System and method for preparing acrylic acid by using waste gas containing carbon monoxide

Abstract

The invention discloses a system and a method for preparing acrylic acid by using waste gas containing carbon monoxide, and belongs to the technical field of biological fermentation conversion. The system comprises a biological fermentation acetic acid production unit, a biological fermentation 3-hydracrylic acid production unit, a 3-hydracrylic acid purification unit and an acrylic acid production unit which are connected in sequence. Acetic acid is prepared by performing biological fermentation on carbon monoxide in the waste gas; acetic acid is used for biological fermentation, 3-hydracrylic acid is prepared, separation, extraction and dehydration are carried out, and acrylic acid is prepared. According to the method, the waste gas containing carbon monoxide is used as a raw material to prepare acrylic acid, carbon monoxide is fixed through a biological fermentation technology, the problems of high dependency degree of fossil-based raw materials and high production cost in an existing acrylic acid preparation method can be solved, and successful preparation from carbon resources to high-added-value acrylic acid is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of biological fermentation conversion, and particularly relates to a system and method for preparing acrylic acid by utilizing waste gas containing carbon monoxide. Background Art

[0002] Acrylic acid is an important organic chemical raw material. Its polymers and copolymers help improve the durability, scratch resistance and overall performance of products. It is widely used in paints, adhesives, coatings, plastics, pharmaceuticals and other fields. In recent years, with the growth of population and the improvement of hygiene awareness, the demand for absorbent products such as disposable diapers and feminine hygiene products has continued to rise. As the core raw material of absorbent polymers, acrylic acid will continue to benefit from this trend. In addition, as countries protect water resources and continue to develop water treatment technology, the application of acrylic products (such as anionic polyelectrolytes) in sewage treatment will continue to expand, helping global water resource management.

[0003] At present, the production methods of acrylic acid include propylene oxidation method: propylene is oxidized to produce acrylic acid under the action of a catalyst; acrylonitrile hydrolysis method: acrylonitrile is hydrolyzed in the presence of a catalyst to produce acrylamide, which is then converted into acrylic acid through a hydrolysis reaction; acetylene carbonylation method: acetylene, carbon monoxide and water are synthesized into acrylic acid under the action of a catalyst. However, these existing production methods are highly dependent on fossil fuels and have high production costs. Therefore, it is of great significance to find a low-carbon, green method for producing acrylic acid.

[0004] Carbon monoxide is a colorless, tasteless, odorless toxic gas that can bind to hemoglobin. Long-term exposure to high concentrations of carbon monoxide can damage the nervous system and cardiovascular system. Usually, industrial production, transportation, household stoves, heating boilers and other fields will produce waste gas containing carbon monoxide. These waste gases containing carbon monoxide are discharged into the atmosphere and will react with other chemicals in the atmosphere to generate secondary pollutants such as photochemical smog, which will not only affect air quality, but may also cause harm to human health. Summary of the invention

[0005] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a system and method for preparing acrylic acid using waste gas containing carbon monoxide, so as to solve the problems of high dependence on fossil-based raw materials and high production costs in the existing acrylic acid preparation methods.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The first aspect of the present invention discloses a system for preparing acrylic acid using waste gas containing carbon monoxide, comprising a bio-fermentation acetic acid production unit, a bio-fermentation 3-hydroxypropionic acid production unit, a 3-hydroxypropionic acid purification unit and an acrylic acid production unit connected in sequence; The bio-fermentation acetic acid production unit is used to carry out bio-fermentation using carbon monoxide in the waste gas as a substrate to obtain a fermentation liquid containing acetic acid; The biological fermentation unit for producing 3-hydroxypropionic acid is used for biological fermentation with acetic acid as a substrate to obtain a fermentation liquid containing 3-hydroxypropionic acid; A 3-hydroxypropionic acid purification unit, used to separate and extract the fermentation broth containing 3-hydroxypropionic acid to obtain 3-hydroxypropionic acid; Acrylic acid production unit, used to dehydrate 3-hydroxypropionic acid to produce acrylic acid.

[0007] Preferably, it also includes a cogeneration unit, which is respectively connected to the biological fermentation acetic acid production unit, the biological fermentation 3-hydroxypropionic acid production unit, the 3-hydroxypropionic acid purification unit and the acrylic acid production unit, and is used to convert the waste generated in the production process into electrical energy, thermal energy and nitrogen-containing sludge.

[0008] Further preferably, the cogeneration unit comprises a second mixer, an anaerobic fermentation tank, a third flash tank, a third mixer, a combustion chamber, a gas turbine and a seventh heat exchanger connected in sequence, the second mixer is used to treat the waste liquid and waste residue generated by the acrylic acid production unit and the 3-hydroxypropionic acid purification unit, and the third mixer is used to treat the waste gas generated by the third flash tank, the biological fermentation acetic acid production unit and the biological fermentation 3-hydroxypropionic acid production unit.

