chemical physics of discharges - Argonne National Laboratory
chemical physics of discharges - Argonne National Laboratory chemical physics of discharges - Argonne National Laboratory
436 yield is quite similar. The conversion of carbon to C2H2 for the high volatile bituminous coal (VM 5 39.2%) in table 2 is 9.2% in the H2-Ar discharge as compared to 12.5'1. in the Ar plasma for a coal of similar volatile matter content. TABLE 2. - Reactions of coal and related materials in microwave discharges of H? and Ar 1 Pressure, Percent of c present as ,/ Uaterial m H,, Ar Time, Yield x lo4, mole/g of solid sec H? clll C2H2 CO CO? Gasebus Gaseous products hydrocarbons hvab 22.7 2.3 60 63.9 4.7 31.1 21.1 22.7 2.3 60 53.6 10.2 28.6 20.2 23.4 2.4 60 12.5 4.5 27.0 23.6 22.8 2.4 90 11 3,9 29.8 22.2 21.8 2.3 105 L/ 4.8 21.0 ' 16.9 21.9 2.3 110 11 3.6 20.0 16.0 - 25.7 17 3.3 .1 1.2 7.1 - 24.0 60 56.4 .9 13.4 23.0 - 23.6 180 44.0 1.1 16.5 22.6 lvb 23.8 2.5 34 1/ 4.1 15.5 7.3 21.6 2.2 60 1/ 3.8 17.5 8.1 - 23.5 60 15.3 .3 3.6 7.7 Lignite 21.6 2.2 60 25.4 2.1 9.3 66.2 22.6 2.3 180 22.9 2.1 7.7 80.3 20.7 2.1 180 26.0 2.1 7.3 69.2 - 24.7 32 50.4 .7 6.9 61.7 - 23.0 60 18.4 .6 5.0 68.4 Anthracite 21.6 2.2 60 11 4.2 8.3 4.0 22.6 2.4 60 11 4.6 9.6 3.0 - 24.0 60 .3 trace trace 2.0 Chrysene 22.7 2.4 10 11 6.5 12.8 2.0 20.0 2.0 30 11 10.4 5.8 trace - 22.0 30 lz.6 .8 2.6 trace Graphite 22.4 2.3 60 11 3.5 2.5 trace 22.6 2.4 60 11 3.4 1.8 trace 11 Net decrease of hydrogen was indicated. 0.2 .2 .4 .2 .2 .2 .1 .2 .2 .1 .1 trace 3.5 1.8 1.7 3.2 3.2 trace trace .1 trace trace trace trace trace 13.6 13.1 12.8 13.1 9.9 9.4 1.5 7.7 8.7 6.1 6.7 2.1 16.7 18.3 ' 16.1 14.1 15.1 3.6 3.9 .3 4.6 3.4 .9 1.2 1.0 I 10.4 10.3 \ 9.4 9.9 4 7.4 7.0 -4 \ 4.3 5.3 ' 5.1 \ 5.6 1.1 4.1 3.3 ::: / 3.1 3.4 ~ 4.4 3.4 \ .9 I 1.2 1.0 \ Solid Product I The solid product obtained from coal is brownish and is similar to that usually observed from the thermal treatment of coal. Uo appreciable amount of solid product was formed from anthracite or from lignite. Though the extent of the gasification for the chrysene was not appreciable, the original white powder was instantaneously converted to a broun solid upon the initiation of both discharges. The infrared < spectra of the solid product and the residual char obtained from the high volatile bituminous coal in the H2-Ar discharge showed the usual aliphatic C-R bands and some weak aromatic bands which are typical of pitch and coal. 3 * 7 1 Effect of Cooling by Liquid Nitrogen Since the indications are that the wnter formed can retard the hydrocarbon formation and that the hydrocarbons produced may undergo further destructive reactions, it can be expected that a rapid quenching of the primary products should give a pronounced effect on the result. Experiments were carried out in a reactor consisting of the i t
437 tube divided by a fritted Vycor disc. The coal was placed on the disc, and was subjected to reaction in the H2 discharge while the lower end of the tube was cooled in liquid N2. Though the process of condensing water and some hydrocarbons at this temperature is diffusion controlled, the effect is pronounced, a's shown in table 3. For both the bituminous coal and the lignite, the yield of the hydrocarbons, CqH2 in particular, was greatly increased. The amount of Hg remaining and the amount of CO produced after the reaction were also decreased. Therefore, the