Chemical Looping Deoxygenation Catalyst for Bio-oil
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Solution Overview
Problem
Bio-oil produced from pyrolysis of biomass has high oxygen content, leading to low heating value and unfavorable carbon to oxygen and hydrogen to carbon ratios, making it difficult to process into useful products.
Innovation Solution
A chemical looping deoxygenation catalyst system using metal sulfides or layered double hydroxides that oxidize and reduce to remove oxygenates as carbon oxides, improving the fuel's quality by reducing oxygen content and increasing hydrogen to carbon ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pyrolysis is performed at moderate temperatures (400-500°C) to produce bio-oil, then bio-oil yield is maximized, but the oxygen content becomes too high resulting in low heating value and unfavorable carbon to oxygen ratio
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of bio-oil through catalytic deoxygenation. The catalyst system changes the oxygen content parameter from high (30-40 wt%) to low (<10 wt%), thereby transforming the heating value parameter from low to high, while maintaining the bio-oil yield achieved at moderate pyrolysis temperatures.
Solution Approach 2:
The patent introduces a catalyst system as an intermediary substance to mediate the deoxygenation process. The catalyst (metal sulfides or layered double hydroxides) acts as a mediator that facilitates the removal of oxygenates from bio-oil through chemical reactions, enabling the transformation from low-quality to high-quality fuel without directly altering the pyrolysis conditions.
2Quantity of substance
If deoxygenation is achieved through dehydration reactions, then oxygen is removed in the form of water, but hydrogen contributing to higher heating value is sacrificed
Solution Approach 1:
The patent applies the extraction principle by selectively removing oxygenates from bio-oil through catalytic decomposition reactions. The catalyst system extracts oxygen in the form of carbon oxides (CO and CO2) through decarbonylation and decarboxylation reactions, separating the harmful oxygen component while preserving the hydrogen and carbon backbone that contribute to heating value.
Solution Approach 2:
The patent changes the reaction pathway parameter from dehydration to decarbonylation/decarboxylation. This parameter change in the deoxygenation mechanism allows oxygen to be removed as carbon oxides rather than water, thereby preserving hydrogen content and maintaining higher heating value while achieving the same oxygen removal objective.
3Adaptability or versatility
If high oxygen content is present in pyrolysis oil, then the oil is more polar and readily soluble with water, but chemical stability decreases and processing difficulty increases
Solution Approach 1:
The patent applies parameter changes by transforming the chemical composition parameters of pyrolysis oil. The catalyst system changes the oxygen content parameter and the polarity parameter simultaneously, converting high-polarity, water-soluble oxygenates into low-polarity, water-insoluble hydrocarbons. This parameter transformation improves chemical stability while reducing water solubility, making the fuel more suitable for practical applications.
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
The catalyst system effectively reduces oxygen content in bio-oil, enhancing its heating value and quality by increasing the hydrogen to carbon ratio, making it more suitable for further processing and use as a high-quality pyrolysis oil.
Implementation Method 1
metal sulfide, to produce metal sulfate by oxidising the sulfide to a sulfate while reducing the oxygen content of the bio-oil
Implementation Method 2
oxidising the sulfide to a sulfate
Implementation Method 3
reducing the oxygen content of the bio-oil
Implementation Method 4
Decoxygenation occurs through the removal of oxygen in the form of either water (dehydration) or carbon oxides (decarboxylation and decarbonylation)
Implementation Method 5
layered double hydroxides (LDH) and its derivatives are used to decarboxylate crude bio-oil
Data Source
AI summary
The invention provides a catalyst system and method for the deoxygenation of hydrocarbons, such as bio-oil, using a sulphide-sulfate or an oxide-carbonate (LDH) system. The invention extends to a pyrolysis process of a carbonaceous bio-mass wherein a first combustion zone is carried out in one or more combustion fluidised beds in which a particulate material including chemically looping deoxygenation catalyst particles is fluidised and heated, and a second pyrolysis zone carried out in one or more pyrolysis fluidised beds in which the hot particles, including the catalyst particles, heated in the combustion zone are used for pyrolysis of the bio-mass, said combustion zone being operated at a temperature of from 250° C. to 1100° C., typically around 900° C., and the pyrolysis zone being operated at a temperature of from 250° C. to 900° C., typically 450° C. to 600° C., said catalyst particles being oxygenated in the pyrolysis zone in the presence of oxygenates in the pyrolysis oil and regenerated in the combustion zone either by calcining to drive off the carbon oxides, such as CO2, or by reduction to its form which is active for deoxygenation of the pyrolysis oil.