Studies On Hydrodynamics Of Straw With Coal In Three Types Of Spouted Bed And Gasification Flow Test

With the more demand for energy and the less fossil fuel,finding a new energy is to be the key mission for us today.Biomass energy as renewable energy had been paid more attention in the countries all over the world.To study,exploit and utilize the biomass energy had become an important task for all the countries in the world,too.The key question is converting biomass energy to the better status of energy if biomass will become the substitute for mineral fuels such as coal,petroleum and natural gas.Co-gasification of biomass and coal can make use of the role of combustion and gasification of coal to eliminate of tar and produce a clean high-grade heat value of gas.That not only can make a quantitative reduction of the use of coal, and the generated gas will perform an important function in the energy structural in the future.Because of the advantages of spouted bed,good heat and mass transfer performance,easy to operate and so on,there were a lot of researchers paid more attention to it in the past several decades.So it can try as a use of thermal conversion reactor.Research of spouted bed gasification system is a train of thought for new biomass gasification technology.Therefore,studies on co-gasification of biomass and coal in spouted bed has a certain theoretical and practical applications.In this paper,the mixture of Agricultural waste straw and coal was taken as raw materials for carrying out the hydrodynamic experiments in the three types spouted beds in order to provide the guiding behavior of fluid mechanics in gasification.They are necessary basic researches for comparison and development of three forms of spouted bed gasification reactor.Through continuous testing and improvement of gasification flow had been done for the development of straw and coal in the spouted bed co-gasification technology.The main task of this paper included the following several respects:(1) A conventional spouted bed had been designed with inside diameter of 400mm,height of 700mm,conical angle of 60°,gas inlet diameter of 40mm.The cold-state experimental study on straw and coal in this spouted bed was carried out: ①The relationship between pressure drop and superficial air velocity,the effects of straw content,gas inlet diameter and the height of loadings on relationship between pressure drop and superficial air velocity and relationship solid circulation rate and air flow rate were investigated.②Taking the circulating rateW,pressure drop changes of unit height materialΔP/L and the circulating rate of units effective power W/[(ΔP+P)Qs]as the criteria and selecting gas inlet diameter at 25 mm,32 mm,43 mm,the flow rate at 75 Nm³·h^-1,90 Nm³·h^-1,105 Nm³·h^-1,and the height of loadings at 200 mm,260 mm, 300 mm,and using quasi-level method to arrange Uniform Experimental Design U₁₂(12¹⁰) experiments were tested respectively.By calculating with SPSS,the regression equations were obtained.(2) A spouted bed with draft tube had been designed with inside diameter of 400mm,height of 700mm,conical angle of 60°,gas inlet diameter of 40mm,draft tube diameter of 43mm.The cold-state experimental study on straw and coal in this spouted bed was carried out:①The relationship between pressure drop and superficial air velocity,the effects of straw content,gas inlet diameter and the draft tube spouted jet distance on relationship between pressure drop and superficial air velocity and relationship solid circulation rate and air flow rate were investigated.②Taking the circulating rateW,pressure drop changes of unit height materialΔP/L and the circulating rate of units effective power W/[(ΔP+P)Qs]as the criteria and selecting gas inlet diameter at 25 mm,32 mm,43 mm,the flow rate at 55 Nm³·h^-1,73 Nm³·h^-1,92 Nm³·h^-1,and the draft tube spouted jet distance at 40 mm,60 mm,80 mm, and using quasi-level method to arrange Uniform Experimental Design U₁₂(12¹⁰) experiments were tested respectively.By calculating with SPSS,the regression equations were obtained.The results showed that:Spouted beds with draft tube not only had effective action to change the matter that spouted bed has limited capacity to deal materials, raised the height of loadings,but also greatly reduce the pressure drop,and spouted more and more stable. (3) A spouted bed with draft tube had been designed with inside diameter of 400mm,height of 700mm,conical angle of 60°,gas inlet diameter of 40mm,draft tube diameter of 43mm.The cold-state experimental study on straw and coal in this spouted bed was carried out:①The relationship between pressure drop and superficial air velocity,the effects of straw content,gas inlet diameter and the draft tube spouted jet distance on relationship between pressure drop and superficial air velocity and relationship solid circulation rate and air flow rate were investigated.②Taking the circulating rateW,pressure drop changes of unit height materialΔP/L and the circulating rate of units effective power W/[(ΔP+P)Qs]as the criteria and selecting gas inlet diameter at 25 mm,32 mm,43 mm,the flow rate at 55 Nm³·h^-1, 73 Nm³·h^-1,92 Nm³·h^-1,and the draft tube spouted jet distance at 40 mm,60 mm,80 mm,and using quasi-level method to arrange Uniform Experimental Design U₁₂(12¹⁰) experiments were tested respectively.By calculating with SPSS,the regression equations were obtained.The results showed that:Compared to the spouted bed with draft tube,the pressure drop had a slight increasing and the solids circulating velocity had a slight reducing in the spouted bed with rotating draft tube to some extent.Spouted bed with rotating draft tube could overcome the difficult in radial scale-up.(4) The biomass and coal co-gasification experiments were carried out,and with the problems encountered in the process of experiment,lots of alteration of the transformation of the spouted bed gasification system were done.All of this laid a favorable foundation for the development of large-scale thermal test.