Carbon Reactions

 

FSC 506

Spring 2009

TR 8:00-9:15 A.M.

116 Earth & Engineering Sciences Building

 

 

Instructor:      L. R. Radovic,  Professor of Energy and Mineral Engineering

                        205 Hosler Building (phone: 863-0594; e-mail: LRR3@psu.edu)

 

Contents:        The basic tools of physical chemistry, chemical thermodynamics, kinetics, transport phenomena and materials science are used to discuss the formation, properties and reactivity of the ever important and increasingly diverse group of carbon materials, which range all the way from coals to the undesirable soot, from carbon blacks and activated carbons to graphite, as well as the highly coveted diamonds and the recently discovered fullerenes and nanotubes.

 

Approach:      In addition to providing a brief overview of the topics summarized below, this course is PRIMARILY meant to be an exercise in the methodology of reading (and writing) scientific publications.  Each topic will be covered by analyzing a specific paper (recent or classic).  The background for each paper will be provided in class and it will be reinforced by reading selected cited references.  The impact of each paper will be assessed by analyzing selected citing references. (Note: When the class enrollment allows it, the selection of topics to be discussed is adjusted to accommodate the specific interests of the students.)  

 

Homage:         This course is a direct ‘descendant’ of the legendary lectures (with the same title and same number) by Prof. Philip L. Walker, who died on March 22, 2009. It is offered in fond memory of the priceless lessons that Prof. Walker instilled in this instructor and in many other ‘disciples’ worldwide: the passion and the joy of learning and the intellectual honesty in the pursuit of excellence. Prof. Walker’s entire research opus is available here. A Festschrift issue of the Carbon journal honoring Prof. Walker was published in 1991 (Vol. 29, No. 6, www.elsevier.com/locate/carbon).

 

 

A.    Fundamentals

 

1.    Formation of Carbons

       (a) Gas-phase reactions (pyrolysis, CVD)

       (b) Liquid-phase reactions (carbonization)

       (c) Solid-phase reactions (thermal decomposition)

 

2.    Structure and Characterization of Carbons

       (a) Bulk properties (chemical bonding, crystallinity, morphology)

       (b) Surface properties

            -physics

            -chemistry

 

3.    Reactions of Carbons

       (a) Solid/gas reactions

       (b) Solid/liquid reactions

 

 

B.    Applications

 

       1. Gas-phase carbon products: carbon black (soot), pyrolytic carbon, diamond, fullerenes, nanotubes

       2. Liquid-phase carbon products: coke, graphite, carbon fibers and composites

       3. Solid-phase carbon products: molecular sieves, activated carbons, catalyst supports

       4. Miscellaneous: carbon electrodes, regeneration of coked catalysts, catalysts.

 

 

Introduction to the literature: Chemistry and Physics of Carbon series of monographs (vols. 1-30), Marcel Dekker, 1965-2008.

 

 

Template for Semester Paper

            -Proposed TITLE due as early as possible (in Angel dropbox), final version by February 28.

            -Proposed OUTLINE (Table of Contents) – preferably including the preliminary List of References as well as the selected paper for detailed analysis -- due before March 15.

                        -Discussion of general issues:

                                    -by subtopic (=> judicious selection of subsections...)

                                    -sequencing of papers to be discussed

                                                -by concept (preferable!?)

                                                -in chronological order (smooth transitions?!)

            -1st (rough) draft of PAPER due as early as possible, preferably by April 12.

            -Individual discussions (15 min-1 h) of the current draft during the week of 4/20.

            -Final version of PAPER due by May 3.

 

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Examples of previous class discussions of papers:

 

Week of 1/29:
Title: THE SURFACE-STRUCTURE AND REACTIVITY OF BLACK CARBON
Author(s): SMITH DM, CHUGHTAI AR
Source: COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS 105 (1): 47-77 DEC 1 1995

Here is one version of the annotated MS… for Thursday discussion.

Some specific discussion issues:

-Did Smith and Chughtai really perform “BET adsorption measurements”, as claimed by Smekens et al. (2005)?

-Müller et al. (2005) say that “oxygen containing [sic] functional groups attached to non-six-membered rings may occur as very reactive sites [17]”, where Ref. 17 is the Smith and Chughtai paper. Comments about this citation?

-Zawadzki et al. (2003) also studied the carbon-NO2 reaction using IR spectroscopy. Did they make, and should they have made, any SUBSTANTIVE comments about the results or findings of Smith and Chughtai?
-Chughtai et al. (2002) say the following: “The band at 1725 cm-1 … is due to carboxylic species whose absorbance reflects the state of oxidation (Smith and Chughtai, 1995).” Based on this statement, what exactly should we expect to find in Smith and Chughtai (1995)? (In which figure/table is the relevant evidence provided?)

