A Classification and Modulation Method for Pyrolysis Oil of Organic Waste Suitable for Underground Sequestration

Abstract

The present invention belongs to the technical field related to carbon emission reduction and carbon sequestration, and discloses a classification modulation method for pyrolysis oil of organic waste suitable for underground sequestration. The method includes: S1 detecting and adjusting the moisture content in the organic waste to be treated to meet the preset moisture content; S2 classifying the organic waste to be treated into organic waste unsuitable for injection underground, organic waste suitable for direct injection underground, and organic waste suitable for co-injection with CO2 underground according to the unsaturation index; S3 the organic waste unsuitable for injection underground is not sequestered; for the organic waste suitable for direct injection underground, it is mixed with activated coke and then pressurized and injected underground for sequestration; for the organic waste suitable for co-injection with CO2 underground, it is mixed with CO2 and then injected underground under pressure for sequestration. Through the present invention, large-scale underground carbon sequestration is achieved, and at the same time, the synthesis reaction between the active components of pyrolysis oil of organic waste and CO2 is utilized to synergistically sequester CO2 underground, providing a new method for achieving the "dual carbon" goal.

Description

Technical Field

[0001] The present invention belongs to the technical field related to carbon emission reduction and carbon sequestration, and more specifically, relates to a method for classifying and modulating pyrolysis oil of organic waste suitable for underground sequestration. Background Art

[0002] At present, it is urgent to explore and develop new technical methods for large-scale treatment of organic waste and carbon dioxide to achieve the "dual carbon" goal.

[0003] The organic waste is pyrolyzed rapidly to generate pyrolysis oil of organic waste containing various active functional groups. The pyrolysis oil of organic waste has the advantages of easy transportation, high carbon content, high reactivity, strong fluidity, etc. Therefore, the pyrolysis oil of organic waste can undergo polymerization reactions under certain conditions to generate a large amount of carbon-containing solids. In particular, the unsaturated active functional groups (such as carbon-carbon double bonds, carbon-oxygen double bonds, aromatic rings, etc.) in the pyrolysis oil of organic waste can undergo various synthesis reactions (such as esterification reactions, carboxylation reactions, addition reactions, etc.) with carbon dioxide under the action of a catalyst, effectively increasing the carbon content in the pyrolysis oil of organic waste and efficiently fixing carbon dioxide. To achieve large-scale treatment of organic waste and carbon dioxide, the present invention provides a method for classifying and modulating pyrolysis oil of organic waste suitable for underground sequestration. Summary of the Invention

[0004] Aiming at the above defects or improvement requirements of the prior art, the present invention provides a method for classifying and modulating pyrolysis oil of organic waste suitable for underground sequestration, which solves the problem of sequestration of large-scale organic waste.

[0005] To achieve the above object, according to the present invention, there is provided a method for classifying and modulating pyrolysis oil of organic waste suitable for underground sequestration, the method comprising the following steps:

[0006] S1 Detect and adjust the moisture content in the organic waste to be treated so that its water content is greater than or equal to a preset moisture content;

[0007] S2 Detect the unsaturation index in the organic waste to be treated, and classify the organic waste to be treated into organic waste not suitable for injection underground, organic waste suitable for direct injection underground, and organic waste suitable for co-injection with CO2 underground according to the determination standard of the unsaturation index;

[0008] S3 For the organic waste not suitable for injection underground, it is not injected for underground sequestration; for the organic waste suitable for direct injection underground, it is mixed with activated coke and then injected underground under pressure for sequestration; for the organic waste suitable for co-injection with CO2 underground, it is mixed with CO2 and then injected underground under pressure for sequestration.

[0009] Further preferably, in step S2, the determination criteria for the unsaturation index are as follows:

[0010] When k < 0.1, it is an organic waste unsuitable for underground injection; when 0.1 ≤ k < 1.5, it is an organic waste suitable for direct underground injection; when k ≥ 2, it is an organic waste suitable for co-injection with CO2 underground, where k is the unsaturation index.

[0011] Further preferably, the unsaturation index is calculated according to the following relational expression:

[0012]

[0013] where C%, H%, and N% are the mass percentages of C, H, and N in the organic waste to be treated, respectively.

[0014] Further preferably, in step S3, for the organic waste suitable for direct underground injection, before mixing it with the activated coke, the pH value of the organic waste to be treated is first adjusted to meet a preset pH threshold.