[0009] Further preferably, it also includes a third compressor and a centrifuge, the third compressor is connected to the combustion chamber for inputting compressed air into the combustion chamber, and the centrifuge is connected to the third flash tank for centrifuging the nitrogen-containing sludge produced by fermentation in the third flash tank to form nitrogen fertilizer.

[0010] Preferably, the biological fermentation acetic acid production unit comprises a first compressor, a first heat exchanger, a first mixer, a first fermentation tank and a first flash tank connected in sequence, the first fermentation tank is inoculated with Moorella, and the first flash tank is connected to the biological fermentation 3-hydroxypropionic acid production unit.

[0011] Further preferably, the bio-fermentation acetic acid production unit further comprises a first storage tank, a first pump and a second heat exchanger connected in sequence, and the second heat exchanger is connected to the first mixer.

[0012] Preferably, the biological fermentation 3-hydroxypropionic acid production unit includes a second pump, a third heat exchanger, a second fermentation tank and a second flash tank connected in sequence, the second fermentation tank is inoculated with Vibrio natrium, the second pump is connected to the biological fermentation acetic acid production unit, and the second flash tank is connected to the 3-hydroxypropionic acid purification unit.

[0013] Further preferably, the biological fermentation unit for producing 3-hydroxypropionic acid also includes a second storage tank, a third pump and a fourth heat exchanger, the second storage tank is used to provide the second fermentation tank with the buffer and nutrients required for the biological reaction, and the second storage tank, the third pump, the fourth heat exchanger and the second fermentation tank are connected in sequence.

[0014] Preferably, the 3-hydroxypropionic acid purification unit includes a third storage tank, a fourth pump, a dissolved air flotation reactor, an extractive distillation tower, a separator, a first vacuum distillation tower, a fifth pump and a sixth heat exchanger connected in sequence, the third storage tank is connected to the biological fermentation 3-hydroxypropionic acid production unit, and the sixth heat exchanger is connected to the acrylic acid production unit.

[0015] Further preferably, the 3-hydroxypropionic acid purification unit further comprises a second compressor, a fifth heat exchanger and an air storage device, and the second compressor, the fifth heat exchanger, the air storage device and the dissolved air flotation reactor are connected in sequence.

[0016] Preferably, the acrylic acid production unit comprises a dehydration reactor, a second vacuum distillation tower and a third vacuum distillation tower which are connected in sequence, and the dehydration reactor is connected to the 3-hydroxypropionic acid purification unit.

[0017] The second aspect of the present invention discloses a method for preparing acrylic acid using waste gas containing carbon monoxide, wherein carbon monoxide in the waste gas is subjected to biological fermentation to obtain acetic acid; acetic acid is subjected to biological fermentation to obtain 3-hydroxypropionic acid, which is separated, extracted and dehydrated to obtain acrylic acid.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a system for preparing acrylic acid using waste gas containing carbon monoxide, wherein carbon monoxide in the waste gas containing carbon monoxide is used as a raw material to generate acetic acid through biological fermentation; acetic acid is used as a raw material to perform secondary biological fermentation and product purification to obtain 3-hydroxypropionic acid, and then 3-hydroxypropionic acid is used as a raw material to obtain acrylic acid through dehydration, thereby resource-utilizing carbon monoxide in the waste gas and obtaining acrylic acid through biological transformation. In this method, first, acrylic acid is prepared using carbon monoxide in the waste gas as a raw material, which can reduce greenhouse gas emissions while resource-utilizing carbon sources, realize the successful preparation of high-value-added acrylic acid from carbon resources, reduce production costs, and replace the existing method for preparing acrylic acid from fossil-based raw materials. Second, a microbial fermentation method is adopted to metabolize waste gas and convert it into other compounds, which not only helps to reduce greenhouse gas emissions, but also realizes resource recycling and improves the economic value of waste gas. Therefore, this method can solve the problem of high dependence on fossil-based raw materials in the existing method for preparing acrylic acid.

[0019] Furthermore, the cogeneration unit can produce biogas and nitrogen-containing sludge through anaerobic fermentation of the waste residues and wastewater generated in the whole process. The biogas and unreacted waste gas can be burned to supply electricity and heat for the whole process. The nitrogen-containing sludge can be dehydrated and sold as a nitrogen fertilizer by-product, thereby achieving efficient energy recovery and utilization and improving process economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a process flow chart of a method for preparing acrylic acid by using waste gas containing carbon monoxide; Figure 2 The present invention is a schematic diagram of a system for preparing acrylic acid by utilizing waste gas containing carbon monoxide.

