Plant for converting plastics into petrochemical products, comprising a cracking reactor (V.1) for a pyrolysis reaction or thermochemical process, wherein the plastics is converted into at least gasified pyrolysis products and char, and further comprising a separate combustor (V.2), the cracking reactor (V.1) comprising a reactor vessel with a bottom section (Section I), a middle section (Section II) and a top section (Section III), the reactor vessel further comprising a plastics inlet port, a particles inlet port, a pyrolysis products outlet port discharging from the top section (Section III), and a char and particles outlet port discharging from the bottom section (Section I), the combustor (V.2) comprising a char and particles inlet port, a combustion air inlet port, and a combustion products and particles outlet port, the char and particles outlet port of the cracking reactor (V.1) being connected to the char and particles inlet port of the combustor (V.2), and the combustion products and particles outlet port of the combustor (V.2) being connected to the particles inlet port of the cracking reactor (V.1), the cracking reactor (V.1) and the combustor (V.2) therefore being part of a particles loop which contains a multitude of solid particles, such that during operation the particles are cycled from the cracking reactor (V.1) to the combustor (V.2) and back, wherein the cracking reactor (V.1) is designed such that mixing in the cracking reactor (V.1) is mainly promoted by a flow of said particles fed a the top of the cracking reactor (V.1) essentially in counter-current with a flow of the pyrolysis products, without need of mechanical mixing devices, characterized in that the plastics inlet port is a plastic melt flow inlet port oping into the bottom section (Section I), wherein the plastic melt flow inlet port feeds a plastic melt flow into an annular chamber which opens into the middle section (Section II) of the reactor vessel via a number of nozzles, which are capable of injecting high viscous plastic melt with high pressure into the vessel body, wherein the pressure is in the range from 50 to 80 bar or even greater, wherein the particles inlet port leads into a channel which at least in part opens into the middle section (Section II), and wherein said channel is realized as an interspace between an external reactor vessel wall and a heat conductive internal partition wall. the cracking reactor (V.1) comprising a reactor vessel with a bottom section (Section I), a middle section (Section II) and a top section (Section III), the reactor vessel further comprising a plastics inlet port, a particles inlet port, a pyrolysis products outlet port discharging from the top section (Section III), and a char and particles outlet port discharging from the bottom section (Section I), the combustor (V.2) comprising a char and particles inlet port, a combustion air inlet port, and a combustion products and particles outlet port, the char and particles outlet port of the cracking reactor (V.1) being connected to the char and particles inlet port of the combustor (V.2), and the combustion products and particles outlet port of the combustor (V.2) being connected to the particles inlet port of the cracking reactor (V.1), the cracking reactor (V.1) and the combustor (V.2) therefore being part of a particles loop which contains a multitude of solid particles, such that during operation the particles are cycled from the cracking reactor (V.1) to the combustor (V.2) and back, wherein the cracking reactor (V.1) is designed such that mixing in the cracking reactor (V.1) is mainly promoted by a flow of said particles fed a the top of the cracking reactor (V.1) essentially in counter-current with a flow of the pyrolysis products, without need of mechanical mixing devices, characterized in that the plastics inlet port is a plastic melt flow inlet port oping into the bottom section (Section I), wherein the plastic melt flow inlet port feeds a plastic melt flow into an annular chamber which opens into the middle section (Section II) of the reactor vessel via a number of nozzles, which are capable of injecting high viscous plastic melt with high pressure into the vessel body, wherein the pressure is in the range from 50 to 80 bar or even greater, wherein the particles inlet port leads into a channel which at least in part opens into the middle section (Section II), and wherein said channel is realized as an interspace between an external reactor vessel wall and a heat conductive internal partition wall.