Chennai Petroleum Corporation Limited (CPCL), the company's history dates back to when it was incorporated in 18th November of the year 1965. Formerly known as Madras Refineries Limited (MRL) was formed as a joint venture between the Government of India (GOI), AMOCO and National Iranian Oil Company (NIOC) having a share holding in the ratio 74%: 13%: 13% respectively. CPCL has two refineries with a combined refining capacity of 10.5 Million Tonnes Per Annum (MMTPA). The Manali Refinery has a capacity of 9.5 MMTPA and is one of the most complex refineries in India with Fuel, Lube, Wax and Petrochemical feedstocks production facilities. CPCL's second refinery is located at Cauvery Basin with 1.0 MMTPA at Nagapattinam. The main products of the company are LPG, Motor Spirit, Superior Kerosene, Aviation Turbine Fuel, High Speed Diesel, Naphtha, Bitumen, Lube Base Stocks, Paraffin Wax, Fuel Oil, Hexane and Petrochemical feed stocks.
In the year 1985, AMOCO disinvested in favour of GOI and the shareholding percentage of GOI and NIOC stood revised at 84.62% and 15.38% respectively. A Propylene Plant with a capacity of 17,000 tonnes per annum was commissioned in the year 1988 to supply petrochemical feedstock to neighbouring downstream industries. CPCL had entered into an agreement with Balmer Lawrie & Co. Ltd. Chennai in September 1991 for supply of Anti-oxidants Feedstock and the first supply was successfully started in March of the year 1992. GOI disinvested 16.92% of the paid up capital in favor of Unit Trust of India, Mutual Funds, Insurance Companies and Banks on 19th May 1992, thereby reducing it's holding to 67.7 %. During the year 1992, the company commissioned its Hexane Plant with a production capacity of 25,000 Metric Tonnes per annum and also commissioned a Sewage Water Treatment Plant with capacity of 2.5 MGD.
The initial unit of the company was set up in Cauvery Basin at Nagapattinam with a capacity of 0.5 MMTPA in the year 1993 and later on its capacity was enhanced to 1.0 MMTPA. The public issue of CPCL shares at a premium of Rs. 70 (Rs. 90 to FIIs) in 1994 was over subscribed to an extent of 27 times and added a large shareholder base of over 90000. In 1995, CPCL's new boiler for co-generation of 130 T/HR capacities to meet the increased stream load was commissioned. The company had commissioned the LPG separation unit & steam turbo generator in the year 1996 at CBR. During the year 1997, as to satisfy the customers and to meet the demand, CPCL had launched the 500N grade of LOBS in the field of LOBS. In the same year 1997, The Company obtained clearance from the Govt. to expand the capacity at Manali by another 3 million tonnes per annum.
As a part of indigenisation of reverse osmosis membranes in collaboration with Central salt and marine chemicals research institute the R&D unit of the company had commissioned a reverse osmosis pilot plant in the year 1997 with capacity of 50,000 liters per day capacity to study the membrane performance. The Joint Venture was considered between Petronas, IOC and MRL in 1997 for setting up an underground cavern storage facility at the Ennore liquefied natural gas import station. The company signed a MOU with Indian Oil Corporation Ltd in the year 1998 to work jointly on projects of mutual benefit including a refinery project in Southern India.
The Tamil Nadu Electricity Board signed a power purchase agreement with the company during the year 1999. During the year 2000, Indian Additives Ltd a joint venture of the company, and Chevron Chemical Company US, had ceased to be a subsidiary of the company. In the same year, CPCL had launched crumb rubber modified bitumen for laying high quality and cost effective roads. The Company changed its name to Chennai Petroleum Corporation Ltd (CPCL) with effect from 6th April of the year 2000. As a part of the restructuring steps taken up by the Government of India, Indian Oil acquired equity from GOI in 2000-01 Currently IOC holds 51.88% while NIOC continued its holding at 15.40%. During the year 2001, CPCL and EDL India Pvt Ltd had signed a MoU to set up a 14.85 MW waste-to-energy project using municipal solid waste.
The Chennai Port Trust had signed an agreement with the company in the year 2003 to set up a Tier I Oil Spill Response facility at the Chennai port. The Propylene Plant unit was revamped to enhance the propylene production capacity to 30,000 tonnes per annum in the year 2004. During the year 2005, the company and Indian Oil Corporation collectively made a deal to provide project consultancy on crude pipeline. The crude throughput for the year 2005-06 was 10.36 million metric tonnes, and has surpassed its yearly target. Highest ever production was achieved in the value added products like LPG, Petrol, Aviation Turbine Fuel, and High Speed Diesel. The total exports through Indian Oil were 642 TMT during the year 2005-06.
In Manali Refinery, to enhance the availability of water, an additional 2.5 MGD capacity Sewage Reclamation Plant consisting of Biological Treatment, Chemical Treatment, Ultra Filtration and Reverse Osmosis was commissioned in December of the year 2006. The Standard & Poor (S & P), the world's leading credit rating agency, identifies CPCL as one of the seven Indian Companies having potential to emerge as Challengers to the World's leading Blue chip companies during the year 2006-07. The subsidy sharing mechanism of LPG/SKO by way of discounts offered by refineries to Marketing Companies, which was introduced in the year 2006 was withdrawn in 2006-07. As at January of the year 2008, CPCL plans to invest Rs 50 billion for revamping its Chennai refinery to enhance the quality of manufactured petroleum products. CRISIL assigned `AAA` and `P1+` for Chennai Petro`s bank facilities during April of the year 2008.