Method for preparing high-oil-extended low-Mooney-viscosity reclaimed rubber from biomass oil

Abstract

The invention provides a method for preparing high-oil-extended low-Mooney-viscosity reclaimed rubber from biomass oil, and belongs to the field of rubber production and manufacturing. Industrial lignin and waste rubber powder are evenly mixed according to a certain proportion and then fed into a thermal cracking reactor for co-pyrolysis, biomass oil is prepared and obtained, the biomass oil and the waste rubber powder are mixed and then fed into a screw extruder for a decrosslinking reaction, then fed into the screw extruder and added into the screw extruder through a side feeding device for refining, and the biomass oil is obtained. Finally, the reclaimed rubber with high oil charge and low Mooney viscosity is prepared. In the production process, the energy consumption is low, and the additional value of resource utilization of the waste rubber and the industrial lignin is greatly improved.

Description

Technical Field

[0001] The invention relates to a regenerated rubber manufacturing technology, in particular to a method for preparing high-oil-filled low-Mooney viscosity regenerated rubber from biomass oil, belonging to the technical field of regenerated rubber production and manufacturing. Background Art

[0002] With the development of social economy, a large amount of waste rubber has been produced, which has brought great pressure to resources and the environment. How to recycle waste rubber efficiently and greenly is one of the great challenges facing polymer science and rubber industry. At present, the preparation and application of recycled rubber has become the main direction of recycling waste rubber in my country. Although the prepared recycled rubber has many advantages and has been widely used, the problems such as high energy consumption in the production process and rebound of Mooney viscosity of recycled rubber have not been completely solved.

[0003] The production process of reclaimed rubber is divided into two steps: desulfurization and refining. In the desulfurization stage, in order to achieve a better desulfurization effect, it is usually necessary to add a certain amount of rubber regenerator and swelling agent, which can not only improve the dispersion of desulfurization aids and increase the degree of desulfurization, but also give the reclaimed rubber good processing performance and mechanical properties. During the regeneration process, the swelling agent first penetrates into the cross-linked network of the vulcanized rubber, weakens the interaction between the rubber macromolecule chains and between the rubber macromolecule chains and the filler, expands the volume, and increases the distance between the rubber macromolecule chains, which is conducive to the diffusion of additives such as regeneration activators into the cross-linked network. The refining process greatly reduces the Mooney viscosity of the desulfurized rubber powder, significantly improves the processing performance, and basically remains unchanged in mechanical properties, but at the same time, the Mooney viscosity rebound problem is prominent. In addition, the rubber regenerator and swelling agent used in industrial production are used in large quantities and require high temperatures when used. In the rubber regeneration process, toxic gases such as hydrogen sulfide are easily produced, energy consumption is high, and secondary pollution to the environment is easily caused. Therefore, the development of efficient and environmentally friendly rubber regeneration additives is of great significance to the green and sustainable development of the rubber industry.

[0004] Lignin, one of the three main components of woody biomass, is composed of randomly bonded phenylpropane structural units. It has the outstanding characteristics of wide sources, huge reserves, and recyclable renewable, and has great application potential. However, in actual production, lignin is mainly discharged as waste or directly burned as fuel, resulting in serious waste of resources.

[0005] Therefore, finding ways to utilize lignin at a high value has become the focus of many research studies. Pyrolysis technology is a process that rapidly pyrolyzes biomass into liquid bio-oil, solid charcoal and non-condensable gases under medium temperature, short residence time and oxygen-free conditions. The bio-oil obtained by thermal cracking of lignin can be used as a swelling agent in the rubber regeneration process, while expanding the application range of lignin in rubber materials and improving its high-value utilization rate. Summary of the invention

[0006] The present invention provides a novel method for preparing highly oil-filled low Mooney viscosity reclaimed rubber by using biomass oil. The reclaimed rubber with low Mooney viscosity can be prepared by performing a decrosslinking reaction between biomass oil and waste rubber powder, so as to solve the technical problem of low application value of lignin in the field of reclaimed rubber preparation in the prior art.

