Any latest development in the world of asphaltene inhibitor and asphaltene in general?
Ahmed Helmi
Adjunct Professor at Pharos University
Win: The literature states that the molecular size of Colloidal Particles range from as small as 1 nanometer upto 1 micrometer. The consequent logic tells me that Humberto "should" use a filtration device having pores of 1 nanometer, ie. the smallest diameter for retaining the smallest particle. There is no role for any solvent in this rationale. But the logic tells me one further step: How Humberto would tackle / avoid plugging his filtration device in the very moment of the initial start up of his pilot plant?? Is it the role of high pressure? if so it may work in the beginning of a run but shortly the "high" pressure may cause getting the retained Asphaltenes as a compact layer on the surface of the filtration device. If Humberto could rely on intermittent operation meaning periodically stopping the run to skim the Asphaltene layer off his filtration device, could this be practically acceptable? I doubt. Humberto: Appreciate your elaboration.
Win Robbins
Advanced Characterization - petroleum at Carmagen Engineering
Ahmed,
Asphaltenes have no specific composition, rather the event of precipitation brought on by a change in solvent power (pressure drop, mixed crudes, or solvent addition) crashes a complex mixture of structures out solution. The precipitate includes not only insoluble compounds but a variety of trapped (occluded) solvent molecules. TWhereas the precipitated asphaltenes have a generic discotic (disk-like) character, the molecules within the precipitate slowly re-arrange. Kilpatrick has recently referred to the precipitates as "molecular velcro". In separate papers, Kilpatrick and Gray have published useful hypothetical models showing his type of aggregated material. Analytically, the size of the precipitate is a function of solvent composition and diluent volume; but no analytical technique has been able characterize a monomer of asphaltene. Most analytical methods use solvent/oil ratios >10, preferably >30, and allow the precipitate to age for several hours before filtration on disposable paper filters followed by extensive solvent washing. Such conditions are not economically feasible for a process. The ROSE process mentioned earlier is exception because the CO2 doesn't have to be recycled to be economic.
You are absolutely right about the filtration. Filtration through nano-porous ceramic membranes will remove some of the asphaltenes but at the expense of extreme pressure. After a few hours the pressure drop becomes excessive, recovery of precipitated material by backflush with a good solvent (toluene) is partially successful because the pressure has de-aggregated the asphaltene within the membrane pores leaving some insoluble deposit. After a few cycles, initial pressure drop is too high. In general, filtration is not a practical method for petroleum processing. If phase separation can be achieved predictably, then physical property separations( distillation, centrifugation, liquid/liquid extraction, etc) are more acceptable, especially if the phases can flow. Batch type operations like filtration are only practical for high value products.
Ahmed Helmi
Adjunct Professor at Pharos University
Win:
1- Glad that my previous comment draged you to tell valuable technical information, very educational to me from a subject-matter-expert. Thanks.
2- While reading your comment describing how difficult Asphaltenes detrmination is for the Analytical Chemists I recalled my first day at Prof Dr Mike Delaney's Artificial Intelligence Lab at Boston Univ close to the mid eighties as PhD student: Here we add intelligence to chromatographs and spectrophotometers to predict the structure and concentration of simple molecules as a beginning, Absolute No if you ever think of complex molecules of your Petroleum Industry, No for Asphaltenes or Aromatic Extracts!! At then I realized how carefully he read my CV where I wrote about my humble experimentation for their column chromatographic separation in Egypt, ambitious dreams/curiosity of a junior lab chemist equipped with only a glass column and a refractometer Russian-made.
Humberto:
Still waiting for your elaboration if you don't mind:
Colloidal particles molecular size range from 1 nanometer to 1 micron
Suspended Solids (Can I say "molecular size" here too???) around 10 micron
Which type of Solutes are you targetting for the separation? If there is no solvent added yet; I would expect the Ashaltenes suspended in the oil (dispersion medium) as a stabilized collodal system, meaning in Colloidal Dimensions (1 nano meter to 1 micrometer) not as Suspended Solids as we know the term in water chemistry. Please correct me if I were wrong.
Win Robbins
Advanced Characterization - petroleum at Carmagen Engineering
Ahmed,
Characterization of petroleum has certainly progressed from when you (and I) started with open columns and spectrophotometers. Advances in HPLC, diode arrays, and now high resolution MS (FT/ICR/MS) have allowed us to understand how little we understand about the complexity of petroleum. Petroleum originates from such a broad range of bio-matter, sedimentary conditions, and geo-thermal processes that contribute to this complexity. In the past decade, it has become apparent that many petroleum accumulations are alive with anaerobic and aerobic bio-organisms further complicating crude handling. Ancient bio-marker compounds are being supplemented with extensive genetic coding. Some of the bio-molecules may well be found within the material precipitating as asphaltenes. It's no longer sufficient to consider the origin of asphaltenes in terms of organic geochemistry; we now need to consider organic microbiological geochemistry! Some potential clues linking bioactivity to asphaltenes are now being found on the sea bed around "black smoker" seeps.
