Study On Closed Loop Automatic Control Of Dense Medium Ash Content In Guobei Coal Preparation Plant

As a big country of energy production and consumption,coal occupies an unshakable position in Chinafs energy policy,and is also the key to the rapid development of our national economy.Therefore,the development of coal preparation technology and the improvement of coal quality and utilization rate have become the key to the sustainable and healthy development of the coal industry.With the continuous improvement of the level of industrial automation in China,the hardware and software technology of coal preparation process are also constantly innovating and developing,and the application of automation technology in coal preparation industry is also more and more in-depth.From the initial simple monitoring of plant and equipment to the automatic control of various process parameters,automation technology has had a profound impact on coal preparation.As the most efficient coal preparation technology nowadays,dense medium coal preparation is widely used in coal preparation industry.Gravity separation mainly relies on density control of suspension,which is based on Archimedes principle.Therefore,precise control of suspension density has become a key factor for the effect of gravity separation.In the whole process of gravity separation,the process parameters need to be continuously tested,updated and adjusted.There are many factors affecting the density of heavy medium suspension,which are not only related to ash content of clean coal,but also closely related to ash content of raw coal,washing amount of raw coal and liquid level.So the setting and adjustment of suspension density need to be considered comprehensively in many aspects.At present,most coal preparation plants,including Vobei coal preparation plant,rely on manual control,but this control method has many defects.Firstly,the ash content of cleaned coal products by manual testing is used as the basis of inspection and regulation,which is not real-time enough to detect the process adjustment errors in time,resulting in the reduction of production rate,which is a loss for the benefit of coal washery.And there will be differences between different teams and different staff in the process of equipment operation,which will also cause the fluctuation of ash content in clean coal.At the same time,the objective factors such as strong workload of operators and bad environment also affect the normal and stable operation of the whole coal preparation process.In view of the above shortcomings of manual operation,the artificial ash detection method of Vobei Coal Preparation Plant was developed into a closed-loop automatic control system for ash content of dense medium separation clean coal.To overcome the shortcomings of manual adjustment and interference of working environment.The density of heavy medium suspension is stable and accurate,and the coal preparation efficiency is greatly improved.Figure 24 table 5 reference 55...