Chemicals sector

Introducing energy saving opportunities for business

Chemicals sector

Contents

2

Energy consumption 03

Energy saving opportunities 05

Processes and process control 05

Furnaces, boilers and steam distribution 06

Motors 09

Compressed air 11

Process operations and equipment 13

Distillation 13

Evaporation 14

Drying 14

Refrigeration 15

Industrial gases 16

Cooling water 16

Industrial buildings 17

Energy management 21

Government energy-related regulation 23

Action checklist 24

Further services 26

The Carbon Trust acknowledges the kind help of the Chemical IndustriesAssociation and the Chemical Industries Broking and Trading Agency in thepreparation of this publication.

Reducing energy use makes perfect business sense; it saves money, enhances corporate reputation and helps everyone in the fight against climate change.

The Carbon Trust provides simple, effective advice to help businesses take action to reduce carbon emissions, and the simplest way to do this is to use energy more efficiently.

This overview introduces the main energy saving opportunities for businesses within the chemicals sector and demonstrates how simple actions can save energy, cut costs and increase profit margins.

Energy consumption

The UK chemicals industry manufactures nearly 95,000 different products on about 8,600 sites. These sites range from large, continuously operated units producing huge outputs of bulk chemicals to small, batch-operating, speciality chemicals sites producing small amounts of high-value products. The chemicals industry is the largest industrial user of energy in the UK, spending around £4 billion on energy and hydrocarbon feedstock in 2010. This represents around 30% of total industrial energy costs.

The extent of energy usage varies considerably within sub-sectors. For example, in the chlor-alkali sub-sector, energy represents as much as 50% of manufacturing costs, while a pharmaceutical business might expect energy costs to be under 5%.

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Figure 1 Industry breakdown

Refined petroleum products

Industrial gases

Dyes and pigments

Other inorganic basic chemicals

Other organic basic chemicals

Fertilizers and nitrogen compounds

Plastics in primary forms

Synthetic rubber in primary forms

Pesticides and other agro-chemical products

Paints, varnishes and similar coatings, printing ink and mastics

Basic pharmaceutical products

Pharmaceutical preparations

Soap and detergents

Perfumes and toilet preparations

Explosives

Glues and gelatines

Essential oils

Photographic chemical material

Prepared unrecorded media

Other chemical products

Man-made fibres

Why save energy?

Some people working in the chemicals manufacturing sector believe that energy bills are a static overhead cost. This is a myth. By taking a positive and proactive approach to energy efficiency, businesses can control and reduce their energy spend. All manufacturing companies are under pressure to cut costs and increase profits, and saving energy is one good way to meet this goal. There are many energyintensive sites which have changed their businesses to be more efficient in the last decade, and they continue to improve. Their success demonstrates that it is possible to reduce carbon emissions and save on energy costs.

Furthermore, by participating in Climate Change Agreements (CCAs), most of the chemicals industry is committed to achieving targets for energy saving.

Saving energy also improves environmental performance. It can help achieve ISO14001 and, by cutting carbon emissions and helping to combat climate change, demonstrates a degree of corporate social responsibility to stakeholders and a commitment to an overall sustainable approach.

Managers in the chemicals sector are often concerned about compromising the quality or consistency of their product by making changes to save energy. But by taking action, this energy intensive industry can reduce its consumption – and its costs – with no detrimental impact on the product.

Who should read this overview?

This overview is for business leaders in the chemicals sector. It lists straightforward, low-cost measures as well as investment opportunities, which might require specialist advice and assistance.

More information about other industrial sub-sectors and further energy saving advice is available from the Carbon Trust.

The chemicals industry is the largest industrial user of energy in the UK.

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Energy saving opportunities

Processes and process control

Typically, better process control can save between 5 and 15% of a company’s process energy.

It is crucial for chemicals manufacturers to meet product specifications and quality is a particular concern in this sector. Managers at chemicals sites can be concerned about their processes – and changing them can seem risky.

However, analysis and improvement to the production processes does not necessarily mean compromising the output. Energy savings mean cost savings, and with the right approach, these can be significant.

The first step to good control is to look at the product and see how the processes work together to create it. There may be ways to improve or tighten the processes without compromising the product and ensuring consistency.

