Condition Monitoring for Twin-Fluid Nozzles with Internal Mixing

Liquid sprays of water are frequently used in air pollution control for gas cooling purposes and for gas cleaning. Twin-fluid nozzles with internal mixing are often used for these purposes because of the small size of the drops produced. In these nozzles the liquid is dispersed by compressed air or another pressurized gas. In high efficiency scrubbers for particle separation, several nozzles are operated in parallel because of the size of the cross section. In such scrubbers, the scrubbing water has to be re-circulated. Precipitation of some solid material can occur in the liquid circuit, caused by chemical reactions. When such precipitations are detached from the place of formation, they can partly or totally block the liquid flow to a nozzle. Due to the resulting unbalanced supply of the nozzles with water and gas, the efficiency of separation decreases. Thus, the nozzles have to be cleaned if a certain fraction of blockages is reached. The aim of this study was to provide a tool for continuously monitoring the status of the nozzles of a scrubber based on the available operation data (water flow, air flow, water pressure and air pressure). The difference between the air pressure and the water pressure is not well suited for this purpose, because the difference is quite small and therefore very exact calibration of the pressure measurement would be required. Therefore, an equation for the reference air flow of a nozzle at the actual water flow and operation pressure was derived. This flow can be compared with the actual air flow for assessment of the status of the nozzles

Highly modular protein micropatterning sheds light on the role of clathrin-mediated endocytosis for the quantitative analysis of protein-protein interactions in live cells

Protein micropatterning is a powerful tool for spatial arrangement of transmembrane and intracellular proteins in living cells. The restriction of one interaction partner (the bait, e.g., the receptor) in regular micropatterns within the plasma membrane and the monitoring of the lateral distribution of the bait’s interaction partner (the prey, e.g., the cytosolic downstream molecule) enables the in-depth examination of protein-protein interactions in a live cell context. This study reports on potential pitfalls and difficulties in data interpretation based on the enrichment of clathrin, which is a protein essential for clathrin-mediated receptor endocytosis. Using a highly modular micropatterning approach based on large-area micro-contact printing and streptavidin-biotin-mediated surface functionalization, clathrin was found to form internalization hotspots within the patterned areas, which, potentially, leads to unspecific bait/prey protein co-recruitment. We discuss the consequences of clathrin-coated pit formation on the quantitative analysis of relevant protein-protein interactions, describe controls and strategies to prevent the misinterpretation of data, and show that the use of DNA-based linker systems can lead to the improvement of the technical platform

Illustrating the effect of viscoelastic additives on cavitation and turbulence with X-ray imaging

The effect of viscoelastic additives on the topology and dynamics of the two-phase flow arising within an axisymmetric orifice with a flow path constriction along its main axis has been investigated employing high-flux synchrotron radiation. X-ray Phase Contrast Imaging (XPCI) has been conducted to visualise the cavitating flow of different types of diesel fuel within the orifice. An additised blend containing Quaternary Ammonium Salt (QAS) additives with a concentration of 500 ppm has been comparatively examined against a pure (base) diesel compound. A high-flux, 12 keV X-ray beam has been utilised to obtain time resolved radiographs depicting the vapour extent within the orifice from two views (side and top) with reference to its main axis. Different test cases have been examined for both fuel types and for a range of flow conditions characterised by Reynolds number of 35500 and cavitation numbers (CN) lying in the range 3.0–7.7. It has been established that the behaviour of viscoelastic micelles in the regions of shear flow is not consistent depending on the cavitation regimes encountered. Namely, viscoelastic effects enhance vortical (string) cavitation, whereas hinder cloud cavitation. Furthermore, the use of additised fuel has been demonstrated to suppress the level of turbulence within the orifice

The Use of Agricultural Residues, Wood Briquettes and Logs for Small-Scale Domestic Heating

Large amounts of agricultural residues are produced annually in the UK alone, which presents a significant biomass energy resource. It has limited availability in briquetted form in the UK but is widely used, particularly in Asia. The aim of this work is to assess the emission from briquetted agricultural residues to wood fuel, including commercial wood briquettes, when utilised in a 5 kW domestic heating stove. Other straw-type materials, sugarcane bagasse, Miscanthus, were also investigated. The combustion behaviour depended on the chemical and physical nature of the briquettes. Results indicate that fuel choice is an important consideration for emission reduction. Fuel-N directly correlates to emitted NOx and all the fuels studied had NOx emissions below the EU regulation limit. While agricultural residues can be relatively high in Cl and S, there is evidence of in-situ capture of HCl and SO2 by calcium salts in the fuel ash. Particulate emissions correlate with the volatile matter in the fuel, but also are influenced by the quality/durability of the briquette. The briquettes performed well compared to wood logs, and while there is a fuel-type influence on emissions, it is also clear that briquettes from optimised manufacture can be lower emitting than wood logs

Acidic extraction and precipitation of heavy metals from biomass incinerator cyclone fly ash

Biomass incineration is increasingly used for the generation of heat and/or electricity. After incineration two ash fractions remain. Bottom ashes (the coarser ash fraction) can usually be used as fertilizing agent on fields as it contains valuable elements for soils and plants and only minor concentrations of heavy metals. Fly ashes (the finer ash fraction) are in most cases disposed as their heavy metal concentrations are too high for a usage as soil enhancer. In this study highly heavy metal contaminated fly ash has been cleaned through extraction with hydrochloric acid. The heavy metals were removed from the extract by precipitation with sodium hydroxide. After the cleaning procedure the ash can be pelletized and be returned to the soils