Method for predicting acid-base properties of organic waste before gasification

Abstract

The present application relates to organic waste gasification technical field, especially to a kind of prediction method of acid-base before organic waste gasification.The prediction method provided by the present application includes: with organic waste as test object, with methanol as combustion improver, after oxygen bomb combustion is carried out under closed condition, cooling, to oxygen bomb combustion device is rinsed, the pH value of rinse solution is determined, and recorded as pH0;Methanol is carried out under closed condition after oxygen bomb combustion, cooling, to oxygen bomb combustion device is rinsed, the pH value of rinse solution is determined, and recorded as pH1;If pH0<pH1, the organic waste is acidic before gasification;If pH0>pH1, the organic waste is alkaline before gasification.The method fills the blank of the pH value judgment of quenching ash water in the process of organic waste gasification, and the operation method is simple, and the observation index is intuitive and reliable;And the method is fast, predictive and intuitive.

Description

Technical Field

[0001] This invention relates to the field of organic waste gasification technology, and in particular to a method for predicting the acidity or alkalinity of organic waste before gasification. Background Technology

[0002] Currently, industrial organic waste treatment technologies can be categorized into incineration, landfill, and resource utilization. Incineration primarily involves burning organic waste, with representative processes including cement kiln incineration and rotary kiln incineration. While incineration can achieve the harmless disposal of industrial organic hazardous waste, its resource utilization efficiency is low, indirectly leading to resource waste. Landfilling of organic waste results in significant waste of land resources, and the organic components in the waste pollute the soil. Resource utilization technology for organic waste is the main development direction for organic waste disposal today. Among these, high-temperature melting and gasification treatment technology for industrial waste offers relatively high resource utilization efficiency.

[0003] High-temperature melting and gasification technology for industrial organic waste utilizes high-temperature gasification and melting as the main reaction to fully utilize the organic components in the waste. This process converts organic matter into syngas (H2, CO2, CO), while inorganic matter is melted and water-quenched to form water-quenched slag. This achieves highly efficient utilization of organic matter, and the water quenching process also solidifies harmful components in the organic waste. However, this technology generates a large amount of quenching ash water during the rapid cooling and water quenching process. The pH value of this ash water significantly affects the stability of production conditions. Too high a pH will generate excessive scale that clogs pipes, while too low a pH will corrode them. Therefore, controlling the pH value of the water is a crucial issue that needs to be addressed in the process.

[0004] The current solution involves adjusting the pH of the ash water by directly adding acid / alkali to the quenched ash water. This method has a significant time lag, failing to predict and control the hazardous waste slurry before gasification, and thus represents a passive adjustment. Developing a method for detecting the pH of the ash water would significantly advance the process. Summary of the Invention

[0005] The purpose of this invention is to provide a method for predicting the acidity or alkalinity of organic waste before gasification. This method can clearly determine how to adjust the pH value of the quench ash water during the gasification process of organic waste.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for predicting the acidity or alkalinity of organic waste before gasification, comprising the following steps:

[0008] Organic waste was used as the test substance and methanol as the combustion accelerant. After the oxygen bomb was burned under closed conditions, it was cooled and the oxygen bomb combustion device was rinsed. The pH value of the rinsing solution was measured and recorded as pH0.

[0009] After methanol is burned in an oxygen bomb under closed conditions, it is cooled and the oxygen bomb combustion device is rinsed. The pH value of the rinsing solution is measured and recorded as pH1.

[0010] If pH0 < pH1, the organic waste is acidic before gasification; if pH0 > pH1, the organic waste is alkaline before gasification.

[0011] Preferably, the ratio of the test substance to the combustion accelerant is (0.3-0.5) g: 0.5 mL.

[0012] Preferably, the oxygen pressure during the combustion of the oxygen bomb is 1.5 to 3 MPa.

[0013] Preferably, the oxygen bomb combustion device includes an oxygen bomb pot;

[0014] Before the oxygen bomb combustion is carried out, the oxygen bomb pot is also cleaned.