[0015] Further preferably, the preset pH threshold is 5.

[0016] Further preferably, adjusting the pH value of the organic waste to be treated means adjusting a weak acid in the organic waste to be treated, and the weak acid is one or a mixture of formic acid and acetic acid.

[0017] Further preferably, the activated coke is a pyrolysis coke of organic waste with an oxygen content greater than 10% and a porosity greater than 30%, and the mass percentage range of the activated coke in the solution is 1% - 10%.

[0018] Further preferably, in step S3, for the organic waste suitable for co-injection with CO2 underground, a Lewis acid needs to be added to the organic waste to be treated before it is mixed with CO2.

[0019] Further preferably, the Lewis acid is one or a mixture of aluminum chloride and iron chloride, and the mass percentage range of the Lewis acid in the solution is 0.1% - 1%.

[0020] Further preferably, in a method for classifying and modulating pyrolysis oil of an organic waste suitable for underground storage, the gas concentration of CO2 is 1% - 100%.

[0021] Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention have the following beneficial effects:

[0022] 1. In the present invention, the unsaturation index is selected to classify the organic waste to be processed into different types, so as to distinguish whether it can be co-sequestered with CO2. The self-polymerization reaction of the pyrolysis oil of organic waste and the reaction of the pyrolysis oil of organic waste with CO2 are both a series of elementary reactions initiated by the unsaturated bonds in the pyrolysis oil of organic waste. Therefore, the higher the unsaturation of the pyrolysis oil of organic waste, that is, the stronger the reactivity of the pyrolysis oil of organic waste, the easier it is to occur chemical synthesis reactions. When the unsaturation index of the pyrolysis oil of organic waste is greater than 2, the pyrolysis oil of organic waste is rich in highly active unsaturated bonds, which can undergo a co-curing reaction with CO2, achieving the goal of sequestering the pyrolysis oil of organic waste underground while reducing carbon dioxide emissions. When the unsaturation index of the pyrolysis oil of organic waste is between 0.1 and 1.5, the reactivity of the pyrolysis oil of organic waste is weak, and it is difficult to achieve the goal of co-curing and sequestering with CO2, but it can undergo a self-polymerization and curing sequestration reaction under certain conditions. Therefore, the unsaturation index is selected as an index to map the reactivity of the pyrolysis oil of organic waste to distinguish its type;

[0023] 2. In the present invention, the organic waste with an unsaturation index greater than or equal to 2 is co-sequestered with CO2. The synthesis and curing reaction between the highly active pyrolysis oil of organic waste and carbon dioxide uses carbon dioxide as a C1 resource. On the one hand, it increases the carbon content of the sequestered species to achieve carbon fixation. On the other hand, it reduces the emission of CO2, realizing the large-scale treatment of organic waste and carbon dioxide, and further achieving the "dual carbon" goal of "carbon peak" and "carbon neutrality";

[0024] 3. The purpose of adjusting the pH value of the organic waste suitable for direct injection into the ground in the present invention is that it can react under acidic conditions by itself, and the addition of activated coke further promotes the reaction to form fixed carbon, that is, to achieve carbon sequestration;

[0025] 4. In the present invention, the moisture content in the organic waste is detected first. On the one hand, too low moisture content will block the pipeline. On the other hand, too low moisture content will result in too strong reactivity and cause the reaction to occur in the pipeline and block the pipeline. After adjusting the moisture content, the risk of pipeline blockage is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flowchart of a method for classifying and modulating the pyrolysis oil of organic waste suitable for underground sequestration constructed according to a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] As Figure 1 shown, a method for classifying and modulating pyrolysis oil of organic waste suitable for underground storage proposed by the present invention includes the following steps:

[0029] S1 Detect the moisture content of the pyrolysis oil of organic waste. If the moisture content is less than 50%, add water until it meets the standard. If the moisture content is greater than or equal to 50%, perform the next operation;

[0030] S2 Detect the unsaturation index k of the pyrolysis oil of organic waste. According to the unsaturation index k, the pyrolysis oil of organic waste is divided into pyrolysis oil of organic waste not suitable for injection underground, pyrolysis oil of organic waste suitable for direct injection underground, and pyrolysis oil of organic waste suitable for co-injection underground with CO2;

[0031] When the organic waste is pyrolysis oil of organic waste suitable for direct injection underground, detect the pH value of the pyrolysis oil of organic waste suitable for direct injection underground. If the pH value is greater than 5, add weak acid until the pH value is less than or equal to 5. If the pH value is less than or equal to 5, add a certain amount of activated coke to the pyrolysis oil of organic waste suitable for direct injection underground, and after sufficient mixing, directly pressurize and inject it underground through a pipeline;

[0032] When the organic waste is pyrolysis oil of organic waste suitable for co-injection underground with CO2, add a certain amount of Lewis acid to the pyrolysis oil of organic waste suitable for co-injection underground with CO2, and after sufficient mixing, co-pressurize and inject it underground with CO2.

