Factors Affecting Strength and Durability of Densified Products

Abstract

Effectiveness of a densification process to create strong and durable bonding in densified productssuch 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 amountof fines produced during handling, transportation, and storage. In this article, the procedures used formeasuring the strength and durability of the densified products are discussed. The effects of constituents of thefeed such as starch, protein, fiber, fat, lignin and extractives; feed moisture content; feed particle size and itsdistribution; feed conditioning temperature/preheating of feed; added binders; and densification equipmentvariables (forming pressure, and pellet mill and roll press variables) on the strength and durability of thedensified products are reviewed. This article will help select process parameters to produce strong and durabledensified products from new biomass feedstocks or animal feed formulations. Guidelines for developingstandards on criteria for the acceptance levels of strength and durability of the densified products arepresented.