Utilization recovered paper

Typically, recycled paper sludge is made up of approximately 50% cellulose, 10 % hemicellulose and 40 % other materials, and has a moisture content of about 60%. For example, with a dry ton of recovered paper for repulping, there is about 0.15 to 0.2 ton of dry short fibers generated. The wet weight of RPS will be up to 0.5 ton including water, short fiber and other solids known as fillers. Because of its high fiber content, RPS is the type of material that can be effectively utilized and converted into ethanol. The ideal method of producing ethanol from RPS is to use the simultaneous saccharification and fermentation (SSF) process. 

Fig. 2.1 Global development of recovered paper utilization and paper production (1961-2002) [1-5].

Recovered paper utilization rate, in percent, is the amount of recovered paper used as raw material in the paper industry, in tons, divided by paper production, in tons, on an annual basis, multiplied by 100. 

Fig. 2.3 Utilization rates of recovered paper of the 12 largest papermaking countries in the world (2002) [1],...

Fig. 2.4 Recovered paper utilization rate and paper production in Asia, the CEPI countries and North America (2002) [1].

Figure 2.4 shows the utihzation rate for the three largest paper production regions in the world where the paper industry uses 85% of the global recovered paper volume Asia, Europe and North America. Paper production in these three regions is between 90 and 100 million tons each, resulting in recovered paper utilization rates of roughly 57% in Asia, 47% in Europe and 38% in North America. 

Fig. 2.5 Recovered paper utilization by paper grades in the CEPI countries (2002) [6].

Fig. 2.6 Recovered paper utilization and collection rates vs. utilization rate in CEPI countries (2002) [1].

Fig. 10.11 Utilization and disposal of solid wastes of recovered paper processing [11].

In addition to the development of new products with previously unavailable property combinations, the task of making the process more efficient is important, particularly in this day and age. The cost factor energy can still be reduced if, for example, the heat of polymerization can be better utilized. It has been suggested that heat pumps be used for this purpose and the energy recovered be employed for the devolatilization step (38). In the same paper the author also suggests the integration in one factory of the monomer/polymer and end product fabrication, the latter since the polymer is already available in the molten state. 

In 1977, Christe announced " his discovery that 02 SbF6 forms stable solutions in aHF, but early work in our laboratories had indicated that 02 AsF6" (which is easier to prepare than the antimony salt °) was not stable in aHF, Later, however, Shen in this group demonstrated that 02AsFfi could be recovered nearly quantitatively from room-temperature solutions in either anhydrous hydrogen flucnide (aHF) or bromine pentafluoride. This indicated that these solvents could be utilized for the liberation of the O2F and as a vehicle for its chemistry. Because it is low melting (—83.6 C) and is an excellent ionizing solvent, aHF has been the preferred solvent for the work on which this paper is based. 

Nanohltration membranes allow partial permeation of monovalent salts such as sodium chloride, while they completely reject bivalent salts and hardness from aqueous solutions. This has led to the use of NF membranes as water softeners by removal of total hardness and sulfates from seawater and for removal of NaCl from cheese whey. NF membranes have also been successfully utilized for treating textile dye and olive processing wastewaters to recover recyclable water. Another common application is removal of color from effluents and process solutions. One such example is the separation of color causing compounds such as lignin sulfonates from paper pulping wastewater. 

Normally, after being heated, these streams are used in the boiler area (deaerator feedwater, cold return condensate, boiler feedwater, RO feedwater) or in the combustion chamber (air preheat). However, economizers can be used to recover and supply heat elsewhere, such as hot process water or hot utility water, especially as used in the food processing and pulp/paper industries. Additionally, recovered flue gas waste heat can be used indirectly i.e., remote process streams can be heated locally with hot steam condensate, and then the cooled return steam condensate can be reheated in the flue gas economizer. An... 

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