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growth. Under such an environment, rather than a policy of end-use controls, the petroleum industry feels assured that it can meet the challenges that lie ahead. This is a belief apparently shared by the Department of the Interior which said in its "appraisal" last year

The data developed by this study reveal an industry that is healthy and vigorous and capable of meeting the requirements that will be placed upon it in the foreseeable future ***. It is evident that the petroleum industry has the finan

cial and technological capability to accomplish it.

Question 2: Realistically, what are the near term prospects for an economically competitive replacement for tetraethyl lead in gasoline? Answer: On a realistic basis, the prospects for the discovery of an economically competitive replacement for lead antiknock compounds are very slim.

An extensive search for such a compound has been carried out on a multimillion-dollar-per-year scale by the antiknock manufacturers, petroleum refiners, and chemical companies since World War I. To date, this vast research effort has not produced a suitable alternative antiknock compound. The major technical requirements for such a compound are formidable. They are:

1. High antiknock effectiveness in a broad range of hydrocarbon types under a wide variety of engine operating conditions. 2. High solubility in a wide range of hydrocarbon types.

3. Negligible solubility in water which is present to some degree in all fuel systems.

4. Volatility characteristics permitting relatively uniform distribution to the various cylinders of the internal combustion engine.

5. Sufficient chemical stability to permit normal handling and storage both in the concentrated form and when blended with gasoline.

6. The ability to be consumed in typical engines without causing significant engine durability problems.

Research for new antiknocks will, of course, continue. As new chemistry develops through basic research in universities, industry, and Government laboratories the new chemical compounds resulting from such research will be investigated as possible antiknocks. But, based on the present state of the art, the chances appear to be poor for a near term replacement for lead antiknocks.

Question 3: How does the present crude oil import policy affect the sulfur content of fuels for sale in the United States?

Answer: If the present crude oil import policy were relaxed, U.S. refiners would probably process more crude oil from the Middle East and from South America. Since these imported crudes generally contain a higher sulfur content and are heavier than domestic crudes, increased volumes of residual fuel with a higher sulfur content would be produced. It should be noted that among the imported crudes, Venezuela crudes contain somewhat less sulfur than Eastern Hemisphere production although they are generally higher than U.S. crudes. North African crudes are relatively low in sulfur, and to the extent they might be brought to the U.S. east coast refineries, they would tend to drop the sulfur content of residual fuels.

COMMENTS ON INDUSTRYWIDE, INDUSTRY-BY-INDUSTRY EFFLUENT

STANDARDS

1. Industrywide, industry-by-industry, effluent standards would be inconsistent with the current Federal Water Pollution Control Act which requires the establishment of water quality criteria in receiving streams to protect the legitimate uses of each section of major river basins.

2. Since all receiving waters cannot be used for all purposes and their capacity to assimilate treated wastes are highly variable, there should be no uniform effluent requirements for all industries. This would impose an unjustified burden on companies discharging effluents into a large stream with limited water uses and understate the requirements for a plant operating on low-volume streams of high quality.

3. It is equally obvious, however, that the establishment of receiving water quality criteria alone will not be sufficient to guide industries and municipalities as to the effluent targets that must be met to achieve the goals for the particular receiving stream. Ultimately, the total allowable pollution load on a particular stream must be established and allocated back to industrial and municipal dischargers. 4. The imposition of nationwide effluent standards would result in an unnecessary expense to the consuming public. The availability of water for industrial use is only one of many factors in an industrial operation. If we are going to legislate that this factor is exactly the same for everyone, everywhere, whether local conditions require it or not, then we might as well legislate to equalize all the other factors such as labor costs, transportation, availability of raw materials, etc.

5. In the past it has been the prerogative of the individual plant to select treating methods to satisfy a condition in a stream at the most economical cost. Since stream conditions and flow vary for each individual stream and plant effluent volumes vary, the setting of a common effluent standard would result in unnecessary increased costs for many, but not all plants.

6. In this connection, industry should properly provide technical guidance to regulatory authorities in formulating programs for individual plant waste reduction. Industry is in the best position to assist in developing an equitable basis for allocating allowable waste loads among plants discharging into a particular receiving stream.

7. With respect to air pollution, the above principles apply as well to control of emissions to the atmosphere. Air quality criteria should be established as targets to be achieved. Individual air basins should then be studied from a meteorological, topographic, and population basis. An inventory of all emissions should be conducted and an equitable rollback of objectionable levels of pollutants prescribed where necessary.

8. During the course of the hearings, the question concerning the establishment of industrywide standards was raised a number of times. This concept was discussed by Dr. Abel Wolman during his summation of the hearings. We concur most wholeheartedly with his conclusion that industrywide standards would not be practical.

