A deodorizing catalyst, a method for preparing the same, and an application thereof

Abstract

The application provides a deodorization catalyst and a preparation method and application thereof, and belongs to the technical field of deodorization catalysts. The application uses pseudo-boehmite as a catalyst active carrier, and uses diiron trioxide, titanium oxide and silicon oxide as effective active components of the catalyst. Through synergistic action, the catalyst accelerates the full combustion of foul-smelling gas in the production of animal carcass treatment and feather protein powder in a incinerator under the condition of ≤700 DEG C, and converts the foul-smelling gas into harmless products such as carbon dioxide, nitrogen, sulfur, water vapor, etc., and a small amount of over-oxidized products such as sulfur dioxide and nitrogen oxides, etc. have good alkaline conditions and water solubility, and are removed by spraying an alkaline aqueous solution, so as to reach the environmental protection standard discharge, and finally realize the efficient and low-cost elimination of the foul-smelling gas generated in the production of animal carcass treatment and feather protein powder.

Description

Technical Field

[0001] This invention relates to the field of deodorization catalyst technology, and in particular to a deodorization catalyst, its preparation method, and its application. Background Technology

[0002] With the expansion of the livestock industry, the number of dead animals has increased rapidly, reaching approximately 2 million tons annually in China. If these carcasses are not handled scientifically, promptly, and properly, they can cause the spread of diseases. If the dead animals carry zoonotic diseases, the consequences are unimaginable. Untreated carcasses rot and decompose, producing foul odors that pollute the air and contaminate water sources they come into contact with. Current technology uses a "high-temperature, high-pressure rendering" method to harmlessly treat dead animals, which involves crushing the carcasses and maintaining them at temperatures above 130°C to kill bacteria and viruses, with the residue being usable as a resource. However, when treating carcasses, including internal organs, especially rotting animals, the decomposition of organic matter during high-pressure cooking produces gases with a strong odor. Furthermore, feather protein powder, a byproduct of chicken and duck slaughter, is produced industrially using a similar "high-temperature, high-pressure rendering" method to hydrolyze feathers and produce feather protein powder, which can be used in the feed industry. However, this process produces even stronger odors than the rendering method used for animal carcasses, and improper handling can cause serious air pollution.

[0003] The main components commonly found in odors include the following typical compounds: (1) Hydrogen sulfide (H2S) has an extremely strong malodor and is often associated with the putrefaction process. It is usually produced by the decomposition of sulfur-containing organic matter. The human olfactory threshold for hydrogen sulfide is 0.00041 mg / m³. 3 (1) Hydrogen sulfide has an anesthetic effect on the human olfactory nerve system. When the concentration increases to a certain level, the degree of odor perceived by people will decrease. (2) Methyl sulfide and thiols are both organic compounds containing sulfur and carbon. Their odor is often stronger than that of inorganic hydrogen sulfide. (3) Ammonia (NH3): During the putrefaction process, proteins decompose to produce ammonia gas. (4) Organic amines: such as pentanediamine (cadaverine), butylamine, indole, etc., have a strong fishy smell. (5) Aldehydes and ketones: These compounds may also be produced by the decomposition of fats during the putrefaction process and have different degrees of odor.

[0004] The odors produced during the rendering of diseased and dead animals and the cooking of feather and feather powder are a complex result of various malodorous components. Due to the complexity of the composition, the use of one or a combination of measures such as acid-base spraying, bacterial biochemical methods, strong oxidants, plasma, high-voltage electrostatics, and photocatalysis is insufficient to achieve satisfactory results. A low-cost, high-efficiency treatment method is needed for the high-temperature rendering of animal carcasses and the production of feather and feather powder. Incineration is an effective method for treating various malodorous and organic gases; for example, RTO (Regenerative Thermal Oxidizer) furnaces are commonly used in industry to treat volatile organic compounds. However, this method is too costly and its effectiveness in treating complex odorous gases is not ideal. Therefore, providing a way to efficiently and cost-effectively eliminate the malodorous gases generated during animal carcass processing and feather and feather powder production is a problem that urgently needs to be solved by existing technologies. Summary of the Invention

[0005] The purpose of this invention is to provide a deodorizing catalyst, its preparation method, and its application. The deodorizing catalyst provided by this invention can efficiently and cost-effectively eliminate malodorous gases generated during animal carcass processing and feather protein powder production.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a deodorizing catalyst, which comprises the following components in parts by mass:

[0008] 80-90 parts of pseudoboehmite, 3-8 parts of ferric oxide, 1-3 parts of titanium dioxide, 1-3 parts of silicon dioxide, and 4-8 parts of organic pore-forming agent.

