The building blocks for the utilization of wet gas scrubbers

The usage of packings in wet gas scrubbers

Packings are used in wet gas scrubbers to aid the cleaning of gas in a scrubber column. They are complemented by washing liquid running against the flow of the gas. The size and shape of packings can vary along with the components of the scrubber column which can include liquid distributors and droplet separators depending upon the use case. To allow for different usage, the features of packings also vary such as their resistance to corrosion, weight, and cost. Packings provide a large surface area and speed up the gas's cleaning process. Packings can last as long as the wet gas scrubber column itself, in adverse conditions, the packings can sometimes become unusable much faster due to contamination, collapse, corrosion, contamination, or breakage.  

Which packings do you use in wet gas scrubbers?

The type of packings used depends upon the process as well as the nature of the gas, the washing liquid, temperature, and the pressure of the process. Acidic gases are often cleaned with packings made of acid-resistant stones. For every 2,500 to 6,000 mm height of packing, fluid redistributors are often required - they help to keep packings distributed evenly and ensure constant contact between the cleaning liquid and the gas. Nozzles are often used for fluid distributors, but they can jam the column. When using liquid distributors, flat trays are often used to aid the flow of the gas and the washing liquid.

Pro’s and cons of using packings in wet gas scrubbers

While initial packings were made up of ceramics, modern usage involves metal or plastic materials. However, both have their limitations as metal packings cannot be used for corrosive gases and plastic packings are unsuitable for use with high temperatures. Most scrubber columns of the wet gas scrubber use the countercurrent principle in their design and hence the drop in pressure depends upon the gas and the opposing flow of the washing liquid. The higher the pressure drop; the higher will be the operational cost of the process. Hence, most wet gas scrubbers use washing liquid and gas flow limits to ensure optimal performance and costs.

External influences on wet gas scrubbers

The absorption rate of the pollutant by the washing liquid also depends upon the temperature of the gas being injected into the column. Therefore, gas coolers are often used to reduce the evaporation of washing liquid. The reactivity of the pollutants with the washing liquid is another aspect that must be considered while designing the wet gas scrubber column. Heat exchangers or cooling coils may be necessary if the reaction is exothermic and releases heat. If the washing liquid is expensive, it is often recycled and used again.

Design essentials for wet gas scrubbers

The design of the wet gas scrubber depends upon the following elements: flow rate and composition of the gas, the concentration of pollutants, efficiency of removal, the relationship between pollutants, packings, and the washing liquid, and the various physical properties of the gas such as diffusivity, viscosity, gravity, and weight. Depending upon these properties, the design of the column scrubber is selected which includes its diameter, height, surface, absorption factor, and the pressure drop along the length of the column. Sometimes, a droplet separator is used to trap and collect liquid droplets leaving atop the column for better cleaning.

How Ravebo aids companies with constructing wet gas scrubber

Ravebo is specialized in the production of custom-built wet gas scrubbers. Are you curious how wet gas scrubbers can be built for your situation? Get in touch and discuss the possibilities of gas scrubbers.