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Solid Waste Disposal and Land Pollution
News Release from: RAL: Quality Assurance Association | Subject: Hydrocarbon refrigeration
Edited by the Processingtalk Editorial
Team on 01 July 2008
Study sheds light on hydrocarbon
refrigeration
A discussion paper on hydrocarbon refrigeration appliances from Christopher Becker of the RAL Quality Assurance Association for the Demanufacture of Refrigeration Equipment
A recently published study has cast new light on the treatment of end-of-life refrigeration appliances containing hydrocarbons The results of the field study conducted by the Austrian research institute FHA and commissioned by the Federal Ministry of Agriculture, Forestry, Environment and Water Management in Vienna and the RAL Quality Assurance Association for the Demanufacture of Refrigeration Equipment support the approach taken by the Austrian authorities in dealing with waste refrigeration equipment
This article was originally published on Processingtalk on 8 Jul 2008 at 8.00am (UK)
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The tests performed on the recycling plant operated by AVE Osterreich at its Timelkam site generated valuable data on the processing of waste refrigeration appliances containing hydrocarbons ('HC appliances').
The study also includes a forecast of how the fraction of HC appliances in the waste stream will grow over the coming years.
While discussions continue regarding the treatment of end-of-life refrigeration appliances containing CFCs and so-called CFC-free appliances, a number of players in the European recycling industry have acted to establish what is de facto best practice in this field.
Further reading
Sorting errors in waste fridge disposal
The majority of European fridge recycling companies still attempt to sort waste refrigeration appliances into those containing CFCs and those that are CFC-free
New version of GZ-728 standard on fridge recycling
The RAL GZ-728 quality assurance and test specifications to be met when processing end-of-life refrigeration equipment containing CFCs have recently been subjected to comprehensive review and revision
"What should we do with that old fridge?"
In July, the German public television network ARD broadcast a detailed report on fridge recycling in its magazine programme PlusMinus
In many recycling companies it is now standard practice that the fridge recycling plants originally designed to treat CFC appliances and to collect the climatically hazardous CFCs are being used for the joint processing of all waste types of waste refrigeration appliances.
The prior sorting of appliances and the separate treatment of CFC-containing and HC-containing appliances is carried out only at those older plants that no longer employ state-of-the-art fridge recycling technology.
Last year, the large-scale fridge recycling plant in Timelkam (near Salzburg) established the joint processing of CFC and HC appliances as its standard method of treatment in accordance with the requirements of the Austrian Waste Treatment Obligation Ordinance (Abfallbehandlungspflichten-Verordnung).
After switching to joint processing, a number of questions arose that the FHA study was designed to answer.
The FHA study was conducted in close collaboration with the Institute for Statistics and Probability Theory at Vienna Technical University.
The statistical analysis of the data was performed by Professor Klaus Felsenstein.
The primary question addressed in the study was one that previously had not received any systematic analysis: What quantities of hydrocarbons can be recovered from waste HC appliances when processed in state-of-the-art fridge recycling plants? The study also aimed to compare batch processing and joint processing modes and to determine how the CFC and HC recovery rates achieved in joint processing compare with those in batch processing.
In order to generate data on the amounts of hydrocarbons recovered during processing, the plant was run for several days in pure HC batch mode, i.e only HC-containing appliances were processed.
Three different mass balance analyses of the batch processing of HC appliances were carried out.
The three tests were performed on appliances containing HC blowing agents.
The tests on appliance types 1 and 2 each involved 1000 appliances, while 300 appliances were used in the test performed with type 3 appliances.
The HC appliances were categorised in accordance with the standard international definitions.
Once the tests of batch processing had been completed, three tests were conducted to examine the joint processing of CFC and HC appliances.
Each test was performed on 1000 sample appliances.
In test 1, 15 % of the sample appliances contained a hydrocarbon blowing agent, in tests 2 and 3, the proportion of appliances with a hydrocarbon blowing agent was raised to 30 % and 50 % respectively.
The ratio of CFC to HC appliances in test 1 corresponds approximately to the composition of the waste refrigeration equipment currently being sent for treatment.
Tests 2 and 3 aimed to simulate the composition of this waste input stream in the coming years.
The aim of these three tests was to assess whether the CFC and HC recovery rates achieved by the joint processing of CFC and HC appliances were better than, worse than or the same as those achieved in batch processing.
To carry out this assessment, data was also drawn from previous studies of the treatment of CFC appliances and from the tests on the batch processing of HC appliances that were performed as part of the present study.
The field testing was completed in March of this year.
The data indicate not only that joint processing of waste refrigeration equipment in stage II3 of the fridge recycling process is environmentally preferable to batch processing, they also yield some very interesting findings concerning stage I4 treatment as well.
