INDUSTRIAL AXD ENGIA'EERING CHE-ZIISTRY
August, 1928
the higher the amount of oxygen carried in the stock by the black the more rapid the deterioration, although this deterioration was only approximately a direct function of the amount of oxygen present. Table IV-Relation between Oxygen Content of Mixtures of G and M Blacks on Properties of Rubber Compounds (100-minute cure a t 140" C )
G
BLACK M
ELONGATION
70 K g . p e r s g cm.
q0
0 25 50 75 100
Table V-Effect AT
140' C.
Minufes
70 5 4 3 2 1
298 288 269 269 248
2 2 2 2 2
20 25 33 59 66
50070 ELONGATION
AT
BREAK
TENSILE, AGED6 DAYSAT 70' C.
K g . p e r sq. cm. K g . p e r sq. cm. 169 191 220 223 219 113 113
R
ORIGINAL
of Various Blacks on Time of Cure MODULUSAT TENSILE % OF ORIGINAL
TIMEO F CURE BLACK
OF
ON AT70'C. BLACK (Best Cure)
AT
BREAK
Kg p e r s q cm.
165 183 198 222 232
100 75 50 25 0
9;
data agree very well with those presented previously. The figures for the ink black are omitted, since it was too much under-cured to give satisfactory results. The more rapid deterioration of these stocks compared with those shown in Table I1 is due to the fact that diphenylguanidine does not have so great an antioxidant action as Grasselerator 808. Conclusion
TENSILE, TENSILE OXYGENAGED4 DAYS
MODULUS AT 500 '7,
~~
288 304 274 273 250 201 225
9 10 26 26 45 8 35
Another series of tests was made using the same amount of accelerator and changing the time of vulcanization to give the maximum physical properties. The compounds used for this test contained 100 parts of pale crepe, 5 zinc oxide, 4 sulfur, 1 stearic acid, 25 of black, and 0.75 diphenylguanidine. These results (Table V) again show the very great difference in the rate of vulcanization of compounds containing the same amount of black but different amounts of oxygen and also show the difference in the maximum physical properties produced under these conditions. It will be seen that the
819
The data presented herein show that in general the presence of oxygen on carbon black retards the rate of vulcanization in direct proportion to the amount of oxygen present and also decreases the maximum physical properties obtainable with a given amount of accelerator. The aging data shorn that the presence of this oxygen on the black increases the rate of aging as the amount of oxygen increases, but not in direct proportion to the per cent of this oxygen present. I t can be concluded, therefore, that compounds which contain a small amount of oxygen, such as thermatomic, G black, or acetylene black, will give better aging stocks than compounds containing higher amounts of oxygen such as lampblack and standard channel blacks. Yo correlation could be found between the acetone extract, iodine adsorption, or oil adsorption, and the effect of these blacks on the rate of cure or aging. Acknowledgment
The authors wish to express their appreciation to the Combustion Utilities Corporation for peTmission to publish these results and to C. J. Wright, chief technologist of this company, whose interest and support have made it possible to carry on this work. The cooperation of Ira Williams, of the Grasselli Chemical Company, is also gratefully acknowledged.
Paper Pulp from Logging Waste in the Douglas Fir Region' Allen H. Hodgson2 OFFICE O F FORESTPRODUCTS.
u. s. FOREST SERVICE, PORTLAND, ORE.
