Novel process for producing tetrahydrofuran by using BDO byproduct waste liquid

The invention relates to the technical field of preparation of tetrahydrofuran, and discloses a novel process for producing tetrahydrofuran by using BDO byproduct waste liquid, which comprises the following steps: 1) pretreating the BDO waste liquid, namely obtaining BDO stock solution, feeding the BDO stock solution into a BDO light component removal tower, heating to 180 DEG C by using 2.5 MPa steam, evaporating water, extracting from the tower top, condensing the tower top water, methanol and other light components in a condenser, and removing the BDO byproduct waste liquid; all the materials are conveyed to a BDO residue tank, residual substances in the tower kettle are conveyed to a stock solution tank through a pump, and the BDO stock solution tank adopts a circulating pump for circulating mixing; and 2) condensing tower top water and a mixture in the step 1) in a condenser, and feeding all the water and the mixture into a BDO residue tank. According to the novel process for producing tetrahydrofuran by