Carbon Reactions

 

FSc 506

Spring 2007

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

203 Leonhard Building

 

 

Instructor:      L. R. Radovic,  Professor of Energy and Geo-Environmental 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 increasingly important and diverse group of carbon materials, which vary all the way from coal to the undesirable soot, to graphite, and also to 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.)  

 

 

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.

 

 

Template for Semester Paper

            -Proposed TITLE due before the end of February

            -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 13.

            -Individual discussions (15 min-1 h) of the first draft during the week of 4/23.

            -Final version of PAPER due by May 6.

 

 

List of papers to read this semester… by “popular demand” (please verify that the references are correct and complete):

 

 

Discussion on 4/17:

Gül, Ö. Rudnick, L.R. and Schobert, H.H. Delayed coking of decant oil and coal in a laboratory scale coking unit. Energy Fuels 2006, 20, 1647-1655.

 

 

Week of 2/5:

Westbrook, K. C., Pitz, J. W., and Curran, J. H. Chemical kinetic modeling study of the effects of oxygenated hydrocarbons on soot emission from diesel engines. J. Phys. Chem. A 2006, 110, 6912-6922.

      The desired outcome of the first ‘reading’ of a paper (Title à Abstract à Figures/Tables à Conclusions) is the formulation of questions for further analysis, as well as of a hierarchy of such questions. So here is an attempt to accomplish this. Some of these questions will be answered upon more detailed reading, others will not (either because of the limitations of the reader, or of the paper itself). That’s the most effective way to generate interesting AND legitimate questions for FURTHER RESEARCH… (The frightening alternative, not as uncommon as it should be, is NOT to read enough, and then too many (non?)issues appear to be “unresolved” and worth studying further.)

(a) Questions to be answered in order to ‘buy’ the MAIN message(s) of the paper:

      -??

(b) Questions to be answered in order to accept any of the ancillary messages of the paper:

      -??

(c) Other questions:

 -??

 

 

Week of 2/26:

Xu, X., Y. Matsumura, J. Stenberg, and M.J. Antal Jr., Carbon-catalyzed gasification of organic feedstocks in supercritical water. Industrial & Engineering Chemistry Research, 1996. 35: pp. 2522-2530.

      -Here are some comments for our Thursday discussion.

      -Some background information on heterogeneous reactions and the role of, and possible complications due to, mass transfer in them:       Notes1             Notes2

      -Here is a simple thermochemical analysis… Can you extend it to a more ‘realistic’ case? And will the conclusion be the same, and consistent with the authors’ statement?

      -Does any one of the 74 citing papers say anything substantive about some of the critical issues in this paper (e.g., role of mass transport, need for supercritical water, distribution of products “far from equilibrium”)?

      -This paper is a good opportunity to scrutinize in detail an argument in which the authors seem not to be able to distinguish clearly between a hypothesis and a conclusion. The two should not be confused.  An initial set of results leads to a hypothesis. The hypothesis is then tested using new, independent results. This then allows the formulation of a conclusion. What is/are the experimental fact(s) here? What is the proposed explanation for the observed trend? Are other relevant trends consistent with this explanation? What is the appropriate conclusion that can be drawn?

 

This last point goes to the heart of the scientific method… Is the relationship hypothesis ßà conclusion (essentially) the same as the relationship theory ßà law (of nature)?

 

 

Discussion on 5/3:

Osada, M., O. Sato, M. Watanabe, K. Arai and M. Shirai (2006). "Water density effect on lignin gasification over supported noble metal catalysts in supercritical water." Energy & Fuels 20(3). pp. 930-935.

 

 

Discussion on 4/12:

"Kinetics and visualization of soot oxidation using transmission electron microscopy,"  H. Jung, D.B. Kittelson, and M.R. Zachariah. Combustion and Flame, Vol. 136, pp445-456, 2004.

 

 

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.

 

 

Discussion on 4/10:

Lu, L.; Sahajwalla, V.; Kong, C.; Harris, D., Quantitative X-ray diffraction analysis and its application to various coals. Carbon 2001, 39 (12), 1821-1833.

 

 

Discussion on 5/1:

Schneider et al., “Mass spectrometric analysis and aerodynamic properties of various types of combustion-related aerosol particles,” Int J Mass Spectr 2006, 258, 37-49.

 

 

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 3/26:

Sano et al., “Two-step adsorption process for deep desulfurization of diesel oil,” Fuel 2005, 84, 903-10.

            -Can you relate the amounts of adsorbed S-containing compounds to any property of the adsorbent (e.g., its surface area)? Did the authors try to do that? (Should they have, if not?)

 

Discussion on 4/26:

Ania and Bandosz, “Importance of Structural and Chemical Heterogeneity of Activated Carbon Surfaces for Adsorption of Dibenzothiophene,” Langmuir 2005, 21, 7752-9. 

 

 

Week of 4/2:

“Soot Formation in Hydrocarbon/Air Laminar Jet Diffusion Flames,” Combust Flame, 1996, 105, 132-146.

            -Here are some comments and discussion issues.

 

 

Week of 2/12:

Kunzru et al., “Thermal Cracking of n-Nonane,” Ind Eng Chem Proc Des Dev 1972, 11, 605-12.

            -Is it true that the ‘typical’ paper from the “old days” is “much better” than a ‘typical’ recent paper? (Is there a simple definition of a “good paper”? That is, beyond saying “I know one when I see it”…)

            -Here is a preliminary analysis of the authors’ results. Please double-check ALL the calculations and we’ll discuss them briefly next week…

 

 

Discussion on 4/24:

K.J. Hüttinger, “CVD in Hot Wall Reactors: The Interaction Between Homogeneous Gas-Phase and Heterogeneous Surface Reactions,” Chem Vap Depos 1998, 4, 151-8.

 

 

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…

 

 

Discussion on 4/19:

Gomes, V.G. and K.W.K. Yee, Pressure swing adsorption for carbon dioxide sequestration from exhaust gases. Separation and Purification Technology, 2002. 28(2): p. 161-171.

 

 

Paper #1 (1/17/07, gas-phase formation of carbons): 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 1/21:

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!

 

 

LRR3@psu.edu (updated 04/18/2007, 3 pm)