Online monitoring system for sodium and chlorine in high-sodium coal pyrolysis gasification gas

Abstract

The utility model discloses an on-line monitoring system for sodium chloride in high-sodium coal pyrolysis gasification gas. The on-line monitoring system comprises a pre-cooling dust removal unit, a flow meter, a condensation trapping unit, a first collection unit, a second collection unit and a comprehensive analysis unit, the pre-cooling dust removal unit is sequentially connected with the flowmeter and the condensation trapping unit and then is divided into two paths, one path is connected with the first collecting unit, and the other path is connected with the second collecting unit; the first collecting unit is used for respectively absorbing organic sodium chlorine compounds and inorganic sodium chlorine compounds in tar; the second collecting unit is used for respectively absorbing organic sodium chlorine compounds and inorganic sodium chlorine compounds in the gas; and finally, respectively mixing the organic sodium-chlorine absorption liquid and the inorganic sodium-chlorine absorption liquid collected from the tar and the gas through a mixer, and carrying out final determination through a comprehensive analysis unit. The device can adapt to a high-sodium coal pyrolysis gasification process in a high-temperature and high-dust environment, and can efficiently and accurately realize on-line monitoring of sodium and chlorine in high-temperature coal gas.

Description

TECHNICAL FIELD

[0001] The utility model relates to the gas component analysis and monitoring technical field of coal chemical industry process especially relates to a kind of sodium chlorine on-line monitoring system in high-sodium coal pyrolysis gasification gas. BACKGROUND

[0002] High-sodium coal releases a large amount of sodium and chlorine compounds during pyrolysis and gasification, which not only causes serious corrosion to equipment such as pipelines and heat exchangers, but also affects the purity of subsequent products. In addition, sodium and chlorine compounds easily form complex compounds with other substances under high temperature conditions, increasing the difficulty of dust removal, desulfurization and other treatments. Therefore, how to effectively monitor sodium and chlorine compounds in high-temperature coal gas is one of the technical problems in coal chemical process control.

[0003] For the determination of sodium and chlorine content in coal, the commonly used methods are combustion and extraction. For example, the Chinese patent document with publication number CN108663405A discloses a detection method for rapid determination of chlorine content in coal by oxygen bomb combustion. The Chinese patent document with publication number CN106769378A discloses a solution extraction method for accurate determination of organic sodium content in high-sodium coal.

[0004] Currently, research on high-sodium coal mainly focuses on the detection of sodium and chlorine compounds during combustion, and the detection methods mostly use laboratory offline analysis. However, there is insufficient monitoring and related research on sodium and chlorine compounds during coal pyrolysis. By cooling and filtering the coal gas sample, conventional detection methods are used for analysis. This method can obtain high-precision results, but due to the need for sample transportation and pretreatment, there is a significant time delay in the analysis results, making it difficult to meet the needs of rapid adjustment during coal gasification. Some studies have also attempted to use spectroscopic methods (such as Fourier transform infrared spectroscopy FTIR) for online monitoring of sodium and chlorine components, but due to the complex conditions of high temperature and high dust, multiple component analysis is also needed, i.e. combining gas chromatography (GC), mass spectrometry (MS) and other equipment, through sample cooling and sampling, to analyze the complex components in high-temperature coal gas. However, the simultaneous analysis technology for organic and inorganic components is still not mature.

[0005] Based on the above research, the present stage of high sodium coal research process exists problems such as complex sample treatment, complex types and various forms of sodium and chloride compounds in coal gas after pyrolysis and gasification (including organic, inorganic, gas phase and particulate state, etc.), which are difficult to be comprehensively detected by a single method; sample collection and cooling process may also lead to the transformation or loss of sodium salt and chloride, thereby affecting the detection results. There is a problem of poor environmental adaptability. The high-temperature coal gas is often accompanied by tar, particulate matter and other impurities, which will cause blockage and pollution to the sampling equipment and analysis instrument; and in the high-temperature, high-dust and high-corrosion environment, the running stability and maintenance cost of the online monitoring device become the bottleneck. The combined technology is not mature, and the various forms of sodium and chlorine determine that multiple technologies (such as ICP-OES, IC, GC-MS, LC-MS, etc.) need to be combined for comprehensive analysis, but there is still a lack of efficient and integrated combined analysis device at home and abroad. Practical new type content

[0006] The utility model provides a kind of sodium chlorine online monitoring system in high sodium coal pyrolysis gasification gas, can adapt to high sodium coal pyrolysis gasification process of high-temperature high dust environment, can efficiently, accurately realize the online monitoring of sodium chlorine in high-temperature coal gas.