[0021] In the figure: 1-first compressor; 2-first heat exchanger; 3-first storage tank; 4-first pump; 5-second heat exchanger; 6-first mixer; 7-first fermentation tank; 8-first flash tank; 9-second pump; 10-third heat exchanger; 11 -second storage tank; 12-third pump; 13-fourth heat exchanger; 14-second fermentation tank; 15-second flash tank; 16-third storage tank; 17-fourth pump; 18-dissolved air flotation reactor; 19-second compressor; 20-fifth heat exchanger; 21-gas storage tank; 22-extractive distillation tower; 23-separator; 24-first vacuum distillation tower; 25-fifth pump; 26-sixth heat exchanger; 27-dehydration reactor; 28-second vacuum distillation tower; 29-third vacuum distillation tower; 30-second mixer; 31-anaerobic fermentation tank; 32-third flash tank; 33-third mixer; 34-combustion chamber; 35-third compressor; 36-gas turbine; 37-seventh heat exchanger; 38-centrifuge. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] See also Figure 1 The present invention provides a method for preparing acrylic acid by using waste gas containing carbon monoxide, comprising: (1) Bio-fermentation to produce acetic acid: Bio-fermentation is carried out using waste gas containing carbon monoxide as a substrate, and the fermentation product is subjected to gas-liquid separation to obtain a fermentation liquid containing acetic acid; (2) Bio-fermentation to produce 3-hydroxypropionic acid: Bio-fermentation is carried out using acetic acid as a substrate, and the fermentation product is subjected to gas-liquid separation to obtain a fermentation broth containing 3-hydroxypropionic acid; (3) Purification of 3-hydroxypropionic acid: solid-liquid separation and extraction are performed on the fermentation broth of 3-hydroxypropionic acid to obtain 3-hydroxypropionic acid; (4) Acrylic acid production: The purified 3-hydroxypropionic acid is dehydrated to obtain acrylic acid.

[0025] Furthermore, a heat and power cogeneration step may be added to the above method.

[0026] (5) Cogeneration: The waste residues and wastewater generated in the whole process are subjected to anaerobic fermentation to produce biogas and nitrogen-containing sludge. The biogas is mixed with the waste gas generated in the process of producing acetic acid by biological fermentation and 3-hydroxypropionic acid by biological fermentation and burned. The combustion gas is used to generate electricity and heat through heat exchange equipment to supply the electricity and heat energy required for the whole process. The nitrogen-containing sludge is sold as a by-product of nitrogen fertilizer.

[0027] The invention provides a system for preparing acrylic acid by using waste gas containing carbon monoxide, comprising a biological fermentation acetic acid production unit, a biological fermentation 3-hydroxypropionic acid production unit, a 3-hydroxypropionic acid purification unit and an acrylic acid production unit which are connected in sequence.

[0028] The bio-fermentation acetic acid production unit is used to use carbon monoxide in the waste gas containing carbon monoxide as a substrate, in the presence of Moorella ( Moorella thermoacetica ) to carry out biological fermentation, separate the biological fermentation products into gas and liquid, and obtain the fermentation liquid containing acetic acid.

[0029] The 3-hydroxypropionic acid unit produced by biological fermentation is used to use acetic acid in the fermentation broth containing acetic acid as a substrate in Vibrio natriuresis ( Vibrio natriegens ) to carry out biological fermentation, and to separate the biological fermentation product into gas and liquid to obtain a fermentation liquid containing 3-hydroxypropionic acid.

[0030] The 3-hydroxypropionic acid purification unit is used to perform solid-liquid separation on the fermentation liquid containing 3-hydroxypropionic acid by dissolved air flotation, and purify it by extraction and distillation to obtain 3-hydroxypropionic acid.

[0031] Acrylic acid production unit, used to dehydrate 3-hydroxypropionic acid to produce acrylic acid.

[0032] Furthermore, a cogeneration unit may be added to the above system.

[0033] The cogeneration unit is used to produce biogas and nitrogen-containing sludge through anaerobic fermentation of waste residues and wastewater generated in the whole process, and to burn the waste gas generated by the biogas, biological fermentation acetic acid production unit and biological fermentation 3-hydroxypropionic acid production unit to supply the required electricity and heat energy for the whole process.

[0034] The present invention is further described below by using steel mill tail gas as waste gas containing carbon monoxide through specific examples. It should be understood that any waste gas containing carbon monoxide other than steel mill tail gas is applicable to the present method, and these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

[0035] In the following embodiments, the "steel tail gas" mentioned is commonly known as steel tail gas, which is waste gas generated during the steel smelting process. Its main components include nitrogen, carbon monoxide, carbon dioxide, hydrogen, and a small amount of harmful substances such as sulfur dioxide, nitrogen oxides, tar and dust. Among them, carbon monoxide, hydrogen and methane are the main effective components of steel tail gas.

