System and method for preparing ethylene glycol from biomass

Abstract

The invention discloses a system and a method for preparing ethylene glycol from biomass. The system for preparing the ethylene glycol from the biomass comprises an electrolytic hydrogen production device and a device for preparing the ethylene glycol from the biomass, the device for preparing ethylene glycol from biomass comprises a waste heat recovery unit, a gas separation unit, a dimethyl oxalate synthesis unit and an ethylene glycol synthesis unit, a carbon monoxide outlet of the gas separation unit is connected with the dimethyl oxalate synthesis unit; a hydrogen outlet of the gas separation unit is connected with the ethylene glycol synthesis unit; an electrolytic cell of the electrolytic hydrogen production device is connected with a high-temperature water vapor outlet of the waste heat recovery unit; an oxygen outlet of the electrolytic hydrogen production device is connected with the dimethyl oxalate synthesis unit; a hydrogen outlet of the electrolytic hydrogen production device is connected with the ethylene glycol synthesis unit; according to the invention, the electrolytic hydrogen production device and the biomass ethylene glycol production device are organically coupled, and products or by-products of each other are used as production raw materials of each other, so that the overall efficiency improvement and emission reduction of the equipment are realized.

Description

Technical Field

[0001] The invention relates to the technical field of ethylene glycol preparation, and in particular to a system and method for preparing ethylene glycol from biomass. Background Art

[0002] As an important organic chemical raw material and green solvent, ethylene glycol is widely used in the production of polyester fibers, polyester resins, antifreeze and pharmaceuticals.

[0003] In order to alleviate energy shortages and reduce carbon emissions, my country is vigorously developing renewable energy. Biomass is a renewable energy with great potential. The use of biomass synthesis gas to prepare ethylene glycol has the advantages of abundant raw material resources, energy conservation and emission reduction, and green and low-carbon.

[0004] The inventors have found through research that the preparation of ethylene glycol in the prior art still has at least the following defects:

[0005] In the existing biomass to ethylene glycol process, a large amount of carbon dioxide is produced, thus causing carbon emission pollution.

[0006] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0007] The purpose of the present invention is to reduce carbon emissions in the process of preparing ethylene glycol from biomass.

[0008] The present invention provides a biomass to ethylene glycol system, comprising: an electrolytic hydrogen production device and a biomass to ethylene glycol device;

[0009] The biomass-to-ethylene glycol device comprises a waste heat recovery unit, a gas separation unit, a dimethyl oxalate synthesis unit and an ethylene glycol synthesis unit; wherein,

[0010] The carbon monoxide outlet of the gas separation unit is connected to the dimethyl oxalate synthesis unit; the hydrogen outlet of the gas separation unit is connected to the ethylene glycol synthesis unit;

[0011] The electrolytic cell of the electrolytic hydrogen production device is connected to the high-temperature water vapor outlet of the waste heat recovery unit; the oxygen outlet of the electrolytic hydrogen production device is connected to the dimethyl oxalate synthesis unit; and the hydrogen outlet of the electrolytic hydrogen production device is connected to the ethylene glycol synthesis unit.

[0012] Preferably, in the embodiment of the present invention, it also includes:

[0013] A carbon monoxide storage unit is connected to the carbon monoxide outlet of the gas separation unit.

[0014] Preferably, in an embodiment of the present invention, the electrolysis hydrogen production device comprises:

[0015] Wind and / or solar power generation units, batteries, electrolyzers, hydrogen storage tanks and oxygen storage tanks.

[0016] Preferably, in an embodiment of the present invention, the biomass to ethylene glycol device comprises:

[0017] pretreatment unit, gasifier unit, acid gas removal unit and glycol refining unit;

[0018] The pretreatment unit transports the crushed biomass to the gasification furnace unit;

[0019] The waste residue outlet of the gasifier unit is connected to the waste heat recovery unit, and the synthesis gas outlet of the gasifier unit is connected to the acid gas removal unit;

[0020] The ethylene glycol refining unit is connected to the ethylene glycol synthesis unit.

[0021] Preferably, in the embodiment of the present invention, the oxygen output pipeline of the electrolytic hydrogen production device also includes an output branch connected to the gasifier unit.

[0022] Preferably, in the embodiment of the present invention, it also includes:

[0023] A carbon dioxide recycling pipeline between the carbon dioxide outlet of the acid gas removal unit and the gasifier unit.

[0024] Preferably, in an embodiment of the present invention, the dimethyl oxalate synthesis unit comprises:

[0025] A carbonylation mechanism for preparing dimethyl oxalate using carbon monoxide and methyl nitrite, and,

[0026] Mechanism for regenerating methyl nitrite using nitric oxide and methanol to prepare methyl nitrite.

[0027] Preferably, in an embodiment of the present invention, the methyl nitrite regeneration mechanism is connected to the methanol outlet of the ethylene glycol refining unit.

