The Chemistry of Sustainability

As energy prices rise, and regulation increases, improved energy efficiency makes environmental and economic sense. Muriel Axford explores how in the energy intensive chemicals industry, small changes can lead to big savings very quickly.

According to the European Chemical Industry Council (Cefic) energy use in the chemical sector can account for up to 60% of a producer's costs. Unsuprisingly then it could be argued that the chemical sector has been among the leaders in seeking to improve energy efficiency for a number of years.

US-based Dow Chemical is just one example and puts the business case for energy efficiency simply; "Saving energy makes the company money. Dow benefits from wider uptake of energy efficiency standards through less upward price pressure on the hydrocarbons it uses as feedstock and greater demand for its efficiency related products."

Dow adds that rising energy prices meant that between 2002 and 2007 its annual fossil fuel bill tripled. The company has for many years been developing and implementing a comprehensive energy management system at all levels of its operations.

Some of Dow's main energy saving work includes selection of the most energy efficient equipment. At the company's site in Seadrift, Texas in the US, an air compressor incorporating a wheel design was installed.

This resulted in a fall off in the consumption of fuel to the gas turbine used to drive the compressor.

"Dow adds that rising energy prices meant that between 2002 and 2007 its annual fossil fuel bill tripled."

The old machine consumed some 8000 pounds per hour of fuel gas for maximum air flow. The new machine brought this down to 6000 pounds per hour.

Rewarding reductions

In 2010 US chemical industry body the American Chemistry Council (ACC) recognised the achievements of Dow Chemical along with eleven others in the area of energy efficiency awarding them the annual Responsible Care Energy Efficiency Award.

According to the ACC the twelve winning projects achieved a saving of 11.1tn British Thermal Units (BTUs) between them.

As well as Dow Chemical; DuPont, ExxonMobil Chemical Company, Marathon Petroleum Company and WR Grace & Co were among those recognised for ongoing energy efficiency at their operations.

As well as ongoing projects to improve the use of energy at existing production plants, new technologies are leading to major improvements in production capacity.

During the first quarter of 2010, engineering and construction company Uhde, along with Bayer MaterialScience signed a contract for the construction of a 20,000t/year chlorine plant located at the Krefeld-Uerdingen chemical park in Germany by 2011.

The plant will be the first to use Bayer MaterialScience's oxygen-depolarised cathodes which will be used in the electrolysis cells developed by Uhdenora / Uhde to produce chlorine on an industrial scale.

As the electrochemical production of chlorine is currently one of the most energy intensive processes in the chemical industry, thecompany hopes to cut the energy required to produce chlorine by up to 30% compared with standard membrane technology and indirectly reduce annual carbon dioxide emissions by up to 10,000t.

In the national interest

Government funding is also spurring development in energy saving technologies.

During August 2010, Eastman Chemical Company and Eltron Research & Development signed a joint development agreement for the scale up and pilot testing of Eltron's advanced membrane system for hydrogen separation and carbon dioxide capture.

"Advanced control systems are also playing an important role in improving energy efficiency."

The $8m development project is sponsored by a cooperative agreement from the US Department of Energy (DoE).

Eltron's metallic membrane system extracts pure hydrogen from a mixed gas stream. The hydrogen can be used for clean power generation, chemicals synthesis and other applications.

Eltron's technology is said to offer the potential to considerably reduce the capital and operating costs of producing industrial hydrogen in conjunction with carbon dioxide capture and storage.

The technology has been under development in Eltron's laboratory for eight years, supported by significant funding from the DoE's Office of Fossil Energy and their National Technology Laboratory. A pilot demonstration plant is due to be completed at Eastman Chemical's coal gasification facility in Kingsport, Tennessee, during 2012.

Tracking targets

Advanced control systems are also playing an important role in improving energy efficiency. Honeywell has developed what it calls its 'Energy Dashboard', which gathers information from various instruments and systems so energy consumption can be tracked against dynamic energy targets.

Users are able to establish specific goals for improving energy use and emissions reduction objectives. Use of integrated energy management solutions is said to have a number of benefits, including reduced heat and power production costs.

While process improvements mean immediate changes, companies are looking at new ways to bring about energy efficiency. During the second half of 2009 German chemical major BASF along with Delta Electronics began working together to use magnetocaloric technology to develop new cooling systems.

Cooling systems based on this technology have the potential to significantly reduce energy consumption. Magnetocalorics technology removes the need for gaseous refrigerants and is therefore quieter and causes less vibration than conventional compressor type refrigerators. Being compact it also has the potential to be used on domestic cooling applications.

"Government funding is also spurring development in energy saving technologies."

One of the main research goals in the area of magnetocalorics is to save energy across a wide range of applications ranging from cryo-production in the process industry, through to car air conditioning.

"Cooling equipment accounts for about one-fifth of domestic energy consumption. The refrigerator is in effect the most important home appliance in terms of potential energy savings because every household has one, and because it is one of the most power hungry appliances," commented Olaf Rogge, Magnetocalorics Project leader at BASF Future Business.

Delta Group is among the world's leading suppliers of power management solutions, components and renewable energy solutions.

In the short term it is the small changes that make the big differences. GE Oil & Gas redesigned its DVS Centrifugal Pump for liquid pipeline applications.

The company said that oil and gas operators are constantly seeking reliable, proven and cost –effective solutions to improve performance and reduce their environmental footprint. Running at full capacity the company says that the Ecomagination qualified centrifugal pump saves the energy equivalent of the electricity consumed by over 200 US homes each year.