LINCOLN R. THIESMEYER
LINCOLN R. THIESMEYER is President, Pulp and Paper Research Institute of Canada, Montreal.
A paper prepared for the Conference on Pulp and Paper Development in Africa and the Near East, Cairo, 8-20 March 1965. This conference was organized by FAO, the Economic Commission for Africa, and the United Nations Bureau of Technical Assistance Operations
THE PULP AND PAPER Research Institute, of Canada pioneered in studies of the technical feasibility of sending wood in the form of chips in a water slurry over long distances through pipelines from the forests to the mills. This work began in 1957 when very small idealized wood chips were sent through a pipeline loop only 5 centimeters in diameter which had been used for other studies. At first there was not much interest in this subject on the part of the pulp and paper industry. The concept seemed too radical a departure from conventional practices of sending the wood in the form of logs down the river systems or by truck or rail. Moreover, only the chemical pulp mills were interested in having a supply of chips. The large newsprint producers of Canada were still grinding their logs with grindstones to make ground wood, the major constituent of newsprint. However, by 1959 it had been found that an excellent type of groundwood could be produced by putting chips through disk mills, and one newsprint plant after another began to produce some of its groundwood in this manner. It appeared that disk mills, or refiners, would become common and that many mills would be interested in having chips rather than logs as the furnish from the forest to the mill.
Consequently, the institute installed at its new laboratories at Pointe Claire, Quebec, a loop of aluminum pipe 20.3 centimeters in diameter and 0.16 kilometer in length. Conventional chips supplied from a nearby mill were sent through this pipeline at varying velocities and in varying mixtures with the water. The velocities used ranged from 1.2 to 3 meters per second and the mixtures ranged up to 48 percent by volume of wood. At this high concentration of chips a 20-centimeter diameter pipeline would be capable of carrying approximately 800 tons bone-dry of wood per day from forest to mill at a flow rate of 1.8 meters per second, and a pipeline 88 kilometers in length would empty itself in approximately 24 hours. Hence, there would be no strong requirement for a large pile of chips at the mill or at the feeder end of the pipeline. Thus year-round operations would be possible and it was estimated that 900,000 cubic meters of wood would be necessary to feed such a line on a continuous basis the year round. Moreover, it was established that the chip-water slurry could be passed through an ordinary centrifugal pump without damage and, indeed, that the damage to the wood for pulp or papermaking was really negligible after it had been given the equivalent of hundreds of kilometers of transportation in the pipeline.
Publication early in 1960 of a preliminary report on this work stimulated similar experimental studies in the United States and in the Soviet Union. Interest in pipeline transportation of wood chips grew in many countries and is today virtually world-wide. These small pilot-scale studies by the institute stimulated a number of other organizations to make independent studies of the comparative economics of shipping wood by pipeline in certain selected areas of Canada. These showed such favorable results that further studies to determine the parameters necessary for the design of a commercial pipeline appeared to be warranted.
During the summer of 1964 a major pilot-scale installation was established at Marathon, Ontario, alongside one of Canada's pulp mills. Ten companies in the equipment field provided pipe, pump, couplings, mixing devices and other auxiliary materials for the construction of the experimental facilities. Ten other companies provided cash, money to cover out-of-pocket costs and the payment of the research team. These companies included the two major Canadian railroads, a construction and engineering design firm, a pipeline company and six pulp and paper producing companies, five of them in Canada and one in the United States. Thus, the co-operative enterprise made possible a project which would probably have cost close to $1 million had any single company attempted to do it entirely alone. The pipeline company also made available the full-time services of an experienced field engineer for a period of nine months.
At the time of preparing this paper (November 1964) the detailed findings from this project are to remain confidential to the ten sponsoring companies for some indefinite period of time ahead. It is possible, however, to state what was done and to outline the implications for the pulp and paper industry of the successful use of commercial chip pipelines.
The installation at Marathon involved the use of aluminum pipe 15.24 centimeters in diameter, and of steel pipe 20.3 and 25.4 centimeters in diameter. Each was in turn fashioned into a U-shaped stretch of essentially horizontal pipeline 610 meters in length. At the foot of the U, the lines were bent on a 16-meter radius. There were two inclined sections at 10 and 20 degrees to simulate the grades expected in commercial use of such a pipeline. At five locations there were transparent sections made of epoxy resin through which high-speed photography could record flow mixture conditions.
Chips of the conventional type from the regular mill supply were fed from a large pile by means of a snow-blower into a mixing tank by way of a metering conveyor and then sent down through the pump into one end of the pipeline loop. At the opposite end they emerged and piled up on the ground where the water flowed away from them. Large quantities of these chips were subsequently pulped by the kraft process in the mill's batch digesters for comparison with chips that had not received pipeline transportation.
