A method for producing a first intermediate product, comprising the steps of a. providing a feedstock that comprises a first polyester; b. separating the feedstock into at least a first feedstock amount and a further feedstock amount, wherein the first feedstock amount and the further feedstock amount comprise the first polyester; c. transporting i. the first feedstock amount into a first reaction line, and ii. the further feedstock amount into a further reaction line; wherein a reaction line comprises the following steps: I. contacting the first polyester with a further amount of a first organic compound in a volume section V 2, II. reducing a weight average molar mass of the first polyester in the volume section V 2, wherein, after the reduction step has been completed in the volume section V 2, the first polyester has an intrinsic viscosity in the range of 0.10 dL/g to 0.45 dL/g, III. contacting the first polyester with a further organic compound, in a volume section V 3, to obtain a further initial mixture; IV. reducing a weight average molar mass of the first polyester, in the volume section V 3, to obtain a first intermediate mixture, wherein the first intermediate mixture comprises i. a first intermediate product that has an intrinsic viscosity in the range of 0.010 dL/g to 0.090 dL/g, ii. the further organic compound; wherein at least one process parameter varies by at least 10 % between the first reaction line and the further reaction line; the first polyester in the feedstock is in the form of a plurality of fragments, and wherein the following applies: A. at least 60 wt-% of the fragments of the first polyester in the first feedstock amount has a thickness that is less than 1.0 mm, B. at least 60 wt-% of the fragments of the first polyester in the further feedstock amount has a thickness that is 1.0 mm or larger, with the intrinsic viscosity and the wt-% of the fragments with a certain thickness determined according to the methods described herein. a. providing a feedstock that comprises a first polyester; b. separating the feedstock into at least a first feedstock amount and a further feedstock amount, wherein the first feedstock amount and the further feedstock amount comprise the first polyester; c. transporting i. the first feedstock amount into a first reaction line, and ii. the further feedstock amount into a further reaction line; wherein a reaction line comprises the following steps: I. contacting the first polyester with a further amount of a first organic compound in a volume section V 2, II. reducing a weight average molar mass of the first polyester in the volume section V 2, wherein, after the reduction step has been completed in the volume section V 2, the first polyester has an intrinsic viscosity in the range of 0.10 dL/g to 0.45 dL/g, III. contacting the first polyester with a further organic compound, in a volume section V 3, to obtain a further initial mixture; IV. reducing a weight average molar mass of the first polyester, in the volume section V 3, to obtain a first intermediate mixture, wherein the first intermediate mixture comprises i. a first intermediate product that has an intrinsic viscosity in the range of 0.010 dL/g to 0.090 dL/g, ii. the further organic compound; i. the first feedstock amount into a first reaction line, and ii. the further feedstock amount into a further reaction line; I. contacting the first polyester with a further amount of a first organic compound in a volume section V 2, II. reducing a weight average molar mass of the first polyester in the volume section V 2, wherein, after the reduction step has been completed in the volume section V 2, the first polyester has an intrinsic viscosity in the range of 0.10 dL/g to 0.45 dL/g, III. contacting the first polyester with a further organic compound, in a volume section V 3, to obtain a further initial mixture; IV. reducing a weight average molar mass of the first polyester, in the volume section V 3, to obtain a first intermediate mixture, wherein the first intermediate mixture comprises i. a first intermediate product that has an intrinsic viscosity in the range of 0.010 dL/g to 0.090 dL/g, ii. the further organic compound; i. a first intermediate product that has an intrinsic viscosity in the range of 0.010 dL/g to 0.090 dL/g, ii. the further organic compound; at least one process parameter varies by at least 10 % between the first reaction line and the further reaction line; the first polyester in the feedstock is in the form of a plurality of fragments, and wherein the following applies: A. at least 60 wt-% of the fragments of the first polyester in the first feedstock amount has a thickness that is less than 1.0 mm, B. at least 60 wt-% of the fragments of the first polyester in the further feedstock amount has a thickness that is 1.0 mm or larger, A. at least 60 wt-% of the fragments of the first polyester in the first feedstock amount has a thickness that is less than 1.0 mm, B. at least 60 wt-% of the fragments of the first polyester in the further feedstock amount has a thickness that is 1.0 mm or larger, with the intrinsic viscosity and the wt-% of the fragments with a certain thickness determined according to the methods described herein.