| In the process of light petroleum products (such as gasoline) loading, unloading, storage, transportation, or distribution, a great deal of the petroleum vapor are evaporated and emitted from the tanks/tankers to air and will bring on serious petroleum loss and harm to the users. Petroleum products evaporation loss (PPEL) is a much important research topic for petroleum and environmental protection scientists and engineers. The rule of PPEL was investigated and the control methods and systems of the emitted vapor were developed. The results and achievements are summarized as follows:(1) Base on molecule diffusion and mass transfer theory, a mathematic model on the unsteady petroleum evaporation and discharge process was established, and some formulae were educed to appraise the evaporation and discharge rule and calculate the vapor concentration, the evaporation volumes, losses, and so on. Some key parameters such as gasoline vapor mole quality and compression factor, vapor pressure, and vapor-air diffusion coefficient were decided and recommended. A lab-sized test and evaluation system of gasoline evaporation loss in gasoline loading tank was built up with reference to field operation. Some key effect factors on the vented vapor concentration and the evaporation lossage, such as the height of the exit of filling gasoline pipeline to tank bottom, initial vapor concentration in the tank gas space, speed of filling gasoline, and temperature of the system, were investigated and measured and appraised. The results showed they influence notably on the concentration and the lossage respectively, and more by them interacting.(2) As one of the effective measures to control PPEL, the technique of activated carbon (AC) adsorption recovery the vapor was investigated and developed. A lab-scale test and evaluation system of AC adsorption recovery gasoline vapor was built up, and the adsorption kinetics and thermodynamics was analyzed and appraised. The result showed that fresh AC adsorptivity to gasoline vapor is up to 0.34 at 20℃ and to 0.30 at 30℃. The adsorptivity decreases with the rise in adsorption operation temperature and in circulation times. The differential pressure of adsorption bed is low and the average value is about 0.142Pa cm-1. The result also showed that AC adsorption heat to gasoline vapor is obviously high and the temperature of adsorption bed is about from 20℃ up to 70~78℃ at the inlet vapor volume fraction of 0.30?.03, and the adsorption is taken near as an adiabatic operation owing to low AC heat transfer coefficient of 0.145~0.203wm-1.℃-1. The adsorption heat causes reduction of AC adsorptivity and may also bring about ACchemical adsorption to gasoline vapor and then destroy the tiny hole structure and useful surface of AC and shorten AC service life-span, and further, bring about AC bed hidden fire accident. A mathematic model on differential temperature of adsorption bed was established to appraise and estimate the adsorption heat effect, and the calculation result showed the adsorption heat will increase quickly with a rise in the inlet vapor concentration, so the technique and unit of AC adsorption recovery the vapor was recommended to take action with other recovery unit and to play later-stage further recovery role in order to make vapor concentration in the tail gas mixtures to reach hydrocarbon exhaust index. Last, the desorption of rich AC was recommended by high vacuum system, and it's effective while desorption pressure is about 625 ~ 2625Pa (absolute).(3) As one of the more effective measures to reduce PPEL, the technique and apparatus of absorption recovery the vapor by the right absorbent was systematically investigated and developed. It was the first step to sift out the right absorbent from some typical absorbents by theoretical analysis and comprehensive test survey in a series of lab-scale test and evaluation systems including self-designed orthogonalization absorption experiment, and then the absorbent ABS-2 was developed and recommended to use. Secondly, a mid-scale t... |
PDF Full Text Request