Investigation of Combustion and NO/SO2 Emission Characteristics during the Co-Combustion Process of Torrefied Biomass and Lignite.

This paper investigates the combustion characteristics and pollutant emission patterns of the mixed combustion of lignite (L) and torrefied pine wood (TPW) under different blending ratios. Isothermal combustion experiments were conducted in a fixed bed reaction system at 800 °C, and pollutant emission concentrations were measured using a flue gas analyzer. Using scanning electron microscopy (SEM) and BET (nitrogen adsorption) experiments, it was found that torrefied pine wood (TPW) has a larger specific surface area and a more developed pore structure, which can facilitate more complete combustion of the sample. The results of the non-isothermal thermogravimetric analysis show that with the TPW blending ratio increase, the entire combustion process advances, and the ignition temperature, maximum peak temperature, and burnout temperature all show a decreasing trend. The kinetic equations of the combustion reaction process of mixed gas were calculated by Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) kinetic equations. The results show that the blending of TPW reduces the activation energy of the combustion reaction of the mixed fuel. When the TPW blending ratio is 80%, the activation energy values of the mixed fuel are the lowest at 111.32 kJ/mol and 104.87 kJ/mol. The abundant alkali metal ions and porous structure in TPW reduce the conversion rates of N and S elements in the fuel to NO and SO2, thus reducing the pollutant emissions from the mixed fuel.

[Organic mercury tolerance, absorption and transformation in Spartina plants].

Critical concentration of methylmercuric chloride (MeHgCl) in the nutrient solution to which Spartina plants are tolerant is 15 micromol/L, three times higher than that of tobacco plants. After being treated with methylmercuric chloride, total quantity of organic mercury within plants increased and that of nutrient solution decreased greatly so that total quantity of inorganic mercury rose. It is inferred that Spartina plants absorb organic mercury and partially transform organic into inorganic mercury, and then more inorganic mercury is accumulated in underground parts of plants. In addition, inorganic mercury derived from organic mercury moved to solution by diffusion and permeation. In this way, the features Spartina plants exhibit in mercury accumulation and transformation from organic to inorganic mercury are valuable for phytoremediation of environment pollution.