[0028] Preferably, in an embodiment of the present invention, the electrolytic cell is connected to the steam generator of the waste heat recovery unit.

[0029] Preferably, in an embodiment of the present invention, a hydrogen purification mechanism is further provided between the electrolyzer and the hydrogen storage tank.

[0030] Preferably, in an embodiment of the present invention, the hydrogen purification mechanism comprises: a hydrogen pressure swing adsorption purification module.

[0031] In another aspect of the present invention, a biomass-to-ethylene glycol method is also provided, which is used in the biomass-to-ethylene glycol system as described above, comprising:

[0032] The electrolytic hydrogen production device receives the high-temperature steam generated by the waste heat recovery unit as an electrolytic raw material to generate oxygen and hydrogen;

[0033] The dimethyl oxalate synthesis unit obtains the oxygen generated by the electrolytic hydrogen production device and the carbon monoxide generated by the gas separation unit to generate dimethyl oxalate;

[0034] The ethylene glycol synthesis unit obtains the dimethyl oxalate, the hydrogen generated by the electrolytic hydrogen production device and the hydrogen generated by the gas separation unit to generate ethylene glycol.

[0035] Preferably, in the embodiment of the present invention, it also includes:

[0036] When the carbon monoxide generated by the gas separation unit meets the requirement for generating dimethyl oxalate, the remaining carbon monoxide is stored in a preset carbon monoxide storage unit.

[0037] Preferably, in the embodiment of the present invention, it also includes:

[0038] When the oxygen generated by the electrolytic hydrogen production device meets the requirement for generating dimethyl oxalate, the remaining oxygen is used as the oxygen supply for the gasifier unit.

[0039] Preferably, in the embodiment of the present invention, it also includes:

[0040] The carbon dioxide generated by the acid gas removal unit is transported to the gasifier unit.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The present invention organically couples an electrolytic hydrogen production device and a biomass ethylene glycol production device, and utilizes each other's products or by-products as their own production raw materials, thereby achieving overall efficiency improvement and emission reduction of the equipment. Specifically, the electrolytic hydrogen production device of the present invention utilizes high-temperature steam prepared by high-temperature waste heat of a gasifier as a raw material to prepare hydrogen and oxygen; and the ethylene glycol synthesis unit and the dimethyl oxalate synthesis unit of the gasifier respectively use the hydrogen and oxygen generated by the electrolytic hydrogen production device as raw materials to prepare ethylene glycol.

[0043] As can be seen from the above, in the present invention, on the one hand, the electrolytic hydrogen production device uses high-temperature water vapor prepared by the high-temperature waste heat of the gasifier as a raw material to prepare hydrogen and oxygen, thereby realizing the effective utilization of the byproduct (waste heat) that is difficult to utilize in the gasifier, so as to improve the preparation efficiency of hydrogen and oxygen; on the other hand, since the present invention can supplement the hydrogen-carbon ratio required for the preparation of ethylene glycol by the hydrogen generated by the electrolytic hydrogen production device, there is no need to use the carbon monoxide generated by the separation unit to produce hydrogen to supplement the hydrogen-carbon ratio as in the prior art, thus avoiding the carbon dioxide generated in the process of hydrogen production from carbon monoxide. In this way, the utilization value of carbon monoxide is improved, and the problem of carbon emission pollution caused by the use of carbon monoxide to produce hydrogen and the generation of carbon dioxide in the prior art is solved. In addition, since the cost of hydrogen production by electrolysis in the present invention is lower than the cost of preparing hydrogen using carbon monoxide, the overall operating cost of the equipment can also be effectively reduced through the present invention.

[0044] Furthermore, in the present invention, the carbon monoxide outlet of the gas separation unit can also be connected to a carbon monoxide storage unit. In this way, when the carbon monoxide generated by the gas separation unit is sufficient to generate dimethyl oxalate and there is still a surplus, the carbon monoxide with economic value can be stored in the carbon monoxide storage unit. In this way, the overall economic benefits of the equipment are improved while maintaining negative carbon emissions.

[0045] Furthermore, in the present invention, the carbon dioxide generated by the acid gas removal unit can be fed back to the gasifier unit to be used for generating syngas, which can further reduce the overall carbon emissions of the equipment.

[0046] Furthermore, in the present invention, the oxygen output pipeline of the electrolytic hydrogen production device can also be connected to the gasifier unit. In this way, when the oxygen generated by the electrolytic hydrogen production device is sufficient to meet the needs of generating dimethyl oxalate and there is a surplus, it can be used to supplement the oxygen demand of the gasifier unit, thereby improving the efficiency of the gasifier unit in preparing synthesis gas.

[0047] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, and to make the above and other purposes, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1 It is a structural schematic diagram of the biomass to ethylene glycol system of the present invention;

[0050] Figure 2 It is a structural schematic diagram of the electrolyte hydrogen device of the present invention;

[0051] Figure 3 It is a schematic flow diagram of the method for preparing ethylene glycol from biomass described in the present invention. DETAILED DESCRIPTION

[0052] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0053] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0054] In this document, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to limit a specific position or relative relationship. In other words, in some embodiments, the terms "first", "second", etc. can also be interchangeable.

