Sonic Capture of Condensates Containing Particulates and Dissolved Gases

摘要

The cooled exhaust of coal combustion yields condensates that contain dissolved acidic gases and particulates. Because these condensates are highly corrosive and difficult to trap, power plants often use high exhaust temperatures to prevent condensation. The alternative to this approach is to maximize condensation, and thus maximize emission capture. The first step is to add more water vapor by: (1) slag quenching, which also yields charged droplets, and (2) the use of coal-water slurries, notably for pressurized fluidized beds and coal-fired gas turbines. These techniques can increase water vapor to any desired level, a factor of 2.7 being most promising. Once formed, the condensates must then be trapped. High power sound is known to be effective in condensation control. Recent work shows that a combination of high and low frequencies, applied at optimum directions, reduces the condensates to the level of detection, thereby trapping both small particulates and dissolved gases.