Research On Engineering Application Of Membrane Method Oxygen-enrichment Local Supporting Combustion Technique On Tetragonal Inscribed Circle Pulverized Coal Boiler

In our country, power boilers mainly consist of pulverized coal boilers, which generally adopt techniques of tangential-firing, rich-lean coal firing and graded combustion technology. Based on a large number of literatures, technique character, status and developing prospect of the boiler were fully discussed in this paper. The tangential-firing pulverized coal boiler will still be of great importance in power boiler in future. Surely, there are still some problems to be solved.To realize the object of economical, environment protective and safe running of boiler, based on rich-lean coal firing technology, computer numeric simulation was used to systematically and intensively study graded combustion technique with object to 150t/h tangential-firing ,solid slag and medium pressure pulverized coal power boiler. The local enriched-oxygen supporting combustion technique for tangential-firing boiler was firstly developed. In this technique, by local enriched-oxygen, oxidizing ambience was realized, graded combustion technique with wanting-oxygen combustion in the furnace chamber facing the fire and enriched-oxygen combustion back to the fire was realized. Finally, safe, high efficient and low NOx emission in the boiler were achieved. Main research contents: (1) Experiment of the cold air dynamical field was done on furnace, and according to property of the designed and calculated coal species, the membrane oxygen-enrichment local supporting combustion system was researched and designed. (2)Hot combustion adjustment experiment was done on furnace to ensure the optimal air mixing mode and method of oxygen-enriched air.(3) Performance test and low load stable combustion without ingoing oil test were done on furnace to examine the running effect of membrane oxygen-enrichment local supporting combustion system in this paper. Results shows that the carbon content in slag and fly ash to be obviously lowered, the thermal efficiency of the boiler to been enhanced, Slag bonding and high temperature corrosion can be effectively prevented. It is also found that NO_x emission could be decreased and the low load stable burning could be improved.