Fischer-Tropsch Effluent Storage Temperature and Inert Atmosphere
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Solution Overview
Problem
The Fischer-Tropsch process produces effluents that are difficult to store and incorporate into conventional fuel pools due to their high pour point and content of olefins, which can form undesirable polymers and block catalytic beds, requiring complex unit shutdowns and inefficient operation.
Innovation Solution
Storing the light fraction from the Fischer-Tropsch effluent at a temperature below 20°C and the heavy fraction between 80°C and 230°C under an inert atmosphere, with specific conditions for each fraction to prevent polymer formation and maintain process efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the light fraction is stored at ambient temperature, then the storage conditions are simple, but polymers form and block catalytic beds
Solution Approach 1:
The patent applies inert atmosphere by storing the light fraction under nitrogen or other inert gases to prevent oxidation and polymerization reactions. This creates a chemically stable environment that eliminates the harmful polymer formation while maintaining operational simplicity, as the inert atmosphere can be maintained through standard storage vessel purging and blanketing procedures.
Solution Approach 2:
The patent changes the storage temperature parameter from ambient temperature to refrigerated temperatures (typically 0-10°C or below). This parameter change slows down the kinetic energy of molecules, reducing the rate of polymerization reactions and preventing rubber formation. The refrigerated storage condition maintains the light fraction in a stable state without compromising ease of operation, as refrigeration is a standard industrial storage method.
2Object-affected harmful factors
If downstream units are shut down to prevent polymer formation, then polymer formation is prevented, but production efficiency decreases
Solution Approach 1:
The patent applies preliminary action by implementing preventive storage measures (refrigeration and/or inert atmosphere) before the light fraction enters the downstream units. This preliminary protection ensures that polymerization does not occur during storage, eliminating the need for downstream unit shutdowns. The Fischer-Tropsch synthesis unit can continue operating continuously, maintaining high production efficiency while the protected light fraction is stored safely.
Solution Approach 2:
The patent introduces an intermediary storage system with controlled temperature and atmosphere between the Fischer-Tropsch synthesis unit and the downstream hydrotreating/hydrocracking units. This intermediary buffer allows decoupling of the synthesis unit operation from downstream unit availability, enabling continuous synthesis operation while downstream units can be maintained, restarted, or operated at optimal conditions without forcing shutdowns.
3Use of energy by moving object
If the light fraction is stored without temperature control, then energy consumption is low, but rubbers form and block reactors
Solution Approach 1:
The patent changes the storage temperature parameter from ambient to refrigerated conditions (0-10°C or below). This parameter change thermodynamically stabilizes the light fraction by reducing molecular kinetic energy and reaction rates, preventing polymerization and rubber formation. While this increases energy consumption for refrigeration, it is a controlled and necessary energy input to prevent the much larger operational disruptions caused by reactor blockages.
Solution Approach 2:
The patent applies inert atmosphere storage using nitrogen or other inert gases to create a chemically stable environment that prevents oxidation and polymerization reactions. This approach requires minimal energy input compared to refrigeration, as it primarily involves gas circulation and vessel purging. The inert atmosphere effectively prevents rubber formation by eliminating the oxygen and reactive conditions necessary for polymerization.
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 prevents the formation of undesirable rubbers, allows for continuous operation of downstream units, and improves the yield and quality of middle distillates by maintaining the effluents in a stable, usable state during shutdowns and restarts.
Implementation Method 1
the light fraction resulting from the Fischer-Tropsch effluent has to be stored in a vessel at a temperature of less than 20° C. and more preferably of less than 15° C. and more preferably still of less than 10° C.
Implementation Method 2
the storage of the waxes resulting from the Fischer-Tropsch synthesis in a vessel maintained at a temperature of between 90° C. and 130° C., in order to ensure the flow of the products
Implementation Method 3
under an inert atmosphere, in order to prevent the formation of peroxides and/or of rubbers
Data Source
AI summary
Process for the production of middle distillates from a paraffinic feedstock produced by Fischer-Tropsch synthesis comprising at least one light fraction, known as condensate, and a heavy fraction, known as waxes, in which:the said light fraction is stored in a vessel (B) maintained under an inert atmosphere and in which the temperature inside the vessel is maintained at a value of less than 20° C.;the said heavy fraction is stored in a vessel (C) maintained under an inert atmosphere and in which the temperature inside the vessel is maintained at a value of between 80 and 230° C.