(3em) Effect of Wettability on Dissolved Gas Liberation, Boiling and Enhanced Oil Recovery

Research Interests: Surface Science; Microfluidics; Bubble Nucleation; Enhanced Oil Recovery (EOR); Polymer Technology; Material Science.

Teaching Interests: Process Simulation (Aspen Plus); Refinery Engineering; Reservoir Engineering.

Research conducted during doctoral studies:

Principal Investigator: Dr. Prem Bikkina

1. Preparation and quantification of surfaces of different wettabilities

Wettability, which is a surface or material property that defines its relative affinity towards a fluid in the existence of another immiscible or sparingly soluble fluid. The surfaces of various wettabilities have various applications in petroleum engineering, nucleation studies, nucleate boiling, etc. Our study aims at developing experimental techniques to prepare solid surfaces of various wettabilities (i.e. super hydrophilic, intermediate-wet and hydrophobic). The surfaces prepared are successfully implemented in studying the effect of wettability on pressure-, vacuum- and temperature- driven nucleation.

2. Study the effect of wettability on bubble nucleation

Dissolved gas liberation from a liquid arises either by diffusion over the gas-liquid interface and/or by nucleation occur at the solid-liquid interface. Our research aims at studying the effect of pressure and wettability on bubble nucleation using wide solubility range of gases like carbon dioxide, methane and nitrogen in water. Based on the results, it was concluded that wettability of the solid surface has strong correlation on the onset pressure for bubble nucleation. It was observed that as the hydrophobicity increases, required supersaturation for bubble nucleation decreases and hence, the onset pressure for bubble nucleation increases. Further experimental findings revealed that their exists an effect of step-down pressure and wettability on sparingly soluble gas bubble nucleation, i.e. sparingly soluble gases can only be nucleated at a certain level of step-down pressure. Similar studies were conduct to examine the influence of sub-atmospheric pressure on bubble nucleation on different hydrophobic surfaces. This study revealed that hydrophobicity of the solid surface has a strong influence on the onset vacuum level for vapor bubble nucleation, and vacuum boiling. The benefits of this method include purification of water by removing the dissolved gases and salts. Moreover, the production of drinkable water from produced water via vacuum boiling can be achieved with a significantly lower energy input. Later our research focused in studying the effect of wettability on nucleate boiling. This research indicated that the nucleate boiling can be spatially controlled by controlling the wetting nature of heating and boiling surfaces.

3. Microfluidics based enhanced oil recovery (EOR) study

An in-depth understanding of oil recovery mechanisms in complex pore networks is critical for the estimation of recovery factors in oil reservoirs. In this study, we have performed systematic microfluidics experiments to evaluate the oil recovery performances of waterflooding, gas flooding, and huff-n-puff processes in both hydrophilic and hydrophobic microfluidic chips of different aspect ratios. Key findings of this study showed that oil saturation increases semi-logarithmically with aspect ratio for both hydrophilic and hydrophobic micromodels. Moreover, during the ‘Huff-n-Puff’ process, up to 20 % PV (pore volume) oil was produced in hydrophilic chips, whereas less than 5 % PV of oil was produced in hydrophobic chips. The results obtained from the study would be useful to validate flow simulation models in digital rock examination.

Research conducted during master’s degree:

Principal Investigator: Prof. V.S. Moholkar

1. Production of bio-polymer Polyhydroxybutyrate (PHB) by ultrasound-assisted extraction

Biodegradable polymer is one of the promising alternatives for petroleum derived polymers. This study was focused to develop a novel method for the synthesis of bio-polymer poly(3–hydroxybutyrate) (PHB) using two microorganisms, viz. Bacillus megaterium and Cupriavidus necator by ultrasound-assisted extraction. The important results ascertained that the synthesized PHB (under ultrasound assisted extraction) has greater resistance to thermal degradation as compared to standard or commercial PHB. Moreover, the synthesis of PHB via ultrasound-assisted route can significantly reduce the cost of fermentation process and simultaneously lessen the hazardous effect to environment and human health with a high potential of commercialization. This study was further extended to synthesize PHB polymer from two ubiquitous invasive weeds, viz. P. hysterophorus and E. crassipes. The characterization of PHB revealed significant differences in thermal properties of pentose- and hexose-derived PHBs. PHB from pentose-rich hydrolyzate had higher glass transition temperature while PHB from hexose-rich hydrolyzate had higher maximum thermal degradation temperature. This study puts forth a feasible solution for controlling the spread of the invasive weed, and an effective way of utilizing it for purpose of biofuels production. This process has high potential for commercialization.

References:

1. Pradhan, R.J. Qader, B. Sedai, P. Bikkina; Influence of Wettability on Pressure-Driven Bubble Nucleation: A Potential Method for Dissolved Gas Separation, Vol. 217, pp.31-39, Separation and Purification Technology (2019)
2. Pradhan, A. J. Borah, M. K. Poddar, P. K. Dikshit, L. Rohidas, V.S. Moholkar; Microbial Production, Ultrasound-Assisted Extraction and Characterization of Biopolymer Polyhydroxybutyrate (PHB) from Terrestrial (P. hysterophorus) and Aquatic (E. crassipes) Invasive Weeds, Bioresource Technology, Vol. 242, pp.304-310 (2017)
3. K. Poddar, S. Pradhan, V.S. Moholkar, M. Arjamand, U. Sundararaj; Ultrasound–Assisted Synthesis and Characterization of Polymethyl Methacrylate/Reduced Graphene Oxide Nanocomposites, Vol. 64, Issue 2, pp.673-687, AIChE Journal (2018)
4. Pradhan, P. K. Dikshit, V.S. Moholkar; Production, Ultrasonic Extraction, and Characterization of Polyhydroxybutyrate (PHB) using Bacillus megaterium and Ralstonia eutropha as Potential Micro-organism, Vol. 29, Issue 8, pp.2392-2400, Polymers for Advanced Technologies (2018)
5. Bikkina, S. Pradhan; A Potential Solution for Boiling Crisis, Proceedings of 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH), Portland, Oregon, USA, Vol. 2328, pp.1383-1396, Paper ID: 27915 (2019)
6. Pradhan, P.K. Dikshit, V.S. Moholkar; Chapter Title: Production, Characterization and Applications of Biodegradable Polymer: Polyhydroxyalkanoates, pp.51-94; In Book: Advances in Sustainable Polymers: Synthesis, Fabrication and Characterization