Promotion and application of LIBS coal quality real-time detection technology in the power industry

Overview of research at home and abroad

LIBS (Laser Induced Breakdown Spectroscopy) technology was proposed in the 1960s. It uses ultra-short pulse laser to focus on the surface of the sample to form plasma, and then uses a spectrometer to analyze the plasma emission spectrum to identify the components in the sample. It is a means of identifying, classifying, qualitatively and quantitatively analyzing the elemental composition of materials. This technology can identify and detect almost all elements. It has been widely used in soil composition testing, food safety testing, rock and mineral analysis, and identification of steel, petroleum, plastics, cement, gems, etc. It is also used in the identification of dangerous goods, explosives, and ancient cultural relics. , atmospheric detection, military, marine minerals and microorganisms and many other fields are also involved. In the future, it is expected to replace X-rays and play a huge role in people's production and life. In the economic field, with the deepening of the development strategy of energy conservation and emission reduction, in September 2014, the National Development and Reform Commission, the Ministry of Environmental Protection and the National Energy Administration jointly issued the "Coal Power Energy Conservation and Emission Reduction Upgrade and Transformation Action Plan (2014-2020)". It is clearly stated that in view of the current severe situation facing energy conservation and consumption reduction of thermal power units, the average coal consumption of power supply after the transformation of my country's existing coal-fired power units will be less than 310g/kwh by 2020. How to make optimal combustion control adjustments based on coal quality composition detection data to ensure the best air-to-coal ratio, coal-to-water ratio and power-to-coal ratio, thereby improving boiler combustion efficiency, saving energy and reducing emissions, is an urgent issue currently. my country's LIBS technology has now moved from the laboratory research stage to the practical application stage, that is, real-time online detection technology for the thermal power generation industry - LIBS coal quality real-time detection technology. So far, due to the fluctuation of domestic coal price market conditions and the uncertainty of raw coal collection, coal quality fluctuates greatly, and there are few research reports and cases on its application in online coal quality detection and precise adjustment of combustion optimization. Therefore, this technology has broad application prospects in the power industry. A power plant in Shandong bravely seized new economic growth points in the power technology innovation and became the first domestic power company to apply LIBS coal quality real-time detection technology to achieve thermal power generation. The company still uses manual offline analysis for most coal-fired units. , preparation and conversion take a long time, and the analysis results are lagging. Once the coal quality fluctuates, it is impossible to put oil in time to support combustion or make combustion adjustments. The coal entering the furnace of the 330MW unit under his name has been successfully put into use LIBS real-time coal quality detection. technology. The coal quality online real-time detection system implemented by LIBS coal quality real-time detection technology can display the dynamic stroke of coal flow and all-element indicators of coal quality on the fuel supervision information and publish it on the detection platform in real time, providing optimized and accurate online real-time visualization for boiler combustion. Testing data fundamentally solves many problems that arise in the process of coal-fired power generation and becomes the inevitable direction for future technological innovation in the power industry.

Technical route and application prospects of LIBS coal quality real-time detection technology

2.1 Technical route

The establishment of the technical route of LIBS coal quality real-time detection technology requires multiple steps such as modeling, debugging, and application. First, an integrated LIBS technology online real-time detection system needs to be installed on the coal conveying system to collect anthracite and various types of coal used in the power generation process to make calibration coal samples to establish calibration coal sample spectra. Data model. Such a model needs to undergo repeated debugging training to improve the test accuracy of LIBS technology; secondly, a set of online coal quality analysis and calculation models are established using the big data cloud platform to obtain real-time coal quality analysis data and coal quality index change trends; and then in Basic parameters such as coal feeding belt, raw coal bunker level, coal feeder output, coal grinder output, and pulverizer output are obtained from the DCS of the generating unit. Based on this, a set of coal flow process visualization real-time monitoring of coal burning is developed. system. This system can display, track, query, and analyze the coal quality change trend of the operating unit in real time to facilitate the dynamic monitoring of boiler combustion; again, by realizing the connection between the real-time detection data of coal quality and the dynamic coal flow visualization system, it can guide the boiler combustion in a timely manner. Adjustment improves the economy and stability of the operating unit; the last step is to ensure that the boiler is in the best combustion condition under different coal types and different working conditions through fine adjustment, thereby calculating the final combustion optimization model of the boiler and control strategies. The establishment of the entire technical route is based on the current actual coal burning conditions in the power industry, combined with the big data cloud collection and analysis system, and relying on real-time monitoring and detection devices implemented by information technology to solve various problems that occur in actual coal burning in the power industry. The question is of great importance.