-Mawhinney and Yates (2001) say that the “O3-induced formation of [carboxyl] groups has been discussed in [the] literature where the creation of anhydride groups is followed by reaction with water to form two COOH groups.” One of the cited references is Smith and Chughtai (1995). How are the two proposed mechanisms related, if at all? (So, in what context, and for what purpose, is the ‘mechanism’ proposed by Smith and Chughtai (1995) cited here?)

-Kirchner et al. (2000) also studied the kinetics of the soot-NO2 reaction using FTIR. Did they compare their findings with those of Smith and Chughtai (1995)? If yes, was the comparison ‘favorable’? If not, why not?

-Since very little (if any) direct or even circumstantial evidence is presented in this paper (do you agree?), please check at least one or two of the cited reference and see whether you can find there such evidence for some of the more important arguments? For example, what is the message of Figure 5 (which occupies almost an entire page)? How much text do the authors devote to its discussion? Does this figure really show what the authors say it (presumably) shows? Hopefully the original reference says something more profound…

 

One “bottom line” conclusion from our analysis of the Smith and Chughtai (1995) paper is that their ‘cartoons’ (Figs. 10 and 11) are intuitive (as most ‘cartoons’ indeed are). How insightful are they? The jury is still out, and only time will tell (partly based on the authority and ‘credibility’ of the authors)… For VERY insightful cartoons that have withstood the test of time admirably, see R E Franklin, Proc Roy Soc London 1951, A209 (1097), 196-218 (available online through JSTOR). 

 

Week of 3/5:

Solum, M. S., Sarofim, A. F., Pugmire, R. J., Fletcher, T. H., Zhang, H., 13C NMR analysis of soot produced from model compounds and a coal, Energy & Fuels, 2001, 15, 961.

            -Here are some considerations for our Thursday discussion.

            -Here is a detailed quantitative analysis by Daniel and Meredith.

 

Week of 3/19:

Müller et al., “Diesel Engine Exhaust Emission: Oxidative Behavior and Microstructure of Black Smoke Soot Particulate,” Env Sci Technol 2006, 40, 1231-6.

            -Here is some (deliberately provocative) food for thought, and for our Thursday discussion... (Need to take back (m)any of these comments?) 

 

Week of 2/19:

Himeno, S., T. Komatsu, and S. Fujita, High-pressure adsorption equilibria of methane and carbon dioxide on several activated carbons. Journal of Chemical and Engineering Data, 2005. 50(2): p. 369-376.

            -Some comments and suggestions to stimulate our Thursday discussion…

            -Here is an example of the important exercise to (attempt to) reproduce some of the authors' results…

 

Week of 1/17: Clague et al., “A comparison of diesel engine soot with carbon black,” Carbon 37 (1999), 1553-1565.

            -Examples of discussion issues:

                        -A bit more information on the relevance would have been useful… For example, is “soot thickening” the MAIN reason for starting problems (as implied by issue #1 in Table 1)?

                        -Dispersion (e.g., prior to particle size analysis) is a key issue (Figs. 4,6,7)… Is the dispersing agent used similar to the lubricating oil? If not, are the results obtained relevant (i.e., generally applicable), as implied by the last sentence in the Abstract?

                        -What exactly are we supposed to see in Fig. 1? Do the authors see more or less than, for example, Vander Wal and Tomasek in their paper?

                        -Do the authors compare (i.e., discuss the consistency of) the particle size distribution seen in Figure 2 with that obtained in Figs. 4-7?

                        -Why is Figure 5 interjected between Fig. 4 and Figs. 6 and 7? Is 3D representation useful? Is it necessary? Does it contain a (clear and/or convincing) message?

                        -Are the soots shown in Fig. 3 more similar between them than each one of them with respect to the carbon black? Is that what we are supposed to see? Or is the ‘story’ of this figure more informative and subtle than that?

                        -Inclusion of additional samples, beyond what is described in Table 1 (and in the Experimental section?), can be a very effective tool to provide additional insight and confirm or validate a hypothesis generated from the analysis of the original data set. Is that the cased here (see, for example, Figure 5)?

