Research On Environment-Friendly Ground Flare System

This paper compared and analysed the advantages on performance andtechnology between smokeless low-noise environment-friendly ground flare andtraditional elevated flare, the result shows that the ground flare system isgradually becoming the first choice for petrochemical industry to process flaregas, therefore research on new environment-friendly ground flare has the vitalsignificance. The smokeless processing capacity and combustion efficiency ofthe ground burner which is the key component restricts the further widespreadapplication of the environment-friendly ground flare system. This paper outlinedthe research status and development tendency of ground burner at home andabroad, and analysed each burner’s advantages and disadvantages, then putforward the design requirements for the new burner.The main research results and contributions are as follows:(1) Design of the new burnerAccording to the design requirements of flare burner, the paper gived thestandpoint of this research, used premixed burner instead of burner withtraditional diffusion combustion structure, smokeless burning way, steam forsuppressing smoke and combustion-supporting, changed the structure ofpremixed room’s inlet in order to introduce “Coanda Effect”（“Wall-attachmentEffect”，jet fuel would have attached and followed Coanda surface in the form ofa relative thin film, thus mixture of jet fuel and air will be intensified.）, chosemultiple nozzle, added a central steam nozzle and combustion-supporting guideplate, all these laid a solid foundation for designing the new burner with highburn-off rate.(2) Numerical simulation of fluid flow process in pre-mixed roomThis paper used pre-mixed room of the new burner as physical model, setgeometric model and mesh for computational domain through CFD technology, used standard κ εturbulent model and species transport model that has nophysical and chemical reaction for two-dimensional steady numerical calculationof flare gas and air’s mixing process as well as vapour and mixture’s mixingprocess, in order to research details of fluid flow and mixing uniformity inpre-mixed room. Through the analysis of the results of numerical simulation, wecan judge whether the design of the new burner is reasonable, then reasonablyoptimize burner’s structure by changing geometric parameters such as thenozzle’s position and diameter, pre-mixed room’s length and diameter of air inlet,in order to gradually approach the expectations for the new burner designed.(3) Improvements for auto-ignition systemThis paper analysed the main components and control mechanism ofauto-ignition system, according to the control requirements and the actualsituation, it specifically realized the auto-ignition process’s control, and foundout which part of the auto-ignition facilities frequently had failures. Furthermore,this paper took some improved measures, in order to make ignition signal morecomprehensive and reliable, and to make ignition system more perfect and safer.(4) Design of the entire ground flare systemThe technological process and whole project was designed on the base ofthe main technical indicators of flare system, the selection and structure designof main devices of ground flare system was on the base of relevant standards andregulations of flare system, then the general drawing was reasonably laid out.Compared with the original diffusion-combustion ground flare system, thenew flare system’s combustion chamber and anti-radiation sound-absorbingscreen are smaller, therefore it covers smaller area, less construction investmentand costs, finally meets the design requirements.