Effectiveness of a densification process to create strong and durable bonding in densified
products such as pellets, briquettes, and cubes can be determined by testing the strength
(i.e., compressive resistance, impact resistance, and water resistance), and durability (i.e.,
abrasion resistance) of the densified products. These tests can indicate the maximum
force/stress that the densified products can withstand, and the amount of fines produced
during handling, transportation, and storage. In this article, the procedures used for
measuring the strength and durability of the densified products are discussed. The effects
of constituents of the feed such as starch, protein, fiber, fat, lignin and extractives; feed
moisture content; feed particle size and its distribution; feed conditioning temperature/
preheating of feed; added binders; and densification equipment variables (forming pressure,
and pellet mill and roll press variables) on the strength and durability of the densified
products are reviewed. This article will help select process parameters to produce strong
and durable densified products from new biomass feedstocks or animal feed formulations.
Guidelines for developing standards on criteria for the acceptance levels of strength and
durability of the densified products are presented.
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