HE Douglaq fir region is located west of the Cascade
T
Range in Oregon, Washington, and British Columbia, but this discussion is confined to Oregon and Washington. Within this region are found some of the heaviest stands of timber known to man. This timber represents 25 per cent of all the remaining softwood saw timber in the United States. It is being cut a t the rate of over 12 billion feet board measure per year. The timber is composed for the most part of yery large trees, many of which are 6 to 10 feet in diameter and 280 to 300 feet high. Small trees, 10 to 20 inches in diameter, are usually found under the large ones. The large timber is usually Douglas fir, western red cedar, and Sitka spruce. The small trees most frequently found are western hemlock and white fir, both species in little demand for lumber but having high values for paper pulp. Most of the remaining timber within the region is situated in rough, mountainous country. The combination of very large logs and very rough country has forced the logger to develop and use the largest and most powerful logging machinery in the world. To make this huge equipment, which is costly to purchase and to operate, 1 Presented at the Pacific Xorthwest Regional Meeting of the American Chemlcdl Society, Reed College, Portland, Ore , April 7 , 1928 2 Associate Forester, U S Forest S e n i c e
an asset rather than a liability, quantity production is the all-important factor. Small logs cannot be economically handled by the large logging units, and for this reason the undersized trees, together with broken and defective logs from the larger ones, are left in the woods in the form of slash, to rot or to be burned. In extreme cases the volume of timber taken from the forest as merchantable logs amounts to only 25 per cent of the original stand. Furthermore. as the lumber cut in Oregon and Washington increases during the next few years, the amount of waste wood available in connection with the lumber industry will become proportionately greater. More and more as the operations go back into the higher mountains, they will encounter stands of timber with higher percentages of pulpwood species and lower percentages of the Douglas fir, which is now being sought. If a big demand for pulpwood is built up, this might for some time offset largely, or altogether, a gradual falling off in the production of logs in Oregon and Washington, the beginning of which may be less than a decade ahead. There is no reason, other than lack of pulpwood markets, why there should not be operations in Oregon and Rashington designed primarily to secure pulpwood, or why operations in stands containing a large percentage of pulp species
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I Y D C S T R I S L A J D ELVGlNEERIh7GCHEMISTRY
Vol. 20, No. 8
shonld not he designed to secure saw timber from the material most suitable for that purpose and pulpwood from the remainder of .the stand. There are great possibilities in the integration of the lumber and pulp indusiries, which would make entirely feasible hrge use of both logging and sawmill wast.e pulp. A good start toward such a combination, both a.t the mills and in the woods, has already heen made. The use of waste wood from mills has temporarily taken the lead because of the ease with which it can be secured. As time goes on, however, the nse of woods waste for pulp will come into its own since these supplies are coniposed of a better grade of material.
are delivered by rail. The trimmings, dumped into a trough, are conveyed by machinery to a huge bunker. They are then moved by gravity to the wood room, where they are converted into chips. Black knots, hark, and other defective material is sort,ed out and sold as fuel. Thus every piece of wood, no matter how small, is utilized. Mill wast,e is delivered to the pulp plant8 in various forms, such as slabs, sawmill and box-factory trimmings and edgings, for which a fair price is received. I n some cases the waste wood is converted into pulp chips at the sawmills, with equip ment installed and owned by the pulp manufacturers, and is delivered in this form t u the pulp plant.
Utilization of Mill Waste
System Developed by One Company
I n years past only a negligible amount of mill vraste was used hy the pulp and paper indu-try. The raw material was taken in the fomr of saw logs. vliich \rere also suitable for
As suggested above, it is predicted that the pulp mills will soon iurn more and more to that great supply of raw material which is now left by the loggers in the woods. Already some paper-pulp mills are looking to this source of supply and becoming more interested in machinery by means of which it can be profit:ibly salvaged. The problem contains many involved economic and mechanical factors, hut these can be overcome, as has already been demonstrated by a t least one company within t,he region. The Cron,n-rSillamette Paper Company has been interested for a number of years in the proposition of saving woods waste. It bas finally worked out a highly efficient system of relogging. which follows after the heavy machinery operation. The small logs and chunks are logged by means of newly developed, light,, mobile, gasoline-driven machinery which is inexpensive to pnrehase and to operate. With this equipment, about 10,000 board feet of small lo@ per acre, or about 15 per cent of the original stand, were salvaged and shipped b>; rail and water a distance of over 100 miles to the pulp mill near Oregon Cit,y. It is understood that the material was handled a t a profit and that the operation passed out of the experimental stage. Iluring four months in the summer of 1926, the company saved by its relogging operation more than 4 million board feet of wood that would have otherwise been wasted. Results of Forest Service Survey
rlholos oy ,,UlhO.
