•A stable CdS@g-C3N4 core@shell photocatalysis was successfully prepared.•The core@shell hybrid exhibited enhanced hydrogen evolution from water.•The enhanced photocatalytic activity was due to the promoted charge transfer.A novel visible-light-active CdS@g-C3N4 photocatalyst was synthesized via a chemisorption method. This core@shell structure catalyst exhibited enhanced photocatalytic H2 production activity under visible-light (λ ≥ 420 nm) irradiation. The nano-sheet g-C3N4 was successfully coated on CdS nanoparticles with intimate contact. When the content of g-C3N4 in the hybridized composite is 3 wt. %, the hydrogen-production rate of the CdS@g-C3N4 is 2.5 and 2.2 times faster than pure CdS and bulk g-C3N4, respectively. Superior stability was also observed in the cyclic runs. The improvement in stability and activity result from the ability of the π-conjugated g-C3N4 material in transporting photo-induced holes. The core@shell structure promoted separation of the photo-generated electron-hole pair and accelerated the emigration speed of the hole from the valence band of CdS. This effect also results in a greatly improved amount of hydrogen production. The possible mechanism for the photocatalytic activity and stability of CdS@g-C3N4 are tentatively proposed.

•Ethylene recovery from refinery dry gas using a novel hybrid hydration–absorption (HHA) process.•Plate type column to be the physical base of HHA column model.•First principle steady state model of HHA column.•Vapour–liquid–water–hydrate (V–L–W–H) four phases involved in the system.•Three case studies for different C2H4 concentrations in gas feed, L/G ratios and temperature profiles.Effective recovery of ethylene from dry gas plays an increasingly important role to improve economic performance of refineries. Conventional approaches such as cryogenic separation and cold oil absorption are energy consuming. Hybrid hydration–absorption (HHA) process may be an effective way as hydrate formation takes place at temperature near the icing point. This paper aims to study the HHA column, which is the heart of the HHA process, through modelling and process analysis. A detailed steady state model was developed in gPROMS® for this vapour–liquid–water–hydrate (V–L–W–H) four phases system. A base case was analysed with real industry data as inputs. The composition distribution profiles inside the column were explored and the key parameters related with kinetics-controlled hydration process were investigated. Three case studies were carried out for different C2H4 concentrations in gas feed, L/G ratios and temperature profiles respectively. The results show (a) the separation performance of CH4 and C2H4 in the HHA process remains significant for big range of C2H4 feed concentration; (b) L/G ratio has a great impact for hydrate formation and the separation performance of CH4 and C2H4 improves when L/G ratio increases until reaching an optimal point; and (c) a cooling system is required to draw out the heat generated inside the HHA column so that the operating temperature of each plate can be at the temperature near the icing point to retain hydrate formation. This study indicates that the HHA process may be a more promising approach to recover ethylene from refinery dry gas in future industry application.

•Reviewed synergetic photoelectrocatalytic reactors and environmental applications.•Discussed photoelectrocatalytic reactor design parameters.•Introduced integration of photoelectrocatalysis and microbial/photocatalytic fuel cell.•Made suggestions regarding future work on photoelectrocatalysis and reactor design.Integrating electrochemistry with photocatalytic technology, photoelectrocatalysis has been identified as a superior candidate to debottleneck photocatalytic processes. Photoelectrocatalysis involves a photocatalytic system to which an external positive bias is applied, which can significantly increase the rates of photocatalytic reactions by driving the photo-generated electron–hole pairs in opposite directions, reducing their recombination rates. The design of a cost-efficient photoelectrocatalytic reactor plays a critical role in the ultimate acceptance of this promising technology in industry for environmental remediation as well as other applications. In this study, photoelectrocatalysis and associated novel reactor designs reported in recent years are reviewed and discussed. Some of the topics which are discussed in this study include various reactor configurations with different illumination sources, photocatalyst utilization modes, and electrodes as well as composite systems incorporating solar cells in addition to microbial and photocatalytic fuel cells. Future efforts are suggested to push the industrial application of photoelectrocatalysis out of its infancy.

Liquid distributor is a very import internal for distillation columns. Pre-distributor is usually set on the top of distributor for initial distribution. Fluid flow in pre-distributor is a complex system of variable mass flow with many orifices and sub-branches. Consequently, the two phase modeling of pre-distributors was carried out and the homogeneous model with free surface model was applied. The numerical method was validated by comparing with experimental data. Using the simulated results for different pre-distributors, the impacts of inflow rate, location and orientation upon the outflow distribution were investigated. Furthermore, influences of the outflow distribution for pre-distributor on liquid uniformity in trough were also analyzed. The conclusions can be adopted for the structural design of liquid distributor and pre-distributor of large scale.