[0055] Embodiment 1

[0056] In order to prepare ethylene glycol in an environmentally friendly and low-carbon manner, refer to Figure 1 and Figure 2 , an embodiment of the present invention provides a biomass to ethylene glycol system, including: an electrolytic hydrogen production device 100 and a biomass to ethylene glycol device 200;

[0057] The biomass to ethylene glycol device 100 includes a waste heat recovery unit, a gas separation unit, a dimethyl oxalate synthesis unit and an ethylene glycol synthesis unit; wherein the carbon monoxide outlet of the gas separation unit is connected to the dimethyl oxalate synthesis unit; the hydrogen outlet of the gas separation unit is connected to the ethylene glycol synthesis unit; the electrolytic cell of the electrolytic hydrogen production device is connected to the high-temperature water vapor outlet of the waste heat recovery unit; the oxygen outlet of the electrolytic hydrogen production device is connected to the dimethyl oxalate synthesis unit; and the hydrogen outlet of the electrolytic hydrogen production device is connected to the ethylene glycol synthesis unit.

[0058] A certain hydrogen-to-carbon ratio is required in the preparation process of ethylene glycol. The hydrogen separated from the synthesis gas is insufficient to meet the requirement of the hydrogen-to-carbon ratio. The inventors have found through research that most of the existing technologies use carbon monoxide to produce hydrogen to make up for the amount of hydrogen required for the hydrogen-to-carbon ratio. This not only causes a waste of carbon monoxide, but also produces carbon dioxide and thus causes carbon emission pollution. In order to solve the above technical problems, a biomass-to-ethylene glycol system is provided in an embodiment of the present invention.

[0059] In the embodiment of the present invention, the high-temperature waste heat generated by the gasification furnace unit is used to prepare high-temperature water vapor through the waste heat recovery unit, so that the electrolytic hydrogen production device 100 can use high-temperature water vapor as the electrolysis raw material to generate hydrogen and oxygen; the hydrogen generated by the electrolytic hydrogen production device 100 can be used to prepare ethylene glycol, so there is no need to use the carbon monoxide generated by the gas separation unit to produce hydrogen to make up the hydrogen-carbon ratio; in the embodiment of the present invention, the carbon monoxide generated by the gas separation unit is used to meet the needs of generating dimethyl oxalate, and no longer needs to be used to prepare hydrogen, which improves the utilization value of carbon monoxide, and further solves the problem of carbon emission pollution caused by using carbon monoxide to produce hydrogen in the prior art. In addition, since the cost of electrolytic hydrogen production in the embodiment of the present invention is lower than the cost of using carbon monoxide to prepare hydrogen, the overall operating cost of the equipment can be effectively reduced through the embodiment of the present invention.

[0060] Furthermore, in an embodiment of the present invention, the carbon monoxide outlet of the gas separation unit is connected to a carbon monoxide storage unit. Thus, when the carbon monoxide generated by the gas separation unit is sufficient to generate dimethyl oxalate and there is a surplus, the carbon monoxide with economic value can be stored in the carbon monoxide storage unit. In this way, the overall economic benefits of the equipment are improved while achieving negative carbon emissions.

[0061] Furthermore, in an embodiment of the present invention, the oxygen output pipeline of the electrolytic hydrogen production device 100 can also be connected to the gasifier unit. In this way, when the oxygen generated by the electrolytic hydrogen production device 100 is sufficient to meet the needs of generating dimethyl oxalate and there is a surplus, it can be used to supplement the oxygen demand of the gasifier unit, thereby improving the efficiency of the gasifier unit in preparing synthesis gas.

[0062] In the embodiment of the present invention, the process of the biomass-to-ethylene glycol system formed by coupling the electrolytic hydrogen production device 100 and the biomass-to-ethylene glycol device 200 can be specifically as follows:

[0063] Biomass (such as corn stalks) is crushed and dried in a pretreatment unit to generate crushed biomass, which then enters a gasifier unit for gasification to generate a crude synthesis gas rich in carbon monoxide, carbon dioxide and hydrogen; the waste residue in the gasifier unit enters the steam reaction chamber of the waste heat recovery unit through the waste residue outlet, and the high-temperature water vapor generated in the steam reaction chamber is sent to the electrolytic cell of the electrolytic hydrogen production device 100 as an electrolytic raw material for electrolyzing hydrogen and oxygen; the crude synthesis gas passes through an acid gas removal unit to separate part of the carbon dioxide and return it to the gasifier unit as a crude The gas raw material of synthesis gas; the deacidified synthesis gas mainly composed of carbon monoxide and hydrogen is passed through a gas separation unit to generate high-purity hydrogen and carbon monoxide; after the carbon monoxide enters the dimethyl oxalate synthesis unit, it reacts with the oxygen generated by the electrolytic hydrogen production device 100 as a raw material to generate dimethyl oxalate; the dimethyl oxalate entering the ethylene glycol synthesis unit, reacts with the hydrogen generated by the electrolytic hydrogen production device 100 and the hydrogen generated by the gas separation unit as raw materials to generate crude ethylene glycol; the crude ethylene glycol is passed through an ethylene glycol refining unit to generate high-purity ethylene glycol.

