Method for preparing hydrogen-rich synthesis gas by treating kitchen waste biogas residues and waste plastics through steam co-gasification

Abstract

The invention discloses a method for preparing hydrogen-rich synthesis gas by treating kitchen waste biogas residues and waste plastics through steam co-gasification, belongs to the technical field of biomass waste resource utilization, and particularly relates to a method for preparing hydrogen-rich synthesis gas by treating kitchen waste biogas residues and waste plastics through steam co-gasification. Comprising the following steps: drying and grinding kitchen waste biogas residues and waste plastics, and gasifying by taking water vapor as a gasifying agent to prepare hydrogen-rich synthesis gas; wherein the mass ratio of the kitchen waste biogas residues to the waste plastics is (1: 3)-(3: 1). According to the method, kitchen waste biogas residues and waste plastics are used as raw materials, steam co-gasification is carried out, efficient conversion from kitchen waste and waste plastics to high-quality hydrogen-rich synthesis gas is achieved, the limitation of gasification of a single substance is solved, a clean and efficient potential resource recovery mode is provided for kitchen waste anaerobic fermentation by-products, and the method is suitable for industrial production. Meanwhile, the development of clean energy is promoted.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomass waste resource utilization, and in particular relates to a method for preparing hydrogen-rich synthesis gas by treating kitchen waste sludge and waste plastics through water vapor co-gasification. Background Art

[0002] With economic growth and improved living standards, the production of food waste has increased annually. 74% of food waste is treated through anaerobic digestion. However, anaerobic digestion is selective in its degradation, and waste plastics mixed in during the food waste recycling process are not biodegradable. Left in the natural environment, they pose a threat to ecological safety and human health. Furthermore, anaerobic digestion has limited biodegradability, resulting in a large amount of residual biogas residue. Currently, the main methods of biogas residue disposal are landfill or composting, but land carrying capacity is limited, and landfilling and composting can lead to environmental problems such as groundwater contamination. Therefore, the scientific disposal of food waste and waste plastics is an urgent issue that needs to be addressed.

[0003] Gasification technology can effectively convert food waste biogas and waste plastics into hydrogen-rich syngas, thereby realizing resource utilization. However, the anaerobic fermentation process consumes organic matter from food waste, resulting in a high ash content in the biogas. The carbon residue produced by gasification can easily clog the discharge port and corrode the pipe walls. Plastics, on the other hand, transform into a molten state under high temperatures, forming wax that adheres to the pipe walls, leading to uneven heat transfer and localized overheating.

[0004] Therefore, in order to solve the problems of large output of food waste sludge, difficult treatment and difficult degradation of waste plastics in the above-mentioned process, it is urgently necessary to provide a new method for preparing hydrogen-rich synthesis gas, which can be used to fully utilize food waste sludge and waste plastics and efficiently convert them into high-quality hydrogen-rich synthesis gas. Summary of the Invention

[0005] To address the above technical issues, the present invention proposes a method for producing hydrogen-rich syngas from food waste digestate and waste plastics through steam co-gasification. By using food waste digestate and waste plastics as raw materials for steam co-gasification, the method achieves efficient conversion of food waste and waste plastics into high-quality, hydrogen-rich syngas. This overcomes the limitations of single-substance gasification, provides a clean and efficient potential resource recovery method for anaerobic fermentation byproducts of food waste, and promotes the development of clean energy.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing hydrogen-rich syngas by treating food waste biogas residue and waste plastics through water vapor co-gasification comprises the following steps:

[0008] The kitchen waste sludge and waste plastics are dried and ground, and then gasified using steam as a gasifying agent to produce hydrogen-rich synthesis gas;

[0009] The mass ratio of the kitchen waste sludge to the waste plastic is 1:3-3:1.

[0010] Beneficial Effects: The present invention utilizes water vapor as a gasifying agent to optimize composition during the gasification process. By enhancing methane reforming and the water-gas reaction, this increases H2 and CO concentrations and improves syngas quality. More importantly, by adjusting the mixing ratio of food waste biogas residue and waste plastics, as well as the amount of water vapor added, the CO / H2 ratio of the gasification product can be further controlled, providing a suitable precursor for subsequent processing into clean fuels and other high-value-added chemicals.

[0011] Optionally, the mass ratio of the kitchen waste sludge to waste plastic is 3:1, 1:1 or 1:3.

[0012] Optionally, the drying process is carried out at 105° C. for 24 hours.

