Abstract: An improved process for the treatment of aqueous effluents containing strong anions such as sulphate, nitrate, chlorides and fluorides wherein the aqueous effluent is subjected to a biological purification process is described. According to the process, aqueous effluent such as those obtained by condensation of gases present in a coal gasification plant and containing these anions and others in a combined concentration of at least 2 mval/l and organic contaminants in a concentration of at least 1000 mg/l are subjected to the biological purification followed by separation of water from solids of the effluent. Thereafter, the water is subjected to anion exchange in an anion exchanger against hydrogen carbonate ions and at least part of the so-treated water is recycled to the aqueous effluent so as to be present therewith during the biological purification. By such a process the biological purification can be conducted at an optimum pH such as a pH in the range of 6 to 8. CO.sub.3 /HCO.sub.

Abstract: The invention provides a process and an apparatus for hydrogenative liquefaction of coal to produce high yields of gasoline fraction and optional yields of diesel and residue fraction, all of superior quality. The coal is slurried and digested in two separate and distinct streams. The pasting oil of the first stream is heavy residue fraction derived to a substantial extent from the second stream, preferably mixed with light oil derived partly or wholly from the first stream. The pasting oil of the second stream is middle oil derived from the fractionated discharge of the first stream, any shortfall being made up from the discharge of the second stream. A high degree of flexibility is possible by varying the ratio of coal fed to the respective streams between 3:1 and 1:3, and individual manipulation of the process parameters within each stream in respect of pressure, temperature, catalyst, residence time, pasting oil composition and coal quality.

Abstract: The invention provides a process and an apparatus for hydrogenative liquefaction of coal to produce high yields of gasoline fraction and optional yields of diesel and residue fraction, all of superior quality. The coal is slurried and digested in two separate and distinct streams. The parting oil of the first stream is heavy residue fraction derived to a substantial extend from the second stream, mixed with light oil derived partly or wholly from the first stream. The pasting oil of the second stream is middle oil derived from the fractionated discharge of the first stream, any shortfall being made up from the discharge of the second stream. A high degree of flexibility is possible by varying the ratio of coal fed to the respective streams between 3:1 and 1:3, and individual manipulation of the process parameters within each stream in respect of pressure, temperature, catalyst, residence time, pasting oil composition and coal quality.

Abstract: The invention provides a process for the liquefaction of coal. The comminuted coal is slurried in a solvent or pasting oil and digested, normally under hydrogen pressure, e.g. of 50 to 250 atmospheres partial pressure, under catalytic conditions, at temperatures between about 380.degree. and 500.degree. C., preferably 400.degree. to 470.degree. C. and residence times between about 10 and 100 minutes. The solvent or pasting oil is obtained wholly or mostly by recycling from the distilled fractionation of the reaction products. The solvent system comprises a light fraction in the boiling range up to 200.degree. C. and a heavy residue fraction, boiling mainly above 450.degree. C., there being a more or less well-defined lack of solvent in a boiling range intermediate between 200.degree. and 450.degree. C. Preferably less than 20%, e.g. 5% or less of the solvent system boils between 200.degree. and 450.degree. C. The ratio of low boiling to high boiling solvent is preferably from about 3:1 to 1:3.