[0064] Furthermore, in the embodiment of the present invention, the oxygen generated by the electrolytic cell of the electrolytic hydrogen production device 100 after satisfying the requirement for generating dimethyl oxalate can also be used as the oxygen supply for the gasifier unit.

[0065] Furthermore, in the embodiment of the present invention, part of the carbon dioxide generated by the acid gas removal unit can also be used as a gas raw material for the gasifier unit to reduce the overall carbon emission of the equipment.

[0066] Furthermore, in an embodiment of the present invention, the carbon dioxide outlet of the acid gas removal unit is connected to the gasifier unit, so that part of the carbon dioxide removed by the acid gas removal unit can also be used as a raw material for the gasifier unit as a synthesis gas, which further reduces carbon emissions, ensures environmental protection, and solves the problem of environmental pollution caused by carbon dioxide emissions. It should be noted that in order to improve the acid gas removal effect of the synthesis gas, the method used in the acid gas removal unit can include at least one of the low-temperature methanol washing technology and the polyethylene glycol dimethyl ether technology.

[0067] Furthermore, in an embodiment of the present invention, the dimethyl oxalate synthesis unit may include: a carbonylation mechanism for preparing dimethyl oxalate from carbon monoxide and methyl nitrite; a methyl nitrite regeneration mechanism for preparing methyl nitrite from nitric oxide and methanol; the methyl nitrite regeneration mechanism is connected to the methanol outlet of the ethylene glycol refining unit, so that the by-product methanol produced by the ethylene glycol refining unit can be used in the methyl nitrite regeneration mechanism, together with nitric oxide as a raw material, to prepare methyl nitrite.

[0068] In practical applications, such as Figure 1As shown, the biomass to ethylene glycol device 200 in the embodiment of the present invention may include: a pretreatment unit, a gasifier unit, a waste heat recovery unit, an acid gas removal unit, a gas separation unit, an ethylene glycol synthesis unit, a dimethyl oxalate synthesis unit and an ethylene glycol refining unit, wherein:

[0069] The gasification raw material inlet of the gasifier unit is connected to the crushed biomass outlet of the pretreatment unit; the oxygen inlet of the gasifier unit is connected to the oxygen outlet of the electrolytic hydrogen production device; the waste residue outlet of the gasifier unit is connected to the waste heat recovery unit, and the synthesis gas outlet of the gasifier unit is connected to the acid gas removal unit.

[0070] The electrolysis process of water vapor can produce high-purity hydrogen with low electricity consumption, but it requires additional heat energy to produce water vapor. In the embodiment of the present invention, the waste slag outlet of the gasifier unit is connected to the waste heat recovery unit, so that the waste slag produced by the gasifier unit can flow into the waste heat recovery unit, thereby generating high-temperature water vapor for electrolytic hydrogen production through the heat of the waste slag. This realizes the effective utilization of the by-products (waste heat) of the gasifier that are difficult to utilize, thereby improving the production efficiency of hydrogen and oxygen.

[0071] Further, in an embodiment of the present invention, if Figure 2 As shown, the electrolysis hydrogen production device 100 may include: a wind energy and / or solar energy power generation unit, a battery, an electrolyzer, a hydrogen storage tank and an oxygen storage tank; the hydrogen storage tank and the oxygen storage tank are respectively connected to the electrolyzer for storing hydrogen and oxygen produced by electrolysis.

[0072] In practical applications, the electrolyzer can be connected to the steam generator of the waste heat recovery unit, so that the electrolysis hydrogen production device 100 can use the high-temperature water vapor therein to electrolyze water to produce hydrogen.

[0073] The electrolytic cell in the embodiment of the present invention can be a high-temperature solid oxide electrolytic cell, the electrolysis temperature can be set to 600-1000°C, the cathode material can be Ni / YSZ porous metal ceramic, the anode material is doped lanthanum manganate, the electrolyte can be YSZ oxygen ion conductor, and high-temperature solid oxide electrolysis is used to generate hydrogen and oxygen, and then the hydrogen enters the hydrogen storage tank to smooth the fluctuation after cooling, washing, deoxidation and drying; the oxygen enters the oxygen storage tank to smooth the fluctuation after cooling, washing, deoxidation and drying. In addition, the oxygen generated by electrolysis of the electrolytic hydrogen production device 100 can be used as auxiliary oxygen supply when the gasifier unit generates synthesis gas when there is a surplus in the supply of the dimethyl oxalate unit.

