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Experimental measurements and predictions for dissociation conditions of carbon dioxide hydrates in the presence of 0.05, 0.10, 0.15, and 0.20 mass fractions triethylene glycol aqueous solutions and methane hydrates in the presence of 0.245, 0.40, and 0.50 mass fractions triethylene glycol aqueous solutions are reported in this work. The data have been measured in temperature ranges of (264.7 to 282.6) K for carbon dioxide hydrates and (264.8 to 275.8) K for methane hydrates in the presence of triethylene glycol aqueous solutions. The experimental data have been measured using a reliable isochoric technique. A general correlation has been used for predicting hydrate dissociation conditions. Acceptable agreement has been achieved between experimental and predicted data with a maximum of 0.5 K deviations.

Experimental dissociation data for ethane and propane simple hydrates in the presence of (0.05 and 0.15) mass fractions of methanol, ethylene glycol, and triethylene glycol aqueous solutions are reported in this work. The experimental data have been measured using an isochoric method. All the experimental data are compared with the predictions of a general correlation (HWHYD correlation) and a thermodynamic model (HWHYD model). The agreements between the experimental and predicted data are generally found acceptable.

Experimental gas hydrate dissociation data for ethane + distilled water, propane + distilled water, methane + 0.05 and 0.1 mass fraction ethanol aqueous solution, ethane + 0.05 and 0.1 mass fraction ethanol aqueous solution, propane + 0.05 and 0.1 mass fraction ethanol aqueous solution, and carbon dioxide + 0.05 and 0.1 mass fraction ethanol aqueous solution systems are reported herein. The new experimental data have been measured using an isochoric method. All the experimental data are compared with the predictions of a general correlation and a thermodynamic model. The agreements between the experimental and predicted data are generally found to be acceptable. The hydrate dissociation data for ethane + distilled water and propane + distilled water systems are also compared with some experimental data reported in the literature, and acceptable agreements between the data indicate the reliability of the experimental technique used in this study.

Experimental solubilities are reported for methane, ethane, ethylene, propane, and propylene in trihexyl tetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate [P(14)666][TMPP] from 313 to 353 K up to 6.7 MPa. A literature review on solubilities of small hydrocarbons in ionic liquids shows that solubilities in [P(14)666][TMPP] are appreciably larger than those in other ionic liquids. Contrary to solubilities in ionic liquids studied earlier, solubilities of paraffins (ethane and propane) in [P(14)666][TMPP] are larger than those of the corresponding olefins (ethylene and propylene). Because, at fixed temperature, the vapor pressure of an olefin is larger than that of the corresponding paraffin, the relative volatility of the olefin exceeds that of the corresponding paraffin, contrary to the relative volatility observed in conventional extractive distillation with polar solvents where the volatility of the paraffin exceeds that of the corresponding olefin.

Experimental solubilities are reported for methane, ethane, ethylene, and propane in ionic liquid tetrabutylphosphonium bis(2,4,4-trimethylpentyl) phosphinate [P4444][TMPP] from 313 K to 353 K up to 5 MPa. [P4444] [TMPP] shows solubilities for methane, ethane, ethylene, and propane that are appreciably larger than those in other typical ionic liquids. However, unlike a hydrocarbon solvent, [P4444][TMPP] is not flammable at ordinary conditions. Unlike other typical ionic liquids, the solubility for ethane is larger than that for ethylene. Because the viscosity of [P4444][TMPP] is high, we consider a low-viscosity diluent. Therefore, experimental solubilities are also reported for the same solutes in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [EMIM][Tf2N] from 299 K to 354 K up to 4 MPa. Comparison between our results and literature data shows good agreement.

Future energy security and environmental issues are major driving forces for increased biomass utilization globally and especially in developing countries like Pakistan. For efficient utilization of indigenous biomass resources in the future energy mix, it is important to gain knowledge of current energy system in various sectors. Some of the technologies and initiatives are under development to achieve transition from non-renewable resources to renewable resources, and reducing fossil fuel dependency and greenhouse gas emissions. Recently, number of proposals has been presented for the development of sustainable biofuels production methods for promise for accelerating a shift away from an unsustainable approach to possible sustainable production practices or a sustainable social, economic and environment. This article presents an extensive literature review of the biomass-based renewable energy potential in Pakistan based on current energy scenario and future perspectives. It also highlights the availability of the indigenous and local biomass resources and potential biomass conversion technologies to convert such resources to bioenergy. The drivers for utilization of indigenous biomass resources in future energy mix and challenges regarding awareness among stakeholders and R&D to fill knowledge gaps are economically restraints. The article concludes with suggestions on future directions and policies for effective implementation of biomass based renewable energy production.

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