Opportunities – Chemicals and Plastics Manufacturing

Optimise the use of existing equipment

A range of technologies are used in the chemicals and plastics manufacturing sector including motors, pumps and fans, air compressors, boilers, lighting and HVAC systems. Many plants have equipment that is used sub-optimally or is left on when not in use. Optimising the use of this equipment can yield energy savings for little or no cost.

Some examples of opportunities in this area are outlined below.

Implement effective shut down procedures

Most manufacturing plants have energy overheads, such as energy-using equipment that is left on even when the plant is not producing anything. By analysing energy use in terms of the throughput, it should be possible to determine if energy use per unit produced (for example, kWh per tonne) is broadly consistent during the day, week or month. If it is not, then improving plant control can save energy.

Ensuring that all equipment is turned off when not in use is a simple way to reduce energy usage. PACIA has identified that one of the simplest energy savings has been switching off air-conditioning systems overnight and at weekends. Vinidex’s use of this measure at its O’Connor plant in Perth resulted in savings of $6,000 and 80 tonnes of CO2-equivalent per year. ¹

Optimise operating temperatures and pressures

The percentage yield and rate of chemical reactions is highly dependent on temperature and pressure. It may be possible to achieve energy savings through reviewing the optimal temperatures and pressures for particular chemical processes.

Ongoing innovations in catalysts can lower the activation energy barrier for chemical reactions, which reduces the temperatures and pressures needed.

Energy savings can also be made by taking the following actions:

• Ensure chemical distillation is being carried out under optimum conditions and that the products are not being over-purified.
• Decrease processing temperature, optimise cooling temperature and set thermostats to an appropriate temperature – A one-degree celsius drop in average space temperature can cut fuel consumption by about 8%. Be mindful that storing polymer granules at low temperatures can lead to the formation of condensation when the granules are moved into a warmer factory space. This can result in greater drying requirements prior to processing.
• Monitor and adjust the pressure of equipment. Qenos reported through the EEO program – ‘The boiler feed water pumps produce a higher pressure than is needed to supply water to the furnace waste heat boilers. One of the boiler feedwater pumps is a steam turbine. Slowing the pump down will reduce steam usage by approximately 500 kg/hr while still having adequate supply pressure for boiler feedwater. There is no capital investment required. Labour/engineering costs to implement will be less than $2000 and deliver an energy reduction of 12,000 gigajoules and $30,000 per year in energy savings.’ ¹

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Utilise advanced process control

Chemical and plastic process plants are complex and present an opportunity to minimise energy usage and maximise energy recovery through advanced process control (APC). APC is a systematic approach to enable dynamic optimisation of plant operations. APC involves installing hardware and software for capturing process operating data, analysing trends and developing strategies to optimise control of all relevant variables.

Organisations that have used APC and reported in through the EEO program include:¹

• Incitec Pivot Limited (IPL), who reported: ‘In 2008 IPL implemented advanced process control of its Ammonia Plant at Gibson Island. This project is saving approximately 0.1 GJ per tonne of ammonia manufactured or approximately 30,000 GJ per year. The project has also resulted in production gains of approximately 5 tonnes per day of extra ammonia by improving control close to process constraints.’
• Burrup Fertilisers Pty Ltd, who reported: ‘The cost estimation and payback calculations confirm that the payback period was within one year which will translate to annual energy savings of approximately 96,167 GJ. There is also an annual production increase of 3083 MT of ammonia, at an implementation cost of just over $300,000, payback period less than one year. The final scopes of works and implementation details of the project are currently in the development stages.’

Minimise heat loss from steam generation processes

One of the most common processes in industrial chemical plants is distillation to separate chemical mixtures. Significant energy is used in this chemical separation processes because large quantities of steam need to be generated. A substantial quantity of energy can be lost as heat through the production and distribution of steam requiring more energy to maintain boiler temperatures. Inefficient distillation and steam generation systems can also increase air-conditioning cooling loads.

Thermal insulation of pipes and taps and the replacement of defective steam traps are effective cost-saving measures in the distribution of steam. The amount of energy involved should also provide a strong incentive for minimising heat loss from boiler systems by insulating boiler valves, steam and condensate return pipes, and storage units.

