Adsorption technology is widely used in oil vapor recovery, and adsorbents have decisive effect on separation. Three kinds of activated carbon (AC) were chosen to study their adsorption properties and adsorption energy, where n-hexane and n-heptane acted as adsorbate and adsorption experiments were conducted at 293.15 K. At the same time, regression formula of Logistic model was used to fit the throughout curves of active carbons. The results showed that: surface area and pore volume of activated carbon were the main factors affecting its adsorption properties; the adsorption behavior of n-hexane and n-heptane were corresponding to Langmuir adsorption isotherm model; adsorption energy of these three kinds of activated carbon became greater with increasing specific surface area. Fitting curve of Logistic model had high similarity with the experimental results, which could be used in the prediction of breakthrough curves of activated carbons.
Natural gas hydrate is honored as the most commercially valuable strategic resources in 21st century. It is also considered to be a highly efficient gas reservoir for its special cage crystal structure with great gas storage capacity. This provides a new way to gas storage and transportation technology. Domestic and abroad researches concerning about gas hydrate formation in surfactant were summarized. The effects of surfactant on the hydrate were analyzed. The effects of various types surfactant namely sodium dodecylsulfate(SDS), sodium dodecyl benzene sulfate(SDBS) and cetyltrimethylammonium bromide(CTAB) were analyzed. The dynamics mechanism on gas hydrate was expounded. Composite surfactants are believed to be effective on overcoming the existing inadequacy. The future research direction will include establishment of the hydrate kinetic model containing surfactant parameters.
The integrated recovery technology of condensation and adsorption was proposed,and then the recovery unit was developed.Further,the recovery effects were tested.The condensation processes of four gasoline vapor samples with different concentrations were simulated by using the sensitivity analysis tools from Aspen Plus.Considering the solar power as the energy source,the condensation temperature would be designed at-25℃,when the recovery efficiency was over 50%.The experimental results were in good agreement with the simulation results at the condensation temperature of-25℃.The vapor recovery efficiency of the integrated unit was up to 99% with the outlet vapor concentration of below 7.7g/m3,which could well meet the national emission standard.Herein,the adsorption capacity of the adsorbent was 0.24kg/kg.The saturated adsorbent could be desorbed by vacuum and further swept by nitrogen to achieve better desorption efficiency.Compared with the single adsorption process,the heat effect of the integrated process was far less,which could further improve the safety and economic benefit of the system.
Internal floating roof tank has the advantages of external floating roof tank and fixed roof tank and has its own evaporation loss properties. The influences of volatile organic compounds (VOCs) distribution gradient, molecular diffusion, thermal diffusion and forced convection on the evaporation loss of oil were studied in the space of the homemade platform of an internal floating roof tank. The results showed that thermal diffusion with temperature change was the main cause for the static loss in the internal floating roof tank. On this basis, there were some measures for reduction of the evaporation loss and formulas to calculate the evaporation loss of the internal floating roof tank in this research.
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