Method for preparing bio-oil through co-pyrolysis of waste oil and waste wood treated by chromized copper arsenate

Abstract

The invention discloses a method for preparing bio-oil through co-pyrolysis of waste oil and waste wood treated by chromized copper arsenate, and relates to the technical field of biomass thermal conversion, and the method comprises the following steps: crushing and screening the waste wood treated by chromized copper arsenate to obtain biomass powder; the method comprises the following steps: adding waste oil into biomass powder, uniformly mixing, carrying out rapid pyrolysis and heat preservation in an inert atmosphere, and obtaining a pyrolysis product after heat preservation is finished; and condensing and separating the pyrolysis product to obtain high-quality bio-oil and charcoal. In the co-pyrolysis process of the waste oil and the waste wood treated by the chromized copper arsenate, the waste oil and the waste wood treated by the chromized copper arsenate are jointly pyrolyzed into high-quality bio-oil, meanwhile, highly toxic polycyclic aromatic hydrocarbon in the bio-oil is controlled within a reasonable range, and residual heavy metals such as Cu, Cr and As in the waste wood treated by the chromized copper arsenate are fixed in the biochar, so that the waste wood treated by the chromized copper arsenate and the waste wood treated by the chromized copper arsenate are fully utilized. Meanwhile, the environmental risk level of the biochar is reduced to be clean.

Description

Technical Field

[0001] This invention relates to the field of biomass thermal conversion technology, and in particular to a method for preparing bio-oil by co-pyrolysis of waste oil and waste wood treated with chromated copper arsenate. Background Technology

[0002] Chromated copper arsenate (CCA) has long been used as a wood preservative or insecticide, widely applied to residential timber. Its main components are water-soluble salts of hexavalent chromium (38-45%), copper (23-25%), and pentavalent arsenic (30-37%). Hexavalent chromium and inorganic arsenic are highly toxic to humans, causing cell damage and even necrosis. It is reported that there are currently over 350 timber preservative production enterprises in my country, processing approximately 4.5 million cubic meters of outdoor preservative-treated wood annually. 3 The amount of wood treated annually by CCA preservatives accounts for more than 85%, and the amount of wood waste generated during the treatment process and the annual amount of wood waste are huge. If not handled properly, it will not only be a waste of resources, but will also have a serious impact on the environment and human health.

[0003] In the process of refining petroleum coke, the residue oil undergoes coking reaction in the coking tower, releasing a large amount of gaseous and liquid substances. After condensation, a large amount of waste oil is generated. Because its main component is polycyclic aromatic hydrocarbons, which are carcinogenic to the human body, it is listed as hazardous waste. However, its carbon-hydrogen ratio is high, making it an ideal hydrogen donor. Pyrolysis is a technology that decomposes organic compounds in biomass under anaerobic conditions to generate gas, biochar, and bio-oil. However, bio-oil obtained after biomass pyrolysis alone is difficult to use as fuel due to problems such as low calorific value, high oxygen content, high water content, and high acidity. In order to improve the quality of bio-oil, biomass is usually co-pyrolyzed with other high C / H organic matter, which will help improve carbon efficiency and bio-oil quality. Wang et al. co-pyrolyzed bamboo residue and waste lubricating oil to increase the yield of hydrocarbons in bio-oil [1]; Hammad et al. used rice stubble waste biomass and waste engine oil for co-pyrolysis to upgrade the obtained bio-oil, increasing the calorific value by 2.15 times and reducing the water content to 62.70% [2]. Therefore, there is an urgent need for a method to co-pyrolyze waste oil and waste wood treated with chromated copper arsenate to produce high-quality bio-oil, and to fix the heavy metals in it, thereby reducing the toxicity of bio-oil and the environmental risks of biochar. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing bio-oil by co-pyrolysis of waste oil and waste wood treated with copper arsenate chromate. Using waste wood treated with copper arsenate chromate and waste oil as raw materials, the high-quality bio-oil prepared has a yield of not less than 62.10%, a calorific value of not less than 38.42 MJ / kg, a water content of not more than 15.50%, a pH value of not more than 5.82, and the toxicity of polycyclic aromatic hydrocarbons in the bio-oil is reduced to 8.32 or below, and the environmental risk level of biochar is reduced to clean.

