Method for analyzing organic chlorine and inorganic chlorine in coal
By combining low-temperature plasma ashing with microcoulometric analysis, the accurate detection of organic and inorganic chlorine in coal has been achieved, solving the problem of distinguishing between organic and inorganic chlorine in existing technologies and providing a simple and efficient detection method.
Patent Information
- Application Number
- CN202511668202.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-14
- Publication Date
- 2025-12-23
AI Technical Summary
Existing technologies cannot effectively distinguish and detect the occurrence forms of organic and inorganic chlorine in coal, and cannot meet the precise detection requirements for clean coal utilization.
Low-temperature plasma ashing technology was used to remove organic chlorine from coal, and the total chlorine and inorganic chlorine content was detected by microcoulometric analysis. The organic chlorine content was calculated by the difference method. The specific parameters were: temperature 50~60℃, oxygen pressure 0.2mbar, radio frequency power 50-100W, and ashing time 168 hours.
It achieves non-destructive separation of organic and inorganic chlorine in coal, is simple, highly sensitive, has low operating requirements, and is suitable for batch operations.
Smart Images
Figure CN121186286A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of coal quality analysis, and particularly relates to a method for analyzing organic chlorine and inorganic chlorine in coal. BACKGROUND
[0002] As the core process of coal grading utilization, the thermo-chemical conversion of coal can realize the efficient conversion of raw coal into high-heat-value gas, liquid tar and solid semi-coke and other high-value-added products, and has key significance in promoting the green and efficient development and utilization of coal resources. In the process of coal pyrolysis conversion, the organic chlorine compounds (such as chlorinated aromatic hydrocarbons, chlorinated phenols, etc.) in the tar component not only cause equipment corrosion and pipeline blockage problems, but also poison the catalyst in the later chemical conversion stage, thereby affecting the service life of the catalyst and the stable operation of the system, becoming a key technical bottleneck restricting the clean and efficient utilization of coal. The chlorine elements in coal can significantly change the quality characteristics of the pyrolysis products. In the pyrolysis reaction process, chlorine elements undergo a migration and conversion process, not only generating HCl, Cl2 and other toxic and harmful gases, which pollute the ecological environment, but also reducing product quality indicators and accelerating the corrosion degree of the reaction equipment, and the equipment corrosion degree and the chlorine content in the coal show a significant positive correlation.
[0003] Although the current detection technology system of chlorine elements in coal shows a diversified development trend, various methods have significant technical limitations. For example, the molar method and mercury nitrate titration method in chemical analysis, the end point of nitric acid titration method is easier to judge, so it is widely used, but it has high requirements for the titration environment. In addition, there are instrumental analysis methods, including emission spectroscopy, neutron activation method, scanning electron microscopy and X-ray diffraction method. These methods are relatively simple and fast to operate and can be operated in batches, but the results are not accurate enough. For electrochemical methods, there are potential titration and ion selective electrode methods. These two methods have higher accuracy than chemical methods and lower experience requirements for detection personnel, but the results are easily affected by temperature and have high requirements for the detection environment. Finally, there are national standard methods, including the Eschka mixed agent melting sample-potassium thiocyanate titration method and high-temperature combustion hydrolysis potential titration method. These two methods are simple to operate and have relatively reliable results, but they are difficult to operate in batches. Although the existing detection technology can measure the total chlorine content, it cannot distinguish the occurrence form of organic chlorine and inorganic chlorine, and cannot meet the urgent need for accurate detection of clean coal utilization. Therefore, it is urgent to realize the differential detection of organic chlorine and inorganic chlorine. SUMMARY
[0004] The purpose of this invention is to provide an analytical method for organic and inorganic chlorine in coal. Organic chlorine in coal is removed by low-temperature plasma ashing, and the decomposition of inorganic chlorides is inhibited. Then, microcoulometric analysis is used to detect the total chlorine content and the inorganic chlorine content in the coal after low-temperature plasma ashing. The organic chlorine content in the coal is calculated by subtraction. While existing technologies also involve the use of low-temperature plasma ashing to remove organic matter from coal, there is no record of low-temperature plasma ashing completely removing organic chlorine from coal. This invention is the first to accurately determine the content of organic and inorganic chlorine in coal using low-temperature plasma ashing combined with microcoulometric analysis. This method is simple, novel, and has low operational requirements.
[0005] To achieve the above objectives, the present invention provides the following technical solution:
[0006] One of the technical solutions of this invention is to provide an analytical method for organic and inorganic chlorine in coal, comprising the following steps:
[0007] The total chlorine content in coal was determined using microcoulometric analysis.
