Method for co-producing synthesis gas by green hydrogen refining zero-carbon cement

Abstract

This invention discloses a method for producing zero-carbon cement and co-producing syngas using green hydrogen. By coupling "green hydrogen" prepared from renewable energy with the decomposition of cement raw materials, high-temperature emission reduction and efficiency enhancement are achieved to produce "zero-carbon cement," while simultaneously producing syngas in situ. Compared to the traditional high-temperature calcination process for cement production, this invention significantly reduces the cement production temperature. Furthermore, it generates high-value-added chemicals in situ during calcination, producing no carbon dioxide. This results in significant energy savings and emission reduction, greatly mitigating the greenhouse effect and realizing the production of "zero-carbon cement" and the green, low-carbon, and circular development of the cement industry.

Description

Technical Field

[0001] This invention belongs to the field of zero-carbon emission cement preparation technology, specifically relating to a method for producing zero-carbon cement and co-producing syngas using green hydrogen refining. Background Technology

[0002] The cement industry is the world's third-largest energy consumer and the second-largest CO2 emitter, accounting for approximately 7% of global CO2 emissions. Carbonates (CaCO3) are a fundamental raw material in the cement industry. During high-temperature (above 900℃) thermal decomposition, they generate metal oxides that serve as industrial raw materials, releasing large amounts of carbon dioxide, accounting for 60% of carbon emissions during cement clinker calcination. This leads to significant environmental and energy consumption problems. Therefore, carbon emission reduction in the heavily polluting cement industry is imperative and urgent. Developing methods for producing "zero-carbon cement" with zero CO2 emissions and generating high-value-added chemicals is one effective way to achieve green, low-carbon, sustainable, and circular development in the cement industry. However, the key scientific and technological challenges involved remain significant. Summary of the Invention

[0003] This invention is proposed to overcome the shortcomings of the prior art, and its purpose is to provide a method for green hydrogen coupling cement raw material refining to produce zero-carbon cement and syngas for carbon dioxide emission reduction and efficiency improvement.

[0004] This invention is achieved through the following technical solution:

[0005] A method for producing zero-carbon cement and co-producing syngas using green hydrogen includes the following steps:

[0006] (I) Using renewable energy as a power source to produce green hydrogen;

[0007] (II) The prepared green hydrogen is introduced into the cement raw meal components as a reducing gas and subjected to high-temperature pyrolysis treatment to obtain zero-carbon cement, while syngas is generated in situ.

[0008] (III) Prepare liquid high-value-added chemicals from syngas via Fischer-Tropsch synthesis reaction.

[0009] In the above technical solution, the renewable energy source includes wind power or solar power.

[0010] In the above technical solution, the method for preparing green hydrogen includes any one or more of the following: water electrolysis for hydrogen production, water photolysis for hydrogen production, or photoelectric water electrolysis for hydrogen production.

[0011] In the above technical solution, the cement raw meal includes the following components and the mass fraction of each component:

[0012] Limestone 65-75%;

[0013] Clay 15-25%;

[0014] Ferric oxide 3-5%.

[0015] In the above technical solution, the volume concentration of hydrogen in the reducing gas is 10% to 100%.

[0016] In the above technical solution, during the high-temperature pyrolysis process, the gas flow rate of the reducing gas is 20 mL / min to 500 mL / min.

[0017] In the above technical solution, the pyrolysis temperature of the high-temperature pyrolysis treatment is 400℃~1200℃, the heating rate is 5℃ / min~40℃ / min, and the high-temperature pyrolysis treatment time is 5min~200min.

[0018] In the above technical solution, the liquid high-value-added chemicals include hydrocarbons or hydrocarbon compounds.

[0019] The beneficial effects of this invention are:

[0020] This invention provides a method for producing zero-carbon cement and co-producing syngas from cement raw materials using green hydrogen coupled with carbon dioxide emission reduction and efficiency enhancement. By coupling "green hydrogen" prepared from renewable energy with the decomposition of cement raw materials, high-temperature emission reduction and efficiency enhancement are achieved in producing "zero-carbon cement," while simultaneously co-producing syngas in situ. Compared to the traditional high-temperature calcination process for cement production, this method significantly reduces the cement production temperature. Furthermore, it generates high-value-added chemicals such as carbon monoxide in situ during calcination, without producing carbon dioxide. This results in significant energy savings and emission reduction, greatly mitigating the greenhouse effect and achieving the production of "zero-carbon cement" and the green, low-carbon, and circular development of the cement industry. Simultaneously, while producing "zero-carbon cement," this invention utilizes "green hydrogen" to break Ca-O bonds in situ, generating high-value-added syngas. This syngas can be further processed through Fischer-Tropsch synthesis to produce liquid hydrocarbons or other high-value-added chemicals, further improving the economic efficiency of "zero-carbon cement" production and accelerating the cement industry's dual-carbon goals of carbon peaking and carbon neutrality. This method has broad application prospects. Attached Figure Description

