A BRIGHT LINE for THERMAL PROCESSING:

CONVERSION  vs. INCINERATION

Michael Theroux 

JDMT, Inc

 March 14, 2006

Preface

There is a “combustion chemistry” continuum of thermal processing, from initial drying through oxygen-starved heating and initial phase separation (pyrolysis), through controlled oxygen conversion of solids to gases (gasification) and finally to the endpoint of “thermal oxidation”, or incineration. We can and should interrupt this continuum, to test and (as necessary) clean the intermediary products.

Assessment and management of intermediary products is the “Bright Line” that differentiates Conversion Technologies, or ”CTs”, from Incineration. Instead of allowing thermal conversion to proceed unimpeded to full oxidation, the CT is designed to allow testing and cleaning of the synthetic gases, pyrolytic oils and chars prior to further usage. This makes clean thermal conversion of wastes and by-products to green chemicals, biofuels and renewable energy possible, by establishing the critical information “feedback loop” necessary to manage contaminants before they become emissions.

It is still usually cheaper, at least at first glance, to just dispose of our massive volumes of waste in a landfill, or in an incinerator, rather than convert it back to clean, useful commodities. The real costs of our older options require life-cycle analysis, to identify the significant long-term global negative impacts.

CT development and commercialization now stands between three opposing forces: (a) those that believe that all thermal conversion methods equate to incineration, that any thermal conversion must produce unacceptable quantities of toxic emissions, (b) those that believe total thermal oxidation (incineration) should remain the acceptable practice not to be displaced by “conversion”, and (c) those that believe current landfill collection, disposal and recycling business efforts will be jeopardized by CT development, since the waste they depend upon could become feedstock for conversion.

This “Bright Line” white paper proposes adoption of the following three defensible positions in support of waste conversion to clean energy, fuels and products, as the core of a broad public outreach program for advancement of the conversion technology debate.

(1) Conversion IS NOT Incineration: There is a difference between "dirty" incineration and "clean" conversion, a bright line yet to be clearly defined in laymen’s terms and thus not yet commonly accepted. Incineration is defined as "... to render to ash" (Oxford Dictionary). All thermal waste processing technologies can proceed to complete thermal oxidation, given the right conditions, but to do so will reduce whatever higher grade components might be available to that least common denominator, “ash”, without interjecting value-added extraction or intermediary contaminant management.

According to the authoritative “Pyrolysis & Gasification” report published by Juniper[1], "Conversion" operations MUST enable sampling and (to the degree necessary) cleaning of the intermediary products. All equipment can be run "dirty" or "clean” and almost all thermal processes can be operated to proceed to full thermal oxidation without decontamination of the gases, oils, and solid chars. To operate without such sampling is to operate the technology as an Incinerator.

IF a technology allows intermediary products to be sampled and cleaned, and IF operation of that technology is not allowed to proceed to total "rendering to ash" without appropriate contaminant management, THEN it is a waste processing system operated as a Conversion Technology. This "bright line" is in equal parts a question of the specific technology, and of the method of operation: socio-economic drivers such as economic support and regulatory enforcement MUST be focused upon the total performance, not independently the technology or the method of operation. 

(2) Conversion IS Resource Recovery, Not Disposal: When resources are "rendered to ash" through incineration, it is not possible to return the many critical resource components to productive use in the marketplace, other than simple generation of heat. With Conversion, the molecular components of the waste stream may be segregated, decontaminated, and reconstituted for further commercial use. This constitutes "recycling" at the molecular level.

The cleanliness of the resultant products must be subjected to regulatory and market controls just as stringent as for their virgin commodity complements. This "product quality assurance" then becomes the standard by which a conversion technology must be operated to truly be considered "resource recovery". It is not sufficient to simply produce a "commodity", if that gas, liquid or solid really just constitutes another environmental contaminant awaiting release.

(3) Conversion IS Mitigation: We must continue to adopt the most advanced technologies available to us to replace the functions of older, dirtier technologies and processes currently in use in any one region. With implementation of the cleaner technologies and methods, we can incrementally reduce the regional contaminant burden. We must (a) know the physical air, land and water boundaries of a region, (b) know the background contaminant levels, and (c) know the primary contributors to that contamination that may be replaced.

The EPA recognizes landfilling and waste incineration as among the most significant national sources of air basin contamination. These older waste management processes may be now be replaced at least in part by conversion of the constituents of the waste, decontamination of the intermediary products, and return of clean commodities to the marketplace. By implementing an integrated materials recovery facility (MRF) and conversion technology (CT) program in a way that promotes less environmental and socio-economic cost than landfilling, a region can quantify CT use as an incremental means of air basin emissions mitigation.

This article is copyrighted. You are free to reprint and use it as long as no changes are made to its content or references, and credit is given to the author.

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