Hydrogen Chloride Gas Dehydration With Staged Sulfuric Acid

The dehydration process is divided into multiple stages with different sulfuric acid concentrations. The first drying column uses concentrated sulfuric acid (93-98 wt%) for initial dehydration, while the second drying column uses higher concentration sulfuric acid (96-98 wt%) for final dehydration. This segmentation allows each stage to perform its specific function optimally, improving overall dehydration reliability while reducing total sulfuric acid consumption compared to using only high-concentration acid throughout.

The patent changes the concentration parameter of sulfuric acid across different stages of the dehydration process. By using 93-98 wt% sulfuric acid in the first stage and 96-98 wt% in the second stage, the system optimizes the balance between dehydration effectiveness and acid utilization efficiency. This parameter variation resolves the contradiction by matching acid concentration to the specific dehydration needs at each stage.

The system segments the dehydration task into two columns handling different dehydration loads. The first column with 93-98 wt% sulfuric acid handles the bulk water removal from high-concentration HCl gas, providing high treatment capacity. The second column with 96-98 wt% sulfuric acid provides the final dehydration guarantee, ensuring reliability. This segmentation resolves the contradiction between treatment capacity and dehydration certainty.

The patent applies different sulfuric acid concentration parameters to different stages: 93-98 wt% for the first stage (high capacity) and 96-98 wt% for the second stage (high reliability). This parameter change strategy allows the system to achieve both high treatment capacity and high dehydration certainty simultaneously.