RESPONSES TO QUESTIONS OF THE SUBCOMMITTEE ON SCIENCE, RESEARCH, AND DEVELOPMENT BY DR. ARTHUR M. BUECHE, GENERAL ELECTRIC Co.

Question 1: Is the military space R. & D. on fuel cells and batteries compatible with specifications for these devices in transportation, or will special additional work be necessary?

Answer: The contribution to commercial fuel cells by space R. & D. is mainly the establishment of a technical base and a competent electrochemical development and production organization that can be reoriented to commercial fuel cell development after completion of space R. & D. There is the possibility of using a small portion of the materials and components, but modification is almost always necessary. The contribution to commercial fuel cells by military R. & D. is greater than that from space R. & D. since the former R. & D. is usually oriented to air instead of oxygen operation. However, military R. & D. is usually directed toward fuel cells that use logistically available fuels, which are generally very "dirty" (containing lead or large amounts of sulfur). Also, military fuel cells must operate in a water-conservative manner. As a result of this required complexity, the fuel cells developed will be too expensive to penetrate the pricesensitive, transportation industry.

Specific R. & D. funds oriented toward power systems utilizing fuel cells to meet the different and less complex requirements of the commerical transportation industry will have to be spent by private industry or the Government before any significant strides can be made for commercial transportation. A substantial service test program similar to the military and space programs will be necessary to prove applicability to commercial vehicular systems.

(For additional information, please note the following article, "Fuel Cells and Fuel Batteries. An Engineering View.")

FUEL CELLS AND FUEL BATTERIES-AN ENGINEERING VIEW

(By H. A. Liebhafsky, General Electric Research and Development Center, Schenectady, N.Y.)

This is a welcome opportunity to attempt a paper on fuel cells primarily for electrical and electronic engineers, who may some day be joined by a new kind of engineer-the electrochemical engineer-if fuel batteries attain their expected usefulness. The kind of problems the new engineer will have to face are implicit in the questions and answers below.

WHAT IS A FUEL CELL? A FUEL BATTERY?

Fuel in its classic sense ought to be the key word in these definitions. Fuel cells and fuel batteries ought to react conventional fuels by which we mean the fossil fuels and substances readily derived therefrom) electrochemically with oxygen, preferably from air. A fuel cell thus is an electrochemical cell in which energy from such a reaction is converted directly and usefully into low-voltage direct-current electrical energy. Fuel cells electrically connected (in series, parallel, or series-parallel) make fuel batteries. The most common type of fuel cell is shown in Figure 1.

These definitions are more important than they seem. Though restrictive to make the subject manageable, they still include devices of great diversity. Fuel as used here excludes important substances often included, such as atomic "fuels" (e.g. uranium) and metals such as zinc or sodium (1).

The words directly and usefully imply that the device has an anode at which fuel is oxidized and a cathode at which oxygen is reduced; and that the conversion proceeds at voltages not greatly below the maximum possible, and at reasonably high current densities. Low-voltage and direct-current are important to the electrical engineer, who knows of course that electrical energy of this kind, although different from that ordinarily generated and transmitted, is of greatest importance to the electrochemical industry.

The reaction between conventional fuels and oxygen liberates only enough energy to give us about 1 volt per cell under ideal conditions. As Figure 1 shows, electrochemical reactions normally generate direct current. Schemes have been proposed to produce what has been loosely called alternating current from fuel cells, but the electrical engineer need not concern himself with such cells in the foreseeable future.

WHAT ARE THE IMPORTANT CONVENTIONAL FUELS?

In order of decreasing reactivity: hydrogen (in a class by itself); compromise fuels; and hydrocarbons.

Hydrogen belongs by itself because it is simple and highly reactive, the first characteristic probably being responsible for the second. When hydrogen reacts at an anode, it loses only one electron per atom and forms simple products. This probably explains why hydrogen can give us high current densities (amps/sq. ft. of geometric electrode surface) with minimum loss of voltage from the theoretical. Current density and rate of electrochemical reaction

are proportional.

Hydrogen has had a dominant position from the first in the fuel-cell field (see Figure 2), and hydrogen fuel cells and fuel batteries will be emphasized in this article. Hydrogen has serious disadvantages, among which only high cost and difficulties in handling and storage need be mentioned here. Because of these disadvantages, we must look to other fuels for the future.

The hydrocarbons, especially the liquid hydrocarbons, are among the most important and desirable of all fuels. Unfortunately they are low in anodic reactivity, and their reactions are complex and can lead to many products. They are strong where hydrogen is weak, and weak where hydrogen is strong. The direct hydrocarbon fuel cell is a most difficult research assignment, but its successful accomplishment entails rewards that would outweigh the difficulties. As their name implies, compromise fuels are of reasonable reactivity, cost, availability, energy content, and not too difficult to handle or store. Methyl alcohol and ammonia are prime examples. Hydrazine would be for specialized applications were its price to drop ten-fold or more. The compromise fuels are likely to be the earliest successors to hydrogen in direct fuel batteries; hydrazine qualifies now for special military applications in which fuel cost is unimportant, and the toxicity of hydrazine can be tolerated.

