Back mixing device for pneumatic conveying systems

A back mixing device for use with a flow of solids having a varying flow rate in a pneumatic system for use with a gasification system, the back mixing device comprising:

• a nozzle having a first nozzle end and a second nozzle end, wherein the flow of solids enters the first nozzle end and exits the second nozzle end;
• a chamber in communication with the second nozzle end, wherein the chamber comprises an expanded area leading to a restriction, wherein the expanded area is in communication with the second nozzle end and the restriction is downstream of the expanded area;
• an exit comprising a first exit end and a second exit end, wherein the restriction is in communication with the first exit end;
• and
• one or more back mixing gas lines configured to inject a flow of back mixing gas into the flow of solids, wherein the one or more back mixing lines comprise a nozzle line exiting into the nozzle, wherein the nozzle line is configured to inject the flow of back mixing gas into the flow of solids at the nozzle to create a dispersion pattern about the nozzle,
• wherein the expanded area and the restriction are configured to create a recirculation pattern in the flow of solids within the chamber to smooth the varying flow rate though the back mixing device.