Hydrodeoxygenation Reactor System with Phase Separation
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Solution Overview
Problem
Current hydrodeoxygenation processes face challenges in efficiently converting oxygenates due to low reactivity of certain oxygenates, leading to side reactions and catalyst damage, and result in unreacted oxygenates being discarded or requiring energy-intensive separation, especially in aqueous phases.
Innovation Solution
A system and process that includes a reactor with a hydrodeoxygenation catalyst, phase separation, mixing with a water-insoluble solvent to extract unreacted oxygenates, and recycling them back into the process, along with hydrogen recovery and solvent reuse, to enhance oxygenate conversion without increasing process severity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the severity of the HDO process is increased (temperature, residence time, hydrogen partial pressure) to convert refractory oxygenates, then oxygenate conversion is improved, but side reactions (cracking to lights and coking) increase and catalyst lifespan decreases
Solution Approach 1:
The HDO process is divided into two separate stages: a first HDO reactor for initial conversion and a second HDO reactor for polishing unreacted oxygenates. This segmentation allows each reactor to operate at optimized conditions - the first at moderate severity to avoid excessive side reactions, and the second at higher severity specifically for refractory oxygenates, thereby resolving the contradiction between conversion and harmful side reactions
Solution Approach 2:
A phase separator is introduced as an intermediary between the two HDO reactors. It separates the aqueous phase containing unreacted oxygenates from the hydrocarbon phase, and only the aqueous phase is fed to the second HDO reactor. This intermediary mechanism ensures that the second reactor processes a targeted stream with high oxygenate concentration, improving conversion efficiency while controlling side reactions through precise process design
2Productivity
If additional HDO is applied to the aqueous portion containing unreacted oxygenates, then oxygenate conversion is improved, but energy consumption increases and catalyst damage occurs due to elevated water content
Solution Approach 1:
The phase separator extracts and removes the bulk of the aqueous phase containing unreacted oxygenates from the first HDO product stream. By taking out this specific fraction for further processing in the second HDO reactor, the system avoids the energy-intensive treatment of large volumes of water while still achieving high oxygenate conversion through targeted processing of the oxygenate-rich aqueous phase
3Productivity
If additional HDO is applied to the aqueous HDO product, then oxygenate conversion is improved, but the required size and cost of the second HDO reactor increases due to elevated water content
Solution Approach 1:
The phase separator acts as an intermediary that pre-concentrates unreacted oxygenates by separating them into the aqueous phase. This intermediary step reduces the water content in the feed to the second HDO reactor, allowing for a smaller and more cost-effective reactor design while still achieving the desired oxygenate conversion levels
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 increases oxygenate conversion to liquid hydrocarbon fuels while avoiding side reactions and catalyst degradation, and allows for efficient recycling and reuse of unreacted oxygenates and hydrogen, improving overall yield and catalyst lifespan.
Implementation Method 1
Chemically, hydrodeoxygenation removes oxygen from the feedstock molecules in the presence of gaseous hydrogen and a HDO catalyst, and rejects it in the form of water
Implementation Method 2
a first separator operable to receive the partially-deoxygenated product and phase-separate the partially-deoxygenated product into an aqueous phase comprising unreacted oxygenates, a non-aqueous phase comprising hydrocarbons, and light gases comprising hydrogen
Implementation Method 3
a mixer configured to receive the aqueous phase and to mix the aqueous phase with a solvent that is immiscible with water to produce an emulsion, wherein the solvent is capable of dissolving unreacted oxygenates
Implementation Method 4
a distillation apparatus configured to receive the solvent comprising unreacted oxygenates and to produce a separated solvent and separated unreacted oxygenates
Data Source
AI summary
The present disclosure relates generally to processes and systems for the hydrodeoxygenation of an oxygenate feedstock that increases the conversion of oxygenates to hydrocarbons while avoiding detrimental effects resulting from increasing the severity of the hydrodeoxygenation reaction.