One of the key ways to improve a process is to improve its control. This is often automated and can be very complex, but there are some straightforward areas to inspect.

Are products being over-processed?If plants are manually controlled, it is common practice for them to be operated well within the operators’ comfort margin. This ensures that product specification is met, while minimising the need for frequent manual intervention. However, this practice can result in the over-purification or over-specification of the product, which in turn results in excessive energy consumption. Automating simple tasks can yield significant energy savings because process operators are less effective at routine control tasks than a control system is – even the best operator cannot monitor the plant every second and decide if some parameters need to be adjusted.

Identify any excessive or variable energy consumptionIt should be possible to analyse the energy use in terms of the throughput. Excluding the baseload, find out if the energy use per unit produced (for example, kWh per tonne) is broadly consistent. If it is not, then improving plant control can save energy. A poorly controlled plant is almost always a major cause of extravagant energy consumption and will result in an increase in other manufacturing costs. If a problem is identified, a control engineer will be able to tune and improve existing control systems to reduce energy consumption.

Check controls have not been switched from automatic to manualSwitching controls from automatic to manual frequently occurs on industrial sites and is a very inefficient method of operation. Investigate why the control system is being operated this way as operators usually have a good reason for switching to manual. It could be that the controller is not working properly because of poor measurement, it may be wrongly specified or it may not be tuned correctly. A control engineer should be able to rectify the problem and restore automatic control.

Check for unreliable or inadequate measurementsThe control system will not work properly if its measurements are inaccurate. Poor measurement and resulting poor control will waste energy, result in poor product and cost your company money. Measurement errors can occur for a variety of reasons, for example, the measuring device may have been badly chosen for the duty involved or there may be a poor signal from the measuring device to the controller. These faults can be investigated by a control engineer and can be rectified easily, leading to energy savings. This highlights the need for the routine checking, maintenance and calibration of control sensors.

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Furnaces, boilers and steam distribution

In most chemicals companies a large proportion of energy is used by furnaces and boilers. Their efficient use depends on good control and regular maintenance.

In some cases, the performance of furnaces and boilers can be further enhanced by using ‘add-on’ equipment.

Inefficiencies in steam distribution are another source of energy wastage at a site. Again, good maintenance is the key to efficient operation.

Furnaces and boilers

Check air/fuel ratioThe air/fuel ratio of the burners in a furnace or boiler is important. The wrong ratio can result in excessive fuel consumption and poor combustion, which could potentially lead to illegal emissions. The ratio may be wrong because of poor control, a poor set-up or mechanical problems with the burner. Any problems with air/fuel ratio will be apparent by monitoring the furnace flue gas. Yellow or smoky flames generally indicate inefficiency, so make sure that all flames burn blue and clear. Ask a maintenance technician to check air/fuel ratios.

Use the correct type of burnerThe correct choice of burner is important as there are many types that could be used for a particular operation, but some are more energy efficient than others. Expert advice should be sought when selecting burners to ensure they are energy efficient and the most appropriate for the purpose.

Improve insulationEfficiency can be increased by improving insulation on a furnace or boiler and surrounding equipment. Insulation may be damaged or missing or, if it is an old furnace or boiler, the thickness could be inadequate. Carry out an insulation survey either in-house or using a consultant. Repair or replace any damaged or missing insulation.

Consider air pre-heatingHeat can be recovered from furnace waste gases using a heat exchanger. This heat can then be used to pre-heat the combustion air, which is a useful method of reducing energy use in a boiler or furnace. However, air has to be heated by 20ºC to get a 1% improvement in efficiency and there is a maximum temperature of around 50ºC to which the air can be raised.

Consider installing variable speed fansFans are used to promote the flow of combustion air and exhaust gases. Traditionally, this is controlled by dampers interrupting the airflow from a fan working at full load. Savings can be made by installing variable speed fans to vary the airflow rather than using the dampers. This is a much more energy efficient solution which also involves fewer moving parts and, therefore, tends to have lower maintenance costs.

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Case studySteam boiler house improvements

A manufacturing company fitted an economiser and advanced boiler control to improve boiler performance. This resulted in:

• Annual cost savings of around £55,800 for an investment of around £55,300.

• Annual energy savings of around 7,000MWh, equivalent to carbon savings of nearly 1,500 tonnes/year.