[0074] In an embodiment of the present invention, a hydrogen purification mechanism, such as a hydrogen pressure swing adsorption purification module, may be provided between the electrolyzer and the hydrogen storage tank, which can also provide high-purity hydrogen for the preparation of ethylene glycol.

[0075] The power generation unit in the embodiment of the present invention can use one of wind energy and solar energy, and can also be set to generate electricity with wind energy and solar energy at the same time. The generated electric energy is adjusted to direct current with a voltage required for battery storage and electrolytic cell operation after being transformed and rectified by the inverter; and then supplied to the electrolytic cell unit to electrolyze water to produce oxygen and hydrogen after the fluctuation is smoothed by the battery. In the implementation of the present invention, by making full use of the abundant reserves of wind energy and solar energy, not only the local utilization of multiple energy sources is realized, but also the problem of wind and solar abandonment can be solved.

[0076] In addition, in an embodiment of the present invention, the ethylene glycol refining unit is connected to the ethylene glycol synthesis unit, and the ethylene glycol refining unit is used to purify the crude ethylene glycol generated by the ethylene glycol synthesis unit to obtain refined ethylene glycol.

[0077] In practical applications, the ethylene glycol synthesis unit in the embodiment of the present invention may specifically include: an ethylene glycol synthesis reactor and a purification tower; the ethylene glycol refining unit may specifically include: a methanol recovery tower, a dehydration tower, a dealcoholization tower, an ethylene glycol product tower and an ethylene glycol recovery tower; in the ethylene glycol synthesis unit, the molar ratio of hydrogen to dimethyl oxalate is between 35-45, thereby obtaining a higher yield of crude ethylene glycol.

[0078] In the embodiment of the present invention, when biomass is used to prepare ethylene glycol, the biomass may include one or more of crop straw, forest products, marine plants and urban biomass waste (such as paper recycling and natural fibers). The embodiment of the present invention can effectively alleviate the problem of energy shortage by using renewable resources as raw materials to prepare ethylene glycol.

[0079] The following is a description of the use of the biomass to ethylene glycol system in the embodiment of the present invention with reference to a number of examples.

[0080] Example 1:

[0081] 1. 14 wind turbines are used to generate electricity, with a rated power of 5MW for each wind turbine; the battery capacity is 600MWh; there are 15 electrolyzers, with a rated power of 2MW for each electrolyzer; the temperature of the ethylene glycol synthesis unit is controlled at 230°C and the pressure is controlled at 3.0MPa; corn stalks are used as biomass, and the feed rate of the gasifier unit is 20 tons per hour;

[0082] 2. The wind turbine generates AC power, which is transformed and rectified by the inverter to be adjusted to DC power that meets the voltage required for battery storage and electrolytic cell operation. After the DC power is smoothed by the battery, it enters the high-temperature solid oxide electrolytic cell to electrolyze water to produce hydrogen and oxygen. The hydrogen and oxygen are further smoothed by the hydrogen storage tank and the oxygen storage tank respectively.

[0083] 3. The oxygen, water, crushed biomass and carbon dioxide entering the gasifier are gasified to generate a crude synthesis gas rich in carbon monoxide, carbon dioxide and hydrogen;

[0084] 4. The crude synthesis gas is separated from acid gases such as carbon dioxide by acid gas removal and supplied to the gasifier; deacidified synthesis gas mainly composed of carbon monoxide and hydrogen is generated; the deacidified synthesis gas is passed through a gas separation unit to generate high-purity hydrogen and carbon monoxide;

[0085] 5. After carbon monoxide enters the dimethyl oxalate synthesis unit, it reacts with oxygen as a raw material to generate dimethyl oxalate; the dimethyl oxalate entering the ethylene glycol synthesis unit reacts with the hydrogen in the electrolyzer and the hydrogen generated by the gas separation unit as raw materials to generate crude ethylene glycol; the crude ethylene glycol is converted into high-purity ethylene glycol through the ethylene glycol refining unit.

[0086] The output of ethylene glycol produced in this way is 13 tons per hour.

[0087] Example 2:

[0088] 1. The photovoltaic array is composed of solar photovoltaic panels, with a total rated power of 100MW and a photoelectric conversion rate of 23%. The battery capacity is 850MWh. There are 21 electrolyzers, with a single electrolyzer rated power of 2MW. The temperature of the ethylene glycol synthesis unit is controlled at 235℃ and the pressure is controlled at 3.2Mpa. The biomass is rice straw, and the feed rate of the gasifier unit is 28 tons per hour.

[0089] 2. The electric energy generated by the solar photovoltaic panel is transformed and rectified by the inverter and adjusted to the DC power that meets the voltage required for battery storage and electrolytic cell operation. After the DC power is smoothed by the battery, it enters the high-temperature solid oxide electrolytic cell to electrolyze water to produce hydrogen and oxygen. The hydrogen and oxygen are further smoothed by the hydrogen storage tank and oxygen storage tank respectively.