Data on pumping pressures, pump speeds, flow rates, pressure drops, wood-to-water ratios, all related to time, were gathered and recorded by a matched set of instruments and electronic equipment. Every two seconds during the experimental runs a set of 17 readings was taken and sent via wire service for analysis in the institute's computer about 800 miles (1,280 kilometers) away, the results being wired back to Marathon within minutes. Chip moisture and size classification were monitored at the pipeline site. Altogether, approximately 250,000 determinations were made over a period of about five weeks.
From the institute's earlier studies it had not been expected that there would be any significant pipe wear. Nevertheless, this matter was checked with radioactive sections in the two steel lines just to relieve any anxiety which might be felt by potential users of chip pipelines over this point. Small segments of steel were irradiated with Cobal by Atomic Energy of Canada Limited and inserted in the pipeline in such a fashion that they fitted perfectly and did not leave any internal surface irregularity to interfere with flow conditions locally by creating turbulence.
Special study was given to the conditions under which the pipeline would plug and the techniques for removing such a plug when it formed. Periodic sampling of the pH of the water was also a part of the program.
Although it is not possible at this time to give the detailed results flowing from this extensive experimental work, it can be said that it was so successful that many companies in Canada and elsewhere are now talking seriously about installing commercial chip pipelines. It should be admitted, however, that the pipeline is not the answer to all the problems of woodlands operations for the pulp and paper industry. It will only be applied where the combination of circumstances is favorable. In the countries of North Africa and the Near East there would not be the problem of a chip pipeline freezing during the severe winter weather which must be faced in Canada. Moreover, there are many locations where the gradient from the source of the wood or other cellulosic raw material to the mill is such that pumping costs would be substantially lower. (It should be noted here, in passing, that sugarcane cut into lengths of about 5 centimeters was successfully pumped into a sugar mill for a distance of about 1 kilometer on the island of Maui in Hawaii. The line was an aluminum one, 20.3 centimeters in diameter and the sugar cane mixture in water reached approximately 50 percent by volume. The data from the operation of this commercial pipeline for sugarcane corroborated very nicely with the data from the institute's earlier work with its small-scale pilot pipeline in Pointe Claire, Quebec. And it can be said that the experimental work with chip pipelines in the U.S.S.R. has also corroborated the work in Canada.)
Although it is still too early to present quantitative information on the economic impacts of chip pipelines, the following list of potential benefits, each having a dollar value, indicates that the savings in overall costs of the industry should be substantial. It should be emphasized that comparison with other transportation systems must take into account many more things than just the unit costs for the transportation alone.
1. Low unit transportation costs. (May only be true in yearly production of about 900,000 cubic meters of wood.)2. Low labor content of the system. There should therefore be only a minor increase in transportation costs over a 20-year pipeline life.
3. Low annual depreciation charges compared to new rail or road construction. Even a buried line would be less costly than a new road or railroad roadbed.
4. Drastic reduction in mill, forest and in-transit inventories of pulpwood.
5. Suitability to continuous mill operations in ground wood production from disk refiners.
6. All usable wood species transported without sinkage losses. Reduced need for costly selective logging.
7. Utilization of small-diameter wood (tree-tops and branches) which are now largely wasted.
8. Independence from many weather and terrain conditions. This is particularly important in northern latitudes.
9. Elimination of log storage, handling and protection costs at the mill (fire insurance, watering-down of blockpiles, large capital equipment for building blockpiles and processing logs to chips.) No need for log ponds, booms, stackers, conveyors, rafts and tugs, jackladders, woodroom and barkers.
10. Possible re-use of carrier water at the mill for chemical pulping or for papermaking.
11. Availability through the forests of a pressurized water supply for fire-fighting in an emergency. Eventually a permanent system of hydrants at important locations.
12. Possibility of sharing between two or more companies the costs and chip volume use of the pipeline system.
13. Possible multiple use of the line for alternate slugs of chips and other materials (minerals, ores, etc.) also available in the same forest areas. Technology for this exists already.
14. Processing of slash and bark at the head of the trunk pipeline or its subsidiary feeder lines, flumes or conveyors. Hence, removal of the fire hazard represented by present practice of leaving slash scattered over the logged area.
15. Better yields and product quality because of continuous delivery of green wood to the mill.
16. Possible transportation of bark, needles, stumps and roots for utilization at the mills. (U.S.S.R. technicians are already studying this.)
17. Wider choice for the location of new mills, even to urban centers closer to markets.
18. Possible computerized transportation integrated with computerized mill pulping and papermaking.
19. Much faster wood delivery to the mills for much faster processing there on a continuous flow basis.
20. Possible telescoping of mill processing steps back into the pipeline for in-line mechanical and/or chemical treatment. The pipeline, expanded into interconnected tanks and towers, may ultimately feed washed and bleached pulp continuously into the stock chests of the paper machine.
