A method for catalytic degradation of organic waste

Abstract

The present invention provides a method for catalytic degradation of organic waste, which belongs to the technical field of organic waste degradation. The method for catalytic degradation of organic waste provided by the present invention comprises the following steps: under closed micro-oxygen conditions, mixing organic waste with a magnetic heat-conducting catalyst for catalytic degradation to obtain catalytic degradation gas, catalytic degradation suspended particulate matter, and catalytic degradation solid; the temperature of the catalytic degradation is 200-250°C, and the time of the catalytic degradation is 15-24 hours; the obtained catalytic degradation gas and catalytic degradation suspended particulate matter are purified and then discharged, and the obtained catalytic degradation solid is subjected to magnetic separation to obtain ash and recover the magnetic heat-conducting catalyst. The method for catalytic degradation of organic waste provided by the present invention can quickly achieve catalytic degradation of organic waste at a relatively low temperature, does not generate harmful substances such as dioxins, realizes on-site disposal of organic waste in daily life, and the method is simple, easy to operate, and low in cost.

Description

Technical Field

[0001] The present invention relates to the technical field of organic waste degradation, in particular to a method for catalytically degrading organic waste. Background Art

[0002] Currently, rural domestic waste disposal faces challenges due to incomplete infrastructure and high investment costs. Although a three-tiered waste collection and disposal model (village collection, township transfer, and county treatment) has been established, the existing waste collection and disposal model faces economic challenges due to the vast rural area and dispersed waste distribution, resulting in long transportation distances, large land requirements for treatment, high collection and transportation costs, and high infrastructure construction costs. From a social and environmental perspective, the indiscriminate dumping and accumulation of domestic waste, combined with the lack of timely removal, can easily lead to secondary pollution of the surrounding environment, including water, soil, and air, breeding mosquitoes and flies, creating foul odors, and seriously impacting the rural living environment while also posing a health risk to villagers. Regarding treatment technology, despite the construction of a 5t / d waste incineration facility, it is unable to operate properly due to the low transportation and collection costs and the low volume of waste generated. Landfilling consumes significant land resources and incurs high costs for leakage prevention and leachate treatment. Since the government still supports landfilling after volume reduction, direct landfilling of domestic waste is no longer suitable for my country's current social development.

[0003] Therefore, providing a method for catalytic degradation of organic waste that can achieve on-site disposal of organic waste in life without generating other pollution has become a difficult problem that needs to be solved urgently in this field. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for catalytic degradation of organic waste, which can quickly achieve catalytic degradation of organic waste at a relatively low temperature without generating harmful substances such as dioxins, thereby realizing on-site disposal of organic waste in daily life. The method is simple, easy to operate and low in cost.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for catalytic degradation of organic waste, comprising the following steps:

[0007] (1) Under closed micro-oxygen conditions, organic waste is mixed with a magnetic heat-conducting catalyst for catalytic degradation to obtain catalytic degradation gas, catalytic degradation suspended particulate matter, and catalytic degradation solids; the catalytic degradation temperature is 200 to 250° C., and the catalytic degradation time is 15 to 24 hours;

[0008] (2) The catalytic degradation gas and catalytic degradation suspended particulate matter obtained in step (1) are purified and then discharged, and the catalytic degradation solid obtained in step (1) is magnetically separated to obtain ash and recover the magnetic thermal conductive catalyst.

[0009] Preferably, the oxygen concentration of the enclosed micro-oxygen in step (1) is 0.01 to 0.1 mL / L.

[0010] Preferably, the mass ratio of the organic waste to the magnetic thermally conductive catalyst in step (1) is (90-110):(1-5).

[0011] Preferably, the organic waste in step (1) includes one or more of waste plastics, waste paper, kitchen waste, waste wood products and waste nylon materials.

[0012] Preferably, the magnetic thermally conductive catalyst in step (1) is a carbon-nitrogen doped Fe3O4-MgO catalyst.

