RE: Methanol16 Dec 2021 14:21
Johnny,
I was more interested in these bits:
Methanol is also a promising candidate for hydrogen storage, as well the utilization of CO2 via hydrogenation [21]. The adoption of methanol is strongly correlated with the idea of power-to-product (P2X), which utilizes surplus electricity to produce chemical fuels. Hydrogen can be released from methanol through thermolysis, steam reforming and partial oxidation [21]. However, the adoption of methanol to store hydrogen leads to environmental problems in the utilization site because of the release of CO2 when methanol is directly utilized or decomposed. This leads to a non CO2-free energy system. In addition, the separation of CO2 is also energy intensive. The established CO2 separation based on absorption using amine solution consumes approximately 1.1 kWh/kg-CO2 [22].
Liquid ammonia is able to store hydrogen in volumes much higher (121 kg-H2/m3) than liquid hydrogen (70.8 kg-H2/m3), which is about 1.7 times as high. Liquid ammonia can be stored at relatively low pressure (0.99 MPa at a temperature of 25 °C), which is significantly lower than that of compressed hydrogen. However, in terms of physical density, liquid ammonia has the higher density (600 kg/m3) than compressed and liquid hydrogen, leading to heavier storage and transportation.
Methanol is a strong competitor for the storage of hydrogen. It has higher energy density than ammonia (20.1 MJ/kg compared to 18.6 MJ/kg). However, it has both lower gravimetric and volumetric hydrogen contents than ammonia (12.5 wt% and 99 kg-H2/m3 compared to 17.8 wt% and 121 kg-H2/m3, respectively)