[0033] Further, in step S1, preferably, the pyrolysis oil of organic waste is pyrolysis oil generated by rapid pyrolysis of organic waste such as biomass, solid waste, and medical waste.

[0034] Further, in step S2, the unsaturation index k detects the mass percentages of C, H, and N in the pyrolysis oil of organic waste by elemental analysis and is calculated by the following formula

[0035] Furthermore, in step S2, based on the fact that the greater the unsaturation index k, the stronger the reactivity of the pyrolysis oil of organic waste. When k < 0.1, the pyrolysis oil of organic waste mostly consists of saturated and stable substances with low reactivity and is not suitable for underground storage. When 0.1 ≤ k < 1.5, the pyrolysis oil of organic waste can undergo self-polymerization reaction under certain conditions and solidify under the underground conditions of high pressure and low temperature. When k ≥ 1.5, most of the pyrolysis oil of organic waste contains unsaturated active functional groups and is prone to undergo synthesis and solidification reaction with carbon dioxide under high pressure and low temperature conditions. Therefore, the pyrolysis oil of organic waste is classified into three categories according to the unsaturation index k. The unsaturation index k of the pyrolysis oil of organic waste suitable for injecting underground is < 0.1, the unsaturation index of the pyrolysis oil of organic waste suitable for directly injecting underground is 0.1 ≤ k < 1.5, and the unsaturation index k of the pyrolysis oil of organic waste suitable for co-injecting with CO2 underground is ≥ 1.5.

[0036] Furthermore, in step S3, the weak acid is formic acid, acetic acid, etc. Since the purpose of the present invention is to inject the pyrolysis oil of organic waste into underground storage, if a strong acidic substance is added to adjust the pH value too small, it will corrode the pipeline and cause adverse effects. However, it is necessary to ensure that the pyrolysis oil of organic waste is in a weakly acidic state to promote the self-polymerization reaction of the pyrolysis oil of organic waste under the underground conditions of high pressure and low temperature.

[0037] Furthermore, in step S4, the activated coke is the pyrolysis coke of organic waste with an oxygen content greater than 10% and a porosity greater than 30%. The products in the pyrolysis process of organic waste are flexibly applied to reduce the storage cost. At the same time, high oxygen content and high porosity are both beneficial to the underground solidification reaction of the pyrolysis oil of organic waste. The added mass percentage range of the activated coke is 1% - 10%. If the added amount of the activated coke is too small, the effect of catalyzing the self-polymerization reaction of the pyrolysis oil of organic waste under underground conditions is not obvious. If the added amount of the activated coke is too large, the fluidity of the pyrolysis oil of organic waste will be weakened and there is a risk of blocking the pipeline.

[0038] Furthermore, in step S5, a Lewis acid is added to catalyze the co-solidification reaction of the pyrolysis oil of organic waste with carbon dioxide under underground conditions. The preferred Lewis acids are aluminum chloride, ferric chloride, etc. The added mass percentage range of the Lewis acid is 0.1% - 1%. If the added amount of the Lewis acid is too small, the effect of catalyzing the co-solidification reaction of the pyrolysis oil of organic waste with carbon dioxide under underground conditions is not obvious. If the added amount of the Lewis acid is too large, the storage cost will be significantly increased and the pipeline will be corroded at the same time.

[0039] Furthermore, in steps S4 and S5, the mixing methods include ultrasonic, mechanical stirring, shearing, high-pressure shearing, etc., and the temperature during the mixing process shall not exceed 50°C. If the temperature during the mixing process is too high, the pyrolysis oil of organic waste will coke at high temperature, reducing the fluidity and there is a risk of blocking the pipeline.

[0040] Further, in step S5, the gas concentration of CO2 is 1% - 100%, which is widely applicable to carbon dioxide from various sources and reduces the cost of the carbon dioxide purification process.

