Study On Microwave Heating Activated Carbons Loaded With SO₂ And Carbon-thermal Reduction Of SO₂

Flue Gas Desulfurization?FGD?by activated carbon is efficient and various pollutants can be removed at the same time.The process not only consumes less water,but also can recycle sulfur resource.FGD is a promising technology.But because of the high energy comsumption,high cost and the increasing scarce production resources,it inevitably cause resource waste and secondary pollution if the activated carbon is discarded.It greatly limits the scope of application of activated carbon.Microwave-heating method is a new technology.It can not only heat more uniformly,more rapidly,selectively,but also it can get higher rate of regeneration.At present,the activated carbon regeneration and SO₂ reduction technology has drawn the attention of scholars.But the microwave regeneration of activated carbon loaded with SO₂ and the heating characteristic of activated carbon in microwave oven are lack of theoretical basis.Currently,the majority of research focus on the SO₂ reduction by conventional-heating method and the research of SO₂ reduction by microwave-heating is very few.This dissertation will study the heating characteristic of activated carbon in microwave oven by the software of COMSOL Multiphysics which is based on finite element analysis.Meanwhile,this dissertation also study the effects of different kinds of carbon materials on SO₂ reduction by carbon-thermal.And compare the conventional-heating method and the microwave-heating method.Finally,based on the above analysis and summary,we design and build a pilotscale experimental system which put the microwave-regeneration of SO₂ and SO₂ reduction togerher.This pilotscale experimental provides data base for industrial applications of FGD by activated carbon.In this paper,firstly,the heating characteristic of activated carbon in the microwave oven was simulated by the software of COMSOL Multiphysics which is based on finite element analysis.The results showed that the temperature of actived carbon in microwave field rise fast.The higher microwave power,the faster heating rate,and the higher final temperature of actived carbon.The waveguide position has a great influence on the heating characteristics of the actived carbon in the microwave field.When the two waveguides act on the same microwave field,the two waveguides will interfere with each other.So that the heating characteristic of the actived carbon in the microwave field is deteriorated and the strength of interference between the two waveguides is determinded by the relative position of the two waveguides.The physical properties of the actived carbon have a great influence on the heating characteristic of active carbon in the microwave field.With the increase of the relative permittivity and the thermal conductivity of the actived carbon,the final temperature of the actived carbon increases in the microwave field.At the same time,the radius of the actived carbon,the position of the actived carbon and the size of the microwave cavity also have a great influence on the heating characteristic in the microwave field.Secondly,the mechanism of carbothermal reduction of SO₂ as element sulfur was studied.Considering the SO₂ conversion and S yield,it was found that the coconut-shell AC is the best.By comparing the conventional-heating method and the microwave-heating method,it was found that,at the same reaction temperature,the SO₂ conversion and the S yield in microwave-heating method are higher.Finally,with the above simulation and mechanism research,the design and experiment of the microwave regeneration and SO₂ reduction in the 1MW pilotscale experiment on combined desulfurization and denitrification were carried out.It was found that with the increase of microwave power,the better effect of coke regeneration.And according to the problems found in the experiment,we transform the test system and develop the next experimental plan.