The BASF NMP-based butadiene extraction process, licensed by Lummus Technology since 1990, is the preferred technology for the production of high purity 1,3-butadiene from crude C4 cuts. The technology is successfully applied in 41 plants worldwide, with a total capacity exceeding four million tons per year. The NMP-based butadiene process uses n-methyl-pyrrolidone (NMP) as solvent. Unlike the other solvents used for butadiene extraction, the aqueous mixtures of NMP are not corrosive, thereby allowing the use of carbon steel as construction material without the addition of corrosion inhibitors. This process is particularly suitable for C4 streams from high severity cracking where the acetylene levels may be high (>3%). It produces a 1,3-butadiene product of 99.7 wt% purity while recovering more than 99% of the 1,3-butadiene contained in the feed. It also produces a raffinate-1 product that consists of a mixture of butanes and butenes with a butadiene content as low as 40 ppm wt.
Benefits
- Low investment costs—NMP and its water mixtures are non-corrosive and low-fouling. Carbon steel construction is used throughout the entire unit, plus the dividing wall column and packing are used in the extractive distillation section
- Low operating cost—Efficient heat recovery systems and optimal process design
- Fewer shutdowns / lower maintenance cost—Operating periods exceeding five years between turnarounds can be achieved due to high solvent stability, an effective solvent regeneration system and an effective fouling inhibitor system
- Environmentally friendly design—NMP is the least toxic solvent that is easily treated by conventional biological degradation
- Low operating cost—Low solvent losses due to NMP's stability to hydrolysis and thermal decomposition as well as its high boiling point
- High value product—All industrial C4 feeds can be processed, regardless of their 1,3-butadiene content, to obtain a high-purity butadiene product