[0041] Further, in steps S4 and S5, the underground includes gob areas formed after conventional coal mining, oil well gob areas, etc., which can reduce the drilling cost. At the same time, it solidifies the gob area to avoid collapse. The underground pressure shall not be lower than 7.38 Mpa, and the underground temperature shall not be lower than 50 °C, that is, the depth of underground storage shall not be too small to ensure that the conditions of underground storage are maintained at high pressure and low temperature, promoting the self-polymerization reaction of pyrolysis oil of organic waste and the co-solidification reaction between pyrolysis oil of organic waste and carbon dioxide, and at the same time preventing groundwater pollution.

[0042] The present invention will be further described below in conjunction with specific embodiments.

[0043] Example 1

[0044] (a) The straw pyrolysis oil obtained by rapid pyrolysis of straw at 500 °C was detected by a Karl Fischer moisture meter, and the moisture content in the straw pyrolysis oil was 73.6%;

[0045] (b) The straw pyrolysis oil was detected by elemental analysis, and the mass percentages of C, H, and N elements were obtained as 44.97%, 5.17%, and 0.11% respectively. The unsaturation index k = 1.31 was calculated by the formula, and the straw pyrolysis oil was classified as pyrolysis oil of organic waste suitable for direct injection into the underground;

[0046] (c) The pH value of the straw pyrolysis oil was detected by a pH meter and was 6, and formic acid was added until the pH was 5;

[0047] (d) Biomass char with an oxygen content of 13% and a porosity of 45% was added to the straw pyrolysis oil, and the mass percentage was 10%, and it was ultrasonically treated at a constant temperature of 30 °C for 30 min;

[0048] (e) Simulate the underground environment in a laboratory reactor, that is, inject the mixed straw pyrolysis oil under pressure into a closed reactor respectively, and then keep the pressure in the reactor at 8 MPa and the temperature at 50 °C;

[0049] (f) After reacting for 4 h, a coke-black solid was formed.

[0050] Example 2

[0051] (a) The plastic pyrolysis oil obtained by rapid pyrolysis of plastic at 500 °C was detected by a Karl Fischer moisture meter, and the moisture content in the plastic pyrolysis oil was 40.3%, and water was added until the moisture content was 51.8%;

[0052] (b) The plastic pyrolysis oil was detected by elemental analysis, and the mass percentages of C, H, and N elements were obtained as 64.88%, 4.37%, and 0.07% respectively. The unsaturation index k = 1.60 was calculated by the formula, and the plastic pyrolysis oil was classified as the pyrolysis oil of organic waste suitable for co-injection into the ground with CO2;

[0053] (c) Add 1% by mass of aluminum chloride to the plastic pyrolysis oil with qualified moisture content, and carry out constant-temperature mechanical stirring at 30 °C for 30 min;

[0054] (d) Simulate the underground environment in a laboratory reactor, that is, inject the mixed plastic pyrolysis oil and 100% carbon dioxide under pressure into the closed reactor respectively, and then keep the pressure in the reactor at 7.38 MPa and the temperature at 50 °C;

[0055] (e) After reacting for 6 h, both the liquid and gas formed dark black solids.

[0056] Example 3

[0057] (a) The medical waste pyrolysis oil obtained by rapid pyrolysis of medical waste at 500 °C was detected by a Karl Fischer moisture meter, and the moisture content in the straw pyrolysis oil was 55%;

[0058] (b) The medical waste pyrolysis oil was detected by elemental analysis, and the mass percentages of C, H, and N elements were obtained as 37.26%, 5.31%, and 2.17% respectively. The unsaturation index k = 1.17 was calculated by the formula, and the medical waste pyrolysis oil was classified as the pyrolysis oil of organic waste suitable for direct injection into the ground;

[0059] (c) The pH value of the medical waste pyrolysis oil was detected by a pH meter to be 6, and acetic acid was added until the pH was 5;

[0060] (d) Add biomass char with an oxygen content of 20% and a porosity of 40% to the medical waste pyrolysis oil, add 1% by mass, and carry out constant-temperature shearing at 30 °C for 30 min;

[0061] (e) Simulate the underground environment in a laboratory reactor, that is, inject the mixed medical waste pyrolysis oil under pressure into the closed reactor respectively, and then keep the pressure in the reactor at 7.38 MPa and the temperature at 50 °C;

[0062] (f) After reacting for 4 h, dark black solids were formed.

