Method for pyrolysis of waste material in an industrial process

A method for pyrolysis of a mass of waste material, comprising:

• providing a screw arrangement adapted to supply heat to said mass by mechanical shear;
• providing a connecting element, connected to the exit of said screw arrangement;
• providing a reactor after said connecting element, adapted to supply heat to said mass in the absence of oxygen by heating the reactor wall with an external heat source;
• heating said mass in said screw arrangement to an exit temperature, wherein said mass is at least partially melted;
• transporting said mass through said connecting element;
• thermally degrading said mass in said reactor wherein carbon-carbon bonds in said mass are broken by pyrolysis and volatile hydrocarbons are formed,
• wherein said method further comprises:
• increasing the pressure of said mass through said screw arrangement, to an exit pressure;
• expanding said mass in said connecting element, with a pressure drop from said exit pressure to a lower pressure;
• wherein said mass is brought into an extreme condition at said exit temperature and exit pressure by said screw arrangement, such that during said pressure drop pyrolysis occurs, thereby forming gaseous hydrocarbons within said connecting element.

A system for pyrolysis of a mass of waste material, comprising:

• a screw arrangement adapted to:
• supply heat to said mass, at least in part by mechanical shear, so that said mass present in said screw arrangement is heated to an exit temperature, wherein said mass is at least partly melted, and to
• increase the pressure of said mass, to an exit pressure at the exit of said screw arrangement;
• a connecting element connected to the exit of said screw arrangement;
• a reactor placed after said connecting element, adapted to supply heat to said mass in the absence of oxygen by heating the reactor wall with an external heat source, so that said mass present in said reactor thermally degrades, whereby carbon-carbon bonds in said mass are broken by pyrolysis and volatile hydrocarbons are formed, wherein
• said screw arrangement is adapted to bring said mass in an extreme condition at said exit pressure and said exit temperature, such that during an expansion of said mass in said connecting element pyrolysis occurs, thereby forming gaseous hydrocarbons in said connecting element;
• said screw arrangement comprises three different outlet ports, adapted to evacuate water vapor, gases comprising halogens, and gaseous hydrocarbons from said screw arrangement;
• said connecting element comprises a closed wall and is adapted to transport said mass comprising gaseous hydrocarbons formed during said expansion, by allowing said mass to flow through said connecting element in presence of said exit pressure.