Polymer-coated silica nanoparticles (PSiNPs) have been experimentally investigated in core- and micro-scale studies for enhanced oil recovery (EOR). Wettability and flow rate have a considerable effect on oil displacement in porous media. This work investigates the efficiency of PSiNPs for oil recovery on micro-scale at three wettability states (water-wet, intermediate-wet, and oil-wet). In addition, a cluster mobilization regime is considered in all experiments. A microfluidic approach was utilized to perform flooding experiments with constant experimental settings such as flowrate, pore-structure, initial oil topology, porosity, and permeability. In this study, the wettability of the microfluidic chips was altered to have three states of wettability. Firstly, a micro-scale study (brine-oil-glass system) of each wettability condition effect on flow behavior was conducted via monitoring dynamic changes in the oleic phase. Secondly, the obtained results were used as a basis to understand the changes induced by the PSiNPs while flooding at the same conditions. The experimental data were extracted by means of image processing and analysis at a high spatial and temporal resolution. Low injection rate experiments (corresponding to ~1.26 m/day in reservoir) in a brine-oil-glass system showed that the waterflood invaded with a more stable front with a slower displacement velocity in the water-wet state compared to the other states, which had water channeling through the big pores. As a result, a faster stop of the dynamic changes for the intermediate- and oil-wet state was observed, leading to lower oil recoveries compared to the water-wet state. In a cluster mobilization regime, dynamic changes were noticeable only for the oil-wet condition. For the aforementioned different conditions, PSiNPs improved oil displacement efficiency. The usage of PSiNPs showed a better clusterization efficiency, leading to a higher mobilization, smaller remaining oil clusters, and lower connectivity of the residual oil. The knowledge from this experimental work adds to the understanding of the behavior of polymer-coated silica nanoparticles as a recovery agent at different wettability states and a cluster mobilization regime.
A grain size reduction hammer mill for crushing corn (Zea mays L.) was designed depending on variety characteristics and by using computer aided design "ANSYS" software. Suitability of fabricated hammer was tested at three levels of hammer rotor speeds (RS) (600, 1000 and 1440 rpm), three levels of screen holes diameter (Sd) (2, 4 and 6 mm) and three levels of feeding rates (FR) (60, 90 and 120 kg h-1). Geometric mean diameter of crushed corn (dgw), machine productivity (Pm), consumed energy (CE) and cost (CO) were evaluation criteria. Results indicated that the highest (Pm) (113 kg h-1) and lowest (CE and CO) were at 1440 rpm (RS), 6 mm (Sd) and 120 kg h-1 (FR). The empirical results obtained from experiments were used to introduce a derived mathematical equation to predict the value of "dgw, Pm, CE and CO" as a function of "RS, FR and Sd".
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