Gas identity analysis by differential mass

Abstract

A scale and container of known volume are used to determine the differential mass of an unknown gas compared to air. The differential mass of the unknown gas is compared to known differential masses of possible gases and the identity of the unknown gas is determined.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

not Applicable

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

The invention relates to a method for determining the identity of an unknown gas, by first identifying the density of the gas. Gases are usually identified by means of chromatography which is both costly and time consuming.

BRIEF SUMMARY OF THE INVENTION

It is the object of the invention to determine the identity of an unknown gas (typically nitrogen). The density of the unknown gas is determined by weighing a known volume and comparing it to the established weight of known gases at that volume. This method is preferable to existing methods because it reduces the expense of the alternative apparatus and training.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Not Applicable

DETAILED DESCRIPTIONS OF THE INVENTION

The weight of the unknown gas is determined by first weighing an open mouthed container of known volume filled with air at atmospheric pressure and ambient temperature. The scale is then set at zero. Then the unknown gas is flowed into the container displacing the air. The container weight is then taken to determine the differential mass of the unknown gas in the container. The differential mass is compared to Table 1, and the gas is preliminarily identified. Certain possible gases are excluded from consideration by their chemical properties. For example, in the case of nitrogen:

• • Carbon monoxide is excluded because a specific chemical test can be performed to determine the carbon monoxide concentration if carbon monoxide is suspected of being present.
  • Any odorous gases (ethylene, etc.) are excluded because an odor test (organoleptic) can be performed if those gases are suspected of being present.

All other gases have densities which are significantly different from nitrogen.

