorption process; wherein the reaction temperature of the low-pressure oxygen absorption process is 530-800 ℃ (such as 530 ℃, 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃ and the like), and the reaction pressure is 0.1-0.5 MPa (such as 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa and the like); the high-pressure oxygen absorption process has a reaction temperature of 800 to 1000 ℃ (such as 800 ℃, 850 ℃, 900 ℃, 950 ℃, 1000 ℃ and the like) and a reaction pressure of 0.5 to 5MPa (0.5MPa, 1.0MPa, 2.0MPa, 3.0MPa, 4.0MPa, 5.0MPa and the like).

The reaction temperature of the oxygen release unit is 600-950 ℃, such as 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃, 950 ℃ and the like. The volume fraction of oxygen in the oxygen-enriched gas entering the combustion unit is controlled to be 22-80%, preferably 25-50%, and the oxygen concentration of the oxygen-enriched gas can be adjusted by controlling the amount of flue gas entering the oxygen release reactor and the oxygen carrier circulation amount in the actual operation process. The combustion efficiency is further improved and the generation of nitrogen oxides is reduced by controlling the content of the flue gas in the oxygen-enriched gas.

Further, the oxygen carrier comprises one or more of a metal oxygen carrier and a nonmetal oxygen carrier, and the metal oxygen carrier comprises at least one of a copper-based oxygen carrier, an iron-based oxygen carrier, a manganese-based oxygen carrier and a cobalt-based oxygen carrier, and can be a single oxygen carrier or a composite oxygen carrier; the nonmetal oxygen carrier is a perovskite oxygen carrier. In a preferred embodiment, the oxygen carrier is an iron-based composite oxygen carrier, i.e. a composite oxygen carrier formed of an iron-based oxygen carrier.

Further, the reaction temperature of the combustion unit is 600-2000 ℃, and the specific combustion temperature is selected according to the types of the materials and fuels to be processed, such as 600 ℃, 700 ℃, 800 ℃, 900 ℃, 1000 ℃, 1100 ℃, 1200 ℃, 1300 ℃, 1400 ℃, 1500 ℃, 1600 ℃, 1700 ℃, 1800 ℃, 1900 ℃, 2000 ℃ and the like. The fuel can be gaseous, solid or liquid fuel, such as coal, raw oil, natural gas, refinery gas, coal water slurry, etc.

Specifically, the combustion unit comprises all aerobic combustion reaction processes, such as sludge combustion, waste liquid and waste gas incineration, sulfur recovery combustion, catalyst regeneration, pulverized coal combustion, heating furnace fuel combustion, metallurgical furnace fuel combustion and the like.

Further, the target product of the carbon dioxide hydrogenation reaction unit is selected from any one of olefin, methanol, dimethyl ether, gasoline and aromatic hydrocarbon; wherein when the target product is olefin, the corresponding reaction temperature is 200-500 ℃, the reaction pressure is 0.2-5 MPa, and the catalyst is Fe-Zn-Zr/zeolite molecular sieve; when the target product is methanol, the corresponding reaction temperature is 150-500 ℃, the reaction pressure is 0.2-5 MPa, and the catalyst is a Cu-Zn catalyst; when the target product is dimethyl ether, the corresponding reaction temperature is 150-500 ℃, the reaction pressure is 0.2-5 MPa, and the catalyst is a Cu-Zn/zeolite molecular sieve; when the target product is gasoline, the corresponding reaction temperature is 150-500 ℃, the reaction pressure is 0.2-5 MPa, and the catalyst is Na-Fe/zeolite molecular sieve; when the target product is aromatic hydrocarbon, the corresponding reaction temperature is 200-500 ℃, the reaction pressure is 0.2-5 MPa, and the catalyst is Zn-Al/zeolite molecular sieve.

It should be noted that carbon dioxide reacts with hydrogen under a certain condition under the action of a catalyst to prepare olefin, methanol, aromatic hydrocarbon, gasoline, dimethyl ether, etc., and specifically, the selection of raw materials, catalyst and reaction conditions can be performed according to the desired target product, and reference can be made to the existing process, which is not described herein in any more detail.

Furthermore, the reaction temperature of the hydrogen production unit is 550-900 ℃, such as 550 ℃, 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃ and the like.

It is necessary to supplement that the flue gas separation unit, the hydrogen separation unit and the separation unit for processing the oil-gas mixture can adopt one or more of technologies such as membrane separation, pressure swing adsorption, solvent absorption, low-temperature separation, fractionating tower separation, oil-gas separation and the like.

