A method for treating light-cured waste by coupling photo-oxidation and catalytic pyrolysis

Abstract

The present invention relates to the technical field of preparing fuel oil by pyrolysis of photocured waste, and in particular to a method for treating photocured waste by coupling photooxidation and catalytic pyrolysis. The method comprises the following steps: firstly subjecting the photocured waste to photooxidation treatment, and then subjecting the photocured waste to catalytic pyrolysis after the photooxidation treatment; the photooxidation treatment specifically comprises irradiating the photocured waste with ultraviolet light under air conditions. The present invention provides a method for treating photocured waste by coupling photooxidation and catalytic pyrolysis, which can significantly increase the yield of aromatic products in pyrolysis oil by first subjecting the photocured waste to photooxidation treatment, and then subjecting the photocured waste to catalytic pyrolysis after the photooxidation treatment, thereby improving the quality of pyrolysis oil.

Description

Technical Field

[0001] The invention relates to the technical field of preparing fuel oil by pyrolysis of photocured waste, and in particular to a method for treating photocured waste by coupling photo-oxidation and catalytic pyrolysis. Background Art

[0002] Liquid photosensitive resin is cured by light and stacked layer by layer to generate a three-dimensional entity. It has been widely used in various industries. Solid waste, namely photocuring waste, is inevitably generated during its production and use. As a new type of organic solid waste, its production will increase dramatically in many application scenarios in the future. However, there is no targeted disposal technology at present. It is only incinerated or landfilled with urban domestic waste, which will cause a certain degree of harm to the environment and waste resources.

[0003] Pyrolysis has been proven to be an environmentally friendly way to dispose of photocured waste. It can effectively treat large amounts of waste while producing as few harmful pollutants as possible, and produce high-value chemicals such as pyrolysis oil and pyrolysis gas. However, due to the solid network structure of photocured waste, the energy required for its pyrolysis is relatively high. At the same time, there are the disadvantages of high oxygen content in pyrolysis oil and complex products that are difficult to separate, making its direct use value low.

[0004] At present, a large number of studies have shown that the use of catalytic pyrolysis can effectively convert waste plastics into commercial pyrolysis oil, such as aromatic hydrocarbon-rich oil technology, which is a promising means of resource utilization of waste plastics. However, the current use of catalytic pyrolysis to dispose of photocured waste still has the problem of low aromatic hydrocarbon yield and energy consumption that needs to be further reduced. Summary of the invention

[0005] The purpose of the present invention is to provide a method for treating photocured waste by coupling photooxidation and catalytic pyrolysis to solve the problems existing in the above-mentioned prior art. The yield of aromatics in pyrolysis oil is improved by coupling photooxidation and catalytic pyrolysis technology, and the energy consumption of catalytic pyrolysis is further reduced.

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

[0007] One of the technical solutions of the present invention is a method for treating photocured waste by coupling photooxidation and catalytic pyrolysis, comprising the following steps: firstly subjecting the photocured waste to photooxidation treatment, and then subjecting the photocured waste to catalytic pyrolysis after the photooxidation treatment; the photooxidation treatment specifically comprises irradiating the photocured waste with ultraviolet light under air conditions.

[0008] Furthermore, the wavelength of the ultraviolet light is 254-405 nm, preferably 365 nm.

[0009] The wavelength of ultraviolet light has a certain influence on the yield of aromatic products in the prepared pyrolysis oil. If it is lower or higher than the wavelength range recorded above, the photoinitiator will be insensitive to it, which is not conducive to the occurrence of oxidation reaction, the improvement of pyrolysis oil quality and the removal of photoinitiator. Therefore, the present invention preferably limits the wavelength of ultraviolet light to 254-405nm.

[0010] Furthermore, the irradiation power is 6-85W, and the time is 12h-288h, preferably 6W, and the time is 24h.

[0011] The power and duration of ultraviolet irradiation have a certain influence on the yield of aromatic products in the prepared pyrolysis oil. A power range or a time range lower than or higher than the above-mentioned power range and a time range will reduce the yield of aromatic products in the pyrolysis oil. Therefore, the present invention limits the irradiation power to 6-85W and the time to 12-288h.

[0012] Furthermore, the photo-cured waste further comprises a step of grinding into 80 mesh powder before the photo-oxidation treatment.

[0013] Furthermore, the catalytic pyrolysis uses a molecular sieve catalyst; the molecular sieve catalyst includes but is not limited to molecular sieves such as ZSM-5, HY, and Hβ.

[0014] The type of catalyst has a certain influence on the yield of aromatic products in pyrolysis oil (i.e., the quality of pyrolysis oil). When other commonly used catalysts in the field, such as nano-magnesium oxide and nano-aluminum oxide, are selected, the yield of aromatic products in pyrolysis oil prepared is significantly lower than that of molecular sieve catalysts.

