This invention relates generally to a method and apparatus for acoustically monitoring the flow of suspended solid particulate matter; and specifically to a method and apparatus for measuring such flow under high temperatures and pressures in multiphase process streams. The invention has particular application in coal gasification processes and the monitoring char flow.
In the process of converting coal into liquid fuels or high and low Btu gases, problems with the flow of particulate matter are most frequently encountered with char, a solid residue that remains after the removal of moisture and volatile matter from coal. Blockage of char feed lines has been a recurrent problem that can lead to serious interruption of the coal conversion process and create serious safety hazards.
Char particles are abrasive and also tend to plug up orifices and to foul up moving parts. Typical operating conditions within the char feed lines in coal gasification processes are 430.degree. C. (800.degree. F.) at a pressure of 11.4 MPa (1650 psi).