Technology

Introduction

The ZEON GPB process is the technology for extraction of 1,3-Butadiene from the C₄ fraction produced in naphtha cracking. DMF has excellent dissolving selectivity for butadiene among other C₄ hydrocarbons. The rubbery polymerization problem is completely solved by dosing some easily available inhibitors into the solvent. Popcorn polymer formation is also inhibited by preventing leakage of oxygen into the process by designing higher operating pressure than atmospheric by using a non-aqueous solvent and by the inhibitor at the high concentration level of butadiene. The typical butadiene purity is higher than 99.6 % with less than 20 ppm of acetylene.

Process Description

The crude C₄ and the DMF solvent are fed to 1^st extractive distillation column where the C₄ stream is separated into the C₄ raffinate-1 from top and the bottom stream which contains butadiene/acetylene in the DMF solvent. The butadiene/acetylene rich solvent is fed to 2^nd extractive distillation column where mainly vinylacetylene is removed. The top stream is sent to the butadiene purification section where the remaining acetylene is removed and purified 1,3-butadiene is produced using two distillation columns. The lean solvent from two strippers is cooled via heat recovery prior to being sent back to the extractors.

Case Study

The table below shows the economics for 140,000 ton per year of product butadiene.

Source

kanata-jp.net, Butadiene Recovery