METHOD FOR CLARIFYING PYROLIGNEOUS ACID BY FREEZING AND THAWING

摘要

PROBLEM TO BE SOLVED: To effectively separate constituents and tar from pyroligneous liquid while suppressing heat deterioration, separation, and loss of volatiles by extracting pyroligneous acid from smoke discharged from a charcoal kiln, freezing it by pouring into a freezing container, adding dropwise the thawed product to a recovery container, and clarifying it by filtration. SOLUTION: The extracted pyroligneous acid is stored and poured into a freezing container, and the container is transferred to a refrigeration chamber. As the temperature decreases, the circulation in the liquid can be suppressed, so that the precipitation of fine particles in the tar component can effectively proceed. The freezing treatment is continued until the temperature of the frozen solid is equilibrated with the temperature in the refrigeration chamber. The temperature of the frozen solid is slowly raised to thaw it, and the pyroligneous acid is added dropwise from the frozen solid into a recovery container to recover a molten liquid. The liquid is filtered by means of a filter and clarified. The temperature in the refrigeration chamber is -1 to -500C and controlled according to a staged-temperature method. When the melting treatment proceeds to a certain stage, a small change in the temperature of the added liquid is observed. Eight stages of such change can be distinguished.