Cellulose processing data

Figure 12. Relation of glucose selling price to delivered cellulose substrate costs for enzymatic hydrolysis process. Data for 250,000 t/yr plant 90% overall process efficiency, 50% enzyme recovery (reuse).

Figure 10.6. Effect of processing method of internally plastieized diethyl cellulose on tensile sbength. 1 -one-step kneading for 20 min., 2 - one-slep kneading for 60 min., 3 - two-step kneading process. [Data from Seung-Hwan Lee Shiraishi, J.AppL Polym. Sci., 81, No.l, 5th July 2001, p.243-50.]...

This work suggests novel materials to enhance the production of bioethanol from pulp and paper industry wastes. The extractant design problem is formulated mathematically to include process data and solvent properties tailored to the use of cellulosic waste substrates. The simulator is interfaced with available molecular design synthesis algorithms to search and select chemicals of desired and/or optimal performance. The materials designed herein can initiate more detailed analyses and laboratory experiments to validate and support the screening results. 

Measurements of particle porosity are a valuable supplement to studies of specific surface area, and such data are particularly useful in the evaluation of materials used in direct compression processes. For example, both micromeritic properties were measured for several different types of cellulosic-type excipients [53]. Surface areas by the B.E.T. method were used to evaluate all types of pore structures, while the method of mercury intrusion porosimetry used could not detect pores smaller than 10 nm. The data permitted a ready differentiation between the intraparticle pore structure of microcrystalline and agglomerated cellulose powders. 

Most often, the rates for feedstock destruction in anaerobic digestion systems are based upon biogas production or reduction of total solids (TS) or volatile solids (VS) added to the system. Available data for analyses conducted on the specific polymers in the anaerobic digester feed are summarized in Table II. The information indicates a rapid rate of hydrolysis for hemicellulose and lipids. The rates and extent of cellulose degradation vary dramatically and are different with respect to the MSW feedstock based on the source and processing of the paper and cardboard products (42). Rates for protein hydrolysis are particularly difficult to accurately determine due the biotransformation of feed protein into microbial biomass, which is representative of protein in the effluent of the anaerobic digestion system. 

Both digester systems exhibit extremely low levels of detectable cellulase activities (exoglucanase, endoglucanase, and -glucosidase) when compared to industrial saccharifying processes (See Table III) in which the hydrolysis of cellulose in the feedstock is optimized with respect to enzyme loading. Therefore, the data indicate the level of improvement that may be made to attain maximum rates for cellulose hydrolysis in the anaerobic reactor system. 

Current data indicate that the analysis of cellulase enzyme activities may be the best method for determining the projected cellulose conversion of the overall system, and therefore the hydrolytic power of the system under evaluation. With development, the analysis of enzyme activities may also serve as a "real time" method of monitoring the stability of the system, with radical changes in enzyme activities indicative of potential process upset. 

The advances made in enzymatic hydrolysis of cellulosic materials (14) are also of interest. This technology involves only moderate temperature processes in simple equipment which promises to be of significantly lower capital cost than the pressure equipment associated with conventional acid wood hydrolysis processes. All of these considerations combined to lead us to study processes for ethanol production from wood, especially in an effort to obtain data for material and energy balances, and possibly for the economics. 

A relationship has been developed by means of which more valid values are obtained by GPC for the average degrees of polymerization for cellulose. This can be extended to other polymers. With automation of data acquisition and computer processing of data, a differential molecular weight distribution and complete information on DP of the sample are available in very short order with a low degree of error. The ready availability of narrow, well characterized polystyrene fractions for calibration makes this procedure highly attractive in view of the lack of similar standards of cellulose. 

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