Phosphorous Transformation during Coal and Sewage Sludge Co-Combustion

Abstract

Sewage sludge (SS) contained considerable phosphorous resource and SS incineration technology had become an important method to reuse SS. To alleviate the difficulty of SS mono-combustion caused by its low heating value, high-rank fuels should be introduced. Effects of SS and coal co-combustion on phosphorus fixation rate in ash were studied through drop tube furnace. It was concluded that rising temperature increased the fixation rate of phosphorus in SS ash. Due to the obvious high calcium content in Xiaolongtan coal (XLT), the co-combustion of SS and XLT effectively increased the fixation rate of phosphorus in ash and phosphorous capture by solid minerals was improved by temperature increase. In the meanwhile, more XLT introduced more calcium into the combustion system, which captured more phosphorous in ash. Whereas, there were just a small quantity of calcic and magnesian minerals in Xiheishan coal (XHS) and as a result, higher temperature accelerated phosphorous emission. The fixation rate of phosphorus during co-combustion of SS and XHS was not significantly affected by the different proportions of XHS. Finally, the co-combustion of 70 % XLT and 30 % SS effectively fixed phosphorus at 1000 °C, where the fixation rate in ash was risen dramatically to as high as 93.29 %.

Review of Phosphorus Chemistry in the Thermal Conversion of Biomass: Progress and Perspectives

“…Symbols with solid fill represent 96 biomasses compiled in this work distributed among the four categories: 25 grain- and seed-based biomasses, , , , , , , , , – 21 algae, ,− 19 animal biomasses, , , , , – and 31 sewage sludges , , , , , , , – Symbols with stripes represent 75 biomasses from the Phyllis2 database distributed among the four categories: 8 Grain- and seed-originated biomasses, 11 algae, 35 animal biomasses, and 21 sewage sludges. The hollow circles represent 621 biomasses in the Phyllis2 database not belonging to any of the four categories (char, fossil fuels, ashes, and nonorganic residues are not included).…”

“…Since no systematic compilation of phosphorus-rich biomass is available in the literature, the data for 96 different biomasses from studies relating to thermal conversion are compiled in this review (refs , , , , – , , , , , , – ). The amount of phosphorus in these biomasses is shown in Figure .…”