[0063] Example 4

[0064] (a) The plastic pyrolysis oil obtained by rapid pyrolysis of plastic at 500 °C was detected by a Karl Fischer moisture meter, and the moisture content in the plastic pyrolysis oil was 40.3%, and water was added until the moisture content was 51.8%;

[0065] (b) The pyrolysis oil of plastics was detected by elemental analysis, and the mass percentages of C, H, and N elements obtained were 64.88%, 4.37%, and 0.07% respectively. The unsaturation index k = 1.60 was calculated by the formula, and the pyrolysis oil of plastics was classified as the pyrolysis oil of organic waste suitable for co-injection into the ground with CO2;

[0066] (c) 0.1% by mass of ferric chloride was added to the pyrolysis oil of plastics with qualified moisture content, and mechanical stirring was carried out at a constant temperature of 30°C for 30 min;

[0067] (d) The underground environment was simulated in a laboratory reactor, that is, the mixed pyrolysis oil of plastics and 1% carbon dioxide were injected under pressure into a closed reactor respectively, and then the pressure in the reactor was maintained at 7.38 MPa and the temperature was 50°C;

[0068] After reacting for 6 h, both the liquid and the gas formed jet-black solids.

[0069] It is easy for those skilled in the art to understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A classification modulation method for pyrolysis oil of organic waste suitable for underground storage, characterized in that, The method includes the following steps: S1 Detect and adjust the moisture content in the organic waste to be treated so that its water content is greater than or equal to a preset moisture content; S2 Detect the unsaturation index in the organic waste to be treated, and classify the organic waste to be treated into organic waste unsuitable for underground injection, organic waste suitable for direct underground injection, and organic waste suitable for co-injection with CO2 underground according to the unsaturation index determination standard; S3 For the organic waste unsuitable for underground injection, do not inject it underground for storage; for the organic waste suitable for direct underground injection, mix it with activated coke and then inject it underground under pressure for storage; for the organic waste suitable for co-injection with CO2 underground, mix it with CO2 and then inject it underground under pressure for storage; In step S2, the unsaturation index determination standard is as follows: When k < 0.1, it is organic waste unsuitable for underground injection; when 0.1 ≤ k < 1.5, it is organic waste suitable for direct underground injection; when k ≥ 2, it is organic waste suitable for co-injection with CO2 underground, where k is the unsaturation index; The unsaturation index is calculated according to the following relational formula: k= Among them, , and are the mass percentages of C, H, and N in the organic waste to be treated, respectively.

2. The classification modulation method of pyrolysis oil from organic waste suitable for underground storage according to claim 1, characterized in that, In step S3, for the organic waste suitable for direct underground injection, before mixing it with the activated coke, first adjust the pH value of the organic waste to be treated so that it meets the preset pH threshold.

3. A method for classifying and modulating pyrolysis oil of organic waste suitable for underground storage according to claim 2, characterized in that, The preset pH threshold is 5.

4. A method for classifying and modulating pyrolysis oil of organic waste suitable for underground storage according to claim 2, characterized in that, Adjusting the pH value of the organic waste to be treated means adjusting a weak acid in the organic waste to be treated, and the weak acid is one or a mixture of formic acid and acetic acid.

5. A method for classifying and modulating pyrolysis oil of organic waste suitable for underground storage according to claim 1 or 2, characterized in that, In step S3, the activated coke is a pyrolysis coke of organic waste with an oxygen content greater than 10% and a porosity greater than 30%, and the mass percentage of the activated coke in the solution ranges from 1% to 10%.

6. A method for classifying and modulating pyrolysis oil of organic waste suitable for underground storage according to claim 1 or 2, characterized in that, In step S3, for the organic waste suitable for co-injection with CO2 underground, a Lewis acid needs to be added to the organic waste to be treated before it is mixed with CO2.

7. A method for classifying and modulating pyrolysis oil of organic waste suitable for underground storage according to claim 6, characterized in that, The Lewis acid is one or a mixture of aluminum chloride and ferric chloride, and the mass percentage of the Lewis acid in the solution ranges from 0.1% to 1%.

8. A method for classifying and modulating pyrolysis oil of organic waste suitable for underground storage according to claim 6, characterized in that, The gas concentration of the CO2 is 1% to 100%.

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