[0036] A system for preparing acrylic acid using steel plant tail gas, see Figure 2 , including a bio-fermentation acetic acid production unit, a bio-fermentation 3-hydroxypropionic acid production unit, a 3-hydroxypropionic acid purification unit and an acrylic acid production unit connected in sequence. In addition, it also includes a cogeneration unit, which is connected to the bio-fermentation acetic acid production unit, the bio-fermentation 3-hydroxypropionic acid production unit, the 3-hydroxypropionic acid purification unit and the acrylic acid production unit.

[0037] The bio-fermentation acetic acid production unit comprises a first compressor 1, a first heat exchanger 2, a first storage tank 3, a first pump 4, a second heat exchanger 5, a first mixer 6, a first fermentation tank 7 and a first flash tank 8. The first compressor 1, the first heat exchanger 2, the first mixer 6, the first fermentation tank 7 and the first flash tank 8 are connected in sequence; the first compressor 1 is used to receive and pressurize the steel mill tail gas, and the first heat exchanger 2 is used to adjust the temperature of the pressurized steel mill tail gas to the required temperature of the bioreactor. The first storage tank 3, the first pump 4, the second heat exchanger 5 and the first mixer 6 are connected in sequence, and the first storage tank 3 is used to receive buffers and nutrients for biological reaction; the buffers include but are not limited to pH buffers, and the nutrients include but are not limited to nitrogen sources and trace elements; the first mixer 6 is used to receive the steel mill tail gas from the first heat exchanger 2, the buffers and nutrients from the second heat exchanger 5, and mix them and send them to the first fermentation tank 7. The first fermentation tank 7 is inoculated with Moore's bacteria, and the first fermentation tank 7 is used for biological fermentation of steel mill tail gas, buffer and nutrients under the action of Moore's bacteria to obtain a fermentation liquid containing acetic acid and biomass. The first flash tank 8 is used to separate the remaining gas and fermentation liquid after biological fermentation; the first flash tank 8 is provided with a fermentation liquid outlet and a waste gas outlet on its body, and the waste gas outlet of the first flash tank 8 is connected to the inlet of the third mixer 33 for mixing waste.

[0038] The biological fermentation unit for producing 3-hydroxypropionic acid comprises a second pump 9, a third heat exchanger 10, a second storage tank 11, a third pump 12, a fourth heat exchanger 13, a second fermentation tank 14 and a second flash tank 15. The fermentation liquid outlet of the first flash tank 8 is connected to the second pump 9, the third heat exchanger 10, the second fermentation tank 14 and the second flash tank 15 in sequence. The second pump 9 is used to pressurize the fermentation liquid containing acetic acid and biomass obtained by the biological fermentation unit for producing acetic acid and transport it to the third heat exchanger 10. After heat exchange in the third heat exchanger 10, the fermentation liquid containing acetic acid and biomass enters the second fermentation tank 14 for biological fermentation. The second storage tank 11, the third pump 12, the fourth heat exchanger 13, the second fermentation tank 14 and the second flash tank 15 are connected in sequence. The second storage tank 11 is used to receive buffers and nutrients for biological reaction; the buffer includes but is not limited to pH buffers, and the nutrients include but are not limited to nitrogen sources and trace elements; the third pump 12 is used to pressurize the buffer and nutrients; the pressurized mixture is received by the fourth heat exchanger 13, and the fourth heat exchanger 13 is used to adjust the temperature of the buffer and nutrients and send them to the second fermentation tank 14. The second fermentation tank 14 is inoculated with Vibrio natrii, and the second fermentation tank 14 is used to allow acetic acid, buffer and nutrients to be fermented biologically under the action of Vibrio natrii to obtain a fermentation liquid containing 3-hydroxypropionic acid and biomass. The second flash tank 15 is used to separate the remaining gas and fermentation liquid after biological fermentation; the second flash tank 15 body is provided with a fermentation liquid outlet and a waste gas outlet, and the waste gas outlet of the second flash tank 15 is connected to the inlet of the third mixer 33 for mixing waste.

