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Chlorine drying

The LiquiSonic® analyzer is used in different methods and product flows to detect the concentration and to optimize the quality as well as productivity. Another field of the LiquiSonic® application is the chlorine gas drying in the downstream process. The chloric gas must be removed from its water components to avoid a formation of chlorine hydrate and an increase of the corrosion behavoir at a moist content over 30 ppm.

Advantage of sonic velocity over conductivity and density

Application

The stage of dehydration typically takes place in absorption tower (scrubber), where the remaining humidity of chlorine gas is captured by highly concentrated sulfuric acid. Sulfuric acid is used as characteristic drying agent because it has hygroscopic properties; this means a strong attraction to water. 

The humid chlorine passes several scrubbers during the drying and the concentration of the H2SO4 increases from scrubber to scrubber. The higher the concentration, the more efficient is the drying efficiency. In this regard, a high concentrated H2SO(90-96%) is in the last scrubber, because the water components are reduced in the chloric gas to < 30 ppm. By removing the water components in the chlorine gas, the sulfuric acid is being diluted in the scrubber. The dilute H2SO4 is escorted in each case in the previous scrubber with lower H2SO4 concentrations.

Installation

The installation of the sensors is in the transport pipe-line DN80 of the scrubber.

concentration range of H2SO4: 70 wt% to 100 wt%
temperature range of H2SO4: 20 °C to 60 °C

The liquid-wetted sensor parts are made of HC2000.

Customer benefits

LiquiSonic® enables a reducing of labor costs by elimination of manual process steps and labor analysis: 

  • time saving: 3 h per day

Amortization: approx. 7 months

To protect equipment against corrosion, the water content must be less than 30 ppm in the chlorine gas. Through the continuous monitoring of the sulfuric acid concentration in the respective scrubber, the required purity of the chlorine gas (< 30 ppm H20) can be ensured. 

As it can see in the diagram, the LiquiSonic® measurement shows a clear signal with respect to the density and conductivity, in the concentration range of 80 - 100 m% (range where the effective drying takes place).