Off-line Treater Regeneration Using Thermosyphoning
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Solution Overview
Problem
Current regeneration processes for desiccants in polyolefin production are costly and time-consuming, consuming significant nitrogen and fuel gas, and taking longer than a month in some cases.
Innovation Solution
A method involving a heating phase followed by a cooling phase to regenerate desiccants in an off-line treater, using a regenerating stream to separate impurities and recycle the desiccant, with thermosyphoning to cool the treater efficiently, reducing the need for nitrogen and shortening cooling times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If current regeneration processes are used for desiccants, then desiccant regeneration is achieved, but nitrogen and fuel gas consumption is high and regeneration time exceeds a month
Solution Approach 1:
The patent changes the temperature parameter by heating the desiccant to elevated temperatures (e.g., 100-200°C or higher) to accelerate impurity desorption. This temperature parameter change enables faster regeneration (reducing time from over a month to feasible operational cycles) while using process heat rather than consuming additional fuel gas, thus resolving the contradiction between regeneration time and energy consumption
Solution Approach 2:
The patent uses the desiccant's own thermal capacity and the heat already present in the system (process heat, hot gases from other operations) to drive the regeneration process. By utilizing self-heating capabilities and recovering heat within the system, the process eliminates the need for external fuel gas consumption while maintaining effective regeneration speeds, thus resolving the contradiction between energy consumption and regeneration effectiveness
2Reliability
If current regeneration processes are used for desiccants, then desiccant regeneration is achieved, but regeneration costs are high due to nitrogen and fuel gas consumption
Solution Approach 1:
The patent optimizes temperature and pressure parameters to achieve effective regeneration at conditions that utilize available process heat rather than requiring expensive fuel gas. By adjusting these parameters to match available heat sources, the process maintains regeneration effectiveness while eliminating additional energy costs, thus resolving the contradiction between reliability and energy loss
Solution Approach 2:
The patent converts waste heat from other process operations into the driving force for desiccant regeneration. By utilizing heat that would otherwise be discarded (a harmful waste product) to perform the useful function of regeneration, the process eliminates the need for expensive fuel gas while maintaining effective desiccant regeneration, thus resolving the contradiction between reliability and loss of energy
3Temperature
If traditional cooling methods are used for the treater, then cooling is achieved, but cooling time is excessive and nitrogen consumption is high
Solution Approach 1:
The patent uses hydraulic cooling by circulating a liquid coolant (such as water or process liquid) through heat exchange surfaces or directly through the treater system. This hydraulic cooling method transfers heat much more efficiently than gas-based methods, reducing cooling time from excessive durations to practical operational cycles while eliminating nitrogen consumption entirely, thus resolving the contradiction between temperature control and time loss
Solution Approach 2:
The patent replaces the mechanical/gas-based cooling system (using nitrogen flow) with a thermal conduction-based liquid cooling system. This substitution leverages the superior heat capacity and thermal conductivity of liquids compared to gases, achieving rapid cooling without the time delays and resource consumption associated with traditional nitrogen-based cooling methods, thus resolving the contradiction between temperature control and cooling time
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 method effectively regenerates desiccants, reducing costs and time, and utilizes existing recycle streams to minimize nitrogen consumption and emissions, improving the efficiency of polyolefin production.
Implementation Method 1
a desiccant which traps the impurities
Implementation Method 2
thermosyphoning a regenerating gas, nitrogen, an olefin-free diluent, or combinations thereof in a closed-convection loop of the off-line treater to cool the off-line treater
Data Source
AI summary
A treater regeneration system in a polyolefin production system, the treater regeneration system comprising an off-line treater receiving a first portion of a regenerating stream and regenerating a desiccant in the off-line treater to yield a regenerating effluent stream, where the regenerating stream comprises a regenerating medium, and where the regenerating effluent stream comprises the regenerating medium, water and an impurity; a decanter receiving at least a portion of the regenerating effluent stream to yield the regenerating stream and a water stream, wherein the water stream comprises the water; and a stripper receiving a second portion of the regenerating stream to yield an impurity stream and a process recycle stream, wherein the impurity stream comprises at least a portion of the impurity, and wherein the process recycle stream comprises the regenerating medium of the second portion of the regenerating stream.