¦COFIRE Flow Property Tests Cohesive strength: Used to calculate opening sizes to avoid flow stoppages due to cohesive arching and ratholing. Measured as a function of consolidating pressure in accordance with ASTM Standard D6128.
Interlocking strength: Used to calculate opening sizes to avoid flow stoppages due to mechanical interlocking of its particles. Characterized by particle size, particle shape and elasticity behaviors.
Wall friction: Measured as a function of consolidating pressure in accordance with ASTM Standard D 6128. Information obtained from this test is used to determine critical hopper angles for achieving mass flow. The wall material of construction and surface finish must match what will be used for design or analysis purposes.
Compressibility: Measures the change in its bulk density as a function of consolidating pressure. Used to determine storage capacity of equipment and to calculate material-induced material induced loads; measured in accordance with ASTM Standard D 6683.
Permeability: Measure of material resistance to gas flow through it, particularly important when material contains a significant portion of fines. Data obtained is used to calculate the critical, steady-state, flow rate of the material that can occur during discharge as a function of outlet size and consolidating pressure.
Chute angle: Determines the minimum (shallowest) required chute angle to maintain flow after impact of a material stream with its surface. Angles are measured as a function of impact pressure.
Angle of repose and drawdown angle: Measured to help determine the total and live storage capacities of a
can be used in this regard. Additionally, for gravity discharge systems where mass flow is required, the hopper angles must be steep enough to promote flow along the walls. Material handling is a key component to successful biomass cofiring. Technology is available for analyzing storage and handling systems to eliminate or minimize flow problems in existing facilities, as well as for designing new installations to avoid such problems in the first place. Flow property test data is a key component in the process, as it will ensure the reliable storage and flow of biomass materials.
system; these tests provide no further insight regarding material flowability for design purposes.
ous types of configurations available for mechanical reclaim systems, such as a flat bottom silo with a rotating screw or sweep arm reclaimer, a revolving screw reclaimer within a conical bottom silo, a flat bottom silo with a top screw reclaimer, etc. Using flow property test results, the right type of mechanism can be selected so that the sys-
tem is not over- or under-designed for the application. The test results can also aid in the design of mechanism features. The storage system should be designed so as to minimize the consolidation pressures acting on the feeder or reclaimer. The compressibility and wall friction information obtained from flow properties testing
Authors: Jayant Khambekar Project engineer, Jenike & Johanson Inc. jayant@jenike.com, (978) 649-3300 Roger A. Barnum Senior consultant, Jenike & Johanson Inc. rbarnum@jenike.com, 978-649-3300
KAHL Wood Pelleting Plants
Quality worldwide. AMANDUS KAHL USA Corporation · 380 Winkler Drive, Suite 400, Alpharetta · GA 30004-0736 Phone: 770-521-1021 · Fax: 770-521-1022 · sales@amanduskahlusa.com AMANDUS KAHL GmbH & Co. KG · SARJ Equipment Corp., Mr. Rick B. MacArthur · 29 Golfview Blvd., Bradford, Ontario L3Z 2A6 Phone: 001-905-778-0073 · Fax: 001-905-778-9613 · rbmacarthur@sympatico.ca · www.akahl.us