[0039] The 3-hydroxypropionic acid purification unit includes a third storage tank 16, a fourth pump 17, a dissolved air flotation reactor 18, a second compressor 19, a fifth heat exchanger 20, a gas storage tank 21, an extractive distillation tower 22, a separator 23, a first vacuum distillation tower 24, a fifth pump 25 and a sixth heat exchanger 26. The fermentation liquid outlet of the second flash tank 15 is connected to the third storage tank 16, the fourth pump 17, the dissolved air flotation reactor 18, the extractive distillation tower 22, the separator 23, the first vacuum distillation tower 24, the fifth pump 25 and the sixth heat exchanger 26 in sequence; the third storage tank 16 is used to receive the fermentation liquid containing 3-hydroxypropionic acid and biomass, and the fourth pump 17 is used to pressurize the fermentation liquid containing 3-hydroxypropionic acid and biomass. The second compressor 19, the fifth heat exchanger 20, the air storage 21 and the dissolved air flotation reactor 18 are connected in sequence. The second compressor 19 is used to receive and compress air, the fifth heat exchanger 20 is used for temperature control, the air storage 21 is used to store compressed air, and the air storage 21 is used for dissolving air. The dissolved air flotation reactor 18 is used to use compressed air and an external flocculant to perform solid-liquid separation on the biomass in the fermentation liquid containing 3-hydroxypropionic acid and biomass. The dissolved air flotation reactor 18 body is provided with a fermentation liquid outlet and a waste residue outlet. The waste residue outlet of the dissolved air flotation reactor 18 is connected to the inlet of the second mixer 30, which is used to send the mixed waste to the second mixer 30. The fermentation liquid outlet of the dissolved air flotation reactor 18 is connected to the inlet of the extractive distillation tower 22. The fermentation liquid containing 3-hydroxypropionic acid obtained after solid-liquid separation is mixed with an extractant in the extractive distillation tower 22 to obtain a mixed solution containing 3-hydroxypropionic acid and an extractant, so that the 3-hydroxypropionic acid in the mixed solution can be extracted by the extractant. The separator 23 is used to separate the waste liquid in the mixed solution containing 3-hydroxypropionic acid and the extractant; the separator 23 body is provided with a mixed liquid outlet containing 3-hydroxypropionic acid and a waste liquid outlet, the waste liquid outlet of the separator 23 is connected to the inlet of the second mixer 30, and is used to send the waste liquid to the second mixer 30, the mixed liquid outlet containing 3-hydroxypropionic acid of the separator 23 is connected to the first vacuum distillation tower 24, the first vacuum distillation tower 24 is used to separate the extractant and 3-hydroxypropionic acid, the top of the first vacuum distillation tower 24 is provided with an extractant outlet, the extractant outlet is connected to the distillation tower 22, after the extractant flows out through the extractant outlet, it enters the extractive distillation tower 22 for reuse; the bottom of the first vacuum distillation tower 24 is provided with a 3-hydroxypropionic acid outlet, the 3-hydroxypropionic acid outlet is connected to the fifth pump 25, after the 3-hydroxypropionic acid flows out through the 3-hydroxypropionic acid outlet, it enters the fifth pump 25 for pressurization treatment, and then undergoes heat exchange in the fourth heat exchanger 26.

[0040] The acrylic acid production unit includes a dehydration reactor 27, a second vacuum distillation tower 28 and a third vacuum distillation tower 29 connected in sequence. The outlet of the sixth heat exchanger 26 is connected to the inlet of the dehydration reactor 27, and the dehydration reactor 27 is used to dehydrate the high-purity 3-hydroxypropionic acid obtained by the 3-hydroxypropionic acid purification unit to generate acrylic acid. The second vacuum distillation tower 28 is used to separate the 3-hydroxypropionic acid and acrylic acid that are not completely dehydrated. The bottom of the second vacuum distillation tower 28 is provided with a 3-hydroxypropionic acid outlet, which is connected to the dehydration reactor 27. The 3-hydroxypropionic acid outlet is connected to the dehydration reactor 27. The 3-hydroxypropionic acid that is not completely dehydrated flows out from the bottom of the second vacuum distillation tower 28 and refluxes to the dehydration reactor 27; the top of the second vacuum distillation tower 28 is provided with an acrylic acid outlet, which is connected to the third vacuum distillation tower 29, and the separated acrylic acid flows from the acrylic acid outlet to the third vacuum distillation tower 29. The bottom of the third vacuum distillation tower 29 is provided with an acrylic acid outlet, and high-purity acrylic acid flows out of the bottom as a product; the top of the third vacuum distillation tower 29 is provided with a waste liquid outlet, which is connected to the second mixer 30, and the separated waste liquid flows out from the top of the tower and enters the second mixer 30.

