Totally understand. But that’s how these standards work. Just trying to help explain. We’re open for suggestions.
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Yes! Pop into the other thread and let’s talk about it! Mystery oil is a tough nut to crack and we’re trying.
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Yeah wut? You run a calibration curve for the compounds you’re testing for. If there are compounds that aren’t quantified but are present, you should totally get a number less than 100%. You don’t compare peak area and say everything that was integrated adds up to 100%, that’s not how quantification by chromatography works
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So when you guys are selling instrument grade gas which you all say has to be 99.5% or above……. What would the other .5% be if your only testing for gas you know is there?? What other gases can be in there other than hydrocarbons??
This is really weird huh guys?
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I’m honestly absolutely speachless.
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So a tank can be 80% water and 20% gas. As long as the tank has c1-c8. It’s gonna show 100% instruments grade.
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We test for over 50 hydrocarbons, sulfur, and oxygenated/chlorinated products. That covers everything associated with the LPG’s we deal with. The point made about 100% recovery just meant that every analysis always adds up to 100% and only includes the components on the identifiable list. That’s why multiple tests are required to really adequately identify EVERYTHING but each individual test equals 100% individually. And yes recovery matters, an acceptable range is ± 2% that way there aren’t gross over/under normalization.
Not expressing my frustration at you, seems like this is across the board. This should be fixed for sure though.
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Completely fine man. My chemist is out for the evening but we can expand the conversation on testing tomorrow and get into greater detail.
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Me neither. I’m just kinda fucking dumbfounded
I guess u learn something new every day. This is gonna be a lot harder now to figure this problem out as it can be anything
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This is disgusting. So a tank can be 50% cyclops tane and we see nothing
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Chest freezer refrigerant
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May be worth splitting this off too if anyone else agrees. From my limited understanding, it’s going to be a long conversation.
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Adam’s right analysis should be on the other thread The GC-FID counts carbon molecules. If the testing is done properly each species will peak at a different retention time. It can detect BTEX molecules because they are hydrocarbons.
But doesn’t see water and can only detect the sulfur molecules with carbon atoms in them. Different testing methods are required
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What testing methods?
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Can we move this to the:
What compounds should be considered impurities in extraction gasses?
Thread
i moved all the posts into this thread… thanks…
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FicklePickleLeader
What testing methods?
We’ve always used manufacturers analysis for moisture and sulfur.
Water testing is rather simple in the vapor phase. Not sure the process for liquid testing, butt it’s probably googable.
Sulfur testing target species would be metal and ethyl mercaptan, CS2, COS and H2S. A sniff test is sufficient to verify manufacturers analysis. We’ve never done a test for all sulfur. I don’t think there’s a need to unless the gas stinks. No?
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Though wouldn’t it be a valid pursuit to work to bridge the knowledge gap between suppliers and customers? As a generality, this community doesn’t seem to have a strong appetite for imposed rules and regulations–regardless of whether they’re a certain eventuality. Wouldn’t it be great to work with the community to develop the standard for extraction? I mean here we sit with an opportunity to influence what those rules and regulations will be. That can help ensure that such regulations:
i) adequately protective of the customers and their consumers; and
ii) not so cost prohibitive on the supply side that legal BHO becomes no longer feasible from a cost perspective.
If we’re all working toward that goal, maybe we can actually get to a point that we can provide our customers a product that better suites their needs and eliminates some of the controversy and disagreement that seems to be rampant on this subject.
Given your long standing relationship with your supplier, I’d assume you’d have some influence over what their standards and practices are. If not, since they’re following along, maybe they can chime in on their willingness to make modifications based on the community’s input and the needs of the customer base? Our supplier has committed to working with us through such a process but we’re a pretty tiny representative share of the gas that’s out there.
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@Killa12345 @johnbigoilco @Dukejohnson
Sorry for the wall of text but I promised a follow up.
I wanted to talk this over with our chemist to get some practical examples of why this would not happen. He shared the following with me:
- If we were to run a sample of a 70/30 nButane/Propane blend through a hypothetical standard that only parsed C4 hydrocarbons, the analysis would yield raw results of 70% nButane. That 70% recovery would be normalized to equal a full 100% recovery such that the final report would be bumped up to 100% despite the presence of propane at 30%. This is why our acceptable range of recovery of +/-2% is important to prevent over/under normalization. In other words, if recovery is outside of the test parameters, the analyst would know to expand their analysis to either a different or different instrument to determine what the missing percentage could be. In this example, if the analyst expanded the test to parse the full hydrocarbon range, there would be an acceptable level of recovery and both nButane and Propane would appear at their accurate proportions.
Applying these procedures to @Killa12345’s example above, if an analyst runs a hydrocarbon analysis with an unlimited acceptable recovery range on a sample containing 80% water and 20% gas (we’ll call it nButane), the analysis will yield raw results of 20% nButane, and the 20% recovery would be normalized to 100%. In proper practice with a reasonably limited recovery range, an analyst would note the unacceptable recovery rate of 20% and change tests to being attempting to identify the remaining 80%.
Additionally, in practice the presence of water specifically would be hard to ignore. The peaks would be very skewed and the baseline would be wavy. The water would interfere with the column polarity and cause huge issues. The analysis would show only the hydrocarbon (nButane) but the recovery percentage would be so low that the analyst would hopefully realize there is a massive problem with the sample. Really even before running the same the analyst should notice the presence of water on the inlet since it behaves so much differently that hydrocarbons ever would.
Now let’s look at this in practical application at the purity levels we’re actually dealing with:
Generally speaking, any analysis is only able to identify the components that it is designed to identify. This is exactly why we separate our different analyses from one another—it prevents the data from being quenched by the presence of high or low percentages. We test hydrocarbon purity first, then sulfurs, then oxygenated/halogenated compounds, all with a reasonable limited recovery threshold. If any of these tests fail our internal standards, we would know we have to further analyze the sample under different methods or with a different machine to determine what we’re dealing with. However, because i) we only test high purity hydrocarbons, we work under a general premise that there are only so many contaminants that would be reasonable to find in a sample, ii) we have fine tuned our analyses such that we are alerted if such contaminants are present to determine if further testing is required, and iii) we will not sell gas into the market that does not pass scrutiny at all three levels, we are very confident in the purity of the product that we are selling (for clarity, I’m only familiar with our internal standards so this shouldn’t be construed to be a blanket statement about the industry as a whole).
You may notice a glaring variable in all of the above examples: Do you trust the analyst? Do you trust their employer? And do you even know what they’re doing or how they’re doing it? This is why I also always say that finding a gas supplier that truly gives a shit about these products and their end usage and who is willing to communicate with you openly and honestly about these types of issues is a vitally important step in addition to holding their products to the standard we develop here.
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