Open storage yards at industrial sites usually comprise several piles of granular materials, representing a particulate matter source that may significantly deteriorate air quality. With the increase in particle diameter, the dust concentration distribution presents the trend of interior hollowing and high-concentration area fragmenting. Under the same starting speed, the dispersion distance of dust decreases with the increase in particle diameter. The increase in particle diameter increases the kinetic energy loss of particles for the fluid. Results show that a high-concentration range of the dust exists near the pile behind the wind direction and may continue to spread to the height due to the influence of a whirlpool, and the dispersion distance and width can increase with the increase in wind speed. Although a large gap exists between the assumption and the real atmospheric environment, this study provides a reference for the evaluation of the pollution scope of blowing dust and prevention and control of pollution. The complex atmospheric environment is simplified as unidirectional wind, and the influence of different wind speeds on the dispersion of particles with diverse sizes in the pile is studied. The dispersion characteristics of dust particles around the pile under the action of unidirectional wind are studied through wind tunnel test and numerical simulation. In this study, a pile of sodium carbonate in a large open-air pile in Weifang, China, is regarded as the research object. Studying the law of dust diffusion in local areas is of great significance for the atmospheric particulate control. To maintain the dust emissions at an acceptably low level, other measures such as spraying with water and crust-forming liquids may still be necessary at higher wind velocities.Ī large amount of dust particles produced by the wind in an open-air pile is one of the important reasons for air pollution. The angle of incoming wind is a key factor influencing effectiveness of both solid and porous windbarriers The proposed placement of porous barriers between the piles has shown to be effective in reducing wind exposure and dust emission. Realistic stockpile geometry with adjacent structures has shown to cause wind velocity distributions, which are not consistent with the most studied cases of regular pile shapes and layouts. On the other hand, pile rearrangement has little effect and may not be practical for implementation.
Comparison of selected cases shows a positive, although limited effect of porous fences and barriers on reduction of local velocities and consequently dust erosion rate. Results from numerical modelling were used in the USEPA model to determine dust emission factors. Wind velocity fields above the piles were calculated for the current stockpile layout and for several modified cases with rearranged piles and added porous barriers. Dust lifting presents a serious environment and health hazard, thus the main objective of our study was to propose efficient measures for wind erosion reduction A numerical model of the stockpile was created using the computational fluid dynamics (CFD) software. What is the GsbSSD of the blended aggregate? If you need 30 tons of the blended aggregate in the SSD condition, how much do you need to take from each stockpile? Stockpile A Stockpile B GsbSSD % abs % total water 2.630 0.9 1.9 2.554 1.4 1.This paper investigates the dust lifting phenomenon at the coal and iron ore stockpile at the Port of Koper, Slovenia. You are going to make PCC with a blend of 60% stockpile A and 40% stockpile B (the blend percentages assume the stockpiles are in the SSD condition).
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If the total weight of the stockpile is 20 tons, how much free water (in tons) is in the stockpile? If you want 5 tons of aggregate in the SSD condition, how much (in tons) aggregate do you need to take from the stockpile and how much water you will need to add or remove from that aggregate to get it to SSD condition? 3. An aggregate stockpile has a % abs-1.5% and the total moisture content in the stockpile is 1.1%. What proportion of each aggregate stockpile do you need? 2. You want to mix the two stockpiles to get a blend that has a Gsb-2.675. You have a coarse aggregate stockpile with a Gsb-2.723 and a fine aggregate stockpile with a Gsb-2.611.
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