| 摘要 |
<p>Purification of liquefied coal using a centrifugal filter and drying at least a part of the filter cake with a gas is improved in that the filtering aid used in this process is recovered from the filter cake (together with coarse particles of the non-liquefied residue) and re-used. The recovery of the filtering aid is carried out on a screening appts. of a wind sifter; or by extraction, or by magnetic sepn. (if a magnetic filtering aid is used e.g. iron or nickel granules. The pref. filtering aids are inorganic, water-soluble salts, such as, sulphates, chlorides, bromides, borates, silicates and carbonates, or oxides. The salts can be recovered by extraction with water. By this method, the filtering aid can be economically recovered and re-used (in the conventional process, the filter cake is discarded together with the filtering aid contained therein).</p> |
