Combination of autothermal reforming with water-gas-shift reaction - small-scale testing of different water-gas-shift catalysts

The amount of carbon monoxide in the reformate of the autothermal reforming (ATR) of liquid hydrocarbons can be significantly reduced by means of the water-gas-shift (WGS) reaction. It is possible to directly feed the reformate from the ATR of liquid hydrocarbons to the WGS reactor without deactivation of the WGS catalyst. In a first step, the dry reformate from the ATR and a separately fed stream of steam were used to conduct the WGS reaction. Special emphasis was given to the chemical composition of the reformate which under convenient reaction conditions did not feature any detrimental higher aliphatic or aromatic hydrocarbons. Applying these premises, no catalyst deactivation could be observed. Strong differences concerning the catalytic activity between the three investigated commercial monolithic catalysts could be observed. The most active one showed a very promising catalytic behaviour. At a gas hourly space velocity (GHSV) of 12,250h(-1), CO conversion amounted to 85% at 280degreesC. This result reduces the CO concentration in the reformate from 6.1 to about 0.9 vol.%. In a second step, also the non-converted water from the ATR was fed to the reactor for the WGS reaction together with the additional components of the reformate. In this case, also the amount of total carbon dissolved in the water was analysed, which might - after adsorption - have a deleterious effect on the accessibility of the active sites of the WGS catalyst. No catalyst deactivation was observed within almost 90 h under ATR conditions generating only traces of carbon dissolved in the water. (C) 2003 Elsevier B.V. All rights reserved.