Composite Catalyst for Low-Rank Coal Depolymerization
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Solution Overview
Problem
Existing methods for increasing tar yield during coal pyrolysis, such as hydropyrolysis and use of solvents, are complex and costly, and do not effectively enhance tar production in low-rank coals.
Innovation Solution
A composite catalyst system comprising an iron salt-based catalyst and a metal salt-based catalyst, along with accelerators and surfactants, is introduced to selectively break bridge bonds in low-rank coals, allowing for higher tar yields and reduced energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional catalytic pyrolysis is used where catalyst is added on the outside surface of coal, then the process is simple, but the tar yield is low
Solution Approach 1:
The patent applies preliminary action by adding adjunct reagents to the coal structure before pyrolysis occurs. The catalyst components (iron salt-based and metal salt-based) are introduced into the coal matrix in advance, allowing them to be positioned within the coal structure where they can effectively catalyze bond breaking during pyrolysis, thereby increasing tar yield while maintaining process simplicity
Solution Approach 2:
The patent uses composite materials by combining iron salt-based catalysts with metal salt-based catalysts in a composite catalyst system. This composite approach creates synergistic effects that enhance the catalytic activity for breaking bridge bonds in coal, leading to significantly improved tar yield compared to using single catalyst systems
2Productivity
If hydropyrolysis is used to increase tar yield, then the tar production improves, but the reaction apparatus becomes complicated due to hydrogen pressurization
Solution Approach 1:
The patent extracts the hydrogen pressurization requirement from the process by using catalysts that enable effective coal depolymerization and tar formation under atmospheric or near-atmospheric pressure conditions. The iron salt-based and metal salt-based catalysts facilitate bond breaking and tar formation without requiring hydrogen gas pressurization, thereby eliminating the need for complex pressurized reaction apparatus while maintaining high tar yield
Solution Approach 2:
The patent employs catalysts that can be added in small amounts and facilitate the reaction under mild conditions, replacing the need for expensive and complex hydrogen pressurization equipment. The catalyst system enables the process to be conducted with simpler, more affordable reaction apparatus
3Productivity
If solvents like alcohols and tetrahydrofuran are used to swell LRCs, then the tar yield increases by 3.4%, but the process becomes too complicated
Solution Approach 1:
The patent replaces expensive and complex solvent-based swelling processes with a simpler catalyst addition approach. The iron salt-based and metal salt-based catalysts can be added directly to the coal without requiring large amounts of solvents like alcohols or tetrahydrofuran, thereby achieving comparable or superior tar yield with a much simpler and more cost-effective process
Solution Approach 2:
The patent changes the fundamental parameter of the process from solvent-based swelling to catalyst-based depolymerization. Instead of using solvents to alter the physical structure of the coal, the catalyst system directly promotes chemical bond breaking and tar formation, eliminating the need for complex solvent handling and recovery processes
4Productivity
If acidic ionic liquid is used to treat brown coal, then the liquid product yield increases by 75%, but the process becomes too complicated
Solution Approach 1:
The patent extracts the complexity of ionic liquid treatment by using simpler iron salt-based and metal salt-based catalysts that achieve effective coal depolymerization without requiring acidic ionic liquids. The catalyst system enables high liquid product yield through direct catalytic action on the coal structure, eliminating the need for complex ionic liquid preparation, application, and recovery processes
Solution Approach 2:
The patent employs inexpensive inorganic salt catalysts that can be added in small amounts and facilitate the depolymerization process under mild conditions, replacing the need for expensive and complex acidic ionic liquid systems. This approach achieves comparable or superior liquid product yield with much simpler and more cost-effective process equipment
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 composite catalyst significantly increases tar yield by up to 70.2% compared to methods without catalysts, while maintaining simplicity and reducing energy consumption, making it suitable for industrial application.
Implementation Method 1
a composite catalyst system comprising an iron salt-based catalyst and a metal salt-based catalyst, along with accelerators and surfactants, is introduced to selectively break bridge bonds in low-rank coals
Implementation Method 2
allowing for higher tar yields and reduced energy consumption
Data Source
AI summary
A composite catalyst for coal depolymerization, the catalyst includes an agent A and an agent B. The agent A includes an iron salt-based catalyst, and the agent B includes a metal salt-based catalyst different from the iron salt-based catalyst. The agent A and the agent B are alternately added during use.