Improvement And Application Of An Automatic Control Method For MSW Incinerator In Power Plant

With the rapid urbanization,the quantity of municipal refuse will be more and more.The practice has proven that burning rubbish in an incinerator is one way to take care of garbage.With the improving of management in environmental protection from the state,the waste incineration industry is facing to a high standard construction and operation stage.Then the automatic combustion control of refuse incineration is incorporated into the enterprise rating standard.It is difficult to control municipal solid waste(MSW)combustion automatically,and the effectiveness of control method is the key.Therefore,it is of theoretical and practical significance to improve the automatic control method of MSW incineration generator.Firstly,an improved method of furnace-temperature control is proposed.According to the control method of the pure logic comparison between the original furnace-temperature and the set value,the change rate of the controlled temperature is introduced.The stoker action order can be issued in advance,which makes up for the deficiency of waste combustion lag and control lag.In order to solve the problem of large fluctuation of waste calorific value,it is added that the total air volume will adjust the combustion oxygen quantity when the controlled-temperature deviation is large,And a control improvement method is introduced that a small change of primary air volume and secondary air volume adjust the combustion quickly,which makes up for the deficiency that the controlled-temperature fluctuates greatly when the waste calorific value fluctuates greatly only by the stoker action controlling.Secondly,an improved method of boiler-load control is proposed.In view of the original control method which adopts the pure logic comparison between the controlled-load and its set value,the change rate of the drum pressure is introduced.Through the improved method of calculating the deviation of the controlled load and the change rate of the drum pressure and direction,the stoker action instructions can be issued in advance,which makes up for the shortage of control lag in MSW combustion.In order to solve the problem of large fluctuation of waste calorific value,it is added that the total air volume will adjust the combustion oxygen quantity when the controlled-load deviation is large.And a control improvement method is introduced that a small change of primary air volume and secondary air volume adjust the combustion quickly,which makes up for the deficiency that the controlled-load fluctuates greatly when the waste calorific value fluctuates greatly only by the stoker action controlling.Thirdly,an improved method to control the thickness of the material layer is proposed.According to the method of judging the thickness of material layer only by primary air pressure difference,the improved method is introduced that the thickness state of the material layer is judged by the primary air volume and the primary air pressure difference.Aiming at the method of controlling the thickness of the whole material layer through the feeder running distance,the control improvement method is introduced that to feeder speed is adjusted by the layer thickness state of dry section layer,which makes up for the deficiency that the feeder cannot control the feed flow effectively.An improved control method is added that the stoker speed of the cinder section is adjusted by the layer thickness state of the burning embers,which makes up for the deficiency of uncontrolled influence of the fuel layer on the thickness of the combustion section,which makes up for the lack of control over the thickness of the fuel layer in the embers.The improved control method is used in a waste incineration power generation project in Huiyang.Good results have been obtained and the whole operation process of the incinerator is more stable.It can better meet the incinerator constant furnace-temperature or constant boiler-load operation requirements,but also lay the foundation for high standard operation.