Biomass Hydropyrolysis to Biofuel via Three-Stage Conversion
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Solution Overview
Problem
Hydropyrolysis-based processes for producing liquid hydrocarbons from biomass often fail to meet specifications for diesel and gasoline due to undesirable hydrocarbon molecule distributions, leading to poor octane and cetane numbers, necessitating flexibility in processing to meet varying end-product demands and improve product quality.
Innovation Solution
A three-stage process involving hydropyrolysis, hydroconversion, and hydroprocessing, with the addition of aliphatic or aromatic hydrocarbon precursors in the third stage, to enhance product properties such as cetane and octane numbers, and allow for tailored product slates and hydrogen production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single-stage hydropyrolysis process is used to produce liquid hydrocarbons from biomass, then the process is simple and fast, but the hydrocarbon product has undesirable molecule distribution resulting in poor octane and cetane numbers
Solution Approach 1:
The single-stage hydropyrolysis process is divided into three sequential stages: (1) fast pyrolysis to produce vapors, (2) catalytic cracking to break down large molecules into desirable hydrocarbon ranges, and (3) hydroprocessing to adjust molecule distribution and improve octane/cetane numbers. This segmentation allows each stage to optimize for its specific function, achieving both high productivity and precise product quality control.
Solution Approach 2:
Catalysts are introduced as intermediary substances in stages 2 and 3 to mediate the transformation of pyrolysis vapors into high-quality hydrocarbons. The catalysts facilitate controlled cracking and hydroprocessing reactions that would otherwise require extreme conditions, enabling precise control over product composition while maintaining process efficiency.
2Quantity of substance
If the hydropyrolysis process produces hydrocarbon liquid products, then fuel supply is achieved, but the products do not fulfill specifications for diesel and gasoline in many locations due to poor molecule distribution
Solution Approach 1:
The process applies different processing conditions and catalysts to different portions of the hydrocarbon mixture. The catalytic cracking stage targets specific molecular weight ranges for diesel and gasoline production, while the hydroprocessing stage locally adjusts the composition to meet specific octane and cetane number requirements. This local quality control ensures that each product fraction meets its specific specification requirements.
Solution Approach 2:
The process dynamically adjusts operating parameters including temperature, pressure, and catalyst composition across the three stages to optimize product specifications. By changing these parameters sequentially through the processing stages, the system can produce hydrocarbon liquids that comply with various regional diesel and gasoline specifications while maintaining high production volumes.
3Manufacturing precision
If flexible processing options are added to adjust hydrocarbon product fractions, then product quality and specifications can be met, but the device complexity increases
Solution Approach 1:
The three processing stages are combined into an integrated flow system where the output of one stage directly feeds the next. The pyrolysis reactor, catalytic cracking reactor, and hydroprocessing reactor are connected in sequence with integrated heat and mass transfer systems. This merging reduces the complexity that would result from separate independent processing units while maintaining the flexibility to adjust product quality through stage-specific parameter control.
Solution Approach 2:
The catalytic cracking and hydroprocessing stages serve multiple functions: they simultaneously crack large molecules, adjust hydrocarbon distribution, remove oxygenates, and tune octane/cetane numbers. This multi-functionality reduces the need for additional separate processing units, thereby limiting the increase in device complexity while achieving comprehensive product quality control.
4Manufacturing precision
If downstream hydroprocessing is implemented to upgrade hydrocarbon products, then fuel specifications can be met, but the process requires additional reactors and catalysts increasing complexity
Solution Approach 1:
The pyrolysis stage performs preliminary decomposition of biomass into volatile components before the hydrocarbon products require final specification adjustment. This preliminary action simplifies the subsequent hydroprocessing requirements, as the feed to the hydroprocessing reactor is already partially converted, reducing the severity and complexity of the final upgrading step compared to processing raw biomass directly.
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 process achieves improved yields and quality of hydrocarbon products, meeting specific fuel specifications by upgrading biomass-derived feedstocks and utilizing locally available materials, while reducing oxygen, sulfur, and nitrogen content, thus enhancing process economics and sustainability.
Implementation Method 1
a first stage of hydropyrolysing the solid feedstock in a hydropyrolysis reactor vessel in the presence of molecular hydrogen and one or more deoxygenation catalysts
Implementation Method 2
in the presence of molecular hydrogen and one or more deoxygenation catalysts
Implementation Method 3
a second stage of hydroconverting the partially deoxygenated hydropyrolysis product in a hydroconversion reactor vessel in the presence of one or more hydroconversion catalysts and of the H2O, CO2, CO, H2, and C1-C3 gases
Implementation Method 4
condensing the vapour phase product of step c) to provide a liquid phase product comprising substantially fully deoxygenated C4+ hydrocarbon liquid
Implementation Method 5
combining an aliphatic hydrocarbon precursor or an aromatic hydrocarbon precursor with at least a portion of the substantially fully deoxygenated C4+ hydrocarbon liquid and co-processing the resultant liquid in a hydroprocessing reactor vessel in the presence of hydrogen and one or more hydroprocessing catalysts
Data Source
AI summary
The present invention provides a process for producing liquid hydrocarbon products from solid biomass and/or residual waste feedstocks, said process comprising the steps of: a) a first stage of hydropyrolysing the solid feedstock in a hydropyrolysis reactor vessel in the presence of molecular hydrogen and one or more deoxygenation catalysts, producing a product stream comprising partially deoxygenated hydropyrolysis product, H2O, H2, CO2, CO, C1-C3 gases, char and catalyst fines; b) removing said char and catalyst fines from said product stream; c) a second stage of hydroconverting said partially deoxygenated hydropyrolysis product in a hydroconversion reactor vessel in the presence of one or more hydroconversion catalysts and of the H2O, CO2, CO, H2, and C1-C3 gas generated in step a), producing a vapour phase product comprising substantially fully deoxygenated hydrocarbon product, H2O, CO, CO2, and C1-C3 gases; d) condensing the vapour phase product of step d) to provide a liquid phase product comprising substantially fully deoxygenated C4+ hydrocarbon liquid and aqueous material and separating said liquid phase product from a gas phase product comprising H2, CO, CO2, and C1-C3 gases; e) removing the aqueous material from the substantially fully deoxygenated C4+ hydrocarbon liquid; and f) a third stage comprising combining an aliphatic hydrocarbon precursor or an aromatic hydrocarbon precursor with at least a portion of the substantially fully deoxygenated C4+ hydrocarbon liquid and co-processing the resultant liquid in a hydroprocessing reactor vessel in the presence of hydrogen and one or more hydroprocessing catalysts.