A Theory Study And System Design Of Chemical Agglomeration For Ultrafine Particulate Matter

Ultrafine particulate matters would cause great harm to the atmosphere of theecological environment and human health and cause widespread concern and attention. Thecontrol of particulate matters emissions is particularly important. While a large number ofultrafine particulate matters are discharged by coal combustion and ESP can hardly meetthe national emission standards, chemical dust agglomeration technology is able to controlthe emissions of ultrafine particulate matters effectively.In this paper, the author put forward using Stephen flow theory to analyze themechanism of chemical agglomeration processes，basing on the theory by chemicalflocculation agglomeration. Stephen streams exist in the chemical agglomeration process,and through the relevant formula to prove the existence and agglomeration agent dropletsfrom Stephen evaporation point to elaborate the role of the process flow of the chemicalimpact of reunion in the turbulent gas flow, Stephen stream can not be neglected.The chemical agglomeration system for the engineering level on the basis of chemicalagglomeration theory can be applied and has broad application prospects, but the designwork of the system has rarely been done. From a practical point of view，the design work ofchemical agglomeration system has been carried out. Based on the given parameters, thepilot calculation of the rate of solution consumption firstly be done, and then the authorhave calculated the rate on the set temperature in the premise, with the flue temperaturehigh or low of different coal-fired boiler, while the solution temperature changes, the ratechanges. To determine the dosage range, the risk of low-temperature corrosion will likelybe took into account.While the solution dosage range as the system design constraint conditions, the authorhave determined the location chemical agglomeration system and the preliminary layout ofthe nozzle groups, and have calculated the parameters of the main channel of the solution,in order to provide the basis for the selection of the subsequent equipments and so on.On considering the consumption rate of the solution, the equipments of the systemhave been selected, such as the powder feeding equipments, flow rate measuringequipments, liquid and compressed air supplying equipments; The design work of thecontainer called the fluid exchange chamber which used for the preparation of theagglomeration solution has been done, for example, the size and type, the volume and so on. Besides that, a series design work of the complete system has been carried out.To explore the impact of chemical agglomeration system on the existing boilersystems and equipments, possible low-temperature corrosion, dust stratification togetherwith the fan output and the subsequent use of fly ash and other issues are included withinthe scope of consideration. The author has also put forward the improvements andprevention measures in solving the problems mentioned above. Using the bag filter systemto substitute for ESP technology, adding agglomeration system to the ESP and increasingthe electric field are compared for economic reasons, while the chemical reunion systemhas certain economic and technological advantages than a bag-type collector.