Could there be potential reactive hazards in your facility you’re not aware of? Don’t let undesired reactions lead to uncontrolled situations and reactive chemical incidents. In this ioKinetic sponsored webinar, learn an approach to identifying and characterizing reactive materials and how to reduce the risk associated with chemical handling, including runaway incidents and explosions. Examine how to select appropriate test methodologies and use them to identify potential reactive hazards. Discover experimental design concepts and data analysis using instruments such as Differential Scanning Calorimetry, Thermogravimetric Analysis, Accelerating Rate Calorimeter, and Automatic Pressure Tracking Adiabatic Calorimeter. This webinar also provides an overview of tests results and how to use test data to manage hazards of reactive chemicals.
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Q. What is the phi-factor mentioned in the adiabatic testing?
A. The phi-factor is a ratio of the sample mass to the test vessel mass and it represents how much is really left to the test vessel mass. You might have seen in that picture, the arch that I showed you, the arch has the thermal couple on the outside but we have to actually heat up the metal before we measure the temperature so it’s really a quasi-adiabatic system. The phi-factor will be designed for each test because it’s based on the masses that are present. It is then calculated separately for each test.
Q. Is there any literature available that provides results of ARC or similar tests for specific chemical systems or is it all proprietary?
A. There has been a lot of data published on the more commonly used or the larger scale industrial operations. There is data on styrene, there is data on peroxides, there is data on polymers. I would suggest looking at some of the historical data that’s been presented at the DIERS bi-annual meetings. The Design Institute for Emergency Relief Systems (DIERS) is an AIChE organization, and a lot of data is presented at those meetings and shared amongst the member companies. Other than that, I would suggest searching the AIChE quarterly publication Process Safety Progress for data. Doing a literature search is your best bet.
Q. Do you have suggestions for any reference books for hazards of the scale of engineering when we want to scale up a reactor?
A. Yes, there are some really good guidelines coming out of the CCPS Guidelines Series. There is the Essential Practices for Managing Chemical Reactivity Hazard that I mentioned earlier but there are also a couple of other books there that talk about scaling up and how to evaluate the hazards associated with that.
Q. Are there scenarios where you would recommend multiple tests to better characterize a reaction speaking from a cost perspective? Are the multiple tests costs additives? For example, if these cost $4,000 to $5,000, could an employer find themselves needing over $15,000 worth of testing for a single reaction?
A. Well, there are cost-effective ways to approach that. You could start by doing maybe a differential scanning calorimeter testing of the individual component and then only doing ARC testing of those where you find a hazard might be present. Or you could take the approach where you are just going to look at the reaction mixture to make sure you have controls in place so that you do not isolate those other components. A lot of analysis work can be done with one test. Ideally, we prefer to look at all the different components of a reaction mixture, but we’re aware that it could be cost-prohibitive for a lot of companies.
Q. What is PSM regulation?
A. That is OSHA’s regulation, Process Safety Management regulation. It’s found under the 29 Code of Federal Regulations (29 CFR 1910.119). Just a quick search on the OSHA website will pull it up. It’s a 14-element standard that came into play in 1992 and it was intended to reduce the number of process safety-related incidents in the chemical process oil and gas refining industry. It has been done to a certain extent, but obviously, we are still learning.
Q. If a reaction is considered unventable with standard relief equipment, what options are available?
A. There are options like quenching or dumping. So you could have a huge opening on the bottom and dump it down into a larger vessel, which is quenching. Or, you could start to get into some really detailed high-end control systems. You can sometimes control things using temperature and make sure that you do not end up in that situation. But then you start to get into things like the safety integrity level of control systems and such, so you must make sure you can rely on those.
Q. How easy is it to develop binary interaction matrixes for reactive mixtures involved in two or more reactions? How can I make sure these matrixes are sufficient, especially when these reactions could also involve reactions with intermediates or even reaction products?
A. The initial approach of putting together an interaction matrix is very simple. You essentially choose your materials and then tell the software to go ahead. It starts to get challenging when you find out that you have materials that may not be in a standard database. I actually have a presentation on that which I can forward to you if you like. Just send me an e-mail with this question. We generally rely on special analysis and a chemist to help us identify what the functional roots might be of some lesser-known materials. That way we can shrink down the matrix and get the information needed.
Q. Can you explain more about the software that simplifies the evaluation of chemical reactivity hazards?
A. One software I mentioned was CAMEO, which provides interaction matrices, but there are other software that allow us to do data analysis and then develop Arrhenius expressions. ioMosaic’s proprietary software SuperChems™ allows for sophisticated data analysis in terms of doing an initial estimate of the Arrhenius parameters, and it also does a higher level fitting of those parameters to make sure that we have taken into account the vapor-liquid equilibrium and such. Both CAMEO and SuperChems™ have a fairly large database of materials. SuperChems™ has 4,500 chemicals in its database but if you don’t have either of those databases you get into predicting them using the Benson or Jobak systems and such.
Q. Where can a list of binary interaction parameters be found? What do these parameters really tell me?
A. There is no real list. What you do is you generate the matrix, by entering in the potential materials that could come into contact with one another, then generate the matrix, and that will generate the list of the chemical interactions that could happen, the potential interactions. What it’s going to tell you is, if I had a material that came into contact with something else, whether or not I should be concerned, whether I need to keep these apart, etc. It’s a conservative approach. These matrices are by definition highly conservative in nature so you need to make sure that you apply those concepts to the reality of the operation that you have. So let’s say I was worried about two components, component one and component two, coming into contact with one another. Maybe they are on opposite sides of the plant, maybe one is in a small quantity. So you will want to interpret these matrices keeping in mind the actual operation that you have.