John B. Green

Separation of liquid fossil fuels into acid, base and neutral concentrates: 1. An improved nonaqueous ion exchange method

Abstract An improved method is presented for nonaqueous ion exchange separation of liquid fossil fuels into acid, base and neutral fractions. Improvements over previous procedures have been made in the areas of ion exchange resin activation, elution of the neutral compounds, extraction of acids and bases from the resins, and in a better definition the overall properties, strengths and weaknesses of the method. A detailed procedure for applying the method to separations of fuels is presented. In addition, results of its application to different types of fuels and model compound mixtures are included, as well as other data relating to the mechanism of acid-base retention on resins and overall optimization of the usual Chromatographic variables.

Storage stability of marine diesel fuels

Abstract The cause of instability in marine diesel fuels was investigated by ageing several fuels at 65 °C for various periods. Aged and unaged fuel samples were chromatographically separated into acid, base and neutral fractions, and the fractions were analysed in detail to obtain a clearer understanding of the mechanism of colour change and sediment formation. The results suggest that oxidation of neutral compounds to polar intermediates may be a major pathway for sediment formation and darkening of marine diesel fuels. Considerable loss of polar compounds, both those originally present and those newly formed, to sediment was also found. Within a compound class, the more aromatic higher molecular weight members were observed to be the most active in sediment formation.

Kinetics of the reactions of EDTA and coal humic acid with CuO

Abstract The kinetics of cupric ion extraction from solid cupric oxide by two chelating agents was studied. EDTA (disodium ethylenediaminetetraacetic acid) and humic acid (a natural product) were both observed to solubilize CuO at a rate largely independent of chelating agent concentration. A rate law was derived which explained deviations from pure zero order kinetics in terms of surface binding of H2O, OH−, chelating agents and copper chelates to CuO. Through application of the equation, it was shown that humic acid (H.A.) and copper humate (Cu-H.A.) inhibited ionic dissolution of CuO and that EDTA activated the dissociation process. Cu-EDTA had little effect on the rate of dissociation. The change in dissociation rate with varying pH, concentrations of chelating agent and copper chelate, etc. was interpreted in light of the probable effect of each in shifting the equilibrium of bound species on the CuO surface. The initial dissociation rate of CuO in the presence of either chelating agent was on the order of 10−7 m/1-sec in the pH range 9−5.

Absorption of sulphur dioxide by sodium humates

Abstract As part of a programme for assessing the potential of basic humates as stack gas scrubbing media, the reaction of sodium salts of coal derived humic acids (HA) with sulphur dioxide was investigated. The principal absorption mechanism was found to be acid-base: Na-HA(aq) + SO 2 (g) + H 2 O ⇄ HA(s) + HSO t- 3 (aq) + Na + (aq) Soluble sodium Insoluble humic humate acid However, formation of a sulphur dioxide-HA ‘complex’ was observed under conditions (low pH, high temperature) which favoured conversion of a significant fraction (> 5%) of dissolved sulphites to the SO2(aq) ‘H2SO3’ form. Greater complexation of SO2(aq) was observed for HA preparations which had been stored under basic conditions for periods up to two years. Reversibility of absorption and desorption was demonstrated. Similar experiments with hydrogen sulphide revealed no significant reaction with sodium or iron(III) humates.

Sulphur dioxide sorption by humic acid-fly ash mixtures

The sulphur dioxide absorption capabilities of aqueous humic acid-fly ash mixtures were investigated. Humic acid (HA) promotes the dissolution of basic material in fly ash, resulting in the formation of humate salts. These salts absorb SO2 effectively via an acid-base reaction resulting in formation of metal bisulphites and HA as products. The extent of fly ash dissolution in HA is a function of the HAfly ash ratio, with greater dissolution occurring as the ratio increases, until an excess of HA is present. The utilization of base from fly ash for neutralization of S02 is a function of its dissolution, and hence is also dependent on the HAfly ash ratio. Besides neutralization to bisulphite, HA-fly ash mixtures can also absorb SO2 through a specific HA-SO2(aq) interaction. However, the importance of this reaction is relatively small. On the basis of this work, it can safely be predicted that HA-fly ash mixtures would greatly outperform water-fly ash slurries in stack gas scrubbing applications.