Process for the pyrolysis of refuse

Claim 1

A process for the pyrolysis of refuse comprising: (a) subjecting the refuse to carbonisation in a rotary kiln in the substantial absence of air to produce raw carbonisation gases at a temperature of between about 300° and 450° C. and at a calorific value of between 1000 and 3500 kcal/standard cubic meter (moist), and solid residues; (b) separating said raw carbonisation gases from said solid residues; (c) dividing said raw carbonisation gases into a first part comprising between about one-fifth and one-half of the total amount and a second part comprising between about one-half and four-fifths of the total amount of said raw carbonisation gases; (d) completely burning said first part of the raw carbonisation gases to produce hot flue gases with a solid carbon content of less than 50 mg/standard cubic meter; (e) mixing said hot flue gases with said second part of the raw carbonisation gases to obtain a cracking temperature of between about 900° and 1100° C.; (f) feeding said mixture of gases through a free-flow, non-catalytic reactor at a pressure of between about 0.7 and 1.2 atm, a velocity of between about 1 and 30 meters per second, and a residence time of between about 0.5 and 3 seconds to crack the long chain organic constituents in said mixture of gases, (g) the cracking temperature being so selected that for a predetermined residence time the content of condensable organic compounds in the cracked gases is less than 0.2 g/standard cubic meter, (h) the division of said raw carbonisation gases being so selected that for a predetermined calorific value of said raw carbonisation gases said selected cracking temperature is obtained; and (i) cooling said cracked gases to a temperature just above their dew point at a rate of at least 125° C. per second.