Prof Klaus Hellgardt

Tamburic B, Zemichael FW, Crudge P, Maitland GC, Hellgardt Ket al., 2011, Design of a novel flat-plate photobioreactor system for green algal hydrogen production, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, Vol: 36, Pages: 6578-6591, ISSN: 0360-3199

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• Citations: 47

Alshammari Y, Hellgardt K, 2011, Continuous-flow reforming of hydrocarbons underground: Kinetic analysis

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Burgess SJ, Tamburic B, Zemichael F, Hellgardt K, Nixon PJet al., 2011, Solar-Driven Hydrogen Production in Green Algae, ADVANCES IN APPLIED MICROBIOLOGY, VOL 75, Vol: 75, Pages: 71-110, ISSN: 0065-2164

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• Citations: 34

Ong CK, Dennison S, Hellgardt K, Kelsall GHet al., 2011, Evaluation and Modeling of a Photo-electrochemical Reactor for Hydrogen Production Operating under High Photon Flux, Symposium on Industrial Electrochemistry and Electrochemical Engineering General Session/219th Meeting of the Electrochemical-Society, Publisher: ELECTROCHEMICAL SOC INC, Pages: 11-19, ISSN: 1938-5862

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• Citations: 8

Mohamad Daud AR, Millan M, Hellgardt K, Kandiyoti Ret al., 2010, Supercritical water partial oxidation cracking of three-member ring polycyclic aromatic hydrocarbon compounds

Supercritical water partial oxidation cracking of PAH compounds was studied. A three-member ring PAH isomers, i.e., anthracene and phenanthrene were used as model compounds with aqueous hydrogen peroxide as oxidant. At 450°C, anthracene was partially oxidized to mainly 9,10-anthraquinone, 9,10-anthracenedione,2-hydroxy, xanthone, benzoic acid, naphthalene, and phenol while phenanthrene was converted into 4-hydroxy,9-fluorenone, anthraquinone, fluorenone, benzoic acid, naphthalene, and phenol. Increasing the reaction time contributed to the loss of oxygenated functionalities and hence enhanced the formation of neutral aromatic fragments, i.e., naphthalene, biphenyl, and fluorene. This is an abstract of a paper presented at the 19th International Congress of Chemical and Process Engineering and 7th European Congress of Chemical Engineering (Prague, Czech Republic 8/28/2010-9/1/2010).

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Gunvachai K, Hellgardt K, 2010, New solubility model to capture the intrinsic kinetics of biodiesel formation from palm oil, 10AIChE - 2010 AIChE Annual Meeting, Conference Proceedings

A new solubility model, which takes into account the limited solubility between the reactants during the early stage of the reaction and the immiscibility of the reaction by-product, namely glycerol, has been developed to describe the kinetics of the base-catalysed transesterification of palm oil. Associated phase equilibria have been determined and tie lines have been constructed in order to identify the reaction path within the multiphase system. Under conditions of kinetic control (high mass transfer rates), the multiphase system is considered to be limited by interphase solubility, which in turn is modified by the reaction product (methyl esters). It was found that the solubility model constructed offers a good representation of the kinetics of the reaction (Figure 1). A comparison between the solubility model and a conventional pseudo-homogeneous reaction model reveals that for the reaction conditions studied in this work, i.e. 6:1 methanol to oil molar ratio and temperature of 30°C-60°C, due to a very short period of the multiphase stage in relation to that of the homogeneous stage, the latter model also provides a good description of the kinetics of the reaction. The use of a solubility model is deemed more crucial for the transesterification of triglycerides that have extremely limited solubility with methanol or for the reaction carried out at higher methanol to oil molar ratio or lower temperature, in which case the multiphase stage of the reaction would be longer and the assumption of a homogeneous reaction for the whole course of the reaction may no longer hold. In order to be able to collect a sufficient amount of early kinetic data (for data fitting and model comparison), a novel continuous flow reactor (mini-CSTR/PFR combination for segregated flow) had to be developed to determine the intrinsic kinetics of the fast base-catalysed transesterification reaction of palm oil for this purpose. Compared with a conventional batch apparatus, the mini-

