The Experimental Studies Of The Direct Igniting Pulverized Coal On The Theory Of Medium-frequency Induction Heating

In power stations, Great mount of diesel oil has been consumed at beginning of boiler running or in low-load period. The technology of direct igniting pulverized coal is the most effective method of saving diesel oil and cost reduction in power stations.The system experiment research of direct igniting pulverized coal have been done by two methods of hot-wall ignition and high temperature air(HTA) ignition, which are heated by medium-frequency introduction-heating.In the research of the hot-wall ignition heated by introduction-heating, the experiments have been done about the influencing of pulverized coal concentration, coal species and combustor structure to pulverized coal ignition and combustion, numerical simulation has been done, and the mode of ignition has been discussed. At last, multi-stage ignition has been realized on the130t/h medium-pressure boiler of a power station.A new style HTA generator has been invented through combination of SV static mixer and introduction heater. The experiments have been done about characteristic of flow-drag and electricity, heating efficient. The result shows the new style HTA generator not only can reach the requirement of the HTA ignition pulverized coal but also have virtues of high efficiency, simple structure, high reliability.Then, a new style HTA ignition combustor has been invented, and its experimental system has been built, and a great mount of experiments have been done. Shenhua blending coal and Yanzhou bituminite have been used.First, on the purpose of industrial design and application, experiments have been done about influencing of physical dimensions on ignition temperature; the physical dimensions have been decided according to the experiment results and coal species. The influencing factors of ignition and flameout HTA temperatures have been experimented by use of different size pulverized coal, and numerical simulation of interior flow field of the HTA ignition combustor has been done. Their results all can show that design of the new style HTA ignition combustors is succeed in way of ignition pulverized coal and safe operation, can prevent the combustor from coking and excess temperature. Second, on the purpose of the mode of pulverized coal ignition and combustion in HTA, fore and after appearance of homogeneous flame, the change of the porosity structure, consumption of volatile and char, particle sizes distribution of pulverized coal and component of flue-gas at the combustor outlet have been measured as the change of the HTA temperature, the results show the most of pulverized coal. The results reveal the process before and after different size pulverized coal being igniting in high temperature and turbulent flowing air.The same experiments have been done on the Dongbei lean coal, the results have been compared with bituminite.The HTA multi-stage ignition combustor has been invented, and its experimental system has been built. The influencing factors of ignition and combustion have been experimented in the combustor, the results show the invention of the HTA multi-stage ignition combustor is succeed.