Molecular Sieve Dehydration Regeneration for Stable Gas Heating Value
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Solution Overview
Problem
Molecular sieve-based dehydration units experience heating value spikes during regeneration due to the release of trapped heavy hydrocarbons, which disrupt downstream processes requiring a consistent gas heating value.
Innovation Solution
A regeneration process involving depressurization, sweeping with unheated regeneration gas at a controlled flow rate and temperature, followed by heating and cooling steps to stabilize the heating value by removing trapped hydrocarbons without exceeding a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the molecular sieve-based dehydration unit is regenerated using conventional heating methods, then the adsorptive capacity is restored, but heating value spikes occur in the product gas
Solution Approach 1:
The regeneration process is divided into multiple sequential stages: depressurization stage, sweeping stage with unheated regeneration gas, and heating stage. This segmentation allows controlled removal of trapped hydrocarbons at different phases, preventing sudden heating value spikes while maintaining adsorptive capacity restoration.
Solution Approach 2:
Before applying heat to regenerate the molecular sieve, the process first depressurizes the unit and introduces unheated regeneration gas to sweep away trapped heavy hydrocarbons. This preliminary action removes the source of heating value spikes before the heating stage begins, ensuring stable product gas heating value.
2Productivity
If the molecular sieve-based dehydration unit operates at high pressure during dehydration, then dehydration efficiency is improved, but trapped heavy hydrocarbons are released during regeneration causing heating value fluctuations
Solution Approach 1:
The process dynamically changes operating parameters during regeneration: pressure is reduced from operating pressure to lower pressure, temperature is increased from ambient to elevated temperatures in staged manner, and flow rates are adjusted. These parameter changes enable controlled release of trapped hydrocarbons while maintaining dehydration efficiency during normal operation.
3Object-generated harmful factors
If the regeneration gas flow rate is increased to remove trapped hydrocarbons, then heating value stability is improved, but energy consumption increases
Solution Approach 1:
The regeneration process uses periodic introduction of unheated regeneration gas at controlled flow rates during the sweeping stage, followed by periodic heating stages. This periodic action pattern effectively removes trapped hydrocarbons and stabilizes heating value while optimizing energy consumption by avoiding continuous high-flow rate operation.
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 effectively minimizes heating value fluctuations, ensuring a stable product gas heating value and maintaining plant capacity by smoothly removing trapped hydrocarbons during regeneration.
Implementation Method 1
at least partially saturating adsorbers included in the molecular sieve-based dehydration unit with water and trapped heavy hydrocarbons from the wet hydrocarbon gas
Implementation Method 2
heating the molecular sieve-based dehydration unit with the heated regeneration gas at a flow rate that is greater than the sweeping flow rate for a duration sufficient to restore the adsorptive capacity
Data Source
AI summary
An improved method of restoring the adsorptive capacity of a molecular sieve-based dehydration unit utilized in drying a hydrocarbon gas. The method includes a gas dehydration step, a depressurization step, a sweeping step, a heating step and a cooling step. During the sweeping step, a regeneration gas is introduced into the molecular sieve-based dehydration unit at a sweeping temperature and sweeping flow rate to result in the smooth removal of heavy hydrocarbons prior to the heating step. The improved regeneration process decreases spikes in the heating value of a product gas after blending with the regeneration gas that occur during the heating step of prior art regeneration processes.