Call for Conservation

Chemical and petrochemical industries benefit from energy saving measures

Chemical and petrochemical industries, which provide raw material, feedstock and intermediate materials to several other industries, are heavy consumers of energy. As per a report by the Confederation of Indian Industry, the country’s chemical industry is the sixth largest in the world and the third largest in Asia in terms of volume.

Given the high share of energy costs in the overall costs of these industries, it is important for them to optimise energy usage.

Power Line highlights the energy conservation measures taken by leading chemical and petrochemical firms, which have also been recognised by the Bureau of Energy Efficiency…

Reliance Industries Limited, Nagothane Manufacturing Division, Raigad, Maharashtra

The Nagothane Manufacturing Division, one of the six major manufacturing sites of Reliance Industries Limited, is located in Raigad district of Maharashtra. It is a petrochemical complex and was commissioned in 1989. Various production units in the complex produce polyethylene, polypropylene, ethylene oxide and monoethylene glycol, totalling 600 kilo tonnes per annum. The energy requirement of the complex is met through the captive generation of steam and power from its captive power plant (CPP).

Since 2010-11, the company’s energy index has been showing a decline in energy consumption. The index decreased from 4.09 GCal per million tonnes (mt) in 2010-11 to 3.54 GCal per mt in 2013-14.

During 2013-14, the unit took various energy saving measures including the installation of a small air compressor, improvement in the heat rate, lighting modification in all plants, steam turbine generator overhaul, replacement of two SL steam float traps and 15 passing-by-pass valves, CCC implementation in the CG and C3R compressors, efficient operations of furnaces and maximum utilisation of the cracker-generated waste fuel gas in the CPP.

The unit has also developed a prosteam optimiser. By using real-time data, the optimiser gives recommendations on minimising the total operating cost of the site by reducing letdowns and vents and loading more efficient equipment within the constraints. It also optimises the power purchased and the power generated through the CPP. The optimiser runs every hour in auto mode and fetches data from the IP21 for every 15 minutes and gives recommendations.

Rohm and Haas (India) Private Limited, Taloja Unit, Raigad, Maharashtra

The Rohm and Haas develops specialty and performance materials for customers and its products are used worldwide in many industrial and consumer product applications including building and construction, electronics, food and retail, household and personal care, industrial process, packaging and transportation, and water.

The company started operations in India in 1995 through its subsidiary Rohm and Hass (India) Private Limited and, in August 2003, established a manufacturing unit at Taloja to manufacture water-based latex polymer-dow coating material and polyester and polyurethane-advance functional material. The unit, which has advanced automation and process control design, is spread across a 70,000 sq. m plot.

The energy conservation projects at Taloja have resulted in both tangible and intangible savings. The 2013-14 energy conservation programme covered 12 projects and entailed an investment of Rs 6.6 million. It led to savings worth Rs 14.9 million,  a 12.08 per cent reduction in the unit’s specific electrical energy consumption and a 12.33 per cent reduction in its specific thermal energy consumption as compared to the previous year.

A key initiative that made this possible was the replacement of four 15 kW rated centrifugal pumps with 7.5 kW rated canned motor pumps with EFF1 rated motors used for the circulation of thermic fluid for process heating. This move entailed an investment of Rs 4.4 million and led to cost savings of Rs 1.6 million in the first year and electrical energy savings of 215,250 kWh per annum.

The unit also reduced the re-therm thermal oxidisers’ offline energy losses (due to trips caused by power fluctuations and a high lower explosive limit [LEL] in volatile organic compounds) by installing a UPS to back its control panel and modifying the LEL sensor installation. This entailed an investment of Rs 0.25 million and resulted in cost savings of Rs 1.28 million in the first year, electrical energy savings of 3,162 kWh per annum and savings of 13,918 cubic metre of LPG per annum. Meanwhile, automation of the cold DI circulation pump at an investment of Rs 50,000 led to electrical energy savings of 100,100 kWh per annum.

Another key initiative taken by the unit was the installation of a variable pressure relief valve, a dip pipe at the water circulation line and a U-loop at the hot water tank overflow line to eliminate vapour losses. This change along with automation of the hot DI water heating configuration in the DCs eliminated energy losses, which resulted in huge furnace oil savings.

Other measures to reduce energy consumption involved MDI over drum toughing time cycle reduction, T1 cooling water circulation pump replacement with HE pumps, air compressor loading/unloading optimisation, etc.

IOL Chemicals and Pharmaceuticals Limited, Barnala, Punjab

Established in 1986, IOL Chemicals and Pharmaceuticals Limited (IOLCP) is one of the leading generic pharmaceutical companies in India, and a significant player in the organic chemicals space. IOLCP has a wide presence across various therapeutic categories like pain management, anti-diabetic, anti-hypertensive and anti-convulsants. The company, which began with a small project of Rs 65 million to manufacture 4,500 tonnes per annum of acetic acid, has now diversified into a multi-product company to manufacture chemicals and active pharmaceutical ingredients.

During 2013-14, IOLCP implemented various energy conservation projects, which resulted in a decline in electrical energy consumption from 5.3 million kWh in 2012-13 to 4.5 million kWh in 2013-14. The thermal energy consumption, meanwhile, reduced by 3,067 million kCal, from 46,198 million kCal in 2012-13 to 43,131 million kCal in 2013-14.

A key initiative was the installation of the Dopp kettle to recover solvents in the isopropyl chloroacetate (IPCA) plant. Spent acid, which is discharged from the IPCA plant to the effluent treatment plant (ETP), contains traces of isopropanol and isopropyl chloroacetate solvents. In order to recover these solvents, the Dopp kettle is installed in the process, in which vacuum distillation of spent acid is done before the discharge of spent acid to the ETP, thus reducing power consumption in the ETP. The initiative resulted in electrical energy savings of 0.2 million kWh per annum with a payback period of six months.

Based on research and development (R&D) trials, the unit reduced the potassium carbonate to sodium ratio from 10:1 to 6:1 in the Isobutylbenzene (IBB) plant, and consumption from 500 kg per batch to 300 kg per batch. As a result, the unit is now able to dry potassium carbonate in a rotary vacuum dryer for two batches in a single-batch time by utilising the full capacity of the dryer. The measure led to savings of 0.4 million kWh per annum with a payback period of 17 months.

The unit also re-engineered the process parameter to increase the recovery of potassium carbonate in the IBB plant. In the old process, the potassium carbonate was recovered in the crystallisers at normal pressure. With the help of simulation software, the unit analysed operating conditions to improve the recovery of potassium carbonate and then generated the data. The results of the analysis showed that the recovery of potassium carbonate increased with the decrease in the operating pressure of the crystallisers. With the help of R&D data, the unit implemented the revised operating parameter in the plant. By creating a vacuum in the crystalliser the quantity of mother liquor reduced, which ultimately increased the recovery of potassium carbonate. The re-engineering resulted in electrical energy savings of 0.5 million kWh per annum and steam savings of 2,000 million tonnes per annum.

Conclusion

Power costs constitute one-third of the production costs of the chemical and petrochemical industries and it is, therefore, imperative for the sector to be energy efficient. The initiatives taken by the companies mentioned above have set examples for companies looking to secure their energy requirements in the long term.

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