Final Report - Ohio Department of Transportation

1. Introduction
The research project described here was designed to explore the basic feasibility of
recovering sufficient bitumen from yard waste carbonization processes to support the
production of bioasphalt. If successful, this could produce a non-petroleum-based product of
value to the transportation industry that results from a “carbon negative” process that sequesters
more CO2 than it releases. The amount of bitumen that can be produced from yard waste, the
physical and chemical properties of this bitumen, the carbonization operating conditions under
which the production of this material is optimized, and a host of other unit process and operation
details are all unknown, but the potential advantages of this yard waste management strategy are
intriguing. The work described here represents groundbreaking research that begins to answer
basic questions about the potential of yard waste carbonization (YWC) to produce a practical
bitumen product that could be used to produce bioasphalt.
The fundamental approach applied in this research is described in Section 1.7. However,
before discussing these project details, it seems prudent to document the context from which the
project emerged. Readers will almost certainly observe that carbonizing yard waste is not an
obvious approach for yard waste management or the production of useful byproducts. It is,
however, plausible and emerged as an option during exploratory research based on a growing
interest in carbonization as a “green” technology. Therefore, the following sections present
some of the background information that led to this project.
1.1 Recent Interest in Carbonization as a “Green” Technology
Processes based on heating an organic substrate in the absence of oxygen (pyrolysis) and the
absence of a bulk liquid phase (anhydrous pyrolysis) predate recorded history. Pyrolysis has
been used to produce primary products (char, charcoal, coke) and byproducts (tar, pitch, resin)
for thousands of years. Modern applications have led to a wide variety of process innovations
(e.g. flash pryrolysis), reactor configurations and target products. Pyrolysis is used to produce
fuels and other liquid and gas phase organics, as an analytical method to analyze complex
organics, and to manage organic wastes (e.g. pyrolysis of scrap tires). However, until recently, its
energy demands and byproduct discharges would probably not have placed it high on the list of
“green” technologies. This is changing because of recent interest in “carbonization” which will
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