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Alshammari Y, Hellgardt K, 2010, Reservoir based hydrothermal reforming of hydrocarbons, 10AIChE - 2010 AIChE Annual Meeting, Conference Proceedings

Enhanced Oil Recovery (EOR) operations may offer a potentially clean and economical method for hydrothermal production of syngas or hydrogen as useful product or energy vector. EOR operations usually employ in situ combustion (using oxygen or air), steam injection and/or CO2 injection. In situ combustion has been studied for a number of years, e.g. the THAI process invented in 1993 by M. Greaves. In this process an air injection well is used to combust heavy oil and thus provides local heat to reduce oil viscosity. The oil is then driven towards a producer well (toe to heal). It is suggested that approximately 80% ooip recovery may be accomplished with the additional benefit of some in situ oil upgrading. Air injection results in the release of an equal amount of CO, CO2 and hydrocarbons. This of course begs the question whether the return gas, which would be used to provide the required electricity for the compressors, could be converted into syngas/hydrogen and thus lead to the production of a clean energy vector. Indeed, is it conceivable to employ, for example, redundant production wells as hydrothermal reactor systems with the explicit injection of oil, steam and air/oxygen and thus remove the need for above ground reformers? In the present work a basic parametric equilibrium study has been carried out on the reactions between crude oil and EOR fluids (air, steam, and CO2) using HYSYS and employing the embedded Gibbs Reactor model. This model allows the thermodynamic analysis of the effect of the molar flowrates of injection fluids (ratio of injection fluid to oil), reservoir pressure, reservoir temperature and water cut on the composition of the produced syngas. Only a few similar investigations have been reported in the literature (Ye et al., 2009, Ersoz et al., 2003, Jeon, 2008). These studies do not normally include crude oils containing sulphur compounds, nitrogen compounds and asphaltenes. Adiabatic steam/air reforming has been compared with adiabatic CO2

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Zotova N, Hellgardt K, Kelsall GH, Jessiman AS, Hii KKMet al., 2010, Catalysis in flow: the practical and selective aerobic oxidation of alcohols to aldehydes and ketones, GREEN CHEMISTRY, Vol: 12, Pages: 2157-2163, ISSN: 1463-9262

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• Citations: 71

OEN A, HELLGARDT K, CHADWICK D, 2010, CYCLIC SULFIDATION REDUCTION OF TRANSITION-METAL MODEL COMPOUNDS - A QUASI IN-SITU XPS STUDY, 5th Workshop on Hydrotreating Catalysis, Publisher: SOC CHIMIQUE BELGIQUE, Pages: 317-324, ISSN: 0037-9646

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• Citations: 5

Tamburic B, Zemichael FW, Maitland GC, Hellgardt Ket al., 2010, Design of a Novel Flat-plate Photobioreactor System for Green Algal Hydrogen Production, Pages: 3-9

Some unicellular green algae have the ability to photosynthetically produce molecular hydrogen using sunlight and water. This renewable, carbon-neutral process has the additional benefit of sequestering carbon dioxide during the algal growth phase. The main costs associated with this process result from building and operating a photobioreactor system. The challenge is to design an innovative and cost effective photobioreactor that meets the requirements of algal growth and sustainable hydrogen production. We document the details of a novel 1 litre vertical flat-plate photobioreactor that has been designed to accommodate green algal hydrogen production at the laboratory scale. Coherent, non-heating illumination is provided by a panel of cool white LEDs. The reactor body consists of two compartments constructed from transparent Perspex sheets. The primary compartment holds the algal culture, which is agitated by means of a recirculating gas flow. A secondary compartment is filled with water and used to control the temperature and wavelength of the system. The reactor is fitted with instruments that monitor the pH, pO2, temperature and optical density of the culture. A membrane-inlet mass spectrometry system has been developed for hydrogen collection and in situ monitoring. The reactor is fully autoclaveable and the possibility of hydrogen leaks has been minimised. The modular nature of the reactor allows efficient cleaning and maintenance.

