Tata Steel has developed technology to produce hydrogen by harnessing the heat from the slag, which is generated during production of steel.
The process, called hydrogen harvesting, is the effort of Tata Steel’s R&D wing. Water is split into its components of hydrogen and oxygen by spraying it over slag as hot as 1,600 degree Celsius.
The oxygen is directed back into the slag to form oxides, while the steam accompanying hydrogen gets condensed to leave only hydrogen.
“Depending on how carefully you have done it, you can get as much as 70% of hydrogen, while the rest could be nitrogen and some carbon dioxide,” Debashish Bhattacharjee, chief, R&D and scientific services, Tata Steel, told FE here recently. He said the process has successfully generated up to 73% pure hydrogen.
Hydrogen is touted as the future alternative fuel to fossil fuels such as petroleum and coal. Several auto companies worldwide are already trying their best to build systems that will allow the use of hydrogen to run the vehicles of the future.
The company’s R&D wing has also been successful in obtaining a PCT (patent co-operation treaty) certification issued by the Geneva-based World Intellectual Property Organisation (WIPO).
Bhattacharjee said that once an entity received a PCT with respect to a new process, it earned the first claim worldwide to that process, provided of course that it filed for the patent with important global patent centres within one year of the issuance of the PCT to it.
According to Bhattacharjee, when experimented on a pilot scale with 12-tonne LD slag for five minutes, the process was capable of generating as much as 3,000 litres of gas, of which around 2,100 litres was hydrogen (ie 70%).
Tata Steel, having been successful in producing hydrogen by using the technology, is now going to put the hydrogen so generated to commercial use for the first time at its small ferro-alloy plant at Bamnipal, Rawmet (near Cuttack) in December.
The hydrogen to be produced would replace the petroleum-based oil that is being used for pre-heating briquettes today at the plants by using the high-temperature slag available at the plant.
“Oil is a major expenditure whose price will keep on increasing,” said Bhattacharjee. He said that use of oil also invariably involved
emission of carbon dioxide, something the industry was desperately trying to reduce because of its negative impact on the environment.
On how much money the process would save the company, Bhattacharjee said this would only be known after commercial trials in December.
“We’ll now try to slowly replace oil with the hydrogen that we generate,” he said.
Bhattacharjee, however, did not disclose the amount of investment that had gone into developing the technology or the cost of the equipment that would be required to put the process to commercial use in December.