increase of hydrocarbon yield can be attributed mainly to subsequent hydrocarbon formation by reaction of H2 and co; this hydrocarbon yield is greatly enhanced b$ rapid removal of H20 formed. Water-Argon Discharge There is a marked difference between the products obtained from graphite and coal in a water discharge. In the discharge in H20-Ar mixtures, as shown in table 4, graphite yields hydrogen and CO but practically no hydrocarbons; while the coals yield an appreciable amount of CZHZ and some CH4 in addition to H2 and CO. The amounts of Hq and carbon oxides produced in the reaction with graphite rere stoichiometric. The extent of gasification was also rpuch greater for the coals than for the graphite. The active hydrogen species produced in the water discharge did not react further with the graphite or the CO formed from it to produce significant amounts of hydro- carbons. This is further evidence demonstrating that the presence of water vapor retards hydrocarbon formation. For the reaction of a given coal in aR2aAr discharge, an initial H20 pressure of less than 12 mm Hg appears to give the optimum gasification end hydrocarbon production. Higher initial H20 pressures cause a decrease in both gasification and hydrocarbon production. So long as the H20 pressure is not at its highest values, more hydrocarbons are formed than in the Ar discharge. (Also, with the higher initial Hfl pressures, the discharge could not be initiated readily and would not sustain itself for as long as 60 seconds, perhaps due to too large an increase in the total gas pressure in the reactor.) The data seem to indicate that 60 seconds may have been too long a period for the maximum production of hydrocarbons. The formation of the hydrocarbons should be a maximum at the time when a plateau of the extent of coal gasification is attained, and prolonged treatment probably allows the remaining H20 vapor to diffuse into the discharge zone, giving an adverse effect. It was also noticed that, at an initial H20 pressure of less than 12 mm, the hydrogen content of the products exceeded that which could possibly be derived from the stoichiometric amount of the H20 initially present. These results seem to indicate the following. The active hydrogen species formed in the Hq0 discharge participate in the reactions which lead to the formation of hydrocarbons from (some of) the species derived from the coal. This occurs despite the retarding effect of H20 on hydrocarbon formetion. (If the H20 pressure is too high, this latter effect decreases the hydrocarbon yield.) Presumebly, the coals when gasified supply enough CB species to allow hydro- carbons to be formed,even though the active oxygen species present react with some of the gaseous carbon and CH species. On the other hand, graphite produces negligible amounts of CH species in a H20-Ar discharge, and therefore cannot produce hydrocarbons since the reaction of the CO formed with the active hydrogen species is retarded by the H20 present. Lignite, with its high volatile matter content, was extensively gasified but gave a relatively low hydrocarbon yield, presumably due to the inhibition by its high oxygen content. For lignite, the production of COq was also higher in the R20-Ar discharge than in the Hq-Ar or Ar discharge. Again, the extent of gasification for chrysene was rather small.
- Page 390 and 391: . .. 386 9 * - r. Y 2 .' d a f' r.