[0013] Beneficial effects: The present invention can effectively reduce the moisture content of the raw materials by drying the raw materials, avoid the water consuming a large amount of heat during the gasification process, improve energy utilization, and help improve the efficiency of subsequent gasification reactions.

[0014] Optionally, the grinding is performed to a particle size of 30-50 meshes.

[0015] Beneficial effects: The present invention limits the grinding of the two raw materials to a particle size of 30-50 mesh; it has the following advantages:

[0016] Increased reaction contact area: Smaller particle size increases the contact area with water vapor and accelerates the reaction rate;

[0017] Improve gasification efficiency: fine particles help to evenly distribute heat, reducing local overheating or unreacted areas;

[0018] Improve gas-solid flow characteristics: moderate particle size can avoid clogging the gasifier feed port and ensure continuous operation stability;

[0019] Facilitates uniform mixing: provides a physical basis for the full mixing of food waste sludge and waste plastics, and improves the synergistic gasification effect.

[0020] Optionally, the water vapor introduction rate is 0.3-1.2 mL / min.

[0021] Furthermore, the water vapor introduction rate is 0.3, 0.6, 0.9 or 1.2 mL / min.

[0022] Optionally, the gasification process is:

[0023] The kitchen waste biogas residue and waste plastic are mixed evenly, placed on the upper part of the gasification furnace, and then nitrogen is introduced to exhaust the air in the furnace;

[0024] Turn on the gasification furnace and heat it to 800℃, then keep the temperature constant for 20 minutes;

[0025] Finally, push the two raw materials to the center of the gasifier, turn on the steam generator, and start steam gasification.

[0026] Furthermore, the N2 introduction rate is 100 mL / min.

[0027] Furthermore, the heating rate of the heating process is 10°C / min.

[0028] Compared with the prior art, the present invention has the following advantages and technical effects:

[0029] (1) The present invention adopts co-gasification to treat food waste sludge and waste plastics. Food waste sludge and waste plastics have certain complementarity in chemical composition, and produce a synergistic effect when co-gasified, thereby improving the utilization rate of food waste sludge and waste plastics and solving the limitation problem of separate gasification of food waste sludge and waste plastics.

[0030] (2) As a byproduct of anaerobic fermentation of food waste, food waste sludge is generally considered waste and may pollute the environment if not handled properly. Traditionally, waste plastics are often incinerated or discarded, which also results in resource waste and environmental pollution. The present invention uses food waste sludge and waste plastics as raw materials, combining them for co-gasification, thereby achieving resource utilization of waste and reducing the risk of environmental pollution.

[0031] (3) The present invention introduces water vapor as a gasifying agent during the co-gasification process, significantly improving the gas yield. This significantly increases the gas yield compared to when no water vapor is added, which directly improves the energy efficiency and economy of the gasification process. The yields of H2, CO2, and CO increase with increasing water vapor addition, while the yield of CH4 decreases. This change in gas composition is more conducive to the synthesis of hydrogen-rich gas, which is of great significance for subsequent hydrogen energy utilization or chemical synthesis.

[0032] (4) The entire preparation process of the present invention does not introduce other chemical reagents, which has the advantage of being environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0034] Figure 1The product distribution diagram (a) and gas phase product distribution diagram (b) of the water vapor co-gasification of food waste biogas residue and waste plastics at different water vapor addition amounts in Example 1;

[0035] Figure 2 The product distribution diagram (a) and gas phase product distribution diagram (b) of the water vapor co-gasification of food waste biogas residue and waste plastics at different mixing ratios in Example 2;

[0036] Figure 3 This is a flow chart of the present invention's water vapor co-gasification treatment of kitchen waste sludge and waste plastics to produce hydrogen-rich synthesis gas. DETAILED DESCRIPTION

[0037] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0038] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0039] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0040] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0041] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0042] The present invention uses a mixture of kitchen waste sludge and waste plastics as a co-gasification raw material; then introduces water vapor as a gasifying agent to improve the gas yield and gas quality. The final product prepared is hydrogen-rich synthesis gas, which is environmentally friendly and has economic benefits.

