Toshiharu Miki

Reaction model of cellulose decomposition in near-critical water and fermentation of products

Abstract The properties of the products obtained in the cellulose decomposition process conducted in near-critical water were analyzed using HPLC, GPC and IR. The properties of the products changed with the progress of the reaction and a reaction model consisting of the formation process of water solubles (WS) and the subsequent second decomposition process was proposed. The WS formation process is a saccharification process where hydrolysis preferentially progresses. The second decomposition process is a carbonization process of WS, where the elimination of functional groups leads to the formation of gaseous products and insolubilization of WS. The hydrolyzate solution obtained in the sacharification process could be used as a feedstock of ethanol fermentation and the fermentation rate of the solution was improved by removing furfurals with an active carbon treatment.

Initial Stage Liquefaction of Coal in the Process of Rising Temperature. (II). Effects of Coal Ranks.

The initial stage liquefaction of six coals, Estevan, Wabamun, Taiheiyo, Wandoan, Illinois No.6 and Lingan coals, was studied. Heat-treatment of coal and a hydrogenated anthracene oil slurry (1: 3 by weight) was carried out using a pipe reactor which was designed to recover six heat-treated samples at progressively higher temperatures. About 3.4min. were required to raise the temperature from room temperature to around 450°C.Pyridine insolubles, PI, decreased with an increase in temperature in all coals studied. In the cases of Taiheiyo and Illinois No.6 coals, PI values of the sixth samples (445°C) were less than 10%, showing that the initial stage liquefaction reaction of both coals was almost completed. The sixth samples of Wandoan and Lingan coals had small PI values of less than 16%. Estevan and Wabamun coals had PI values of around 45% in the sixth samples.In the cases of Taiheiyo, Wandoan, Illinois No.6 and Lingan coals, the change of viscosity of each slurry with temperature showed a maximum. This maximum is caused by the swelling and disintegration of coal particles with increasing temperature. Estevan and Wabamun coals, which did not have small PI values in the sixth samples, did not show such a maximum.The viscosity and weight-average molecular weight of filtrate increased as the reaction progressed.Hydrogen released from hydrogen donor components in the hydrogenated anthracene oil played an important role in the initial stage of coal liquefaction. Judging from the relation between PI value and the amount of released hydrogen, the coal conversion per unit amount of released hydrogen was found to largely depend on coal rank.