An Explanation of the Deacon Process

Henry Deacon invented the Deacon process. It is used to convert Hydrogen gas to Chlorine gas which was then used in other industries. The process is an example of how a chemical process can be developed incrementally, with improvements and other variations added overtime to produce the desired end product. This process is relatively simple concerning its overall design, but the technology required to implement it was readily available at the time it was developed. There are many patents describing variations on this basic concept. The following article gives a better understanding of the process.

The Deacon Process

Hydrogen Chloride is passed into a blast furnace and burned with air to produce chlorine and heat. The steam is separated, and the hydrogen chloride is passed into a distillation column with limestone slaked in water, where it oxidises and produces sodium hydroxide and hydrochloric acid. The latter is pumped out of the apparatus and dried with coke. It requires heat to convert this acid into chlorine gas, which is then passed through a pressure chamber at atmospheric pressure to produce hydrochloric acid gas.

The Deacons process was superseded by the chloralkali process using electrolysis. The Deacon process was used in Britain, Germany, and Switzerland.

Apparatus and Process

Deacon’s apparatus consisted of a vertical iron pressure vessel to which was welded a U-shaped conduit. The lower arm of the U contained a nickel catalyst, and it was surrounded by a solution of caustic soda (NaOH). The upper arm of the U contained an iron solution containing potassium chloride (KCl) or potassium sulphate (KSO). The gas space above the caustic soda solution was filled with steam and maintained at about pressure.

Hydrogen chloride gas was bubbled up through the sodium chloride solution, dissolving some of it. 

The solution was then cooled, and chlorine gas was liberated from the aqueous phase. The chlorine vapour and steam mixture passed through a condenser, where the vapour was condensed to a liquid. The chlorine was then passed through a reaction vessel containing caustic soda, which oxidised it. The absorption of needed hydrochloric acid takes place, and then the hydrochloric acid is vented to the outside air, and a commercially valuable bleaching powder is formed.

A cycle of operations was repeated, and the cycle time would be 10–15 min.

The Deacon process was based on hydrochloric acid. It has been suggested that hydrogen chloride is more reactive than chlorine at temperatures below, and it oxidises at a higher rate. This would account for the high temperature of the reaction. However, the Deacon process is said to have been used with hydrogen chloride at temperatures up to, which suggests that it could have been used with chlorine.

The reaction was originally carried out with steam and iron catalyst but later evolved to use hydrogen chloride gas and caustic soda solution. The chlorine gas was used to bleach (oxidise) the caustic soda solution to make a bleaching powder. Hydrogen chloride and water are gases that are easily transported through plumbing systems in industrial plants and thus can be stored safely.

Properties of Deacon Process

The Deacon process is significant because it is the first to produce chlorine on an industrial scale. Deacon’s process was followed by the chlor alkali process, making chlorine production less expensive by reducing the overall heat requirement.

Also, it produced hydrochloric acid, which had many uses in steel mills and other industries. Henry Deacon was also significant in developing this process into a commercially viable technology.

Uses and Applications of the Deacon Process

• Industries

Worldwide some industries are making use of the Deacon process for their work. The process is used in many industries, especially the manufacturing industry, and it is very useful in them.

The Deacon process has been used in many different types of industries in the manufacturing industry.

The process is used to produce chlorine-based products such as bleaching powder, denture cleaners, and ozone generators.

The oldest use of the Deacon Process is in the steel industry, where it was used to manufacture manganese dioxide to remove iron from iron ore.

The Deacon Process is also used in other industries, and mainly each process uses different components, making them unique from one another.

Advantages and Limitations of the Deacons Process

Like the manganese dioxide process before it, the Deacon process provided an efficient method of producing bleaching powder. The “acid” was vented to the atmosphere, and chlorine was used to manufacture a valuable product.

A drawback of the Deacon process was that there was no provision for capturing hydrochloric acid and using it in other processes.

However, Deacon’s process used less energy than the manganese dioxide process.

Conclusion

Henry Deacon was an Englishman born in 1803 that invented the process for producing chlorine, which he did in 1856. The Deacon process was significant because it was the first to oxidise and produce chlorine on an industrial scale. Deacon’s process was followed by the chlor alkali process, making chlorine production less expensive by reducing the overall heat requirement.

Also, the Deacon process produced hydrochloric acid, which had many uses in steel mills and other industries. Henry Deacon was also significant in developing this process into a commercially viable technology. Though, the deacon process was outnumbered by several other processes afterward.