Abstract: The present invention relates to a method for preparation of a powder with no unpleasant odor at a higher &bgr;-glucans content and a larger bulk density but with a smaller bacterial number, from the fruit body of Maitake or Yamabushitake, comprising immersing the fruit body of Maitake or Yamabushitake in a heated aqueous acid solution followed by drying and grinding. The aqueous acid solution includes aqueous solutions of inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid and edible organic acids such as acetic acid, citric acid, malic acid, tartaric acid and succinic acid. Acetic acid or citric acid is preferable in terms of cost and effect.

Abstract: A waste heat recovery boiler comprising heat exchange rate switching means for controlling the rate of heat exchange between an exhaust gas and feedwater in a heat exchanger by changing the state of the feedwater in accordance with the concentration of sulfur oxides in the exhaust gas, thereby maintaining the temperature at which low temperature corrosion due to the exhaust gas is prevented in a downstream portion of the heat exchanger in the direction in which the exhaust gas flows. Accordingly, it is possible to achieve the maximum efficiency of heat recovery since the phenomenon of steaming in the heat exchanger is eliminated irrespective of whether the kind of exhaust gas is a dirty gas or a clean gas.

Abstract: Heat recovery boiler equipment comprising high and low pressure boiler drums and high and low pressure evaporators is disclosed. A recirculation pipeline system is also disclosed in which a control device is provided to control the flow rate of recirculated feed water to maintain a temperature below which cold corrosion occurs. The recirculation of feed water allows for a shorter starting time during restart. Additionally, pressure can be held at a predetermined value to prevent corrosion due to the intrusion of air.