Woods Losses i n the Douelas Fir Resion A y r u i i y accumulation of 4 . 1 hjiliun board ieet of such materiel i s left io rot or bum b y the iosgers or the Doustar fir region
liimber. To\%-, nearly all of the pulp plant,s of these states ore wing some inill waste; in 1926, 18 per cent of the pnlpwiod used in the state of TTashington where the production of pulp has been the greatest. was in the form of mill waste; almost without, exception, nev pulp plants have been located \\-it11reference to the utilieation of mill waste. In a few cases the lumber mill and pulp and paper mills are integral parts of the same plant and practically complete integration is attained. This is the nniversal rule in Sneden and Finland, the important pulp and paper producing counbies of Enrope. At sercrd pnlp mills in TTashington, sanmill waste, which ir piirehasodl const,itntes the total supply of pulpwood. The one at. Bellingham. for example: depends upon waste hemlock and spruce box trimmings. This plant is located betlveen aiid near two sawmills operating box factories. The waste from the two factories is hauled to the pulp plant by anto trucks. Box trimmings from a third factory, 22 miles distant,
Recognizing the importance of the so-called wood waste problem, also the difficulties of even its approximate solution, the Forest Service, during the past two years, has been conducting a general surrey of vood w&e in t,he logging camps of the Douglas fir region. The field work is completed and the results are a t present being tabulated in preparation for the final report. This field investigation covers the logging operations of twenty-four widely distributed, representative companies, and is based on accurate measurements of material found on one hundred and fifty sampleacre plots. The data represent a good cross section of existing conditions. The results of t,he s h d y show that approximately 20 per cent of the timber is being left in the woods in the form of sound materia!, measured down to cordwood size. In addition there is perhaps 5 or 10 per cent of wood in the form of broken pieces and tops too small for any present commercial use. Upon t,he basis of 20 per cent of a stand of 100,000 feet hoard measure per acre, the approximate volume found on the average sample plot, 20,000 feet hoard measure per acre is left in the woods. The loggers of western Oregon and Washington in 1926 cut over about. 145,000 acres of timber land. Upon thcse premises about 2.9 billion fcot board measure or 5,800,000 cords of sound m a t e d , cordwood size and larger, was left in the woods as waste that year. The tremendous quantity of this material left each year to rot or to be burned can perhaps he appreciat,ed when we consider that in 1926 the total pulpwood produced in the United States wm 4,394,766 cords, only 75 per cent in vol-
August, 1928
INDCSTRIAL A X D ENGINEERISG CHEMISTRY
ume as compared with the woods waste in the Douglas fir region of Oregon and Washington. An analysis of the woods waste shows that nearly 40 per cent (1,121,000,000 feet board measure) is in the form of logs, which under present or slight!y improved economic conditions the industry could reasonably be expected to remove from the woods for use as lumber. About one-half of these logs are western hemlock, white fir, and Sitka spruce, while the other half are Douglas fir, cedar, and pine. The remainder of the material (about 60 per cent) left in the woods is in the form of smaller logs, culled logs, and tops. About one-third of this is made up of hemlock, white fir, and Sitka spruce, while two-thirds is represented by Douglas fir, cedar, and pine. Summing up, we find that of the yearly accumulation of 5,800,000 cords of woods waste, 2,320,000 cords are western hemlock, white firs, and Sitka spruce, woods in demand for sulfite and mechanical pulp, and 3,480,000 cords are Douglas fir, cedar, and pine, woods best suited for lumber and having inferior pulping properties even by the sulfate or soda processes, but which are being made into pulp to some extent by these processes.
831
Conclusion
In conclusion it may be stated that FFhen the combined quantities of sawmill waste and logging waste are considered, the raw material in these forms for the paper-pulp industry of Oregon and Washington at present and for a number of years to come is practically without limit. There are three ways by which the life of the lumbering and wood-using industries, including the production of paper pulp, of Oregon and Washington can be extended: (1) reviced tax l a w which will encourage the protection and gron-th of young foreqts; (2) prevention of foreqt fires in virgin and second-growth forests as well as on cut-over lands; (3) better and clo-er utilization of the Jyood which the lands are producing. If the pulp industry continues to develop practical niennc, for making greater use of the sawmill and logging waqte, i t will bc doing a great deal toward helping itself as n e11 as asslating to establish continuous prosperity in the stateb of @reeon and Kaqhington, where the forests give employinelit t o -( me 168,000 local men and pay nearly 6S per cent of the elitire indu.tria1 payroll.