[0021] Figure 1 These are scanning electron microscope images of cement raw materials in Embodiment 1 of the present invention;

[0022] Figure 2 These are scanning electron microscope images of the zero-carbon cement prepared in Example 1 of this invention;

[0023] Figure 3 These are X-ray diffraction patterns of cement raw materials and zero-carbon cement in Embodiment 1 of the present invention;

[0024] Figure 4This is the gas chromatogram of the product in Example 1 of the present invention;

[0025] Figure 5 This is a BET comparison chart of the cement products prepared in Example 1 and Comparative Example 1 of the present invention;

[0026] Figure 6 This is a comparison chart of CO-TPSR-MS of cement raw materials and unadded ferric oxide in Example 1 and Comparative Example 2 of the present invention.

[0027] For those skilled in the art, other related figures can be obtained from the above figures without any creative effort. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0029] In this invention, "green hydrogen" refers to hydrogen produced using renewable energy as a power source, i.e., green hydrogen, and the preparation method adopts water electrolysis hydrogen production technology or photoelectric water electrolysis hydrogen production technology; "zero-carbon cement" refers to cement that has no carbon dioxide emissions during the preparation process, and "zero-carbon cement" includes, but is not limited to, silicate cement.

[0030] Example 1

[0031] The cement raw materials used in this embodiment are limestone, clay, and ferric oxide. The specific steps for coupling the cement raw materials with "green hydrogen" at high temperature to reduce emissions and increase efficiency in the production of "zero-carbon cement" and co-producing syngas are as follows:

[0032] (I) Using renewable energy to power the production of "green hydrogen"

[0033] Using nickel-iron hydrotalcite as the anode, a commercial Pt / C catalyst as the cathode, and a 30 wt% potassium hydroxide solution as the electrolyte, an electrolysis was performed at a current density of 200 mA / cm². -2 Under these conditions, hydrogen is produced by water electrolysis. The produced gas is directly connected to a tube furnace after passing through a recovery system and a filtration system. The hydrogen gas flow rate is set to 200 mL / min.

[0034] (II) The prepared "green hydrogen" is introduced into the cement raw materials and subjected to high-temperature pyrolysis treatment to obtain "zero carbon cement" and at the same time, syngas is generated in situ.

[0035] Take 50g of cement raw materials (37.5g limestone, 10g clay, 2.5g ferric oxide) and spread them evenly in a tube furnace. Set the pyrolysis temperature to 600℃, the heating rate to 10℃ / min, and the reaction time to 200min. After calcination, "zero-carbon cement" is obtained, and the ratio of H2 to CO in the synthesis gas is 3:1.

[0036] Depend on Figure 1 , 2 As can be seen, after calcination at 600℃, the sample surface became porous and rough, which is due to CO release; from Figure 3 The X-ray diffraction patterns of cement raw materials and "zero-carbon cement" show that after calcination, the calcium carbonate in the calcite phase is completely transformed into calcium oxide.

[0037] Figure 4 This is a gas chromatogram of the product in Example 1 of the present invention. As can be seen from the figure, the ratio of H2 to CO in the product is close to 3:1.

[0038] Comparative Example 1

[0039] The cement raw materials used in this comparative example only contain calcium carbonate and ferric oxide. The specific steps for coupling them with "green hydrogen" for high-temperature emission reduction and efficiency enhancement in the refining of calcium oxide / ferric oxide to co-produce syngas are as follows:

[0040] (I) Using renewable energy to power the production of "green hydrogen"

[0041] Using nickel-iron hydrotalcite as the anode, a commercial Pt / C catalyst as the cathode, and a 30 wt% potassium hydroxide solution as the electrolyte, an electrolysis was performed at a current density of 200 mA / cm². -2 Under these conditions, hydrogen is produced by water electrolysis. The produced gas is directly connected to a tube furnace after passing through a recovery system and a filtration system. The hydrogen gas flow rate is set to 100 mL / min.

[0042] (II) The prepared "green hydrogen" is introduced into some components of cement raw materials and subjected to high-temperature pyrolysis treatment to obtain calcium oxide / ferric oxide, while syngas is generated in situ.