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• Citations: 1

Streat M, Hellgardt K, 2010, Granular iron hydroxide as an adsorbent for arsenic in water, The Global Arsenic Problem: Challenges for Safe Water Production, Pages: 59-80, ISBN: 9780415575218

Water is essential for sustaining human, animal and plant life. Drinking water contains many trace contaminants, both cationic and anionic. The sources of contamination of the aqueous environment can arise directly from geological sources, factory effluent and waste treatment plants or indirectly from the soil by agricultural or industrial runoff. There are several European Union standards for drinking water that cover thousands of pollutants, e.g. inorganic and organic materials (75/440/EC 1975, 80/778/EC 1980, 98/83/EC 1998). A list of some typical maximum permitted levels of contaminants is given in Table 5.1.

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Tamburic B, Burgess S, Nixon PJ, Hellgardt Ket al., 2010, An Experimental Study of the Growth and Hydrogen Production of C. Reinhardtii, Pages: 47-52

Some unicellular green algae, such as C. reinhardtii, have the ability to photosynthetically produce molecular hydrogen under anaerobic conditions. They offer a biological route to renewable, carbon-neutral hydrogen production from two of nature’s most plentiful resources – sunlight and water. This process provides the additional benefit of carbon dioxide sequestration and the option of deriving valuable products from algal biomass. The growth of dense and healthy algal biomass is a prerequisite for efficient hydrogen production. This study investigates the growth of C. reinhardtii under different cyclic light regimes and at various continuous light intensities. Algal growth is characterised in terms of the cell count, chlorophyll content and optical density of the culture. The consumption of critical nutrients such as acetate and sulphate is measured by chromatography techniques. C. reinhardtii wild-type CC-124 strain is analysed in a 3 litre tubular flow photobioreactor featuring a large surface-to-volume ratio and excellent light penetration through the culture. Key parameters of the hydrogen production process are continuously monitored and controlled; these include pH, pO2, optical density, temperature, agitation and light intensity. Gas phase hydrogen production is determined by mass spectrometry.

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Carver C, Ulissi Z, Ong CK, Dennison S, Hellgardt K, Kelsall GHet al., 2010, Modeling and evaluation of a photoelectrochemical reactor for H₂ production, Symposium on Electrochemical Technologies for Hydrogen Production held during the 217th Meeting of the Electrochemical-Society, Publisher: ELECTROCHEMICAL SOC INC, Pages: 103-117, ISSN: 1938-5862

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• Citations: 6

Zemichael FW, Al-Musa A, Cumming IW, Hellgardt Ket al., 2008, Propene partial oxidation over Au-Ag Alloy and Ag catalysts using electrochemical oxygen, 16th International Conference on Solid State Ionics, Publisher: ELSEVIER SCIENCE BV, Pages: 1401-1404, ISSN: 0167-2738

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• Citations: 9

Richardson DJ, Mason G, Buffham BA, Hellgardt K, Cumming IW, Russell PAet al., 2008, Viscosity of binary mixtures of carbon monoxide and helium, JOURNAL OF CHEMICAL AND ENGINEERING DATA, Vol: 53, Pages: 303-306, ISSN: 0021-9568

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• Citations: 3

Streat M, Hellgardt K, Newton NLR, 2008, Hydrous ferric oxide as an adsorbent in water treatment - Part 3: Batch and mini-column adsorption of arsenic, phosphorus, fluorine and cadmium ions, PROCESS SAFETY AND ENVIRONMENTAL PROTECTION, Vol: 86, Pages: 21-30, ISSN: 0957-5820

