Circulating Fluidized Bed Steam Reforming for Heavy Oil Hydrogen
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Solution Overview
Problem
Current steam reforming processes are limited in their ability to efficiently produce hydrogen from heavy oil feedstocks due to issues such as irreversible catalyst deactivation, coke formation, and sulfur poisoning, and are often capital intensive, especially when using high-temperature gasification methods.
Innovation Solution
A circulating fluidized bed process using a nickel-based catalyst mixed with alpha-alumina as a solid diluent, which allows for continuous hydrogen production without catalyst deactivation, by regenerating the catalyst with air and avoiding the introduction of nitrogen into the syngas, thus enabling the use of heavy oil feedstocks like atmospheric and vacuum tower bottoms, and pyrolysis oil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional steam reforming is used with heavy oil feedstocks, then hydrogen production is achieved, but catalyst deactivation and coke formation occur
Solution Approach 1:
The catalyst is periodically regenerated by switching between reforming mode (producing hydrogen) and regeneration mode (burning off coke deposits). This periodic switching allows the catalyst to maintain activity over extended periods by removing accumulated carbon deposits before they cause permanent deactivation
Solution Approach 2:
The process changes operational parameters between two distinct modes: reforming conditions (lower temperature, hydrogen-producing reactions) and regeneration conditions (higher temperature, air-introduced combustion). This parameter switching enables the catalyst to function productively then be restored without permanent deactivation
2Productivity
If high-temperature gasification is used to produce hydrogen from heavy oil, then hydrogen production capability is improved, but capital costs increase
Solution Approach 1:
The process operates at moderate temperatures during the reforming phase rather than requiring the extremely high temperatures of conventional gasification. This parameter change enables heavy oil conversion at lower capital investment while maintaining productive hydrogen generation
Solution Approach 2:
The system uses its own produced hydrogen as the reducing agent to convert metal oxides back to active catalyst form during regeneration. This self-service mechanism eliminates the need for external reducing agents and simplifies the overall process configuration
3Object-generated harmful factors
If air is introduced for catalyst regeneration, then coke removal is achieved, but nitrogen dilutes the syngas
Solution Approach 1:
The regeneration function is extracted from the main reforming reactor and performed in a separate regeneration reactor. This separation allows air to be introduced for coke combustion without contaminating the hydrogen-rich syngas stream produced in the reforming reactor
Solution Approach 2:
The catalytic system is segmented into two distinct functional reactors: one dedicated to reforming (hydrogen production) and another to regeneration (coke removal). This segmentation enables independent optimization of each function without compromising the other
4Productivity
If heavy oil feedstocks are processed by conventional methods, then hydrogen is produced, but sulfur poisoning occurs
Solution Approach 1:
The periodic regeneration cycle includes high-temperature air treatment that oxidizes and removes sulfur deposits accumulated during reforming. This periodic cleaning action prevents progressive sulfur poisoning and maintains catalyst activity when processing sulfur-containing heavy oils
Solution Approach 2:
The sulfur that accumulates on the catalyst during reforming is converted into a removable form through oxidative regeneration. The harmful sulfur deposits are transformed into sulfur oxides that can be gasified and removed, converting a deactivating contaminant into a manageable byproduct
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process achieves low-cost, continuous hydrogen production with high purity, expanding the range of feedstocks that can be used and reducing capital and operating costs compared to conventional methods, while maintaining catalyst activity and avoiding nitrogen dilution in the syngas.
Implementation Method 1
A circulating fluidized bed process using a nickel-based catalyst mixed with alpha-alumina as a solid diluent
Implementation Method 2
A circulating fluidized bed process using a nickel-based catalyst mixed with alpha-alumina as a solid diluent
Implementation Method 3
by regenerating the catalyst with air
Implementation Method 4
CH4+2H2O→CO2+4H2
Implementation Method 5
This process achieves low-cost, continuous hydrogen production with high purity
Data Source
AI summary
The present invention provides a steam reforming process for heavy oil or hydrocarbons using a circulating fluidized bed reactor, the process having a reforming step and a regeneration step, wherein the reforming step and the regeneration step comprise a fluidized reactor containing a fluidizable nickel-containing reforming catalyst and produce hydrogen as a product of the reforming bed. The invention produces high purity hydrogen in the synthesis gas product stream and avoids irreversible fouling on the catalyst.