A system of hydrogen-powered vehicles with liquid organic hydrides

Abstract

A complete system for storing and using energy in the form of liquid organic hydride is discussed. The recyclable liquid carrier is ⇄ The system is called MTH for M ethylcyclohexane, T oluene, H ydrogen.) All the technical processes proposed for this system are well established. The dehydrogenation reaction occurs in a catalytic reactor (>400°C, approx. 20 bar) on the vehicle. The hydrogenation occurs in a regional plant, servicing approx. 195 vehicles in which the hydrogen is produced by the electrolysis of water [22 MW (el)] and catalytically reacted with toluene, transforming it into methylcyclohexane. As a reference vehicle a 17 ton lorry having a 150 kW (mec) engine and an operating range of approx. 250 km per day for 250 days per year is taken. The catalytic reactor for the dehydrogenation on the vehicle has a volume of approx. 501. The tank for methylcyclohexane, the carrier of hydrogen, is approx. 7101. (equivalent: 100 kg gasoline). The cold start is based on the direct burning of toluene. The overall energy consumption is split up as 90% from hydrogen (electrical energy) and 10% from the direct burning of toluene (fossil fuel). The complete MTH system after 30 years with approx. 15,000 lorries consumes 5.4 TWh (el) per year during the night and at weekends during 235 days of ‘summer’. A seasonal storage for the rest of the year (‘winter’ approx. 115 days) is included here. The calculated economic parameters for the proposed MTH-system are as follows (prices 1981): • the cost of an equivalent 11. gasoline 0.70 SFr/1, assuming the electricity price, during summer night 0.04 SFr/(kWh); • the cost of an equivalent 11. heating oil 0.31 SFr/l (low price because of difficulties of selling during summer); • the capital cost for the system (excluding annual storage), calculated for an equivalent barrel of oil 75 000 SFr per barrel daily; • corresponding capital cost of MTH-system equals (prices 1981): ◦ approx. 26 SFr per barrel-equivalent, that is ◦ approx. 12.5 US $ per barrel-equivalent over a period of 10 years.