TDA Research Inc. is developing a new technology that will allow hydrogen to be produced in refineries at a cost that is considerably lower than hydrogen produced from conventional technologies or purchasing hydrogen from a third party. This technology converts “bottom of the barrel” residuum into hydrogen. In TDA’s process, residuum is steam reformed over nickel based catalysts to produce hydrogen without catalyst deactivation and without the need for an oxygen plant; this greatly expands the range of feedstocks that can be used to generate hydrogen. We can steam reform residuum over nickel based catalysts without catalyst deactivation because the system uses a fluidized bed with periodic catalyst regeneration with air. The process is essentially chemical looping steam reforming. Residuum and steam are fed into a fluidized bed reactor containing Ni steam reforming catalyst at 870°C to generate syngas (CO + H2). Because the process uses contact times on the order of minutes, not enough carbon builds up on the catalyst to cause irreversible deactivation. The catalyst is then regenerated by burning the coke with air. In the laboratory, this is done using a single reactor with a nitrogen purge between reforming and regeneration steps; however, in an industrial setting, a circulating fluidized bed system would be used that would be somewhat similar to the early ESSO catalytic cracking reactors. Burning off the coke in the regenerator reheats the catalyst to about 900°C for the next reforming step (a small amount of residuum, heavy oil or other fuel can be added to the regenerator to increase the temperature if there is not enough coke on the catalyst). The hot nickel catalyst returning to the reforming reactor is present as NiO but is quickly reduced to active nickel metal by the hydrocarbons in the feed.
TDA has conducted an extensive series of tests with atmospheric tower bottoms (ATB) and two types of vacuum tower bottoms (VTB). Both VTB samples were solids at room temperature and were heated to be able to feed them into the laboratory reactor. With ATB, it was possible to operate with steam to carbon (s/c) ratios as low as 5. VTB required somewhat higher steam/carbon ratios (6-8). No catalyst deactivation has been observed with ATB or the lighter of the two VTB samples in that no change in product selectivity or yield was observed over 100+ cycles. We are currently investigating other catalysts and a very heavy VTB as well as conducting long term testing (hundreds of cycles).
Would you like to access this content?
No problem. You just have to complete the following steps.
You have completed 0 of 2 steps.
You must be logged in to view this content. Log in now.
Purchase Technical Presentation
You must purchase this technical presentation using one of the options below.
If you already purchased this content recently, please click here to refresh the system's record of ownerships.
|Credits||0.5 Use credits|
|List Price||$25.00 Buy now|
|AIChE Members||$15.00 Buy now|
|AIChE Fuels and Petrochemicals Division Members||Free Free access|
|AIChE Undergraduate Student Members||Free Free access|
|AIChE Graduate Student Members||Free Free access|