On-site DME generation from methanol for pilot injection in CI engines

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Conference Proceeding

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Dual fuel (CI) engines provide an excellent means of maintaining high thermal efficiency and power while reducing emissions, particularly in situations where the primary fuel does not exhibit good auto-ignition characteristics. This is especially true of diesel engines operating on natural gas; usually in stationary applications such as distributed power generation. However, because two fuels are needed, the reliability of the engine is compromised. Therefore, this paper describes the first phase of a project that is to eventually manufacture dimethyl ether (DME) from natural gas and supply it to the pilot injector of a dual fuel engine. A chemical pilot plant has been built and operated, demonstrating an intermediate step in the production of DME from natural gas. DME is manufactured from methanol for pilot injection into a dual fuel engine operating with natural gas as the main fuel. Presently, 0.38 kilogram of DME fuel is produced per kilogram of methanol feed into the process via a catalytic reaction. Future improvements in separation efficiency should improve this to ∼0.53 kg DME / kg methanol feed. The plant is capable of supplying DME of sufficient fuel quality (i.e., DME containing < 10 wt% H2O and < 10 wt% methanol) to the fuel injection system at a pressure of 15 bara and a flow-rate of 1.5-2.0 kgDME/hr. This would be enough to provide a 1/2 LHV% pilot of DME to a 1000 bkW dual fuel engine with 42% thermal efficiency. Byproducts of the process situate into two liquid phases, each containing amounts of DME, methanol, and water. Copyright © 2003 SAE International.

Publication Title

SAE Technical Papers