The features and properties of the present invention are described in further detail below with reference to examples.

Example 1

Referring to fig. 1, an embodiment of the present invention provides an oxygen-enriched combustion method, which includes the following steps and reaction conditions:

the combustion unit adopts a tubular heating furnace fuel gas combustion process, the oxygen absorption unit is a low-pressure oxygen absorption process (the operation pressure is 0.3MPa), the oxygen release unit, the hydrogen production unit, the oxygen absorption unit and the reaction pressure are all 0.25MPa, the oxygen carrier is an iron-based composite oxygen carrier, the catalyst is a Cu-Zn catalyst for preparing methanol, and the carbon dioxide hydrogenation reaction unit has the reaction temperature of 350 ℃ and the pressure of 3 MPa.

(1) Normal temperature air at 25 ℃ enters a waste heat recovery unit, exchanges heat with high temperature oxygen-poor air, rises to about 600 ℃, enters an oxygen absorption unit, and is mixed with micro-oxygen carrier Fe at 700 DEG C ₃O₄(the quantity ratio of the O element to the Fe element is 4:3) to obtain 650-800 ℃ high-temperature oxygen-poor air and an oxygen-rich oxygen carrier Fe₂O₃(the quantity ratio of the O element to the Fe element is 3:2), the high-temperature oxygen-poor air enters a waste heat recovery unit to exchange heat with normal-temperature air, and the temperature is reduced to below 50 ℃ and is directly discharged.

(2) 650-800 ℃ oxygen-enriched oxygen carrier Fe₂O₃And (3) entering an oxygen release unit, and releasing oxygen under the action of high-temperature flue gas at 600-850 ℃ to obtain oxygen-poor oxygen carriers FeO (the quantity ratio of O element to Fe element is 1:1) and oxygen-enriched gas (the oxygen content is about 43%) at 600-750 ℃. The oxygen-poor oxygen carrier FeO enters the hydrogen production unit, and the oxygen-rich gas enters the combustion unit.

(3) The oxygen-deficient oxygen carrier FeO at the temperature of 600-750 ℃ enters the hydrogen production unit to react with the steam at the temperature of 250-300 ℃ from the flue gas heat exchange unit, most of the steam is converted into hydrogen, and the micro-oxygen carrier Fe at the temperature of 630-730 ℃ is generated₃O₄And a high temperature hydrogen-containing gas. Micro-oxygen carrier Fe₃O₄Returning to the oxygen absorption unit, and introducing high-temperature hydrogen-containing gas into hydrogen for heat exchangeAnd (4) units.

(4) The oxygen-enriched gas enters the combustion unit to be combusted with the fuel gas to release heat, the materials processed by the combustion unit are heated, and the processed materials enter the subsequent process. And returning one part of high-temperature flue gas at 600-850 ℃ generated by combustion to the oxygen release unit, and introducing the other part of flue gas at 300-500 ℃ into the flue gas heat exchange unit, so that water from the flue gas separation unit and the hydrogen separation unit is changed into steam at 250-300 ℃ and enters the hydrogen production unit.

(5) The high-temperature flue gas passes through the flue gas heat exchange unit, the temperature is reduced to 50-100 ℃, the high-temperature flue gas enters the flue gas separation unit, carbon dioxide and water in the high-temperature flue gas are separated, and the rest of a small amount of waste gas is collected and treated. And the separated carbon dioxide is pressurized to 3MPa by a compressor and enters a carbon dioxide hydrogenation reaction unit, and the separated water returns to the flue gas heat exchange unit.

(6) The high-temperature hydrogen-containing gas at the temperature of 630-730 ℃ enters a hydrogen heat exchange unit, the temperature is reduced to 50-100 ℃, and the high-temperature hydrogen-containing gas enters a hydrogen separation unit to separate low-temperature hydrogen and water. And water enters the flue gas heat exchange unit for heat exchange and temperature rise, the low-temperature hydrogen is boosted to 3MPa and returns to the hydrogen heat exchange unit for heat exchange with the high-temperature hydrogen-containing gas, and the temperature rises to 350-450 ℃ and enters the carbon dioxide hydrogenation reaction unit.

