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Dive into the research topics where Helena L. Chum is active.

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Featured researches published by Helena L. Chum.


Environment International | 1995

Controlled catalytic and thermal sequential pyrolysis and hydrolysis of mixed polymer waste streams to sequentially recover monomers or other high value products

Robert J. Evans; Helena L. Chum

A process of using fast pyrolysis in a carrier gas to convert a plastic waste feedstream having a mixed polymeric composition in a manner such that pyrolysis of a given polymer to its high value monomeric constituent occurs prior to pyrolysis of other plastic components therein comprising: selecting a first temperature program range to cause pyrolysis of said given polymer to its high value monomeric constituent prior to a temperature range that causes pyrolysis of other plastic components; selecting a catalyst and support for treating said feed streams with said catalyst to effect acid or base catalyzed reaction pathways to maximize yield or enhance separation of said high value monomeric constituent in said temperature program range; differentially heating said feed stream at a heat rate within the first temperature program range to provide differential pyrolysis for selective recovery of optimum quantities of the high value monomeric constituent prior to pyrolysis of other plastic components; separating the high value monomeric constituents; selecting a second higher temperature range to cause pyrolysis of a different high value monomeric constituent of said plastic waste and differentially heating the feedstream at the higher temperature program range to cause pyrolysis of the different high value monomeric constituent; and separating the different high value monomeric constituent.


Environment International | 1995

Controlled catalytic and thermal sequential pyrolysis and hydrolysis of polymer waste comprising nylon 6 and a polyolefin or mixtures of polyolefins to sequentially recover monomers or other high value products

Robert J. Evans; Helena L. Chum

A process of using fast pyrolysis in a carrier gas to convert a plastic waste feedstream having a mixed polymeric composition in a manner such that pyrolysis of a given polymer to its high value monomeric constituent occurs prior to pyrolysis of other plastic components therein comprising: selecting a first temperature program range to cause pyrolysis of said given polymer to its high value monomeric constituent prior to a temperature range that causes pyrolysis of other plastic components; selecting a catalyst and support for treating said feed streams with said catalyst to effect acid or base catalyzed reaction pathways to maximize yield or enhance separation of said high value monomeric constituent in said temperature program range; differentially heating said feed stream at a heat rate within the first temperature program range to provide differential pyrolysis for selective recovery of optimum quantities of the high value monomeric constituent prior to pyrolysis of other plastic components; separating the high value monomeric constituents; selecting a second higher temperature range to cause pyrolysis of a different high value monomeric constituent of said plastic waste and differentially heating the feedstream at the higher temperature program range to cause pyrolysis of the different high value monomeric constituent; and separating the different high value monomeric constituent.


Environment International | 1995

Controlled catalystic and thermal sequential pyrolysis and hydrolysis of polycarbonate and plastic waste to recover monomers

Robert J. Evans; Helena L. Chum

A process of using fast pyrolysis to convert a plastic waste feed stream containing polycarbonate and ABS to high value monomeric constituents prior to pyrolysis of other plastic components therein comprising: selecting a first temperature program range to cause pyrolysis of a given polymer to its high value monomeric constituents prior to a temperature range that causes pyrolysis of other plastic components; selecting an acid or base catalysts and an oxide or carbonate support for treating the feed stream to affect acid or base catalyzed reaction pathways to maximize yield or enhance separation of the high value monomeric constituents of polycarbonate and ABS in the first temperature program range; differentially heating the feed stream at a heat rate within the first temperature program range to provide differential pyrolysis for selective recovery of optimum quantities of the high value monomeric constituents prior to pyrolysis or other plastic components; separating the high value monomeric constituents from the polycarbonate to cause pyrolysis to a different high value monomeric constituent of the plastic waste and differentially heating the feed stream at the second higher temperature program range to cause pyrolysis of different high value monomeric constituents; and separating the different high value monomeric constituents.


Archive | 1992

Process to convert biomass and refuse derived fuel to ethers and/or alcohols

James P. Diebold; John W. Scahill; Helena L. Chum; Robert J. Evans; Bahman Rejai; Richard Bain; Ralph P. Overend


Archive | 1988

Process for fractionating fast-pyrolysis oils, and products derived therefrom

Helena L. Chum; Stuart K. Black


Archive | 1989

Supercritical separation process for complex organic mixtures

Helena L. Chum; Giuseppe Filardo


Archive | 1993

Phenolic compounds containing/neutral fractions extract and products derived therefrom from fractionated fast-pyrolysis oils

Helena L. Chum; Stuart K. Black; James P. Diebold; Roland E. Kreibich


Archive | 1992

Process for preparing phenolic formaldehyde resole resin products derived from fractionated fast-pyrolysis oils

Helena L. Chum; Roland E. Kreibich


Archive | 1998

Pyrolysis and hydrolysis of mixed polymer waste comprising polyethyleneterephthalate and polyethylene to sequentially recover

Robert J. Evans; Helena L. Chum


Archive | 1992

Pyrolysis of polystyrene - polyphenylene oxide to recover styrene and useful products

Robert J. Evans; Helena L. Chum

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Gerardo Hiriart

Comisión Federal de Electricidad

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Luis Gutierrez-Negrin

Comisión Federal de Electricidad

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John Nyboer

Simon Fraser University

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Dan Arvizu

National Renewable Energy Laboratory

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