[0009] Preferably, the deodorizing catalyst comprises the following components in parts by weight:

[0010] The composition consists of 82-88 parts of boehmite, 4-7 parts of ferric oxide, 1.5-2.5 parts of titanium dioxide, 1.5-2.5 parts of silicon dioxide, and 5-7 parts of organic pore-forming agent.

[0011] Preferably, the organic porogen is at least one selected from starch, polyvinyl alcohol, polyacrylamide, polyethylene oxide, deacetylated chitosan, sodium polyacrylate, hydrophilic cellulose derivatives, and hydrophilic starch derivatives.

[0012] The present invention also provides a method for preparing the deodorizing catalyst described in the above technical solution, comprising the following steps:

[0013] (1) After mixing boehmite, ferric oxide, titanium dioxide and silicon dioxide, they were crushed and sieved in sequence to obtain inorganic powder;

[0014] (2) The organic pore-forming agent is mixed with water and swollen, and then mixed with the inorganic powder obtained in step (1) to obtain mud material;

[0015] The mud material is sequentially shaped, dried, and calcined to obtain a deodorizing catalyst.

[0016] Preferably, the sieving in step (1) is through a 200-500 mesh sieve.

[0017] Preferably, in step (2), the mass ratio of the organic porogen to water is 1:(8-14).

[0018] Preferably, in step (2), the forming process involves extrusion or vibration to form columnar particles with a diameter of 2 to 10 mm.

[0019] Preferably, the drying temperature in step (2) is 50-120°C, and the drying time is 0.5-12 hours.

[0020] Preferably, the calcination temperature in step (2) is 500-800℃, and the calcination time is 4-12h.

[0021] The present invention also provides the application of the deodorizing catalyst described in the above technical solution in eliminating malodorous gases in animal carcass treatment and feather protein powder production.

[0022] This invention provides a deodorizing catalyst that uses boehmite as the active catalyst carrier and ferric oxide, titanium dioxide, and silicon dioxide as the effective active components of the catalyst. Through synergistic action, these components accelerate the complete combustion of malodorous gases generated during animal carcass processing and feather protein powder production in an incinerator at ≤700℃, converting them into harmless products such as carbon dioxide, nitrogen, sulfur, and water vapor. The small amount of over-oxidized products, such as sulfur dioxide and nitrogen oxides, have good water solubility under alkaline conditions and can be removed by spraying alkaline aqueous solution, thereby obtaining gas that meets environmental emission standards. Ultimately, this invention achieves efficient and low-cost elimination of malodorous gases generated during animal carcass processing and feather protein powder production. Attached Figure Description

[0023] Figure 1 The dimensionless bar graphs of odor identification after the deodorizing catalysts prepared in Examples 1-4 and the catalysts prepared in the comparative example catalyze the decomposition of malodorous gases generated during the preparation of feather protein powder are shown.

[0024] Figure 2 The graphs show the hydrogen sulfide concentrations after the deodorizing catalysts prepared in Examples 1-4 and the catalysts prepared in the comparative examples catalyze the decomposition of malodorous gases generated during the preparation of feather protein powder. Detailed Implementation

[0025] This invention provides a deodorizing catalyst, which comprises the following components in parts by mass:

[0026] 80-90 parts of pseudoboehmite, 3-8 parts of ferric oxide, 1-3 parts of titanium dioxide, 1-3 parts of silicon dioxide, and 4-8 parts of organic pore-forming agent.

[0027] Unless otherwise specified, all raw materials used in this invention are commercially available products in the art.

[0028] In this invention, the deodorizing catalyst preferably comprises the following components in parts by weight:

[0029] The composition consists of 82-88 parts of boehmite, 4-7 parts of ferric oxide, 1.5-2.5 parts of titanium dioxide, 1.5-2.5 parts of silicon dioxide, and 5-7 parts of organic pore-forming agent.

[0030] In this invention, the organic porogen is preferably at least one of starch, polyvinyl alcohol, polyacrylamide, polyethylene oxide, deacetylated chitosan, sodium polyacrylate, hydrophilic cellulose derivatives, and hydrophilic starch derivatives.

