Conversion of a CFCs, HFCs and HCFCs waste mixture via reaction with methane

Han, Wenfeng; Kennedy, Eric M.; Mackie, John C.; Dlugogorski, Bogdan Z.

doi:10.1016/j.jhazmat.2010.08.095

Cited by 7 publications

(3 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hydrogen-containing chlorofluorocarbons (HCFCs) were widely used to prepare the polystyrene (PS) foam in the past 40 years. [1][2][3][4][5][6] However, high values of ozone depletion potential (ODP) and global warming potential (GWP) of HCFCs resulted in a series of environment and climatic problems. 7 Owing to this, HCFCs will be phased out in many countries.…”

Section: Introductionmentioning

confidence: 99%

Complex cellular structure evolution of polystyrene/poly (ethylene terephthalate glycol-modified) foam using a two-step depressurization batch foaming process

Wang

Liu

et al. 2016

Journal of Cellular Plastics

View full text Add to dashboard Cite

In order to decrease the cell size and maintain very high volume expansion ratio simultaneously, a methodology for the preparation of complex cellular structure (CCS) in polystyrene/poly(ethylene terephthalate glycol-modified) (PS/PETG) blend using two-step depressurization pressure batch foaming process was proposed. First, the optimum foaming temperature for PS and PS/PETG blend, respectively, were confirmed by one-step depressurization foaming process. Then, the CCS in PS and PS/PETG blending foam were fabricated by two-step depressurization foaming process at the optimum foaming temperature. The rheological properties of PS and PS/PETG blend were tested by dynamic rotational rheometer. The dispersion morphologies and foam morphologies were observed by scanning electron microscope. The lowest densities of PS and PS/PETG blending foams were obtained at the temperature of 136℃. The interfaces between PS and PETG could act as nucleation sites for the cell nucleation, which were helpful to fabricate the CCS. The CCS could be controlled by tuning the degree of the first-step depressurization and the holding time. The results showed that the large cells could be beneficial to decrease the foam density and the presence of small cells was beneficial to increase the cell number.

show abstract

Section: Introductionmentioning

confidence: 99%

Complex cellular structure evolution of polystyrene/poly (ethylene terephthalate glycol-modified) foam using a two-step depressurization batch foaming process

Wang

Liu

et al. 2016

Journal of Cellular Plastics

View full text Add to dashboard Cite

show abstract

“…For example, in the U.S., the EPA banned the use of HFC-134a (1,1,1,2-tetrafluoroethane, CH 2 FCF 3 ) in 2021 for the manufacture of light-duty vehicles . In the transitioning phase to HFO-based refrigerants, HFCs will be repurposed to create other chemicals or materials (e.g., conversion into vinylidene fluoride for polymer manufacturing) or destroyed by incineration while HFOs will be recycled and reused. At the present time, HFCs are recycled with high purity to remove common impurities such as air, water, oil, and refrigerants that do not form azeotropes, so that the HFCs can reenter the market.…”

Section: Introductionmentioning

confidence: 99%

Azeotropic Refrigerant Mixture R-513A Separation Using Extractive Distillation with Ionic Liquids Entrainers

Arishi,

Shiflett

2023

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

Hydrofluoroolefins (HFOs) are the next generation of refrigerants that have significantly lower global warming potential (GWP) and zero ozone-depleting potential (ODP) and will function as a replacement for hydrofluorocarbons (HFCs). During the transition to HFO refrigerants, a blend of HFC and HFO will be used to reduce the GWP and provide thermophysical properties that are suitable for use in replacing HFCs in existing equipment that may not be compatible or operating with the same performance with only HFOs. The formation of azeotropes in HFC/HFO blends poses a challenge when recycling and reclaiming the refrigerant. To address the problem of azeotropic mixture separation, a highly efficient separation method is required. Extractive distillation using an ionic liquid (IL) as an entrainer is proposed, offering effective separation of azeotropic mixtures. The effectiveness of ILs as an entrainer was determined by selectivity and high affinity toward one or more components of the mixture. The proper selection of the IL as an entrainer for a particular gas mixture is dictated by the purity of the products and the energy and cost of separation. Nine ILs were individually simulated in an equilibrium-based model to separate R-513A using ASPEN Plus to compare the impact of solvent choice on the separation cost. The ILs exhibited variations in overall heat duties, number of stages (N T), operating pressure (P), solvent to feed ratio (S/F), and reflux ratio (RR). The best entrainer option for the separation of R-513A was found to be 1-ethyl-3-methylimidazolium acetate.

show abstract

“…In particular, about 90% of the total atmospheric ozone lies in the stratosphere, which is the major source of blocking the harmful UV radiation to reach in the earth's surface (Struijs et al, 2010). The impact of thinning ozone layer caused by chlorouorocarbons (CFCs) on human health and environment is now globally recognized (Han, Kennedy, Mackie, & Dlugogorski, 2010;Struijs et al, 2010); negative effects of increased UV exposure include skin cancer and cataracts to humans, and irreversible damages to plants and drifting organisms (e.g. animals, plants, archaea, bacteria) in the ocean's photic-zone (Khan, Chiu, & Dubin, 2009).…”

Section: Introductionmentioning

confidence: 99%

A Statistical Investigation to Monitor and Understand Atmospheric CFC Decline with the Spatial-longitudinal Bent-cable Model

Khan¹,

Rana²,

Li³

et al. 2012

IJSP

View full text Add to dashboard Cite

Concerns about the concentrations of chlorofluorocarbons (CFCs) in the atmosphere are based on their effects on the ozone layer by catalytically destroying ozone. The recent steady decline in atmospheric concentration of CFC could be a direct result of the Montréal Protocol's ban on CFC products, in effect since 1989. However, CFCs have long atmospheric residence times because of their low chemical reactivity, and as a consequence have already been distributed globally. To study the spatial effects and extent of the decline, we apply the proposed spatial-longitudinal bent-cable model to CFC data observed over a global detection network. The bent cable is a parametric regression model to study data that exhibits a trend change. It comprises two linear segments to describe the incoming and the outgoing phases, joined by a quadratic bend to model the transition period. For spatial longitudinal data, measurements taken over time are nested within spatially dependent locations. Here, it is useful to extend the existing longitudinal bent-cable regression to handle spatial effects. We do so in a hierarchical Bayesian framework by allowing the error terms to be correlated across space. The methodology is illustrated with applications to CFC-11 and 12 data. Our analysis reveals that: (a) there is a strong spatial relationship among all the monitoring locations across the globe; (b) both CFC-11 and CFC-12 increased significantly before entering into a transition zone; (c) after completing the transition, CFC-11 has been decreasing significantly from the atmosphere, but a slow (insignificant) decrease for CFC-12 is observed; and (d) it may take almost 5 times longer to diminish CFC-12 from the atmosphere compared to CFC-11.

show abstract

Conversion of a CFCs, HFCs and HCFCs waste mixture via reaction with methane

Cited by 7 publications

References 35 publications

Complex cellular structure evolution of polystyrene/poly (ethylene terephthalate glycol-modified) foam using a two-step depressurization batch foaming process

Complex cellular structure evolution of polystyrene/poly (ethylene terephthalate glycol-modified) foam using a two-step depressurization batch foaming process

Azeotropic Refrigerant Mixture R-513A Separation Using Extractive Distillation with Ionic Liquids Entrainers

A Statistical Investigation to Monitor and Understand Atmospheric CFC Decline with the Spatial-longitudinal Bent-cable Model

Contact Info

Product

Resources

About