[0005] To achieve the above objectives, the present invention provides a method for preparing bio-oil by co-pyrolysis of waste oil and waste wood treated with copper arsenate chromate, comprising the following steps:

[0006] (1) The waste wood treated with copper arsenate chromate is crushed and sieved to obtain biomass powder;

[0007] (2) Add waste oil to biomass powder and mix evenly. Perform rapid pyrolysis under an inert atmosphere and keep warm. After the heat preservation is completed, obtain the reactants.

[0008] (3) High-quality bio-oil and biochar are obtained by condensing and separating the pyrolysis products.

[0009] Specifically, in the co-pyrolysis process of waste oil and waste wood treated with copper chromate arsenate, the waste oil and the waste wood treated with copper chromate arsenate are co-pyrolyzed into high-quality bio-oil. Simultaneously, the highly toxic polycyclic aromatic hydrocarbons (PAHs) in the bio-oil are controlled within a reasonable range, and the heavy metals such as Cu, Cr, and As remaining in the waste wood treated with copper chromate arsenate are fixed in the biochar. Using waste wood treated with copper chromate arsenate and waste oil as raw materials, the high-quality bio-oil produced has a yield of no less than 62.10%, a calorific value of no less than 38.42 MJ / kg, a water content of no more than 15.50%, and a pH value of no more than 5.82. The toxicity of PAHs in the bio-oil is reduced to 8.32 or below. This not only yields high-quality bio-oil but also reduces the environmental risk level of the biochar to clean.

[0010] Specifically, after pyrolysis, three-phase products are produced: solid, liquid, and gas. The gas phase consists of non-condensable components, the liquid phase consists of condensable components, and the solid phase consists of biochar. Bio-oil can be collected by condensing the condensable components using an ice-water mixture.

[0011] Furthermore, the sieving process described in step (1) involves passing through a 50-150 mesh sieve.

[0012] Furthermore, the waste oil mentioned in step (2) is one of waste engine oil, waste lubricating oil, or gutter oil.

[0013] Furthermore, the pyrolysis temperature in step (2) is 500–800 °C.

[0014] Specifically, the vertical tube furnace is heated to the target temperature, and a glass tube containing waste oil and biomass powder is placed in the heating zone after being purged with inert gas for rapid pyrolysis.

[0015] Furthermore, the waste oil mentioned in step (2) accounts for 20-80% of the mass of the biomass powder.

[0016] Furthermore, the heat preservation time mentioned in step (2) is 60 to 180 minutes.

[0017] Furthermore, the inert atmosphere mentioned in step (2) is nitrogen or argon, with a flow rate of 50-100 mL / min.

[0018] The beneficial effects of this invention are as follows:

[0019] (1) This invention utilizes the co-pyrolysis of waste oil and waste wood treated with copper arsenate chromate to prepare high-quality bio-oil, solving the problems of low calorific value, high water content, and high acidity of bio-oil obtained from rapid biomass pyrolysis. The high-quality bio-oil produced has a yield of no less than 62.10%, a calorific value of no less than 38.42 MJ / kg, a water content of no more than 15.50%, and a pH value of no more than 5.82, with the calorific value approaching that of diesel oil (42.7 MJ / kg). Furthermore, this invention is of great significance for the treatment of hazardous wastes such as waste wood and waste oil treated with copper arsenate chromate chromate, as well as for the production of high-quality bio-oil.

[0020] (2) The waste wood treated with copper arsenate chromate of the present invention is waste wood discarded in daily life. Through pyrolysis, heavy metals such as Cu, Cr and As in it are fixed in biochar. Compared with traditional degradation methods in the natural environment, it reduces its harm to the natural environment and human body.

[0021] (3) The waste oil used in this invention can also be waste engine oil, waste lubricating oil, etc. generated in the electrolytic aluminum industry. Traditional methods use chemical degradation or incineration to treat waste oil, which is costly and produces exhaust gas, polluting the environment. Pyrolyzing it into high-value bio-oil has extremely high economic value and realizes high-value reuse of waste.

[0022] (4) The potential toxicity of polycyclic aromatic hydrocarbons in the bio-oil prepared by this invention is reduced from 40.32 to 8.32, and the environmental risk level of biochar is reduced from high to clean, thus realizing the treatment of hazardous waste and reducing the harm to the environment. Attached Figure Description

[0023] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0024] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. In the description of the present invention, "a plurality of" means two or more, unless otherwise expressly specified.

