Hydrogen separation autothermal reforming

Today, different processes (steam reforming, autothermal reforming, partial oxidation, gasification) are available and commercially mature for hydrogen production from natural gas or coal. These processes would have to be combined with technologies for C02 capture and storage (CCS), to keep the emissions profile low. A power plant that combines electricity and hydrogen production can be more efficient than retrofitted C02 separation systems for conventional power plants. 

Long-term (>1000 h) tests were performed in a separate reactor equipped with a sohd-state on-line hydrogen sensor and infrared carbon monoxide and carbon dioxide detectors. Batch sampling was performed at the exit stream. This system allowed us to determine the durabihty of the autothermal reforming catalyst and to determine if there are any long-term problems (poisoning, coking) caused by the fuel components. 

A possible approach Natural gas can be converted at a high temperature into hydrogen, CO, C02 (syngas) in a steam reformer or partial-oxidation reactor, or autothermal reformer which is a combination of the first two. Most of the CO in the syngas is typically converted into carbon dioxide at a lower temperature in a water-gas shift reactor. The remaining small amount of CO must be removed to below 10 ppm level. This can be done using adsorption, or membrane separation, or catalytic preferential oxidation (at about 90°C with an air stream), or other practical means. Also, there are designs with membrane reformers in the literature. 

Few studies are reported in literature dealing with the integration of an autothermal reforming reactor with a membrane for hydrogen separation, and most of them are simulation studies. 

Tosti et al., (2010) performed a two-step process for autothermal ethanol reforming. A first reformer consists of a fixed-bed reactor where P1/AI2O3 catalysts were used. The reactor operates at 700—740 °C and water/ethanol mixture was fed in a molar ratio of 2.5. As is shown in Figure 3.4 water/ethanol and oxygen were premixed before the reactor. The produced syngas was introduced in a second reformer where WGS reaction occurs, CO was completely converted into CO2 at 350—380 °C, and at the same time hydrogen is separated by a multitubular Pd/Ag module. 

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