High-pressure alkaline electrolyser

Keywords autonomous wind-hydrogen station (AWHS), wind power station (WPS), high-pressure alkaline electrolyser (HPAE)... 

The further improvements of the described above solution of the high-pressure alkaline electrolyser mainly concern the optimisation of the composition and preparation technology of the active electrodes. So, the application of the electrochemically-deposited materials for making the active electrodes allows to significantly reduce the voltage drop (to 0.6-1.5 V, as compared to 1.7-2.2 V which is specific value for the conventional low-temperature electrolysers). In turn, the increase of the output pressure to 200 bar makes it possible to increase the operation temperature to 150 °C that results in the reduction of the overpotential. It increases the efficiency reducing the power consumption for the production of 1 m3 H2 and 0.5 m3 02 to 4.1 kW h. 

The integration of the advanced wind power station and the novel high-pressure alkaline electrolyser makes it feasible to develop an efficient autonomous wind-hydrogen station (Figure 1). The station has estimated power of 200 kW, and, being operated at rated conditions, can produce 100 kg (1100 m3) of hydrogen per a day. It corresponds to... 

High-pressure alkaline electrolyser PEM electrolyser SOEC... 

Alkaline electrolysers are at an industrial stage, especially commercialized for on-site production of ultrapure hydrogen for industrial applications. In general, this hydrogen is needed at low to moderate pressure, and the cost demand is set in comparison to the alternative, which is in general the supply by tube trailers. High purity water is fed to the electrolyzer. State-of-the-art commercial alkaline electrolysers typically operate at HHV systems efficiency of 60-75% [44], Current... 

Compared to alkaline electrolysis, material costs are high for SPE electrolysers. The advantage of the SPE technology lies in a higher gas quality - especially in part load operation. Using a solid electrolyte also makes higher pressure possible as the absence of alkaline solution provides better sealing options. Some suppliers of SPE electrolysers are listed in Table 5.2. 

The modem alkaline and PEM electrolysers are characterised by productivity from few tens litres to several hundreds cubic metres per hour at output pressure 1 to 50 atm. Some electrolysis plants can produce up to 4 tons of hydrogen under pressure of 7 atm per a day. The typical current density and efficiency are of 1.6 A/cm2 and 60-75% (power consumption 4-5 kW-h/Nm3 H2), respectively. Nowadays, high operating pressure, up to 200 atm, is used to increase the efficiency of electrolysers. Also, the electrodes covered by noble metals and advanced electrolytes are applied. In the future it is possible to increase the efficiency of the electrolysers up to 80-90% [4-6]. 

---