[0007] The method for preparing high-oil-extended low-Mooney viscosity reclaimed rubber using biomass oil according to the embodiment of the present invention comprises the following steps:

[0008] The first step is to classify, sort, clean and dry the recycled waste rubber, and then put it into a crushing device to obtain 20-60 mesh waste rubber powder;

[0009] The second step is to dry, grind and crush the recovered industrial lignin to obtain lignin particles with a particle size of 0.2-0.5 mm;

[0010] In the third step, the waste rubber powder obtained in the first step and the lignin particles obtained in the second step are put into the first stirring and mixing device at a mass ratio of 10:3-6, and after being mixed evenly, they are transported to the thermal cracking reaction device at a reaction temperature of 420°C-500°C for co-pyrolysis reaction;

[0011] In the fourth step, the biomass pyrolysis gas with solid carbon residue obtained in the third step is sent to a cyclone separator, and after the carbon residue is separated, it enters a cooling device, is cooled for 2-5 minutes, and non-condensable gas is discharged to obtain biomass oil;

[0012] The fifth step is to put the waste rubber powder obtained in the first step and the biomass oil obtained in the fourth step into the second stirring and mixing device according to a mass ratio of 100:25-44, stir for 1-3 minutes, and then feed the discharged material into the first twin-screw extruder, control the temperature of the screw extruder to 180-260°C, and react for 2-5 minutes;

[0013] In the sixth step, the material obtained in the fifth step is fed into a second twin-screw extruder, and the biomass oil obtained in the fourth step is added through a side feeding device. After refining for 3-5 minutes, it is fed into a double-roll refiner to thinly pass through the sheet to prepare a reclaimed rubber with a Mooney viscosity of 20-45.

[0014] The method for preparing high-oil-filled low-Mooney viscosity reclaimed rubber from biomass oil as described above, wherein the moisture content of the waste rubber powder in the first step is less than 1%, and the waste rubber powder is any one or more combinations of waste tire tread rubber and full tire rubber.

[0015] The method for preparing high-oil-extended low-Mooney viscosity reclaimed rubber from biomass oil as described above, wherein the moisture content of industrial lignin in the second step is less than 2%, and the industrial lignin is any one or more combinations of alkali lignin, sulfate lignin, and lignin sulfonate.

[0016] The method for preparing high-oil-extended low-Mooney viscosity reclaimed rubber from biomass oil as described above, wherein the thermal cracking reaction device in the third step is any one of a fluidized bed reactor, a moving bed reactor, and a fixed bed reactor; and the residence time of the thermal cracking gas is 0.2s-0.5s.

[0017] The method for preparing high-oil-extended low-Mooney viscosity reclaimed rubber from biomass oil as described above, wherein the cooling medium of the cooling device in the fourth step is an oil substance, and the temperature is 120-150°C.

[0018] The method for preparing high-oil-filled low-Mooney viscosity reclaimed rubber from biomass oil as described above, wherein the first twin-screw extruder in the fifth step is a co-rotating twin-screw extruder, the aspect ratio of the screw is 28-36:1, the conveying section temperature of the screw extruder is 220-240°C, the shear section temperature is 240-260°C, and the cooling section temperature is 180-200°C.

[0019] The method for preparing high-oil-filled low-Mooney viscosity reclaimed rubber from biomass oil as described above, wherein the biomass oil added in the sixth step is 1 / 5 to 1 / 4 of the biomass oil in the fifth step, and the second twin-screw extruder is a counter-rotating twin-screw extruder, and the aspect ratio of the screw is 24-32:1.

[0020] The method for preparing high-oil-filled low-Mooney viscosity reclaimed rubber from biomass oil as described above, wherein in the sixth step, the roller spacing of the double-roll refiner is 0.3-0.5 mm, the roller speed is 25-35 r / min, the speed ratio is 1:1.25, and the roller temperature is 20-40°C.