[0007] A kind of sodium chlorine online monitoring system in high sodium coal pyrolysis gasification gas, including precooling dust removal unit, flowmeter, condensation trapping unit, first collection unit, second collection unit and comprehensive analysis unit;

[0008] The outlet of the precooling dust removal unit is sequentially connected with the flowmeter and the condensation trapping unit, and then divided into two paths, one of which is connected with the inlet of the first collection unit through a tar pipeline, and the other is connected with the inlet of the second collection unit through a gas pipeline;

[0009] The first collection unit is used for absorbing organic sodium chloride compounds and inorganic sodium chloride compounds in tar in different absorption devices respectively, and the second collection unit is used for absorbing organic sodium chloride compounds and inorganic sodium chloride compounds in gas in different absorption devices respectively;

[0010] The liquid outlets at the bottoms of all absorption devices for absorbing organic sodium chloride compounds are connected through pipelines, and then connected with corresponding organic sodium chloride analysis devices in the comprehensive analysis unit through a first mixer; the liquid outlets at the bottoms of all absorption devices for absorbing inorganic sodium chloride compounds are connected through pipelines, and then connected with corresponding inorganic sodium chloride analysis devices in the comprehensive analysis unit through a second mixer.

[0011] Further, the precooling dust removal unit comprises a heat exchanger and a dust filter connected with each other. The temperature of gas is preliminarily reduced to reach the optimal working temperature of the filter, so as to ensure that particulate matter and other impurities in coal gas are removed.

[0012] Further, the first collecting unit comprises organic solvent absorption device and acid digestion absorption device connected in series, wherein the organic solvent absorption device is used for absorbing organic sodium chloride compounds in the tar, and the acid digestion absorption device is used for absorbing inorganic sodium chloride compounds in the tar.

[0013] Firstly, the organic sodium chloride compounds are absorbed by organic solvents (such as acetone, etc.), and secondly, the inorganic sodium chloride compounds which are difficult to be directly extracted from the tar are absorbed by acid digestion (such as nitric acid, etc.).

[0014] Further, the second collecting unit comprises first absorption device, second absorption device, third absorption device and fourth absorption device connected in series, and the fourth absorption device is externally connected with an air extractor through a pipeline.

[0015] The first absorption device, the second absorption device and the fourth absorption device are used for absorbing inorganic sodium chloride compounds in the gas, and the third absorption device is used for absorbing organic sodium chloride compounds in the gas.

[0016] Alternatively, deionized water is arranged in the first absorption device, dilute nitric acid solution is arranged in the second absorption device, ethanol-water mixed solution is arranged in the third absorption device, and dilute potassium hydroxide solution is arranged in the fourth absorption device.

[0017] The second collecting unit is used for collecting different forms of sodium chloride compounds in the gas by using multi-stage absorption mode, and sequentially passing through the first absorption device (deionized water) for capturing inorganic sodium (such as NaCl and Na2CO3) and inorganic chlorine (such as HCl), the second absorption device (dilute nitric acid solution) for further dissolving inorganic sodium salt which is difficult to be dissolved and capturing part of organic chlorine compounds which have weak polarity, the third absorption device (ethanol-water mixed solution) for dissolving organic sodium (such as sodium soap) and organic chlorine compounds (such as chlorinated aromatic hydrocarbons) in the coal gas, and the fourth absorption device (dilute potassium hydroxide solution) for capturing remaining acidic gas components (such as hydrogen chloride) and converting them into potassium salt.

[0018] Further, the comprehensive analysis unit comprises inorganic sodium chloride analysis device and organic sodium chloride analysis device; the inorganic sodium chloride analysis device comprises ion plasma emission spectrometer and ion chromatograph; and the organic sodium chloride analysis device comprises gas chromatography-mass spectrometry analyzer and liquid chromatography-mass spectrometry analyzer.

