| At present,expanded graphite has become the main material for emergency and efficient treatment of marine oil spills due to its high efficiency of oil absorption.The use of pipeline pneumatic conveying has realized the transportation of expanded graphite materials between various process equipment.However,due to the particularity of expanded graphite,ultra-light materials,in the pipeline layout design and the setting of pneumatic conveying parameters,there is still a lack of data reference and experience with targeted design,which leads to the expansion of graphite materials in the process of transportation.It is common for materials to be intermittently unevenly distributed,severely crushed by particles,and even blockage of materials.Therefore,it is necessary to carry out research on the characteristics of pneumatic conveying of expanded graphite ultra-light materials,develop a new pneumatic conveying scheme,and provide theoretical and technical support for the continuous and stable transportation of expanded graphite ultra-light materials.Firstly,the transportation mechanism and force of the material particles are analyzed,and the selection of the mechanical model in the CFD-EDEM coupling model is determined.At the same time,the influencing factors of the expansion of expanded graphite ultra-light materials were theoretically analyzed,and the parameters of the conveying pipeline were designed and determined.Based on the single gas source pipeline transportation scheme at the end of the pneumatic system,a new multi-gas source pneumatic conveying scheme is proposed in which the jet-elements are arranged in the pipeline.Then,a single gas source expanded graphite pneumatic conveying experimental platform was built and the experiment was carried out.The steady conveying speed of the conveying wind was obtained through experiments.At the same time,it analyzes the existence of large pipeline pressure drop and flow stability.In order to optimize the conveying characteristics,it is proposed to arrange the jet-elements in the pipeline to form a multi-gas source pneumatic conveying system.Then,according to the jet-attachment effect,the jet-element is designed and its structure is optimized.The CFD numerical simulation calculation of the different positions of the jet-elements in the pipeline is carried out,and a reasonable arrangement of the jet-elements in the pipeline is obtained.A distribution valve in the air supply system is designed to achieve pulsating and continuous input airflow distribution.Finally,the CFD-EDEM gas-solid two-phase flow coupling numerical calculation method is applied to simulate the multi-gas source transportation scheme,and the pipeline layout schemes of different jet components are analyzed,and the relevant parameter changes are analyzed under different combinations of conveying wind speed levels.The influence of the flow of material particles determines the ideal solution and delivery parameters.This paper analyzes the pipeline characteristics of single gas source expanded graphite,and proposes a multi-gas source transportation scheme for arranging jet-elements in pipelines,which has important theoretical and technical reference value for the development of new schemes for expanded graphite pneumatic conveying. |
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