[0031] The present invention also provides a method for preparing the deodorizing catalyst described in the above technical solution, comprising the following steps:

[0032] (1) After mixing boehmite, ferric oxide, titanium dioxide and silicon dioxide, they were crushed and sieved in sequence to obtain inorganic powder;

[0033] (2) The organic pore-forming agent is mixed with water and swollen, and then mixed with the inorganic powder obtained in step (1) to obtain mud material;

[0034] The mud material is sequentially shaped, dried, and calcined to obtain a deodorizing catalyst.

[0035] This invention involves mixing boehmite, ferric oxide, titanium dioxide, and silicon dioxide, followed by sequential pulverization and sieving to obtain inorganic powder.

[0036] In this invention, the preferred method of pulverization is ball milling. The preferred method of sieving is passing the material through a 200-500 mesh sieve, more preferably through a 250-450 mesh sieve, and further preferably through a 325 mesh sieve. By using ball milling and sieving, this invention ensures that the raw materials undergo sufficient ball milling pretreatment to promote thorough subsequent calcination, while also guaranteeing that the prepared deodorizing catalyst possesses suitable porosity, a large specific surface area, and good strength.

[0037] After obtaining the inorganic powder, the present invention mixes the organic pore-forming agent and water to swell the mixture, and then mixes it with the inorganic powder to obtain the mud.

[0038] In this invention, the mass ratio of the organic porogen to water is preferably 1:(8-14), more preferably 1:10. This invention utilizes the organic porogen as an active carrier and simultaneously acts as a forming binder. In this invention, the swelling time is preferably 2-5 hours. This invention uses swelling to form a polymer sol, where hydrophilic groups extend from the aggregated polymer to create a temporary adhesive effect with the inorganic powder, facilitating the forming of the preform.

[0039] In this invention, the preferred method for mixing the swollen organic porogen and inorganic powder is kneading.

[0040] After obtaining the mud material, the present invention sequentially shapes, dries, and calcines the mud material to obtain a deodorizing catalyst.

[0041] In this invention, the molding process is preferably carried out by extrusion or vibration to form columnar particles with a diameter of 2 to 10 mm.

[0042] In this invention, the drying temperature is preferably 50–120°C; the drying time is preferably 0.5–12 hours; and the drying method is preferably air drying. This invention removes a large amount of moisture from the green body through drying, allowing the green body to form a stable shape and preventing cracking during subsequent firing.

[0043] In this invention, the calcination temperature is preferably 500–800°C, and the calcination time is preferably 5–12 hours. Through calcination, this invention solidifies the inorganic powder, removes organic pore-forming agents, forms pores at the positions of organic molecules, increases the specific surface area of ​​the catalyst, and thus improves the catalytic performance of the deodorizing catalyst.

[0044] The present invention also provides the application of the deodorizing catalyst described in the above technical solution in eliminating malodorous gases generated in animal carcass processing and feather protein powder production.

[0045] In this invention, the application of the deodorizing catalyst in eliminating malodorous gases during animal carcass processing and feather protein powder production includes the following steps:

[0046] The above-mentioned deodorizing catalyst is used as a packing material inside the furnace reaction bed. At a temperature below 700°C, air is blown into the furnace so that the odorous gases to be treated generated in the animal carcass processing and / or feather protein powder production are burned on the surface of the deodorizing catalyst. During the reaction, a small amount of over-oxidized products such as sulfur dioxide and nitrogen oxides are removed by spraying an alkaline aqueous solution, thereby obtaining gases that meet environmental emission standards.

[0047] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0048] Example 1

[0049] An odor-removing catalyst, comprising the following components by mass parts:

[0050] 85 parts of boehmite, 6 parts of iron oxide, 2 parts of titanium oxide, 2 parts of silicon oxide, 3 parts of starch, and 2 parts of polyvinyl alcohol (model 1788).

[0051] The preparation method of the above-mentioned deodorizing catalyst includes the following steps:

[0052] (1) After mixing boehmite, ferric oxide, titanium oxide and silicon oxide, the mixture is fully ball-milled in a ball mill and passed through a 200-mesh sieve to obtain inorganic powder;

[0053] (2) After mixing polyvinyl alcohol with 10 times its weight of water and allowing it to swell for 5 hours, it is then mixed with the inorganic powder obtained in step (1) and kneaded to form mud.

[0054] The mud was cut into 15mm cylindrical particles using a 4mm aperture extruder, dried at 80℃ for 8 hours, and then calcined at 550℃ for 5 hours to obtain a deodorizing catalyst.

