In regions where natural gas is abundant, and CCUS is possible, this natural-gas intensive process for hydrogen production can be viable. The South Eastern United States or the West coast of Norway are two example locations that would fit these conditions. The emergence of abundant, low-cost renewable power from super- scale, ideally located onshore and offshore wind farms and GW scale solar parks allows for the use of electricity in new ways to reduce our reliance on fossil energy sources. Microwave catalytic reforming – CO 2 emissions reduction through electrification Microwave energy is produced from electricity and is used in our homes to heat food. Radio communications masts also transmit information using microwave frequencies. Industrial microwaves are used for drying pharmaceutical powders, cereal grains and timber. Microwaves are now also being used to provide the energy to drive steam methane reformers. Jan Boshoff is the CEO of Nu:ionic Technologies, a company based in New Brunswick in Eastern Canada. Boshoff says that “using microwaves from renewable power instead of burning natural gas or biomethane to create the energy required for the reforming reaction can reduce gas consumption by 25-30%. It also reduces the fossil fuel footprint by a similar amount. By eliminating the fired heater, which is the most polluting part of steam methane reforming, through electrification we are
of the electrical power that an electrolyser would consume is required. Methane consumption is reduced by about 30% compared to conventional reforming techniques. The result is low-cost, low- carbon hydrogen. Gas-fired steam methane reforming, with CO 2 emissions from the combustion heating An SMR is fed with methane from natural gas or biomethane and steam. The reaction proceeds inside an array of vertical tubes filled with a nickel- based catalyst to produce syngas, which is around 70% hydrogen and 30% carbon monoxide. To drive the reaction kinetics, heat energy must be applied at a high temperature. This is achieved by burning natural gas in the air to heat the outside of the reactor tubes. Approximately 75% of the natural gas flows through the reactor, and the balance of 25% is fired in the burners. Subsequent catalytic reactors are used to combine more steam with the carbon monoxide in the syngas to produce carbon dioxide and hydrogen. The components of this stream are then separated on a pressure swing adsorption (PSA) unit to generate pure hydrogen and ‘tail gas’. The tail gas contains carbon dioxide, unreacted methane and residual quantities of carbon monoxide, in addition to some hydrogen. These energy gases are combined with fresh methane to fire the burners. The burner flue gas is rich in carbon dioxide and can be processed using an amine wash or other suitable carbon capture system.
+ – AEC
+ – AEM
+ – PEM
+ – SOE
H (plus CO)
Air plus O
O
O
O
H
H
H
-
-
+
-
OH
OH
H
O
H O as water
H O as water
H O as water
Air
H O as water (plus CO )
Notes: 1.In the AEC, AEM and PEM, lye or water flow from the electrolyser cell with the oxygen and/or hydrogen gases. Those liquids are mixed and recirculated to the electrolyser. 2. Air is used to purge the SOE anode to avoid oxygen accumulation which may present a hazard at the high operating temperature. 3. Bipolar plates made of stainless steel (titanium for PEM) are used to stack adjacent cells in each electrolyser type. Figure 2 Electrolysers: AEC, AEM, PEM and SOE for hydrogen (and syngas) production
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