So far we have not mentioned the commonest fossil fuel, coal. At the beginning of the century, scientists and engineers began to wonder whether the dream "electricity direct from coal" could be realized, whereupon the fuel cell, which had been almost dormant since Grove, suddenly became popular. In 1900, the overall efficiency of steam plants was only about 10%. At this efficiency, they would have offered much less serious competition to a fuel-battery centralstation than today, when this efficiency is 4 times as great. Figure 3 shows how far one man, Jacques, progressed in making electricity directly from a carbon much purer than coal. The caption of the figure explains why we need not consider coal seriously in direct fuel cells today.

CAN INERT FUELS, SUCH AS HYDROCARBONS, BE USED TODAY?

Yes, but indirectly, by changing them to substances, mainly hydrogen, more reactive at fuel-cell anodes. Examples of such changes are the reaction of carbonaceous fuels with steam, which is being widely investigated, and the decomposition ("cracking") of ammonia, which will be used to provide hydrogen for a fuel-battery-powered submarine in Sweden. Indirect systems thus combine a chemical plant with a fuel battery, and the combination brings problems not present with the fuel battery alone. Ideally, the chemical process should be

carried out in the anode chamber to facilitate heat and mass transfer. Indirect systems will be of great interim value.

OXYGEN OR AIR?

For applications such as space missions in which the nitrogen of the air cannot be tolerated, oxygen must be used at the fuel-cell cathode.. For terrestrial applications in which the cost of oxygen is prohibitive, or for which it cannot be carried because of weight or volume restrictions, ambient air must be used. But the use of air has important drawbacks that concern the engineer.

Most fuel-cell electrodes are highly porous so as to make their true surface many times the geometric; this is one road to high geometric current density, current density being proportional to true surface area. At high current densities, cathode pores can become filled with nitrogen; this creates a mass-distribution barrier for oxygen and injures cell performance. One remedy is to make the cathodes very thin (10 mils or so thick) and the pores large, but this introduces problems of its own. Especially in a fuel battery, where passages must be narrow to conserve space, forced convection of the air will usually be needed for acceptable current densities (say, 100 amps/sq. ft.). As nitrogen leaves a battery containing an aqueous electrolyte, this gas may carry with it enough water vapor to interfere with cell operation. Particularly at high current densities, the carbon dioxide (about 0.03%) present in the air may give trouble with alkaline electrolytes either by precipitating solids in the electrodes or by reacting with the bulk electrolyte; scrubbing the air to remove carbon dioxide or frequent changes of electrolyte may be necessary. Clearly, "free as air" needs qualifications as regards the fuel battery.

The problems of air operation are important also because various air batteries that are not fuel batteries (e.g., zinc/air batteries) might be attractive for applications (such as vehicular) in which high current densities are needed. One desirable by-product of fuel-cell research are air cathodes that can serve other power sources as well.

HOW DO FUEL BATTERIES DIFFER FROM STORAGE BATTERIES ?

Storage batteries do not use conventional fuels. Storage batteries contain the chemical energy they convert; hence they must be recharged when this energy is depleted. Ideally, the fuel battery can be an invariant converter that delivers energy so long as fuel and oxqgen are supplied.

These two kinds of power sources are complementary more often than they are competitive. Storage batteries are favored for high power over short times (starting an automobile or short space missions); fuel batteries are favored when the load profile calls for moderate power over longer times (space missions longer than several days). The trade-offs that must be made are not usually simple, and they must be bade on the basis of the complete energy system for the load profile in question; in the case of the fuel battery, for example, one must consider energy source plus fuel plus oxygen plus peripheral equipment with proper debit or credit for the reaction products. To handle high peak loads, storage batteries may be used and kept charged by fuel batteries in continuous operation.

Metal/air batteries, such as the zinc/air battery mentioned above, are hybrid devices; as regards the anodes, they are storage batteries; as regards the cathode, they are fuel batteries. A hybrid device of a different kind is the fuelstorage-battery of Figure 4, in which the fuel (methyl alcohol) is stored in the electrolyte (potassium hydroxide) that changes to carbonate as the battery operates; the solution must be replaced when the fuel is exhausted, and the cost of potassium hydroxide, unfortunately not negligible, enhances the energy cost. The cathode operates on air.

WHY DO WE WANT FUEL BATTERIES?

Because they are convenient and promise eventually to be low-cost sources of electrical energy. Cost must be judged relative to convenience: because of theconvenience it offers, a fuel battery may prove successful in an application (e.g.. a space mission) though the cost of the energy it produces is prohibitive by central-station standards.

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