Low-temperature distillation of coal

Claim 1

IN THE PROCESS FOR LOW TEMPERATURE DISTILLATION OF COAL TO YIELD GASEOUS AND LIQUID PRODUCTS AND A SOLID DISTILLATION RESIDUE COMPOSED OF PARTICLES HAVING SUBSTANTIALLY THE SAME VOLATILE MATTER CONTENT, THE STEPS COMPRISING CIRCULATING FINELY DIVIDED FRESH COAL OF A PREDETERMINED PARTICLE SIZE CONSISTENCY THROUGH A DISTILLATION ZONE, CIRCULATING PREHEATED FINELY DIVIDED PREVIOUSLY DISTILLED COAL THROUGH SIAD DISTILLATION ZONE IN DIRECT HEAT EXCHANGE RELATION WITH SAID FRESH COAL SO AS TO FORM A MIXTURE OF SOLID PRODUCTS WITH SAID FRESH COAL, THE HEAT REQUIRED TO EFFECT DISTILLATION OF SAID FRESH COAL BEING DERIVED SOLELY FROM SAID PREVIOUSLY DISTILLED COAL, SAID PREVIOUSLY DISTILLED COAL HAVING A PARTICLE SIZE CONSISTENCY SUFFICIENTLY DIFFERENT FROM THAT OF SAID FRESH COAL TO PERMIT ITS READY SEPARATION FROM THE DISTILLATION RESIDUE OF SAID FRESH COAL, THE TOTAL AMOUNT OF DISTILLATION RESIDUE INCLUDING PREVIOUSLY DISTILLED COAL PRESENT IN SAID DISTILLATION ZONE AT ANY ONE TIME BEING SUFFICIENT TO PREVENT AGGLOMERATION OF SAID FRESH COAL BY DILUTION THEREOF, RECOVERING THE GASEOUS AND LIQUID PROUDCTS OF DISTILLATION, SEPARATING THE DISTILLATION RESIDUE OF SAID FRESH COAL FROM SAID SOLID PRODUCTS, CIRCULATING AT LEAST A PORTION OF THE REMAINING SOLID PRODUCTS TO A COMBUSTION ZONE WHERE THE TEMPERATURE IS RAISED BY PARTIAL OXIDATION, RECYCLING AT LEAST A PORTION OF THE PARTIALLY OXIDIZED SOLIDS TO THE DISTILLATION ZONE TO SERVE AS SAID PREHEATED PREVIOUSLY DISTILLED COAL AND REPLENISHING SAID RECYCLED PREVIOUSLY DISTILLED COAL WITH A PORTION OF THE DISTILLATION RESIDUE.