[0013] Preferably, the preparation method of the carbon-nitrogen doped Fe3O4-MgO catalyst comprises the following steps:

[0014] 1) mixing an iron salt, a magnesium salt aqueous solution and a dicyandiamide aqueous solution and drying to obtain an iron-magnesium-dicyandiamide complex;

[0015] 2) calcining the iron-magnesium dicyandiamide complex obtained in step 1) to obtain a carbon-nitrogen doped Fe3O4-MgO catalyst.

[0016] Preferably, in step 1), the ratio of the mass of the iron salt to the total volume of the magnesium salt aqueous solution and the dicyandiamide aqueous solution is (0.05-0.15) g: (1-2) L.

[0017] Preferably, the calcination temperature in step 2) is 500-600° C., and the calcination time is 2.5-3.5 hours.

[0018] Preferably, the heating method for catalytic degradation in step (1) is light wave irradiation; the wavelength of the light wave irradiation is 170-180 nm, and the intensity of the light wave irradiation is 60-70 mW / m 2 .

[0019] Preferably, the purification of the degradation catalytic gas in step (2) includes sequentially performing water washing and spraying, electrostatic tar capture and low-temperature plasma treatment.

[0020] The method for catalytic degradation of organic waste provided by the present invention comprises the following steps: under closed micro-oxygen conditions, mixing organic waste with a magnetic thermally conductive catalyst for catalytic degradation to obtain catalytic degradation gas, catalytic degradation suspended particulate matter, and catalytic degradation solid; the catalytic degradation temperature is 200-250°C, and the catalytic degradation time is 15-24 hours; the obtained catalytic degradation gas and catalytic degradation suspended particulate matter are purified and then discharged, and the obtained catalytic degradation solid is subjected to magnetic separation to obtain ash and recover the magnetic thermally conductive catalyst. The present invention utilizes the catalytic action of the magnetic thermally conductive catalyst to activate H2O to form OH - Free radicals and oxygen free radicals can effectively promote the full progress of the decomposition reaction; at the same time, in a micro-oxygen environment and at a lower temperature, other side reactions will not cause the generation of harmful substances such as dioxins, and the magnetic thermal conductive catalyst also has a good thermal conductivity, which can effectively activate organic waste at a lower temperature of 200-250 ° C, accelerate the friction and collision between molecules, thereby realizing rapid, effective and harmless on-site treatment of organic waste. The method is simple and does not require long-distance transportation of rural garbage to specific urban garbage treatment stations, and the cost is low. In addition, the use of magnetic thermal conductive catalysts can utilize their magnetic characteristics to recycle them, thereby realizing the reuse of magnetic thermal conductive catalysts.

[0021] The results of the embodiment show that the ash reduction rate obtained by catalytically degrading organic waste using the method provided by the present invention is 2.6-2.8%, and when the final product is discharged, the pollutant content thereof is: suspended particulate matter = 18-25 mg / m 3 ; NO x =90~110mg / m 3 ; SO2=30~50mg / m 3 HCl ≤ 21 mg / m 3 CO = 70-80 mg / m 3 Hg and its compounds (in Hg) = 0.01-0.02 mg / m 3 Cadmium, thallium and their compounds (calculated as Cd+Tl) = 0.02-0.03 mg / m 3 Antimony, arsenic, lead, chromium, cobalt, copper, manganese, nickel and their compounds (calculated as Sb+As+Pb+Cr+Co+Cu+Mn+Ni) ≤ 0.2 mg / m 3 ; Dioxins = 0.001~0.03ngTEQ / m 3 The pollutant contents in the above catalytic degradation products all meet the emission standards of the "Pollution Control Standard for Incineration of Municipal Waste" (GB 18485-2014). DETAILED DESCRIPTION

[0022] The present invention provides a method for catalytic degradation of organic waste, comprising the following steps:

[0023] (1) Under closed micro-oxygen conditions, organic waste is mixed with a magnetic heat-conducting catalyst for catalytic degradation to obtain catalytic degradation gas, catalytic degradation suspended particulate matter, and catalytic degradation solids; the catalytic degradation temperature is 200 to 250° C., and the catalytic degradation time is 15 to 24 hours;

[0024] (2) The catalytic degradation gas and catalytic degradation suspended particulate matter obtained in step (1) are purified and then discharged, and the catalytic degradation solid obtained in step (1) is magnetically separated to obtain ash and recover the magnetic thermal conductive catalyst.