Thus, the proliferation of hydraulic wood chip pipelines will have far-reaching consequences to the pulp and paper industry. They will be nothing short of revolutionary in changing the industry's whole aspect, from highly-mechanized operations in the forest to streamlined, simplified and continuous processing equipment at the mills. Such a revolution is essential if the industry is to continue to grow and prosper in the increasing competition with its more sophisticated competitors who axe now offering an amazing and disturbing array of cheap films, foils and plastic substitutes for paper and paperboard.
Carrying liquids over long distances in open flumes is an ancient practice. Closed pipelines for liquids and then gases have become commonplace with the advance of industrial technology. In this century we have seen the advent of solids transportation in pipelines over ever-increasing distances in North America - in the mining industry, the coal industry and the petroleum industry with its Gilsonite pipeline in Utah. Hydraulic pipelining of solids is off to a good start; but this practice is still in its infancy. And as yet there is little technical literature on the subject.
Today we are shooting encapsulated men and equipment into orbit in the ocean of air and the thin gases of our upper atmosphere. It is therefore logical that shipment of other encapsulated solids in other fluid media in pipelines on the earth's surface or just beneath it should be studied. -The Alberta Research Council in Canada has sent capsules containing small-particle solids in a petroleum line for some 90 kilometers. Now they propose that wheat be put into 1-bushel (35-liter) plastic capsules and sent in petroleum pipelines to Montreal, the plastic being reconstituted after the trip for use so that everything which has been carried in the line would be sold.
Canada, which has a land area greater than the United States, only sparsely settled and lacking the intricate road and railroad systems of that country, and with great distances from the raw materials to the centers of manufacturing, is "a natural" for development of a network of pipelines. Such a network is already being established to send the energy of its fabulous prairie resources of oil and gas to its own major industrial centers and to the even greater markets of the United States. So much of the land is owned by the governments of the provinces that problems of rights-of-way for pipelines are minor. Moreover, the two Canadian railroads are partners with the pulp and paper industry in studies of pipeline technology, rather than bitter opponents. This comes from enlightened self-interest, because, in many situations in Canada the most sensible routes for the lines would be along the already-cleared, graded, protected and easily-accessible rights-of-way of the railroads. And, when it has been demonstrated that hydraulic pipeline transport of wood in water is much cheaper than the lowest freight rates which could be set without running at a loss (as the author believes it surely will be), the railroad companies could own and operate the pipelines on long-term service contracts to their customers. In many cases, although a pipeline can cut across country so rugged that it would be too costly for a railroad to cross except close to the grades of circuitous river beds, nevertheless the longer way round may prove to be the faster and the cheaper way for transport when all the costs are analyzed carefully.
Canada's pulp and paper industry, the largest manufacturing enterprise in the country and therefore a major factor in the economy because of large exports, should certainly consider pipelining its raw material wood - from the forest to the mill. And it has been doing so. For generations the industry has largely been dependent on the colorful driving of logs down the abundant river systems, sometimes for as for as 600 to 900 kilometers. More recently, trucks and flatcars or boxcars or barges have each year carried part of the several million tons of pulpwood to the mills, mostly in the form of logs which have been handled and re-handled many times before they have ended up in huge blockpiles at the mills. Today, the river drive has become more complicated and costly, because construction of power dams has created lakes so that logs have had to be gathered into rafts and towed along the lakes down to sluices round the dams.
In this way, at least 5 percent of the wood has sunk to the bottom of the rivers, and salvage has been only nominal. To an industry which operates on profit margins of less than 10 percent this represents an appreciable loss, one that has been accepted up to now as an inevitable cost of being in the business.
Hardwoods like birch and maple and oak get saturated and sink easily. Therefore, if there is a mixed stand of these hardwoods plus the preferred softwoods (spruce, fir, pine) at a remote location and one must bring the wood by river drive to the mill, there is need to do a selective logging job, picking out the softwoods only and leaving the hardwood to reach overmaturity and rot away. This is much more expensive than clearcutting the whole area, leaving a few seed trees to bring back the next crop, and sending almost all the trees down the transportation system to the mill. And such selective logging and poor utilization is less than comforting to wood conservationists.
The Canadian industry is far too dependent upon a rigorous climate. In winter the river transportation systems are frozen. A big inventory of logs must therefore be built up in the forest, awaiting the spring freshets. Thus, with millions of tons of wood tied up in piles in the woods, more millions tied up in log blockpiles for operations during the long winter months at the mills and an unknown number of tons lost to the stream bottoms, the industry now has a great deal of its money tied [] unproductive inventory.
In river driving, the wood is subjected to many cycles of alternate wetting and drying from the time it is cut until it finds its way into the pulpmill. In some cases, the interval from cutting to processing is as much as two years. During part of this time it is vulnerable, like any dead organic material, to attack by bacteria, fungus and insects. It is not surprising, therefore, that scientists find better yields and superior strength qualities in pulps and papers made from green, freshly-cut wood than in those made from alternately wetted and dried, or aged wood.
