Energy pellet

Abstract

A high-energy water-resistant pellet of at least 75% biomass material such as torrefied wood, whole-tree (white) wood, agricultural waste, flax and the like. and the remainder a binder comprising from about 2% to about 20% by total weight of the pellet. The binder is a two-component system—a plasticizer, such as tall oil pitch, rosin, fatty acid, vegetable oils, animal oils, corn protein and glycerin—preferably from 3% to about 20% of the binder, and lignin from about 80-97% of the binder.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This Application is a continuation in part of application Se. No. 14 / 414,202 filed Jan. 12, 2015, which claims benefit of PCT Application U.S. 2013 / 050679, filed Jul. 16, 2013, which claims benefit of Provisional Application Ser. No. 61 / 673,573 filed Jul. 19, 2012, on which the present Application is based and benefit claimed under 35 U.S.C. §119(e), is herein incorporated by reference.BACKGROUND OF THE INVENTIONField of the Invention[0002]The present invention relates to energy pellets made from biomass material, such as torrefied wood, whole-tree (white) wood, agricultural waste, flax and the like. It also relates to methods of making energy pellets. More particularly, this invention relates to energy pellets made from torrefied wood or white wood combined with lignin and a biomass-based plastizer to form a water-resistant and durable high-energy-density pellet.Description of Related Art[0003]In recent years renewal energy sources have ...

AI Technical Summary

Benefits of technology

The present invention relates to a fuel pellet made from torrefied wood or white wood, or from agricultural waste. The fuel is designed to be high-energy and high-density, and to be water-repellent. Specifically, the patent text describes a fuel pellet made from flax and a two-component binder that is water-repellent. The technical effect is to provide a unique fuel option that is highly efficient and can be easily stored and transported.

Problems solved by technology

However, when a pellet is made from torrefied wood, most of the natural binders are burned off so that the resulting pellet has poor water repellency, and in a worst case, the pellets turn into a black “mud” upon exposure to water.

Another problem with torrefied wood and even with some of the other biomass materials, especially those made from low-resin-containing biomass materials, is durability.

The pellets themselves tend to be friable and create dust during mechanical processes needed to transport the pellets, such as loading and unloading rail cars and ships.

In addition to product loss, the dust creates hazards, from inhalation and the potential for dust explosions.

Currently wood-based energy pellets are burned, but the lower energy density and their pulverizing and burning characteristics limit their use as a fuel since they are so different from coal.

The problem is that isolated solidified lignin is very friable, and its melt point may not be ideal for the pelletizing system so that the lignin melts and flows within the pelletizer but solidifies upon exiting and cooling.

Lignosulfonates are a poor choice as energy pellet binders because: (1) lignosulfonates have high levels of organically-bound sulfur—as high as 10% by mass—that converts to sulfur dioxide upon combustion; and (2) lignosulfonates contain residual sugar from the pulping process.

These sugars are hydrophilic and deleteriously affect the water resistance of energy pellets.

The sulfonate groups on the lignin are also hydrophilic, exacerbating the water resistance problem.