[0025] The invention mixes organic waste with a magnetic heat-conducting catalyst under a closed micro-oxygen condition to carry out catalytic degradation, thereby obtaining catalytic degradation gas, catalytic degradation suspended particulate matter and catalytic degradation solid.

[0026] In the present invention, the oxygen concentration of the enclosed micro-oxygen chamber is preferably 0.01 to 0.1 mL / L, more preferably 0.03 to 0.08 mL / L. By controlling the oxygen concentration of the enclosed micro-oxygen chamber within the above range, the present invention can oxidize organic macromolecules in organic waste, breaking their carbon chains to form small molecules, which are more conducive to their full decomposition.

[0027] In the present invention, the mass ratio of the organic waste to the magnetic thermally conductive catalyst is preferably (90-110):(1-5), and more preferably (95-105):(2-4). By controlling the amount of the magnetic thermally conductive catalyst within the above range, the present invention can ensure sufficient contact between the organic waste and the magnetic thermally conductive catalyst, thereby achieving catalytic degradation of the organic waste.

[0028] In the present invention, the organic waste preferably includes one or more of waste plastics, waste paper, kitchen waste, waste wood products and waste nylon materials.

[0029] In the present invention, the magnetic thermally conductive catalyst is preferably a carbon-nitrogen-doped Fe3O4-MgO catalyst. By using the carbon-nitrogen-doped Fe3O4-MgO catalyst, the Fe3O4 in the catalyst imparts magnetic properties, enabling the recovery and reuse of the magnetic thermally conductive catalyst, further reducing costs and contributing to environmental protection. Furthermore, the carbon-nitrogen-doped Fe3O4-MgO catalyst also has a certain degree of thermal conductivity, enabling it to transfer heat within organic waste at relatively low temperatures, thereby achieving rapid degradation of the organic waste.

[0030] In the present invention, the preparation method of the carbon-nitrogen doped Fe3O4-MgO catalyst preferably comprises the following steps:

[0031] 1) mixing an iron salt, a magnesium salt aqueous solution and a dicyandiamide aqueous solution and drying to obtain an iron-magnesium-dicyandiamide complex;

[0032] 2) calcining the iron-magnesium dicyandiamide complex obtained in step 1) to obtain a carbon-nitrogen doped Fe3O4-MgO catalyst.

[0033] The invention mixes an iron salt, a magnesium salt aqueous solution and a dicyandiamide aqueous solution and then dries the mixture to obtain an iron-magnesium-dicyandiamide complex.

[0034] In the present invention, the iron salt is preferably a mixture of Fe(NO3)2 and Fe(NO3)3.

[0035] In the present invention, the method for preparing the mixture of Fe(NO3)2 and Fe(NO3)3 preferably comprises: mixing an aqueous solution of Fe(NO3)2 and an aqueous solution of Fe(NO3)3, and then performing ultrasonic treatment and drying in sequence to obtain a mixture of Fe(NO3)2 and Fe(NO3)3. The present invention has no special requirements for the specific operations of the mixing, ultrasonic treatment and drying, and conventional methods in the art can be used. The present invention obtains a mixture of Fe(NO3)2 and Fe(NO3)3 by adopting the above preparation method, which can ensure that Fe 2+ and Fe 3+ Even mixing is more conducive to obtaining a magnetic thermally conductive catalyst with good catalytic performance, ensuring that organic waste can be fully catalytically degraded.

[0036] In the present invention, the concentration of the Fe(NO3)2 aqueous solution is preferably 0.05-0.15 mol / L, more preferably 0.1 mol / L; the concentration of the Fe(NO3)3 aqueous solution is preferably 0.05-0.15 mol / L, more preferably 0.1 mol / L. In the present invention, the volume ratio of the Fe(NO3)2 aqueous solution to the Fe(NO3)3 aqueous solution is preferably 2:(3-5). The present invention can make Fe(NO3)2 aqueous solution and Fe(NO3)3 aqueous solution have a volume ratio of 2:(3-5) by controlling the concentration of each of the Fe(NO3)2 aqueous solution and the Fe(NO3)3 aqueous solution and the volume ratio of the two within the above range. 2+ and Fe 3+ Having a suitable ratio to obtain Fe3O4 is more conducive to obtaining a magnetic thermally conductive catalyst with good catalytic performance, ensuring that organic waste can be fully catalytically degraded.