[0015] Furthermore, the catalytic pyrolysis temperature is 400°C-700°C, and the time is 10-30 min; preferably 600°C, 30 min.

[0016] Furthermore, in the catalytic pyrolysis process, the photo-cured waste after photo-oxidation treatment and the catalyst are first mixed evenly in a mass ratio of 1:1 to obtain a mixed sample, and then the same mass of catalyst (i.e., the mass ratio of the amount of catalyst to the photo-cured waste after photo-oxidation pretreatment is 1:1) is taken to cover the surface of the mixed sample for catalytic pyrolysis.

[0017] The purpose of dividing the catalyst into two parts, one part is fully mixed with the photocured waste, and the other part is covered on the surface of the mixed sample in order to be able to efficiently and fully utilize the catalyst.

[0018] The second technical solution of the present invention is a method for improving the quality of pyrolysis oil prepared by catalytic pyrolysis of photocured waste, which adopts the above-mentioned method of coupling photo-oxidation and catalytic pyrolysis to treat photocured waste.

[0019] The third technical solution of the present invention is a method for reducing the energy consumption of preparing pyrolysis oil by pyrolysis of photocured waste, which adopts the above-mentioned method of coupling photo-oxidation and catalytic pyrolysis to treat photocured waste.

[0020] Technical concept of the present invention:

[0021] The present invention believes that the current catalytic pyrolysis of photocured waste still has the disadvantages of low aromatics yield and high energy consumption. At the same time, considering that there are harmful photoinitiators in the composition of photocured waste that are not bound or weakly bound to the polymer chain, they cannot be removed by pyrolysis or catalytic pyrolysis. The present invention is based on the fact that photoinitiators can serve as chromogenic groups that initiate photooxidation reactions. By treating photocured waste through photooxidation, harmful photoinitiators in photocured waste can be effectively removed, thereby reducing subsequent pyrolysis energy consumption, affecting the composition of pyrolysis products, and improving the quality of pyrolysis oil. After a series of preliminary studies, the present invention found that the coupled treatment of photooxidation and catalytic pyrolysis significantly improves the yield of aromatics in pyrolysis oil compared to direct catalytic pyrolysis of photocured waste.

[0022] The present invention discloses the following technical effects:

[0023] The present invention provides a method for treating photocured waste by coupling photooxidation with catalytic pyrolysis. The method can significantly increase the yield of aromatic products in pyrolysis oil by photooxidation treatment and improve the quality of pyrolysis oil by first photooxidation treatment of the photocured waste and then catalytic pyrolysis of the photocured waste after the photooxidation treatment. DETAILED DESCRIPTION

[0024] 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 should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0026] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation 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 a conflict with any incorporated document, the content of this specification shall prevail.

[0027] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0028] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0029] The ZSM-5 molecular sieve catalyst used in the present invention is as follows: cation type: H, sodium peroxide (wt%): 0.05, silica / alumina: 36, surface area (m 2 / g):350.

[0030] Unless otherwise specified, the raw materials used in the embodiments of the present invention can be obtained through commercial channels.

[0031] The photocurable waste powder used in the embodiment of the present invention is: photocurable waste prepared by printing Clearresin resin using a Formlabs Form3 printer, and ground into 80-mesh powder using a pulverizer.

[0032] Example 1

[0033] The light-cured waste powder was pyrolyzed in a slide rail tube furnace at a pyrolysis temperature of 600°C and a residence time of 30 minutes. The pyrolysis oil was collected by flushing the pipeline with dichloromethane, and the dichloromethane was evaporated using a rotary evaporator. The composition of the pyrolysis oil was obtained using GC-MS analysis software, and the aromatic yield was 9.96%.

[0034] Example 2

[0035] Take the light-cured waste powder and catalyst (ZSM-5), mix them evenly in a ratio of 1:1, take the same mass of catalyst to cover the surface of the above mixture, and pyrolyze in a slide rail tube furnace, the pyrolysis temperature is 600℃, and the residence time is 30min. Use dichloromethane to flush the pipeline to collect the pyrolysis oil, and use a rotary evaporator to evaporate the dichloromethane. Use GC-MS analysis software to obtain the composition of the pyrolysis oil, among which the aromatic yield is 26.88%.

[0036] Example 3

[0037] The light-cured waste powder was irradiated for 24 hours at a wavelength of 365nm and a power of 6W for photo-oxidation treatment.

[0038] The powder sample after photo-oxidation treatment was pyrolyzed in a slide rail tube furnace at a pyrolysis temperature of 600°C and a residence time of 30 min. The pyrolysis oil was collected by flushing the pipeline with dichloromethane, and the dichloromethane was evaporated using a rotary evaporator. The composition of the pyrolysis oil was obtained using GC-MS analysis software, and the aromatic yield was 28.59%.

