Heavy Water Plant at Baroda is the first plant set up in the country for the production of heavy water by employing ammonia-hydrogen exchange process (monothermal).  The plant is about 8 km from Baroda railway station along national highway no.8.
    Work on HWPB was commenced in June 1970 and the project was completed in July 1977.

Process description :

Synthesis gas (a mixture of one part of nitrogen and three parts of hydrogen) containing deuterium, produced in one of the adjacent ammonia plant for their captive use, is routed through the plant at a flow rate of about 46 T/hr. at a pressure of about 640 kgs./cm².  The gas is first cooled in a heat exchanger by the outgoing cold gas from the plant to ammonia plant.

The gas is then passed through a purification unit. In this unit the impurities contained in the gas such as water, carbon monoxide, carbon dioxide and oxygen are removed and the gas is saturated with ammonia.

  The cooled and purified synthesis gas saturated with ammonia is then passed through the first isotopic exchange tower working at (-)20 degree Celsius where deuterium in the gas transferred to a counter current stream of liquid ammonia fed from the top of the tower in the presence of liquid potassium amide catalyst contained in liquid ammonia solution. The deuterium enriched ammonia from the bottom of the exchange tower is then fed to the second isotopic exchange tower where it gets further enriched by coming in contact with the synthesis gas obtained by cracking of enriched ammonia.  A part of the enriched gas and liquid from the bottom of second isotopic exchange tower is then taken to the final enrichment section where the concentration of deuterium in the ammonia can be further increased as desired upto 99.8%.

Finally, the enriched ammonia so obtained is cracked and a portion of this enriched synthesis gas is burnt with dry air to produce heavy water. However, for reasons of better recovery efficiency the concentration of deuterium in ammonia in the final enrichment section is kept at around 60%. An upgrading plant is set up to upgrade the 60% heavy water to nuclear grade.