[0025] The methods for assessing the toxicity of polycyclic aromatic hydrocarbons and the methods for assessing heavy metals (environmental risk assessment) are as follows in the following examples:

[0026] (1) The assessment method for highly toxic polycyclic aromatic hydrocarbons in bio-oils is one of the 16 priority control polycyclic aromatic hydrocarbon assessment methods specified by the U.S. Environmental Protection Agency:

[0027] The specific method for assessing polycyclic aromatic hydrocarbons (PAHs) is as follows: PAH toxicity = ∑PAH i ·TEF i

[0028] PAH i It is the concentration of the polycyclic aromatic hydrocarbon, TEF. i It is the toxic factor of this polycyclic aromatic hydrocarbon.

[0029] (2) The method for assessing heavy metals in biochar is to extract Cu, Cr and As from biochar using a sequential extraction method, and to calculate the potential environmental risk of heavy metals in biochar based on the toxicity factors of each metal.

[0030] The method for assessing heavy metals in biochar is to extract Cu, Cr, and As from biochar using a sequential extraction method, and calculate the potential environmental risk of heavy metals in biochar based on the toxicity factors of each metal.

[0031] C f =C m / C n

[0032] Er = T r ×C f

[0033] RI=∑Er

[0034] Where C f C is a pollutant containing heavy metals. m and C n These represent the unstable components (F1+F2+F3) and stable components (F4) of heavy metals, respectively; Er is the potential environmental risk index of heavy metals, with Tr values ​​of 2, 5 and 10 for Cr, Cu and As, respectively; RI is the total potential environmental risk index of heavy metals (divided into four levels: clean, moderate, need to be considered and high).

[0035] Example 1

[0036] A method for preparing high-quality bio-oil through co-pyrolysis of waste oil and waste wood treated with copper arsenate chromate includes the following steps: 4g of waste wood treated with copper arsenate chromate is crushed and passed through an 80-mesh sieve to obtain biomass powder. Waste engine oil is added to the biomass powder and mixed evenly, with the waste engine oil accounting for 60% of the mass of the waste wood treated with copper arsenate chromate chromate arsenate. Then, rapid pyrolysis is performed under an inert atmosphere (nitrogen as the carrier gas, flow rate 10mL / min) at 500℃ and held at that temperature for 120min. During this process, the waste engine oil and the waste wood treated with copper arsenate chromate chromate arsenate co-pyrolyze to produce high-quality bio-oil. Heavy metals such as Cu, Cr, and As remaining in the waste wood treated with copper arsenate chromate chromate arsenate are fixed in the biochar, thus obtaining the pyrolysis product. The pyrolysis product is then separated by condensation to obtain high-quality bio-oil, biochar, and gas.

[0037] The bio-oil and biochar collected in the above process were weighed and analyzed. The bio-oil yield, calorific value, water content, and pH value were 75.92%, 22.04 MJ / kg, 36.51%, and 2.86, respectively. The toxicity of polycyclic aromatic hydrocarbons in the bio-oil decreased from 40.32 to 4.67 (see Table 1). The biochar yield and calorific value were 11.38% and 28.12 MJ / kg, respectively, and the environmental risk was high (see Table 2).

[0038] Example 2

[0039] A method for preparing high-quality bio-oil through co-pyrolysis of waste engine oil and waste wood treated with copper arsenate chromate includes the following steps: 4g of waste wood treated with copper arsenate chromate is crushed and passed through an 80-mesh sieve to obtain biomass powder. Waste engine oil is added to the biomass powder and mixed evenly, with the waste engine oil accounting for 60% of the mass of the waste wood treated with copper arsenate chromate chromate arsenate. Then, rapid pyrolysis is performed under an inert atmosphere (nitrogen as the carrier gas, flow rate 10mL / min) at 600℃ and held at that temperature for 120min. During this process, the waste engine oil and the waste wood treated with copper arsenate chromate chromate arsenate co-pyrolyze to produce high-quality bio-oil. Heavy metals such as Cu, Cr, and As remaining in the waste wood treated with copper arsenate chromate chromate arsenate are fixed in the biochar, thus obtaining the pyrolysis product. The pyrolysis product is then separated by condensation to obtain high-quality bio-oil, biochar, and gas.

[0040] The bio-oil and biochar collected in the above process were weighed and analyzed. The bio-oil yield, calorific value, water content, and pH value were 68.51%, 28.53 MJ / kg, 34.23%, and 3.74, respectively. The toxicity of polycyclic aromatic hydrocarbons in the bio-oil was 13.88 (see Table 1). The biochar yield and calorific value were 10.83% and 29.25 MJ / kg, respectively. The environmental risk was high (see Table 2).

