Multistage thermolysis method for safe and efficient conversion of treated wood waste sources

A method for converting a treated wood waste source to a Clean Fuel Gas and Biochar comprising:

• inputting a treated wood waste source into a thermolysis system;
• wherein the thermolysis system comprises a primary reactor and at least a secondary reactor, said reactors having a process temperature between about 300° C.-1000° C., at least two gas scrubbers, an oil/water separator, and an oil/tar cracker;
• wherein the treated wood waste source comprises toxic compounds comprising inorganic and/or organic preservatives present in the waste source in an amount of at least 20 wt-%, wherein the inorganic and/or organic preservatives comprise one or more of creosote, chlorinated phenols, borates, copper, zinc, arsenic, chromium, pentachlorophenol (PCP), copper naphthenate, ammoniacal copper zinc, mixtures of coal tar oils, nitrides or other salts;
• destroying and/or removing the toxic compounds in the waste source;
• and
• generating outputs of the thermolysis system comprising Clean Fuel Gas and Biochar,
• wherein the reactors generate tars and oils which are thereafter separated from the Clean Fuel Gas in the at least two gas scrubbers, thereafter, cracked in the oil/tar cracker, and sent back to the secondary reactor to generate more of the Clean Fuel Gas and no tars and oils remain in the outputs;
• wherein the Clean Fuel Gas is substantially-free of halogenated organic compounds;
• and
• wherein the Biochar is substantially-free of polycyclic aromatic hydrocarbons, dioxins and furans.