Why are Chinese MTBE producers shifting toward deep etherification technology?

Why are Chinese MTBE producers shifting toward deep etherification technology?
Sinopec Qilu's independently developed deep etherification technology completed its first industrial calibration at a 90,000 ton per year MTBE unit in the Zhongke Refining and Chemical Dongxing branch. The driver is downstream quality: conventional refinery-type MTBE units leave too much isobutylene in the etherified C4, which fails to meet feed requirements for subsequent 1-butene production. Deep etherification lifts isobutylene conversion so the raffinate meets specification. The payoff is lower retrofit and operating cost for existing units and a reliable C4 route to 1-butene. For buyers, it signals that MTBE units are being repositioned as integrated C4 upgrading assets rather than pure blending-component plants.