The standard deviation of the ash online detection is less than 0.15%, which is used in the intelligent close control system, the recovery rate of clean coal is increased by 0.95%. They did it.

Recently, the intelligent project of Shanxi Coking Coal Group Huajin Coking Coal Company Shaqu Coal Preparation Plant implemented by DFMC, it has made important progress. The high-precision online coal quality analyzer has successfully passed the double verification of the plant-level joint laboratory test and the third-party test. The dynamic standard deviation of the ash content of the laboratory analyzer is 0.11%, the standard deviation of the ash content of the third-party test analyzer of the China Coal Supervision and Inspection Center (Xi'an) is within 0.1%, the high standard has passed the acceptance.

Picture 1 The third-party test report of the China Coal Supervision and Inspection Center (Xi'an)

Picture 2 Pre-acceptance report of plant-level joint laboratory inspection

Although a number of intelligent Dense-medium sorting projects have been implemented in China,but due to the limitations of detection methods, the problems of large ash detection errors and poor stability in the production process have not been solved well, resulting in poor intelligent control effects. It is precisely based on the reality of this industry that the Dense Medium Intelligent Project of Shaqu Coal Preparation Plant, it took the accurate detection of Dense Medium Coal Preparation Ash as one of the key research topics at the beginning of the project and they paid a great attention to it. The coal quality analyzer installed at the Dense-medium coal  preparation process point, it has been regarded as the "heart of the project" during the demonstration and implementation stage of the intelligent research and demonstration application of Shaqu Dense-medium separation.

Picture 3 Real shots of the high-precision coal quality analyzer on-site

Picture 4 Dense medium block coal preparation control interface

The successful application of the high-precision coal quality analyzer solves the problem of accurate ash detection in the process of dense-medium washing in the coal preparation plant, provides accurate ash reference data for the washing control system, makes intelligent control of ash-density possible. As shown in the figure below, the ash content control target setting value is 11.10%. Through the intelligent analysis of the suspension separation density and the ash content of the clean coal, the process lag time T0 and the analyzer capacity lag time T1 are calculated, the system execution cycle T is determined as 15 minutes. The intercepted 6-hour continuous control curve controlled by the intelligent module of the clean coal ash index control of the Coking Coal Dense Medium System. It can be seen from the curve that when the ash content of the heavy-medium clean coal exceeds the limit, the system adjusts the separation density of the dense-medium suspension in time to ensure the stability of the ash data.

Picture 5 Ash data curve of ash return control intelligent system

The coal quality analyzer can also detect iron and sulfur in the coal stream. Through the detected Fe content, the condition of the clean coal with media in the coal preparation process is monitored. According to this data change, the state of the de-intermediation sieving material and the water spray can be judged in time, which adds a new management method for better control and management of the media consumption. It can be seen from the figure below that the Fe content in area B is significantly higher than that in area A. Through the alarm, it is found that the flushing water flow on the clean coal de-intermediation sieve is abnormal, which is less than the conventional set value. After the system is adjusted, the sieve is increased With water flushing, the amount of clean coal belt has been significantly improved, refer to the C area. The precise detection of S content guides the subsequent precise blending of high-S coal.

Picture 6 The analysis instrument detects the fluctuation graph of Fe content in dense medium block coal preparation

Through the application of a high-precision coal quality analyzer and an intelligent close control system, during operation, the ash deviation of the ash return control system is 0.26%, which is 0.44% lower than the traditional manual ash standard deviation (dispatch data), which is 0.18% lower. According to the 4# and 5# coal quality analysis report of Shaqu Coal Preparation Plant, the theoretical recovery rate of clean coal is estimated to increase by 0.95%

Picture 7 Control effect analysis — 4# coal test data

Picture 8 Control effect analysis — 5# coal test data

The lack of accurate and reliable online coal quality detection equipment has always been a shortcoming that restricts the high-quality development of the entire coal preparation industry. This time, the neutron activated coal quality analysis technology is applied to the online detection of dense medium lump clean coal quality, the ash content measurement accuracy. The long-term stay within 0.15% has better solved the industry problem of dense-medium intelligent separation control based on coal quality online detection data and laid the equipment foundation for the construction of a high-level intelligent coal preparation plant.