[0043] 10g of limestone / ferric oxide mixture (9.375g calcium carbonate, 0.625g ferric oxide) was spread evenly in a tube furnace. The pyrolysis temperature was set to 600℃, the heating rate was 5℃ / min, and the reaction time was 60min. After calcination, calcium oxide / ferric oxide products were obtained. When the temperature was raised to 600℃, the gas was collected by a gas bag and analyzed by a gas chromatograph. The ratio of H2 to CO in the synthesis gas was 1:1.

[0044] Compared to Example 1, this comparative example's cement raw meal did not contain clay. The role of clay in cement raw meal is to provide Si and Al chemical elements for cement production, improving the dispersibility during mixing and the strength and water resistance after calcination. Figure 5 As can be seen, the addition of clay increases the dispersion of cement clinker produced by the pyrolysis of cement raw materials, causing the specific surface area to increase from 4.7848 m². 2 / g increased to 32.8768m 2 / g, while reducing the pore size.

[0045] Comparative Example 2

[0046] The cement raw materials used in this comparative example only contain calcium carbonate and clay. The specific steps for coupling them with "green hydrogen" high-temperature emission reduction and efficiency enhancement to produce calcium silicate and co-generate syngas are as follows:

[0047] (I) Using renewable energy to power the production of "green hydrogen"

[0048] Using nickel-iron hydrotalcite as the anode, a commercial Pt / C catalyst as the cathode, and a 30 wt% potassium hydroxide solution as the electrolyte, an electrolysis was performed at a current density of 200 mA / cm². -2 Under these conditions, hydrogen is produced by water electrolysis. The produced gas is directly connected to a tube furnace after passing through a recovery system and a filtration system. The hydrogen gas flow rate is set to 100 mL / min.

[0049] (II) The prepared "green hydrogen" is introduced into the cement raw meal components and subjected to high-temperature pyrolysis treatment to obtain "zero carbon cement" and at the same time, syngas is generated in situ.

[0050] 20g of limestone / clay (15.8g limestone, 4.2g clay) was spread evenly in a tube furnace. The pyrolysis temperature was set to 700℃, the heating rate was 10℃ / min, and the reaction time was 100min. After calcination, calcium silicate product was obtained. The ratio of H2 to CO in the synthesis gas was 1:1.

[0051] Compared to the examples, the cement raw meal in this comparative example did not contain ferric oxide. The role of ferric oxide in cement raw meal is to provide Fe chemical elements for cement production, lower the calcination temperature during cement production, accelerate the reaction, and also increase the wear resistance of the hardened cement. Figure 6 As can be seen, compared with calcium carbonate-clay components, the addition of ferric oxide to cement raw materials can reduce the decomposition temperature of calcium carbonate and generate high-value-added CO gas products in situ. Under the condition of 600℃, the intensity of CO generation in situ from the thermal decomposition of cement raw materials with added ferric oxide is close to the peak value, while the calcium carbonate-clay components without added ferric oxide have just begun to generate CO through thermal decomposition.

[0052] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0053] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for producing zero-carbon cement and co-producing syngas using green hydrogen refining, characterized in that: Includes the following steps: (I) Utilizing renewable energy as a power source to produce green hydrogen; (II) The prepared green hydrogen is introduced into the cement raw material components as a reducing gas and subjected to high-temperature pyrolysis treatment to obtain zero-carbon cement, while syngas is generated in situ. The cement raw meal includes the following components and their mass fractions: Limestone 75%; 20% clay; 5% ferric oxide; The high-temperature pyrolysis treatment has a pyrolysis temperature of 600°C, a heating rate of 10°C / min, and a high-temperature pyrolysis treatment time of 200min. The syngas contains H2 in a 3:1 ratio of CO; the syngas is used to prepare liquid high-value-added chemicals via Fischer-Tropsch synthesis.

2. The method for producing zero-carbon cement and co-producing syngas using green hydrogen refining according to claim 1, characterized in that: The renewable energy sources include wind or solar power.

3. The method for producing zero-carbon cement and co-producing syngas using green hydrogen refining according to claim 1, characterized in that: The method for preparing green hydrogen includes any one or more of the following: hydrogen production by electrolysis of water, hydrogen production by photolysis of water, or hydrogen production by photoelectric electrolysis of water.

4. The method for producing zero-carbon cement and co-producing syngas using green hydrogen refining according to claim 1, characterized in that: The volume concentration of hydrogen in the reducing gas is 10% to 100%.

5. The method for producing zero-carbon cement and co-producing syngas using green hydrogen refining according to claim 1, characterized in that: During the high-temperature pyrolysis process, the gas flow rate of the reducing gas is 20 mL / min to 500 mL / min.

6. The method for producing zero-carbon cement and co-producing syngas using green hydrogen refining according to claim 1, characterized in that: The liquid high-value-added chemicals include hydrocarbons or hydrocarbon compounds.

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