Paper pulp type effect

Filtration is the most straightforward, probably the oldest form of sugar liquor clarification process. Filtration is effected with plate and frame pressure-filters or some type of leaf pressure-filter such as Sweetland filters with stationary suspended circular leaves covered on both sides with filter cloth. A filter aid of some sort (diatomaceous earth, paper pulp, or kieselghur) is essential to the operation. The precipitated calcium carbonate serves as a filter aid in the carbonation process. The liquor is mixed with the filter aid and forced under pump pressure through the fabric, which retains the cake and allows the clear liquor to flow through. The retained sugar in the cake can be washed out with hot water. Filtration is no longer used as the sole means of clarification. The process is used for further clarification of the liquor from a carbonation or phosphatation process. 

From these results, it may be concluded that the degree of refining has a relatively small effect on the bulk conductivity of paper. A small change in the electrical properties is also observed for different pulp types in paper. These variations are not significant when compared with the variations resulting from a change in relative water content. For cellulose the conductivity increases with water content by a factor of 1014 from 0% to 20% water content 8). 

Investigations of variation in fiber began some years ago. Using polymeric isocyanate treatment, Maldas, Kokta, and Daneault reported the differences in mechanical properties between aspen, spruce, and birch, and between sawdust, cotton fiber, and fiber from paper pulp processing." Typically, aspen and birch provided better properties than softwood spruce. At 30 percent loading, the highest modulus at 1 percent strain was found with two types of treated pulp, followed by cotton fiber, and then treated sawdust. The effects of isocyanate treatment were more dramatic with sawdust. 

The compressors to be covered in this book are those using mechanical motion to effect the compression. These types of compressors are commonly used in the process and gas transport/distribution industries. A partial list of these industries includes chemical, petrochemical, refinery, pulp and paper, and utilities. A few typical applications are air separation, vapor extraction, refrigeration, steam recompression, process and plant air. 

The ZPE and LTF Hazard Assessment Schemes have been successfully used to assess the relationship between laboratory sublethal toxicity data and field measurements of the Canadian pulp and paper Environmental Effects Monitoring Program. Based on these results and the flexibility of the methods, both ZPE and LTF may be used for regulatory monitoring of other types of industrial effluents. 

The effect of burning tires or TDF in waste-wood (hog fuel) boilers in pulp and paper mills was generally unfavorable on the emissions. Particulates increased in every series of tests when the TOF percentage was increased. The reason for this is pr ably due to the type of emissions control devices used on hog fuel boilers venturi scrubbers. The effectiveness of venturi scrubbers decreases as the particle size in the emission decrease. Zinc oxide is used in the manufacture of tires, and is present in significant quantities in scrap tires. Zinc oxide has a relatively low vaporization temperature and is vaporized when tires are burned. When zinc oxide vapors condense, they form sub micro-sized particles that are too small to be removed with a venturi scrubber. This is verified by comparing the zinc emissions in hog-fuel boilers to baseline. Zinc emissions increased in most cases 300 percent (and in one case, almost 50 times the base line emission rate). The effect of burning tires on other pollutants was mixed, and distinctive trends could not be determined. 

Sulphate Liquor.—One ton of sulphate pulp which is used for the manufacture of Kraft paper produces about 2,000 gal. of liquor which is to be concentrated from 10 to 20°B6. Usually a double or triple effect of the horizontal type is used for this purpose, and the capacity is from 2 to 2K gal. per square foot according to the steam pressure. The concentration of this 20°B6, liquor is continued... 

This paper describes some recently completed work on the electrical conductivity of paper. A reliable method of measuring bulk conductivity of paper, where the contact resistance is reduced to negligible values, has been developed. A study of the effect of some papermaking variables, such as the type of pulp, the degree of refining and the fiber orientation, on the bulk conductivity of paper is reported. Finally, an investigation has been made into the current transient phenomena exhibited by paper upon the application of an electric field. These transient currents were interpreted as the transport of ionic species within a water associated fibrous network making up the paper. 

In the study described above, strong evidence was shown that for the case of James River conductive base paper, a pressure of 13.8 Mfa applied to stainless steel electrodes was sufficient to effectively reduce contact resistance to negligibly small proportions. In the study described below the question as to whether the in situ pressure conductivity method would also be appropriate for different types of nonconductive papers which exhibit varied surface morphology is addressed. Consequently, paper samples were prepared, with basis weights of 60, 115, and 190 g/m2, all with a 1 1 ratio by weight of softwood-hardwood pulp, in a centrifugal dynamic vertical sheet former. Each of... 

In Fig. 15, it is seen that the sheet made of cotton linters is more conductive than the other sheets. The sheet made with "Seagull W" hardwood pulp is the least conductive while the three other pulps have intermediate conductivity values. This behaviour seems to be related to the size of the different types of fibers used to make the sheets. As mentioned previously, hardwood fibers are shorter than softwood fibers, and consequently, there are more interfiber contacts in the sheets made of hardwood fiber. The surface area of a contact is very important to the conductivity. There may be a constrictive effect due to smaller surface at these contacts which results in a restricted flow of ions through the paper, and therefore a lower conductivity. Cotton linters are chemically different and longer than wood fibers and the sheet made of these fibers is more conductive. The difference between the three softwood pulps is probably related to a different chemical composition of its fibers. 

The type of pulp in paper also has an effect on paper conductivity. However both effects are negligible when compared to the effect of the relative humidity. Furthermore, chemical additives can completely dominate other paper variables in... 

Cellulase is a complex of enzymes showing various types of activities. Cellulose substrates include highly resistant crystalline forms such as cotton, various types of microcrystalline cellulose such as Avicel and hydrocellulose, sulfite pulps such as Solka Floe, as well as filter paper and cotton fabrics. More susceptible substrates include swollen or reprecipitated cellulose, cellophane, and ball-milled cellulose. Most susceptible are the soluble derivatives (of low D.S.) such as carboxymethylcellulose and cellulose sulfate. It is not surprising that there are many assay methods to detect or measure cellulase (9). These methods differ markedly in sensitivity, and in cellulase components detected, depending on the substrate used, the effect measured, and the duration and conditions of... 

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