[0021] The present invention mixes industrial lignin and waste rubber powder in a certain proportion and then sends them into a pyrolysis reactor for co-pyrolysis to prepare biomass oil. After the biomass oil and waste rubber powder are mixed, they first enter a screw extruder for de-crosslinking reaction, and then enter the screw extruder through a side feeding device to add the biomass oil for refining, and finally prepares reclaimed rubber with high oil filling and low Mooney viscosity. The energy consumption in the production process is low, and the added value of the resource utilization of waste rubber and industrial lignin is greatly increased. DETAILED DESCRIPTION

[0022] The method for preparing high-oil-extended low-Mooney viscosity reclaimed rubber from biomass oil of the present invention can be made of the following materials and components, but is not limited to the following materials and components, such as lignin, waste rubber, etc.

[0023] The method for preparing high-oil-extended low-Mooney viscosity reclaimed rubber using biomass oil in this embodiment comprises the following steps:

[0024] In the first step, the recycled waste rubber is classified, sorted, cleaned and dried, and then put into a crushing device to obtain 20-60 mesh waste rubber powder; the moisture content of the waste rubber powder in the first step is less than 1%, and the waste rubber powder is any one or more combinations of waste tire tread rubber and full tire rubber.

[0025] In the second step, the recovered industrial lignin is dried, ground and pulverized to obtain lignin particles with a particle size of 0.2-0.5 mm; in the second step, the moisture content of the industrial lignin is less than 2%, and the industrial lignin is any one or more combinations of alkali lignin, sulfate lignin, and lignin sulfonate.

[0026] In the third step, the waste rubber powder obtained in the first step and the lignin particles obtained in the second step are put into the first stirring and mixing device at a mass ratio of 10:3-6, and after being evenly mixed, they are transported to the thermal cracking reaction device at a reaction temperature of 420°C-500°C for co-pyrolysis reaction; the thermal cracking reaction device in the third step is any one of a fluidized bed reactor, a moving bed reactor, and a fixed bed reactor; and the residence time of the thermal cracking gas is 0.2s-0.5s.

[0027] In the fourth step, the biomass pyrolysis gas with solid carbon residue obtained in the third step is sent to a cyclone separator, and after the carbon residue is separated, it enters a cooling device, is cooled for 2-5 minutes, and non-condensable gases are discharged to obtain biomass oil; the cooling medium of the cooling device in the fourth step is an oil substance, and the temperature is 120-150°C.

[0028] In the fifth step, the waste rubber powder obtained in the first step and the biomass oil obtained in the fourth step are put into the second stirring and mixing device according to a mass ratio of 100:25-44, stirred for 1-3 minutes, and discharged into the first twin-screw extruder, the temperature of the screw extruder is controlled to be 180-260°C, and the reaction is carried out for 2-5 minutes; the first twin-screw extruder in the fifth step is a co-rotating twin-screw extruder, the aspect ratio of the screw is 28-36:1, the temperature of the conveying section of the screw extruder is 220-240°C, the temperature of the shearing section is 240-260°C, and the temperature of the cooling section is 180-200°C.

[0029] In the sixth step, the material obtained in the fifth step is fed into a second twin-screw extruder, and the biomass oil obtained in the fourth step is added through a side feeding device. After refining for 3-5 minutes, it is fed into a double-roll refiner to thinly pass through the sheet to prepare a reclaimed rubber with a Mooney viscosity of 20-45.

[0030] The biomass oil added in the sixth step is 1 / 5 to 1 / 4 of the biomass oil in the fifth step, the second twin-screw extruder is a counter-rotating twin-screw extruder, and the aspect ratio of the screw is 24-32: 1. The roller pitch of the twin-roll refiner in the sixth step is 0.3-0.5 mm, the roller speed is 25-35 r / min, the speed ratio is 1:1.25, and the roller temperature is 20-40°C.