[0039] Example 4

[0040] The light-cured powder was irradiated for 24 hours at a wavelength of 365 nm and a power of 6 W for photo-oxidation treatment.

[0041] Take the photocurable powder and catalyst (ZSM-5) after photooxidation treatment, mix them evenly in a ratio of 1:1, take the same mass of catalyst to cover the surface of the above mixture, and pyrolyze in a slide rail tube furnace, the pyrolysis temperature is 600℃, and the residence time is 30min. Use dichloromethane to flush the pipeline to collect the pyrolysis oil, and use a rotary evaporator to evaporate the dichloromethane. Use GC-MS analysis software to obtain the composition of the pyrolysis oil, of which the aromatic yield is 65.42%.

[0042] Example 5

[0043] The light-cured powder was irradiated for 24 hours at a wavelength of 405 nm and a power of 6 W for photo-oxidation treatment.

[0044] The powder sample after photo-oxidation treatment was pyrolyzed in a slide rail tube furnace at a pyrolysis temperature of 600°C and a residence time of 30 min. The pyrolysis oil was collected by flushing the pipeline with dichloromethane, and the dichloromethane was evaporated using a rotary evaporator. The composition of the pyrolysis oil was obtained using GC-MS analysis software, and the aromatic yield was 11.53%.

[0045] Example 6

[0046] The light-cured powder was irradiated for 24 hours at a wavelength of 405 nm and a power of 6 W for photo-oxidation treatment.

[0047] Take the photocurable powder after photo-oxidation treatment and the catalyst (ZSM-5), mix them evenly in a ratio of 1:1, take the same mass of catalyst to cover the surface of the above mixture, and pyrolyze in a slide rail tube furnace, the pyrolysis temperature is 600℃, and the residence time is 30min. Use dichloromethane to flush the pipeline to collect the pyrolysis oil, and use a rotary evaporator to evaporate the dichloromethane. Use GC-MS analysis software to obtain the composition of the pyrolysis oil, of which the aromatic yield is 59.98%.

[0048] Example 7

[0049] The light-cured powder was irradiated for 24 hours at a wavelength of 405 nm and a power of 35 W for photo-oxidation treatment.

[0050] The powder sample after photo-oxidation treatment was pyrolyzed in a slide rail tube furnace at a pyrolysis temperature of 600°C and a residence time of 30 min. The pyrolysis oil was collected by flushing the pipeline with dichloromethane, and the dichloromethane was evaporated using a rotary evaporator. The composition of the pyrolysis oil was obtained using GC-MS analysis software, and the aromatic yield was 11.6%.

[0051] Example 8

[0052] The light-cured powder was irradiated for 24 hours at a wavelength of 405 nm and a power of 35 W for photo-oxidation treatment.

[0053] Take the photocurable powder after photo-oxidation treatment and the catalyst (ZSM-5), mix them evenly in a ratio of 1:1, take the same mass of catalyst to cover the surface of the above mixture, and pyrolyze in a slide rail tube furnace, the pyrolysis temperature is 600℃, and the residence time is 30min. Use dichloromethane to flush the pipeline to collect the pyrolysis oil, and use a rotary evaporator to evaporate the dichloromethane. Use GC-MS analysis software to obtain the composition of the pyrolysis oil, of which the aromatic yield is 64.93%.

[0054] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for improving the quality of pyrolysis oil prepared by catalytic pyrolysis of photocured waste, characterized in that: The following steps are involved: Firstly, the photo-cured waste is subjected to photo-oxidation treatment, and then the photo-cured waste after the photo-oxidation treatment is subjected to catalytic pyrolysis; the photo-oxidation treatment specifically comprises irradiating the photo-cured waste with ultraviolet light under air conditions; The catalytic pyrolysis adopts a molecular sieve catalyst, and the molecular sieve catalyst is a ZSM-5 molecular sieve catalyst. During the catalytic pyrolysis, the photocured waste after photo-oxidation treatment and the catalyst are first mixed uniformly in a mass ratio of 1:1 to obtain a mixed sample, and then the catalyst of the same mass as the photocured waste after photo-oxidation pretreatment is taken to cover the surface of the mixed sample for catalytic pyrolysis. The method for improving the quality of pyrolysis oil prepared by catalytic pyrolysis of photocured waste is to increase the yield of aromatics in the pyrolysis oil; The wavelength of the ultraviolet light is 254-405nm; The irradiation power is 6-85W, and the irradiation time is 12h-288h; The photocured waste further comprises a step of grinding into 80 mesh powder before the photooxidation treatment; The temperature of the catalytic pyrolysis is 400° C.-700° C., and the time is 10-30 minutes.