                        -Speaking of sample selection… If the objective is to see whether CB can be a good surrogate for soot (both in terms of surface chemistry and surface physics), why didn’t the authors select the CBs accordingly? For example, channel blacks are known to have a much higher oxygen content than furnace blacks, and much closer to that of soot B. (Why does the elemental analysis of soots A and B not include their oxygen content?) And CB manufacturers often report particle size distribution data… Why are these not listed (and judiciously selected) in Table 1?

                        -Some of the figure captions are quite vague… Which ones from Figs. 8-14 are unacceptably ambiguous? And are these figures just “filling material” or do they support a ‘story’? (And is that the story on which the main conclusions of this paper are based?)

                        -In Figure 10, what are we supposed to see in the lower graph that we cannot see in the upper graph?

                        -Is Table 3 OK? What is its message?

                        -The Discussion has some 40 lines of text… The Conclusions section has more than 50… And the Results section? Any problems with this distribution? (Developing a feel for what belongs where, and to what extent, is a VERY important component of effective writing…)

                        -Does it make sense to separate the Conclusions section into subsections? Can it be justified in this case?

                        -Let’s (try to) identify those statements in the Conclusions section that ARE supported, more or less directly, by the tables and figures presented. Let’s also (try to) identify those statements in the Conclusions sections that ARE NOT.

 

A viewpoint article worth looking up: “How scientists cheat science and the public”, by Rustum Roy, Centre Daily Times, 11/01/1992, p. 5B:

            “How do scientists cheat science and the public? By not doing their sacred duty and reading, using and giving credit to what has already been done and recorded. Isaac Newton said of this tradition in science of learning from and using what has gone before, ‘We stand on the shoulders of giants.” That’s what we scientists preach. Now let’s look at our practice… What are the results of this non-reading and also non-citing of the literature? First, of course, it is a degradation of the honesty and integrity of the science system. Second, it is simply cheating the public or who[m]ever else is paying for the research. Why? Because a scientist may very well be repeating work already done. Third, it makes for much worse science because it means that one is missing key ideas or data which would improve one’s work…”

 

In-lieu-of-class activities during the week of x/yz:

1.      Submit a paper for initial individual discussion, in pdf format, as an e-mail attachment, by Monday morning (at the latest).

2.      Submit a list of papers-candidates for class discussion. Criteria: (a) papers relevant to class subject matter (see TofC above); (b) papers important for your research; (c) papers you ‘like’ (preferably, and at least for now) or ‘dislike’ (if dealing with really important issues); (d) papers you need help with, to understand more thoroughly.

3.      Annotate paper from (1). Include as many questions/comments/answers/opinions as you can, paying special attention to at least the following:

a.       Does the Introduction “set the stage” properly for what follows, in terms of (i) background info, (ii) definition of the issue, and (iii) approach (hypothesis) adopted to clarify the issue?

b.      Which figures/tables contain the main message(s) of the paper? Are the remaining figures/tables just “filling material” or do they contain ancillary messages and thus support the main message(s)?

c.       Identify those statements in the Conclusion(s) section that ARE supported, more or less directly, by the tables and figures presented; identify those statements in the Conclusion(s) sections that ARE NOT. If there is no such section, why not? And if not, is it a ‘fatal’ flaw?

Submit as e-mail attachment by midnight Tuesday.

4.      Receive (hopefully by midnight Tuesday) my own comments on paper from (1) and compare them with yours. (If my comments arrive late, you can of course take the weekend to prepare and send your final version of the annotated paper; see #5 below.)

5.      Submit (by midnight Friday, at the latest) a final version of annotated paper (as e-mail attachment), including analysis of at least two cited and at least two citing references. Do the cited references REALLY support the statements made by the author(s)? Do the citing references say anything substantive about ‘your’ paper, and do they ‘fairly’ adopt any of the take-home messages of ‘your’ paper?

Note: The annotated papers are available on Angel. Please take a(t least a brief) look at each one of them!

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A study of citing papers, both formal and substantive, is a very important (and too often neglected) exercise. Let’s update this graph for the classical paper by Rosalind Franklin (Proc Roy Soc A209, 1951, 196-218). Comments?

 

It’s good practice to redraw important graphs from papers that are important for one’s own research. Here’s one from Franklin’s paper. Do ALL the data points correspond to the numbers shown in the relevant table? (Are both the table and the figure necessary?)

 

In-lieu-of-class activities during the week of 01/19:

1.      Read Franklin’s paper as carefully as possible. Ignore the sections that are difficult to understand and be sure to proceed to the end of the paper, and then focus more only on the parts that are related DIRECTLY to the conclusions of the paper.