[0041] Example 3

[0042] A method for preparing high-quality bio-oil through co-pyrolysis of waste engine oil and waste wood treated with copper arsenate chromate includes the following steps: 4g of waste wood treated with copper arsenate chromate is crushed and passed through an 80-mesh sieve to obtain biomass powder. Waste engine oil is added to the biomass powder and mixed evenly, with the waste engine oil accounting for 60% of the mass of the waste wood treated with copper arsenate chromate chromate arsenate. Then, rapid pyrolysis is performed under an inert atmosphere (nitrogen as the carrier gas, flow rate 10mL / min) at 700℃ and held at that temperature for 120min. During this process, the waste engine oil and the waste wood treated with copper arsenate chromate chromate arsenate co-pyrolyze to produce high-quality bio-oil. Heavy metals such as Cu, Cr, and As remaining in the waste wood treated with copper arsenate chromate chromate arsenate are fixed in the biochar, thus obtaining the pyrolysis product. The pyrolysis product is then separated by condensation to obtain high-quality bio-oil, biochar, and gas.

[0043] The bio-oil and biochar collected in the above process were weighed and analyzed. The bio-oil yield, calorific value, water content, and pH value were 65.75%, 35.86 MJ / kg, 33.60%, and 4.91, respectively. The toxicity of polycyclic aromatic hydrocarbons in the bio-oil was 15.70 (see Table 1). The biochar yield and calorific value were 9.60% and 29.97 MJ / kg, respectively. The environmental risk was moderate (see Table 2).

[0044] Example 4

[0045] A method for preparing high-quality bio-oil through co-pyrolysis of waste engine oil and waste wood treated with copper arsenate chromate includes the following steps: 4g of waste wood treated with copper arsenate chromate is crushed and passed through an 80-mesh sieve to obtain biomass powder. Waste engine oil is added to the biomass powder and mixed evenly, with the waste engine oil accounting for 60% of the mass of the waste wood treated with copper arsenate chromate chromate arsenate. Then, rapid pyrolysis is performed under an inert atmosphere (nitrogen as the carrier gas, flow rate 10mL / min) at 800℃ and held at that temperature for 120min. During this process, the waste engine oil and the waste wood treated with copper arsenate chromate chromate arsenate co-pyrolyze to produce high-quality bio-oil. Heavy metals such as Cu, Cr, and As remaining in the waste wood treated with copper arsenate chromate chromate arsenate are fixed in the biochar, thus obtaining the pyrolysis product. The pyrolysis product is then separated by condensation to obtain high-quality bio-oil, biochar, and gas.

[0046] The bio-oil and biochar collected in the above process were weighed and analyzed. The bio-oil yield, calorific value, water content, and pH value were 62.10%, 38.42 MJ / kg, 28.51%, and 5.82, respectively. The toxicity of polycyclic aromatic hydrocarbons in the bio-oil was 8.32 (see Table 1). The biochar yield and calorific value were 9.00% and 31.49 MJ / kg, respectively. The environmental risk was clean (see Table 2).

[0047] Table 1. Data on bio-oil yield, calorific value, water content, pH value, and toxicity in Examples 1-4.

[0048]

[0049] Table 1. Yield, calorific value, and environmental risk data of biochar in Examples 1-4.

[0050]

[0051] Example 5 This example is a comparative example of Example 2.

[0052] The preparation method of bio-oil includes the following steps: 4g of waste wood treated with copper arsenate chromate is crushed and passed through an 80-mesh sieve to obtain biomass powder. Waste engine oil is added to the biomass powder and mixed evenly, wherein the waste oil accounts for 0% of the mass of the waste wood treated with copper arsenate chromate. Then, pyrolysis is performed under an inert atmosphere (nitrogen as the carrier gas, flow rate 10mL / min) at 600℃ for 120min. During this process, the waste wood treated with copper arsenate chromate chromate is pyrolyzed into high-quality bio-oil, and the residual heavy metals such as Cu, Cr, and As in the waste wood are fixed in the biochar, thus obtaining the pyrolysis product. The pyrolysis product is then separated by condensation to obtain high-quality bio-oil, biochar, and gas.