[0055] Example 2

[0056] An odor-removing catalyst, comprising the following components by mass parts:

[0057] The composition consists of 86 parts boehmite, 4 parts iron oxide, 2.5 parts titanium dioxide, 1.5 parts silicon dioxide, 5 parts potato starch, and 1 part carboxymethyl cellulose.

[0058] The preparation method of the above-mentioned deodorizing catalyst includes the following steps:

[0059] (1) After mixing boehmite, ferric oxide, titanium oxide and silicon oxide, the mixture is fully ball-milled in a ball mill and passed through a 200-mesh sieve to obtain inorganic powder;

[0060] (2) Mix potato flour and carboxymethyl cellulose with 10 times their weight of water and let them swell for 4 hours. Then mix them with the inorganic powder obtained in step (1) and knead them to form mud.

[0061] The mud was cut into 12mm cylindrical particles using a 4mm aperture extruder, dried at 70℃ for 5 hours, and then calcined at 750℃ for 7 hours to obtain a deodorizing catalyst.

[0062] Example 3

[0063] An odor-removing catalyst, comprising the following components by mass parts:

[0064] The composition consists of 81 parts boehmite, 8 parts iron oxide, 2 parts titanium oxide, 2 parts silicon oxide, and 7 parts polyoxyethylene (molecular weight 600,000).

[0065] The preparation method of the above-mentioned deodorizing catalyst includes the following steps:

[0066] (1) After mixing boehmite, ferric oxide, titanium oxide and silicon oxide, the mixture is fully ball-milled in a ball mill and passed through a 200-mesh sieve to obtain inorganic powder;

[0067] (2) After mixing polyoxyethylene with 10 times its weight of water, it is fully swollen for 10 hours, and then mixed with the inorganic powder obtained in step (1) and kneaded to form mud.

[0068] The mud was cut into 15mm cylindrical particles using a 5mm aperture extruder, dried at 60℃ for 11 hours, and then calcined at 580℃ for 6 hours to obtain a deodorizing catalyst.

[0069] Example 4

[0070] An odor-removing catalyst, comprising the following components by mass parts:

[0071] The composition consists of 89 parts boehmite, 3 parts iron oxide, 2 parts titanium oxide, 1 part silicon oxide, and 5 parts starch ether.

[0072] The preparation method of the above-mentioned deodorizing catalyst includes the following steps:

[0073] (1) After mixing boehmite, ferric oxide, titanium oxide and silicon oxide, the mixture is fully ball-milled in a ball mill and passed through a 200-mesh sieve to obtain inorganic powder;

[0074] (2) Mix starch ether with 10 times its weight of water and let it swell for 4 hours. Then mix it with the inorganic powder obtained in step (1) and knead it to form mud.

[0075] The mud was cut into 15mm cylindrical particles using a 4mm aperture extruder, dried at 50℃ for 12 hours, and then calcined at 650℃ for 7 hours to obtain a deodorizing catalyst.

[0076] Comparative Example

[0077] A catalyst, by mass parts, has the following components:

[0078] 95 parts of pseudoboehmite and 5 parts of starch ether.

[0079] The preparation method of the above catalyst is as follows: Boehmite is fully ball-milled in a ball mill and passed through a 200-mesh sieve to obtain boehmite powder;

[0080] Starch ether was mixed with 10 times its weight to prepare a starch ether paste, which was then mixed with boehmite powder in a kneader to form a mud. The mud was then cut into 15mm cylindrical particles by an extruder with a diameter of 4mm. After being dried at 50℃ for 12 hours, the particles were calcined at 600℃ for 6 hours and then removed from the furnace to obtain the catalyst.

[0081] The deodorization effects of the deodorization catalysts prepared in Examples 1-4 and the catalysts prepared in the comparative examples were tested respectively. Specific steps included:

