Hydrogen Generation Process

Within the HyRadix® Aptus™ and Adéo™ systems, four major process steps are undertaken to generate high-purity hydrogen. The steps in this process are outlined in the diagram below:

Step #1: Sulfur Removal

The natural gas (NG) or LPG feed first passes through an ambient temperature sulfur adsorption vessel. The proprietary adsorbent in this vessel has been specifically designed to remove sulfur species native to NG or LPG feeds as well as those sulfur compounds that are added as odorants for leak detection. The sulfur adsorbent has been proven effective in removing compounds ranging from H₂S and mercaptans to thiophenes such as THT. Since sulfur is known to affect the performance of all reforming catalysts, removing the sulfur prior to entering the reforming section ensures the highest level of reforming catalyst performance and maximum catalyst life.

Step #2: Reforming

During the reforming step, the NG or LPG feed is converted into a hydrogen rich product stream. At the entrance of the reforming catalyst bed, the feed, air and steam are mixed in proportions that are chosen to maximize hydrogen production from the given feedstock. The conversion takes place over a bi-functional catalyst that promotes both partial oxidation and steam reforming reactions in the same catalyst bed. This results in a direct transfer of heat within the catalyst bed and efficient production of hydrogen. The direct transfer of heat also means the process is responsive to changes in hydrogen demand requirements.

Step #3: Hydrogen Purification

Hydrogen purification is performed via the use of Pressure Swing Adsorption (PSA) technology. The PSA technology employed by HyRadix combines novel process hardware technology with proprietary adsorbents to attain a very high recovery of the product hydrogen. In addition, the process ensures removal of all of impurities such as water, CO, CO₂, and CH₄, which are harmful to end user industrial and fuel cell applications. This unique combination of technologies allows for a wide range of hydrogen purity control with the only product impurities being the inert components nitrogen and argon.

Step # 4: Heat Integration

The heat integration step is key to achieving overall process efficiency. Heat is recovered from high temperature streams, such as the reactor section effluent or the PSA waste gas stream, and is used to preheat the feed streams to the reactor and generate steam for the reforming reaction. Additionally, any CO that remains in the PSA waste gas stream is converted to CO₂ before the waste gas stream exits the unit.