[0090] 3. The oxygen, water, crushed biomass and carbon dioxide entering the gasifier are gasified to generate a crude synthesis gas rich in carbon monoxide, carbon dioxide and hydrogen;

[0091] 4. The crude synthesis gas is separated from acid gases such as carbon dioxide by acid gas removal and supplied to the gasifier; deacidified synthesis gas mainly composed of carbon monoxide and hydrogen is generated; the deacidified synthesis gas is passed through a gas separation unit to generate high-purity hydrogen and carbon monoxide;

[0092] 5. After carbon monoxide enters the dimethyl oxalate synthesis unit, it reacts with oxygen as a raw material to generate dimethyl oxalate; the dimethyl oxalate entering the ethylene glycol synthesis unit reacts with the hydrogen in the electrolyzer and the hydrogen generated by the gas separation unit as raw materials to generate crude ethylene glycol; the crude ethylene glycol is converted into high-purity ethylene glycol through the ethylene glycol refining unit.

[0093] The output of ethylene glycol produced in this way is 18 tons per hour.

[0094] Example 3:

[0095] 1. The photovoltaic array is composed of solar photovoltaic panels, with a total rated power of 100MW and a photoelectric conversion rate of 23%. 20 wind turbines are used to generate electricity, with a rated power of 5MW per wind turbine. The capacity of the battery is 1600MWh. There are 21 electrolyzers, with a rated power of 2MW per electrolyzer. The temperature of the ethylene glycol synthesis unit is controlled at 225℃ and the pressure is controlled at 2.8Mpa. The biomass is Hongsen Sophora japonica, and the feed rate of the gasifier unit is 60 tons per hour.

[0096] 2. The electric energy generated by wind turbines and solar photovoltaic panels is transformed and rectified by the inverter and adjusted to direct current that meets the voltage required for battery storage and electrolyzer operation. After the direct current is smoothed by the battery, it enters the high-temperature solid oxide electrolyzer to electrolyze water to produce hydrogen and oxygen. The hydrogen and oxygen are further smoothed by hydrogen storage tanks and oxygen storage tanks respectively.

[0097] 3. The oxygen, water, crushed biomass and carbon dioxide entering the gasifier are gasified to generate a crude synthesis gas rich in carbon monoxide, carbon dioxide and hydrogen;

[0098] 4. The crude synthesis gas is separated from acid gases such as carbon dioxide by acid gas removal and supplied to the gasifier; deacidified synthesis gas mainly composed of carbon monoxide and hydrogen is generated; the deacidified synthesis gas is passed through a gas separation unit to generate high-purity hydrogen and carbon monoxide;

[0099] 5. After carbon monoxide enters the dimethyl oxalate synthesis unit, it reacts with oxygen as a raw material to generate dimethyl oxalate; the dimethyl oxalate entering the ethylene glycol synthesis unit reacts with the hydrogen in the electrolyzer and the hydrogen generated by the gas separation unit as raw materials to generate crude ethylene glycol; the crude ethylene glycol is converted into high-purity ethylene glycol through the ethylene glycol refining unit.

[0100] The output of ethylene glycol produced in this way is 36 tons per hour.

[0101] In summary, in the embodiment of the present invention, the electrolytic hydrogen production device and the biomass ethylene glycol production device are organically coupled, and each other's products or by-products are used as their own production raw materials, thereby achieving overall efficiency improvement and emission reduction of the equipment. Specifically, the electrolytic hydrogen production device in the embodiment of the present invention uses high-temperature water vapor prepared by high-temperature waste heat of the gasifier as a raw material to prepare hydrogen and oxygen; and the ethylene glycol synthesis unit and the dimethyl oxalate synthesis unit of the gasifier use the hydrogen and oxygen generated by the electrolytic hydrogen production device as raw materials, respectively, to prepare ethylene glycol.

[0102] As can be seen from the above, in the embodiment of the present invention, on the one hand, the electrolytic hydrogen production device uses the high-temperature water vapor prepared by the high-temperature waste heat of the gasifier as a raw material to prepare hydrogen and oxygen, thereby realizing the effective utilization of the byproduct (waste heat) that is difficult to utilize in the gasifier, so as to improve the preparation efficiency of hydrogen and oxygen; on the other hand, since the present invention can supplement the hydrogen-carbon ratio required for the preparation of ethylene glycol by the hydrogen generated by the electrolytic hydrogen production device, there is no need to use the carbon monoxide generated by the separation unit to produce hydrogen to supplement the hydrogen-carbon ratio as in the prior art, thus avoiding the carbon dioxide generated in the process of hydrogen production from carbon monoxide. This not only improves the utilization value of carbon monoxide, but also solves the problem of carbon emission pollution caused by the use of carbon monoxide to produce hydrogen in the prior art. In addition, since the cost of electrolytic hydrogen production in the embodiment of the present invention is lower than the cost of using carbon monoxide to prepare hydrogen, the overall operating cost of the equipment can be effectively reduced through the embodiment of the present invention.

