Development And Performance Study Of Novel Micro Fluidized Beds Reactor For CO₂ Capture

CO₂ is one of the main components of indoor air pollution,which endangers human health when its concentration beyond a certain range.The removal of CO₂ from indoor air is a new and becoming an important part of indoor air purification.The central air conditioning facilities are employed for indoor ventilation in the confined rooms of modern buildings.Therefore,designing a novel reactor for CO₂ capture is of great significance for indoor air purification and the development of central air conditioning system.In this thesis,a series of novel micro fluidized beds reactors were proposed,followed by building a CO₂ capture experimental platform.Intensive investigations on the hydrodynamics behavior of gas-solids flow in the reactors were conducted based on simulation.The performance of pressure drop,CO₂ capture and adsorbent attrition in the reactors were systematically investigated by experiments.The objective of the research is to design and optimize the geometrical structure,and improve the understanding of the gas-solids flow hydrodynamics behavior in the novel micro fluidized beds reactors.The main research work is as follows:The effects of the four important parameters?the shape of the bed,the oblique angle of the bed,the inlet area of the bed and the static bed height?on the gas-solids flow characteristics in the micro fluidized bed reactors were calculated by Computational Particle-Fluid Dynamics?CPFD?modelling deeply.The micro fluidized beds with suitable shape,inlet area and static bed height were proposed to design the micro fluidized beds reactor.The effect of oblique angle of the bed on the structure of the micro fluidized beds reactor was analyzed.The simulation results of the gas-solids flow characteristics in the micro fluidized bed reactors provide a theoretical basis for the design of micro fluidized beds reactor.Two kinds of micro fluidized beds reactors were proposed and then improved by optimizing three important structure parameters,i.e.the number of the micro fluidized bed,the arrangement of the micro fluidized bed and the baffle in the micro fluidized beds reactors respectively.The Hexagonal prism Micro Fluidized Beds reactor with excellent gas-solids flow characteristics and the Square prism Micro Fluidized Beds reactor with simple and unique structure were designed.A longitudinally extended Oblique Hexagonal prism Micro Fluidized Beds reactor was proposed,which can be used in a narrow space,and exhibits lower pressure drop,better performance for CO₂ capture and lower adsorbent attrition compared with the Radial Flow Fixed Bed reactor,the Radial Adsorber and the traditional Fluidized Bed reactor.A novel Hexagonal prism Micro Fluidized Beds reactor was proposed and studied,which indicates that the micro fluidized bed in the reactor will turn to an upside-down fixed bed when the inlet velocity exceeds a certain value.The performance for CO₂ capture of the adsorbents in this reactor is better than that in the Oblique Hexagonal prism Micro Fluidized Beds reactor.A simple and unique Square prism Micro Fluidized Beds reactor was proposed to extend its application range in various spaces.The results show that better quality of the particles fluidization is achieved,pressure drop obtained from experiment is reduced by about 85%,breakthrough time is increased by nearly 35%and the adsorbent attrition is reduced by around 80%in the SMFB reactor compared with that in the FB reactor,which greatly solve the problems of high pressure drop,poor performance for CO₂ capture and serious adsorbent attrition in the reactor.The micro fluidized beds reactors proposed in this paper have the advantages of low pressure drop,better performance for CO₂ capture and low adsorbent attrition,which meet the requirements of suitable structure,high efficiency and energy saving.This research provides a significant experimental and theoretical basis for large scale CO₂ capture installed in the air conditioning system.