Theory Research And System Design Of Nitrogen Closed Loop Pneumatic Conveying

Pneumatic conveying systems are basically quite simple and are eminently suitable for the transport of powdered and granular materials in factory, site and plant situations. The system requirements are a source of compressed gas, usually air, a feed device, a conveying pipeline and a receiver to disengage the conveyed material and carrier gas. The system is totally enclosed, and if it is required, the system can operate entirely without moving parts coming into contact with the conveyed material. The text begins with pneumatic conveying theories, aims at materials which are potentially explosive, radioactive or easily oxidized researches and designs a new type of nitrogen closed loop pneumatic conveying system, with entirely closed conveying, nitrogen reclaiming, auto control etc., finally reaches the purposes of energy conservation, safety and environmental protection.At the beginning, the text introduces the excellent features and disadvantages of pneumatic conveying, summarizes the updated developed status and researched fruit of pneumatic conveying in the world, talks about the background of the thesis. goes into particulars the research contents, purposes, significance and the research methods and routes of the thesis.Based with the theory research of pneumatic conveying, deeply discusses the conveying parameters including the types of pneumatic conveying, material property, conveying air velocity, conveying pressure, the diameter of conveying pipelines and conveying pressure loss etc., aimed at the easily explosible materials in the conveying, researches and analysis the theory of nitrogen closed loop pneumatic conveying system, briefly introduces basic air equation and the motion equations of air–granule two phase flow.Based with the research theories of nitrogen closed loop pneumatic conveying system, according to the design request and design target, the thesis designs and calculates the nitrogen closed loop pneumatic conveying system, expatiates on the whole system capability and system circulation flow from two aspects of technique flow and control flow of nitrogen closed loop pneumatic conveying system, and then researches and designs the seven parts of system which are air compressor system, the nitrogen production system, the feeding and pressure conveying system, pneumatic conveying pipeline, the storage and separation system, nitrogen circulating recycle system, control system. The paper makes the selection and configuration of equipments in seven parts, and deeply discusses the capabilities and functions of these equipments in the system circulating process. The nitrogen circulating recycle system which is the keystone of the paper is researched with the design and calculation of nitrogen recycle filter device, nitrogen booster device, nitrogen pressure differential balance device, nitrogen voltage regulating and compensation device, through the research of the double-stage dust catcher, nitrogen ultra-precision filtering, speed regulating by variable frequency, parallel nitrogen feed, the system has won excellent properties of saving energy and environmental protection, and the economic benefit of nitrogen closed-loop type pneumatic conveying system is calculated and analyzed.Sulphur which is taken as the conveying material of nitrogen closed loop pneumatic conveying system is conveyed in the experiments, according to the located layout and circulated status, gets the ideal experiment results. checks out the characters of energy saving and environmental protection and the reliability and stability of nitrogen closed loop pneumatic conveying system.In the end, summarizes the main research contents of the thesis, puts forward the prospect of persistently spreading and applying in the future and improvement and perfect in aspects of energy conservation and environmental protection career.