[0008] Organic chlorine in coal is removed by low-temperature plasma ashing to obtain residue; the chlorine content in the residue is determined by microcoulometric analysis, which is the inorganic chlorine content in the coal.
[0009] The content of organic chlorine in coal = the content of total chlorine in coal - the content of inorganic chlorine in coal;
[0010] The parameters for the low-temperature plasma ashing are set as follows: temperature 50~60℃, oxygen pressure not exceeding 0.2mbar, radio frequency power 50~100W, and ashing time 72~168h.
[0011] A schematic diagram of the analytical method for organic and inorganic chlorine in coal of this invention is shown below. Figure 1 .
[0012] Preferably, the combustion temperature in the microcoulometric analysis is 900~1000℃.
[0013] Preferably, the titratable chloride ions generated by the microcoulometric analysis are dissolved in a 12.2 mol / L acetic acid solution.
[0014] Preferably, the low-temperature plasma ashing is achieved using a low-temperature ashing apparatus; the microcoulombic analysis is achieved using a microcoulombic analyzer.
[0015] The analytical method of this invention, implemented by using two instruments in combination, can minimize human error.
[0016] The beneficial technical effects of the present invention are as follows:
[0017] This invention removes organic chlorine from coal and inhibits the decomposition of inorganic chlorides by low-temperature plasma ashing. Then, the total chlorine content in the coal and the inorganic chlorine content in the coal after low-temperature plasma ashing are detected by microcoulometric analysis. The organic chlorine content in the coal is calculated by the difference method.
[0018] The analytical method provided by this invention achieves the non-destructive separation of organic and inorganic chlorine in coal for the first time. Moreover, the method is simple, novel, has low operating requirements, and high sensitivity, and has good prospects for widespread application. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0020] Figure 1 This is a schematic diagram of the analytical method for organic and inorganic chlorine in coal according to the present invention. Detailed Implementation
[0021] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.
[0022] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.
[0023] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0024] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.
[0025] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.
[0026] The raw coal used in Examples 1-4 of this invention is pulverized powder with a mesh size greater than 180 mesh.
[0027] Example 1
[0028] 0.976 g of coking coal was taken and placed in a low-temperature ashing apparatus. The ashing apparatus temperature was set to 60℃, the oxygen pressure to 0.2 mbar, and the radio frequency power to 50 W. Low-temperature plasma ashing was performed for 168 hours until constant weight (0.087 g of ashed weight). The residue obtained from low-temperature plasma ashing was placed in the quartz tube of a microcoulometric analyzer. The temperature was set to 1000℃, and high-purity oxygen (99.9%) was introduced. After high-temperature pyrolysis, the residue was transferred to the electrolytic cell of the microcoulometric analyzer. The generated chloride ions were dissolved using a 12.2 mol / L acetic acid solution. After titration, the inorganic chloride content in the raw coal was found to be 189.77 mg / kg.
[0029] The total chlorine content in the raw coal without low-temperature plasma ashing was then determined by the same microcoulometric analysis method, and the result was 576.48 mg / kg. Subtracting this from the total chlorine content, the organic chlorine content in the raw coal was found to be 386.71 mg / kg.
[0030] Example 2
[0031] 0.937 g of weakly caking coal was taken and placed in a low-temperature ashing apparatus. The ashing apparatus temperature was set to 60℃, the oxygen pressure to 0.2 mbar, and the radio frequency power to 50 W. Low-temperature plasma ashing was performed for 168 hours until constant weight (0.097 g of ashed coal). The residue obtained from low-temperature plasma ashing was placed in the quartz tube of a microcoulometric analyzer. The temperature was set to 1000℃, and high-purity oxygen (99.9%) was introduced. After high-temperature pyrolysis, the residue was transferred to the electrolytic cell of the microcoulometric analyzer. The chloride ions generated were dissolved using a 12.2 mol / L acetic acid solution. After titration, the inorganic chloride content in the raw coal was found to be 212.89 mg / kg.
[0032] The total chlorine content in the raw coal without low-temperature plasma ashing was then determined by the same microcoulometric analysis method, and the result was 646.5 mg / kg. Subtracting this from the total chlorine content, the organic chlorine content in the raw coal was found to be 433.61 mg / kg.
[0033] Example 3
[0034] 1.032 g of coking coal was taken and placed in a low-temperature ashing apparatus. The ashing apparatus temperature was set to 60℃, the oxygen pressure to 0.2 mbar, and the radio frequency power to 50 W. Low-temperature plasma ashing was performed for 168 hours until constant weight (0.1605 g of ashed weight). The residue obtained from low-temperature plasma ashing was placed in the quartz tube of a microcoulomb analyzer. The temperature was set to 1000℃, and high-purity oxygen (99.9%) was introduced. After high-temperature pyrolysis, the residue was transferred to the electrolytic cell of the microcoulomb analyzer. The generated chloride ions were dissolved using a 12.2 mol / L acetic acid solution. After titration, the inorganic chloride content in the raw coal was found to be 480.08 mg / kg.
