Commercial Electrolyzer Technologies

Manufacturer Technology Lower capacity (kg day4) Upper capacity (kg day4) Pressure Location Ref. 

Industrie Haute Techno-logie SA Alkaline 1639.4 1639.4 up to 32 barg Monthey, Switzerland 34 

Peak Scientific Ion exchange membrane 0.01 0.01 0-100 psig Scodand 30 

Schmidlin-DBS AG Membrane 0.005 0.026 1 155 psig Neuheim, Switzerland and Padova, Italy 37 

Siam Water Flame Co. Alkaline 0.647 0.647 unknown Bangkok, Thailand 38 

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Hydrogen as an energy carrier and potentially widely used fuel is attractive because it can be produced easily without emissions by splitting water. In addition, the readily available electrolyzer can be used in a home or business where off peak or surplus electricity could be used to make the environmentally preferred gas. Electrolysis was first demonstrated in 1800 by William Nicholson and Sir Anthony Carlisle and has found a variety of niche markets ever since. Two electrolyzer technologies, alkaline and proton exchange membrane (PEM), exist at the commercial level with solid oxide electrolysis in the research phase. 

A second commercially available electrolyzer technology is the solid polymer electrolyte membrane (PEM). PEM electrolysis (PEME) is also referred to as solid polymer electrolyte (SPE) or polymer electrolyte membrane (also, PEM), but all represent a system that incorporates a solid proton-conducting membrane which is not electrically conductive. The membrane serves a dual purpose, as the gas separation device and ion (proton) conductor. High-purity deionized (DI) water is required in PEM-based electrolysis, and PEM electrolyzer manufacturer regularly recommend a minimum of 1 MQ-cm resistive water to extend stack life. 

Technology Brief Analysis of Current-Day Commercial Electrolyzers, NREL, Golden,... 

Occasionally, the market will swing the other way leaving chlorine in short supply. Fused sodium chloride is commercially electrolyzed in Down s cells to give chlorine and metallic sodium [11]. Sodium production in the U.S.A. has averaged 135,000-150,000 metric tonnes annually since 1968, which represents about a 2-3% contribution to the chlorine supply from this source. In the U.K., it is estimated that as much as 10% of the available chlorine arises from Down s cell technology. Potassium chloride solutions are also electrolyzed for commercial potassium hydroxide, but the contribution to the chlorine supply from this source is even less than from fused sodium chloride electrolysis. 

The aim of this section is to give readers a description of the essential elements which are usually to be found on the technical specifications of a commercial electrolyzer with the most mature forms of technology - namely alkahne and PEM. 

Most of the voltage savings in the air cathode electrolyzer results from the change in the cathode reaction and a reduction in the solution ohmic drop as a result of the absence of the hydrogen bubble gas void fraction in the catholyte. The air cathode electrolyzer operates at 2.1 V at 3 kA/m or approximately 1450 d-c kW-h per ton of NaOH. The air cathode technology has been demonstrated in commercial sized equipment at Occidental Chemical s Muscle Shoals, Alabama plant. However, it is not presentiy being practiced because the technology is too expensive to commercialize at power costs of 20 to 30 mils (1 mil = 0.1 /kW). 

Commercial application of membrane cell technology began in 1975 with the installation of the Nobeoka No 1 (Japan) using Asahi Chemical Co. electrolyzers, Reed Paper (Canada) using Hooker MX electrolyzers and American Can of Canada (Canada) using Ionics Chloromate electrolyzers. By the end of 1982 world capa-... 

Due to the new developments [5] in fuel cell technology—the manufacture of carbon supported platinum catalysts and the use of the Nafion membrane—the cost of bipolar electrolyzers has been reduced a lot, and therefore almost all commercial devices are of this type. In this case, stainless steel or nickel cathodes are used together with nickel anodes in 25%-35% of potassium hydroxide at temperatures between 65°C and 90°C. The hydrogen current density reaches 100-300 mA/cm2 at cell potentials of 1.9-2.2 V, denoting a faradaic efficiency of 80% (losses in peripheries). Usually, a pressurized cell is employed to increase their performance and to reduce the size of the bubbles, thus lowering the overpotential associated with the process. This can be done with appropriate membranes and insulators and by using temperatures near 100°C. 

Three other processes that electrolytically convert HC1 to Cf using metal chloride catalyst are the Schroeder process, using NiCf the Westvaco process, using CuC and the South African process, using MnC. None of these processes is commercial. The Schroeder process illustrates the principles involved in these technologies. The Schroeder process is cyclic and involves two steps. The metal chloride is electrolyzed to produce the metal and chlorine ... 

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