Ahmed Helmi
Adjunct Professor at Pharos University
Win: I hope to maintain communication with you. I will write here my website address and 2 publications in which I was coauthor named "Abdelfattah" , a grandfather I don't like as he had a second wife besides my sweet tender grandmom so my family name in Facebook and LinkedIn is "Helmi" my grand grandfather's name. 4- ElGayar, M., Mostafa, A., Abdelfattah, A., and Barakat, A. (2002) Application of geochemical parameters for classification of crude oils from Egypt into source-related types. Fuel Processing Technology, 79, pp. 13-28.
5- ElGayar, M., Abdelfattah, A., and Barakat, A. (2002) Maturity-dependent geochemical markers of crude petroleums from Egypt. Petroleum Science and Technology, Vol. 20, Nos 9&10, pp. 1057-1070.
www.ahelmiconsultant.com Will read your last comment with more concentration after dinner, my Dear Wife gets mad if she announces: Dinner is Ready and I pretend as if not hearing and continue with my Labtop!
Ahmed Helmi
Adjunct Professor at Pharos University
Gents: I appreciate the initiator of this discussion Mike Davis and all the Commentators for extending my vision of Asphaltenes from the macro-scale to the micro-scale. Appreciate Win for a deeper vision beyond the micro-scale, I may call it the Sub-MicroScale. I wrote in a previous comment the need for a joint R&D research program by the Biggies of the O&G Industry to have a universal solution for the Asphaltenes depositional problems. Thanks to the last comment of Win as the Search engine lead me to a valuable published academic report authored by a researcher from the University of Illinois that digs in finding a Universal Solution. Here, I post the Abstract of this report hoping for your comments: G. Ali Mansoori Departments of BioEngineering, Chemical Engineering & Physics, University of Illinois at Chicago, Chicago, IL 60607-7052, USA E-mail: mansoori@uic.edu Abstract: We present a coherent and unified group of general explanations for the various phase transitions, which may occur in the seven naturally occurring petroleum fluids with emphasis on their heavy organics. The seven petroleum fluids include, in the order of their fluidity, natural gas, near-critical gas-condensate, light crude, intermediate crude, heavy oil, tar sand and oil shale. At first the nature of every petroleum fluid is presented including their constituents and their heavy fractions. Then their main families of constituents are presented. The generalised petroleum fluid phase behaviour is introduced in light of the well-known theory of phase transitions. The effects of variations of composition, temperature and pressure on petroleum fluids phase behaviour are introduced. Their 11 distinct phase-transition points are presented and their relation with state variables and constituents are identified. This report is the basis for development of a unified phase behaviour prediction model of all the petroleum fluids. Keywords: asphaltene; diamondoid; heavy oil; heavy organic; hydrocarbon; oil shale; phase transition points; polydisperse fluid; resin; tar sand. Reference: Mansoori, G.A. (2009), ‘A unified perspective on the phase behaviour of petroleum fluids’, Int. J. Oil,Gas and Coal Technology, Vol. 2, No. 2, pp.141–167.
If you read in this report, please see Fig. 8, as I suspect a printing error that spoils my interpretation of this particular valuable data presentation/plot. What do you think?
Win Robbins
Advanced Characterization - petroleum at Carmagen Engineering
Ahmed,
Mansoori makes a valiant effort to come up with a universal model based on phase transitions; however, his references to asphaltene composition and structure is 10-20 years out of date. The only recent reference that he cites for the "continental" model is Mullins (2006). Over the past 20 years the consensus has grown to prefer a mixed model with both continental and "archipelago"( model with a maximum of 6 fused aromatic rings linked by short C-C bonds or naphthenes.) Rodgers (FSU) and Qian (Exxon) have separately used different MS techniques to demonstrate the latter is the dominant structure in most cases. The more open structure is supported by Exxon asphaltene models (Siskin, 2006) and Exxon papers by Freund supporting a patented model for the fragmentation of kerogen and asphaltenes.(US 7,334,889). As for Mansoori's Figure 8, GCP or SEC is not adequate for determining the MW of asphaltenes, it only reveals the apparent molecular size for the asphaltene aggregates at the concentration and in the solvent used for the test.
Ahmed Helmi
Adjunct Professor at Pharos University
Win: I was about to shutdown my Laptop, take a break, then I made a visit to the Group to see if any comment. I am now fully alert and thanks again and again for your generous information about the latest updates in Asphaltenes' research. Mansoori is depending on the PT diagram and its Gas Envelope to characterize the separation of different phase/s per given change in PT and I was about to consider the extension of his approach when it comes to Asphaltenes as exaggeration; but I recalled a scene during a visit to the Lab of a Gas Separation plant west of Alexandria a couple of years ago. An experimentalist chief chemist of that Lab showed me his separated Asphaltenes out of Natural Gas Condensates with Gas Oil at its tail end. He managed to concentrate these Asphaltenes by several consequent distIllations starting with a Large quantity of Condensates. I was shocked as I used to tell my students that Asphaltenes can be found only in Crudes/Residues. Could these separated Asphaltenes precipitated out of the Condensates according to the PT Diagram? Rephrasing; could this support Mansoori's claim? Win: it seems that I always manage to drag you for deeper insights, will this one work?