[0019] Among them, ICP-OES (ion plasma emission spectrometer) is used to analyze the content of sodium and chlorine in inorganic absorption liquid, and has high sensitivity and the ability of simultaneous analysis of multiple elements; IC (ion chromatograph) is used to determine the content of sodium ion (Na + ) and chlorine ion (Cl -), further improve the detection accuracy of inorganic sodium and chlorine; GC-MS (gas chromatography-mass spectrometry analyzer) is used to analyze organic sodium and organic chlorine compounds in gas or volatile absorption liquid, identify molecular structure and perform quantitative analysis; LC-MS (liquid chromatography-mass spectrometry analyzer) is used to detect difficult-to-volatile, high-boiling organic sodium and organic chlorine compounds, and supplement the deficiencies of GC-MS detection.

[0020] The comprehensive analysis unit also includes a data analysis output module, which, in combination with the flow meter configured in the pipeline, monitors the coal gas flow rate in real time, and the detection results of each analysis device are summarized and analyzed through a data integration system to output the concentration change data or curve of sodium and chlorine compounds and related process parameters.

[0021] The method for monitoring the sodium and chlorine in the high-sodium coal pyrolysis gasification gas using the above-mentioned online monitoring system includes the following steps:

[0022] S1. The high-temperature pyrolysis gasification gas generated by the pyrolysis gasification of high-sodium coal is first introduced into a pre-cooling and dust removal unit for cooling and dust removal.

[0023] S2. After cooling and purification, the pyrolysis gasification gas is measured by a flow meter and then introduced into a condensation trapping unit for deep condensation to realize gas-liquid separation.

[0024] S3. The tar and gas separated from the pyrolysis gasification gas are processed through a first collection unit and a second collection unit, respectively, to collect organic sodium, inorganic sodium, organic chlorine and inorganic chlorine compounds in the tar and gas into solvents.

[0025] S4. The solutions of inorganic sodium and chlorine compounds collected in the first and second collection units are mixed.

[0026] S5. The mixed inorganic sodium and chlorine compound solution and the mixed organic sodium and chlorine compound solution are sent to a comprehensive analysis unit for concentration analysis of different forms of sodium and chlorine compounds.

[0027] Preferably, in step S2, the working temperature of the condensation trapping unit is stabilized at -5℃ to -15℃ to completely collect low-boiling and medium-boiling tar components.

[0028] The condensation trapping unit is composed of multiple condensation devices. According to different components in the tar, the light components and heavy components in the tar are fully condensed through multiple deep condensations. Among them, the organic component sodium and chlorine compounds are distributed in the low-boiling to medium-boiling tar components, and the high-boiling tar components are condensed; through the design of the condensation temperature of -5℃ to -15℃, the low-boiling and medium-boiling tar components are completely collected, which facilitates the collection of organic sodium and chlorine compounds in the subsequent tar sodium and chlorine compound collection unit.

[0029] Compared with the prior art, the utility model has the following beneficial effects:

[0030] 1, the utility model discloses the on -line monitoring of sodium and chloride compound to the coal gas produced in the coal pyrolysis process, and the technology of monitoring the particulate matter or pollutant in the coal combustion process is different from the present stage. Supplement the technology of complex gas phase component trapping and quantitative analysis in the coal gasification process, and the range of monitoring application is expanded.

[0031] 2. The utility model discloses the technology of ICP -OES, IC, GC -MS and LC -MS etc. are used in combination, realize the synchronous analysis to various form compounds. Compared with the current detection technology, the data comprehensiveness and reliability are improved significantly.

[0032] 3. The utility model discloses the method for adopting segmented condensation to combine multistage chemical absorption in the monitoring process, ensures the comprehensive trapping of sodium and chloride compound, avoids the component transformation or loss, and greatly improves the trapping efficiency of complex component and the subsequent analysis precision.

[0033] 4. The utility model discloses the on -line monitoring flow, improves the analysis efficiency. Through multimodule data integration, the concentration change of sodium chloride compound is obtained completely. Compared with traditional offline analysis, the data delay is reduced significantly and more timely process feedback is provided. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is the structural diagram of the utility model of a kind of sodium chloride on -line monitoring system in high sodium coal pyrolysis gasification gas.