For many years now, chemical pulps have been made by producing chips from logs and steeping them under pressure in aqueous acid, neutral or alkaline solutions in big vessels in order to dissolve and flush away the lignin in the wood and free the cellulose fiber for papermaking. These chips are about 1.5 x 1.2 x 0.6 centimeters in dimension. In some cases they have been loaded into and unloaded pneumatically from barges, shipholds or boxcars and blown with air into storage bins or piles. The maximum practical distance for such pneumatic transport has been something less than two kilometers. Beyond that the power costs become too great. Moreover, in such transport at high velocity and without a protective liquid film around each one, the chips bang into one another and into the pipe walls to produce attrition of the wood. This action is deleterious to subsequent pulping and papermaking. So long-distance pipeline transport of chips in air or gas is unthinkable from both the technical and economic standpoints.
These then are some of the reasons why it was particularly appropriate for Canada to pioneer the study of the transportation of wood chips in pipelines. But surely there are many other parts of the world where such transportation would also be advantageous, including countries in Africa and the Near East. In districts which are semi-arid, it could be that the pipeline would serve the dual purpose of bringing a water supply as well as a supply of cellulosic raw material to the mills. In areas where the terrain is relatively flat, there would not need to be very high pressures for pumping through pipelines of relatively short lengths; they could be laid on the surface with only a minor cost for anchoring. It will be a source of pride to Canadian researchers if the technology which they have pioneered in the matter of chip pipelines can be adopted and used with benefit by the developing countries of these regions.
BREBNER, ARTHUR. 1964. On the pumping of wood-chips through a four-inch aluminium pipe-line. Can. Jnl Chem. Eng. Vol. 42, No. 3, June 1964, p. 139-142.
ELLIOTT, D. R. Transportation of pulpwood chips in pipe lines. 1960. Pulp Paper Mag. Can. Vol. 61, No. 5, May 1960, p. 170-175, 2 tables, 2 figs., app.
ELLIOTT, D. R. and DE MONTMORENCY, W. H. 1963. The transportation of pulpwood chips in pipelines. Wood lands Research Index, Pulp Paper Res. Inst. Can. No. 144, August 1963, p. 69, 19 figs., 18 tables, 6 refs.
ELLIOTT, D. R. 1964. Woodlands mechanization, chip pipelines and research. Woodlands Research Index, Pulp Paper Res. Inst. Can. No. 151, June 1964, 12 p., 2 app., 4 refs.
KOROLEFF, A. 1964. Translations of two recent Russian articles on the water transportation of wood chips in pipelines.
A. Transport of wood chips by water in pipeline GULISASHVILI, B. G. and NODARAYA, V. L. Lesn. Prom. (Forest Industry) No. 12, December 1963, p. 9-10.B. Hydro-transport of wood chips in pipelines KOROBOV, V. V. Bumn. Prom. (Paper Industry) No. 1, Jan. 1964, p. 13 - 15.
Woodlands Research Index, Pulp Paper Res. Inst. Can. No. 150 (Translation Series No. 52) May 1964, p. A-1 to A-5 and B-1 to B-51 4 figs., 2 tables.
THIESMEYER, L. R. 1963. Testing the pipeline concept. Pulp Paper Mag. Can., Vol. 64, No. 2, Feb. 1963, p. WR-50-52.
Companies providing funds to the chip pipeline study:
Canadian National Railways, Montreal, QuebecCanadian Pacific Railway Company, Montreal, Quebec
Champion Papers Inc., Hamilton, Ohio, U.S.A.
Dominion Tar and Chemical Company Limited, Montreal
Foundation of Canada Engineering Corporation Limited, Montreal, Quebec
Fraser Companies Limited, Edmundston, New Brunswick
Irving Pulp and Paper Limited, Saint John, New Brunswick
Marathon Corporation of Canada Limited, Marathon, Ontario
The Ontario Paper Company, Limited, Thorold, Ontario
Pembina Pipe Line Limited, Calgary, Alberta.
Companies providing equipment on loan:
Aluminium Company of Canada Limited, Montreal, QuebecCanadian Ingersoll-Rand Limited, Montreal, Quebec
Greey Mixing Equipment Limited, Montreal, Quebec
Pacific Coast Pipe Co. Limited, Vancouver, British Columbia
Page Hersey Tubes Limited, Toronto, Ontario
Rader Pneumatics (Eastern) Limited, Montreal, Quebec
Sicard Inc., Montreal, Quebec
Tube Turns of Canada Limited, Ridgetown, Ontario
Victaulic Company of Canada Limited, Weston, Ontario
"There must be an easier way than, this of producing wood." (Reproduced by permission of Punch)
