Method for utilizing waste liquid from cyclopentadiene production using C9 distillate

The invention relates to a utilization method for using the produced waste liquid generated by preparing cyclopentadiene by adopting c_9 distillation. The method comprises the following steps: the waste liquid is subjected to polymerization in the presence of a catalyst, wherein the reaction temperature is between 50 and 90 DEG C, and the reaction time is between 2 and 7 hours; the catalyst is a composite catalyst; boron trifluoride etherate is taken as a main catalyst, and alkyl benzene provided with alkyl betwen C2 and C4 is taken as an auxiliary catalyst; the weight ratio of the main catalyst to the auxiliary catalyst is 1 to 1-5; the amount of the catalyst is based on the amount of a reactant and calculated according to the amount of the main catalyst, and is between 1 and 3 weight percent; polymerization products are subjected to alkaline washing to neutrality, standing and delamination, and oil-phase materials are taken; the oil-phase materials are subjected to vacuum distillation for removing light com