Klaus Hellgardt

Wastewater treatment: wet air oxidation as a precursor to biological treatment

Abstract The use of wet air oxidation as a pretreatment step in the context of an integrated chemical/biological process was investigated for model organic-containing wastewaters. It was found that the selection of suitable wastewaters and pretreatment conditions (i.e. temperature, residence time, use of catalysts) was significant for the effective application of an integrated process. For the systems under consideration, an integrated process was found to be advantageous for treating a polymer-containing wastewater, while mild wet air oxidation alone may suffice to treat a polyphenol-containing wastewater.

Palladium catalysed heck reactions and allylic substitution reactions using glass bead technology

Abstract The use of controlled-pore glass beads in Heck reactions and palladium catalysed allylic substitution affords the products with low levels of catalyst leaching.

Characterisation of carbon deposits on Ni/SiO2 in the reforming of CH4–CO2 using fixed- and fluidised-bed reactors

Abstract CO2 reforming of methane was investigated with regard to carbon deposition on 4.5 wt% NiO/SiO2 catalyst at 1023 K, 1 atm and a CH4/CO2 ratio of 1.0 employing micro-fluidised- and fixed-bed reactors. A higher catalytic activity (by 20%) was observed in the initial stage (0.5 h) of the fluidised-bed reforming which may be attributed to lesser deactivation of the catalyst compared to fixed-bed operation. Only a limited amount of carbon was deposited in a period of 11 h on stream. In the case of the fixed-bed reactor, a much larger amount of carbon was found on the spent catalyst, particularly, when sampled from the bottom of the bed. TPO results suggest that carbon deposits on the catalyst samples from the fluidised-bed as well as the top of the fixed-bed are rather small and of similar nature. The carbon deposited at the bottom of the fixed-bed reactor contained two distinct species according to XPS results (corresponding to C–O and C–C bonds).

Experimental Study of DI Diesel Engine Performance Using Three Different Biodiesel Fuels

Methyl esters derived from vegetable oils by the process of transesterification (commonly referred as ‘biodiesel’), can be used as an alternative fuel in compression ignition engines. In this study, three different vegetable oils (rape, soy and waste oil) were used to produce biodiesel fuels that were then tested in a four cylinder direct injection engine, typically used in small diesel genset applications. Engine performance and emissions were recorded at five load conditions and at two different speeds. This paper presents the results obtained for measurements of NOx and smoke opacity at the different speed and load conditions for the three biodiesels, and their blends (5 and 50% v/v) with mineral diesel. A simple combustion analysis was also performed where ignition delay, position and magnitude of peak cylinder pressure and heat release rate were examined to asses how the variation of chemical structure and blend percentage affects engine performance. Engine performance and emissions for all of the 5% biodiesel blends were indistinguishable from mineral diesel. However, at higher blends, the rape fuel exhibited better emission and performance characteristics than either the soy or waste fuels. Furthermore; whilst emissions trends varied for each blend and fuel, emissions of smoke were significantly reduced at all speed and load conditions, and NOx was reduced by up to 50% at low loads. It will also be shown that while engine performance was not significantly deteriorated by biodiesel, there was evidence of increased ignition delay with higher blends, and a possible two stage ignition process where mineral diesel ignited earlier than the biodiesel.

Use of numerical taxonomy and journal impact factors in the evaluation of chemical engineering academics’ publications

The paper describes the results of the application of numerical taxonomy and specifically a taxonomic similarity measure (the Gower similarity coefficient) to compare the publication output of a number of senior academics in chemical engineering in both UK and US universities. The measure takes account of both the numbers of articles published, and the impact factors of the journals in which they were published. Using this coefficient, it was found that most of the academics are not similar to the ‘ideal’ chemical engineering researcher, as defined by ISI’s Journal Citation Reports , but some academics, and some departments, are closer to the ideal than others.