[0015] Preferably, the cleaning agent used for the cleaning is an alkaline solution with a pH value of 11;

[0016] The solute in the alkaline solution is sodium carbonate and / or sodium hydroxide.

[0017] This invention provides a method for predicting the acidity or alkalinity of organic waste before gasification, comprising the following steps: using organic waste as the test substance and methanol as the combustion aid, performing oxygen bomb combustion under closed conditions, cooling, rinsing the oxygen bomb combustion device, and measuring the pH value of the rinsing liquid, denoted as pH0; performing oxygen bomb combustion with methanol under closed conditions, cooling, rinsing the oxygen bomb combustion device, and measuring the pH value of the rinsing liquid, denoted as pH1; if pH0 < pH1, the organic waste is acidic before gasification; if pH0 > pH1, the organic waste is alkaline before gasification. This method fills the gap in judging the pH value of quench ash water during the gasification process of organic waste. This operation method is simple, and the hazardous waste characteristics are directly converted into the pH value of the water body for measurement, making the observation indicators intuitive and reliable; moreover, this method is rapid, predictive, and intuitive. Detailed Implementation

[0018] This invention provides a method for predicting the acidity or alkalinity of organic waste before gasification, comprising the following steps:

[0019] Organic waste was used as the test substance and methanol as the combustion accelerant. After the oxygen bomb was burned under closed conditions, it was cooled and the oxygen bomb combustion device was rinsed. The pH value of the rinsing solution was measured and recorded as pH0.

[0020] After methanol is burned in an oxygen bomb under closed conditions, it is cooled and the oxygen bomb combustion device is rinsed. The pH value of the rinsing solution is measured and recorded as pH1.

[0021] If pH0 < pH1, the organic waste is acidic before gasification; if pH0 > pH1, the organic waste is alkaline before gasification.

[0022] In this invention, unless otherwise specified, all raw materials are commercially available products well known to those skilled in the art.

[0023] In this invention, the oxygen bomb combustion device includes an oxygen bomb pot;

[0024] Before the oxygen bomb combustion is carried out, the oxygen bomb pot is also cleaned.

[0025] Before the oxygen bomb combustion, the present invention preferably includes cleaning the oxygen bomb pot. In the present invention, the cleaning agent used for cleaning is preferably an alkaline solution, the pH value of which is preferably 11; the solute in the alkaline solution is preferably sodium carbonate and / or sodium hydroxide.

[0026] In this invention, the preferred cleaning process is to immerse the entire oxygen bomb cover platform in the alkaline solution for 10-60 seconds. After immersion, scrub with a test tube brush and rinse with clean water until no yellow dirt remains. Simultaneously, pour the alkaline solution into the oxygen bomb container and scrub with a test tube brush. After scrubbing, rinse with clean water and dry.

[0027] In this invention, the preferred ratio of the test substance to the combustion accelerant is (0.3–0.5) g: 0.5 mL, more preferably (0.35–0.45) g: 0.5 mL, and most preferably (0.38–0.42) g: 0.5 mL. In this invention, the oxygen pressure during the oxygen bomb combustion process is preferably 1.5–3 MPa, more preferably 1.8–2.6 MPa, and most preferably 2.0–2.3 MPa.

[0028] In this invention, the oxygen bomb combustion preferably includes sequential material filling and oxygen bomb combustion. The specific process is preferably as follows: The crucible filled with the test material is placed in the oxygen bomb cover rack and a combustion wire is installed. 10-20 mL of ultrapure water is added to the oxygen bomb barrel, and the oxygen bomb device is installed. The installed oxygen bomb device is then filled with oxygen. During the oxygen filling process, the oxygen filling pressure should be controlled at 1.5-3 MPa, and the oxygen purity ≥99%. After the oxygen is fully filled, the gas in the oxygen bomb is released. This filling and releasing process is repeated at least 5 times until the air inside the oxygen bomb device is replaced (if replacement is not performed, the oxygen and nitrogen in the oxygen bomb will form nitric acid during combustion, affecting the pH value of the subsequent washing liquid). After filling, the oxygen bomb device is placed in a calorimeter for combustion experiments. During the oxygen bomb combustion process, the organic halogens in the hazardous waste (organic waste) are converted into acidic gases, and the remaining substances are converted into ash.

