Research Of The New Online Metrological Method And System Of Coal

In order to systematically carry out research work for the different coal online metrological method, a new coal metrological system which used for measuring the weight and calorific value is developed. The system which can simulate the actual coal measurement environment has the advantages of high accuracy、error tracing、online calibration、remote control. Besides electronic belt weigher use new calibration method based on the material superimposed technology to solve the problem of how to keep high measurement accuracy, meanwhile through physical hopper scale to realize error traceability.On the other hand the coal calorific value based on the method of oxygen bomb combustion exist the problem of low measurement efficiency at present, however the new design coal material sampling equipment effectively resolved it.On the basis of these research about coal metrological technology of belt weigher and calorific value, this paper analysis the calibration error mathematical model. Secondly the scheme and mechanical structure of test metrological system is designed and its control part adopts the PC and lower machine plan which PLC combined LABVIEW to realize communication.Then analysis the movement process of designed sampling head by ADAMS software.Finally according to the requirements of relevant national standard and verification regulation which involved belt weigher and calorific value about belt coal,some experiments have been done.Now the developed device has achieved the function of remote operation and measurement data which can transmit through the Internet.Those experimental results show that repetitiveness of the belt weigher calibration system based on superimposed technology is less than 0.2%.And the maximum permissible error can control in the range of 0.5%.This calibration method can reach the requirement of grade 0.5 belt weigher verification regulation while the ratio of theoretical material superimposed is above 50%.Furthermore compared with the calibration results about the method based on superimposed technology andhopper weigher in the different flow, the average calibration difference is 0.11%.In summery this calibration method fully meet the verification regulation of grade 0.5belt weigher during the material flow is less than 7.5t/h.It indicates that the weights superposition method is better than the way of materials superposition.In addition a series of uncertainty assessment were done. The expanded uncertainty of belt weigher calibration system based on the method of superimposed technology is within 0.17%,and the calorific measurement system expanded uncertainty is 38.8J/g.In a word the combined standard uncertainty of coal total energy from metrological system is 164.68 MJ.And the total energy measurement error from coal metrological system is 0.55% through hopper scale error traceability.