Envlron. Sci. Technol. 1984, 18, 600-603
Tompkins, M. R.; Morris, C. L. Lawrence Livermore National Laboratory, Livermore, CA, personal communications, 1980. Smith, J. W.; Young, N. B.; Lawlor, R. L. Anal. Chem. 1964,
(25) Sklarew, D. S. Geochim. Cosmochim. Acta 1979, 43, 1949-1958. (26) Sklarew, D. S.; Nagy, B. Precambrian Res. 1981,15,97-111. (27) Willey, C.; Pelroy, R. A,; Stewart, D. L. In “Polynuclear
36, 618.
Aromatic Hydrocarbons: Chemistry and Biological Effects”; Cooke, W. M.; Dennis, A. J., Ed.; Battelle Press: Columbus, OH, 1982. (28) Colorado Air Quality Control Commission Regulation No. 6-IV C3. (29) Fruchter, J. S.; Wilkerson, C. L.; Sklarew, D. S.; Olsen, K. B.; Ondov, J. M. In “Oil Shale: The Environmental Challenges, Part 111”;Petersen, K. K., Ed.; Colorado School of Mines Press: Golden, CO, 1983; pp 139-164. (30) Lorton, G. A. 1980, EPRI EM-1333 Project 1041-5 Final Report.
Perterson, G. Los Alamoa National Laboratory, Los Alamos, NM, personal communication, 1983. Burnham, A. K. 1981, UCID-19093. Gattow, G.; Behrendt, W. In “Topics in Sulfur Chemistry”; Senning, A., Ed.; Georg Threme Publishers: Stuttgart,1977; VOl. 2. Ho, T. Y.; Rogers, M. A.; Drushel, H. V.; Koons, C. B. Am. Assoc. Pet. Geol. Bull. 1974,50, 2338-2348. Ryland, L. B.; Tamele, M. W. In “The Analytical Chemistry of Sulfur and Its Compounds-Part I”; Karchmer, J. H., Ed.; Wiley-Interscience: New York, 1970; pp 465-520. Khare, B. N.; Sagan,C.; Bandurski, E. L.; Nagy, B. Science (Washington, D.C.) 1978,199, 1199-1201. Davis, R. E. In “InorganicSulphur Chemistry”;Nickless, E., Ed.; Elsevier: Amsterdam, 1968; pp 85-136. Burnham, A. K.; Bey, N. K.; Koskinas, G. J. ACS Symp. Ser. 1981, No. 163.
Received for review July 5,1983. Revised manuscript received December 5,1983. Accepted January 25,1984. This project was supported by the US.Department of Energy, Office of Health and Environmental Research, under Contract DE-AC06-76RLO 1830.
Trace Nitrogen-Containing Species in the Offgas from Two Oil Shale Retorting Processes Deborah S. Sklarew” and Deborah J. Hayes? Pacific Northwest Laboratories, Richland, Washington 99352
Five organic nitrogen species were identified in the offgas from two different retorting processes, a modified in situ process and an aboveground process. Hydrogen cyanide, acetonitrile, acrylonitrile, propionitrile, and isobutyronitrile were determined by gas chromatography combined with a nitrogen-phosphorus detector. Seven other nitrogen species have been tentatively identified in the offgas a t one of the in situ retorts. The low molecular weight organic nitrogen species appear to be predominantly nitriles; low molecular weight aliphatic amines do not appear to be present. Possible reaction mechanisms were considered. The nitriles were present in amounts on the order of tens of ppm which was -11-290 of the gas-phase ammonia nitrogen concentration in the offgas. Most of the nitrogen species except hydrogen cyanide appear to be reasonably stable, at least qualitatively, for a period of several months in Teflon-lined stainless steel bombs. Introduction The nonhydrocarbon trace species in the offgases from oil shale retorts could cause significant health and environmental impacts in an expanded oil shale industry if not properly controlled. Knowledge of the types and amounts of species present will help to determine the mitigation procedures necessary to decrease their impact and will also be a starting point for studying the conditions leading to their formation. In a related study (1) the trace sulfur present in retort offgases from two retorting technologies were discussed. In this paper, the organic nitrogen species (i.e., those other than NH,, NO,, and N,) in the retort offgases from the same technologies are identified. These nitrogen compounds are important because of their toxicity and because of their potential contributions to NO, stack emissions and to fugitive emissions. Since NO, is considered to be a Present address:, Battelle-Houston, Houston, TX 77027. 600
Envlron. Scl. Technol., Vol.
