Group VI Metal Catalyst Deoxygenation for Biocomponent Coprocessing
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Solution Overview
Problem
The processing of biocomponent feeds in refineries is hindered by high oxygen content, leading to catalyst poisoning, corrosion, and temperature control issues due to the production of CO and CO2, as well as hydrogen consumption, which limits refinery operations.
Innovation Solution
A method involving a supported Group VI metal catalyst, such as tungsten or physically promoted molybdenum, is used for initial deoxygenation of a feedstock containing both mineral and biocomponent fractions under low pressure conditions, followed by hydrotreatment to reduce sulfur and nitrogen content, thereby managing temperature and minimizing hydrogen usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional hydroprocessing methods are used to remove oxygen from biologically-derived feedstocks, then oxygen content is reduced, but catalyst poisoning and contaminant build-up occur
Solution Approach 1:
The hydroprocessing operation is divided into two separate sequential operations: first deoxygenation to remove oxygen from the biologically-derived feedstock, then hydroprocessing to remove sulfur and nitrogen. This segmentation prevents the catalyst used in each step from being poisoned by contaminants present in the original feedstock, as each catalyst is exposed only to the feedstock after the previous contaminants have been removed.
2Quantity of substance
If deoxygenation is performed to remove oxygen from feedstock, then oxygen content decreases, but temperature control difficulties arise due to exothermic reactions
Solution Approach 1:
The exothermic deoxygenation reaction is separated from the hydroprocessing operation into a distinct first step. This allows the heat of reaction to be managed independently in the deoxygenation stage, preventing temperature control issues that would occur if oxygen removal and hydroprocessing were performed simultaneously in a single reactor.
3Quantity of substance
If deoxygenation is performed to remove oxygen from feedstock, then oxygen content decreases, but hydrogen consumption increases
Solution Approach 1:
By separating deoxygenation from hydroprocessing into two sequential steps, the process optimizes hydrogen usage. The deoxygenation step removes oxygen first, and the subsequent hydroprocessing step then removes sulfur and nitrogen with reduced hydrogen consumption compared to performing all removals simultaneously, as the catalyst in the second step is not poisoned by oxygen-containing compounds.
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 approach effectively reduces oxygen content, prevents catalyst deactivation, and optimizes hydrogen use, enabling the production of fuels with low sulfur and nitrogen levels while maintaining reactor temperature stability.
Implementation Method 1
exposing a feedstock containing a mineral fraction and a biocomponent fraction to a supported Group VI metal catalyst in the presence of hydrogen under effective deoxygenation conditions
Implementation Method 2
exposing a feedstock containing a mineral fraction and a biocomponent fraction to a supported Group VI metal catalyst in the presence of hydrogen under effective deoxygenation conditions
Implementation Method 3
exposing the deoxygenated feed to a hydroprocessing catalyst under effective hydroprocessing conditions to produce an effluent having a sulfur content of about 100 wppm or less
Data Source
AI summary
Feedstocks containing biocomponent materials are coprocessed with mineral feeds using a Group VI metal catalyst prior to hydrodesulfurization of the feedstocks. The Group VI metal catalyst is optionally a physically promoted Group VI metal catalyst.