Bio-Based LPG Heat Integration for Endothermic Reaction Heating
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Solution Overview
Problem
Conventional methods for producing liquefied petroleum gas (LPG) from bio-based sources face challenges such as high energy costs from hydrogen recycling, significant carbon dioxide waste, and inefficient conversion processes, leading to low LPG yields and loss of synthetic gas components.
Innovation Solution
A two-step process involving an exothermic oxygenate synthesis followed by an endothermic reaction, utilizing a heat transfer fluid to manage heat efficiently, and a dual-stage catalyst system to convert bio-based synthesis gas into LPG with minimal loss of H2, CO, and CO2, incorporating a heat transfer system to optimize reaction temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional recycling processes are used to recycle hydrogen from exit gas, then hydrogen recycling is achieved, but energy costs increase significantly due to recompression
Solution Approach 1:
The patent combines the exothermic oxygenate synthesis reaction with the endothermic steam reforming reaction into a single integrated reactor system. The heat generated from the exothermic reaction directly provides the energy needed for the endothermic reforming reaction, eliminating the need for separate heating systems and reducing overall energy consumption while maintaining effective hydrogen recycling
Solution Approach 2:
The patent converts the waste heat generated from the exothermic oxygenate synthesis reaction into a useful resource by using it to drive the endothermic steam reforming reaction. This transforms what would otherwise be wasted thermal energy into the driving force for producing additional synthesis gas, thereby reducing external energy requirements
2Productivity
If conventional processing is used, then carbon dioxide is produced as a byproduct, but over 10% of carbon from feedstock is wasted
Solution Approach 1:
The patent recovers and循环利用 unreacted synthesis gas components (CO, H2, CO2) from the reactor exit gas and feeds them back into the reaction system. This circular approach ensures that carbon atoms that would otherwise be lost are recovered and converted into additional LPG product, significantly reducing carbon waste while increasing overall productivity
Solution Approach 2:
The patent implements continuous recycling of unreacted synthesis gas components back into the reactor system, maintaining continuous conversion of carbon-containing gases into LPG. This continuous action ensures that carbon atoms undergo multiple conversion cycles rather than being lost in a single-pass process, thereby reducing waste and improving yield
3Use of energy by moving object
If a two-step process with heat transfer fluid is used, then heat management is optimized, but device complexity increases
Solution Approach 1:
The patent merges the heat generation function (exothermic oxygenate synthesis) and heat consumption function (endothermic steam reforming) into a single integrated reactor system with dual catalyst beds. This consolidation eliminates the need for separate heat exchangers, heat transfer fluids, and independent reactor systems, thereby reducing device complexity while maintaining optimal heat management
Solution Approach 2:
The patent uses the reaction mixture itself as the heat transfer medium between the exothermic and endothermic reaction zones within the reactor. The hot gases from the exothermic reaction directly contact and heat the feedstock entering the endothermic zone, eliminating the need for external heat transfer fluids and simplifying the overall system design
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 high LPG yields with reduced environmental impact by recycling unreacted synthesis gas components and utilizing waste heat for endothermic reactions, minimizing energy consumption and emissions.
Implementation Method 1
increasing the enthalpy of a heat transfer fluid by absorbing at least a portion of the excess heat with the heat transfer fluid
Implementation Method 2
supplying heat from the heat transfer fluid having increased enthalpy to an endothermic reaction and decreasing the enthalpy of the heat transfer fluid
Implementation Method 3
reacting a bio-based synthesis gas in an exothermic reaction and forming an LPG-enriched effluent stream, wherein the exothermic reaction generates excess heat
Implementation Method 4
supplying heat from the heat transfer fluid having increased enthalpy to an endothermic reaction
Data Source
AI summary
A method is provided for synthesizing bio-based LPG from renewable sources via a bio-based synthetic gas feedstock, including step of recovering heat from an oxygenate conversion zone and forming a heat transfer fluid with increased enthalpy, wherein the heat transfer fluid is used to provide heat for an endothermic reaction zone, and this improves the energy efficiency of the process, reduces or eliminates the need for fired furnaces, and reduces CO2 emissions from fired furnaces.