STUDY OF DENSE PHASE COHESIVE COAL TRANSPORT IN PLUGS: QUARTERLY REPORT, APRIL-JULY 1988

The transport loop for the continuous plug flow conveying of cohesive fine coal was installed and operative. It consisted of 40 feet 1 inch steel pipe connected to a pressurized hopper. Three feet of transparent PVC pipe for the viewing section was included in the test loop after every 10 foot section of the steel pipe. Three light probe sensing stations were installed along the pipeline to measure the plug length, plug velocity, and monitor the plug motion. One of the properties of plug flow of cohesive fine coal is that the plug must be longer than the critical plug length. If the instantaneous plug length at any point along the pipeline is shorter than the critical plug length, the plug will collapse and be deposited on teh bottom of the pipe. to ensure the instantaneous plug length is longer than the critical plug length at any distance along the pipeline, we must begin with an initial plug length longer than the critical plug length of the coal. We found that the minimum initial plug lengths for -200 Mesh (75 micron) of Pittsburgh, Montana, and Virginia coals were 3 feet. Therefore, we decided to study the coal plug flow behavior with initial plug lengths of 3 feet, 4 feet, and 5 feet. Plug flow conveying of cohesive powder can be roughly defined as the conveying of the powder below 1 m/s. If the air velocity is above 1 m/s, dense phase conveying will be observed. Initially, after several attempts, we were unable to transport the coal at velocity of 1 m/s because the steel pipes were too rough. Thus we treated the pipe roughness by blowing the coal at air velocity of 2 m/s. Then, gradually the air velocities were reduced to 1 m/s. To date we are successfully transporting the coal at 1 m/s for distance of 40 feet with initial plug lengths 3, 4, and 5 feet.

• Corporate Authors:

  Pittsburgh University, Pittsburgh

  Department of Chemical and Petroleum Engineering
  Pittsburgh, PA  United States  15213
• Authors:
  • KLINZING, G E
• Publication Date: 1988

Media Info

• Pagination: 10 p.

Subject/Index Terms

• TRT Terms: Coal; Cohesion; Density; Pipe flow; Plugs (Fillers); Slurry
• Old TRIS Terms: Slurries
• Subject Areas: Highways; Hydraulics and Hydrology; I26: Water Run-off - Freeze-thaw;

Filing Info

• Accession Number: 00484728
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: DE88015678/WTS
• Files: TRIS
• Created Date: Jun 30 1989 12:00AM