[0041] The cogeneration unit includes a second mixer 30 , an anaerobic fermentation tank 31 , a third flash tank 32 , a third mixer 33 , a combustion chamber 34 , a third compressor 35 , a gas turbine 36 , a seventh heat exchanger 37 and a centrifuge 38 . The second mixer 30, the anaerobic fermentation tank 31, the third flash tank 32, the third mixer 33, the combustion chamber 34, the gas turbine 36 and the seventh heat exchanger 37 are connected in sequence. The second mixer 30 is used to mix the waste liquid and waste residue generated by the 3-hydroxypropionic acid purification unit and the acrylic acid production unit. The anaerobic fermentation tank 31 is used to ferment the mixture in the second mixer 30 into biogas and nitrogen-containing sludge. The third flash tank 32 is used to separate biogas and nitrogen-containing sludge. A biogas outlet and a nitrogen-containing sludge outlet are provided on the body of the third flash tank 32. The nitrogen-containing sludge outlet of the third flash tank 32 is connected to a centrifuge 38. The centrifuge 38 is used to centrifugally dehydrate the nitrogen-containing sludge and output the process by-product nitrogen fertilizer; the biogas outlet of the third flash tank 32 is connected to the inlet of the third mixer 33. The third mixer 33 is used to mix the biogas separated by the third flash tank 32 and the waste gas generated by the biological fermentation acetic acid production unit and the biological fermentation 3-hydroxypropionic acid production unit. The outlet of the third mixer 33 and the third compressor 35 are connected to the combustion chamber 34 respectively, and the mixed gas in the third mixer 33 and the compressed air from the third compressor 35 are mixed and burned in the combustion chamber 34. The gas turbine 36 can generate electricity using the high-temperature gas after combustion in the combustion chamber 34, and at the same time use the obtained high-temperature waste heat to provide heat for the bio-fermentation acetic acid production unit, the bio-fermentation 3-hydroxypropionic acid production unit, the 3-hydroxypropionic acid purification unit and the acrylic acid production unit. The seventh heat exchanger 37 is used to cool the remaining high-temperature gas generated by the gas turbine 36 for power generation.

[0042] In the entire system, the arrangement of the first compressor 1, the first pump 4, the second pump 9, the third pump 12, the fourth pump 17, the second compressor 19, the fifth pump 25 and the third compressor 35 can provide power for the operation of the entire system by pressurizing the gas or liquid.

[0043] A method for preparing acrylic acid using the above system specifically comprises: (1) Bio-fermentation acetic acid production unit: The steel mill tail gas is pressurized to 3 bar in the first compressor 1, and then the temperature is controlled at 60°C through the first heat exchanger 2. Sodium hydroxide solution is used as a buffer to adjust the pH value in the fermentation tank so that the fermentation condition is maintained at a pH of about 6.0-6.5. Ammonia is used as a nutrient for the biological fermentation. After the sodium hydroxide solution and ammonia are mixed in the first storage tank 3, they are pressurized to 3 bar by the first pump 4, and the temperature is controlled at 30°C by the second heat exchanger 5. After that, the steel mill tail gas in the first heat exchanger 2 and the sodium hydroxide solution and ammonia in the second heat exchanger 5 are mixed by the first mixer 6 and enter the first fermentation tank 7. With the participation of Moore's bacteria, the steel mill tail gas is fermented at 60°C and 1 bar. The carbon monoxide in the steel mill tail gas is converted into acetic acid and biomass to form a fermentation liquid containing acetic acid and biomass. Afterwards, the fermentation liquid containing acetic acid and biomass and the remaining waste gas are separated in the first flash tank 8 , the separated fermentation liquid containing acetic acid and biomass enters the second pump 9 , and the separated waste gas enters the third mixer 33 .

[0044] (2) Bio-fermentation unit for producing 3-hydroxypropionic acid: The fermentation liquid containing acetic acid and biomass is pressurized to 3 bar in the second pump 9, and then the temperature is controlled at 37°C by the third heat exchanger 10. Sodium hydroxide solution is used as a buffer to adjust the pH value in the second fermentation tank 14 so that the fermentation condition is maintained at a pH of about 6.0-6.5; ammonia is used as a nutrient for the bio-fermentation. After the sodium hydroxide solution and ammonia are mixed in the second storage tank 11, they are pressurized to 3 bar by the third pump 12, and then the temperature is controlled to 37°C by the fourth heat exchanger 13. The fermentation liquid containing acetic acid and biomass in the third heat exchanger 10 and the sodium hydroxide solution and ammonia in the fourth heat exchanger 13 enter the second fermentation tank 14, and bio-fermentation is carried out at 37°C and 1 bar with the participation of Vibrio natrii, so that acetic acid is converted into 3-hydroxypropionic acid and biomass, and a fermentation liquid containing 3-hydroxypropionic acid and biomass is obtained. The fermentation liquid containing 3-hydroxypropionic acid and biomass and the remaining waste gas are separated in the second flash tank 15 , the separated fermentation liquid containing 3-hydroxypropionic acid and biomass enters the third storage tank 16 , and the separated waste gas enters the third mixer 33 .

