Application: To decompose commercial-grade methyl tertiary butyl ether (MTBE) feed to high-purity isobutylene and commercial-grade methanol. Isobutylene purity of greater than 99.9% is achievable.
Description: By utilizing the CDIB technology, commercial MTBE feedstock is first fractionated to remove light ends and heavies. The highpurity MTBE is then fed to the decomposition reactor where MTBE is converted to isobutylene and methanol. The decomposition reaction takes place in vapor phase and is performed with high selectivity. Heat of reaction is supplied by medium-pressure steam. The methanol is extracted from the reactor effluent in a water wash. The aqueous stream is fractionated to recover the wash water and MTBE for recycle, and to produce high-quality methanol. The water-washed reactor effluent is fractionated to remove heavies (including MTBE for recycle) and light ends, leaving a high-purity (>99.9%) isobutylene product.
Economics: The CDIB technology can be provided in a stand-alone unit or can be coupled with a CDMtbe unit to provide a very efficient integrated unit. Capital and operating costs are reduced when compared to separate units. Isobutylene product purification can be simplified by providing recycle to the MTBE unit. CDIB methanol recovery can be simplified by combining it with MTBE unit methanol recovery in common equipment.
Process advantages include:
• Simple and effective control
• High MTBE conversion
• High isobutylene selectivity
• High flexibility
• Low capital cost
• High purity isobutylene
• No corrosion problems
• Significant operating experience.