The reactor consists of a vertical bundle of small pipes, like in a heat exchanger. The number of reaction pipes depends on the production capacity required.

The SO3 stream and organic liquid are fed into the upper part and equally distributed to each reaction pipe. The liquid film formed in each pipe comes into contact with the SO3 stream and the sulphonation reaction takes place.

Each pipe is manufactured with the greatest mechanical precision in order to always ensure the same performance. During the calibration phase, the flow in each pipe can be adjusted with an accuracy of +/- 0,5%.

The reaction heat coming from this process is removed by water pumped into the reactor jacket, and controlled by a loop which maintains the optimal temperature for each product.