Gas Absorption Thermal Integration via Solvent Segmentation
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Solution Overview
Problem
Current gas treatment processes using hot flash regeneration are limited in thermal integration and require significant thermal consumption, failing to reduce energy costs without increasing electrical consumption and investment costs.
Innovation Solution
A gas treatment process incorporating thermal integration through a combination of heat exchangers and a sampling of the cold rich solvent flow to enhance the regeneration efficiency, reducing energy consumption by up to 40% and maintaining low investment costs by replacing the regeneration column with a simple balloon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If hot flash regeneration is used instead of stripping regeneration, then capital expenditure is reduced and energy consumption is lowered, but thermal integration is limited and residual acid gas levels in solvent are higher
Solution Approach 1:
The patent segments the rich solvent flow into multiple streams and processes them through different heat exchange paths. One stream goes through the rich/lean solvent heat exchanger while another is flashed and heat-exchanged with desorbed gases, allowing optimized thermal integration without requiring a full stripping column
Solution Approach 2:
The patent introduces intermediate flash vessels as mediators between the absorption and regeneration sections. These flash vessels allow partial separation of acid gases at intermediate pressure, enabling better thermal integration by creating additional heat exchange opportunities with desorbed gases before final regeneration
2Loss of energy
If the CO2/rich solvent heat exchanger is placed upstream of the rich solvent/lean solvent heat exchanger, then heat recovery from CO2 effluent is improved, but thermal integration is reduced and reboiler energy consumption increases
Solution Approach 1:
The patent implements a dynamic thermal integration scheme where the CO2 effluent heat exchanger and rich/lean solvent heat exchanger are arranged in a specific sequence that optimizes heat recovery. The system dynamically balances heat exchange between different streams to maximize overall thermal efficiency while minimizing reboiler energy consumption
3Use of energy by moving object
If a heat pump is used to reduce thermal consumption, then energy efficiency is improved, but electrical consumption and investment cost increase significantly
Solution Approach 1:
The patent creates a self-service thermal integration system where heat is recovered and reused within the process itself. Rich solvent heats lean solvent, desorbed gases heat rich solvent, and flash vessels provide intermediate separation. This internal heat recycling eliminates the need for external heat pumps while maintaining energy efficiency
Solution Approach 2:
The patent recovers thermal energy that would otherwise be discarded from desorbed gases and CO2 effluent. By routing these hot streams through heat exchangers to preheat solvent streams, the system recovers waste heat and converts it into useful thermal energy, reducing overall energy consumption without additional equipment
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 substantial energy savings and maintains low investment costs by optimizing thermal integration and solvent regeneration, improving the efficiency of gas treatment without the need for extensive regeneration columns.
Implementation Method 1
a) A step of absorbing said compounds to be removed in an absorber (1) by bringing a flow of gas to be treated (101) into contact with a solvent flow
Implementation Method 2
b) A step of separation by flash in a medium-pressure flash drum (2) of co-absorbed compounds (106) from a cold, rich solvent stream (104)
Implementation Method 3
c) A heat exchange step between a fraction (104A) cold rich solvent stream (104) and the hot lean solvent stream (110) in a heat exchanger (3A)
Implementation Method 4
f) A rich solvent regeneration step (108) by heating in a reboiler (5) to obtain a regenerated biphasic solvent (109)
Implementation Method 5
g) A separation step in a low-pressure flash drum (6) of the regenerated, biphasic solvent (109)
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention concerns a system and a method for treating gas by chemical, physical or hybrid absorption of compounds to be eliminated, comprising at least: a) an absorption step by bringing a gas to be treated and a poor solvent into contact in order to obtain a treated gas and a rich solvent; b) an optional medium-pressure flash separation step; c) a step of heat exchange between a fraction of the cold rich solvent and the hot poor solvent in a first exchanger; d) a step of heat exchange between the complementary fraction of the cold rich solvent and a hot gaseous effluent in a second exchanger; e) an optional low-pressure flash separation step; f) a step of regenerating the rich solvent by heating in a reboiler; g) a low-pressure flash separation step; h) cooling of the poor solvent.