ATR process

H2 production from ethanol (as well as methanol) employs these methodologies either as such or after slight modifications, especially in the ATR process, wherein a separate combustion zone is usually not present (Scheme 3). A mixture of ethanol, steam and 02 with an appropriate ethanol steam 02 ratio directly enters on the catalyst bed to produce syngas at higher temperature, around 700 °C.18,22 The authors of this review believe that under the experimental conditions employed, both steam reforming and partial oxidation could occur on the same catalyst surface exchanging heats between them to produce H2 and carbon oxides. The amount of 02 may be different from what is required to achieve the thermally neutral operation. Consequently the reaction has been referred to as an oxidative steam reforming... 

In ATR process, the feedstock is reacted predominantly with oxygen by the use of a burner and a fixed catalyst bed is used for attaining reaction equilibrium. 

ATR is a stand-alone process which combines POX and SR in a single reactor. The ATR process was first developed in the late 1950s by Topsoe, mainly for industrial synthesis gas production in ammonia and methanol plants [27]. 

The industrial processes for hydrogen production are well established [9, 30, 31], but may not be appropriate for small-scale stationary applications such as residential fuel cells or for unattended operation such as on-site hydrogen generation. These new applications allow for new process designs based on catalyst and engineering improvements [10, 32]. Hence a study of the ATR process has to involve both chemical and engineering aspects. 

ATR reformer temperatures are in the range of 900-1150 °C, and the reformers with pressure between 1 and 80 bar have been designed and built so far. The ATR reactor is more compact than a steam reformer but larger than a POX unit. The main advantage of the ATR process is that it will produce a syngas with very favorable H2-to-CO ratio for downstream usage in chemical synthesis. The ratio should be 2 for Fischer-Tropsch liquids or methanol synthesis. 

A simplified flow diagram of ATR process is shown in Figure 8 [14]. Preheated hydrocarbon feed and oxygen mixed with a small amount of steam enter the top of the reformer reactor. Partial combustion takes place in the... 

ATR) process. The type and number of affordable downstream units also determine the reformer characteristics. For example, if the fuel is methanol, then a high-temperature water-gas shift reactor is not required, given that CO levels in the reformate do not significantly exceed 1%. High-temperature FCs (new generation of HT PEMFC, MOFC or MCFC) are more tolerant towards CO and the number of clean-up units in the reformer can be reduced. 

Combined Autothermal Reforming. In the combined autothermal reforming (CAR) process developed by Uhde (27), the HSR process and the ATR process are combinedin to one reactor (Fig. 3). 

The autothermal reforming (ATR) process is a hybrid of partial oxidation and steam reforming using a burner and a fixed catalyst bed for... 

As shown in Table 1.8, the ATR process at low steam carbon ratio is very close to fulfilling H2/CO=2 at selectivities above 90% for CO H2. 

Because CPO is an exothermic process, and SR is an endothermic process, these two can be combined in the autothermal reforming (ATR) process. The overall reaction of an autothermal process for methane, with the shift reaction included, is... 

In simplistic terms, the SR process generally provides the highest hydrogen yield and consequently the highest efficiency. Because of the endothermic reaction, its thermal management tends to be the most complex and bulky. Conversely, POX is typically the least efficient but has the simplest configurations. The ATR process tends to be intermediate to the other two in both respects. 

Figure 9.2 (a) Attenuated total reflection image of a fingerprint through a glass of water with visible light and (b) ATR process for infrared spectroscopy. 

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