In this article, flow pattern of liquid film and flooding phenomena of a falling film microreactor (FFMR) were investigated using high-speed CCD camera. Three flow regimes were identified as ''corner rivulet flow,'' ''falling film flow with dry patches,'' and ''complete falling film flow'' when liquid flow rate increased gradually. Besides liquid film flow in microchannels, a flooding presented as the flow of liquid along the side wall of gas chamber in FFMR was found at high liquid flow rate. Moreover, the flooding could be initiated at lower flow rate with the reduction of the depth of the gas chamber. CO 2 absorption was then investigated under the complete falling flow regime in FFMR, where the effects of liquid viscosity and surface tension on mass transfer were demonstrated. The experimental results indicate that k L is in the range of 5.83 to 13.4 Â 10 À5 m s À1 and an empirical correlation was proposed to predict k L in FFMR.

JP-10 is a potential endothermic hydrocarbon fuel (EHF) with a high energy density for the regenerative cooling technology of advanced aircrafts. In this work, pyrolysis and coking of JP-10 were experimentally studied using an electrically heated tube as a flowing reactor under supercritical conditions (4.5 MPa, 550–735 °C). For the supercritical pyrolysis, dicyclopentadiene, exo-TCD4e, and indane/indene were observed with relatively higher selectivity at low conversion, and the selectivities of typical products (ethene, propene, CPD, cyclopentene, and benzene) were lower compared with that under atmospheric pressure, possibly because of the enhanced bimolecular reactions. The heat sink of JP-10 was approximately 2.5 MJ/kg ascribed to the severe coke formation during the pyrolysis. Further characterizations on cokes indicated that the coke in the bulk fluid was about 70–170 times higher than that deposited on the wall, attributed to rapid formation of polycyclic aromatic hydrocarbons (PAHs) of pyrolysis products rather than the wall catalysis.

No abstract

No abstract

No abstract

BackgroundEthanol photosynthetic production based on cyanobacteria cell factories utilizing CO2 and solar energy provides an attractive solution for sustainable production of green fuels. However, the scaling up processes of cyanobacteria cell factories were usually threatened or even devastated by biocontaminations, which restricted biomass or products accumulations of cyanobacteria cells. Thus it is of great significance to develop reliable biocontamination-controlling strategies for promoting ethanol photosynthetic production in large scales.ResultsThe scaling up process of a previously developed Synechocystis strain Syn-HZ24 for ethanol synthesis was severely inhibited and devastated by a specific contaminant, Pannonibacter phragmitetus, which overcame the growths of cyanobacteria cells and completely consumed the ethanol accumulation in the cultivation systems. Physiological analysis revealed that growths and ethanol-consuming activities of the contaminant were sensitive to alkaline conditions, while ethanol-synthesizing cyanobacteria strain Syn-HZ24 could tolerate alkaline pH conditions as high as 11.0, indicating that pH-increasing strategy might be a feasible approach for rescuing ethanol photosynthetic production in outdoor cultivation systems. Thus, we designed and evaluated a Bicarbonate-based Integrated Carbon Capture System (BICCS) derived pH-rising strategy to rescue the ethanol photosynthetic production in non-sterilized conditions. In lab scale artificially simulated systems, pH values of BG11 culture medium were maintained around 11.0 by 180 mM NaHCO3 and air steam, under which the infection of Pannonibacter phragmitetus was significantly restricted, recovering ethanol production of Syn-HZ24 by about 80%. As for outdoor cultivations, ethanol photosynthetic production of Syn-HZ24 was also successfully rescued by the BICCS-derived pH-rising strategy, obtaining a final ethanol concentration of 0.9 g/L after 10 days cultivation.ConclusionsIn this work, a novel product-consuming biocontamination pattern in cyanobacteria cultivations, causing devastated ethanol photosynthetic production, was identified and characterized. Physiological analysis of the essential ethanol-consuming contaminant directed the design and application of a pH-rising strategy, which effectively and selectively controlled the contamination and rescued ethanol photosynthetic production. Our work demonstrated the importance of reliable contamination control systems and strategies for large scale outdoor cultivations of cyanobacteria, and provided an inspiring paradigm for targeting effective solutions.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-017-0765-5) contains supplementary material, which is available to authorized users.

No abstract

No abstract