Optimization Of Fixed Bed Intermittent Gas Preparation Process Control System

In view of the inherent defects of Zedong Company's "fixed-bed intermittent coal gasifier"(hereinafter referred to as gasifier),the concept of "intermittent interference" is proposed.On the basis of in-depth study of "intermittent interference",several measures to overcome "intermittent interference" are put forward and implemented,so as to achieve the goal of stabilizing and optimizing the control of gas-making system.Because the original control system is the "Siemens S7-200 series" control system of Delong Company,limited by the capacity of software and hardware of the system,it can not store the relevant information of 10 gas-making furnaces,so the new "JX-300XP" control system of Zhejiang Central Control Technology Co.,Ltd.is added to make it the same as the control system of Delong Company.Step by step and work together.The central control system is responsible for collecting all kinds of data and indicators,judging,processing and summarizing,and then outputting the calculation results to Delong system for output and execution.First of all,it is necessary to find out the internal parameters of the gasifier,namely "gasifier height" and "gasifier temperature".These two parameters can help operators understand the production situation inside the furnace.However,in actual production,it can not be directly measured by the instrument,so the two parameters are finally obtained through the program processing.Secondly,aiming at the problem of "intermittent interference",three schemes are designed: three schemes of thickness adjustment,height compensation of gasification layer and temperature compensation of gasification layer.The formulation of "Three Thickness Adjustment Programs" makes the adjustment means of removing scars and hulls and increasing the thickness of gasifier more flexible,and it is of great help to the increase of gas volume.Through a large number of data acquisition and program processing,the "height of gasification layer" in the gasifier is simulated and controlled inthe optimum position by means of "bottom blowing compensation".The scheme of "gasification layer temperature compensation" was formulated,and the "gasification layer temperature" in the gasifier was simulated through a large number of data acquisition and program processing.Compared with the "height of gasification layer",the "temperature of gasification layer" is more affected by external interference factors,so the treatment method is more complex,resulting in "stop-start compensation","up-fluctuation compensation" and "back-net compensation".The above three schemes can be chosen flexibly for different production situations.Finally,the ratio of hydrogen to nitrogen is one of the most important technological parameters in the process of ammonia synthesis.The quality of its control results is directly related to the production cost.However,this control object has a long lag time of YISHION,many interference factors and strong integral characteristics.Based on the above characteristics,the parameters of "gasification hydrogen,converted hydrogen,circulating hydrogen and circulating methane" detected by DCS system are used to modify the control parameters in time according to the dynamic changes in the production process according to the idea and method of adaptive control,so as to stabilize the hydrogen-nitrogen ratio.It is an innovative attempt to deepen information technology into solid process,transform solid process,overcome the defects of solid process,improve gas production efficiency of solid process,reduce pollutant emission of solid process,so as to achieve the goal of energy saving,emission reduction and benefit improvement.