Stage II processing.
Statistically established and reliable data concerning the quantities of CFCs contained in the different types of refrigerator appliances have been available for some time, but until the FHA study was published this information was not available for hydrocarbon appliances.
The tests carried out in batch mode showed that stage II processing recovers on average 130 grams of hydrocarbon blowing agent from a type 1 appliance, 230 g of HC from a type 2 appliance and 340 g of HC from a type 3 appliance.
These values are statistically reliable.
An interesting but worrying fact, however, is that in addition to cyclopentane, the hydrocarbons recovered were found to contain around 20% of other volatile organic compounds.
The fraction of the CFC R141b was particular high.
As analyses of the hydrocarbon-blown insulating foams fed into the recycling plant showed no evidence of CFCs, the question arises as to how the hydrocarbons retrieved became contaminated with CFCs.
As the plant was fed purely hydrocarbon-containing appliances in the period prior to the tests, it is relatively unlikely that these CFCs were residues still present in the plant from when it had been last used for the joint processing of HC and CFC appliances.
By preparing the plant in this way, it was hoped that any residual CFCs would be 'flushed' out of the plant separation and collection systems.
As the fraction of these other volatile organics was essentially constant in each of the three batch mode tests, it seems unlikely that CFCs were being retained long-term in the plant active carbon filter cartridges, because one would have then expected the fraction of CFCs found to have been less in the later tests.
The tests carried out in joint processing mode confirm the data acquired in the batch mode tests.
As already mentioned, analysis of the results of the tests carried out in batch mode yielded the average amounts of hydrocarbons contained in each of the three appliance types.
When combined with the equivalent data already available for CFCs, the expectation values for the three tests carried out in joint processing mode could be calculated based on the relevant ratio of HC to CFC appliances used.
In all three tests of the joint processing of HC and CFC appliances, the actual quantities of blowing agents recovered were greater than the calculated expectation values.
The results clearly refute any suggestions that the recovery of hydrocarbons would adversely affect the recovery of CFCs.
Stage I processing.
This series of tests were analogous to the internationally applied '100 appliance tests' used to examine the efficiency with which CFC refrigerants are recovered from the appliance's cooling circuit ('stage I processing').
As this test is based on the vacuum extraction of the refrigerant from one hundred undamaged appliances, it is essential that undamaged appliances and defective appliances can be clearly distinguished.
In the case of CFC appliances, an appliance is generally deemed to be defective if the pressure in the cooling circuit is measured to be 0.2 bar or less.
However, in the tests performed in Timelkam, it was found that the pressure in the cooling circuit of the HC appliances was very often around 0.2 bar or less.
The question whether HC appliances tend to lose refrigerant from their cooling circuits much earlier than CFC appliances, or whether the pressure in the cooling circuit of an HC appliance is inherently much lower than that in a CFC appliance remains unresolved at present.
As a result, the conclusions drawn from a '100 appliance test' of HC appliances are not so clear cut as those from tests involving one hundred CFC appliances.
Sorting errors arising when HC and CFC appliances are separated.
An interesting 'by-product' of the FHA study was the information it provided concerning the missorting of appliances at the recycling plant.
Even when the CFC and HC appliances were sorted and separated by qualified members of the AVE workforce, around 1.6% of the incoming appliances were incorrectly sorted.
This figure confirms the sorting error rate of 1% that was assumed in the life cycle assessment study published by the Oko-Institut e.V in 2007.
Forecast of the fraction of HC appliances in the waste stream in coming years.
A further important part of the study was the rigorous computation of the relative proportions of CFC and HC appliances in the waste refrigeration equipment sent for treatment in future.
None of the estimates available up until now were reliable in a statistical sense.
However, the FHA in collaboration with the Institute for Statistics and Probability Theory at Vienna Technical University has now been able to generate unambiguous data.
It is immediately apparent that the need to have plants capable of recovering CFCs from waste refrigeration equipment will remain until well past the year 2020.
According to the analysis in the FHA study, it will be around 2014 before recyclers see about 50 % CFC appliances and 50 % HC appliances.
The FHA study clearly shows that the proportion of HC appliances in the waste stream is not growing at anything like the rate assumed up until now.
As a result, the need for environmentally sound processing of waste refrigeration appliances containing CFCs will remain with us for many more years.
The study also provides the data required for any future computation of expected recovery rates in the joint processing of CFC and HC appliances.
The fact that the hydrocarbons recovered during the batch processing of supposedly pure HC appliances contain around 20 % CFCs and other volatile hydrocarbon derivatives is another reason why HC appliances and CFC appliances must not be treated separately.
The sorting error rates established in the FHA study are another compelling argument for the joint processing of CFC and HC appliances.
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