LPG Hydrocarbon Production Using Interstage Water and Heat Removal
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Solution Overview
Problem
Existing processes for converting synthesis gas to liquefied petroleum gas (LPG) hydrocarbons, such as propane and butane, face challenges in reaction product selectivity, yield, catalyst stability, and temperature control, which affect commercial viability, particularly when using renewable resources like biogas or biomass.
Innovation Solution
The strategic removal of water and/or heat from the LPG synthesis process, including between reactors or downstream, enhances catalyst stability and selectivity by mitigating non-selective conversions and reducing exothermic reactions, allowing for the use of various reactor types like fluidized or fixed bed reactors without continuous catalyst regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water and heat are removed from the LPG synthesis process, then catalyst stability and selectivity are improved, but process complexity and equipment requirements increase
Solution Approach 1:
The synthesis process is divided into multiple stages with interstage cooling and water removal. This segmentation allows heat and water to be removed at specific points between reactors, improving catalyst stability in each stage while managing the overall process complexity through modular design.
Solution Approach 2:
Water and heat are removed preliminarily between reaction stages before the catalyst is exposed to conditions that would cause deactivation. This preliminary removal of water and heat prevents catalyst degradation before it occurs, maintaining catalyst stability throughout the process.
2Manufacturing precision
If water removal is implemented between reactors, then non-selective conversions are reduced, but equipment investment and operational complexity increase
Solution Approach 1:
Water is extracted and removed from the reaction stream between reactors. This extraction prevents water from participating in non-selective reactions that would reduce product selectivity, while the removal is implemented at strategic points to balance selectivity improvement with equipment requirements.
Solution Approach 2:
Water removal is applied locally at specific points in the process where it most effectively prevents non-selective conversions. Rather than removing water throughout the entire process, the intervention is targeted at interstage locations where it provides maximum benefit to product selectivity.
3Temperature
If exothermic reactions are reduced through heat removal, then temperature control is improved, but energy output and reaction rate may decrease
Solution Approach 1:
Heat removal is implemented periodically at interstage locations rather than continuously throughout the reaction. This periodic heat removal allows exothermic reactions to proceed at high rates in each stage, achieving good temperature control while maintaining high overall productivity through the staged approach.
Solution Approach 2:
The heat removal system is designed to dynamically balance temperature control with reaction rate requirements. By removing heat at specific stages rather than uniformly, the system maintains optimal temperatures for catalyst stability while preserving the exothermic drive for high reaction rates in each reaction zone.
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
This approach increases the yield and selectivity of LPG hydrocarbons, improves catalyst stability, and reduces the need for frequent regeneration, leading to economic benefits and reduced greenhouse gas emissions by utilizing renewable carbon sources effectively.
Implementation Method 1
synthesis gas containing a mixture of hydrogen and carbon monoxide (CO) is subjected to successive cleavage of C—O bonds and formation of C—C bonds with the incorporation of hydrogen
Implementation Method 2
partial oxidation reforming and autothermal reforming (ATR), based on the exothermic oxidation of methane with oxygen
Implementation Method 3
Steam methane reforming (SMR), in contrast, uses steam as the oxidizing agent
Implementation Method 4
contacting a synthesis gas feed comprising H2 and CO with an LPG synthesis catalyst system to produce an LPG synthesis effluent comprising the LPG product
Data Source
AI summary
Processes are disclosed for the production of liquefied petroleum gas (LPG) hydrocarbons, utilizing both alcohol (e.g., methanol) synthesis and in situ dehydration of the alcohol to hydrocarbons, and particularly propane and/or butane. The strategic implementation of water and/or heat removal, as well as adjustments to amounts of water and/or heat removed, have been discovered to result in important process improvements, such as in the performance of catalyst systems used in these processes. Performance advantages may reside, for example, in increased LPG hydrocarbon yield and/or selectivity, increased catalyst stability, or, for a given LPG synthesis reactor, decreased exotherm and/or decreased maximum temperature. Performance parameters associated with reduced reaction temperatures may advantageously facilitate the use of a wider selection of reaction systems, such as a fluidized bed reactor, which may further improve material and heat distribution, and therefore overall process control.