Alternative octane enhancers for 10 ppm sulfur gasoline in China
On July 1, Chinese officials released a second draft for public comment of a China V gasoline fuel quality standard, designed to improve the quality of transportation fuels used nationwide. The second draft includes a 2 mg/L limit on manganese, a heavy metal and neurotoxin that is a key ingredient of the octane additive Methylcyclopentadienyl Manganese Tricarbonyl (MMT). Many developing countries use MMT as a cheap source of fuel octane. Actions have been taken in the United States and Europe to reduce or eliminate MMT from gasoline both to protect public health and to prevent damage to vehicle emissions controls. This limit on manganese would bring Chinese fuel standards in line with European standards for the first time.
To limit the use of manganese, the Chinese government must find alternative sources of fuel octane. The ICCT commissioned a study to characterize octane production in China, quantify the effects of manganese removal on fuel octane, identify alternatives to manganese, and quantify the cost of replacing octane in the most cost-effective manner.
This report presents the results of this assessment. Octane levels will fall 0.9 with adoption of the proposed limit on manganese, as well as an additional 0.4 with adoption of proposed limits on fuel sulfur content for a total loss of 1.3. This octane can be cost-effectively replaced with refinery upgrades and methyl tertiary butyl ether (MTBE), an alternative octane additive derived from crude oil and natural gas components. Average costs across all Chinese refinery groups to replace lost octane would total 0.57 cents (0.03 RMB) per liter with refinery upgrades and MTBE, and 0.66 cents (0.04 RMB) per liter with refinery upgrades alone. Purchase of high octane products on the open market is a third alternative with the potential to reduce costs further, but further study would be required to quantify the amount of octane and cost reduction available through this route.