[0053] The bio-oil and biochar collected in the above process were weighed and analyzed. The bio-oil yield, calorific value, water content and pH value were 53.81%, 9.12 MJ / kg, 42.63% and 5.14, respectively, and the toxicity of polycyclic aromatic hydrocarbons in the bio-oil was 3.99.

[0054] It is evident that the bio-oil preparation method, due to the absence of waste oil, results in a low yield of bio-oil in the pyrolysis products. Furthermore, the calorific value, water content, pH value, and other parameters differ significantly from those obtained through co-pyrolysis, indicating lower quality.

[0055] Example 6 This example is a comparative example of Example 2.

[0056] A method for preparing high-quality bio-oil through co-pyrolysis of waste engine oil and waste wood treated with copper arsenate chromate includes the following steps: 4g of waste wood treated with copper arsenate chromate is crushed and passed through an 80-mesh sieve to obtain biomass powder. Waste engine oil is added to the biomass powder and mixed evenly, with the waste engine oil accounting for 80% of the mass of the waste wood treated with copper arsenate chromate chromate arsenate. Then, rapid pyrolysis is performed under an inert atmosphere (nitrogen as the carrier gas, flow rate 10mL / min) at 600℃ and held at that temperature for 120min. During this process, the waste engine oil and the waste wood treated with copper arsenate chromate chromate arsenate co-pyrolyze to produce high-quality bio-oil. Heavy metals such as Cu, Cr, and As remaining in the waste wood treated with copper arsenate chromate chromate arsenate are fixed in the biochar, thus obtaining the pyrolysis product. The pyrolysis product is then separated by condensation to obtain high-quality bio-oil, biochar, and gas.

[0057] The bio-oil and biochar collected in the above process were weighed and analyzed. The bio-oil yield, calorific value, water content, and pH value were 70.10%, 40.46 MJ / kg, 27.30%, and 5.97, respectively, and the toxicity of polycyclic aromatic hydrocarbons in the bio-oil was 12.59.

[0058] It is evident that although this preparation method involves the addition of a significant amount of waste oil, the quality of the bio-oil is not significantly improved, and the toxicity of polycyclic aromatic hydrocarbons in the bio-oil increases substantially.

[0059] Example 7 This example is a comparative example of Example 2.

[0060] The method for preparing high-quality bio-oil by co-pyrolysis of waste engine oil and waste wood treated with copper arsenate chromate includes the following steps: 4g of waste wood treated with copper arsenate chromate is crushed and passed through an 80-mesh sieve to obtain biomass powder. Waste engine oil is added to the biomass powder and mixed evenly, wherein the waste engine oil accounts for 60% of the mass of the waste wood treated with copper arsenate chromate. Then, rapid pyrolysis is performed under an inert atmosphere (nitrogen as the carrier gas, flow rate 10mL / min) at 800℃ and held at that temperature for 0min. During this process, the waste engine oil and the waste wood treated with copper arsenate chromate co-pyrolyze to produce high-quality bio-oil. Heavy metals such as Cu, Cr, and As remaining in the waste wood treated with copper arsenate chromate are fixed in the biochar, thus obtaining the pyrolysis product. The pyrolysis product is then separated by condensation to obtain high-quality bio-oil, biochar, and gas.

[0061] The biochar collected in the above process was weighed and analyzed. The biochar yield and calorific value were 12.34% and 27.84 MJ / kg, respectively, and the environmental risk was considered.

[0062] It is evident that this preparation method, due to the lack of heat preservation, results in a relatively low calorific value for biochar and a high level of environmental risk, thus warranting consideration.

[0063] Example 8

[0064] A method for preparing high-quality bio-oil through co-pyrolysis of waste engine oil and waste wood treated with copper arsenate chromate includes the following steps: 4g of waste wood treated with copper arsenate chromate is crushed and passed through an 80-mesh sieve to obtain biomass powder. Waste engine oil is added to the biomass powder and mixed evenly, with the waste engine oil accounting for 60% of the mass of the waste wood treated with copper arsenate chromate chromate arsenate. Then, rapid pyrolysis is performed under an inert atmosphere (nitrogen as the carrier gas, flow rate 10mL / min) at 800℃ and held at that temperature for 180min. During this process, the waste engine oil and the waste wood treated with copper arsenate chromate chromate arsenate co-pyrolyze to produce high-quality bio-oil. Heavy metals such as Cu, Cr, and As remaining in the waste wood treated with copper arsenate chromate chromate arsenate are fixed in the biochar, thus obtaining the pyrolysis product. The pyrolysis product is then separated by condensation to obtain high-quality bio-oil, biochar, and gas.