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• Citations: 72

Richardson DJ, Mason G, Hellgardt K, Russell PA, Buffham BA, Bates JSet al., 2008, Pore structure in nickel created by ammonia at 873 K, 5th Meeting of the Brazilian-Society-for-Materials-Research, Publisher: SPRINGER, Pages: 665-670, ISSN: 0022-2461

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Streat M, Hellgardt K, Newton NLR, 2008, Hydrous ferric oxide as an adsorbent in water treatment - Part 1. Preparation and physical characterization, PROCESS SAFETY AND ENVIRONMENTAL PROTECTION, Vol: 86, Pages: 1-9, ISSN: 0957-5820

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• Citations: 40

Streat M, Hellgardt K, Newton NLR, 2008, Hydrous ferric oxide as an adsorbent in water treatment - Part 2. Adsorption studies, PROCESS SAFETY AND ENVIRONMENTAL PROTECTION, Vol: 86, Pages: 11-20, ISSN: 0957-5820

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• Citations: 56

Gunvachai K, Hassan MG, Shama G, Hellgardt Ket al., 2007, A new solubility model to describe biodiesel formation kinetics, PROCESS SAFETY AND ENVIRONMENTAL PROTECTION, Vol: 85, Pages: 383-389, ISSN: 0957-5820

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• Citations: 23

Johnson VS, Hellgardt K, Dann SE, White RJet al., 2007, Synthesis and characterisation of a potential ceramic sulfide ion conductor based on the solid solution <i>x</i>CaS:Nd₂S₃, <i>x</i>=0.7-1.0, International Conference on Nonstoichiometric Compounds, Publisher: SPRINGER, Pages: 1948-1954, ISSN: 0022-2461

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• Citations: 4

Illing G, 2007, Protonenleitfähige Polymerelektrolytmembran auf der Basis von Polyanilin, dotiert mit Polysäuren, DE102005031715

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Hellgardt K, Richardson D J, Russell P A, Mason G, Buffham B Aet al., 2007, Model of a non-isothermal tubular ammonia reformer for fuel cell applications, World Review of Science, Technology and Sustainable Development, Vol: 4(2-3), Pages: 161-172

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Riesco N, Mason G, Cumming I W, Russell P A, Hellgardt Ket al., 2007, Measurement of gas mixing volumes by Flux Response Technology, Fluid Phase Equilibria, Vol: 256, Pages: 93-98

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Alqahtani A, Hellgardt K, Holdich R, Cumming Iet al., 2007, Integrated Knowledge Based System for Process Synthesis, 17TH EUROPEAN SYMPOSIUM ON COMPUTER AIDED PROCESS ENGINEERING, Vol: 24, Pages: 437-442, ISSN: 1570-7946

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• Citations: 1

Al-Enezi S, Hellgardt K, Stapley A G F, 2007, Mechanical Measurement of the Plasticization of Polymers by High-Pressure Carbon Dioxide, International Journal of Polymer Analysis and Characterization, Vol: 12, Pages: 171-183

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Gupta Y, Wakeman R, Hellgardt K, 2006, High-productive, nanostructured polyaniline membranes for gas separation, Conference of the European-Membrane-Society (EUROMEMBRANE 2006), Publisher: ELSEVIER SCIENCE BV, Pages: 474-476, ISSN: 0011-9164

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• Citations: 11

Fournier GGM, Cumming IW, Hellgardt K, 2006, High performance direct ammonia solid oxide fuel cell, JOURNAL OF POWER SOURCES, Vol: 162, Pages: 198-206, ISSN: 0378-7753

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• Citations: 89

Richardson D J, Hellgardt K, Mason G, Russell P A, Buffham B Aet al., 2006, Surface treatment of Nickel

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Gupta Y, Wakeman RJ, Hellgardt K, 2006, Enhanced permeability of polyaniline based nano-membranes for gas separation, Journal of Membrane Science, Vol: 282 (1-2), Pages: 60-70

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