[0037] In the present invention, the magnesium salt aqueous solution is preferably a Mg(NO3)2 aqueous solution; the concentration of the Mg(NO3)2 aqueous solution is preferably 0.1 to 0.3 mol / L, more preferably 0.2 mol / L. In the present invention, the concentration of the dicyandiamide aqueous solution is preferably 0.05 to 0.15 mol / L, more preferably 0.1 mol / L. In the present invention, the volume ratio of the Mg(NO3)2 aqueous solution to the dicyandiamide aqueous solution is preferably 1:(3 to 5). The present invention can make the Mg(NO3)2 aqueous solution and the dicyandiamide aqueous solution have a volume ratio of 1:(3 to 5) by controlling the concentrations of the magnesium salt aqueous solution and the dicyandiamide aqueous solution and the volume ratio of the two within the above range. 2+ Having a suitable ratio with dicyandiamide is more conducive to obtaining a magnetic thermal conductive catalyst with good catalytic performance, ensuring that organic waste can be fully catalytically degraded.

[0038] In the present invention, the ratio of the mass of the iron salt to the total volume of the magnesium salt aqueous solution and the dicyandiamide aqueous solution is (0.05-0.15) g: (1-2) L. By controlling the ratio of the mass of the iron salt to the total volume of the magnesium salt aqueous solution and the dicyandiamide aqueous solution within the above range, the present invention can ensure that the Mg, carbon, and nitrogen in the magnetic thermally conductive catalyst have a suitable doping ratio, thereby ensuring that the magnetic thermally conductive catalyst has an excellent catalytic effect and is more conducive to achieving sufficient catalytic degradation of organic waste.

[0039] In the present invention, the mixing operation is preferably stirring. The present invention has no special requirements on the specific parameters of the stirring, as long as the various raw materials can be uniformly mixed.

[0040] In the present invention, the drying method is preferably to stir in an oil bath at 85°C until the water evaporates. 2+ 、Fe 3+ and Mg 2+ It is evenly complexed on the dicyandiamide molecules to form a uniform iron-magnesium dicyandiamide complex, which is more conducive to uniformly doping Mg and carbon and nitrogen in Fe3O4, effectively improving the catalytic effect of the magnetic thermal conductive catalyst and ensuring that organic waste can be fully catalytically degraded.

[0041] After obtaining the iron-magnesium-dicyandiamide complex, the present invention preferably calcines the iron-magnesium-dicyandiamide complex to obtain a carbon-nitrogen doped Fe3O4-MgO catalyst.

[0042] In the present invention, the calcination temperature is preferably 500-600°C, more preferably 550°C; the calcination time is preferably 2.5-3.5h, more preferably 2h. By controlling the calcination temperature and time within the above ranges, the dicyandiamide can be fully decomposed to form a carbon-nitrogen skeleton, while Fe 2+ 、Fe 3+ and Mg 2+Fully converted into Fe3O4 and MgO.

[0043] In the present invention, the calcination atmosphere is preferably a vacuum atmosphere. By calcining in a vacuum atmosphere, the present invention can avoid oxidation of C and N in dicyandiamide, while ensuring that the oxygen in the nitrate in the iron salt and magnesium salt can combine with the metal and be converted into Fe3O4 and MgO.

[0044] In the present invention, the temperature of the catalytic degradation is 200-250°C, preferably 210-240°C; the time of the catalytic degradation is 15-24h, preferably 16-23h. By controlling the temperature of the catalytic degradation within the above range, the present invention can activate organic waste, accelerate the friction and collision between molecules, and activate H2O under the action of the magnetic thermal conductive catalyst to form OH - Free radicals and oxygen free radicals effectively promote the full decomposition reaction, thereby achieving rapid, effective and harmless on-site treatment of organic waste.

