• Energy Research

The application of biomass as a co-feed in coal power plants and in standalone biomass power plants, as well as in char production for soil remediation, is a currently important issue. This paper reports on the investigation of biochar formation from agricultural waste crops that are used for soil upgrading, but which do not meet the standards of EU crops, as well as largescale food processing waste. These were compared to test results from basket willow, which is commonly used for energy generation. Food industry waste is often produced in cities on a large scale and is generally easier to process due to lack of other stream components. The key parameters, namely, the content of volatiles, energy content of the formed biochar and the composition of the ash, were determined for a number of herbaceous materials locally available in the European Union. All of them can be used as a cheap source of biochar. A novel procedure of capturing volatiles and hence minimizing the PAH content in the biochar, as well as enabling the recovery of energy from the volatiles is presented. Knowledge of the composition and form of elements in ash is very important for designing ash management systems if co-combustion is implemented. The aim of this study was to determine if the types of biomass are better suited for biochar production or energy generation.

The activity of iodine‐modified MgO in transfer hydrogenation of acrolein with alcohols can be significantly higher than that of unmodified MgO. Data from literature and our previous studies indicate that the initial source of a halide influences the surface properties and hence the activity of the obtained catalytic system. The aim of this paper is to present a systematic study on the influence of the initial source of a halide on the activity and surface properties of MgO‐based catalysts. For the sake of comparison, results for an MgO sample subjected to the same procedure as the iodine‐modified catalysts (MgO‐CH3OH) are included in the manuscript. The following order of activity was observed: MgO‐I2 > MgO‐MgI2 > MgO‐HI >> MgO‐ KI > MgO = MgO‐CH3OH. The second part of the study consisted of characterization studies aimed at determining the strengths of Brønsted basic and acidic sites, total concentrations of acidic and basic sites, topography of the surfaces, elemental composition, differences in the chemical environment of the surface ions, as well as relative amounts of different bands in an attenuated total reflectance–Fourier transform infrared spectrum, which correspond to the bonds present on the surface of the samples. Some parameters were independent of the iodine precursor used (eg, the breadth of the Mg 2p signal), whereas others strongly varied from one sample to another (eg, the range of strengths of the Brønsted acidic and basic sites). The ratio of 2 carbonate bands of the attenuated total reflectance–Fourier transform infrared spectra of the modified catalysts shows a trend which corresponds to the order of activity.

There is growing recognition that the degradation of plastics in the environment is a serious problem. This study investigated and reported on the feasibility of removing end-of-life plastics from circulating in the environment. The specific example focuses on non-recyclable plastics found in a waste diversion program for compostable materials, known as the Green Bin Program. The purpose of this study was to identify and quantify the types of polymers in this stream, as well as to determine if it could be successfully turned into char without separation of its components. The measurements show that polyethylene (72 wt.%), polypropylene (14 wt.%) and polyethylene terephthalate (12 wt.%) are the main constituents of this stream, with minor contributions from polybutylene adipate terephthalate (PBAT), polyvinyl alcohol (PVA), poly methyl methacrylate (PMMA), polystyrene (PS), Nitrile rubber and Nylon. Samples of the as-received waste containing plastics and fibrous material were subjected to a slow pyrolysis process. The yield of the char product depended on the conditions of the pyrolysis and a strong synergistic effect was noted when both the plastic and fibrous materials were co-pyrolyzed. The study of variable pyrolysis conditions, along with DTA-TGA-MS studies on the mechanism of the char formation, indicate that the positive effect results from enhanced interaction of plastics with air, in the presence of fibrous material, during the initial/pre-treatment step.

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.