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- Page 398 and 399: 394 The present method is to keep t
- Page 400 and 401: 396 ‘c erperature, while the pres
- Page 402 and 403: 2, '! ! Proximate Analysis, wt $ Mo
- Page 404 and 405: 0 IS 0 14 LL 9 013 e \ 3 b- m *- 01
- Page 406 and 407: 402 HYDROGEN CYANIDE PRODUCED FROM
- Page 408 and 409: 404 Before startup, the system is p
- Page 410 and 411: 4 OL. ' , I. . TesCs. With.Coals .o
- Page 412 and 413: Table 3.- Product Gas Analyses and
- Page 414 and 415: 410 BIBLIOGRAPHY 1. American Public
- Page 416 and 417: Figure 2. Enclosure surrounding hyd
- Page 418 and 419: 0 0 f v) C 0 u m I z 2 c 2 r d J w
- Page 420 and 421: 0. E c .4 7 .. .c . I ( - Low tempe
- Page 422 and 423: 418 cual. A mjor aa\;antage or' the
- Page 424 and 425: 420 Ir ?Y ? ? 9 9 9 pc rod n o c o
- Page 426 and 427: 422 Table 3. Room-texperature M'dss
- Page 428 and 429: 424 state, depending on the strengt
- Page 430 and 431: Table 4. Room-?;ergerature isomer s
- Page 432 and 433: I' 1.3 . /o 9 IO 9 6 a 425 F F 33 I
- Page 434 and 435: Brooks J.D. and Sternhell S. (1957)
- Page 436 and 437: (52) Gib3 T.C. and Greenwood N.N. (
- Page 438 and 439: 434 transducer vas then introduced
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- Page 444 and 445: 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 4
- Page 446 and 447: 442 CHEMICAL REACTIONS IN A CORONA
- Page 448 and 449: helium 444 CORONA REACTOR SYSTEM Fi
- Page 450 and 451: 446 The ultraviolet spectrum. for t
- Page 452 and 453: Biphenyl Fraction 448 The low molec
- Page 454 and 455: LUd The actual structural definitio
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- Page 458 and 459: ’. 454 Mechanism I The available
- Page 460 and 461: 456 , , . The relatively low yield
- Page 462 and 463: 458 h/lethylacetylene, allene and b
- Page 464 and 465: Introduction VAPOR PHASE DECOMPOSIT
- Page 466 and 467: 462 more efficient hydrogenation. T
- Page 468 and 469: 464 place in parallel with fragment
- Page 470 and 471: 466 P rl 0, k 7 rnI rn al k a I hl
- Page 472 and 473: 458 TABLE I. COMPOSI'IION OF GASEOU
- Page 474 and 475: REFERENCES 1. C. Hirayama and D. A.
- Page 476 and 477: i 472 Reciprocal Arc Enthalpy ,-> F
- Page 478 and 479: 474 be pumped down without altering
- Page 480 and 481: 476 Instead a hydrogen deficient fi
- Page 482 and 483: i 478
- Page 484 and 485: 480 FATTY ACIDS AND n-ALKANES IN GR
- Page 486 and 487: 482 TA5L,E 2. - Carbon number distr
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436<br />
yield is quite similar. The conversion <strong>of</strong> carbon to C2H2 for the high volatile<br />
bituminous coal (VM 5 39.2%) in table 2 is 9.2% in the H2-Ar discharge as compared<br />
to 12.5'1. in the Ar plasma for a coal <strong>of</strong> similar volatile matter content.<br />
TABLE 2. - Reactions <strong>of</strong> coal and related materials<br />
in microwave <strong>discharges</strong> <strong>of</strong> H? and Ar 1<br />
Pressure,<br />
Percent <strong>of</strong> c present as ,/<br />
Uaterial<br />
m<br />
H,, Ar<br />
Time, Yield x lo4, mole/g <strong>of</strong> solid<br />