[0045] In the present invention, the heating method for catalytic degradation is preferably light wave irradiation. In the present invention, the wavelength of the light wave irradiation is preferably 170 to 180 nm; the intensity of the light wave irradiation is preferably 60 to 70 mW / m 2 , more preferably 65mW / m 2 . In the present invention, light wave irradiation is stopped after the temperature of catalytic degradation is reached under light wave irradiation, and light wave irradiation is automatically started after the temperature is lower than the temperature of catalytic degradation. The present invention heats by light wave irradiation. On the one hand, the magnetic heat-conductive catalyst can absorb the nanowaves emitted by the light wave, and quickly transfer the heat to the inside of the organic waste, thereby accelerating the catalytic degradation of the organic waste; on the other hand, the catalytic degradation temperature can be more conveniently controlled to be constant, ensuring that the catalytic degradation reaction continues, so that the organic waste is fully catalytically degraded, and providing a heat source by light wave irradiation is more environmentally friendly.

[0046] After obtaining catalytic degradation gas, catalytic degradation suspended particulate matter and catalytic degradation solid, the present invention purifies the obtained catalytic degradation gas and catalytic degradation suspended particulate matter before discharging, and magnetically separates the obtained catalytic degradation solid to obtain ash and recover the magnetic thermal conductive catalyst.

[0047] In the present invention, the degradation catalytic gas preferably includes water, CO, CO2, NO x , SO2, HCl and tar gas.

[0048] In the present invention, the purification of the catalytic degradation gas preferably includes sequentially performing water washing and spraying, electrostatic tar capture, and low-temperature plasma treatment. The present invention has no special requirements for each of the above purification operations; conventional operations in the art can be used to ensure effective purification of the catalytic degradation gas to meet emission standards.

[0049] In the present invention, the catalytic degradation solid preferably includes ash and a magnetic thermally conductive catalyst.

[0050] The present invention has no special requirements for the operation of magnetic separation of the magnetic thermally conductive catalyst. The magnetic separation operation well known in the art can be used to recover the magnetic thermally conductive catalyst.

[0051] The method for catalytic degradation of organic waste provided by the present invention can quickly achieve catalytic degradation of organic waste at a relatively low temperature, without generating harmful substances such as dioxins, thereby realizing on-site disposal of organic waste in daily life. The method is simple and easy to operate, and there is no need to transport rural waste over long distances to specific urban waste treatment stations, which is low in cost. In addition, the use of a magnetic thermally conductive catalyst can utilize its magnetic characteristics to recycle it, thereby realizing the reuse of the magnetic thermally conductive catalyst.

[0052] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0053] Example 1

[0054] A method for catalytic degradation of organic waste, comprising the following steps:

[0055] (1) Under closed micro-oxygen conditions, organic waste is mixed with a magnetic heat-conducting catalyst for catalytic degradation to obtain catalytic degradation gas, catalytic degradation suspended particulate matter, and catalytic degradation solids;

[0056] The oxygen concentration of the enclosed micro-oxygen chamber is 0.03 ml / L; the mass ratio of the organic waste to the magnetic thermal conductive catalyst is 110:1; the organic waste is waste plastic, waste paper and waste nylon; and the magnetic thermal conductive catalyst is a carbon-nitrogen doped Fe3O4-MgO catalyst.

[0057] The preparation method of the carbon-nitrogen doped Fe3O4-MgO catalyst comprises the following steps:

[0058] 1) Mixing iron salt powder, magnesium salt aqueous solution and dicyandiamide aqueous solution and drying them to obtain an iron-magnesium-dicyandiamide complex; specifically: Fe(NO3)2 aqueous solution and Fe(NO3)3 aqueous solution are mixed, ultrasonically treated for 30 minutes and dried in an oven at 105°C to obtain a mixture of 0.1 mol / L Fe(NO3)2 and 0.1 mol / LFe(NO3)3, i.e., iron salt powder; wherein the volume ratio of the Fe(NO3)2 aqueous solution to the Fe(NO3)3 aqueous solution is 2:3; the magnesium salt aqueous solution is a 0.2 mol / LMg(NO3)2 aqueous solution; the concentration of the dicyandiamide aqueous solution is 0.1 mol / L; the volume ratio of the Mg(NO3)2 aqueous solution to the dicyandiamide aqueous solution is 1:5; the ratio of the mass of the iron salt powder to the total volume of the magnesium salt aqueous solution and the dicyandiamide aqueous solution is 0.1 g:1 L; the mixing operation is stirring; and the drying method is stirring in an 85°C oil bath until the water is evaporated.

