Ranganathan replaced Narendra Kumar, who has returned back to the company's parent firm, GAIL India Ltd.
Ranganathan, an instrumentation and control engineer possessing and an MBA with specialisation in Marketing, has taken over the new assignment, the company said in a statement.
Before joining the current assignment, he was posted as Executive Director in GAIL.
IGL is a joint venture of GAIL (India) Ltd and Bharat Petroleum Corp Ltd (BPCL) with government of Delhi holding a 5 per cent equity stake.