An experimental study on oil droplet size distribution in subsurface oil releases

Oil droplet size distribution （ODSD） plays a critical role in the rising velocity and transport of oil droplets in subsurface oil releases. In this paper, subsurface oil release experiments were conducted to study ODSD under different experimental conditions in a laboratory water tank observed by two high-speed cameras in March and April 2017. The correlation formulas Oh=lO.2Re-~ and Oh=39.2Re-1 （Re represents Reynolds number and Oh represents Ohnesorge number） were established to distinguish the boundaries of the three instability regimes in dimensionless space based on the experimental results. The oil droplet sizes from the experimental data showed an excellent match to the Rosin-Rammler distribution function with determination coefficients ranging from 0.86 to 1.00 for Lvda 10-1 oil. This paper also explored the influence factors on and change rules ofoil droplet size. The volume median diameter d50 decreased steadily with increasing jet velocity, and a sharp decrease occurred in the laminar-breakup regime. At Weber numbers （We） 〈100, the orifice diameter and oil viscosity appeared to have a large influence on the mean droplet diameter. At 100〈We〈1 000, the oil viscosity appeared to have a larger influence on the relative mean droplet diameter.

The Influence of Poly(Vinyl Alcohol)on Oil Release Behavior of Polylactide-Based Composites Filled with Linseed Cake

In order to limit the negative impact of industry on natural environment,ecological alternatives to conventional polymers are being proposed.One of the most popular“green”polymers is polylactide,which can also be successfully applied as a matrix of composites.The application of ground linseed cake as a filler for polylactide-based composites is in line with the idea of Circular Economy,and moreover it provides a modifying effect on the polymer by increasing its crystallinity and reducing its brittleness.This effect is caused by the presence of linseed oil which can be released to the polymeric matrix in a non-controlled way.In order to control the miscibility of the oil and the polymer,we modified the filler particles with poly(vinyl alcohol)before introducing it to the polylactide.We concluded that poly(vinyl alcohol),which does not mix with oil,encapsulated the active ingredients inside the filler particles.We evaluated the mechanical properties of the composites containing 5,10,20 and 30 wt%of the filler in a static tensile stress and by means of dynamic mechanical thermal analysis.Crystallinity and thermal properties were tested using differential scanning calorimetry as well as thermogravimetric analysis.Composites’microstructure was evaluated by Scanning Electron Microscopy.It was found that modifying the oil-rich filler with poly(vinyl alcohol)helps to reduce its release to the matrix and thus limits the plasticizing effect of linseed cake.This result was in accordance with our hypothesis.

Tuning thermal release kinetics of soy oil from organic nanoparticles using variable synthesis conditions

The thermal release properties of soy oil from poly（styrene-co-maleimide） nanoparticles containing 50 wt% encapsulated oil have been quantified as a function of temperature and time. The effects of dif- ferent synthesis conditions on the thermal stability of the nanoparticles and their oil release have been evaluated, i.e., by gradually increasing the amount of ammonium hydroxide used for the imidization of poly（styrene-co-maleic anhydride）. First, the intrinsic thermal properties of the oil-filled nanoparti- cles were analysed by differential scanning calorimetry, which revealed an exothermal reaction related to the oil release and a suppression of the glass transition that may be masked owing to the complex structure of the hybrid nanoparticles. The isothermal scans showed different rates of oil release after a post-imidization reaction. The oil release was better followed by dynamic mechanical analysis, which illustrated changes in visco-elastic properties expressed by the maximum in the loss factor that related to the amount of released oil. Depending on the amount of ammonium hydroxide, the oil started to release below the glass transition temperature at various rates. Thermal release profiles of the oil we re quantified by infrared and Raman spectrocopy after heating for 2 min to 6 h at 125 to 250 ℃, based on variations in oil-related and imide-related absorption bands. The oil release increased below and above the glass transition temperature, following a parabolic trend, and progressively decreased at higher ammonium hydroxide concentrations, in parallel with higher imide content and changes in imide conformation. The kinetics and mechanism of the oil release can be described by the Korsmeyer-Peppas model, suggesting a dominating diffusion mechanism that is influenced by further imidization of the polymer matrix during heating.

A Study of Fluid Flow in Sediments and the Effect of Tidal Pumping

Offshore drilling and production operations can result in spills or leaks of hydrocarbons into seabed sediments, which can potentially contaminate these sediments with oil. If this oil later mi- grates to the water surface it has the potential for negative environmental impacts. For proper contin- gency planning and to avoid larger consequences in the environment, it is essential to understand me- chanisms and rates for hydrocarbon migration from oil containing sediments to the water surface as well as how much will remain trapped in the sediments. It is believed that the amount of oil transported out of the sediment can be affected by tidal pumping, a common form of subterranean groundwater dis- charge （SGD）. However, we could find no study experimentally investigating the phenomenon of fluid flow in subsea sediments containing oil and the effects of tidal pumping. This study presents an experi- mental investigation of tidal pumping to determine if it is a possible mechanism that may contribute to the appearance of an oil sheen on the ocean surface above a sediment bed containing oil. An experimen- tal apparatus was constructed of clear PVC pipe allowing for oil migration to be monitored as it flowed out of a sand pack containing oil, while tidal pressure oscillations were applied in three different man- ners. The effect of tidal pumping was simulated via compression of air above the water （which simulated the increasing static head from tidal exchange）. Experimental results show that sustained oil release oc- curred from all tests, and tests with oscillating pressure produced for longer periods of time. Further- more, the experimental results showed that the oil migration rate was affected by grain size, oil satura- tion, and oscillation wave type. In all oscillating experiments the rate and ultimate recovery was less than the comparable static experiments. For the conditions studied, the experimental results indicate that with an oscillating pressure on top of a sand pack, movement of a non-replenishing source of oil is sup- pressed by pressure oscillation.

Composite microcapsules with enhanced mechanical stability and reduced active ingredient leakage

A calcium shellac （CS） matrix was used to encapsulate polymeric melamine formaldehyde microcapsules （A） or CaCO3 nanoparticles-stabilized microcapsules （B）, both of which encapsulated an oil-based active ingredient, producing A-CS or B-CS composite microcapsules. The mechanical properties and oil release profiles of the composite microcapsules were evaluated. The composite microcapsules showed enhanced mechanical stability and reduced leakage of the active ingredient hv one order of magnitude.