Low cost polyester process using a pipe reactor

Component for introducing the method for reacting liquid and/or process liquid, comprising the following steps: a) providing a inflow and liquid circulation loop, wherein the inflow and reacting the fluid connection; (b) is wherein the circulation loop to recycle at least a portion of corresponding to the step (a) reacting liquid, by said circulation loop to the reaction liquid in the circulating liquid; (c) is at least pressure of the device to the circulation loop at least one of such a step (b) is reduced pressure of the circulating liquid; The topical or is located in the step (c) pressure of the device is (d), fed to the component a circulation loop, wherein from wherein the introduction of the reaction liquid.