• Boiler efficiency increased by 9.8%.

• Payback period of less than a year.

Are steam/hot water boilers working efficiently?Boiler operation efficiency can be improved by making sure the boiler is operating at optimum conditions through good control and by regular maintenance and servicing. Fouling of heat transfer surfaces should be kept in check as this leads to inefficiency and energy losses. Equipment suppliers will be able to specify the recommended frequency of boiler services.

Review blowdown operationSavings can be made by reviewing blowdown operation. When water is evaporated in a boiler, the concentration of dissolved and suspended solids increases in the remaining water. To maintain these solids below levels at which they would cause problems, water has to be removed from the boiler periodically in an operation called ‘blowdown’. Typically between 1% and 5% of energy input to the boiler is lost in blowdown operations. Savings can be made by switching to automatic blowdown as manual operation tends to use more blowdown than is actually required to maintain solids within safe concentrations. Seek advice to assess whether a switch to automatic blowdown is viable.

Consider using economisersAn economiser is a heat exchanger that is attached to the flue-gas outlet and transfers heat from the hot flue gas to the water being fed into the boiler. This means that less energy is required to heat the water in the boiler. Therefore, fitting economisers is an excellent way to reduce the loss of heat and save energy.

Invest in a new boilerIf the boiler has been in use for a number of years it may be worth switching to a new, more efficient boiler, possibly of a different design. A boiler manufacturer or a consultant will be able to advise on the viability of boiler replacement.

For further advice on boilers and heat distribution download the following publications:

Low temperature hot water boilers technology overview (CTV051).

Steam and high temperature how water boilers technology overview (CTV052).

Consider low-carbon energy suppliesExamples of low-carbon energy supplies include combined heat and power and renewables.

Combined heat and power (CHP) plant offers simultaneous generation of usable heat and power in a single process. Because of this simultaneous generation, the use of CHP can have significant cost and environmental benefits under the right circumstances. If considering installing CHP, make sure that it will be economic throughout its lifetime, and that the business has appropriate resource to maintain the plant.

Renewable energy sources may also be appropriate for the site, and installations include wind turbines or biomass boilers. The Carbon Trust’s Renewable energy sources overview (CTV010) has more information.

When considering any instalment project, an expert or consultant should be employed. He or she can review the viability of CHP or renewables and identify the most appropriate solution.

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Case studyCHP at a pharmaceutical company

Two CHP units at Pfizer’s site at Sandwich in Kent resulted in:

• Over 20% savings on energy costs.

• Provision of 80% of the site’s off-peak electricity requirements and 50% of its heat requirements from waste-heat recovery.

• Four-year payback period on both installations.

• Savings in line with internal projections and expectations.

Fact:A UK survey of 300 boilers over 100 sites showed that average savings of 7% are possible by improving the efficiency of steam generation. Further savings could also be made by applying energy efficiency measures to steam distribution.

Steam distribution

Check for leaksSteam is an expensive utility that is difficult to contain. If processes use steam and involve any sort of distribution network, then they will most probably have leaks, which cost money.

It is important to have a regular programme of leak checking and repair, tackling the largest ones 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 find and repair them promptly.

Ensure adequate insulationAll steam pipework should be insulated to prevent heat losses. The current lagging may not be the correct thickness, some lagging may be missing or parts of the lagging may be damaged or waterlogged. By checking insulation regularly and taking corrective action, energy and cost savings of up to 5% can be made.

Identify redundant pipeworkOn older sites some of the steam distribution system may have become redundant. If this is the case, it is important that the redundant part is sealed off as near to the boiler as possible. Otherwise, the resulting ‘dead leg’ can become a source of unnecessary heat losses.

Make sure that steam traps are working effectivelyIt is inevitable that some steam will condense in the distribution network. Steam traps, if they work correctly, remove this condensate from the system without significant losses of steam. However, a major source of steam loss is through ‘sticking’ steam traps. Therefore, steam traps should be checked as part of a regular distribution network survey so that corrective action can be taken if any are found to be defective.

Consider using condensateSteam condensate from the plant is a valuable source of heat and, where possible, should be captured within pipework and returned to the boiler, thereby reducing the energy load on the boiler as well as conserving water. For more information on this option, contact the Carbon Trust.