[0103] Furthermore, in an embodiment of the present invention, the carbon monoxide outlet of the gas separation unit can also be connected to a carbon monoxide storage unit. In this way, when the carbon monoxide generated by the gas separation unit is sufficient to generate dimethyl oxalate and there is still a surplus, the carbon monoxide with economic value can be stored in the carbon monoxide storage unit. In this way, the overall economic benefits of the equipment are improved while maintaining negative carbon emissions.

[0104] Furthermore, in the embodiment of the present invention, the carbon dioxide generated by the acid gas removal unit can also be fed back to the gasifier unit to be used for generating syngas, which can further reduce carbon emissions.

[0105] Furthermore, in an embodiment of the present invention, the oxygen output pipeline of the electrolytic hydrogen production device can also be connected to the gasifier unit. In this way, when the oxygen generated by the electrolytic hydrogen production device is sufficient to meet the needs of generating dimethyl oxalate and there is a surplus, it can be used to supplement the oxygen demand of the gasifier unit, thereby improving the efficiency of the gasifier unit in preparing synthesis gas.

[0106] Embodiment 2

[0107] Corresponding to the above system embodiment, another aspect of the present invention provides a method for producing ethylene glycol from biomass, such as Figure 3 As shown, including:

[0108] On the one hand, the electrolytic hydrogen production device receives the high-temperature steam generated by the waste heat recovery unit as electrolytic raw material to generate oxygen and hydrogen;

[0109] In the embodiment of the present invention, the waste heat recovery unit prepares water vapor through the waste slag of the gasifier, and the obtained high-temperature water vapor enters the electrolytic cell of the electrolytic hydrogen production device as an electrolysis raw material to generate oxygen and hydrogen. The embodiment of the present invention realizes the effective utilization of the by-product (waste heat) of the gasifier that is difficult to utilize, so as to improve the preparation efficiency of hydrogen and oxygen.

[0110] On the other hand, the dimethyl oxalate synthesis unit obtains the oxygen generated by the electrolytic hydrogen production device and the carbon monoxide generated by the gas separation unit to generate dimethyl oxalate;

[0111] In the embodiment of the present invention, oxygen generated by the electrolytic hydrogen production device and carbon monoxide generated by the gas separation unit are used as raw materials to enter the dimethyl oxalate synthesis unit to generate dimethyl oxalate. The carbon monoxide generated by the gas separation unit is used to meet the needs of generating dimethyl oxalate and does not need to be used to prepare hydrogen, thereby improving the utilization value of carbon monoxide.

[0112] On the other hand, the ethylene glycol synthesis unit obtains the dimethyl oxalate, the hydrogen generated by the electrolytic hydrogen production device and the hydrogen generated by the gas separation unit to produce ethylene glycol.

[0113] In the embodiment of the present invention, dimethyl oxalate generated by a dimethyl oxalate synthesis unit, hydrogen generated by an electrolytic hydrogen production device, and hydrogen generated by a gas separation unit are used as raw materials to generate crude ethylene glycol through an ethylene glycol synthesis unit; the crude ethylene glycol is then passed through an ethylene glycol refining unit to generate high-purity ethylene glycol; in the embodiment of the present invention, the hydrogen generated by the electrolytic hydrogen production device is used to supplement the hydrogen-to-carbon ratio required for preparing ethylene glycol, thereby avoiding the problem of carbon emission pollution caused by carbon dioxide generated in the process of producing hydrogen from carbon monoxide.

[0114] Furthermore, in the embodiment of the present invention, the following may also be included:

[0115] When the carbon monoxide generated by the gas separation unit meets the requirements for generating dimethyl oxalate, the remaining carbon monoxide is stored in a preset carbon monoxide storage unit. Specifically, in an embodiment of the present invention, the carbon monoxide outlet of the gas separation unit is connected to the carbon monoxide storage unit, so that when the carbon monoxide generated by the gas separation unit meets the requirements for generating dimethyl oxalate and there is a surplus, the carbon monoxide with economic value can be stored through the carbon monoxide storage unit; in this way, the overall economic benefits of the equipment are improved under the condition of negative carbon emissions.

[0116] Furthermore, in the embodiment of the present invention, the following may also be included:

[0117] After the oxygen meets the requirement for generating dimethyl oxalate, the remaining oxygen is used as the oxygen supply of the gasifier unit. Specifically, in the embodiment of the present invention, the oxygen output pipeline of the electrolytic hydrogen production device can also be connected to the gasifier unit, so that when the oxygen generated by the electrolytic hydrogen production device meets the requirement for generating dimethyl oxalate and there is a surplus, it can be used to supplement the oxygen demand of the gasifier unit, thereby improving the efficiency of the gasifier unit in preparing synthesis gas.

