Pulp and Paper 



3141 



CMC from whole tree chips of southern hardwoods which eliminates the inter- 

 mediate drying step. By his process, whole-tree hardwood chips are fiberized in 

 a disk refiner; a caustic reagent is applied as a mist sprayed into the disk refiner at 

 a point approximately half the distance between the center of the disk and the 

 outside periphery. The etherifying reagent is introduced separately by spraying it 

 into the refiner between the point the caustic was introduced and the disk 

 periphery. Both reagents contact the wood while it is being fiberized and while it 

 is in a fluid state. Durso (1981) found that once the etherifying reaction is 

 initiated, the fiberized wood material can be conveyed to any suitable vessel 

 until the reaction is completed. Reaction time is temperature dependent, ranging 

 from about 100 to 5 minutes with reaction temperatures from 55 to 95°C, 

 respectively. 



After the reaction, the ether derivative can be dissolved from the unreactive 

 wood components and recovered by precipitation with alcohol, if a pure deriva- 

 tive is desired. For a technical-grade derivative, one typically containing salt, 

 the entire reaction mass may be dried and ground to suitable particle size. 



25-9 PULPING OF WHOLE-TREE HARDWOOD CHIPS 



Forest managers in the southern pine region need economic commodity uses 

 for the pine-site hardwoods to facilitate intensive silviculture and thereby in- 

 crease yield from their lands. Moreover, they need markets that will accept the 

 mixture of species and diameter classes that naturally occur. Fiberboards (Chap- 

 ter 23), structural flakeboards (Chapter 24), and energy wood (Chapter 26) are 

 commodities that can provide these needed markets. Pulp and paper products, 

 however, probably have most promise. 



For any particular species mix, a pulping procedure can probably be de- 

 vised; one of the most difficult problems facing a potential user of southern 

 hardwoods, however, is maintenance of a stable mix of species. Eschner (1977) 

 identified the biggest problem in the paper industry as follows: "How can the 

 mill get uniform stock to the wet end of the machines?" 



Most of the economic systems for harvesting cull pine-site hardwoods call for 

 chipping trees entire, to yield whole-tree chips with bark in place (figs. 16-18, 

 16-45, and 16-49 through 16-56). In summer, these whole-tree chips cannot be 

 stored for any appreciable length of time. If stored even for a short time in the 

 chip van, the chips start to blacken. For this reason, mills should unload whole- 

 tree chips on arrival for direct delivery to the mill. Removal of fines during field 

 chipping slows chip deterioration while in storage. 



The progress of weight loss in piles of whole-tree chips is similar to that in 

 piles of bark-free wood chips, except that in piles of whole-tree chips incorporat- 

 ing leaves and bark, deterioration is more rapid and problems with heat buildup 

 are more severe. Moran'^ reported that the decay rate for mixed hardwood 



'^Moran, J. S. 1975. Kraft mill experience with whole-tree chips. Presentation at TAPPI Annual 

 Meeting, New York, Feb. 



