Mandate Can Put Producer Gas on Top of the World,
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says "Azote"
Sir Alfred Faulkner Now Has in His Hands the Means for Raising What is Now an. Inferior Fuel to at Least the Efficiency of Petrol THE era of compulsion has arrived; "mandate,' the
• Americans call it. It is well. Without this mandate, producer gas would continue getting nowhere; with it, this poor , relation, this Cinderella of fuels, • may eventually marry her prince and come to live along with other princes, black marketeers and stockbrokers in Park Lane or Kensington.
That Sir Alfred Faulkner, Director of Producer Gas Vehicles, has " man dated " 10,000 road-transport vehicles to don the mantle of pro-. ducer gas, automatically puts into his hands the means for raising the performance of this gas (gaz pauvre, as the French call it, cynically but truthfully) from a figure which may be represented by 63 (13.Th.U. in a cubic foot of explosive mixture) to 100, that of the lordly petrol. Nor is this figure the limit of possible attainment, because octane value, or utili• zation possibilities, are concerned alongside the calorific values quoted above.
Wealth of Data to Direct Development
A fund of information created by the operation of so many vehicles, wisely and unobtrusively collected, cannot fail to provide the director with potential materials which, in the hands of his " back-room boys," can point the way along which to travel in order to attain the desired goal.
There has been much controversy in the producer-gas field in recent months. The Duke of Montrose stirred things up considerably with his criticism of the Government's policy of 10,000 vehicle conversions, and his own proposal of 50,000 as an
alternative: The • Government emergency plant—the " haggis' the B.C.U.R.A. and the plants of the makers already supplying the market, all got mixed up in a somewhat acrimonious ' debate in the House of Lords.
This row apparently produced some acceleration of Government action, as Lord Ridley was appointed Director cif Producer Gas Vehicles. Unfortunately, his Lordship was more urgently required elsewhere in the war-effort organization, and his translation caused a delay of a month or two until his successor .was appointed in the person of Sir Alfred Faulkner.
Sir Alfred's administrative experience has been wide and his record of accomplishment good. His attack on the problem of producer gas suggests that he is taking a broad view of ,the matter, and he is endeavouring to make use of the existing countrywide organization of the motor trade. This organization is underworked in existing 'circumstances, and should be available and adaptable for the purpose of the distribution and maintenance of the plants as they become ready.
Differences in the Two Government Plants
The specifications of the two compulsory slants have now been disclosed, and, whilst possessing points of similarity, they are representative of two basic types in so far as concerns the use of water injection. Interest attaches also to the filtration arrangements, which differ considerably. Actually, the variations in the design of the plants in use in this country are only hi details.
Chief points of possible variations in producers are those of highor low-speed draught, and wet or dry • blast. High-speed draught is the more widely used. One up-draught producer, at one time holding a prominent position, has disappeared. Another has been in production for some time and still is, whilst a third recently arrived from a strong supporter of the cross-draught type. Updraught, low-speed producers seem to have' been developed more satisfactorily for charcoal fuel; Sweden, France, and more recently Australia, have followed this line.
The controversy between dry and wet blast has never been settled in favoiir of one or the other. It is undodbtedly a fact that water (or steam) injected into the fire zone gives a gas richer in _hydrogen than • the dry method. This has been • proved chemically. Tests on the
dynamometer of a certain wet plant run alternately wet and dry, do not show an advantage in actual brake horse-power in favour Of the wet runbig; rather the other way. Unfortunately, in neither of these cases have both the mechanical and chemical tests been in combination. The fact of loss of mechanical power still remains unexplained chemically.
On the other hand. Lhave heard of . a wet-blast plant that would not run at all without water injection.
Generally speaking, it is doubtful if any difference between the two systems can exceed 10 per cent., judging by the difference in value of the two gases. In such circumstances, therefore, it is dearly not possible to go far wrong no matter which system: is used.
Analysis of plants on the market shows a preponderance of dry-gas operation. One of the older plants which was formerly operated wet, was replaced by a model functioning on tie dry-blast principle. Recent' quotations for plants included one make in which it was left to the operator to run either dry or wet at his pleasure.
Wide Variations in
Temperature and R.P.M. It is pointed out that most industrial gas producers are wet operated, but it is important to consider the ' difference between the basic conditions of stationary and portable plants, namely that of constant temperature of the fire in the former as opposed to variations between 2,000 degrees C. (claimed by some makers), and well under 1,000 degrees C., in the case of the latter. This variable temperature is, of course, due to the changing engine speed, which ranges from, say, 1,000 to 3,500 r.p.m., and causes corresponding variations in the rate at which the air is drawn through the fire.
Several different things can happen with a temperature range of such magnitude; at the higher temperatures carbon monoxide is being made, but little hydrogen and less methane. The fusion temperature of ash is well below that attained in the fire, therefore, clinker formation commences to take place.
