Method for extracting, rectifying, purifying and refining trimethylolpropane through multi-tower series connection

The invention discloses a method for extracting, rectifying, purifying and refining trimethylolpropane by multi-tower series connection, which comprises the following steps of: in the production of trimethylolpropane by a calcium method, rectifying, purifying, refining and separating light components by utilizing multi-tower series connection and negative pressure reaction, and treating heavy components by utilizing heat energy of a rectifying system and an acid catalyst reaction; therefore, the trimethylolpropane cyclic formal CTF with economic value is obtained. The method specifically comprises five steps of extraction, a solvent recovery tower, a TMP rectifying tower, a main tower and a flash tower. In the production of trimethylolpropane by a calcium method, more high-boiling-point impurities are generated, and a reaction catalysis rectification technology is adopted, and a proper catalyst is selected to remove part of the high-boiling-point impurities. High-boiling-point impurities are easily dissolved