TABLE 1
Differential Mass of Known Gases
				N2	N2
	Molecular			Delta	Delta
Gas	Weight	g/liter	g/2 liter	2 L	1 L
Hydrogen	2.0159	0.089	0.178	−2.301	−1.150
Helium	4.0026	0.177	0.354	−2.125	−1.062
Deuterium	4.032	0.178	0.357	−2.122	−1.061
Methane	16.043	0.710	1.420	−1.059	−0.530
Anhydrous Ammonia	17.031	0.754	1.507	−0.972	−0.486
Water	18.02	0.797	1.595	−0.884	−0.442
Neon	20.183	0.893	1.786	−0.693	−0.346
Acetylene	26.038	1.152	2.304	−0.175	−0.087
Hydrogen Cyanide	27.03	1.196	2.392	−0.087	−0.043
Carbon Monoxide	28.0104	1.239	2.479	0.000	0.000
Nitrogen	28.0134	1.240	2.479	0.000	0.000
Ethylene	28.054	1.241	2.483	0.004	0.002
Air	28.96	1.281	2.563	0.084	0.042
Nitric Oxide	30.06	1.330	2.660	0.181	0.091
Ethane	30.07	1.331	2.661	0.182	0.091
Monomethylamine	31.058	1.374	2.748	0.269	0.135
Oxygen	32	1.416	2.832	0.353	0.176
Methanol	32.042	1.418	2.836	0.357	0.178
Silane	32.112	1.421	2.842	0.363	0.181
Phosphine	34	1.504	3.009	0.530	0.265
Hydrogen Sulfide	34.08	1.508	3.016	0.537	0.268
Hydrogen Chloride	36.461	1.613	3.227	0.748	0.374
Argon	39.948	1.768	3.535	1.056	0.528
Argon, UHP	39.948	1.768	3.535	1.056	0.528
Allene (Propadiene)	40.065	1.773	3.546	1.067	0.533
Methyl Acetylene	40.07	1.773	3.546	1.067	0.534
Propylene	42.079	1.862	3.724	1.245	0.622
Cyclopropane	42.08	1.862	3.724	1.245	0.622
Nitrous Oxide	44.01	1.947	3.895	1.416	0.708
Carbon Dioxide	44.011	1.947	3.895	1.416	0.708
Ethylene Oxide	44.053	1.949	3.898	1.419	0.710
Propane	44.11	1.952	3.904	1.425	0.712
Dimethylamine	45.085	1.995	3.990	1.511	0.755
Monoethylamine	45.085	1.995	3.990	1.511	0.755
Nitrogen Dioxide	46.01	2.036	4.072	1.593	0.796
Dimethylether	46.069	2.038	4.077	1.598	0.799
Ethanol	46.07	2.038	4.077	1.598	0.799
Methyl Chloride	50.49	2.234	4.468	1.989	0.995
Cyanogen	52.036	2.302	4.605	2.126	1.063
1,3-Butadiene	54.092	2.393	4.787	2.308	1.154
1-Butene	56.108	2.483	4.965	2.486	1.243
cis-2-Butene	56.108	2.483	4.965	2.486	1.243
Isobutylene	56.11	2.483	4.965	2.486	1.243
Trans-2-Butene	56.12	2.483	4.966	2.487	1.244
Acetone	58.08	2.570	5.140	2.661	1.330
Butane	58.124	2.572	5.144	2.665	1.332
Isobutane	58.124	2.572	5.144	2.665	1.332
Trimethylamine	59.11	2.615	5.231	2.752	1.376
Carbonyl Sulfide	60.07	2.658	5.316	2.837	1.418
Vinyl Chloride	62.5	2.765	5.531	3.052	1.526
Sulfur Dioxide	64.063	2.835	5.669	3.190	1.595
Ethyl Chloride	64.52	2.855	5.710	3.231	1.615
Carbonyl Fluoride	66.007	2.921	5.841	3.362	1.681
Boron Trifluoride	67.805	3.000	6.000	3.521	1.761
Isoprene	68.119	3.014	6.028	3.549	1.775
Cyclopentane	70.135	3.103	6.207	3.728	1.864
1-Pentene	70.135	3.103	6.207	3.728	1.864
Chlorine	70.906	3.137	6.275	3.796	1.898
2,2 Dimethylpropane	72.151	3.193	6.385	3.906	1.953
(Neopentane)
n-Pentane	72.151	3.193	6.385	3.906	1.953
iso-Pentane	72.151	3.193	6.385	3.906	1.953
Arsine	77.946	3.449	6.898	4.419	2.209
Benzene	78.114	3.456	6.913	4.434	2.217
Hydrogen Bromide	80.912	3.580	7.160	4.681	2.341
Hydrogen Selenide	80.976	3.583	7.166	4.687	2.344
Krypton	83.8	3.708	7.416	4.937	2.468
1-Hexene	84.16	3.724	7.448	4.969	2.484
Methylcyclopentane	84.162	3.724	7.448	4.969	2.484
Cyclohexane	84.162	3.724	7.448	4.969	2.484
Hexane	86.178	3.813	7.626	5.147	2.574
2,3-Dimethylbutane	86.178	3.813	7.626	5.147	2.574
2-Methylpentane	86.178	3.813	7.626	5.147	2.574
3-Methylpentane	86.178	3.813	7.626	5.147	2.574
Neohexane	86.178	3.813	7.626	5.147	2.574
Chlorodifluoromethane	86.5	3.827	7.655	5.176	2.588
(R-22)
Tetrafluoromethane	88.01	3.894	7.788	5.309	2.655
Toluene	92.141	4.077	8.154	5.675	2.838
Methylcyclohexane	98.189	4.345	8.689	6.210	3.105
Phosgene	98.92	4.377	8.754	6.275	3.137
n-Heptane	100.205	4.434	8.868	6.389	3.194
2-Methylhexane	100.205	4.434	8.868	6.389	3.194
3-Methylhexane	100.205	4.434	8.868	6.389	3.194
3-Ethylpentane	100.205	4.434	8.868	6.389	3.194
2,2-Dimethylpentane	100.205	4.434	8.868	6.389	3.194
2,4-Dimethylpentane	100.205	4.434	8.868	6.389	3.194
3,3-Dimethylpentane	100.205	4.434	8.868	6.389	3.194
Dichlorosilane	101.01	4.469	8.939	6.460	3.230
Silicon Tetrafluoride	104.08	4.605	9.211	6.732	3.366
Styrene	104.152	4.608	9.217	6.738	3.369
o-Xylene	106.168	4.698	9.395	6.916	3.458
p-Xylene	106.168	4.698	9.395	6.916	3.458
Ethylbenzene	106.168	4.698	9.395	6.916	3.458
m-Xylene	106.17	4.698	9.396	6.917	3.458
Octane	114.232	5.055	10.109	7.630	3.815
Isooctane	114.232	5.055	10.109	7.630	3.815
Boron Trichloride	117.17	5.185	10.369	7.890	3.945
Isopropylbenzene	120.195	5.318	10.637	8.158	4.079
n-Nonane	128.256	5.675	11.350	8.871	4.436
Xenon	131.3	5.810	11.619	9.140	4.570
n-Decane	142.286	6.296	12.592	10.113	5.056
Sulfur Hexafluoride	146.054	6.463	12.925	10.446	5.223

Claims

1. A method for identifying a gas by means of first determining the differential mass of a known volume of the unknown gas and comparing the result to the established differential mass of known gases.

2. A method as in claim 1 wherein the weight of the fixed volume container is nulled by filling with air at atmospheric pressure and ambient temperature, observing the indicated weight and taring the scale indication to zero.

3. A method as in claim 1 wherein an unknown gas is flowed into an empty container displacing the air.

4. A method as in claim 1 wherein the container weight is then taken to determine the differential mass of the unknown gas in the container compared to the weight of the container filled with air at atmospheric pressure and ambient temperature.

5. A method as in claim 1 wherein the differential mass of the unknown gas is compared known differential masses of possible gases.

6. A method as in claim 1 wherein the certain possible gases are excluded from consideration by their chemical properties and the identity of the unknown gas is concluded.