2.      Annotate assigned paper. Include as many questions/comments/answers/opinions as you can, paying special attention to at least the following:

a.       Does the Introduction “set the stage” properly for what follows, in terms of (i) background info, (ii) definition of the issue, and (iii) approach (hypothesis) adopted to clarify the issue?

b.      Which figures/tables contain the main message(s) of the paper? Are the remaining figures/tables just “filling material” or do they contain ancillary messages and thus support the main message(s)?

c.       Identify those statements in the Conclusion(s) section that ARE supported, more or less directly, by the tables and figures presented; identify those statements in the Conclusion(s) sections that ARE NOT. If there is no such section, why not? And if not, is it a ‘fatal’ flaw?

Submit to appropriate Angel dropbox by midnight Tuesday.

3.      On Wednesday analyze my own comments on paper from (1), as well as those of your classmates, and compare them with yours.

4.      Submit (to the appropriate Angel dropbox, by midnight Friday at the latest) your final version of annotated paper, including analysis of at least two cited and at least two citing references. Do the cited references REALLY support the statements made by the author(s)? Do the citing references say anything substantive about ‘our’ paper, and do they ‘fairly’ adopt any of the take-home messages of ‘our’ paper?

5.      Communicate with me by e-mail regarding your initial thoughts and proposal for the preliminary title of your semester paper.

 

 

 

List of papers to be discussed during Spring 2009:

 

-Week of 01/25: “Interpretation of Char Reactivity Profiles Obtained Using a Thermogravimetric Analyzer”, Energy & Fuels 2008, 22(1), 317-320.

 

-Week of 02/01: “Origin of superhigh surface area and microcrystalline graphitic structures of activated carbons”, Carbon 30 (7), 1075-88 (1992).

 

Note: There will be no class meetings on 01/29 and 02/03. Instead, please do the following:

(i) Upload your preliminary annotations on the Naredi&Pisupati paper, including as many specific questions as necessary, by midnight 01/29.

(ii) Study the annotations of your classmates. Try to identify (and then read) the key cited (and any citing?) papers. Analyze the specific issues/questions/comments that will be posted on the class web site. Upload your final annotations on the Naredi&Pisupati paper, including as many comments regarding the issues raised as possible, by midnight 02/01.          

 

(iii) Read the Kaneko et al. paper and be prepared for its detailed discussion in class on 02/05.

            -Do you agree that the meain message of this paper is the following? Some activated carbons DO have a TRUE surface area in excess of 2000 m2/g, which is NOT due to the use of the BET equation and capillary condensation (volumetric pore filling) of N2 at low relative pressures as a consequence of proximity of pore walls.

            -In what context do the citing papers (>10 per year) discuss (or only mention?) this paper? For its main message? For the curious effect of water? Does anyone question the validity of Figure 4, in which the ratio of ‘external’ to internal (‘porous’) surface area is arguably VERY unrealistic?

 

-Week of 02/08: “A study on the char burnout characteristics of coal and biomass blends”, Fuel 86, 2431-8 (2007).

            -Select at least one cited reference and verify whether it REALLY contains the information (or arguments) that the author says it contains.

            -Does the author explain WHY the presence of biomass “increases the likelihood of char extinction” when intuitively (because biomass has more volatile matter than coal and biomass char is typically more reactive than coal char) one would expect (?!) exactly the opposite? (Is the argument from “modelling results” convincing: “a reduction in the char particle size to a level below a critical dimension”? Shouldn’t a smaller particle size be favorable for an increasing burnout level, rather than a decreasing one? What is the physical significance of a ‘critical’ particle size?)

            -Does the author REALLY know his “Rossin-Rammler type size distributions”? Isn’t this such an important concept for him that one would expect a greater display of ‘authority’ here? Can you find the primary source of information on this issue?

            -Is the size of the cloud radius ‘realistic’ (e.g., Table 2)? Any discussion of this (important?) point (especially in relation to the particle sizes)?

            -What is the significance of Figure 7 in relation to coal/biomass blending? Can you construct a similar graph for coal/biomass blends from the results presented in this paper? Is it important to do so?

            -Which figure(s) in the paper “clearly demonstrate(s) that the extinction characteristics of char clouds are distinctively different from those exhibited by isolated char particles”?

             -Is any evidence presented in this paper that biomass is indeed a “less reactive fuel” than coal? Isn’t the opposite typically reported in the literature, and isn’t the opposite what one would expect intuitively?

                                        

-Week of 02/15: “Exhaust Emission Through Diesel Combustion of Mixed Fuel Oil Composed of Fuel with High Volatility and That with Low Volatility”, SAE-2004-01-1845.