[0031] The beneficial effects of the present invention are:

[0032] The uniformly mixed waste rubber powder and industrial wood are co-pyrolyzed in the pyrolysis reactor. Lignin is first pyrolyzed to produce active free radicals. Existing studies have shown that the thermal degradation of high molecular weight polymers is mainly a free radical-dominated mechanism. Therefore, the active free radicals released by the pyrolysis of lignin will effectively promote the de-crosslinking reaction of the waste rubber powder. The effective hydrogen-carbon ratio of the waste rubber powder is relatively high, and the hydrogen free radicals are released into the "free radical pool". Through the hydrogen transfer reaction, the bio-oil produced by the pyrolysis of lignin is promoted from oxygen-containing compounds to hydrocarbons. The presence of the catalyst can not only improve the pyrolysis efficiency of lignin, but also effectively reduce the production of coke during the pyrolysis process and promote the formation of aromatic compounds, thereby improving the quality of pyrolysis biomass oil.

[0033] The biomass oil obtained after pyrolysis and cooling has a high temperature and has a similar composition to aromatic hydrocarbon oil. It can be used as a swelling agent to participate in the desulfurization and regeneration process of waste rubber powder. In the desulfurization device, using the principle of similar compatibility, the waste rubber powder and the added biomass oil can be stirred and mixed to a uniform dispersion state in a short time. At the same time, the heat of the biomass oil itself can be effectively transferred to the waste rubber powder, and the preparation of reclaimed rubber can be achieved at a lower regeneration temperature, reducing the damage to the main chain of the rubber molecule. When entering the refining stage, according to existing research results, the main source of the Mooney viscosity rebound of reclaimed rubber is the active groups generated during the refining process. Therefore, we choose to add a certain mass fraction of biomass oil. On the one hand, it can effectively reduce the viscosity of the reclaimed rubber, making it easier to be refined, reducing production energy consumption and costs. On the other hand, it can adsorb active free radicals, reduce Mooney rebound, and improve the overall quality of reclaimed rubber. The prepared recycled rubber has high oil content and low Mooney viscosity, and little damage to the original additives in the waste rubber. When added to the rubber composition, it can replace more raw rubber, carbon black, operating oil, etc. The energy consumption in the production process is low, which greatly increases the added value of the resource utilization of waste rubber and industrial lignin.

[0034] Example 1

[0035] S1: The recycled waste rubber is classified, sorted, cleaned, dried, and put into a crushing device to obtain 24-mesh waste tire rubber powder;

[0036] S2: drying, grinding and crushing the recovered alkali lignin to obtain lignin particles with a particle size of 0.3 mm;

[0037] S3: the waste rubber powder obtained in S1 and the lignin particles obtained in S2 are put into the first stirring and mixing device at a mass ratio of 10:5, and after being mixed evenly, they are transported to the fluidized bed reactor at a reaction temperature of 463°C for co-pyrolysis reaction;

[0038] S4: sending the biomass pyrolysis gas with solid carbon residue obtained in S3 into a cyclone separator, separating the carbon residue and then entering a cooling device, the residence time of the pyrolysis gas is 0.3s, the temperature of the cooling oil is 130°C, cooling for 3min, discharging the non-condensable gas, and obtaining biomass oil;

[0039] S5: the waste rubber powder obtained in S1 and the biomass oil obtained in S4 are put into the second stirring and mixing device at a mass ratio of 100:28, stirred for 2 minutes, and discharged into the first co-rotating twin-screw extruder, the aspect ratio of the screw is 32:1, the conveying section temperature of the screw extruder is controlled to be 224°C, the shear section temperature is 251°C, the cooling section temperature is 182°C, and the reaction is carried out for 3 minutes;

[0040] S6: The material obtained in S5 is fed into a second counter-rotating twin-screw extruder with a screw length-diameter ratio of 28:1. The biomass oil obtained in S4 is added through a side feeding device, and the amount is 1 / 4 of the biomass oil in S5. After refining for 3 minutes, the material is fed into a twin-roll refiner and thinned out to obtain a reclaimed rubber with a Mooney viscosity of 36 and an oil filling amount of 35%.