[0029] The present invention does not impose any special limitations on the cooling process; any process well known to those skilled in the art can be used to cool the oxygen bomb device to room temperature.

[0030] After the cooling process is complete, the invention also includes releasing the remaining gas in the oxygen bomb.

[0031] In this invention, the rinsing solution used for rinsing is preferably ultrapure water.

[0032] The preferred method for determining the pH value of the eluent is to dilute the eluent to volume using a volumetric flask and then measure the pH value using a pH meter.

[0033] In this invention, the testing process and conditions for pH1 are preferably the same as those for pH0 described in the above technical solution.

[0034] In this invention, if pH0 < pH1, the organic waste is acidic before gasification; if pH0 > pH1, the organic waste is alkaline before gasification; when the organic waste is acidic before gasification, alkali is added during the gasification process; if it is necessary to determine the specific substance of the acidic substance, ion chromatography can be used to analyze the eluent; when the organic waste is alkaline before gasification, acid is added during the gasification process.

[0035] The following detailed description of the method for predicting the acidity and alkalinity of organic waste before gasification, provided by the present invention, is based on specific examples. However, these examples should not be construed as limiting the scope of protection of the present invention.

[0036] Example 1

[0037] Mix 10g of sodium hydroxide and 10g of sodium carbonate with 500mL of deionized water to obtain a mixed solution of sodium hydroxide and sodium carbonate.

[0038] Immerse the upper rack of the oxygen bomb in the mixture of sodium hydroxide and sodium carbonate for 10 seconds. Pour 10 mL of the mixture of sodium hydroxide and sodium carbonate into the oxygen bomb barrel to clean it. Then, thoroughly clean it with deionized water, dry it, and keep the oxygen bomb clean.

[0039] 0.3g of the organic waste to be tested (mainly composed of DMF, activated carbon and high molecular weight carbon chains) was placed in a combustion crucible, and methanol was used as a combustion aid. The amount of methanol combustion aid added was controlled at 0.5mL. 10mL of deionized water was added to the oxygen bomb barrel as an absorbent. After the oxygen bomb was filled with oxygen to a pressure of 2MPa, the gas in the oxygen bomb was released. The above filling and releasing process was repeated more than 5 times. After the combustion was completed, it was allowed to stand for more than 20 minutes until the oxygen bomb device cooled to room temperature. The remaining gas in the oxygen bomb was released, and the oxygen bomb cover platform, oxygen bomb barrel and crucible were rinsed with ultrapure water to obtain the rinsing solution.

[0040] The pH value of the eluent was determined by adjusting the volume of the eluent using a 100mL volumetric flask and then analyzed using a pH analyzer. The pH value of the eluent was 5.6.

[0041] pH value detection of blank samples:

[0042] Mix 10g of sodium hydroxide and 10g of sodium carbonate with 500mL of deionized water to obtain a mixed solution of sodium hydroxide and sodium carbonate.

[0043] Immerse the upper rack of the oxygen bomb in the mixture of sodium hydroxide and sodium carbonate for 10 seconds. Pour 10 mL of the mixture of sodium hydroxide and sodium carbonate into the oxygen bomb barrel to clean it. Then, thoroughly clean it with deionized water, dry it, and keep the oxygen bomb clean.

[0044] 0.5 mL of methanol was placed in the combustion crucible, and 10 mL of deionized water was added to the oxygen bomb barrel as an absorbent. After the oxygen bomb was filled with oxygen to a pressure of 2 MPa, the gas in the oxygen bomb was released. The above filling and releasing process was repeated more than 5 times. After the combustion was completed, the oxygen bomb device was allowed to stand for more than 20 minutes until it cooled to room temperature. The remaining gas in the oxygen bomb was released, and the oxygen bomb cover platform, oxygen bomb barrel and crucible were rinsed with ultrapure water to obtain the rinsing solution.

[0045] The pH value of the eluent was determined by adjusting the volume of the eluent using a 100mL volumetric flask and then analyzed using a pH analyzer. The pH value of the eluent was 5.7.