[0035] The total chlorine content in the raw coal without low-temperature plasma ashing was then determined by the same microcoulometric analysis method, and the result was 734.01 mg / kg. Subtracting this from the total chlorine content, the organic chlorine content in the raw coal was found to be 253.93 mg / kg.
[0036] Example 4
[0037] 0.41g of lean coal was taken and placed in a low-temperature ashing apparatus. The ashing apparatus temperature was set to 60℃, the oxygen pressure to 0.2mbar, and the radio frequency power to 50W. Low-temperature plasma ashing was performed for 168 hours until constant weight (0.045g of ashed weight). The residue obtained from low-temperature plasma ashing was placed in the quartz tube of a microcoulometric analyzer. The temperature was set to 1000℃, and high-purity oxygen (99.9%) was introduced. After high-temperature pyrolysis, the residue was transferred to the electrolytic cell of the microcoulometric analyzer. The generated chloride ions were dissolved using a 12.2mol / L acetic acid solution. After titration, the inorganic chloride content in the raw coal was found to be 272.55mg / kg.
[0038] The total chlorine content in the raw coal without low-temperature plasma ashing was then determined by the same microcoulometric analysis method, and the result was 541.52 mg / kg. Subtracting this from the total chlorine content, the organic chlorine content in the raw coal was found to be 268.97 mg / kg.
[0039] Experiments to verify the accuracy of the analytical method in this invention:
[0040] Example 5
[0041] Sodium chloride and calcium chloride were used as inorganic chlorine model compounds, and biphenyl-4-formyl chloride and thiobis(dichlorophenol) were used as organic chlorine model compounds. They were mixed in a mass ratio of 1:1:1:1. The theoretical content of inorganic chlorine in the sample was 311,325 mg / kg, and the theoretical content of organic chlorine was 140,450 mg / kg. The theoretical content of organic chlorine accounted for approximately 31.09% of the total chlorine, and the theoretical content of inorganic chlorine accounted for approximately 68.91% of the total chlorine.
[0042] The sample was placed in a low-temperature ashing apparatus with the temperature set at 60℃, oxygen pressure at 0.2 mbar, and radio frequency power at 50 W. Low-temperature plasma ashing was performed for 168 hours until constant weight. The residue obtained from low-temperature plasma ashing was placed in the quartz tube of a microcoulometric analyzer, with the temperature set at 1000℃ and 99.9% pure oxygen introduced. After high-temperature pyrolysis, the residue was transferred to the electrolytic cell of the microcoulometric analyzer. The generated chloride ions were dissolved using a 12.2 mol / L acetic acid solution. After titration, the inorganic chlorine content in the mixed model compound was found to be 311010 mg / kg. Based on the total chlorine content of 451775 mg / kg, the organic chlorine content was found to be 140765 mg / kg. The organic chlorine content accounted for approximately 31.16% of the total chlorine, and the inorganic chlorine content accounted for 68.84%. The actual measured results of this method are basically consistent with the theoretical values.
[0043] Example 6
[0044] Sodium chloride and calcium chloride were used as inorganic chlorine model compounds, and biphenyl-4-formyl chloride and thiobis(dichlorophenol) were used as organic chlorine model compounds. They were mixed in a mass ratio of 1:2:1:1. At this time, the theoretical content of inorganic chlorine in the sample was 376,780 mg / kg, and the theoretical content of organic chlorine was 112,360 mg / kg. The theoretical content of organic chlorine accounted for approximately 22.97% of the total chlorine, and the theoretical content of inorganic chlorine accounted for approximately 77.03% of the total chlorine.
[0045] The sample was placed in a low-temperature ashing apparatus with the temperature set at 60℃, oxygen pressure at 0.2 mbar, and radio frequency power at 50 W. Low-temperature plasma ashing was performed for 168 hours until constant weight. The residue obtained from low-temperature plasma ashing was placed in the quartz tube of a microcoulometric analyzer at a temperature set at 1000℃, and high-purity oxygen (99.9%) was introduced. After high-temperature pyrolysis, the residue was transferred to the electrolytic cell of the microcoulometric analyzer. The generated chloride ions were dissolved using a 12.2 mol / L acetic acid solution. After titration, the inorganic chlorine content in the mixed model compound was found to be 376,678 mg / kg. Based on the total chlorine content of 489,140 mg / kg, the organic chlorine content was found to be 112,462 mg / kg. The organic chlorine content accounted for approximately 22.99% of the total chlorine, and the inorganic chlorine content accounted for 77.01%. The actual measured results of this method are basically consistent with the theoretical values.
