| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1999: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Research Abstract |
A new oxidative degradation method was developed for separating hemicellulose, cellulose and lignin from an oil palm shell waste, and for converting them into valuable chemicals. The method is basically a two-step process, in which the shell pretreated in a hot water at 180 ℃ was oxidized with 30%-H_2O_2 at 60 ℃ (first stage oxidation) under ambient pressure with or without a Fe catalyst. To increase the product yield and selectivity, a second stage oxidation of the water-soluble components obtained from the first stage oxidation was also performed in the presence of the Fenton reagent at 25 ℃. Through the hot water treatment hemicellulose in the palm oil shell was successfully recovered as saccharides, leaving lignin and cellulose. Through the first stage oxidation without the Fe catalyst lignin was converted to water-soluble compounds containing small molecular weight fatty acids such as HCOOH and CH_3COOH, and almost pure cellulose was recovered in 22 % of yield on carbon basis. Aft
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er the second stage oxidation, the yield of small molecular weight fatty acids reached 30 wt.% on the oil palm shell basis.
In the above method, it is meaningful and useful to find another methods to utilize the water-soluble compounds (WSL) that are obtained in 48 % yield as intermediates from the oil palm shell. Since the water-soluble organic compounds consist of partly oxidized lignin, their gasification rate is expected to be larger than the gasification rate of the original shell. We examined the possibility to utilize the water-soluble compounds as a feedstock for the gasification by comparing the gasification rates among WSL, the original oil palm shell (OPS) and the shell pretreated by hot water (HTS) using the so-called temperature-programmed reaction (TPR) method in a helium and oxygen gas mixture.
The gasification of OPS and HTS proceeded in two steps. It is supposed that the first stage and the second stage gasifications correspond to the gasifications of cellulose and lignin, respectively. On the other hand, WSL was rapidly gasified below 340 ℃. From the in-situ FTIR measurements it was found that the lignin decomposed into cross-linked structure before being gasified for HTS.On the other hand, WSL was gasified without the cross-linking reaction developing aromatic ring structure. The gasification rate of WSL increased with the progress of conversion and was 500 times larger than that of the oil palm shell at the conversion of 0.9.
Thus, the proposed method was expected to be a new route for converting low grade resources into valuable chemicals. Less
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