Method for extracting methylnaphthalene in C10 aromatics

The invention discloses a method for extracting methylnaphthalene in C10 aromatics. The concrete process comprises charging the raw material C10 aromatics by employing a continuous intermediate charging manner, and starting to heat when the liquid level reaches the 1/3 position; controlling the tower top D-1 temperature to be 203.5-206.1 DEG C, the side-stream D-2 temperature to be 221.5-223.6 DEG C, the side-stream D-3 temperature to be 244.7-246.5 DEG C, and the tower kettle D-4 temperature to be 252.5-256.6 DEG C; after separation, obtaining light C10 compositions at the tower top, obtaining a durene and naphthalene enriched solution at the side-stream D-2, obtaining a methylnaphthalene enriched solution at the side-stream D-3, and obtaining heavy C10 compositions at the tower kettle D-4; and condensing and crystallizing the side-stream D-3 composition, so as to obtain methylnaphthalene. The method is short in period, simple in operation, low in energy consumption and high in relative yield. Under the conditions that the continuous side-stream rectifying tower temperature, the charging/discharging rate and the reflux ratio are determinate, the methylnaphthalene content in the methylnaphthalene enriched solution can be improved to 88 wt% or more at one time, the yield reaches 86% or more, and after continuous crystallization, the methylnaphthalene crystal purity is 96% or more, and the yield is 86% or more.