Blow your mind
Another lesser-known end use for f-gases - Blast Bags!
Hi Folks,
When I talk to people about f-gases, one of the most common reactions I get is - ‘I had no idea’. Not just referring to their environmental impact, but that they have become so prevalent across so many different applications.
In the last edition I referred to the use of f-gases contained in building insulation foams. In my experience something not particularly well known, especially considering the environmental problems come demolition time or retrofit. You can catch up on that edition here.
This week I’ve got an application that was unknown to me until recently. So let’s jump straight into #wherethefgashides.
Having a blast
We’ve discussed before that the properties of fluorinated gases (especially the HFCs) make them ideal for many applications, aside to being used as refrigerants. Their ‘useful’ properties (i.e. being stable and non-reactive among other things) also contribute to what makes them a problem in the environment.
One somewhat interesting application is within the mining industry. One which makes good use of these properties; in what are commonly referred to as ‘Blast Bags’.
I’m not a mining expert here, but my understanding is that they are used to help control and optimise blasts used in the extraction process, both in underground and surface mining. A common example being where a vertical hole is drilled and filled with explosive, and a blast bag installed in the top of the hole to help retain the explosive force.
The blast bags come flat-packed and are inflated as they are inserted into the hole. There are several ways to inflate the bags, with a common method using an inbuilt aerosol inflator.
Now, why we’re here is that several manufacturers have bags that are inflated using a f-gas aerosol. There are a number of products containing HFC-134a, also a common refrigerant, with a global warming potential (GWP) of 1530.
The argument goes that the explosion heat should decompose the HFC during the blast. However, from what I’ve read this is not always the case, and hence some (or possibly a lot) of it ends up in the atmosphere, where it does its heat trapping work.
I’ve not found any studies to suggest how much makes it to atmosphere. What we do know however is that emissions occur all along the supply chain, from the HFC production, distribution and manufacture. There are fugitive emissions before the bag even makes it into the blast hole.
There are also other applications where blast bags are used in non-explosive roles. Here there is anecdotal evidence to suggest that once used, the bags may be pierced before disposal and the f-gas then released...
Like many applications, there are alternatives to using HFCs such as Dimethyl Ether (DME) and naturally occurring products.
There are some bags that are now using the f-gas HFO-1234ze. Which, while having a lower GWP on paper, has been classed as a PFAS in some countries (persistent chemicals of which many are toxic) as well as the breakdown product TFA (another PFAS).
Aside to leaving behind forever chemicals, there are plenty of other considerations here of course. Given the blast bags are used to enhance the extraction of coal. Add to that, there is the irony that one of the blast bag manufacturers names its product line after endangered animals. Great work there from the marketing department…
Right, that’s all for this week and until next time,
Adrian.
p.s. The title from the last edition – Hide in your shell – was from one of the first albums I ever purchased, by Supertramp. Was a good excuse to give it another spin
Fixed stuff here for newcomers
There is lots of news every week from the cooling industry and plenty of newsletters that cover it well. The intention is to keep this newsletter focused on the most prominent f-gases (fluorinated greenhouse gases), the most common of which are refrigerants and importantly their environmental impact. That’s the lane I’ve chosen - I’ll do my best to stick to it.
The What
Below are the seven formal greenhouse gases that countries and companies should track, report and hopefully reduce.
Carbon Dioxide (CO2)
Methane (CH4)
Nitrous Oxide (N2O)
Hydrofluorocarbons (HFCs)
Perfluorocarbons (PFCs)
Sulphur Hexafluoride (SF6)
Nitrogen trifluoride (NF3)
Plus the still circulating, ozone damaging chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and the ‘new-generation’ hydrofluoroolefins (HFOs).
Hopefully you can spot the pattern.
The Why
Emissions from f-gases and refrigerants have been the fastest growing greenhouse gases over the past decade (more than CO2 and methane - check out IPCC WG3 summary for policy makers). They are also classed as super pollutants given their outsized global warming and other environmental impacts.
You can find my basic primer here and a plenty more detail in the whitepaper here
Some useful permalinks
The scale of the climate challenge can often feel daunting. This piece helps me take a step back and understand where we need to focus first - recommend a read.
There are plenty of technology solutions available to address the cooling and refrigerant challenge. You can find many of them here
Beware when the same entities who have contributed to the current f-gas problem propose you new solutions… This is a good place to get up to speed.