[0045] (3) 3-hydroxypropionic acid purification unit: The fermentation liquid containing 3-hydroxypropionic acid and biomass is pressurized to 3 bar in the fourth pump 17 and then enters the dissolved air flotation reactor 18. At the same time, the air is pressurized to 3 bar by the second compressor 19, and after heat exchange to 25°C by the fifth heat exchanger 20, it enters the dissolved air flotation reactor 18 through the air storage 21. At the same time, 100 mg / L flocculant is added to the dissolved air flotation reactor 18 to assist in removing waste residue. In the dissolved air flotation reactor 18, the compressed air introduced generates tiny bubbles in the fermentation liquid containing 3-hydroxypropionic acid and biomass, thereby separating the fermentation liquid containing 3-hydroxypropionic acid and biomass from the waste residue to obtain the fermentation liquid containing 3-hydroxypropionic acid; under the action of the flocculant, the removal efficiency of the waste residue in the fermentation liquid can reach more than 95%. The fermentation liquid containing 3-hydroxypropionic acid after separation enters the distillation tower 22, and 3-hydroxypropionic acid in the fermentation liquid containing 3-hydroxypropionic acid is extracted by 1-hexanol to obtain a mixed solution containing 3-hydroxypropionic acid and an extractant. The mixed solution containing 3-hydroxypropionic acid and an extractant is further separated in the separator 23, and the waste liquid separated by the separator 23 enters the second mixer 30 for subsequent treatment; the mixed solution containing 3-hydroxypropionic acid separated by the separator 23 enters the first vacuum distillation tower 24 for distillation. High-purity 3-hydroxypropionic acid flows out of the tower bottom outlet of the first vacuum distillation tower 24, and the high-purity 3-hydroxypropionic acid is pressurized to 3 bar by the fifth pump 25, and heated to 230°C by the fourth heat exchanger 26, and the overall extraction efficiency is about 91%; the 1-hexanol separated by the first vacuum distillation tower 24 flows out from the top of the first vacuum distillation tower 24, enters the extractive distillation tower 22, and is reused.

[0046] (4) Acrylic acid production unit: High-purity 3-hydroxypropionic acid is dehydrated in the dehydration reactor 27 at 230°C and 1 bar to produce crude acrylic acid with a conversion rate of about 80% to 90%. Crude acrylic acid and incompletely dehydrated 3-hydroxypropionic acid are separated in the second vacuum distillation tower 28. Incompletely dehydrated 3-hydroxypropionic acid flows out from the bottom of the second vacuum distillation tower 28 and refluxes to the dehydration reactor 27 for reuse. Crude acrylic acid is separated in the third vacuum distillation tower 29 to produce acrylic acid with a purity of 99 wt% to 99.8 wt%. During the distillation process, waste liquid flows out from the top of the third vacuum distillation tower 29 and enters the second mixer 30.

[0047] (5) Cogeneration unit: The waste liquid and waste residue generated in the whole process enter the anaerobic fermentation tank 31 through the second mixer 30, and produce biogas and nitrogen-containing sludge through anaerobic fermentation at 35°C and 1 bar. After that, the biogas and nitrogen-containing sludge are separated in the third flash tank 32. The biogas separated in the third flash tank 32 is mixed with the waste gas separated from the first flash tank 8 and the second flash tank 15 in the third mixer 33 and then enters the combustion chamber 34. At the same time, the air from the third compressor 35 is compressed to 3 bar and then enters the combustion chamber 34. Waste gases such as methane and hydrogen are burned with oxygen in the combustion chamber 34 at 1600°C. A large amount of high-temperature waste heat is generated during the combustion process, and electricity is generated through the gas turbine 36. At the same time, the high-temperature waste heat is obtained and used to provide heat for the bio-fermentation acetic acid production unit, the bio-fermentation 3-hydroxypropionic acid production unit, the 3-hydroxypropionic acid purification unit and the acrylic acid production unit through heat exchange equipment. The high temperature gas generated by the gas turbine 36 is cooled by the seventh heat exchanger 37 to obtain cooling gas, which is discharged as process tail gas. The nitrogen-containing sludge separated in the third flash tank 32 is centrifuged by the centrifuge 38 to become a process byproduct nitrogen fertilizer with a moisture content of about 50% to 60%, which is used for agricultural production.

[0048] By constructing a process simulation for preparing acrylic acid through bio-fermentation using synthesis gas from steel plant exhaust gas, analyzing the energy flow and material flow, as well as the connection and coupling of each component unit, the corresponding key operating parameters were determined, and a technical route for preparing acrylic acid directly from waste gas containing carbon monoxide through two-stage bio-fermentation technology was provided. This process can not only reduce the dependence on fossil-based products in the process of social development, but also realize the preparation of high value-added products from greenhouse gases.