[0059] 2) calcining the iron-magnesium dicyandiamide complex obtained in step 1) to obtain a carbon-nitrogen-doped Fe3O4-MgO catalyst; the calcination temperature is 550° C. and the time is 3 hours.

[0060] The temperature of the catalytic degradation is 200°C, and the time of the catalytic degradation is 18 hours. The heating method of the catalytic degradation is light wave irradiation. When the temperature of the catalytic degradation is reached under light wave irradiation, the light wave irradiation is stopped, and when the temperature is lower than the temperature of the catalytic degradation, the light wave irradiation is automatically started. The wavelength of the light wave irradiation is 180nm, and the intensity of the light wave irradiation is 65mW / m 2 ;

[0061] (2) purifying the catalytic degradation gas and catalytic degradation suspended particulate matter obtained in step (1) and then discharging them, and magnetically separating the catalytic degradation solid obtained in step (1) to obtain ash and recover the magnetic thermal conductive catalyst; wherein the degradation catalytic gas is water, CO, CO2, NO x , SO2 and tar gas; the catalytic degradation solid is ash and magnetic thermal conductive catalyst; the purification of the degradation catalytic gas is carried out in sequence by water washing spraying, electric tar capture and low-temperature plasma treatment.

[0062] Example 2

[0063] A method for catalytic degradation of organic waste, comprising the following steps:

[0064] (1) Under closed micro-oxygen conditions, organic waste is mixed with a magnetic heat-conducting catalyst for catalytic degradation to obtain catalytic degradation gas, catalytic degradation suspended particulate matter, and catalytic degradation solids;

[0065] The oxygen concentration of the enclosed micro-oxygen chamber is 0.08 ml / L; the mass ratio of the organic waste to the magnetic thermally conductive catalyst is 95:1; the organic waste is waste plastics and kitchen waste;

[0066] The magnetic thermally conductive catalyst is a carbon-nitrogen doped Fe3O4-MgO catalyst;

[0067] The preparation method of the carbon-nitrogen doped Fe3O4-MgO catalyst comprises the following steps:

[0068] 1) Mixing iron salt powder, magnesium salt aqueous solution and dicyandiamide aqueous solution and drying them to obtain an iron-magnesium-dicyandiamide complex; specifically: Fe(NO3)2 aqueous solution and Fe(NO3)3 aqueous solution are mixed, ultrasonically treated for 30 minutes and dried in an oven at 105°C to obtain a mixture of 0.1 mol / L Fe(NO3)2 and 0.1 mol / LFe(NO3)3, i.e., iron salt powder; wherein the volume ratio of the Fe(NO3)2 aqueous solution to the Fe(NO3)3 aqueous solution is 1:2; the magnesium salt aqueous solution is a 0.2 mol / LMg(NO3)2 aqueous solution; the concentration of the dicyandiamide aqueous solution is 0.1 mol / L; the volume ratio of the Mg(NO3)2 aqueous solution to the dicyandiamide aqueous solution is 2:5; the ratio of the mass of the iron salt powder to the total volume of the magnesium salt aqueous solution and the dicyandiamide aqueous solution is 0.1 g:1.5 L; the mixing operation is stirring; and the drying method is stirring in an 85°C oil bath until the water is evaporated.

[0069] 2) calcining the iron-magnesium dicyandiamide complex obtained in step 1) to obtain a carbon-nitrogen-doped Fe3O4-MgO catalyst; the calcination temperature is 550° C. and the time is 3 hours.