[0046] Example 7
[0047] Sodium chloride and calcium chloride were used as inorganic chlorine model compounds, and biphenyl-4-formyl chloride and thiobis(dichlorophenol) were used as organic chlorine model compounds. They were mixed in a mass ratio of 1:1:2:1. At this time, the theoretical content of inorganic chlorine in the sample was 249060 mg / kg, and the theoretical content of organic chlorine was 145080 mg / kg. The theoretical content of organic chlorine accounted for approximately 36.81% of the total chlorine, and the theoretical content of inorganic chlorine accounted for approximately 63.19% of the total chlorine.
[0048] The sample was placed in a low-temperature ashing apparatus with the temperature set at 60℃, oxygen pressure at 0.2 mbar, and radio frequency power at 50 W. Low-temperature plasma ashing was performed for 168 hours until constant weight. The residue obtained from low-temperature plasma ashing was placed in the quartz tube of a microcoulometric analyzer, with the temperature set at 1000℃ and 99.9% pure oxygen introduced. After high-temperature pyrolysis, the residue was transferred to the electrolytic cell of the microcoulometric analyzer. The generated chloride ions were dissolved using a 12.2 mol / L acetic acid solution. After titration, the inorganic chlorine content in the mixed model compound was found to be 249,000 mg / kg. Based on the total chlorine content of 394,140 mg / kg in the sample, the organic chlorine content was found to be 145,140 mg / kg. The organic chlorine content accounted for approximately 36.82% of the total chlorine, and the inorganic chlorine content accounted for 63.18%. The actual measured results of this method are basically consistent with the theoretical values.
[0049] Example 8
[0050] Sodium chloride and calcium chloride were used as inorganic chlorine model compounds, and biphenyl-4-formyl chloride and thiobis(dichlorophenol) were used as organic chlorine model compounds. They were mixed in a mass ratio of 1:1:1:2. At this time, the theoretical content of inorganic chlorine in the sample was 249060 mg / kg, and the theoretical content of organic chlorine was 192000 mg / kg. The theoretical content of organic chlorine accounted for approximately 43.53% of the total chlorine, and the theoretical content of inorganic chlorine accounted for approximately 56.47% of the total chlorine.
[0051] The sample was placed in a low-temperature ashing apparatus with the temperature set at 60℃, oxygen pressure at 0.2 mbar, and radio frequency power at 50 W. Low-temperature plasma ashing was performed for 168 hours until constant weight. The residue obtained from low-temperature plasma ashing was placed in the quartz tube of a microcoulometric analyzer, with the temperature set at 1000℃ and 99.9% pure oxygen introduced. After high-temperature pyrolysis, the residue was transferred to the electrolytic cell of the microcoulometric analyzer. The generated chloride ions were dissolved using a 12.2 mol / L acetic acid solution. After titration, the inorganic chlorine content in the mixed model compound was found to be 249,000 mg / kg. Based on the total chlorine content of 441,060 mg / kg, the organic chlorine content was found to be 192,060 mg / kg. The organic chlorine content accounted for approximately 43.55% of the total chlorine, and the inorganic chlorine content accounted for 56.45%. The actual measured results of this method are basically consistent with the theoretical values.
[0052] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A method for analyzing organic and inorganic chlorine in coal, characterized in that, Includes the following steps: The total chlorine content in coal was determined using microcoulometric analysis. Organic chlorine in coal is removed by low-temperature plasma ashing to obtain residue; the chlorine content in the residue is determined by microcoulometric analysis, which is the inorganic chlorine content in the coal. The content of organic chlorine in coal = the content of total chlorine in coal - the content of inorganic chlorine in coal; The parameters for the low-temperature plasma ashing are set as follows: temperature 50~60℃, oxygen pressure not exceeding 0.2mbar, radio frequency power 50~100W, and ashing time 72~168h.
2. The analytical method for organic and inorganic chlorine in coal according to claim 1, characterized in that, The combustion temperature in the microcoulometric analysis is 900~1000℃.
3. The analytical method for organic and inorganic chlorine in coal according to claim 1, characterized in that, The titratable chloride ions generated by the microcoulometric analysis are dissolved in a 12.2 mol / L acetic acid solution.
4. The analytical method for organic and inorganic chlorine in coal according to claim 1, characterized in that, The low-temperature plasma ashing is achieved using a low-temperature ashing apparatus; the microcoulomb analysis is achieved using a microcoulomb analyzer.