Compressor Exhaust Gas Scrubbing for Low-Complexity Impurity Removal
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Solution Overview
Problem
Conventional exhaust gas treatment systems for oxyfuel combustors require large and complex equipment to remove impurities, leading to increased installation costs and inefficiencies, particularly in handling water-soluble impurities like sulfur oxides and hydrogen chloride.
Innovation Solution
A compressor-based impurity removal system that uses a series of compressors and aftercoolers to stepwise compress and cool exhaust gas, with an alkaline agent supplied upstream of the aftercooler to dissolve and separate impurities, and a pH sensor and controller to optimize alkaline agent usage, effectively removing water-soluble impurities using simple equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional wet desulfurizer and denitrator equipment is used to remove impurities, then impurity removal effectiveness is improved, but equipment size and structural complexity increase significantly
Solution Approach 1:
The patent combines multiple impurity removal functions (desulfurization, denitrification, hydrogen chloride removal) into a single integrated scrubber unit. The scrubber simultaneously contacts exhaust gas with alkaline solution to remove sulfur oxides, nitrogen oxides, and hydrogen chloride through chemical reactions, eliminating the need for separate wet desulfurizer and denitrator equipment while maintaining effective impurity removal.
Solution Approach 2:
The scrubber is designed as a multi-functional device that performs multiple impurity removal operations simultaneously. By using alkaline solution (such as calcium hydroxide or sodium hydroxide) as the cleaning medium, the single scrubber can remove various acidic impurities (SOx, NOx, HCl) through neutralization reactions, making the equipment versatile and reducing overall system complexity.
2Productivity
If large-scale conventional equipment is installed to handle exhaust gas impurities, then impurity removal capacity is improved, but installation cost increases
Solution Approach 1:
By merging multiple impurity removal functions into a single scrubber unit, the patent reduces the total equipment volume and material requirements compared to installing separate large-scale desulfurizer and denitrator systems. This integration maintains adequate impurity removal capacity while significantly reducing installation costs through reduced equipment quantity and simplified installation procedures.
Solution Approach 2:
The patent changes the operational parameters by using alkaline solution instead of conventional separate treatment methods. This parameter change allows a single compact scrubber to achieve the impurity removal capacity that would otherwise require multiple large equipment units, thereby reducing installation costs while maintaining productivity.
3Reliability
If water spraying is used to remove water-soluble impurities, then sulfur oxides and hydrogen chloride removal is improved, but nitrogen monoxide remains unremovable due to water insolubility
Solution Approach 1:
The patent changes the chemical parameter by using alkaline solution (higher pH) instead of pure water. This parameter change enables the removal of not only water-soluble impurities like sulfur oxides and hydrogen chloride but also nitrogen oxides through chemical neutralization reactions, thereby expanding the versatility of the impurity removal system to handle all major acidic impurities in the exhaust gas.
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 system effectively removes water-soluble impurities, reducing equipment size and complexity, and lowering installation costs while maintaining high removal efficiency of sulfur oxides and hydrogen chloride, and preventing corrosive damage to equipment.
Implementation Method 1
aftercoolers for cooling the exhaust gas from the respective compressors, water condensed by the cooling being discharged as drain
Implementation Method 2
an alkaline agent supply unit for supplying an alkaline agent to at least an upstream side of the aftercooler in a first one of the impurity separators, the impurities in the exhaust gas being discharged through the drain containing the alkaline agent separated by the impurity separator
Data Source
AI summary
Impurities in exhaust gas from oxyfuel combustor are removed using simple equipment to reduce installation cost. Compressor-based impurity removal system for compressing exhaust gas mainly composed of carbon dioxide from combustor before supply to carbon dioxide liquefier for removal of impurities in exhaust gas has impurity separators with compressors for compressing exhaust gas from combustor stepwisely to target pressure for liquefaction of carbon dioxide and with aftercoolers for cooling exhaust gas compressed by compressors, water condensed by cooling being discharged as drain, and alkaline agent supply unit for supplying alkaline agent to at least upstream side of aftercooler in first impurity separator. Impurities in exhaust gas are discharged through drain including alkaline agent.