6P65 6P66 PLASCONTM - A THERMAL PLASMA PROCESS FOR DESTRUCTION OF HALON 1211 A J D Farmer CSIRO Division of Telecommunications & Industrial Physics P 0 Box 218, Lindfield NSW 2070, Australia The international recommendations forming the “Montreal Protocol” (agreed to in 1987 and updated several times since) essentially prohibit the manufacture and use of Ozone Depleting Substances (ODS) by signatory countries. Despite this prohibition, a significant problem remains - what do we do with the existing ODS stockpiles? Following the Montreal recommendations, the Australian government decided to target the ODS Halon 121 1 (Bromo- Chloro-diFluoro Methane or BCF - a widely used fire extinguisher), and established its “Halon Bank” to collect the material from industry. The stockpile of BCF in Australia is estimated to exceed 4000 tonnes and approximately 1000 tonnes of this has already been collected by the Federal Government Department of Administrative Services Centre for Environmental Management (DASCEM). Meanwhile, the Australian government research organisation, CSIRO, has been collaborating with an industrial partner, Siddons Ramset Limited Plasma ( S U P ) , in the development of a thermal plasma reactor for BCF destruction purposes. Recently, DASCEM has established a commercial facility for BCF destruction in Australia based on the PLASCONTM process developed by CSIRO and SRLP. The core of the PLASCON reactor is a dc plasma torch operating with argon as the plasma gas. The feedstock is injected at the exit of the torch and the hot gases then flow into a reaction chamber before being quenched and scrubbed with an appropriate liquid. In the case of BCF, destruction efficiencies exceeding the required 99.99% are readily achieved at commercially acceptable feed rates. ATMOSPHERIC PRESSURE PLASMA JET APPLICATIONS J. Park, H. W. Herrmann, I. Henins, and G. S. Selwyn Los Alamos National Laboratory Los Alamos, NM 87545 The atmospheric pressure plasma jet (APPJ) is a non-thermal, high pressure plasma discharge that produces a high velocity effluent stream of highly reactive chemical species. The discharge operates on a feedstock gas (e.g. He/02/H20) which flows between two concentric cylindrical electrodes: an outer grounded electrode and an inner electrode powered at 13.56 MHz W. While passing through the plasma, the feedgas becomes excited, ionized or dissociated by electron impact. The fast-flowing effluent consists of ions and electrons, which are rapidly lost by recombination, highly reactive radicals (e.g. 0, OH), and metastable species (e.g. 02*). The metastable 02, which is reactive to hydrocarbon and other organic species, has been observed through optical emission spectroscopy to decrease by a factor of 2 from the APPJ nozzle exit to a distance of 10 cm. Unreacted metastable 0 2 , and that which does not impinge on a surface, will then decay back to ordinary ground state 02, resulting in a completely “dry”, environmentally- benign form of surface cleaning. Applications such as removal of photoresist, oxide films and organic residues from wafers for the electronics industry, decontamination of civilian and military areas and personnel exposed to chemical or biological warfare agents, and paint (e.g. graffiti) removal are being considered. * This work is supported by the U. S. Department of Energy. The presentation will include a description of the plasma reactor, a discussion of the critical scientific issues considered in the development process and some comments relating to commercialisation. 290

[IEEE 25th International Conference on Plasma Sciences - Raleigh, NC, USA (1-4 June 1998)] 25th Anniversary, IEEE Conference Record - Abstracts. 1998 IEEE International Conference

Download PDF Report

Upload
ajd
View
214
Download
1

Embed Size (px)

Citation preview

Page 1: [IEEE 25th International Conference on Plasma Sciences - Raleigh, NC, USA (1-4 June 1998)] 25th Anniversary, IEEE Conference Record - Abstracts. 1998 IEEE International Conference

6P65 6P66

PLASCONTM - A THERMAL PLASMA PROCESS FOR DESTRUCTION OF HALON 1211

A J D Farmer

CSIRO Division of Telecommunications & Industrial Physics P 0 Box 218, Lindfield NSW 2070, Australia

The international recommendations forming the “Montreal Protocol” (agreed to in 1987 and updated several times since) essentially prohibit the manufacture and use of Ozone Depleting Substances (ODS) by signatory countries. Despite this prohibition, a significant problem remains - what do we do with the existing ODS stockpiles?

Following the Montreal recommendations, the Australian government decided to target the ODS Halon 121 1 (Bromo- Chloro-diFluoro Methane or BCF - a widely used fire extinguisher), and established its “Halon Bank” to collect the material from industry. The stockpile of BCF in Australia is estimated to exceed 4000 tonnes and approximately 1000 tonnes of this has already been collected by the Federal Government Department of Administrative Services Centre for Environmental Management (DASCEM). Meanwhile, the Australian government research organisation, CSIRO, has been collaborating with an industrial partner, Siddons Ramset Limited Plasma (SUP) , in the development of a thermal plasma reactor for BCF destruction purposes. Recently, DASCEM has established a commercial facility for BCF destruction in Australia based on the PLASCONTM process developed by CSIRO and SRLP.

The core of the PLASCON reactor is a dc plasma torch operating with argon as the plasma gas. The feedstock is injected at the exit of the torch and the hot gases then flow into a reaction chamber before being quenched and scrubbed with an appropriate liquid. In the case of BCF, destruction efficiencies exceeding the required 99.99% are readily achieved at commercially acceptable feed rates.

ATMOSPHERIC PRESSURE PLASMA JET APPLICATIONS

J. Park, H. W. Herrmann, I. Henins, and G. S. Selwyn Los Alamos National Laboratory

Los Alamos, NM 87545

The atmospheric pressure plasma jet (APPJ) is a non-thermal, high pressure plasma discharge that produces a high velocity effluent stream of highly reactive chemical species. The discharge operates on a feedstock gas (e.g. He/02/H20) which flows between two concentric cylindrical electrodes: an outer grounded electrode and an inner electrode powered at 13.56 MHz W. While passing through the plasma, the feedgas becomes excited, ionized or dissociated by electron impact. The fast-flowing effluent consists of ions and electrons, which are rapidly lost by recombination, highly reactive radicals (e.g. 0, OH), and metastable species (e.g. 02*). The metastable 02 , which is reactive to hydrocarbon and other organic species, has been observed through optical emission spectroscopy to decrease by a factor of 2 from the APPJ nozzle exit to a distance of 10 cm. Unreacted metastable 02 , and that which does not impinge on a surface, will then decay back to ordinary ground state 02 , resulting in a completely “dry”, environmentally- benign form of surface cleaning. Applications such as removal of photoresist, oxide films and organic residues from wafers for the electronics industry, decontamination of civilian and military areas and personnel exposed to chemical or biological warfare agents, and paint (e.g. graffiti) removal are being considered.

* This work is supported by the U. S. Department of Energy.

The presentation will include a description of the plasma reactor, a discussion of the critical scientific issues considered in the development process and some comments relating to commercialisation.

290