[0043] The embodiment of the present invention discloses a method for preparing hydrogen-rich syngas by treating food waste and waste plastics through water vapor co-gasification, comprising the following steps:

[0044] (1) Raw material pretreatment stage: restaurant kitchen waste sludge (i.e., anaerobic fermentation sludge of restaurant kitchen waste) and waste plastics are selected as gasification raw materials; the restaurant kitchen waste sludge and waste plastics are dried at 105°C for 24 hours and then mechanically crushed, and the particle size of the crushed raw materials is adjusted to 30-50 mesh using screening equipment;

[0045] (2) Gasification stage: After the food waste sludge and waste plastics are mixed in a certain proportion, they are placed on the top of the gasifier. N2 is introduced at a rate of 100 mL / min to exhaust the air in the furnace;

[0046] Start the gasification furnace heating program, and when the temperature reaches 800℃, keep the constant temperature for 20 minutes;

[0047] Push the raw materials to the center of the gasifier, turn on the steam generator, and perform steam gasification;

[0048] The synthesis gas produced by gasification is collected through a condensation system.

[0049] (3) Gas collection stage: Within 20 minutes of the gasification reaction, the generated synthesis gas is collected using a gas bag. The synthesis gas composition is: H2, CH4, CO and CO2.

[0050] In some optional embodiments, in step (2), the synthesis gas produced by gasification is condensed through a spiral condenser at -10°C and then collected.

[0051] In some optional embodiments, in step (3), a gas bag is used to collect the gaseous product, and the synthesis gas is measured by a gas chromatograph (GC2030, Shimadzu).

[0052] Unless otherwise specified, the "room temperature" in the present invention refers to 20-30°C.

[0053] The raw materials used in the present invention are all purchased from the market.

[0054] The technical solution of the present invention is further illustrated by the following examples.

[0055] Example 1

[0056] like Figure 3As shown, a method for preparing hydrogen-rich syngas by treating food waste and waste plastics by water vapor co-gasification comprises the following steps:

[0057] The kitchen waste sludge and waste plastic were dried at 105°C for 24 hours and then mechanically crushed, and the particle size of the crushed raw materials was adjusted to 30-50 mesh using screening equipment; then a mixture of kitchen waste sludge and waste plastic with a mixing ratio (mass ratio) of 1:1 was added to the reaction funnel of the gasifier, and the reaction funnel was fixed on the gasifier; the cold well was opened and the circulating water temperature was set to -10°C; the gasifier heating program was turned on, and the temperature was heated from room temperature to 800°C at a heating rate of 10°C / min and maintained for 20 minutes; when the temperature reached 800°C, the reaction funnel was pushed to the center of the gasifier, and the steam generator was turned on, and the water vapor addition amount was set to 0, 0.3, 0.6, 0.9 and 1.2 mL / min, respectively (that is, except for the different water vapor addition amounts, the other gasification conditions were the same), and the prepared synthesis gases were named S0, S0.3, S0.6, S0.9 and S1.2, respectively; the generated gas was collected using an air bag.

[0058] Synthesis gas was measured using a gas chromatograph (GC2030, Shimadzu). High-purity argon was used as the carrier gas at a flow rate of 8.0 mL / min, and the injector, column, and detector temperatures were set at 150°C, 120°C, and 200°C, respectively. Calibration standards included 15.00% CH₄, 15.00% CO₂, 10.00% CO, 10.00% H₂, 10.00% C₂H₆, 10.00% C₂H₄, and 30.00% N₂.

[0059] Figure 1 The product distribution diagram (a) and gas phase product distribution diagram (b) of the water vapor co-gasification of kitchen waste sludge and waste plastics under different water vapor addition amounts in Example 1. As can be seen from the figure, when the water vapor addition amount is 0, the gas yield is 37.77wt.%, and the gas yield is also continuously increasing as the water vapor addition amount increases. When the water vapor addition amount reaches 1.2mL / min, the gas yield is 60.14wt.%. From the perspective of gas components, as the water vapor addition amount increases, the yields of H2, CO2, and CO continue to increase, and the yield of CH4 continues to decrease. This is more conducive to the conversion to hydrogen-rich synthesis gas. Compared with not passing water vapor, when the water vapor addition amount is 0.3mL / min, the proportion of H2 in synthesis gas increases from 24.82% to 44.04%. When the water vapor addition amount is continuously increased to 1.2mL / min, the proportion of H2 also increases, reaching a maximum of 51.54%.