Improve the efficiency of existing equipment

Motors systems are widely used in the chemicals sector to drive pumps, fans and air compressors. Because of their extensive use, they provide excellent opportunities for energy savings. It is also possible to cost effectively improve the energy efficiency of boilers and steam systems, as well as lighting and HVAC systems.  The use of variable speed drives (VSD) can in some cases result in up to 50% energy savings with a three-year payback.¹

Optimising these technical systems, when coupled with best practice motor management, can generally deliver energy savings of between 30 to 60% cost effectively.²

See the Motors and Motor Systems, Process Heat, Boilers and Steam Systems and HVAC pages on the EEX website.

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Maintain existing equipment

A large proportion of energy used by chemical companies is related to the operation of furnaces and boilers. The efficient use of this equipment depends on good control and regular maintenance to reduce energy wastage in steam distribution. Key maintenance tasks include:

• Check insulation regularly – Checking insulation regularly and taking action to correct any inefficiencies can generate energy and cost savings of up to 5%. ¹
• Steam distribution systems are prone to leaks, which cost money – It is important to have a regular maintenance program of leak checking and repair, tackling the largest leaks first. Look for wisps of steam leaking from faulty steam traps, pipework flanges and joints. Leaks are easily detected and even small leaks can waste a lot of steam, so it is important to locate and repair them promptly.
• Ensure maintenance on boilers and heating systems is undertaken regularly – Dirty fans, filters and other components increase running costs and the risk of system breakdown. A poorly maintained boiler can use 10% more fuel than a well maintained one.
• Regular checks of compressed air systems and pro-active maintenance to identify and fix leaks will save energy – For instance, a chemical company in South Wales, UK, saved 50% on its compressed air energy costs by implementing a six-monthly leak detection and repair program.² This could be considered an extreme case, but it illustrates the value of checking regularly for leaks.
• Carry out regular maintenance – Carrying out regular maintenance on motors that drive pumps and fans can reduce energy consumption by as much as 10%.

Improve heat and power recovery

The use of heat recovery is very common in the chemicals industry. Many of the processes used in the industry require extreme temperatures and often need rapid changes in temperature.

Combined heat and power recovery technologies offer significant potential to improve the energy efficiency of existing processes at chemical and plastics plants.

Some examples of opportunities in this area are outlined below.

Install more effective heat exchangers

A theoretical study by the US Department of Energy¹ identified significant potential to improve the degree to which heat exchangers could recover more heat and energy from chemical processes.

Recent innovations in the construction of heat exchangers has enabled heat to be recovered from processes that were previously too extreme to deal with, such as very high temperatures and pressures, and chemically hazardous environments.

This has enabled more heat to effectively be captured and utilised in processes such as the manufacture of nitric acid or sodium hydroxide (caustic soda). ²

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Invest in cogeneration

Energy assessments of the chemicals sector have shown the potential for significant energy savings from investing in cogeneration. Studies in the US chemicals sector have found that combined heat and power systems, such as cogeneration, could enable a 44% reduction in greenhouse gas emissions. ¹

In Australia, Qenos has invested $45 million in cogeneration technology at its olefins site at Altona. This facility will meet Qenos’s electricity demand at that plant and will be capable of producing over a third of its steam requirements.  ² This builds on Qenos’s company-wide efforts since 1995, which have reduced greenhouse gas emissions by 40%, largely through a focus on energy efficiency.

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Recover waste heat and ensure boilers have condensate return

Energy and water loss can be minimised by using steam traps, which collect condensed water and return it to the boiler. This saves water and helps to conserve the heat of the water in the boiler, because the returned condensate is much hotter than feedwater and may not require treatment.

See the Process Heat, Boilers and Steam Systems technology page.

Implement process innovation and equipment upgrade

Energy analysis and best practice case studies demonstrate that significant savings can be achieved through innovations in chemical manufacturing processes and upgrades to more energy efficient equipment.  ¹

Some examples of opportunities in this area are outlined below.

Upgrade equipment to improve process efficiency

It is possible to significantly improve the overall energy efficiency of chemical and polymer processes through upgrading existing plant equipment. ¹

Steam cracking for olefin production is the most energy consuming process in the chemicals industry, but significant energy reductions are possible. The use of state-of-the-art technologies, such as improved furnace and cracking tube materials and cogeneration using furnace exhaust, can save as much as 20% of total energy.

