Pyrolysis system to create bio-oil from poultry litter

Posted by Wolfgang Gruener

Boston (MA) – Scientists from Virginia Tech announced that they are developing a portable pyrolysis unit that will create bio oil from poultry litter.

According to Foster Agblevor, associate professor of biological systems engineering at the College of Agriculture and Life at Virginia Tech, more than 5.6 million tons of poultry litter, consisting of bedding, manure, feathers, and spilled feed, are produced each year in the United States. Today, poultry litter is causing huge amounts of potentially dangerous waste, but if Agblevor can translate his vision into reality, the litter could be reduced to char, fertilizer, gas - and valuable bio oil.

The researcher said that currently developed transportable pyrolysis units are designed to
heat the litter until it vaporizes. The vapor is then condensed to produce the bio-oil, and a slow release fertilizer that is recovered from the reactor as well. The remaining gas can then be used to operate the pyrolysis unit, making it a self-sufficient system.

According to Agblevor, bio-oil yields range from 30 to 50% by weight, depending on the age and the bedding content of the litter. Highest yields were achieved with bedding materials such as wood shavings or peanut hulls - up to 62% by weight. However, bio-oil extracted from poultry litter contains more energy (26 to 29 mega joules per kilogram) than from bedding (24 mega joules per kilogram).

On the other side, generated char was between 30 to 50% by weight, with a share of ashes of between 30 and 60% by weight, depending on the age and source of litter.

Pyrolysis has been a common tool in waste management for some time and is based on the idea of the chemical decomposition of organic materials by applying heat. The process leaves carbon as residue.

If Agblevor will actually be able offer transportable pyrolysis units, then farmers may not only be able to get rid of a relatively dangerous source of diseases through what he calls a "clean-burning process", but also create a new revenue source for farmers: Bio-oils are becoming an increasingly valuable energy source and researchers are looking for ways to extract bio oils from more resources than corn. For example, researchers from the University of Georgia recently said they have developed a technology to use wood chips for the generation of bio-fuel.

“The type of poultry litter used will affect the amount and quality of the bio-oil produced and ultimately will impact the producer’s profitability,” Agblevor said in a prepared statement. “Finding the right set of conditions for the poultry litter is key to the adaptation of this technology.”