[0060] Example 2

[0061] Food waste digestate and waste plastics were dried at 105°C for 24 hours and then mechanically crushed. Screening equipment was used to adjust the crushed material particle size to 30-50 mesh. Mixtures of food waste digestate and waste plastics were then added to the reaction funnel of a gasifier at mass ratios of 1:0, 3:1, 1:1, 1:3, and 0:1. The reaction funnels were fixed to the gasifier and designated H0, H0.25, H0.5, H0.75, and H1, respectively. The circulating water temperature was set to -10°C using a cold well. The gasifier was heated from room temperature to 800°C at a rate of 10°C / min and held for 20 minutes. When the temperature reached 800°C, the reaction funnel was moved to the center of the gasifier. The steam generator was activated at a rate of 0.9 mL / min, and the generated gas was collected using a gas bag. (Aside from the different mixing ratios, all other gasification conditions remained the same.)

[0062] Synthesis gas was measured using a gas chromatograph (GC2030, Shimadzu). High-purity argon was used as the carrier gas at a flow rate of 8.0 mL / min, and the injector, column, and detector temperatures were set at 150°C, 120°C, and 200°C, respectively. Calibration standards included 15.00% CH₄, 15.00% CO₂, 10.00% CO, 10.00% H₂, 10.00% C₂H₆, 10.00% C₂H₄, and 30.00% N₂.

[0063] Figure 2 The product distribution diagram (a) and gas phase product distribution diagram (b) of the water vapor co-gasification of food waste sludge and waste plastics at different mixing ratios in Example 2 of the present invention. It can be seen from the figure that with the increase of the mixing ratio, the yields of H2, CO2, and CO continue to decrease, while the yield of CH4 continues to increase. When the waste plastic is gasified alone (H1), the proportion of H2 in the synthesis gas is 42.65%. After the introduction of food waste sludge, the proportion of H2 continues to increase. When the mixing ratio reaches 3:1 (H0.25), the proportion of H2 reaches 50.48%, which is only 0.6% different from the gasification of food waste sludge alone (H0). That is, when the mixing ratio of food waste sludge and waste plastics is 3:1, it is possible to ensure the yield of hydrogen, achieve efficient conversion of high-quality hydrogen-rich synthesis gas, and achieve full utilization of food waste sludge and waste plastics.

[0064] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for producing hydrogen-rich syngas by treating food waste biogas residue and waste plastics through water vapor co-gasification, characterized in that: The following steps are involved: The kitchen waste sludge and waste plastics are dried and ground, and then gasified using steam as a gasifying agent to produce hydrogen-rich synthesis gas; The mass ratio of the kitchen waste sludge to the waste plastic is 1:3-3:

1.

2. The method for preparing hydrogen-rich syngas by treating food waste biogas residue and waste plastics through water vapor co-gasification according to claim 1, characterized in that: The mass ratio of the kitchen waste sludge to the waste plastic is 3:

1.

3. The method for preparing hydrogen-rich syngas by treating food waste biogas residue and waste plastics through water vapor co-gasification according to claim 1, characterized in that: The conditions in the drying process are: drying at 105° C. for 24 hours.

4. The method for preparing hydrogen-rich syngas by treating food waste biogas residue and waste plastics through water vapor co-gasification according to claim 1, characterized in that: The grinding step is to grind the particles to a size of 30-50 meshes.

5. The method for preparing hydrogen-rich syngas by treating food waste biogas residue and waste plastics through water vapor co-gasification according to claim 1, characterized in that: The water vapor introduction rate is 0.3-1.2 mL / min.

6. The method for preparing hydrogen-rich syngas by treating food waste biogas residue and waste plastics through water vapor co-gasification according to claim 5, characterized in that: The water vapor introduction rate was 1.2 mL / min.

7. The method for preparing hydrogen-rich syngas by treating food waste biogas residue and waste plastics through water vapor co-gasification according to claim 1, characterized in that: The gasification process is: The ground food waste biogas residue and waste plastics are mixed evenly and placed on the upper part of the gasifier, and then nitrogen is introduced to exhaust the air in the furnace; Then, the gasifier was turned on and heated to 800°C and kept at this temperature for 20 minutes; Then, the kitchen waste sludge and waste plastics are pushed to the center of the gasification furnace, and the steam generator is turned on to perform steam gasification.

8. The method for preparing hydrogen-rich syngas by treating food waste biogas residue and waste plastics through water vapor co-gasification according to claim 7, characterized in that: The N2 introduction rate was 100 mL / min.

9. The method for preparing hydrogen-rich syngas by treating food waste biogas residue and waste plastics through water vapor co-gasification according to claim 7, characterized in that: The heating rate of the heating process is 10°C / min.

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