The remainder of the energy is used for separation of the ethylene product, typically by low-temperature distillation and compression. Up to 15% total energy can be saved in this process by improved separation and compression techniques, such as absorption technologies for separation. Catalytic cracking also offers the potential for reduced energy use, with a saving of up to 20% of total energy.  ²

Consider alternatives to steam distillation

One of the most energy-intensive operations in the chemical industry is distillation separation. Most of the external energy and heat loss in distillation units occur in condensers, which are usually cooled by water or air. In many of the processes, a relatively few distillation columns and heat exchangers are responsible for the bulk of energy and heat losses. These losses could be minimised by improved heat integration, such as cooling the condensers with other process streams or by using waste heat to raise steam.

Another approach is to use alternative separation technologies such as reactive distillation and membrane separation: ¹

• Reactive distillation ²  is a process in which the separation of the product from the reaction mixture does not need a discrete distillation step, thereby saving energy (for heating) and materials. Product conversion can be increased as a result of the continuous removal of reaction products from the reactive zone.
• Certain mixtures of chemicals cannot be separated beyond a certain point by standard distillation processes and must undergo extraction. Liquid membranes offer an alternative to liquid-liquid extraction, and use much less energy. This technology can be used to separate both aqueous and organic mixtures. As an example, in separating a mixture of isopropyl alcohol and water, membrane separation uses 60% less fuel than liquid-liquid extraction. ³

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Utilise solar thermal systems for water heating

Solar water heating is well suited to help save energy by preheating boiler feedwater in steam boilers for a wide range of chemical and plastic manufacturing plants. Boiler feed can be heated in solar panels up to 80ºC before being fed to the boiler.

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Purchase and replace equipment with more energy efficient models

It is worth analysing whether there have been innovations in the core equipment used by your business. Over time, innovations often occur that substantially improve the efficiency of equipment compared to when you made your original purchase.¹

For example, polystyrene manufacturer Andpak (Aust) Pty Ltd based in Sunraysia, Victoria, has reduced energy use by 60% while also increasing production by more than 40%, through investment in more efficient moulding machines.  The new moulding machines require significantly less steam than other technologies, requiring less energy to run².

Significant energy efficiency improvements can be achieved through the upgrading and replacement of many types of equipment and ensuring new equipment is correctly sized such as motors, pumps and fans, compressed air and lighting.

To see examples of energy efficiency opportunities in specific technologies, go to the Technologies section of the EEX website. 

For more information

• Carbon Solutions –Victorian Energy Efficiency and Carbon Reduction Program 2011 (Opens in a new window)
  • Equilibrium and PACIA
  • PDF 478 KB

  This resource developed by PACIA outlines the results from energy and carbon emission assessments conducted at nine different plastics and chemical sites. The study highlighted key opportunities for emission abatement in areas such as compressed air systems, pumps, motors, chillers, steam systems and lighting. The resource also includes tips on how to sell the business case on energy efficiency and build it into management systems.

• How to purchase new compressed air equipment
  • UK Carbon Trust
  • Website

  This  guide from the UK Carbon Trust provides guidance on the questions to ask when purchasing new compressed air equipment.

  It includes information on different types of compressors, tips on how to analyse demand and select appropriate sizing and details on different control and treatment systems.

  Note, this publication is free to access, but users must register first.

Design chemical and plastic products to enable energy efficiency

More than 85% of the outputs from the Australian chemicals and plastics sector are inputs to other sectors in the Australian economy. ¹

Chemical processes underpin all industrial processes and affect the energy used in manufacturing most materials. There is a significant business opportunity for the chemicals sector to increase profits, market share and build customer loyalty through designing greener and more efficient chemical products, materials and services. Methods include:

• making the same products in new ways that use less energy
• creating corrosion-resistant chemical materials and metal products
• using lightweight plastic parts to improve fuel efficiency for transport vehicles
• reducing energy use in the manufacture and transport of packaging. The growing use of plastics means that today’s packaging is up to 80% lighter than the packaging of 1990 ²
• new and novel catalysts developed by the chemical industry reduce the need for energy intensive chemical processes, e.g. novel catalysts enabling second generation biofuels ³
• materials for the construction industry that can significantly reduce energy use for building heating and cooling requirements, e.g. smart insulation materials, low emissivity windows, lighter materials, composites in construction and fittings. A McKinsey Global Institute study showed that the greenhouse gas emissions saved from the use of insulating materials is twice the total amount of greenhouse gas emissions produced by the chemicals sector ⁴
• improving the conversion efficiency and battery storage of renewable energy sources
• improving the materials used in the manufacture of wind turbines, solar panels, installation equipment and piping for geothermal systems
• extending the shelf-life of goods and other perishables in food production and storage.