[0041] Example 2

[0042] S1: The recycled waste rubber is classified, sorted, cleaned, dried, and put into a crushing device to obtain 32-mesh waste tire rubber powder;

[0043] S2: drying, grinding and crushing the recovered kraft lignin to obtain lignin particles with a particle size of 0.3 mm;

[0044] S3: the waste rubber powder obtained in S1 and the lignin particles obtained in S2 are put into the first stirring and mixing device at a mass ratio of 10:3, and after being mixed evenly, they are transported to the fluidized bed reactor at a reaction temperature of 471°C for co-pyrolysis reaction;

[0045] S4: sending the biomass pyrolysis gas with solid carbon residue obtained in S3 into a cyclone separator, separating the carbon residue and then entering a cooling device, the residence time of the pyrolysis gas is 0.3s, the temperature of the cooling oil is 138°C, cooling for 2min, discharging non-condensable gas, and obtaining biomass oil;

[0046] S5: the waste rubber powder obtained in S1 and the biomass oil obtained in S4 are put into the second stirring and mixing device at a mass ratio of 100:35, stirred for 2 minutes, and discharged into the first co-rotating twin-screw extruder, the aspect ratio of the screw is 36:1, the conveying section temperature of the screw extruder is controlled to be 227°C, the shear section temperature is 256°C, the cooling section temperature is 184°C, and the reaction is carried out for 3 minutes;

[0047] S6: The material obtained in S5 is fed into a second counter-rotating twin-screw extruder with a screw length-diameter ratio of 24:1. The biomass oil obtained in S4 is added through a side feeding device, and the amount is 1 / 5 of the biomass oil in S5. After refining for 3 minutes, the material is fed into a twin-roll refiner and thinned out to obtain a reclaimed rubber with a Mooney viscosity of 31 and an oil filling amount of 42%.

[0048] Example 3

[0049] S1: Classify, sort, clean and dry the recycled waste rubber, and put it into a crushing device to obtain 40 mesh waste tire tread rubber powder;

[0050] S2: drying, grinding and crushing the recovered alkali lignin to obtain lignin particles with a particle size of 0.4 mm;

[0051] S3: the waste rubber powder obtained in S1 and the lignin particles obtained in S2 are put into the first stirring and mixing device at a mass ratio of 10:6, and after being mixed evenly, they are transported to the moving bed reactor at a reaction temperature of 487°C for co-pyrolysis reaction;

[0052] S4: The biomass pyrolysis gas with solid carbon residue obtained in S3 is sent to a cyclone separator, and after the carbon residue is separated, it enters a cooling device. The residence time of the pyrolysis gas is 0.2s, the temperature of the cooling oil is 143°C, and it is cooled for 3min, and non-condensable gas is discharged to obtain biomass oil;

[0053] S5: the waste rubber powder obtained in S1 and the biomass oil obtained in S4 are put into the second stirring and mixing device at a mass ratio of 100:40, stirred for 2 minutes, and discharged into the first co-rotating twin-screw extruder, the aspect ratio of the screw is 36:1, the conveying section temperature of the screw extruder is controlled to be 227°C, the shear section temperature is 256°C, the cooling section temperature is 184°C, and the reaction is carried out for 3 minutes;

[0054] S6: The material obtained in S5 is fed into a second counter-rotating twin-screw extruder with a screw length-diameter ratio of 28:1. The biomass oil obtained in S4 is added through a side feeding device, and the amount is 1 / 5 of the biomass oil in S5. After refining for 3 minutes, the material is fed into a twin-roll refiner and thinned out to obtain a reclaimed rubber with a Mooney viscosity of 25 and an oil filling amount of 48%.

