Experiments were carried out on a tubular furnace. The results showed that the released amount of K and Cl increased with the wheat straw share of the blends, meanwhile the released amount of Cl was far more than that of K. Al and Si from coal can capture K to form KAlSixOy, which would promote the release of HCl. The activity of Al and Si increased with the temperature rising. During combustion, Ca and Mg can react with Al and Si, resulting in an increased release of K and a decreased release of HCl indirectly.

The elemental and phase compositions of cornstalk ash are largely different from that of lean coal ash. In comparison with pure lean coal, co-firing of cornstalk and lean coal may result in serious corrosion to the heating surface of superheater. This paper presents a composition comparison between the two ashes by means of Energy Dispersive Spectrometer (EDS) analysis and X-Ray Diffraction (XRD) analysis. A number of experiments were carried out in a tubular furnace to investigate the ash corrosion characteristics. Measured corrosion characteristic curves show the agreement of parabolic rule, and the corrosion is mainly effected by ash compositions and temperature. It was also found that alkali-chloride, alkali metal sulphide in ash and HCl in flue gas significantly aggravate the corrosion. The corrosion speed increases as the temperature increase, and becomes significantly high when the temperature is above 550°C.

In this paper, three detection methods were analyzed to determine the chlorine precipitation from the flue gas: Silver nitrate volumetric analysis (SNVA), Volhard method (VM) and Mercuric thiocyanate spectrophotometric method (MTSM). Results indicated that SNVA and VM were simple and convenient, but unsuitable for the detection of blend fuel due to the high lower limit. MTSM was suitable for biomass and coal co-combustion for its low lower limit and high sensitivity. In addition, MTSM needed less sample solution, which made it more suitable for multiple measurements to reduce errors, and the maximum proportional error was only 3.5%.