At the lower temperatures, hydro gen and methane are both released. Against these two constituents, which are in the minority in the gas, carbon-dioxide (non-combustible) is given off instead of the combustible carbon-monoxide. Because this monoxide is the senior active partner of the combined gases, the calorific value at these low temperatures falls heavily. This condition is the cause of the want of gas, following the descent of a long hill, during which the draught is slow, due to the engine running with the throttle practically shut.
Charcoal Plants Used with Coal
Filtration of the gases is a much harder task with mineral fuel than when fuel of vegetable origin, such as wood charcoal, is used. In the early days of gas producers, plants developed to consume charcoal were brought over from France and put straight on to anthracite and coke.
This was the cause of mach dissatisfaction with producer gas as a system, because the charcoal plants were not at all suitable for mineral fuel, and the much greater volume of impurities which were' permitted to pass through the filters, which were designed for charcoal and were totally inadequate for coal or coke, ' effectively damaged many engines, ruining not a few.
It is now general practice to refine the gas generated in the producer in five stages, which have been developed as a result of experience from the two-stage filters originally used with charcoal fuel.
There are various applications of these stages; they consist of some combination of the following operations: cooling, arresting large grit, removal of smaller particles, washing with water, cleansing by means of oil and moisture extraction.
Filtration Methods and Substances,Used
The materials used also vary considerably, including coke, dry or oilmoistened, sisal tow, wood or steel wool, coconut matting, textile bags, horse hair, etc., along with water baths through which the gas is bubbled and/ or surface impinged, and oil baths as well or instead. In some cases the oil bath has a further use, that of supplying a certain amount of oil to the passing gas, to be used as an upper-cylinder lubricant. A last operation of filtration, sometimes included, is to take out any water that may remain in the gas before passing it to the engine.
It would appear that considerable progress has been made in filtration from the early days wlien wear to the extent of 0.010 in. -in 1,000 miles was recorded, to somewhere in the region of that of petrol, generally agreed to be not more than 0.001 in. per 3,000 miles. Claims are made of considerably better results than even this, but if the trouble has been pinned down to a figure that does not -exceed the rate of wear with petrol, a bull has been scored.
I should emphasize the fact that this result has been attained only where arrangements can be made for regular daily and even half-daily attention to be given to the cleaning out of the filters and coolers. Such 'maintenance can be carried out only by a special staff having the opera tions entailed as a sole duty. It definitely cannot be left as a side line to a driver, or as one of the multitudinous duties of a shop labourer. We all know that side lines are done or not done at the will of the sideliner.
Under such conditions it is difficult' to see how the operator of a small number of vehicles can make arrangements to. ensure the carrying out of these duties, without which he cannot successfully run on producer gas. To install a separate staff for the necessary cleaning operations can be an economic possibility only when there are sufficient vehicles in service for the extra cost incurred to be spread over. It is a point that will need careful consideration in the compulsion scheme.
Confine Conversions to Big-enough Fleets
The argument, as set out above, suggests the advisability of Confining the converting of percentages of fleets to those comprising sufficient vehicles to ensure that the number adapted to run on producer gas is large enough to permit The economic operation of such a maintenance • scheme.
Against this there is the fact that, in such circumstances, there would be many owners of few vehicles, none of which would be required to use producer gas. Accordingly, the procedure suggested would penalize the larger operator.
It is to be hoped that in the manu facture of 10,000 plants, the Directot of Producer Gas Vehicles will make use of the members of the Mobile Producer Gas Association, and their resources and accumulated experience.
If, however, he had decided to employ the Association as a whole to allocate to each of its members a sec tion of the plant upon which they could specialize and become experts, with one of them to assemble the manufactured parts, then the economics of production would not appear to be sacrificed, and the Director would have roped in the experience of producer gas that 'these makers cannot fail to have acquired by their activities "of the past few years.
10,000 the Thin End of the Wedge
It is, of course, obvious that 10,000 units will not be the limit of the scheme, but, once started, only the finish of the war can see its conclusion.
The scheme is of sufficient value to enable data to be collected that will prove invaluable for the technical progress that may be envisaged in the progressive development from the initial stage. There is much technical progress to be made. There is little doubt that such research has actually been in full swing in both Russia and Germany for the past -three years or so, and, as usual, these nations are considerably in advance of us.
It was suggested earlier in this article that the design of producer plants is fixed within pretty narrow limits; the plant is made to suit the gas. The obvious line is to study the gas and not the plant. For nearly 150 years producer gas has been " just what comes from coal when we warm it up rather a lot." It is an uncontrolled process.
To De-nitrogenize or to "Fischer Tropsch "
After looking at what controlled chemistry 'is doing in the U.S.A. in the making of 100-octane petrol and synthetic rubber, let us set some of our back-room bop On the job and find out how to take the nitrogen (over 60 per cent.) out of the gas, or. perhaps, " Fischer Tropsch " it, and synthesize the carbon-monoxide and hydrogen to that richest of gases, methane.
There are other possibilities than these. It is in this way that producer gas can, quite conceivably, be brought to real life, when there would be no limitations to its possi bilities. .
It is, perhaps, presumptuous to write of or suggest such possibilities; Sir Alfred Faulkner may already have his technicians on the job.