(7) The carbon dioxide and the hydrogen in the carbon dioxide hydrogenation reaction unit react under the pressure of 3MPa and the action of a Cu-Zn catalyst to prepare the methanol, the conversion rate of the carbon dioxide is higher than 30 percent, and the selectivity of the methanol is higher than 80 percent. The oil-gas mixture containing methanol enters a separation unit for oil-gas separation, the target product methanol is collected and processed, one part of the rest gas returns to a carbon dioxide hydrogenation reaction unit to adjust the reaction process, and the other part of the rest gas enters a gas pipe network as fuel gas.

Comparative example 1

The comparative example provides a combustion method, the combustion unit adopts general high-temperature air to replace the oxygen-enriched gas in the example 1 for reaction, taking a combustion unit with the heat load of 12MW as an example, the combustion adopts air as a combustion improver, and the oxygen content in the combustion improver is about 21 percent.

Test examples

The combustion products of example 1 and comparative example 1 were tested by conventional methodsRaw smoke gas amount and NO in smoke gas_xContent, carbon dioxide concentration in flue gas and combustion heat efficiency.

The results show that the conventional combustion method in comparative example 1 produces 22800kg/h of flue gas, and NO in the flue gas_xThe content is 45mg/m³The combustion heat efficiency is 92.5 percent, and the concentration of carbon dioxide in the flue gas is 14 percent, so that the flue gas is not convenient to separate, purify and utilize.

And the energy consumption for oxygen production is 0.12 kW.h/kg, which is 50% of that for the traditional oxygen production, in example 1 by adopting chemical chain oxygen production. Oxygen-enriched gas obtained by chemical chain oxygen generation is used as a combustion improver for combustion reaction, and compared with the traditional combustion method in which air is used as the combustion improver, the oxygen-enriched gas combustion improver has the advantages of high thermal efficiency, small smoke discharge, less pollutants and the like.

Example 1 oxygen-enriched gas obtained by chemical chain oxygen production is used for combustion reaction, the oxygen content in the oxygen-enriched gas of the combustion improver is about 43 percent, the smoke generated by combustion is 11000kg/h, and NO in the smoke _xThe content is 15mg/m³The combustion heat efficiency is 95.2 percent, the concentration of carbon dioxide in the flue gas is 33 percent, and the separation, purification and utilization are convenient.

In summary, the oxygen-enriched combustion method provided by the embodiment of the present invention combines the chemical chain oxygen generation and the oxy-combustion reaction to realize the oxygen-enriched combustion, and further separates the flue gas after the combustion reaction to obtain relatively pure water and carbon dioxide, the carbon dioxide performs carbon dioxide hydrogenation, and the water is used for the hydrogen production unit, so that the coupling of a plurality of reaction units is realized, and the oxygen-enriched combustion method has the following advantages:

(1) the aerobic combustion reaction efficiency is greatly improved. The conventional aerobic combustion reaction adopts air as a combustion improver, and nitrogen in the air can take away a large amount of combustion heat. The oxygen-enriched combustion reaction reduces the content of nitrogen in the oxygen-enriched gas of the combustion improver, the combustion reaction temperature is far higher than the combustion temperature in the air, the combustion reaction is more thorough, and the combustion reaction efficiency and the thermal efficiency are greatly improved.

(2) Can realize the effective utilization of carbon dioxide (such as preparing methanol by hydrogenation), prepare organic matters with economic value, and have obvious economic and environmental protection benefits. The embodiment of the invention realizes the oxygen-enriched combustion of the aerobic combustion reaction by utilizing the chemical chain oxygen production technology, and simultaneously utilizes the generated flue gas to react with the catalyst and the oxygen carrier under different conditions to complete the carbon dioxide hydrogenation process to prepare the organic matter with economic value, thereby having obvious economic and environmental benefits.

(3) Can greatly reduce the emission of pollutants and has obvious environmental protection benefit. In the conventional process, the aerobic combustion reaction is directly contacted with air for combustion, the flue gas amount is large, and the flue gas treatment process is complex. In the embodiment of the invention, the flue gas generated by oxygen-enriched combustion reacts with the catalyst and the oxygen carrier under different conditions to complete the carbon dioxide hydrogenation reaction, the carbon dioxide conversion rate is 20-60%, the emission of carbon dioxide is greatly reduced, the content of nitrogen in the oxygen-enriched gas of the combustion improver is reduced, and NO generated by combustion in the flue gas is reduced_xThe content of pollutants is reduced, the environment-friendly benefit is good, and the strategic target of low carbon and emission reduction is met.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.