[0065] The biochar collected during the above process was weighed and analyzed. The biochar yield and calorific value were 8.67% and 32.44 MJ / kg, respectively, and the environmental risk was clean.

[0066] Example 9

[0067] A method for preparing high-quality bio-oil through co-pyrolysis of waste engine oil and waste wood treated with copper arsenate chromate includes the following steps: 4g of waste wood treated with copper arsenate chromate is crushed and passed through an 80-mesh sieve to obtain biomass powder. Waste engine oil is added to the biomass powder and mixed evenly, with the waste engine oil accounting for 60% of the mass of the waste wood treated with copper arsenate chromate chromate arsenate. Then, rapid pyrolysis is performed under an inert atmosphere (nitrogen as the carrier gas, flow rate 10mL / min) at 800℃ and held at that temperature for 120min. During this process, the waste engine oil and the waste wood treated with copper arsenate chromate chromate arsenate co-pyrolyze to produce high-quality bio-oil. Heavy metals such as Cu, Cr, and As remaining in the waste wood treated with copper arsenate chromate chromate arsenate are fixed in the biochar, thus obtaining the pyrolysis product. The pyrolysis product is then separated by condensation to obtain high-quality bio-oil, biochar, and gas.

[0068] The bio-oil and biochar collected in the above process were weighed and analyzed. The bio-oil yield, calorific value, water content, and pH value were 61.28%, 37.65 MJ / kg, 27.53%, and 5.62, respectively. The toxicity of polycyclic aromatic hydrocarbons in the bio-oil was 8.14. The biochar yield and calorific value were 9.09% and 32.23 MJ / kg, respectively. The environmental risk was clean.

[0069] Example 10

[0070] like Figure 1The method for preparing high-quality bio-oil by co-pyrolysis of waste lubricating oil and waste wood treated with copper arsenate chromate includes the following steps: 4g of waste wood treated with copper arsenate chromate is crushed and passed through a 50-mesh sieve to obtain biomass powder. Waste lubricating oil is added to the biomass powder and mixed evenly, wherein the waste lubricating oil accounts for 60% of the mass of the waste wood treated with copper arsenate chromate. Then, rapid pyrolysis is performed under an inert atmosphere (nitrogen as the carrier gas, flow rate 10mL / min) at 800℃ and held at that temperature for 120min. During this process, the waste lubricating oil and the waste wood treated with copper arsenate chromate co-pyrolyze to produce high-quality bio-oil. Heavy metals such as Cu, Cr, and As remaining in the waste wood treated with copper arsenate chromate are fixed in the biochar, thus obtaining the pyrolysis product. The pyrolysis product is then separated by condensation to obtain high-quality bio-oil, biochar, and gas.

[0071] The bio-oil and biochar collected in the above process were weighed and analyzed. The bio-oil yield, calorific value, water content, and pH value were 60.87%, 37.67 MJ / kg, 14.32%, and 5.91, respectively. The toxicity of polycyclic aromatic hydrocarbons in the bio-oil was 7.98. The biochar yield and calorific value were 9.17% and 31.42 MJ / kg, respectively. The environmental risk was clean.

[0072] Example 11

[0073] like Figure 1 The method for preparing high-quality bio-oil by co-pyrolysis of waste cooking oil and waste wood treated with copper arsenate chromate includes the following steps: 4g of waste wood treated with copper arsenate chromate is crushed and passed through an 80-mesh sieve to obtain biomass powder. Waste oil is added to the biomass powder and mixed evenly, wherein the waste oil accounts for 60% of the mass of the waste wood treated with copper arsenate chromate. Then, rapid pyrolysis is performed under an inert atmosphere (argon as the carrier gas, flow rate 50mL / min) at 800℃ and held at that temperature for 120min. During this process, the waste cooking oil and the waste wood treated with copper arsenate chromate co-pyrolyze into high-quality bio-oil. Heavy metals such as Cu, Cr, and As remaining in the waste wood treated with copper arsenate chromate are fixed in the biochar, thus obtaining the pyrolysis product. The pyrolysis product is then separated by condensation to obtain high-quality bio-oil, biochar, and gas.