            -The authors spell out clearly their conclusions from this study. Which ones are supported directly with their own results? Which ones are supported by indirect (‘circumstantial’) evidence from this or other similar studies? Which ones, if any, are NOT supported in such a manner and are thus the product of (wild? unwarranted?) speculation?

            -Even though we cannot benefit from a quick SCI analysis of this paper, it should be relatively easy to determine whether a graph such as that shown in Figure 6 has been reported (and explained?) before… Let’s compare notes on this “Sherlock Holmes investigation”.

            -If Figure 6 is not the claim to fame of this paper, which one is? (According to the authors? In your opinion?)

 

-Week of 02/22: “C-13 solid-state NMR of Argonne premium coals”, Energy & Fuels (1989) 3, 187-193.

            -Let’s skim through the (>200!) citing papers in search of the following information: Does anyone question or support the finding that lignite clusters contain (on average?) 8 fused benzene rings, whereas lvb coal clusters contain some 18 fused benzene rings (Figure 7)? Does anyone say something about Figure 8 and its (convincing?) interpretation offered by the authors?

            -Among the interesting citing papers, there is one (or more?) showing the use of the same tool to help elucidate the chemical structure of soot. Can you find it? Is NMR more or less powerful in this case? Does this citing paper help us to (better) understand the cited paper? (Usually it’s the other way around…)

            -Has NMR been (equally?) successful in helping to elucidate the chemical structure of other cabron materials? (What would be the Web of Science keywords for an effective search in this direction?)

            -Is there a pressing need to understand some of the key features of the NMR technique (e.g., dipolar dephasing) in order to understand (and accept?) the main message(s) of this paper?

 

-Week of 03/01: “Synergistic effect of mixing dimethyl ether with methane, ethane, propane, and ethylene fuels on polycyclic aromatic hydrocarbon and soot formation”, Combust Flame 154 (2008), 368.

 

Week of 03/15: “Effect of Coal Characteristics and Molybdenum Sulfide Catalyst on Conversions and Yields of Heavy Products from Liquefaction in Phenanthrene”, Energy & Fuels 1996, 10, 718-725.

            Now that you are hopefully FULLY IMMERSED in writing your literature review part of the semester paper, it is VERY important to exercise the most important skill in writing a good literature review:

            (i) how to summarize the essence (the “main message(s)”) of a paper, and

            (ii) how to make sure that the references really say what you (or any other citing author) say they say!

Let’s practice this skill using this paper.

 

Week of 03/22: “Surface area, pore size distribution and microstructure of combustion engine deposits”, Carbon 1999, 37, 1999-2009.

            -Studying the Introduction section of a paper is a very useful exercise toward learning how to write (or how not to write!?) a good literature review (which is what part I of your semester paper is all about). So let’s pay special attention to it in this paper: Does it accomplish what it’s supposed to accomplish? What is the issue? What is known about this issue? How are the authors going to address this issue (and try to resolve it)?

 

Week of 03/29: “Iron compounds and iron catalysts: Activity in reactions relevant to direct coal liquefaction”, Fuel Process Technol 1991, 29, 199-208.

            -How is direct liquefaction related to carbon reactions? How does one (quickly) ‘get’ the big picture?

            -Is catalysis of coal liquefaction (very?) different from that of, say, coal gasification or from catalyzed soot combustion? What are the key issues in heterogeneous catalysis in general? Does this paper address them? How? Or does it get ‘lost’ in (too?) many ((ir)relevant?) details?

            -Is 4-(1-naphthylmethyl)bibenzyl a ‘good’ model compound for coal liquefaction studies? Has it been used before, or since, by other investigators? Which others have been used?

 

 

Week of 04/05: “Role of Surface Functional Groups in the Adsorption Kinetics of Water Vapor on Microporous Activated Carbons”, J Phys Chem C 2007, 111, 8349-8359.

            -how does (can?) one distinguish between effect on kinetics vs. effects on thermodynamics?

 

 

Week of 04/12: “The combustion of coal and some other fuels”, Proc Combustion Institute 2000, 28, 2141-62.

            -or how (not?) to write a (‘good’?) literature review…

            -there is nothing more difficult, and more powerful, than “seeing the forest for the trees”…

            -the most challenging (and exciting?) part of research is not (paradoxically?) actually doing it… it’s figuring out what to do and why, and not so much how…

 

 

Weeks of 04/19 and 04/26: individual discussions of draft of semester paper.

 

 

LRR3@psu.edu (updated 04/13/2009, 9:30 pm)