Under simulated atmospheric condition, photoomdation for HCFC-22 + H2O2, HCFC-22 + H2O2+O2, HFC-134A + H2O2 and HFC-134A + H2O2+ O2 systems were studied.H2O2 was irradiated by low pressure mercury lamp and produced OH...Under simulated atmospheric condition, photoomdation for HCFC-22 + H2O2, HCFC-22 + H2O2+O2, HFC-134A + H2O2 and HFC-134A + H2O2+ O2 systems were studied.H2O2 was irradiated by low pressure mercury lamp and produced OH radicals. The OH radicals can initiate photooxidation of HCFC-22 and 134A. The products of photooxidation were determined by a Fourier Transform infrared Spectroscopy with a 20ml long path cell. The products were COF2,CO2, HCI, H2O and HF for HCFC-22 + H2O2 system, HO, CO2, HCI and HF for HCFC-22 +H2O2 +O2 system, HCOF, CF3OOCF3,CO2, H2O and HF for HFC-134A +H2O2 system, HCOF, CO2, H2O, and HF for HFC-134A + H2O2+ O2 system. Based on those results, the mechanisms of photooxidation were suggested.展开更多
1 INTRODUCTIONHydrochlorofluorocarbons(HCFCs)and hydrofluorocarbons(HFCs)are alternatives tochlorofluorocarbons(CFCs),such as CFC12(freon 12),which has been widely used asan aerosol agent and working fluid of domestic...1 INTRODUCTIONHydrochlorofluorocarbons(HCFCs)and hydrofluorocarbons(HFCs)are alternatives tochlorofluorocarbons(CFCs),such as CFC12(freon 12),which has been widely used asan aerosol agent and working fluid of domestic1:ICthdflC(CHCIFZ,HCFC22,R22)is one of the potential alternatives.It Is also one of the po-tentlal entralner for supercrltlcal fluid CO,extraction.展开更多
Climate change and ozone depletion are topics challenging the world over and are both attributed mainly to human activities,particularly emissions of ozone depleting substances.One such substance is chlorodifluorometh...Climate change and ozone depletion are topics challenging the world over and are both attributed mainly to human activities,particularly emissions of ozone depleting substances.One such substance is chlorodifluoromethane(HCFC-22),a cheap,widely used refrigerant with a high global warming potential and a chemical target for phase-out under the Montreal protocol.Botswana like all signatory countries to the Montreal Protocol is required to develop and implement a country-level Hydrochlorofluorocarbon Phase-out Management Plan(HPMP).This study focused on evaluating the environmental and socioeconomic implications of phasing out HCFC-22 in Botswana.A census of nine HCFC-22-importing companies was conducted and probability sampling proportional to company size was used to select a sample of 159 respondents from the Department of Meteorological Services,Customs officers and HCFC-22 Industrial consumers.Annual HCFC-22 importation figures for Botswana in 2009-2017 from the National Ozone Unit were analysed.It emerged that HCFC-22 phase-out had reduced HCFC-22 consumption by approximately 510,400 kg in 2011-2017,translating to 28,072 ozone depleting potential(ODP)saved.Also,the HCFC-22 phase-out plan saved the country 128 kW h of electricity for 2009-2017.While decreasing demand for HCFC-22,the HPMP had correspondingly occasioned the higher replacement and servicing costs of HCFC-22-compliant equipment,as HCFC-22 substitutes cost more.To deter use of HCFC-22 and promote phase-out,the price of substitute refrigerants can be made less expensive than HCFC-22.Participating stakeholders attest that HCFC-22 phase-out has positive social benefits such as raising community awareness of the ozone depleting phase-out.As a recommendation,the government of Botswana could offer a number of incentives towards HCFC-22 substitutes uptake in order to give impetus to technology transfer.展开更多
文摘Under simulated atmospheric condition, photoomdation for HCFC-22 + H2O2, HCFC-22 + H2O2+O2, HFC-134A + H2O2 and HFC-134A + H2O2+ O2 systems were studied.H2O2 was irradiated by low pressure mercury lamp and produced OH radicals. The OH radicals can initiate photooxidation of HCFC-22 and 134A. The products of photooxidation were determined by a Fourier Transform infrared Spectroscopy with a 20ml long path cell. The products were COF2,CO2, HCI, H2O and HF for HCFC-22 + H2O2 system, HO, CO2, HCI and HF for HCFC-22 +H2O2 +O2 system, HCOF, CF3OOCF3,CO2, H2O and HF for HFC-134A +H2O2 system, HCOF, CO2, H2O, and HF for HFC-134A + H2O2+ O2 system. Based on those results, the mechanisms of photooxidation were suggested.
文摘1 INTRODUCTIONHydrochlorofluorocarbons(HCFCs)and hydrofluorocarbons(HFCs)are alternatives tochlorofluorocarbons(CFCs),such as CFC12(freon 12),which has been widely used asan aerosol agent and working fluid of domestic1:ICthdflC(CHCIFZ,HCFC22,R22)is one of the potential alternatives.It Is also one of the po-tentlal entralner for supercrltlcal fluid CO,extraction.
文摘Climate change and ozone depletion are topics challenging the world over and are both attributed mainly to human activities,particularly emissions of ozone depleting substances.One such substance is chlorodifluoromethane(HCFC-22),a cheap,widely used refrigerant with a high global warming potential and a chemical target for phase-out under the Montreal protocol.Botswana like all signatory countries to the Montreal Protocol is required to develop and implement a country-level Hydrochlorofluorocarbon Phase-out Management Plan(HPMP).This study focused on evaluating the environmental and socioeconomic implications of phasing out HCFC-22 in Botswana.A census of nine HCFC-22-importing companies was conducted and probability sampling proportional to company size was used to select a sample of 159 respondents from the Department of Meteorological Services,Customs officers and HCFC-22 Industrial consumers.Annual HCFC-22 importation figures for Botswana in 2009-2017 from the National Ozone Unit were analysed.It emerged that HCFC-22 phase-out had reduced HCFC-22 consumption by approximately 510,400 kg in 2011-2017,translating to 28,072 ozone depleting potential(ODP)saved.Also,the HCFC-22 phase-out plan saved the country 128 kW h of electricity for 2009-2017.While decreasing demand for HCFC-22,the HPMP had correspondingly occasioned the higher replacement and servicing costs of HCFC-22-compliant equipment,as HCFC-22 substitutes cost more.To deter use of HCFC-22 and promote phase-out,the price of substitute refrigerants can be made less expensive than HCFC-22.Participating stakeholders attest that HCFC-22 phase-out has positive social benefits such as raising community awareness of the ozone depleting phase-out.As a recommendation,the government of Botswana could offer a number of incentives towards HCFC-22 substitutes uptake in order to give impetus to technology transfer.