18, No. 8, 1984
criteria pollutant by the EPA, any contributions to its formation must be taken into account in a commercial plant in determining retort and mitigation conditions. The retorts from which gases were sampled included Rio Blanco’s vertical modified in situ Retorts 0 and 1and the Paraho direct-heated aboveground retort. Because the retorts were in the pilot plant stage, effluents are not necessarily representative of those which will be obtained in future commercial operations. In addition, the offgases studied were untreated and, therefore, again, are not necessarily representative of the emissions that will be produced by an oil shale industry. However, the results do indicate the types of problems that the commercial industry will face. Analytical data about trace nitrogen species in retort offgases appear to be even more scarce than the trace sulfur species data. One report indicates that hydrogen cyanide has been measured a t the demister outlet at Geokinetics (Z), but information about other trace nitrogen species here or at other retorts appears to be lacking in the literature. Several studies are available regarding NH, concentrations in retort offgases. For example, NH3 concentrations of 6300 and 850 ppm have been measured a t the Paraho direct-heated retort in Nov 1977 and a t Rio Blanco Retort 0 in July 1980, respectively (3). We report here the identification of five non-NH3 nitrogen species and the tentative identification of nine other organic nitrogen species in the retort gases from two different oil shale retorts. Most of the nitrogen species had not previously been identified in oil shale retort gases. Experimental Section Sampling trips and methods are discussed in ref 1. Analysis was accomplished on site a t the Rio Blanco Retorts 0 and 1. All other samples were grab samples analyzed in the laboratory usually several months, but in one case several years, after collection. These samples were taken in Teflon-coated stainless steel bombs a t approximately ambient pressure from Rio Blanco’s Retort 0 (trips
0013-936X/84/0918-0600$01.50/0
0 1984 American Chemical Society
CH,Cl
Table I. Permeation Tubes and Gas Standards at Retort l
I
permeation tubesa
gas cylindersb
methylamine, 110 ppm ethylamine, 35 ppm dimethylamine, 70 ppm HCN, 50 ppm acrylonitrile, 54 ppm
methylamine, 102 ppm HCN, 109 ppm
Permeation tubes were supplied and certified by Vici Metronics, Santa Clara, CA. Concentrations listed are based on the permeation rate at the temperature used for certification, atmospheric pressure, and 175 mL/min. bGas cylinders were supplied and certified by Matheson. Nitrogen species were diluted in N2. Concentrations in volume uum. C
6p"
I
120.
I
10
I
I
I
20
30
I
40
50
MINUTES
Table 11. Nitrogen Species (NPD)
Figure 1. Gas chromatogram of nitrogen species in undiluted offgas. Overlap of nibogen and hydrocarbon species on a Porapak QS COlUt'nn.
2 and 3) (see ref l),the Sept 1980 Paraho retort, and another Paraho retort from Nov 16, 1977. The bomb samples were shipped within a day of collection and stored in the laboratory a t 4 OC. The field analyses were both qualitative and semiquantitative; the grab samples were analyzed qualitatively. Nitrogen and hydrocarbon species were analyzed by gas chromatography (HP5840A) using a nitrogen-phosphorus detector (NPD) and flame ionization detector (FID), respectively. Gas flows were used as described in the HP5840 GC manual. Selectivity of the NPD was excellent under these conditions; i.e., percent levels of methane were not detected. Glass, 6 f t X 2 mm i.d., columns were connected directly to the injection port for on-column injections. Both Porapak QS and Chromosorb 103 gave good separations of the lower molecular weight nitrogen species present. The Chromosorb 103 column was also used for higher boiling components since its upper temperature limit is significantly higher than that of Porapak QS. Hydrocarbons were evaluated on both columns (1). The temperature program for the Porapak QS column was initiated a t 60 OC, held isothermal for 6 min, and then ramped a t 6 "C/min to 180 "C where it was held for -40 min. The temperature program for the Chromosorb 103 column was generally started a t 130 OC, held for 10 min, then programmed a t 6 OC/min to 250 "C,and held isothermal for ,- 10 min. These program rates allowed separation of many of the nitrogen species from the more predominant hydrocarbons especially on the Porapak QS column (Figure 1). The Chromosorb 103 program rate was modified to an initial temperature of 100 OC for improved separation of some of the lowest molecular weight nitrogen species. Four types of standards were used to identify and quantitate the samples: certified permeation tubes, certified gas standards, liquid solutions, and vapors above pure liquids (the last used for qualitative analysis only). Table I lists the nitrogen permeation tubes and gas standards available at Retort 1. All liquid nitrogen species were diluted in acetone. Bomb samples were also analyzed in the lab by GC-MS (HP5982) in an attempt to confirm identifications. A gas-tight syringe was used for retort gas and standard gas sampling. Precautions were taken so that sampling was conducted a t close to atmospheric pressure. However, this is not as accurate as using a gas sampling loop, so data are considered to be semiquantitative. Results and Discussion Five organic nitrogen species have been identified in the retort gas a t Rio Blanco Retort 1 by GC-NPD: aceto-
compound analyzed hydrogen cyanide acetonitrile acrylonitrile propionitrile isobutyronitrile pyrrole or pyridine' ?butenenitriled ?pentanenitriled pyrrolidine benzylamine N-methylaniline o-toluidine N,N-diethylaniline
in Rio Blanco Retort 1 retort gas'
X X X X X X ? ? ? ? ? ? ?
method of standard identification, GC ChromoPorasorb 103 pak QS
X X X X X X n.aSd n.a. b b b b b
b
X b X X X n.a. n.a. X X X
x X
a Detection
limit