2.2 Application prospects

As an emerging technology applied to the electric power industry, LIBS real-time coal quality detection technology can realize real-time monitoring of coal quality in each pulverizing system, conduct real-time detection of coal quality components and types in coal furnaces, and use the cloud data platform to provide real-time monitoring of coal quality to the electric power industry. The center provides dynamically visualized coal quality online analysis data, thereby realizing real-time online detection of all elemental indicators of coal quality. It can accurately calculate boiler efficiency in real time based on the provided real-time coal quality analysis data, and according to the designed advanced control strategy, it can realize the control of coal furnaces. Online combustion optimization and precise adjustment improve boiler combustion efficiency while improving denitration efficiency and environmental protection indicators. So far, there are very few reports and actual engineering application cases about this technology. However, with the industrial upgrading and structural adjustment in the economic field, the application results of LIBS coal quality real-time detection technology in the power industry will soon be confirmed. Technology has broad practical significance and broad application prospects for industrial upgrading and technological innovation. It is an important way to optimize the industry in the power industry and achieve the development goals of energy conservation and emission reduction. It also plays an important reference and demonstration role in the precise combustion adjustment of coal-fired power generation unit boilers. It promotes the smooth progress of the group company's coal power energy conservation and emission reduction upgrades. Necessary way.

The promotion significance of LIBS coal quality real-time detection technology

LIBS coal quality real-time detection technology can use the big data platform to optimize the designed control strategy based on real-time analysis data and other equipment operating parameters of the generating unit, thereby achieving precise optimization and adjustment of the entire combustion process of the boiler and achieving the best possible outcome of the boiler combustion process. The air-to-coal ratio, power-to-coal ratio and coal-to-water ratio, and no matter how the quality of the coal entering the furnace changes, this technology can always ensure that the boiler combustion is operating under an optimal working condition, eliminating the lag and other problems of manual offline analysis. It can reduce the coal consumption of the boiler to a certain extent and improve the combustion efficiency of the boiler; fundamentally improve the stability of the main steam pressure and steam temperature of the boiler, thereby improving the various indicators of the unit in the AGC mode; it can also ensure the denitrification inlet NOx Relatively stable, improving denitrification efficiency and flue gas emission indicators. If this technology can be vigorously promoted, it may change the way coal is burned as an environmentally harmful fossil energy, making coal clean and efficient and contribute more to economic development.

summary

LIBS coal quality real-time detection technology can use the big data platform to optimize the designed control strategy based on real-time analysis data and other equipment operating parameters of the generating unit, thereby achieving precise optimization and adjustment of the entire combustion process of the boiler and achieving the best possible outcome of the boiler combustion process. The air-to-coal ratio, power-to-coal ratio and coal-to-water ratio, and no matter how the quality of the coal entering the furnace changes, this technology can always ensure that the boiler combustion is operating under an optimal working condition, eliminating the lag and other problems of manual offline analysis. It can reduce the coal consumption of the boiler to a certain extent and improve the combustion efficiency of the boiler; fundamentally improve the stability of the main steam pressure and steam temperature of the boiler, thereby improving the various indicators of the unit in the AGC mode; it can also ensure the denitrification inlet NOx Relatively stable, improving denitrification efficiency and flue gas emission indicators. If this technology can be vigorously promoted, it may change the way coal is burned as an environmentally harmful fossil energy, making coal clean and efficient and contribute more to economic development.