[0055] The serial numbers of the above embodiments of the present invention are for description only and do not represent the advantages and disadvantages of the embodiments. Through the description of the above implementation methods, those skilled in the art can clearly understand that the above embodiment methods can be implemented by means of some deformations plus the necessary general technology superposition; of course, they can also be implemented by simplifying some important technical features. Based on this understanding, the technical solution of the present invention is essentially or contributes to the prior art in the following aspects: the overall structure and connection method, and the structure described in each embodiment of the present invention.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing high-oil-extended low-Mooney viscosity reclaimed rubber from biomass oil, characterized in that: The following steps are involved: The first step is to classify, sort, clean and dry the recycled waste rubber, and then put it into a crushing device to obtain 20-60 mesh waste rubber powder; The second step is to dry, grind and crush the recovered industrial lignin to obtain lignin particles with a particle size of 0.2-0.5 mm; In the third step, the waste rubber powder obtained in the first step and the lignin particles obtained in the second step are put into the first stirring and mixing device at a mass ratio of 10:3-6, and after being mixed evenly, they are transported to the thermal cracking reaction device at a reaction temperature of 420°C-500°C for co-pyrolysis reaction; In the fourth step, the biomass pyrolysis gas with solid carbon residue obtained in the third step is sent to a cyclone separator, and after the carbon residue is separated, it enters a cooling device, is cooled for 2-5 minutes, and non-condensable gas is discharged to obtain biomass oil; The fifth step is to put the waste rubber powder obtained in the first step and the biomass oil obtained in the fourth step into the second stirring and mixing device according to a mass ratio of 100:25-44, stir for 1-3 minutes, and then feed the discharged material into the first twin-screw extruder, control the temperature of the screw extruder to 180-260°C, and react for 2-5 minutes; In the sixth step, the material obtained in the fifth step is fed into a second twin-screw extruder, and the biomass oil obtained in the fourth step is added through a side feeding device. After refining for 3-5 minutes, it is fed into a double-roll refiner to thinly pass through the sheet to prepare a reclaimed rubber with a Mooney viscosity of 20-45.

2. The method for preparing high oil-extended low Mooney viscosity reclaimed rubber from biomass oil according to claim 1, characterized in that: In the first step, the water content of the waste rubber powder is lower than 1%, and the waste rubber powder is any one or more combinations of waste tire tread rubber and full tire rubber.

3. The method for preparing high oil-extended low Mooney viscosity reclaimed rubber from biomass oil according to claim 1, characterized in that: In the second step, the moisture content of the industrial lignin is less than 2%, and the industrial lignin is any one or more combinations of alkali lignin, sulfate lignin, and lignin sulfonate.

4. The method for preparing high oil-extended low Mooney viscosity reclaimed rubber from biomass oil according to claim 1, characterized in that: The thermal cracking reaction device in the third step is any one of a fluidized bed reactor, a moving bed reactor, and a fixed bed reactor; and the residence time of the thermal cracking gas is 0.2s-0.5s.

5. The method for preparing high oil-extended low Mooney viscosity reclaimed rubber from biomass oil according to claim 1, characterized in that: The cooling medium of the cooling device in the fourth step is oily substances, and the temperature is 120-150°C.

6. The method for preparing high oil-extended low Mooney viscosity reclaimed rubber from biomass oil according to claim 1, characterized in that: In the fifth step, the first twin-screw extruder is a co-rotating twin-screw extruder, the aspect ratio of the screw is 28-36:1, the conveying section temperature of the screw extruder is 220-240°C, the shearing section temperature is 240-260°C, and the cooling section temperature is 180-200°C.

7. The method for preparing high oil-extended low Mooney viscosity reclaimed rubber from biomass oil according to claim 1, characterized in that: The biomass oil added in the sixth step is 1 / 5 to 1 / 4 of the biomass oil in the fifth step. The second twin-screw extruder is a counter-rotating twin-screw extruder, and the aspect ratio of the screw is 24-32:

1.

8. The method for preparing high oil-extended low Mooney viscosity reclaimed rubber from biomass oil according to claim 1, characterized in that: In the sixth step, the roller distance of the double-roll refiner is 0.3-0.5 mm, the roller speed is 25-35 r / min, the speed ratio is 1:1.25, and the roller temperature is 20-40°C.