Batch hydrogenation is performed in autoclaves using agitator-type or loop-type reactors. In agitator reactors, fats or oils with nickel catalyst are sparged with hydrogen gas introduced through a specially designed sparger at the bottom. This slower, selective process is well-suited to small capacity plants and allows precise control of product characteristics. In loop reactors, vigorous circulation in a venturi loop ensures rapid mixing and very short residence times at high temperatures. This approach achieves full hydrogenation efficiently, delivering low iodine values while minimising nickel catalyst consumption. Catalyst removal is handled by candle filters with auto-wash systems for operational ease.

Semi-continuous systems combine features of batch and continuous processes, with feed and discharge arrangements enabling smoother operation. Both agitator and loop reactors can be used, but are optimised with special agitation systems that shorten the hydrogenation cycle. By integrating regenerative heating and cooling, these systems significantly reduce steam consumption and overall power demand, making them more economical than batch reactors while maintaining flexibility in selectivity and throughput.

In continuous hydrogenation, oil or fatty acid mixed with nickel catalyst is fed into a tall reactor tower along with a high flow of hydrogen gas. The reaction proceeds as fresh feed enters and hydrogenated product is discharged continuously from opposite ends of the reactor. This setup allows excess hydrogen to be compressed and reused, maximising efficiency. Designed for large-capacity operations, continuous plants enable full automation and provide the lowest operating costs through high hydrogen utilisation and uninterrupted processing.