Pyrolysis Carbon Upgrading Through Slurry Hydroprocessing
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Solution Overview
Problem
Conventional hydrogen production methods using pyrolysis of methane generate solid carbon as a byproduct, which lacks a viable disposal method that does not contribute to CO2 emissions, and existing technologies do not effectively upgrade this carbon into higher value products.
Innovation Solution
A method involving the combination of pyrolysis carbon with a solvent to form a slurry, followed by exposure to hydrogen and catalysts under specific conditions, or with quaternary bases and metal halides, to increase the atomic hydrogen-to-carbon ratio, converting the pyrolysis carbon into higher value products such as carbon fiber and structural materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If methane pyrolysis is used to produce hydrogen, then CO2 emissions are avoided, but solid carbon byproduct requires disposal that may lead to CO2 emissions
Solution Approach 1:
The patent converts the harmful solid carbon byproduct into a valuable upgraded carbon product through hydroprocessing and alkylation reactions. The carbon that would otherwise require disposal or combustion (causing CO2 emissions) is transformed into high-value materials such as carbon fiber precursors and structural carbon products, thereby eliminating the harmful effect while creating economic benefit.
Solution Approach 2:
The patent changes the chemical parameters of the solid carbon byproduct through controlled hydroprocessing conditions (temperature, pressure, hydrogen partial pressure, catalyst composition) and subsequent alkylation reactions. These parameter changes transform the carbon from a low-value byproduct with high disposal cost into a high-value upgraded carbon product with improved properties and multiple potential applications.
2Quantity of substance
If pyrolysis carbon is upgraded through hydroprocessing and alkylation, then higher value products are obtained, but process complexity increases
Solution Approach 1:
The patent segments the upgrading process into two distinct stages: (1) hydroprocessing of pyrolysis carbon under controlled conditions to produce intermediate upgraded carbon, and (2) alkylation reactions to further enhance the carbon product value. This segmentation allows each stage to be optimized independently and facilitates easier process control and management compared to a single complex step.
Solution Approach 2:
The patent uses an intermediary upgraded carbon product between the initial pyrolysis carbon and the final high-value carbon product. This intermediary stage allows for gradual transformation and quality improvement, making the overall process more manageable and enabling intermediate product utilization if needed.
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 method effectively upgrades pyrolysis carbon to a higher hydrogen content, facilitating the conversion into resin-like materials and structural products, reducing the need for additional CO2 emissions and providing a valuable alternative to fuel disposal.
Implementation Method 1
exposing the particles of pyrolysis carbon to hydrogen in the presence of a catalyst under slurry hydroprocessing conditions
Implementation Method 2
exposing the particles of pyrolysis carbon to hydrogen in the presence of a catalyst under slurry hydroprocessing conditions to form an upgraded carbon product comprising an atomic ratio of hydrogen to carbon of 0.25 or more
Implementation Method 3
exposing at least a portion of the upgraded carbon product to a) a quaternary base and optionally at least one of a metal hydroxide and a metal alkoxide under phase transfer catalysis conditions, b) an alkyl halide and a metal halide at a temperature of 20° C. to 200° C. and a pressure of 100 kPa-a to 5.0 MPa-a
Implementation Method 4
combining particles of pyrolysis carbon with a solvent to form a slurry
Data Source
AI summary
Methods are provided for upgrading of pyrolysis carbon in order to allow for conversion of the pyrolysis carbon into higher value products. Instead of attempting to convert methane into a high value carbon product (such as carbon nanotubes) and H2 in a single reaction step, pyrolysis conditions can be used to form H2 and pyrolysis carbon. The pyrolysis carbon can then be treated in order to convert the pyrolysis carbon (H to C atomic ratio of less than 0.20) into a product with a higher hydrogen content (H to C atomic ratio of 0.25-0.9 or 2.0-7.0 wt % H). The treatment can correspond to exposing the pyrolysis carbon with hydrogen in the presence of a catalyst, exposing the pyrolysis carbon to conditions for alkylation, or a sequential combination thereof. This can convert the pyrolysis carbon into heavy hydrocarbon products that are resin-like solids at room temperature.