Abstract There is a strong need for transformative sanitation systems in the areas of the world where open defecation habits and/or inadequate sewage treatment methods and facilities exist. This paper describes an innovative thermally efficient solid waste treatment process as a basis for an off-the-grid, non-sewered toilet in order to address this need. Human feces are combusted in a continuous-cyclic manner using two stages of smoldering and catalytic oxidation. It has been shown that thermal coupling of the two stages creates a self-sustained reactor that can combust wet fecal material containing up to 3.2 parts water to 1 part dry matter – equivalent of water content in healthy human feces – without the need for external heating, known as the ultimate challenge in direct combustion of human feces. Furthermore, it has been shown that air flow rate can be reliably used as a controlling mechanism for fecal destruction rate which means the same reactor could be operated for various and varying input rates. The present work demonstrates the potential for manufacturing low-cost, low-energy consuming sanitation systems that are more easily accessible to communities in need of such systems.

Pinch technology has now developed into a powerful tool for heat integration of petroleum refining processes. Each process within the refinery has its own constraints against pinch analysis. In order to overcome these constraints, many applications and their solutions have been presented, such as decomposition policy and pressure drop considerations. These studies show that pinch analysis will only be suitable within the known limitations. In traditional refineries, the hydrocracking process is considered important due to the high pressures. The process converts gas oil feedstock into kerosene, diesel fuel and high-quality gasoline. In this paper, we have focused on the retrofitting of a typical hydrocracking process at Tehran South Refinery (Chevron License) operating at 130-180 atm with significant energy consumption. The potential and opportunities for heat integration in this process were considered. The objective of this study is to demonstrate how to apply alternative heat integration approaches, recover the maximum waste heat and maintain stable production while taking into account the operational constraints and plant equipment limitations. In this survey, several projects were identified which resulted in $870 000 annual saving in energy costs.  2010 Curtin

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The electrical resistivity of ash particles is an important parameter that determines the efficiency of electrostatic precipitators. This systematic study examines the resistivity of recovery boiler precipitator ash as a function of electrical field strength, time of exposure, particle composition, and gas composition and temperature. Synthetic ash and actual ash samples from several pulp mills are used. The results show that most ash samples tested had a resistivity between 109 and 1010 Ω·cm, but one of the samples had an unusually high resistivity, 1012 Ω·cm. The resistivity increases with temperature up to about 140°C, then decreases. At a given temperature, the resistivity decreases with increasing moisture and sulfur dioxide concentration in the gas. Resistivity also increases with an increase in chloride content in the ash, but is not affected by the carbonate, sulfate, and potassium contents. The results imply that recovery boilers burning liquors with high solids and high chloride contents produce ash with higher resistivity, making it more difficult for electrostatic precipitators to capture.