[0035] In the drawing: 1-precooling dust removal unit, 2-heat exchanger, 3-dust filter, 4-flow meter, 5-condensation trapping unit, 6-first collection unit, 7-organic solvent absorption device, 8-acid digestion absorption device, 9-second collection unit, 10-primary absorption device, 11-secondary absorption device, 12-tertiary absorption device, 13-quaternary absorption device, 14-air extractor, 15-mixer, 16-comprehensive analysis unit, 17-switching valve. DETAILED DESCRIPTION

[0036] The utility model will be further described in detail below in combination with drawing and example, it needs to point out that the following described example is aimed at facilitating the understanding of the utility model, and it does not have any limiting effect on it.

[0037] As Figure 1 Indicated, a kind of sodium chloride on -line monitoring system in high sodium coal pyrolysis gasification gas, including precooling dust removal unit 1, flow meter 4, condensation trapping unit 5, first collection unit 6, second collection unit 9 and comprehensive analysis unit 16. Pyrolysis gasification gas flows through pipeline and takes insulation or heat tracing measure.

[0038] The pre-cooling and dust-removing unit 1 comprises a heat exchanger 2 and a dust filter 3 connected with each other. In the pre-cooling and dust-removing unit 1, the pyrolysis gasification gas is preliminarily cooled in the heat exchanger 2 through an adiabatic pipeline to meet the working conditions of the dust filter 3. The particulate matters in the gas are removed through the dust filter 3.

[0039] The outlet of the pre-cooling and dust-removing unit 1 is connected with a flow meter 4 and a condensation and trapping unit 5 in sequence and then divided into two paths, one of which is connected with the inlet of a first collecting unit 6 and the other of which is connected with the inlet of a second collecting unit 9.

[0040] The condensation and trapping unit 5 is designed in a sectional condensation manner. The pyrolysis gasification gas is subjected to sectional deep condensation to trap the tar components in the gas, and then the tar and sodium chloride compounds in the gas are collected through the first collecting unit 6 and the second collecting unit 9.

[0041] Specifically, the first collecting unit 6 comprises an organic solvent absorption device 7 and an acid digestion absorption device 8 connected in series, wherein the organic solvent absorption device 7 (the solvent can be acetone, etc.) is used to absorb the organic sodium chloride compounds in the tar, and the acid digestion absorption device 8 (the absorption liquid can be nitric acid, etc.) is used to absorb the inorganic sodium chloride compounds in the tar.

[0042] The second collecting unit 9 comprises a first absorption device 10, a second absorption device 11, a third absorption device 12 and a fourth absorption device 13 connected in series, and the fourth absorption device 13 is externally connected with an air extractor 14 through a pipeline. The first absorption device 10, the second absorption device 11 and the fourth absorption device 13 are used to absorb the inorganic sodium chloride compounds in the gas, and the third absorption device 12 is used to absorb the organic sodium chloride compounds in the gas.

[0043] The organic sodium, inorganic sodium, organic chlorine and inorganic chlorine in the gas are subjected to the steps of absorbing different compounds in sections, so that different types of sodium and chlorine compounds in the gas sample are absorbed in different solutions. The inorganic sodium (such as NaCl, Na2CO3) and inorganic chloride are preliminarily absorbed through the first absorption device 10 (deionized water); the remaining inorganic sodium and inorganic chloride are further absorbed through the second absorption device 11 (dilute nitric acid solution) to decompose certain organic sodium and organic chloride compounds; the organic sodium and organic chloride compounds are dissolved through the third absorption device 12 (ethanol-water mixed solution); and the acidic chloride such as hydrogen chloride is trapped through the fourth absorption device 13 (dilute potassium hydroxide solution). The air pressure of the collecting device is balanced through the air extractor 14. Finally, the organic sodium chloride absorption liquid and the inorganic sodium chloride absorption liquid collected from the tar and the gas are respectively mixed through a mixer 15, and then sent into a comprehensive analysis unit 16 through two pipelines with valves. A switching valve 17 is arranged between the two pipelines to switch as required.

