Enhancement Of Foam Stability Research Articles

Impact of Hydrocolloids and Homogenization Treatment on the Foaming Properties of Raspberry Fruit Puree

The production of healthy, ready-to-eat fruit snacks by means of foam-mat drying has to face the challenge of ensuring high foam stability throughout the entire process. Foaming properties of raspberry puree whipped for 10 min with varying concentrations of potato protein isolate (2.5, 5, 10% w/w) as foaming agent were studied. Furthermore, the impact of hydrocolloids as foam stabilizers, i.e., maltodextrin (5, 15, 30% w/w) and pectin (0.1, 0.25, 0.5, 0.75, 1.0, 2.5% w/w), in combination with the variation of protein concentration as well as the impact of a homogenization treatment of fruit puree on the foam characteristics and puree properties were investigated. Foam stability was enhanced by the increase of protein and hydrocolloid concentration. Maltodextrin and pectin showed similar behavior even though pectin was used at considerably smaller concentrations. Compared to single hydrocolloid systems, the addition of pectin and maltodextrin in combination led to a further enhancement of foam stability, which offered the opportunity to simultaneously decrease the concentration of both hydrocolloids. The destruction of fruit tissue by homogenization treatment resulted in a reduction of mean particle diameters (D[4,3], D[3,2]) and a decrease of viscosity. Despite the increase in the specific surface area (ASF) and thus, expected enhanced oxidative processes, no changes were observed for ascorbic acid and anthocyanin contents. However, the structural changes induced by the homogenization treatment significantly affected foaming properties.

Experimental and numerical investigation into nano-stabilized foams in low permeability reservoir hydraulic fracturing applications

Hydraulic fracturing is one of the most effective and efficient methods to enhance oil and gas recovery from reservoirs. Well productivity is mainly determined by the propped dimensions of the fracture. However, the propped dimensions are controlled by proppant transport and proppant placement, of which settling and convection are the controlling mechanisms. In this paper, a new concept is described to overcome the problem of proppant settling during a foam fracturing treatment and prior to fracture closure. This new concept consists of introducing nanoparticles into the base fracturing fluid system to stabilize the foam structure and reduce proppant settling. The results show that foam stability directly influences proppant placement and final fracture conductivity. When foam fracturing fluids experience long closure times, most often as a result of low leakoff, foam breakage occurs. This breakage results in proppant settling and accumulation at the bottom of the fracture, reducing propped dimensions. Whilst, high pumping rates and foam quality provide greater initial propped area, foam stability is major factor controlling the final propped area and productivity. Experimental results show that foam stability increases 2–3-fold in presence of 0.8-wt% silica nanoparticles under 90 °C. The enhancement of foam stability using nanoparticles, particularly foam life-time, allows better proppant suspension, maintains post-fracture conductivity, and minimizes productivity losses. This work is intended to guide the practitioner in the use of nano-stabilized foam to improve unconventional reservoir stimulation.

Effects of Nanoparticle Types on Carbon Dioxide Foam Flooding in Enhanced Oil Recovery

Enhancement of foam stability has been recently evidenced with addition of nanoparticles (NPs), especially in the case of CO2 foams. Stabilized foams via solid NPs can potentially withstand high reservoirs temperatures. Studies have been conducted to examine the effect of NPs on foam stability; however, more research is required for various types of NPs. Therefore, the authors aimed to investigate the performance of silicon dioxide (SiO2), aluminum oxide (Al2O3), copper oxide (CuO), and titanium dioxide (TiO2) of different sizes in the presence of fixed concentration of anionic surfactant (AOS) on foam stability. Nano particle concentrations of (0.1 wt%, 0.3 wt%, 0.5 wt%, and 1 wt%) were used to investigate the foam stability, displacement test were performed to determine oil recovery at the optimum concentrations for each nanoparticle. The stability of the aqueous foam was evaluated by the Ross-Miles method using half-life measurements. All experiments were conducted at room temperature and pressure. The results revealed that all different NPs used were able to improve the stability of CO2 foam at certain concentrations. However, aluminum oxide NPs showed better results compared to others in terms of foam stability and half-life time. In addition, 0.1 wt% of all NPs types gave the highest foam stability and half-life time. In conclusion, a low concentration of NPs is recommended regardless of type for improving form stability.