[0049] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A system for preparing acrylic acid using waste gas containing carbon monoxide, characterized in that: It includes a biological fermentation acetic acid production unit, a biological fermentation 3-hydroxypropionic acid production unit, a 3-hydroxypropionic acid purification unit and an acrylic acid production unit connected in sequence; The bio-fermentation acetic acid production unit is used to carry out bio-fermentation using carbon monoxide in the exhaust gas as a substrate to obtain a fermentation liquid containing acetic acid; The biological fermentation unit for producing 3-hydroxypropionic acid is used for biological fermentation with acetic acid as a substrate to obtain a fermentation liquid containing 3-hydroxypropionic acid; A 3-hydroxypropionic acid purification unit, used for separating and extracting the fermentation broth containing 3-hydroxypropionic acid to obtain 3-hydroxypropionic acid; Acrylic acid production unit, used to dehydrate 3-hydroxypropionic acid to produce acrylic acid.

2. A system for preparing acrylic acid using waste gas containing carbon monoxide according to claim 1, characterized in that: It also includes a cogeneration unit, which is respectively connected to the bio-fermentation acetic acid production unit, the bio-fermentation 3-hydroxypropionic acid production unit, the 3-hydroxypropionic acid purification unit and the acrylic acid production unit. The cogeneration unit is used to convert the waste generated in the production process into electricity, heat energy and nitrogen-containing sludge.

3. A system for preparing acrylic acid using waste gas containing carbon monoxide according to claim 2, characterized in that: The cogeneration unit comprises a second mixer (30), an anaerobic fermentation tank (31), a third flash tank (32), a third mixer (33), a combustion chamber (34), a gas turbine (36) and a seventh heat exchanger (37) which are connected in sequence. The second mixer (30) is used to treat waste liquid and waste residue generated by the acrylic acid production unit and the 3-hydroxypropionic acid purification unit. The third mixer (33) is used to treat waste gas generated by the third flash tank (32), the biological fermentation acetic acid production unit and the biological fermentation 3-hydroxypropionic acid production unit.

4. A system for preparing acrylic acid by using waste gas containing carbon monoxide according to claim 3, characterized in that: The invention also includes a third compressor (35) and a centrifuge (38). The third compressor (35) is connected to the combustion chamber (34) and is used to input compressed air into the combustion chamber (34). The centrifuge (38) is connected to the third flash tank (32) and is used to centrifuge the nitrogen-containing sludge produced by fermentation in the third flash tank (32) to form nitrogen fertilizer.

5. A system for preparing acrylic acid using waste gas containing carbon monoxide according to any one of claims 1 to 4, characterized in that: The biological fermentation acetic acid production unit comprises a first compressor (1), a first heat exchanger (2), a first mixer (6), a first fermentation tank (7) and a first flash tank (8) which are connected in sequence, the first fermentation tank (7) being inoculated with Moorella, and the first flash tank (8) being connected to the biological fermentation 3-hydroxypropionic acid production unit.

6. A system for preparing acrylic acid by using waste gas containing carbon monoxide according to claim 5, characterized in that: The biological fermentation acetic acid production unit further comprises a first storage tank (3), a first pump (4) and a second heat exchanger (5) which are connected in sequence, and the second heat exchanger (5) is connected to the first mixer (6).

7. A system for preparing acrylic acid using waste gas containing carbon monoxide according to any one of claims 1 to 4, characterized in that: The biological fermentation unit for producing 3-hydroxypropionic acid comprises a second pump (9), a third heat exchanger (10), a second fermentation tank (14) and a second flash tank (15) which are connected in sequence. The second fermentation tank (14) is inoculated with Vibrio natrii. The second pump (9) is connected to the biological fermentation unit for producing acetic acid, and the second flash tank (15) is connected to the 3-hydroxypropionic acid purification unit.

8. A system for preparing acrylic acid using waste gas containing carbon monoxide according to any one of claims 1 to 4, characterized in that: The 3-hydroxypropionic acid purification unit comprises a third storage tank (16), a fourth pump (17), a dissolved air flotation reactor (18), an extractive distillation tower (22), a separator (23), a first vacuum distillation tower (24), a fifth pump (25) and a sixth heat exchanger (26) which are connected in sequence. The third storage tank (16) is connected to the biological fermentation unit for producing 3-hydroxypropionic acid, and the sixth heat exchanger (26) is connected to the acrylic acid production unit.

9. A system for preparing acrylic acid using waste gas containing carbon monoxide according to any one of claims 1 to 4, characterized in that: The acrylic acid production unit comprises a dehydration reactor (27), a second vacuum distillation tower (28) and a third vacuum distillation tower (29) which are connected in sequence, and the dehydration reactor (27) is connected to a 3-hydroxypropionic acid purification unit.

10. A method for preparing acrylic acid using waste gas containing carbon monoxide, characterized in that: The carbon monoxide in the waste gas is used for biological fermentation to obtain acetic acid; the acetic acid is used for biological fermentation to obtain 3-hydroxypropionic acid, which is separated, extracted and dehydrated to obtain acrylic acid.

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