[0044] The comprehensive analysis unit 16 mainly includes an inductively coupled plasma optical emission spectrometer (ICP-OES), an ion chromatograph (IC), a gas chromatograph-mass spectrometer (GC-MS), and a liquid chromatograph-mass spectrometer (LC-MS). For inorganic sodium and inorganic chlorine, inorganic sodium (such as Na + ) and inorganic chlorine (such as Cl - ) are measured with high sensitivity by inductively coupled plasma optical emission spectrometry (ICP-OES); inorganic sodium (Na + ) and chlorine ions (Cl - ) are separated and quantitatively measured by ion chromatography (IC). For organic sodium and organic chlorine, gas chromatography-mass spectrometry (GC-MS) is used to separate and detect the types and contents of organic sodium and organic chlorine compounds, and liquid chromatography-mass spectrometry (LC-MS) is used for supplementary measurement. That is, ICP-OES / ICP-MS and GC-MS / LC-MS are used for analysis, so that each component can be accurately quantified, and finally the content data of sodium and chlorine components in the pyrolysis gasification gas can be obtained.

[0045] The above-described embodiments describe the technical solutions and beneficial effects of the present application in detail. It should be understood that the above-described embodiments are only specific embodiments of the present application and are not intended to limit the present application. Any modifications, supplements, and equivalent replacements made within the principle range of the present application should be included in the protection range of the present application.

Claims

1. A system for on-line monitoring of sodium chloride in a high-sodium coal pyrolysis gasification gas, characterized by, The pre-cooling dust removal unit (1), the flow meter (4), the condensation trapping unit (5), the first collection unit (6), the second collection unit (9) and the comprehensive analysis unit (16) are included. The outlet of the pre-cooling dust removal unit (1) is connected with the flow meter (4) and the condensation trapping unit (5) in sequence and then divided into two paths, one of which is connected with the inlet of the first collection unit (6) and the other of which is connected with the inlet of the second collection unit (9). The first collection unit (6) is used for absorbing the organic sodium chloride compound and the inorganic sodium chloride compound in the tar in different absorption devices respectively, and the second collection unit (9) is used for absorbing the organic sodium chloride compound and the inorganic sodium chloride compound in the gas in different absorption devices respectively. The bottom liquid outlets of all the absorption devices for absorbing the organic sodium chloride compound are converged through a pipeline and connected with the corresponding organic sodium chloride analysis device in the comprehensive analysis unit through a first mixer, and the bottom liquid outlets of all the absorption devices for absorbing the inorganic sodium chloride compound are converged through a pipeline and connected with the corresponding inorganic sodium chloride analysis device in the comprehensive analysis unit through a second mixer.

2. The on-line monitoring system for sodium chloride in high-sodium coal pyrolysis gasification gas according to claim 1, characterized in that, The pre-cooling dust removal unit (1) comprises a heat exchanger (2) and a dust filter (3) connected with each other.

3. The on-line monitoring system for sodium chloride in high-sodium coal pyrolysis gasification gas according to claim 1, characterized in that, The first collection unit (6) comprises an organic solvent absorption device (7) and an acid digestion absorption device (8) connected in series, wherein the organic solvent absorption device (7) is used for absorbing the organic sodium chloride compound in the tar, and the acid digestion absorption device (8) is used for absorbing the inorganic sodium chloride compound in the tar.

4. The on-line monitoring system for sodium chloride in high-sodium coal pyrolysis gasification gas according to claim 1, characterized in that, The second collection unit (9) comprises a first absorption device (10), a second absorption device (11), a third absorption device (12) and a fourth absorption device (13) connected in series, and the fourth absorption device (13) is externally connected with an air extractor (14) through a pipeline. The first absorption device (10), the second absorption device (11) and the fourth absorption device (13) are used for absorbing the inorganic sodium chloride compound in the gas, and the third absorption device (12) is used for absorbing the organic sodium chloride compound in the gas.

5. The on-line monitoring system for sodium chloride in high-sodium coal pyrolysis gasification gas according to claim 4, characterized in that, Deionized water is arranged in the first absorption device (10), dilute nitric acid solution is arranged in the second absorption device (11), ethanol-water mixed solution is arranged in the third absorption device (12), and dilute potassium hydroxide solution is arranged in the fourth absorption device.

6. The on-line monitoring system for sodium chloride in high-sodium coal pyrolysis gasification gas according to claim 1, characterized in that, The comprehensive analysis unit comprises an inorganic sodium chloride analysis device and an organic sodium chloride analysis device, the inorganic sodium chloride analysis device comprises an ion plasma emission spectrometer and an ion chromatograph, and the organic sodium chloride analysis device comprises a gas chromatograph-mass spectrometer analyzer and a liquid chromatograph-mass spectrometer analyzer.

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