Storage and Transportation Technology: 【Question of the Day】10-11-19 [Friday]
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This post was last edited by flute6 on 2010-12-7 00:33. Multiple-choice question: 1. Large breathing losses are caused by ( ). A: Oil transfer B: Temperature difference C: Sunlight exposure D: Heating Note: 1) Participants will be rewarded; more explanations are encouraged. 2) Please hide your replies; the method to do this is: http://bbs.hcbbs.com/thread-492556-1-1.html. Do not edit the replies after posting them. 3) The answer will be visible immediately after responding. Answer released: Answer: A. When fuel is dispensed from a tank, the drop in liquid level allows air to be drawn in, which reduces the vapor pressure of the fuel and promotes its evaporation. When the storage tank is receiving oil, as the liquid level in the tank rises, the oil vapor is expelled from the tank. The resulting loss of oil and gas is known as “big breath” loss. When the oil is at rest in the storage tank, oil vapor fills the vapor space within the tank. Changes in the ambient temperature or the oil temperature cause the oil vapor to expand when heated and contract when cooled, resulting in the oil vapor overflowing from the tank. This type of loss is called “shallow breathing” loss.
Reply 1# flute6 d
1. A Evaporation losses can generally be divided into three types: natural ventilation losses, “small breathing” losses, and “large breathing” losses. Natural ventilation losses occur due to the impermeability of the oil storage container; holes in the tank roof or a difference in height between those holes, combined with the fact that the density of the gas mixture inside the tank is greater than that of the outside air, lead to gas convection and thus losses. The external temperature and pressure constantly change throughout the day depending on the weather conditions, and as a result, the pressure and temperature of the mixture inside the tank also change. The process by which the mixture inside the tank and the air outside it are exchanged through the tank’s breather valve is known as \"minor breathing\" loss. The “deep breathing” loss refers to the process in which changes in the oil level during loading and unloading operations of oil tanks cause changes in the internal gas space, resulting in the expulsion of mixed oil and gas or the intake of external air. “\"Small breath\" losses and \"large breath\" losses are also commonly referred to as static storage losses in oil tanks and dynamic losses in oil tanks.
Large breathing losses are caused by (A) oil transfer. * }0 b: C: x- x" o