Experimental and modeling study of kinetics for methane hydrate formation in a crude oil-in-water emulsion

A low-viscosity emulsion of crude oil in water can be believed to be the bulk of a flow regime in a pipeline.To differentiate which crude oil would and which would not counter the blockage of flow due to gas hydrate formation in flow channels,varying amount of crude oil in water emulsion without any other extraneous additives has undergone methane gas hydrate formation in an autoclave cell.Crude oil was able to thermodynamically inhibit the gas hydrate formation as observed from its hydrate stability zone.The normalized rate of hydrate formation in the emulsion has been calculated from an illustrative chemical affinity model,which showed a decrease in the methane consumption（decreased normalized rate constant） with an increase in the oil content in the emulsion.Fourier transform infrared spectroscopy（FTIR） of the emulsion and characteristic properties of the crude oil have been used to find the chemical component that could be pivotal in selfinhibitory characteristic of the crude oil collected from Ankleshwar,India,against a situation of clogged flow due to formation of gas hydrate and establish flow assurance.

Phosphate-induced interfacial electronic engineering in VPO_(4)-Ni_(2)P heterostructure for improved electrochemical water oxidation

Anodic oxygen evolution reaction(OER)is the key bottleneck for water electrolysis technique owing to its sluggish reaction kinetics.Interfacial engineering on the rationally designed heterostructure can regulate the electronic states efficiently for intrinsic activity improvement.Here,we report a co-phosphorization approach to construct a VPO_(4)-Ni_(2)P heterostructure on nickel foam with strongly chemical binding,wherein phosphate acts as electronic modifier for Ni_(2)P electrocatalyst.Profiting from the interfacial interaction,it is uncovered that electron shifts from Ni_(2)P to VPO_(4)to render valence increment in Ni species.Such an electronic manipulation rationalizes the chemical affinities of various oxygen intermediates in OER pathway,giving a substantially reduced energy barrier.As a result,the advanced VPO_(4)-Ni_(2)P heterostructure only requires an overpotential of 289 mV to deliver a high current density of 350 mA/cm^(2)for OER in alkaline electrolyte,together with a Tafel slope as low as 28 mV/dec.This work brings fresh insights into interfacial engineering for advanced electrocatalyst design.

The competitive and synergistic effect between adsorption enthalpy and capacity in D_(2)/H_(2)separation of M_(2)(m-dobdc)frameworks

Hydrogen isotope separation is a challenging task due to their similar properties.Herein,based on the chemical affinity quantum sieve(CAQS)effect,the D_(2)/H_(2)separation performance of M_(2)(m-dobdc)(M=Co,Ni,Mg,Mn;m-dobdc^(4-)=4,6-dioxido-1,3-benzenedicarboxylate),a series of honeycomb-shaped MOFs with high stability and abundant open metal sites,are studied by gases sorption and breakthrough experiments,in which two critical factors,gas uptake and adsorption enthalpy,are taken into consideration.Among these MOFs,Co_(2)(m-dobdc)exhibits the longest D_(2)retention time of 180 min/g(H_(2)/D_(2)/Ne:1/1/98)at 77 K because of its second-highest adsorption enthalpy(10.7 kJ/mol for H_(2)and 11.8 kJ/mol for D_(2))and the best sorption capacity(5.22 mmol/g for H_(2)and 5.49 mmol/g for D_(2))under low pressure of 1 kPa and 77 K,which make it a promising material for industrial hydrogen isotope separation.Moreover,the results indicate that H_(2)and D_(2)capacities under low pressure(about 1 kPa)dominate the final D_(2)/H_(2)separation property of MOFs.