[0118] Furthermore, in the embodiment of the present invention, the following may also be included:

[0119] The carbon dioxide generated by the acid gas removal unit is transported to the gasifier unit. Specifically, in the embodiment of the present invention, part of the carbon dioxide generated by the acid gas removal unit can also be used as a gas raw material for the gasifier unit to reduce the overall carbon emissions of the equipment.

[0120] It should be noted that since the biomass-to-ethylene glycol method in the embodiment of the present invention is a specific use mode of the embodiment 1, the beneficial effects obtained are consistent with the beneficial effects of the biomass-to-ethylene glycol system in the embodiment, and will not be repeated here.

[0121] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A biomass to ethylene glycol system, characterized in that: include: Electrolysis hydrogen production unit and biomass to ethylene glycol unit; The biomass-to-ethylene glycol device comprises a waste heat recovery unit, a gas separation unit, a dimethyl oxalate synthesis unit and an ethylene glycol synthesis unit; wherein, The carbon monoxide outlet of the gas separation unit is connected to the dimethyl oxalate synthesis unit; the hydrogen outlet of the gas separation unit is connected to the ethylene glycol synthesis unit; The electrolytic cell of the electrolytic hydrogen production device is connected to the high-temperature water vapor outlet of the waste heat recovery unit; the oxygen outlet of the electrolytic hydrogen production device is connected to the dimethyl oxalate synthesis unit; and the hydrogen outlet of the electrolytic hydrogen production device is connected to the ethylene glycol synthesis unit.

2. The biomass to ethylene glycol system according to claim 1, characterized in that: Also includes: A carbon monoxide storage unit is connected to the carbon monoxide outlet of the gas separation unit.

3. The biomass to ethylene glycol system according to claim 1, characterized in that: The electrolytic hydrogen production device comprises: Wind and / or solar power generation units, batteries, electrolyzers, hydrogen storage tanks and oxygen storage tanks.

4. The biomass to ethylene glycol system according to claim 1, characterized in that: The biomass to ethylene glycol device comprises: pretreatment unit, gasifier unit, acid gas removal unit and glycol refining unit; The pretreatment unit transports the crushed biomass to the gasification furnace unit; The waste residue outlet of the gasifier unit is connected to the waste heat recovery unit, and the synthesis gas outlet of the gasifier unit is connected to the acid gas removal unit; The ethylene glycol refining unit is connected to the ethylene glycol synthesis unit.

5. The biomass to ethylene glycol system according to claim 4, characterized in that: The oxygen output pipeline of the electrolytic hydrogen production device also includes an output branch connected to the gasifier unit.

6. The biomass to ethylene glycol system according to claim 4, characterized in that: Also includes: A carbon dioxide recycling pipeline between the carbon dioxide outlet of the acid gas removal unit and the gasifier unit.

7. The biomass to ethylene glycol system according to claim 1, characterized in that: The dimethyl oxalate synthesis unit comprises: A carbonylation mechanism for preparing dimethyl oxalate using carbon monoxide and methyl nitrite, and, Mechanism for regenerating methyl nitrite using nitric oxide and methanol to prepare methyl nitrite.

8. The biomass to ethylene glycol system according to claim 7, characterized in that: The methyl nitrite regeneration mechanism is connected to the methanol outlet of the ethylene glycol refining unit.

9. The biomass to ethylene glycol system according to claim 1, characterized in that: The electrolytic cell is in communication with the steam generator of the waste heat recovery unit.

10. The biomass to ethylene glycol system according to claim 3, characterized in that: A hydrogen purification mechanism is also provided between the electrolyzer and the hydrogen storage tank.

11. A method for producing ethylene glycol from biomass, used in the biomass to ethylene glycol system as claimed in any one of claims 1 to 10, characterized in that: include: The electrolytic hydrogen production device receives the high-temperature steam generated by the waste heat recovery unit as an electrolytic raw material to generate oxygen and hydrogen; The dimethyl oxalate synthesis unit obtains the oxygen generated by the electrolytic hydrogen production device and the carbon monoxide generated by the gas separation unit to generate dimethyl oxalate; The ethylene glycol synthesis unit obtains the dimethyl oxalate, the hydrogen generated by the electrolytic hydrogen production device and the hydrogen generated by the gas separation unit to generate ethylene glycol.

12. The method for producing ethylene glycol from biomass according to claim 11, characterized in that: Also includes: When the carbon monoxide generated by the gas separation unit meets the requirement for generating dimethyl oxalate, the remaining carbon monoxide is stored in a preset carbon monoxide storage unit.

13. The method for producing ethylene glycol from biomass according to claim 11, characterized in that: Also includes: When the oxygen generated by the electrolytic hydrogen production device meets the requirement for generating dimethyl oxalate, the remaining oxygen is used as the oxygen supply for the gasifier unit.

14. The method for producing ethylene glycol from biomass according to claim 11, characterized in that: Also includes: The carbon dioxide generated by the acid gas removal unit is transported to the gasifier unit.

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