At a time when the country’s medical oxygen supply for the treatment of Covid-19 patients was in short supply, India’s Bombay Institute of Technology (IIT-B) established a demonstration unit to convert nitrogen generators. The factory settings are fine-tuned to become an oxygen generator.
The oxygen produced by the plant in the IIT-B laboratory was tested and found to have a purity of 93-96% and a pressure of 3.5 atmospheres.
Nitrogen plants take in air from the atmosphere and separate oxygen and nitrogen to produce liquid nitrogen, which can be found in various industries such as oil and gas, food and beverages. Nitrogen is dry in nature and is commonly used to wash and clean oil and gas tankers.
Milind Atrey, Chair Professor of the Institute of Mechanical Engineering of IIT-B, together with Tata Consulting Engineers Co., Ltd. (TCE), demonstrated a proof of concept for the rapid conversion of a nitrogen plant into an oxygen plant.
The nitrogen plant uses pressure swing adsorption (PSA) technology to suck air from the atmosphere, filter impurities and extract nitrogen. Oxygen as a by-product is released back into the atmosphere. The nitrogen plant has four components-a compressor to control the suction air pressure, an air container to filter impurities, a PSU unit to separate, and a buffer container to send and store the separated nitrogen.
Atrey and the team from TCE suggested changing the filter used to extract nitrogen in the PSA unit to a filter that can extract oxygen.
"In a nitrogen plant, the air pressure is controlled, and then impurities such as water vapor, oil, carbon dioxide, and hydrocarbons are removed. After this step, the purified air enters the PSA chamber equipped with carbon molecular sieves or filters to separate nitrogen. And oxygen. We recommend replacing the sieve with a sieve that can separate oxygen,” said Atrey, IIT-B cryogenic engineering expert and R&D director.
The team replaced carbon molecular sieves with zeolite molecular sieves in the PSA nitrogen device of the Institute's Refrigeration and Cryogenic Laboratory. Zeolite molecular sieves are used to separate oxygen from the air. By controlling the flow rate of the vessel, the researchers were able to transform a nitrogen plant into an oxygen plant. Spantech Engineers, a city company that handles the production of PSA nitrogen and oxygen devices, cooperated with the pilot project and installed the required device components in IIT-B as a skid for evaluation.
The pilot project aims to find a quick and easy solution to the problem of severe hypoxia in medical institutions across the country.
Amit Sharma, Managing Director of TCE, said: “The pilot demonstrates how innovative solutions for emergency oxygen production using existing infrastructure can help the country tide over the current crisis.”
"It took us about three days to convert. This is a simple process that can be done quickly in a few days. Nitrogen plants across the country can use this technology to convert their plants into oxygen plants," Atrey said .
Announced on Thursday morning, this pilot study has attracted the attention of many policymakers. "We have received interest from many government officials, not only in Maharashtra, but from all over the country. They are very interested in how to expand and implement this in existing nitrogen plants. We are currently streamlining the process, To help existing factories adopt this model," Atrey added.
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