Online coal ash content measurement system and method based on natural gamma rays

Abstract

The invention relates to an online coal ash content measurement technique and particularly relates to an online coal ash content measurement system and method based on natural gamma rays. The online coal ash content measurement system comprises a shielding body, a gamma ray detector, an electronic belt scale, an energy spectrum analysis and processing instrument and a host, wherein the shielding body packages the exterior of a coal conveying belt; the gamma ray detector is distributed right below the coal conveying belt; the coal conveying belt is distributed on a coal conveying belt stander; the electronic belt scale is distributed on the coal conveying belt stander; the gamma ray detector and the electronic belt scale are respectively connected with the energy spectrum analysis and processing instrument through a signal wire; the energy spectrum analysis and processing instrument is connected with the host by a data line. According to the online coal ash content measurement system based on the natural gamma rays, a calculation coefficient is determined by virtue of a static calibration process which is carried out when a belt is stopped, and only a high-limit coal sample and a low-limit coal sample are required; compared with an active ash content instrument with a dynamic sampling calibration process, the online coal ash content measurement system has the advantages that the operation is easy and safe, a few varieties of coal samples are required, the weight is light, and the manpower, material resources and financial resources of users are greatly saved.

Description

technical field [0001] The invention relates to an online measurement technology of coal ash, in particular to a system and method for online measurement of coal ash based on natural gamma rays. Background technique [0002] Coal ash content is the mass fraction of high atomic number oxide residues after coal is fully and completely burned at a certain temperature (that is, weight percentage, denoted as Ad%). Coal ash content is closely related to the calorific value of coal, and it is one of the main indicators for evaluating coal quality. In order to improve the utilization efficiency of coal, the ash content of coal products must be strictly controlled. However, the traditional igniter test method has complex procedures and long lag time in giving results, which cannot meet the needs of coal product quality control and cannot perform real-time control, which is not conducive to the full utilization of coal resources. Therefore, in coal processing and utilization, there i...

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Problems solved by technology

Because the dual-energy gamma ray transmission ash analyzer uses two radioactive sources, out of safety considerations, my country's current laws and regulations have strict regulations on the use of radioactive substances, and users need to be approved by environmental protection, public security, health and other departments. It can only be used after filing. During use, it is necessary to carry out dedicated management of radioactive sources to prevent radioactive leakage, pollute the environment and endanger human health, so it is very inconvenient for users. On the other hand 241 Am radioactive sources are heavily dependent on imports, the cost is high, and the supply cycle is not guaranteed

Moreover, the principle of the dual-energy ash measurement method has its inherent shortcomings: the dual-energy method belongs to single-point measurement, such as figure 1 The online ash analyzer shown: the radioactive source 1 is a point source that emits conical gamma rays, and the detector 2 can only measure the ash content of the coal flow 3 in the scanned 3-5cm wide area, which is easily affected by the belt 4 cross-section. The influence of uneven distribution of coal flow, the measurement results have great limitations, and the ash content is poorly represented

However, the disadvantage is that only the qualitative relationship between the ash content and the natural radioactivity has been determined but not the quantitative relationship, and the relationship between the coal load parameters and the natural radioactivity intensity has been ignored. This method is not suitable for the occasion of online coal ash measurement.

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