NEW HIGH CONVERSION ETHERIFICATION PROCESS TESTED AND PATENTED

Phillips Petroleum Co. has developed and patented a high-conversion etherification process that, in extensive pilot-plant tests using commercial feedstocks, has converted more than 99% of isobutylene to MTBE and more than 90% of isoamylene to TAME. Phillips says the high conversion levels result from very specific unit configuration and process operating parameters which it developed as a result of pilot plant testing.

Dec. 27, 1993

2 min read

Phillips says the high conversion levels result from very specific unit configuration and process operating parameters which it developed as a result of pilot plant testing.

Depending on the hydrocarbon fraction and alcohol used, the process can produce any of four ethers--methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), or tertiary amyl ethyl ether (TAEE). Refiners can choose the ether that best utilizes their C4 and C5 feedstocks.

The new process improves reactive isoamylene conversion rates by as much as 22% over conventional, fixed-bed units, according to Phillips. It also reduces the need for alcohol-recovery operations by promoting more complete reaction of olefins and alcohol. Although data on component kinetics and nonideal interactions between the alcohols and hydrocarbon streams are not generally available, Phillips developed a data base to accurately model these systems.

PROCESS

A block diagram of the process is shown in Fig. 1.

The process uses standard refinery, unit equipment. The use of conventional distillation and liquid-phase, downflow, fixed-bed reactors avoids the need for specialized equipment.

Alcohol-to-olefin ratios and operating conditions are closely controlled to minimize the formation of byproducts such as tertiary amyl alcohol, tertiary butyl alcohol, dimethyl ether, and diethyl ether.

The system also permits sequential catalyst changeout in the two reactors. This means that the units do not have to be shut down, thus permitting continuous ether production.