Dew Points of Air-Gasoline Mixtures from Distillation Curves1" Oscar C. Bridgeman BUREAVOF STANDARDS,iX-ASHINGTON,
D . C.
Gasoline was vaporized by a dynamic method in the rium distillation at 1 atmospresence of known amounts of air at temperatures erties of liquid fuel:, phere pressure in the abbence permitting successive approach to complete vaporizaof air. The h a t c h e d a r e a which d e t e r m i n e s tion. For each mixture and gasoline, the temperatheir suitability for use in covers the field of interest in ture-percentage evaporated curve extrapolated to automotive engines, is volaconnection with automotire 100 per cent gave the dew-point temperature. These tility. The accepted laboraengines-namely, air-v a p o r equilibrium distillation values agreed well with values tory test for volatility is the mixtures from 8:l to 20:l. obtained by the method of Stevenson and Babor and A. S. T. M. distillation, a nonThe abscissa of 0 per cent with the results of these investigators. The dewe q u i l i b r i u m process cone l - a p o r at ed represents the point temperatures a t 1 atmosphere pressure, of true yapor-pressure line, for ducted under definitely specigasoline vapor, and of mixtures from 1 : l to 30:l were fied conditions at atmospheric along it the composition of the found to be simply related to the 90 per cent A. S. T. M. pressure. The difficulty of 1i q u i d remains unchanged. points, corrected for loss, and to each other. interpreting the results of this At the other extreme the abtest i n terms of engine perscissa of 100 per cent evapoformance and the lack of a suitable method for estimating rated is the dev-point line and along it the composition of the volatility more directly in such terms led to the inauguration vapor remains unchanged. LTntil recently the study of volaof an extensive study of volatility which has been in progress tility at bhe Bureau of Standards has been confined almost' exduring the past few years at the Bureau of Standards in clusively to the automotive range. This study has included cooperation with the petroleum and automotive industries. the design of an apparatus by Sligh3for determining yolatility From the industrial standpoint the problem of the rolatil- under conditions simulating t'hose existent in the engine maniity of gasoline can be depicted simply in the manner shown fold, the relation between data obtained with this apparatus in Figure 1. The upper solid line is the corrected A. S. T. M. and the ease of engine ~ t a r t i n g and , ~ recently a correlation curve of the fuel, which does not cut either the lines of 0 between volatility data by this method and the A. S. T. AI. or 100 per cent evaporated. The gap at the lower end is due distillation curves of the fuek5a6 The present' study is conto loss of the very volatile constituents at the beginning of cerned mainly wit'h dew points as obtained with the Sligh the distillation, for which correction is made in all of this apparatus and corroborated by experiments with an apparatus volatility work, while at the upper end of the curve the residue analogous to that employed by Stevenson and Babor.' An remaining in the flask a t the end of the distillation prevents investigation of the vapor pressure of gasoline is now in progthe evaluation of the temperature of complete vaporization. ress. The upper dotted line represents the probable curve for equilib* J . SOC.Aufomoliue Eng., 18, 393: 19, 151 (1926).
NE of the basic prop-
0
1 Presented before t h e Division of Petroleum Chemistry a t the 75th hfeeting of the American Chemical Society, S t . Louis, Mo., April 16 t o 19, 1928. 2 Publication approved b y the Director of the National Bureau of Standards.
Cragoe and Eisinger, Ibid., 20, 353 (1927).
* Bridgeman and Cragoe, A m . Pefroleum Inst. Bull., January 31, 1928, p . 54. 6
7
Bridgeman, J . Soc. Autonofive Eng., 22, 437 (1928). IND. ENG.CHBM.,19, 1361 (1927).
