Coal experiments, analyses

The results in terms of final sulfur values and pyrite removal are given in Table VIII. Note that pyritic removal computed from either sulfur forms analyses or the diflFerence in total sulfur between processed and untreated coal (Eschka analysis) resulted in essentially identical values of 93-100%. This corresponds to total sulfur removal of 40-70%, depending on the organic sulfur content of the coal. The observation of greater than 100% removal is a result of cumulative error in analysis and the removal of small amounts of sulfate (0.02-0.04%). Presently, these experiments are being duplicated using ferric sulfate, and preliminary analysis indicates the same results. 

The economics of the arc-coal process is sensitive to the electric power consumed to produce a kilogram of acetylene. Early plant economic assessments indicated that the arc power consumption (SER = kwh/kgC2H2) must be below 13.2. The coal feedcoal quench experiments yielded a 9.0 SER with data that indicated a further reduction to below 6.0 with certain process improvements. In the propane quench experiment, ethylene as well as acetylene is produced. The combined process SER was 6.2 with a C2H2/C2H4 production ratio of 3 to 2. Economic analysis was completed uti1i2ing the achieved acetylene yields, and an acetylene price approximately 35% lower than the price of ethylene was projected. 

The analysis of the sample coals used in the experiments are shown in Table 1. 

In another experiment, naphthalene-d8 was used to investigate the chemistry of hydrogen transfer between coal and nondonor solvent at 380°C. An analysis of the recovered naphthalene-d8 showed that approximately 4% of the hydrogen in the coal and in the naph-thalene-d8 exchanged. Most of the protium incorporated in the naphthalene-d8 was found in the a-position. The coal products contained approximately 2 wt % chemically-bound napththalene-d8. 

Experience in this laboratory has shown that even with careful attention to detail, determination of coal mineralogy by classical least-squares analysis of FTIR data may have several limitations. Factor analysis and related techniques have the potential to remove or lessen some of these limitations. Calibration models based on partial least-squares or principal component regression may allow prediction of useful properties or empirical behavior directly from FTIR spectra of low-temperature ashes. Wider application of these techniques to coal mineralogical studies is recommended. 

The technique of H NMR thermal analysis (25) yields data In the form of M2J pyrograms (typical examples are shown In Figures 1 and 2). The fusibility of a coal can be ranked by the minimum value of M2J (M2jmln) attained during the experiment. This parameter measures the Instantaneous maximum extent of fusion of the sample on a molecular level and not the total fraction of material that passes through a fused state during heating. 

The thermal analysis experiments Involved the collection of NMR data while coal samples were being heated at 4 K/mln to 875 K under non-oxldlzlng conditions. 

Statistical analyses were applied to the M2J data from both thermal analysis experiments and measurements on coals swollen with pyridine... 

Support was provided under the National Energy Research, Development and Demonstration Program (NERDDP). T.P. Maher of the Joint Coal Board provided coal specimens and expert advice. P.J. Redllch (Monash University) supplied brown coals and extracted residues. Maceral concentrates were provided by N. Lockhart, C. Davies, M. Shlbaoka, N. Ng and A. Cook. N. Thomas and Z. Lauks performed most of the thermal analysis experiments. 

Table V summarises the data of the sulphur analysis of the hydrocracked liquids and the various bpt fractions for CoMo and NiMo catalysed experiments. The sulphur contents of neither the total hydrocracked liquids nor the individual bpt fractions showed any dependence on repeat contact or catalyst type. The values did show that the sulphur concentrated in the recycle solvent fraction (275-450°C), suggesting that, even under the relatively strong conditions used, certain sulphur-containing compounds will survive to be recycled in the solvent However, the sulphur content of the coal liquid feed was reduced by about 50% and the sulphur content of the likely upgradable product was low.

Later on the decomposition of cellulose at high temperature was examined by a number of authors. Most of the research was devoted to the problem of the origin of coal. The experiments of T. Urbanski at al. [50] using infra-red spectroscopic analysis for the examination of the products of thermal decomposition of cellulose are described in Vol. III. (Charcoal for blackpowder manufacture). 

Solids Sampling and Analysis. The coal consumption data is compiled in Table II. The ash, BTU, and sulfur analyses on the coal consumed during the 1-wk test period is presented in Table III. The data from the mercury in coal determinations are given in Table IV. Based on the authors experience with mercury in coal studies, the resulting concentrations are average for eastern United States coals. The author has found the spread in the individual coal determinations to be common when analyzing 0.5-g samples. The data in Tables III and IV show a relation-... 

Materials. Analyses. The coal analyses are given in Table II both black durain and cannel coals are rich in sporinite material while the remainder are highly vitrainous. Two experiments were also carried out with material other than coal one with Neospectra carbon black and the other with a soot residue formed by the reaction of coal (CRC 802) in the plasma. The analysis (% daf basis) of the Neospectra carbon black was as follows C, 92.0 H, 0.8 N, 0.05 O by difference, 7.2 volatile matter, 9.2. All the materials were vacuum dried at 110°C. for several hours prior to use. 

Nitrogen. The gas analysis given in Table IV shows that the nitrogen in the coal was converted to hydrogen cyanide in the plasma jet. The results of experiments on adding nitrogen to the jet are summarized in Table VI. As the concentration of nitrogen in the jet was increased, the conversion of the... 

Analysis of the coal used in these experiments and of a typical char from the lignite coal produced during a series of runs through the hydrogenator are shown in Table 1. The analyses are on a moisture-free basis and were obtained by the U.S. Bureau of Mines using standard ASTM analytical procedures. 

Figure 2 shows the results of the pyrolysis experiments conducted with the Spanish lignite at 750-960°C at residence times of 0.52-0.72 sec. It is seen that under the pyrolysis conditions used, 60 - 70% of the sulfur in this coal appears in the gaseous products as H2S, COS, and CS2. As in the previous sulfur study (1), the principal sulfur gaseous product at all temperatures is H2S, with some CS2 formed at T >840°C. The CS2 is apparently formed at the expense of the H2S, by any of several reactions H2S may react with the carbon of the coal and/or the methane evolved in the pyrolysis of the coal to form CS2- A small amount of COS is detected at all temperatures trace amounts of SO2 are also detected. Moreover, the total sulfur yield appears to reach a maximum about 900°C. The decrease in sulfur volatilization as pyrolysis temperature is increased above 900°C is attributed to sulfur retention in the char due to the reaction of H2S with coke or char to form more stable thiophenic structures (2). GC/MS analysis of the tars (diluted to 10 ml) from the pyrolysis at 750 and 850°C did not reveal any sulfur-containing structures. Tars from the pyrolysis at 900 and 950°C, however, contain dibenzothiophene. 

Table I contains the elemental analysis of the T102 bottoms, the material brought overhead with toluene, the residue remaining after the toluene destraction, and the starting coal used at Wilsonville during Run 242. The toluene overhead represented 66.8 percent of the material charged to the FDU, and the residue accounted for 27.9 percent. Other material collected from the FDU includes 4.2 percent in the spent solvent and 2.7 percent recovered during cleaning of the FDV and separator with tetrahydrofuran. The total material balance is 101.6 percent. This number also includes any residual toluene or tetrahydrofuran in the various samples. The overhead collected from the five destractions was ground and combined before use in the reflux mode experiments.

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