[0046] Therefore, the distillation residue can be directly vaporized without the need for additional acid or alkali.

[0047] Examples 2-4

[0048] pH value detection of blank samples is performed according to Example 1;

[0049] The samples to be tested were residue rich in dichloromethane (Example 2), activated carbon for absorbing hydrochloric acid tail gas (Example 3), and corn stalk fermentation residue (Example 4). The testing procedure was the same as in Example 1, and the test results are shown in Table 1.

[0050] Table 1 Test Results

[0051] pH 5.7 1.5 2.3 5.7

[0052] As shown in Table 1, the data results indicate that the residue rich in dichloromethane and the activated carbon that absorbs hydrochloric acid tail gas are acidic, while the fermentation residue is neutral.

[0053] Further ion chromatography analysis was performed on the residue rich in dichloromethane and the eluent from activated carbon used to absorb hydrochloric acid tail gas. The results are shown in Table 2.

[0054] Table 2. Ion chromatographic analysis results of dichloromethane-rich residue and eluent from activated carbon used to absorb hydrochloric acid tail gas.

[0055] residue 13.2 413.2 - 3.26 Activated carbon - 321.265 - 3.927

[0056] As shown in Table 2, the acidic substance in the residue rich in dichloromethane and the activated carbon that absorbs hydrochloric acid tail gas is hydrochloric acid. Hydrochloric acid will be generated during the combustion of dichloromethane, and the activated carbon adsorbent material also contains hydrochloric acid; that is, alkaline substances need to be added to the residue rich in dichloromethane and the activated carbon that absorbs hydrochloric acid tail gas.

[0057] Examples 5-6

[0058] pH value detection of blank samples is performed according to Example 1;

[0059] The samples to be tested were residue rich in dichloromethane + soda ash (the mass percentage of soda ash relative to the residue was 5%, and the type of soda ash was sodium hydroxide) (Example 5) and activated carbon + soda ash for absorbing hydrochloric acid tail gas (the mass percentage of soda ash relative to the residue was 3%, and the type of soda ash was sodium carbonate) (Example 6). The testing procedure was the same as in Example 1, and the test results are shown in Table 3.

[0060] Table 3 Test Results

[0061] pH 5.7 5.6 5.8

[0062] As shown in Table 3, the residue rich in dichloromethane + soda ash (the mass percentage of soda ash relative to the residue is 5%, and the type of soda ash is sodium hydroxide) described in Example 5 and the activated carbon + soda ash for absorbing hydrochloric acid tail gas described in Example 6 (the mass percentage of soda ash relative to the residue is 3%, and the type of soda ash is sodium carbonate) both meet the actual production requirements.

[0063] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for predicting the acidity or alkalinity of organic waste before gasification, characterized in that, Includes the following steps: Organic waste was used as the test substance and methanol as the combustion accelerant. After the oxygen bomb was burned under closed conditions, it was cooled and the oxygen bomb combustion device was rinsed. The pH value of the rinsing solution was measured and recorded as pH0. After methanol is burned in an oxygen bomb under closed conditions, it is cooled and the oxygen bomb combustion device is rinsed. The pH value of the rinsing solution is measured and recorded as pH1. If pH0 < pH1, the organic waste is acidic before gasification; if pH0 > pH1, the organic waste is alkaline before gasification.

2. The prediction method as described in claim 1, characterized in that, The ratio of the test substance to the combustion accelerant is (0.3-0.5) g: 0.5 mL.

3. The prediction method as described in claim 1, characterized in that, The oxygen pressure during the combustion of the oxygen bomb is 1.5 to 3 MPa.

4. The prediction method as described in claim 1, characterized in that, The oxygen bomb combustion device includes an oxygen bomb pot; Before the oxygen bomb combustion is carried out, the oxygen bomb pot is also cleaned.

5. The prediction method as described in claim 4, characterized in that, The cleaning agent used is an alkaline solution with a pH value of 11. The solute in the alkaline solution is sodium carbonate and / or sodium hydroxide.