T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R E'. The yields obtained from sawmill waste are subject to many fluctuations. Where all the timber has been boxed for turpentine before being cut for lumber the slabs are very rich and the yield is uniformly good. There seems to be a regularity in the changing yield, however, probably depending in part on the season a t which the logs are cut, and in part on imperfect condensation in summer. During the winter months a yield of about one and one-half gallons refined product to IOO cu. ft. chips or sawdust is the rule. I n summer, particularly in July and August, it may fall to one-half that amount or less. Since the raw material costs nothing we have to consider only the daily labor and expense charges, and interest, insurance, depreciation and taxes. The daily labor and expense charges usually lie between ten and twenty cents per gallon in a properly constructed plant, depending of course on the yield. The average cost including all charges should lie between twenty and thirty cents per gallon in a sawmill cutting a t least IOO,OOO ft. per day. ,4 plant should hardly be installed in connection with a smaller mill, One other form of utilizing sawmill waste may be mentioned. A plant has been operating in Texas in which shavings from a planing mill were converted into paper pulp, from which a very good grade of brown paper was made. I n the preliminary digestion a small amount of turpentine is recovered. As far as I know mill waste from the long leaf pine is the only kind whose recovery has been attempted commercially in this country. Light W o o d - By far the most important raw material in the pine products industry is the light wood, a name given t o the non-decaying resinous parts of the dead long leaf pine trees. The formation of this material and the general development of the industry have been traced in another place.' 'CVe have to deal here only with the present condition of the plants. This light wood is found wherever long leaf pine grows in the eight southern states mentioned above. The largest quantities and best quality are found in turpentine orchards that have been worked for many years and finally abandoned. If boxed trees have afterward been cut for timber the stumps are very rich down to three or four inches below the level of the ground. Exclusive of short stumps about one or two cords of light wood may usually be obtained per acre. The light wood is usually c u t into four-foot lengths for convenience in handling, but in one plant a t least it was the custom to bring in whole logs 8-16 feet in length and feed them directly into the edging grinder. Hand labor is used exclusively in cutting and preparing the light wood. The wood from stumps is no different from ordinary light wood, excepting that it averages a little richer in turpentine and is more expensive to prepare for the plant. At some plants stumps are sawed off near the ground level, then split by hand. A t others a charge of dynamite was placed in the tap root just below the ground level. This splits the stumps so that very little further labor is required. A third method is to use the stump puller, but in this case the wood must be split by hand and carefully freed from stones and gravel, before i t goes to the edging grinder. Prepared in any of these ways great care must be used in the selection of the light wood going to the 1
J. Soc. Chem. Ind., 26, 811 (1907)
A u ~ .I,909
plant. A cord of light wood may yield anywhere from 6-30 gallons of turpentine. The men who are working with it regularly become very expert in judging its quality, and as the cost of good light wood is not greatly in excess of that for poor wood this skill becomes a valuable asset. For good light wood, yielding an average of 15 gallons turpentine per cord we may consider $2.50 per cord a minimum and S4.jO per cord a maximum price delivered a t the plant. Given good lightwood a t the plant there are three general methods of dealing with it, viz., steam distillation use of a bath, and destructive distillation. These will be considered separately. Steam Distdatzon.-&lore plants of this type than of any other have been constructed during the last five or six years. The simplicity of the process and the large amount of turpentine t h a t could be made in a day were its recommendations. The plants consist essentially of an edging grinder to reduce the light wood to chips, storage bins and retorts like those discussed under the sawmill waste, conveyors to handle fresh and extracted chips, boilers, engines, condensers and refining stills and tanks. The chipped J