sec H? clll C2H2 CO CO?<br />
Gasebus Gaseous<br />
products hydrocarbons<br />
hvab 22.7 2.3 60 63.9 4.7 31.1 21.1<br />
22.7 2.3 60 53.6 10.2 28.6 20.2<br />
23.4 2.4 60 12.5 4.5 27.0 23.6<br />
22.8 2.4 90 11 3,9 29.8 22.2<br />
21.8 2.3 105 L/ 4.8 21.0 ' 16.9<br />
21.9 2.3 110 11 3.6 20.0 16.0<br />
- 25.7 17 3.3 .1 1.2 7.1<br />
- 24.0 60 56.4 .9 13.4 23.0<br />
- 23.6 180 44.0 1.1 16.5 22.6<br />
lvb 23.8 2.5 34 1/ 4.1 15.5 7.3<br />
21.6 2.2 60 1/ 3.8 17.5 8.1<br />
- 23.5 60 15.3 .3 3.6 7.7<br />
Lignite 21.6 2.2 60 25.4 2.1 9.3 66.2<br />
22.6 2.3 180 22.9 2.1 7.7 80.3<br />
20.7 2.1 180 26.0 2.1 7.3 69.2<br />
- 24.7 32 50.4 .7 6.9 61.7<br />
- 23.0 60 18.4 .6 5.0 68.4<br />
Anthracite 21.6 2.2 60 11 4.2 8.3 4.0<br />
22.6 2.4 60 11 4.6 9.6 3.0<br />
- 24.0 60 .3 trace trace 2.0<br />
Chrysene 22.7 2.4 10 11 6.5 12.8 2.0<br />
20.0 2.0 30 11 10.4 5.8 trace<br />
- 22.0 30 lz.6 .8 2.6 trace<br />
Graphite 22.4 2.3 60 11 3.5 2.5 trace<br />
22.6 2.4 60 11 3.4 1.8 trace<br />
11 Net decrease <strong>of</strong> hydrogen was indicated.<br />
0.2<br />
.2<br />
.4<br />
.2<br />
.2<br />
.2<br />
.1<br />
.2<br />
.2<br />
.1<br />
.1<br />
trace<br />
3.5<br />
1.8<br />
1.7<br />
3.2<br />
3.2<br />
trace<br />
trace<br />
.1<br />
trace<br />
trace<br />
trace<br />
trace<br />
trace<br />
13.6<br />
13.1<br />
12.8<br />
13.1<br />
9.9<br />
9.4<br />
1.5<br />
7.7<br />
8.7<br />
6.1<br />
6.7<br />
2.1<br />
16.7<br />
18.3 '<br />
16.1<br />
14.1<br />
15.1<br />
3.6<br />
3.9<br />
.3<br />
4.6<br />
3.4<br />
.9<br />
1.2<br />
1.0<br />
I<br />
10.4<br />
10.3 \<br />
9.4<br />
9.9 4<br />
7.4<br />
7.0<br />
-4 \<br />
4.3<br />
5.3 '<br />
5.1 \<br />
5.6<br />
1.1<br />
4.1<br />
3.3<br />
::: /<br />
3.1<br />
3.4 ~<br />
4.4<br />
3.4 \<br />
.9 I<br />
1.2<br />
1.0 \<br />
Solid Product I<br />
The solid product obtained from coal is brownish and is similar to that usually<br />
observed from the thermal treatment <strong>of</strong> coal. Uo appreciable amount <strong>of</strong> solid product<br />
was formed from anthracite or from lignite. Though the extent <strong>of</strong> the gasification<br />
for the chrysene was not appreciable, the original white powder was instantaneously<br />
converted to a broun solid upon the initiation <strong>of</strong> both <strong>discharges</strong>. The infrared <<br />
spectra <strong>of</strong> the solid product and the residual char obtained from the high volatile<br />
bituminous coal in the H2-Ar discharge showed the usual aliphatic C-R bands and<br />
some weak aromatic bands which are typical <strong>of</strong> pitch and coal.<br />
3<br />
* 7<br />
1<br />
Effect <strong>of</strong> Cooling by Liquid Nitrogen<br />
Since the indications are that the wnter formed can retard the hydrocarbon formation<br />
and that the hydrocarbons produced may undergo further destructive reactions, it can<br />
be expected that a rapid quenching <strong>of</strong> the primary products should give a pronounced<br />
effect on the result. Experiments were carried out in a reactor consisting <strong>of</strong> the<br />
i t