摘要 |
<p>A method and apparatus for thermo-mechanical pulping which involves contacting wood chips with gaseous steam at ambient pressure conditions to thereby raise the temperature of the chips close to that of the steam, followed by compacting the steam treated chips with a relatively high compaction ratio to thereby eliminate much of the water content as well as much of the pitch present, contacting the chips with pressurized steam sufficient to raise the temperature to at least the lignin softening point, and thereafter refining the resulting chips at superatmospheric pressures.</p> |