[0082] 200 kg of chicken feathers and 200 kg of water were placed in a 1 cubic meter pressure reactor, along with 2 kg of sodium carbonate. The reactor was heated in a jacket to 135–140°C and held for 3 hours. The odorous exhaust gas from the depressurized steam, after passing through a water-cooled tube condenser, was stored in a 200 L rubber bladder for later use. The corresponding catalyst was loosely piled in a 100 mm inner diameter quartz tube furnace, with a catalyst bed length of 80 cm. One end of the quartz tube furnace was connected to a 2 kW gas burner, and the flue gas heated the catalyst bed to 600°C. At 700℃, the odorous gas was connected to the same end of the flue gas tube furnace after passing through a gas flow meter. The valve was adjusted so that the gas residence time in the furnace reached about 0.8s. The tail gas was led out from the other end of the tube furnace through a gas pipe and discharged sequentially from a gas washing bottle containing 5 parts sodium carbonate aqueous solution and 5 parts sulfuric acid aqueous solution. The deodorization effect was evaluated using both subjective and objective methods. The subjective method used dimensionless olfaction identification, while the objective method used gas chromatography to detect the concentration of hydrogen sulfide and spectrophotometry to detect the concentration of ammonia and sulfur dioxide. The detection results are shown in Table 1 below.

[0083] Table 1. Comparison of deodorization effects of the deodorization catalysts prepared in Examples 1-4 and the catalysts prepared in the comparative examples.

[0084]

[0085]

[0086] Figure 1 The dimensionless bar graphs of odor identification after catalytic decomposition of malodorous gases generated during the preparation of feather protein powder by the deodorizing catalysts prepared in Examples 1-4 and the catalysts prepared in the comparative examples are shown.

[0087] Figure 2The graph shows the hydrogen sulfide concentration after the deodorizing catalysts prepared in Examples 1-4 and the catalysts prepared in the comparative examples catalyze the decomposition of malodorous gases generated during the preparation of feather protein powder.

[0088] In summary, compared with the comparative example, the deodorizing catalysts provided in the examples, which synergistically incorporate boehmite, iron oxide, titanium oxide, and silicon oxide, have a better catalytic decomposition effect on the malodorous gases generated during the preparation of feather protein powder. In particular, the deodorizing catalysts of Examples 1 and 2 significantly exceed the treatment effect of the simple boehmite catalyst component in Comparative Example 1. This is due to the synergistic catalytic effect of ferric oxide, titanium oxide, and silicon oxide under appropriate mass ratios.

[0089] Since the content of malodorous gas components in the exhaust gas generated by the high-temperature and high-pressure rendering of animal carcasses is much lower than that of the deodorizing catalyst generated during the feather protein powder processing, it can be seen that the deodorizing catalyst provided by the present invention has a more prominent deodorizing effect on the decomposition of malodorous gases in the exhaust gas generated by the treatment of animal carcasses.

[0090] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. Use of a deodorizing catalyst in eliminating malodorous gases in the processing of animal carcasses and feather meal production, characterized in that, The deodorization catalyst comprises the following components in terms of mass fraction: Pseudo-boehmite 80~90 parts, ferric oxide 3~8 parts, titanium oxide 1~3 parts, silicon oxide 1~3 parts, and organic pore-forming agent 4~8 parts; The preparation method of the deodorization catalyst comprises the following steps: (1) mixing pseudo-boehmite, ferric oxide, titanium oxide and silicon oxide, and then sequentially performing crushing and sieving to obtain inorganic powder; (2) mixing organic pore-forming agent and water to swell, and then mixing the inorganic powder obtained in the step (1) to obtain mud; sequentially performing molding, drying and calcination on the mud to obtain the deodorization catalyst.

2. Use according to claim 1, characterized in that, The deodorization catalyst comprises the following components in terms of mass fraction: Pseudo-boehmite 82~88 parts, ferric oxide 4~7 parts, titanium oxide 1.5~2.5 parts, silicon oxide 1.5~2.5 parts, and organic pore-forming agent 5~7 parts.

3. Use according to claim 1, characterized in that, The organic pore-forming agent is at least one of starch, polyvinyl alcohol, polyacrylamide, polyethylene oxide, deacetylated chitosan, sodium polyacrylate, cellulose hydrophilic derivative and starch hydrophilic derivative.

4. Use according to claim 1, characterized in that, The sieving in the step (1) is sieving through a 200~500 mesh sieve.

5. The use according to claim 1, characterized in that, The mass ratio of the organic pore-forming agent to water in the step (2) is 1: (8~14).

6. Use according to claim 1, characterized in that, The molding in the step (2) is molding into columnar particles with a diameter of 2~10 mm by using extrusion or shaking.

7. Use according to claim 1, characterized in that, The temperature of the drying in the step (2) is 50~120℃, and the time of the drying is 0.5~12 h.

8. The use according to claim 1, characterized in that, The temperature of the calcination in the step (2) is 500~800℃, and the time of the calcination is 4~12 h.

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