Spray drying has gradually become an effective method for large-scale preparation of oxygen carriers as a result of its unique advantages (high efficiency, scalable production, etc.). However, expensive chemical or commercial powder is usually used as raw material in spray drying granulation. The main objective of this work is to reduce the cost of a spray-drying-derived oxygen carrier through using cheap natural ores as raw materials and optimizing the preparation process. Considering that hematite is cheap but less active in chemical looping combustion (CLC) processes, while copper ore has high oxygen carrying capacity and good reactivity but suffers from sintering at a high temperature, the bi-ore oxygen carrier is prepared by the spray drying granulation method in this work using copper ore and hematite fine powders as raw materials with the addition of a suitable dispersant and binder. Two kinds of oxygen carriers are successfully prepared by the spray drying method, Fe100 (the mass ratio of hematite is 100%) and Cu20Fe80 (the mass ratio of copper ore/hematite is 20:80%), and their performance is evaluated in a batch fluidized bed reactor. The reactivity of Cu20Fe80 is superior than that of Fe100 to char gasification products. The effects of the temperature, oxygen/fuel ratio, and coal rank on the coal-derived CLC performance of Cu20Fe80 are further examined. The temperature of 950 °C is the optimal choice with the highest reaction rate and CO2 yield. The gasification rate is fast using the low-rank coals as fuels, i.e., Chifeng lignite and Shenhua bituminous coal. Moreover, Cu20Fe80 exhibits good stability during the redox test of more than 10 cycles. The used oxygen carrier particles still maintain the abundant pore structure well without the sintering phenomenon. Additionally, the results of scanning electron microscopy with energy-dispersive spectrometry indicate that there is almost no decrease in the relative content of Cu elements after the cyclic tests. This work demonstrates that the spray-drying-derived Cu20Fe80 particle is a promising choice as an oxygen carrier for industrial application of the CLC process.

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This article uses the thermal analysis to study the kinetics characteristics of Polyurethane foam. The partially oxidized and non oxidized materials were used to study the variation of reaction of the smoldering, and the mechanism of function and activation energy of two substances was obtained. The result show that the oxygenolysis of the non oxidized Polyurethane foam belongs to the second-level chemical reaction, while the oxygenolysis of partially oxidized belongs to the first-level chemical reaction; the oxidization reaction of Polyurethane foam is a process which have lots of reaction steps to mutual promote as well as connection with each steps ; Through the smoldering experiment verify that the response characteristics of the two substances under the same heat flux to a certain extent, and the results agree well with the calculated activation energy.

Aiming at the building in city, the dangerous sources in construction are analyzed. Some hazardous factors, which are fountains of the accidents, are certainly made. By accidental types analyzed, accident positions analyzed and accident-engineering sorts analyzed; the complexity and authenticity of accident sources in construction can be distinctly set forth. Some safety control measures are made, which can be used to reduce accidents and advance whole safety supervising level in construction.