[0074] The bio-oil and biochar collected in the above process were weighed and analyzed. The bio-oil yield, calorific value, water content, and pH value were 60.14%, 37.27 MJ / kg, 14.29%, and 5.98, respectively. The toxicity of polycyclic aromatic hydrocarbons in the bio-oil was 8.35. The biochar yield and calorific value were 9.10% and 31.87 MJ / kg, respectively. The environmental risk was clean.

[0075] Example 12

[0076] like Figure 1 The method for preparing high-quality bio-oil by co-pyrolysis of waste cooking oil and waste wood treated with copper arsenate chromate includes the following steps: 4g of waste wood treated with copper arsenate chromate is crushed and passed through a 150-mesh sieve to obtain biomass powder. Waste oil is added to the biomass powder and mixed evenly, wherein the waste cooking oil accounts for 60% of the mass of the waste wood treated with copper arsenate chromate. Then, rapid pyrolysis is performed under an inert atmosphere (nitrogen as the carrier gas, flow rate 10mL / min) at 800℃ and held at that temperature for 120min. During this process, the waste cooking oil and the waste wood treated with copper arsenate chromate co-pyrolyze to produce high-quality bio-oil. Heavy metals such as Cu, Cr, and As remaining in the waste wood treated with copper arsenate chromate are fixed in the biochar, thus obtaining the pyrolysis product. The pyrolysis product is then separated by condensation to obtain high-quality bio-oil, biochar, and gas.

[0077] The bio-oil and biochar collected in the above process were weighed and analyzed. The bio-oil yield, calorific value, water content, and pH value were 62.45%, 38.04 MJ / kg, 15.43%, and 6.13, respectively. The toxicity of polycyclic aromatic hydrocarbons in the bio-oil was 8.24. The biochar yield and calorific value were 8.77% and 30.62 MJ / kg, respectively. The environmental risk was clean.

[0078] In summary, when the waste oil accounts for 0-80% of the biomass powder mass, the pyrolysis temperature is 500-800℃, and the holding time is 60-180 min, the optimal values ​​are 60% waste oil, 800℃, and 120 min. These parameters significantly impact the quality of the bio-oil; both high and low values ​​will affect its quality. The high-quality bio-oil prepared by this invention has a yield of not less than 62.10%, a calorific value of not less than 38.42 MJ / kg, a water content of not more than 15.50%, and a pH value of not more than 5.82. The toxicity of polycyclic aromatic hydrocarbons in the bio-oil is reduced from 40.32 to 8.32 or below, and the environmental risk level of the biochar is reduced from high to clean.

[0079] The above-disclosed embodiments are merely some examples of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that implementing all or part of the above embodiments and making equivalent changes in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A method for preparing bio-oil by co-pyrolysis of waste oil and waste wood treated with chromated copper arsenate, characterized in that: The steps include: Crushing and screening the waste wood treated with chromated copper arsenate to obtain biomass powder; Add waste oil to biomass powder and mix them evenly, perform rapid pyrolysis and keep warm under an inert atmosphere, and obtain pyrolysis products after the insulation is completed; The pyrolysis products are condensed and separated to obtain high-quality bio-oil and biochar.

2. The method for preparing bio-oil by co-pyrolysis of waste oil and waste wood treated with chromated copper arsenate according to claim 1, characterized in that: The sieving in step (1) is performed through a 50-150 mesh sieve.

3. The method for preparing bio-oil by co-pyrolysis of waste oil and waste wood treated with chromated copper arsenate according to claim 1, characterized in that: The waste oil in step (2) is one of waste engine oil, waste lubricating oil or waste cooking oil.

4. The method for preparing bio-oil by co-pyrolysis of waste oil and waste wood treated with chromated copper arsenate according to claim 1, characterized in that: The pyrolysis temperature in step (2) is 500-800°C.

5. The method for preparing bio-oil by co-pyrolysis of waste oil and waste wood treated with chromated copper arsenate according to claim 1, characterized in that: The waste oil in step (2) accounts for 20-80% of the mass of the biomass powder.

6. The method for preparing bio-oil by co-pyrolysis of waste oil and waste wood treated with chromated copper arsenate according to claim 1, characterized in that: The holding time in step (2) is 60 to 180 min.

7. The method for preparing bio-oil by co-pyrolysis of waste oil and waste wood treated with chromated copper arsenate according to claim 1, characterized in that: The inert atmosphere described in step (2) is nitrogen or argon with a flow rate of 50-100 mL / min.

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