Analysis and Forecast of the Supply and Demand Situation of MTBE and Alkylated Gasoline in Our Country

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Analysis and prediction of the supply and demand situation of MTBE and alkylated gasoline in China. MTBE is an ether product of isobutylene and methanol, with isobutylene primarily found in liquefied gas. To reduce production costs, industrially, refined C4 containing isobutylene is directly subjected to a catalytic addition reaction with methanol; after the reaction, the unreacted C4 and methanol are separated to yield fuel-grade MTBE. This type of MTBE has a high sulfur content; through comparative analysis of the raw materials, it was found that under normal conditions, all the sulfur in MTBE originates from raw material C4. The raw material C4 for MTBE has various sources, primarily coming from the C4 components in catalytic cracking, coking, and liquefied petroleum gas produced by ethylene plants. The C4 obtained from liquefied petroleum gas in ethylene plants undergoes strict desulfurization during the production process. However, liquefied petroleum gas derived from catalytic cracking and coking units, after refining and desulfurization, typically has a sulfur content of over 20 ppm. Moreover, after C3 is removed through gas fractionation and the material enters the MTBE plant, the sulfur content in the MTBE product further increases (studies have shown that the sulfur concentration increases by 3 to 6 times throughout the process of producing MTBE from desulfurized liquefied petroleum gas). The sulfides in MTBE products mainly originate from C4 feedstocks produced via catalytic cracking and coking. Currently, the sulfur content in MTBE products produced from mixed C4 as raw material varies considerably, typically ranging from 80 to 200 ppm, with some values reaching as high as 2000 to 3000 ppm. When implementing the National III gasoline standard, by strengthening management and monitoring during liquefied gas desulfurization, the sulfur content in MTBE can generally be kept at around 150 ppm. However, as national standards impose increasingly strict limits on the sulfur content in gasoline, the emission standards for Level 4 and Level 5 require that the sulfur content in gasoline be below 50 ppm and 10 ppm respectively. Existing advanced desulfurization technologies can help bring the sulfur content in gasoline to these required levels. But current liquefied gas desulfurization technologies find it difficult to reduce the sulfur content in MTBE to below 50 ppm, and it is even more challenging to achieve a level of less than 10 ppm. Although there are many MTBE plants under construction or planned in our country, domestic C4 resources will become increasingly scarce in the future, resulting in a limited actual operating rate for these MTBE plants. At the same time, due to the diversification of C4 sources, low-sulfur C4 resources will become even rarer; as a result, the amount of MTBE that can meet the gasoline National IV and National V standards will not be large. With the continuous improvement of gasoline standards for vehicles and the reduction in sulfur content, there is an increasing demand for technologies for producing low-sulfur MTBE, and such low-sulfur MTBE will be in high demand.