[0070] The temperature of the catalytic degradation is 220°C, and the time of the catalytic degradation is 21 hours. The heating method of the catalytic degradation is light wave irradiation. When the temperature of the catalytic degradation is reached under light wave irradiation, the light wave irradiation is stopped, and when the temperature is lower than the temperature of the catalytic degradation, the light wave irradiation is automatically started. The wavelength of the light wave irradiation is 170nm, and the intensity of the light wave irradiation is 65mW / m 2 ;

[0071] (2) purifying the catalytic degradation gas and catalytic degradation suspended particulate matter obtained in step (1) and then discharging them, and magnetically separating the catalytic degradation solid obtained in step (1) to obtain ash and recover the magnetic thermal conductive catalyst; wherein the degradation catalytic gas is water, CO, CO2, NO x , SO2 and tar gas; the catalytic degradation solids are ash and magnetic thermal conductive catalyst; the purification of the degradation catalytic gas is carried out in sequence by water washing spraying, electric capture of tar and low-temperature plasma treatment; the recovery of the magnetic thermal conductive catalyst is magnetic separation recovery.

[0072] Example 3

[0073] A method for catalytic degradation of organic waste, comprising the following steps:

[0074] (1) Under the conditions of closed micro-oxygen and light wave irradiation, organic waste is mixed with a magnetic heat-conducting catalyst for catalytic degradation to obtain catalytic degradation gas, catalytic degradation suspended particulate matter, and catalytic degradation solids;

[0075] The oxygen concentration of the enclosed micro-oxygen chamber is 0.08 ml / L; the mass ratio of the organic waste to the magnetic thermal conductive catalyst is 100:3; the organic waste is waste plastic, waste paper, kitchen waste, waste wood products and waste nylon materials; and the magnetic thermal conductive catalyst is a carbon-nitrogen doped Fe3O4-MgO catalyst.

[0076] The preparation method of the carbon-nitrogen doped Fe3O4-MgO catalyst comprises the following steps:

[0077] 1) Mixing iron salt powder, magnesium salt aqueous solution and dicyandiamide aqueous solution and drying them to obtain an iron-magnesium-dicyandiamide complex; specifically: Fe(NO3)2 aqueous solution and Fe(NO3)3 aqueous solution are mixed, ultrasonically treated for 30 minutes and dried in an oven at 105°C to obtain a mixture of 0.1 mol / L Fe(NO3)2 and 0.1 mol / LFe(NO3)3, i.e., iron salt powder; wherein the volume ratio of the Fe(NO3)2 aqueous solution to the Fe(NO3)3 aqueous solution is 1:2; the magnesium salt aqueous solution is a 0.2 mol / LMg(NO3)2 aqueous solution; the concentration of the dicyandiamide aqueous solution is 0.1 mol / L; the volume ratio of the Mg(NO3)2 aqueous solution to the dicyandiamide aqueous solution is 2:5; the ratio of the mass of the iron salt powder to the total volume of the magnesium salt aqueous solution and the dicyandiamide aqueous solution is 0.1 g:1.5 L; the mixing operation is stirring; and the drying method is stirring in an 85°C oil bath until the water is evaporated.

[0078] 2) calcining the iron-magnesium dicyandiamide complex obtained in step 1) to obtain a carbon-nitrogen-doped Fe3O4-MgO catalyst; the calcination temperature is 550° C. and the time is 3 hours.

[0079] The temperature of the catalytic degradation is 230°C, and the time of the catalytic degradation is 23 hours. The heating method of the catalytic degradation is light wave irradiation. When the temperature of the catalytic degradation is reached under light wave irradiation, the light wave irradiation is stopped, and when the temperature is lower than the temperature of the catalytic degradation, the light wave irradiation is automatically started. The wavelength of the light wave irradiation is 180nm, and the intensity of the light wave irradiation is 65mW / m 2 ;

[0080] (2) purifying the catalytic degradation gas and catalytic degradation suspended particulate matter obtained in step (1) and then discharging them, and magnetically separating the catalytic degradation solid obtained in step (1) to obtain ash and recover the magnetic thermal conductive catalyst; wherein the degradation catalytic gas is water, CO, CO2, NO x , SO2 and tar gas; the catalytic degradation solids are ash and magnetic thermal conductive catalyst; the purification of the degradation catalytic gas is carried out in sequence by water washing spraying, electric capture of tar and low-temperature plasma treatment; the recovery of the magnetic thermal conductive catalyst is magnetic separation recovery.

