Kinetics of thermal degradation of a Japanese oil sand

Thermal degradation characteristics of a Japanese oil sand at different heating rates (10, 20, and 30 °C/min), and 30 ml/min air flow rate have been investigated. The kinetic parameters have been calculated based on three stages of weight loss and/or the conversion of the sample. These include, stage 1 (SI): volatilization of moisture content and the light hydrocarbon (20–227 °C), stage 2 (SII): combustion of heavy hydrocarbon (227–527 °C), and stage 3 (SIII): oxidative decomposition of carbonaceous organic matter (502–877 °C). The results showed that the rate of change of the oil sand conversion with time $\left(\frac{d\alpha }{\mathit{dt}}\right)$ was affected by the heating rate. The time taken by the system to reach 0.99 conversion was observed as 85, 50, and 35 min at the heating rates of 10, 20, and 30 °C/min, respectively. The frequency factor, A, at SI was between 0.09 and 0.54 min^?1, while the activation energy, E_a, was 11.2–12.5 KJmol^?1 (the percentage weight loss, W_t, was 0–3.6 %w/w; and the conversion, α, was 0–0.2.). At SII, the values of A and E_a were 2.1–5.5 min^?1 and 17.6–19 KJmol^?1, respectively (W_t = 3.1–15.88 %w/w; α = 0.17–0.86.). The value of A at SIII was 5.5E11–1.1E13 min^?1, while E_a was 160–200 KJmol^?1 (W_t = 15.33–17.99 %w/w; and α = 0.84–0.99).     

Adsorption separation of condensate oil from produced water using ACTF prepared of oil palm leaves by batch and fixed bed techniques

A novel method is applied to produce amorphous carbon thin film (ACTF) from oil palm leaves. The novel prepared ACTF is in the form of thin films like graphene sheets having winding surface. ACTF was characterized by different methods of characterization: FTIR, BET, SEM, EDX, TEM, and Raman. ACTF employed as an adsorbent to separate emulsified condensate oil from synthetic produced water as a treatment process before reinjection in oil reservoirs. The adsorption performance of batch and fixed bed adsorption systems were investigated. Contact time, initial concentration of condensate oil ($C_o$ = 100–2500 mg/l) and temperature were studied by batch experiments. The obtained results indicated that the adsorption capacity and the removal efficiency increased with time up to 132.77 mg condensate/g adsorbent and 66.38% respectively, within 6 h equilibrium time at 308 K. The thermodynamic adsorption experiments conducted at 288, 308 and 318 K, referring exothermic nature of the adsorption process.The performance study of fixed bed adsorption described through the breakthrough curves concept with two parameters: column bed heights (5, 10 and 15 mm) and flow rate (2.2, 5 and 8.4 ml/min). Two models (Thomas and Yoon-Nelson models) were applied to expect different parameters of fixed bed as adsorption capacity and time need for 50% breakthrough. The results exhibited that 2.2 ml /min feed flowrate and 5 mm bed height at 1000 mg/l initial oil condensate concentration were the optimum conditions for the ACTF column. The experimental breakthrough curves showed acceptable fit with the calculated breakthrough profiles obtained by Thomas model.     

Smallholder dairy processing in Zimbabwe: hygienic practices during milking and the microbiological quality of the milk at the farm and on delivery

The hygiene practices during milking and the microbiological quality of milk at the farm and on delivery at three smallholder dairies in Zimbabwe were studied. Petrifilm™ was used for the determination of Escherichia coli, coliforms and aerobic mesophilic counts (AMC). Using AMC Petrifilms™ as contact plates, 83% (n=66) of the utensils used for milking had >300 cfu per 20 cm². Of milk samples at the farm, 95% (n=24) had E. coli counts $\text{<10}{}^1\text{cfu}\text{ml}{}^{\mathrm{-1}}$, and all had $\text{AMC}\text{<10}{}^5\text{cfu}\text{ml}{}^{\mathrm{-1}}$. On delivery at the dairy, the proportion of milk samples with $\text{AMC}\text{>10}{}^5\text{cfu}\text{ml}{}^{\mathrm{-1}}$ was 28%. The increase in number of microorganisms in the milk was correlated with factors which would increase delivery time.