work so far—namely, that the potential resource is too large to ignore. It's possible that enough private funding can be had to continue some exploratory work. But it would seem that sooner or later the federal government will have to make the major contribution. Joseph Haggin, Chicago
Two-step COthane process uses waste carbon monoxide to make methane Vent
Disproportionation step Carbon monoxide
Preheater
Process taps energy of waste carbon monoxide A 1976 survey indicated that as much as 24 million tons per year of dilute carbon monoxide was being flared at industrial locations in the U.S., most of it from steel mills and petroleum refineries. The energy equivalent was about 570 million cu ft per day of natural gas. There was no economical way to utilize this large potential source of heat. Now a process has been tested that will convert the dilute carbon monoxide streams to methane and carbon dioxide. Called COthane, the process has been developed at Union Carbide's Tarrytown, N.Y., technical center. Carbide's Albert C. Frost described the process for the summer national meeting of the American Institute of Chemical Engineers in Detroit last week! The COthane process evolved from the observation that carbon monoxide rapidly disproportionates on a nickel catalyst to carbon dioxide and active carbon. The active carbon further reacts to form equimolar quantities of methane and carbon dioxide. According to Frost, this observation was the basis for subsequent laboratory-scale process development unit tests of the two-step process. In the first step, waste gas is pretreated and passed through a reactor containing a nickel or cobalt catalyst bed. At temperatures of 270 to 300 °C the following disproportionation occurs: 4CO ^ 2 C 0 2 + 2 C This reaction proceeds until the catalyst is loaded with the active carbon. The waste gas feed is then diverted to a second reactor that has been stripped of carbon. Low-pressure steam is then introduced into the first reactor where it reacts with the active carbon according to the reaction: 2 C + 2H 2 0 ^ CH4 + C 0 2 Eventually the carbon is consumed and the roles of the reactors are reversed. Continued alternation of the
Dowtherm condensate return Steaming step
®— 140psig pipelinequality methane
150 psig steam Preheater
r Dehydrator
Carbon dioxide removal
reactors provides continuous operation. The net reaction is: 4 CO + 2H 2 0 ^ CH 4 + 3 C 0 2 The wet carbon dioxide/methane stream is stripped of carbon dioxide and water, which are vented. The methane is fed to a local natural gas distribution system. Feed pretreatment depends on the source of the carbon monoxide. Reactive diluents, such as oxygen, react with the active carbon and are undesirable. Catalyst poisons, such as hydrogen sulfide, are also removed. A small amount of "inactive" carbon appears to be deposited during each cycle and is purged periodically. About 79% of the gross energy available in the carbon monoxide appears in the product methane. The largest single source of off-gas carbon monoxide is blast furnace exhaust, but this source is declining as antipollution measures are being implemented. However, the potential of the COthane process for upgrading exhaust from in-situ coal gasification could more than offset the decline in blast-furnace exhaust. Other major sources of carbon monoxide include basic oxygen furnaces, gray iron casting, aluminum production, and petroleum refining. Methane production costs from blast-furnace exhaust have been estimated at $5.78 per million Btu; for
Tubular reactor
\ Dowtherm condensate return
BOF off-gas, $7.11 per million Btu; and for carbon-black off-gas $8.10 per million Btu. These costs are considerably higher than the price of natural gas, which presently is running at $2.00 to $4.00 per million Btu. However, Carbide believes that the cost gap will narrow with time and that the COthane process may be a good way to minimize losses associated with exhaust gas cleanup mandated by the Environmental Protection Agency. •
Energy industry to be major hydrogen user An assessment of world hydrogen markets through the year 2025 has been completed by the International Energy Agency. Most of the consumption, it shows, will be for synfuels production and conventional chemicals production. IEA had been interested in promoting hydrogen as an energy carrier, but the economics don't favor development of this application for the period of the study, except in highly localized circumstances. Contributing to the two-year stildy are mainly countries of Western Europe, North America, and Japan. A composite report was prepared from national estimates by a group headed Aug. 24, 1981 C&EN
21
Technology
Study projects hydrogen consumption through 2025 Joules X 1 0 1 5
Belgium
Canada
20
107
136
95
—
58 85
20
202
279
1985 Nonenergy Energy Indirect Direct
—
Subtotal 2005 Nonenergy
Germany
Japan
Netherlands
Sweden
65
5
15 10
3-7
100-110
90
130-170
65
100-110
—
1170
470
41-45
1.8
1200
1940
8-14
1.8
1,800-2,000
2,400-2,600
14
4,600-5,200 900-1,500
6,000-6,600 1,200-2,000
16
7,300-8,700
9,600-11,200
3,000-4,000
3,700-4,800
15,000-20,000 2,400-4,200 20,000-28,000
17,000-20,000 3,000-6,000 24,000-33,000
220
40
Subtotal
60
200 4 344
940 260 1420
220-260
265
20-40
180
260
190-270
—
18-25
40-50 30 90-120
340 7 520
1800 400 2500
_ — —
3-21 68-230 89-280
180 20
730
640 130
140
90
Total
—
20
_
1.8
USA
—
33
Energy Indirect Direct
—
Switzerland
4-22 41-130 53-166
2025 Nonenergy Energy Indirect Direct Subtotal
___ 0-1100 190-1300
1.8
58 60
Note: 1 Btu = 1054.8 Joules.
by Wim van Deelen of the Commission of European Communities. A summary of the study was presented last week in Detroit to the American Institute of Chemical Engineers by William J. D. Escher of EschenFoster Technology Associates, St. Johns, Mich., who was a consultant for Jet Propulsion Laboratory, which represented the U.S. in the study. Three major categories of consumption considered by the report are nonenergy uses, such as chemical reactants and metallurgical reductants; direct energy uses, such as a fuel gas; and indirect energy uses, such as production of synthetic fuels and operation of refineries. In the next 45 years, according to the study, hydrogen consumption is projected to grow worldwide by about 7% per year on average. The greatest volume of hydrogen is expected to be consumed in the indirect energy sector, but the greatest percentage increase is expected to be in direct consumption. Slowest growth is expected to be in those countries, such as Canada, with large fossil fuel resources. The usual variety of barriers and stimuli have been cited as influencing the future growth of hydrogen consumption, including government policies and competition from established energy sources. By the year 2025,85% of hydrogen production will be used in the energy industry. About 16% will be consumed as direct energy and 69% for refinery operation and synfuels production. Proponents of the "hydrogen economy" can take 22
C&ENAug. 24, 1981
some comfort in the increased consumption of direct energy hydrogen, but fossil fuels will still dominate the energy industry, with oil and coal being the major carbon sources. Hydrogen production in the U.S. is projected to grow about 7.6% per year with about 65% of it going into synfuels production, probably for low-
and medium-Btu gases. The hydrogen probably will be derived, says the study, from coal gasification with steam and/or electrochemical and thermochemical splitting of water. Switzerland and Sweden may become the biggest per-capita consumers of hydrogen for heating during the next 45 years. •
Scintillation detector unit to be used in particle studies Barbara Gorby, a physicist at Harshaw Chemical Co., Cleveland, examines a 6-foot diameter detector unit designed by Washington University, built by Harshaw, and slated for use at Oak Ridge National Laboratory. The unit, with 72 thallium-activated sodium iodide scintillation crystals mounted individually on photomultiplier tubes, will become a major component in a spin spectrometer. The device will be used to study subatomic structure. Because of the spherical configuration of its chamber, the "crystal ball" makes it possible to detect gamma rays, neutrons, and charged particles traveling in all directions from an event taking place in the chamber.