[0081] The emission standards of the catalytic degradation gas, catalytic degradation particulate matter, and ash in the catalytic degradation solid in Examples 1 to 3 were tested in accordance with the "Standard for Pollution Control of Municipal Waste Incineration" (GB 18485-2014). The test results of the pollutant content in the catalytic degradation products in Examples 1 to 3 are shown in Table 1.

[0082] Table 1 Test results of pollutant content in catalytic degradation products in Examples 1 to 3

[0083]

[0084] As can be seen from Table 1, the ash reduction rate obtained by catalytically degrading organic waste using the method provided by the present invention is 2.6-2.8%, and when the final product is discharged, the pollutant content thereof is: suspended particulate matter = 18-25 mg / m 3 ; NO x =90~110mg / m 3 ; SO2=30~50mg / m 3 HCl ≤ 21 mg / m 3 CO = 70-80 mg / m 3 Hg and its compounds (in Hg) = 0.01-0.02 mg / m 3 Cadmium, thallium and their compounds (calculated as Cd+Tl) = 0.02-0.03 mg / m 3 Antimony, arsenic, lead, chromium, cobalt, copper, manganese, nickel and their compounds (calculated as Sb+As+Pb+Cr+Co+Cu+Mn+Ni) ≤ 0.2 mg / m 3 ; Dioxins = 0.001~0.03ngTEQ / m 3 The pollutant contents in the above catalytic degradation products all meet the emission standards of the "Pollution Control Standard for Incineration of Municipal Waste" (GB 18485-2014).

[0085] In summary, the method for catalytic degradation of organic waste provided by the present invention can quickly achieve catalytic degradation of organic waste at a relatively low temperature without generating harmful substances such as dioxins, thereby realizing on-site disposal of organic waste in daily life. The method is simple, easy to operate and low in cost.

[0086] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for catalytic degradation of organic waste, characterized in that: The following steps are involved: (1) Under closed micro-oxygen conditions, organic waste is mixed with a magnetic heat-conducting catalyst for catalytic degradation to obtain catalytic degradation gas, catalytic degradation suspended particulate matter, and catalytic degradation solids; the catalytic degradation temperature is 200-250° C., and the catalytic degradation time is 15-24 hours; (2) purifying the catalytically degraded gas and catalytically degraded suspended particulate matter obtained in step (1) and then discharging them, and magnetically separating the catalytically degraded solid obtained in step (1) to obtain ash and recover the magnetic thermally conductive catalyst; The oxygen concentration of the enclosed micro-oxygen in step (1) is 0.01~0.1mL / L; In the step (1), the mass ratio of the organic waste to the magnetic thermally conductive catalyst is (90-110): (1-5); The magnetic thermally conductive catalyst in step (1) is a carbon-nitrogen doped Fe3O4-MgO catalyst; The preparation method of the carbon-nitrogen doped Fe3O4-MgO catalyst comprises the following steps: a) drying after mixing iron salt, magnesium salt aqueous solution and dicyandiamide aqueous solution to obtain iron-magnesium-dicyandiamide complex; b) the iron-magnesium dicyandiamide complex obtained in step a) was calcined to obtain a carbon-nitrogen-doped Fe3O4-MgO catalyst; The ratio of the mass of the iron salt to the total volume of the magnesium salt aqueous solution and the dicyandiamide aqueous solution in step a) is (0.05-0.15) g: (1-2) L.

2. The method according to claim 1, wherein The organic waste in step (1) includes one or more of waste plastics, waste paper, kitchen waste and waste wood products.

3. The method according to claim 1, wherein The calcination temperature in step b) is 500-600° C., and the calcination time is 2.5-3.5 hours.

4. The method according to claim 1, wherein The heating method for catalytic degradation in step (1) is light wave irradiation; the wavelength of the light wave irradiation is 170-180 nm, and the intensity of the light wave irradiation is 60-70 mW / m 2 .

5. The method according to claim 1, wherein The purification of the degradation catalytic gas in step (2) includes sequentially performing water washing and spraying, electric tar capture and low-temperature plasma treatment.

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