| Author | Message | ||
     Juan Gutierrez |
Bruce, I work at refinery and so interested on knowing if it is affordable to use NIR or even MIR to infer traces of contaminants in ppm by means of chemometrics. Nowadays the aromatics complex use GC-on line to control the differents streams, but these equipments are a little old and require a lot of time in maintance and calibration, in addition they only use a isothermal runs. I read and article about using NIR on this kind of complex but I did not get any data about resolution or detection limit either. | ||
| Bruce H. Campbell (Campclan) |
Juan, The usual detection limits are of the order of 0.01 to 0.05 percent and those are for organics with hydrogen bonded to carbon, nitrogen, or oxygen. There is one detection limit that I found and that is for nitrogen/hydrogen. When the part of the spectrum with that principla band was not obscurred by other bands, the detection limit was about 0.001 percent. If your contaminant is a sulfur/hydrogen material, the usual dection limits are usually much higher. Bruce | ||
| Juan carlos gutierrez Camperos (Juank) |
Thanks for replying Bruce, the major contaminants are HC compunds in ppm. For instance Benzene is one of the product and its regular contaminants are: Non aromatics-C9,C7(around 1000 ppm), Toluene(up to 200 ppm), methylcyclohexane(up to 80 ppm). Do you agree the NIR resolution an detection limit are good enough to replace GC? Juan | ||
| Bruce H. Campbell (Campclan) |
Juan, The levels you give indicate there may be success but it is not assured. I think the action you could take now is to contact an NIR vendor in your area and propose a survey study they could carry out, at little or no cost to you. This study would entail your furnishing them with about 30 samples or so with known amounts of the minor constituents. They would scan the samples and report to you what they found for detection limits. You can then decide whether or not to continue. By the way, you may not need to know the exact levels of the minor components, just if they are above a certain predetermined level. YOu could also consider engaging the services of a consultant. There are some listed in the equipment section of this system. Bruce | ||
| mpdc |
Also keep in mind the origin of the oil. If all of your oil comes from a limited number of wells, the variation between samples will be less and you have more chances for success. This factor becomes of course less important as your products get more refined, but can play a significant role in the first stages of refining. | ||
| Kathryn Lee |
Juan, There are great advances in GC technology, miniturization, etc. Although this is a NIR forum, you might want to investigate upgrades to the GC technology with which you have some experience and knowledge. Learning how to do NIR will be a big time (and therefore money) investment, and if you hire a consultant, a shorter time but possibly bigger money investment. NIR also requires some continuous attention. Many people at the recent meeting on Process Analytical Technology noted that it is very important to understand processes, and doing a second technique such as NIR and comparing to your GC results may provide a lot of knowledge about your process, making it a very good investment. Understanding processes requires a lot of knowledge, time, and money as well, but may provide large payback. |