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Case studyInsulation jackets

At a chemical company in Teesside, two projects involving the fitting of insulation jackets to valves and flanges resulted in:

• Annual cost savings of £5,880.

• Annual energy savings of 590MWh.

• Carbon savings of 29 tonnes/year.

• Payback period of 1.6 years.

Tax incentives

Enhanced Capital Allowances (ECAs) are a straightforward way for a business to improve its cash flow through accelerated tax relief. The ECA scheme for energy-saving technologies encourages businesses to invest in energy saving plant or machinery specified on the Energy Technology List (ETL) which is managed by the Carbon Trust on behalf of Government.

The ECA scheme provides businesses with 100% first year tax relief on their qualifying capital expenditure. The ETL specifies the energy-saving technologies that are included in the ECA scheme. The scheme allows businesses to write off the whole cost of the equipment against taxable profits in the year of purchase.For further information please visit www.carbontrust.co.uk/eca or call the Carbon Trust on 0800 085 2005.

Motors

Motors are widely used in the chemicals sector to drive pumps, fans and other equipment. Because of their extensive use, motors are likely to provide excellent opportunities for energy savings.

Motors and drives are often overlooked in a business, and as a result, a large number of sites operate their motors inefficiently. In many cases, simple changes in working practice can reduce an organisation’s energy bill.

The Carbon Trust has several further publications with ideas for energy saving in motors and drives, and their use in pumps and fans.

Switch it offSignificant amounts of money and energy are wasted by motors being left running when not required. This is sometimes because staff falsely believe they should be left running for a specific reason. Challenging these assumptions, and putting in place a procedure to switch off the motor, pump or fan at the end of operation can pay dividends. An alternative solution would be to use a timer or automatic sensor to turn the pump or fan off.

Reduce the pumping loadInvestigate the potential for reducing pumping load because the volume of liquid used in a process or cooling water may be unnecessarily high. In the same way, there may be opportunities to reduce the fan load by reducing the volume of fresh air fed into buildings or reducing the gas flows used in various process operations.

Maintain motor systemsCarrying out regular maintenance on motors used to drive pumps and fans can reduce energy consumption by as much as 10%. Maintenance programmes should consist of lubrication schedules, cleaning, belt tensioning and alignment checks. It is also worth considering using predictive maintenance techniques that can indicate in advance when parts will need replacing. A motor supplier will be able to provide you with more details on recommended maintenance checks.

Check for correct sizingMost process motors in the chemicals sector operate at part load, even though motors operate most efficiently at full load. There are usually good reasons for part-load operation, such as a requirement, or a perceived need, to have spare capacity. To maximise efficiency, however, a smaller motor should be used.

Compare the details on the motor rating plate with the actual rating required by the equipment that the motor is driving. In many cases, motors are oversized by 20% or more. For example, an application might require a motor rated at only 7.5kW, but has been supplied with a motor that is 11kW. Consider replacing with smaller, higher efficiency motors where possible (see next page).

If the motor is very lightly loaded (<40%) and cannot be changed, it may be possible to run the motor continually in a different connection mode that could result in energy savings of between 5 and 10%. Consult a motor supplier regarding connection modes. They will be able to assess the business’s needs and advise.

Sizing is also an important consideration for pump selection. In cases where extra capacity may be required, back-up pumps can be installed and switched on when required. Therefore, to realise energy savings, the size of a pump should be based on the realistic maximum pump loading required.

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Did you know?A fully loaded motor consumes its own initial cost in electricity in 30 to 40 days of continuous running. Always consider the whole life-cycle costs before buying a new motor. Make sure that calculations take into account the commissioning, installing and purchasing costs, plus running costs (that is energy costs and maintenance).

Replacing failed motors with higher efficiency motors (HEMs)Higher efficiency motors (HEMs) are between 3% and 4% more efficient than other motors. Note that it is usually more cost-effective to replace motors than to rewind them, although for larger motors operating intermittently, rewinding may still be the best option. A quick calculation of replacement and operational costs will show the best option.

Develop a motor management policyMotor management policies are agreed documents that give details of motor use across a site and present a strategy for replacing motors with higher efficiency equipment. Written policies form a vital part of all effective energy management campaigns on industrial sites.

There are more motors per square metre on chemicals sites than in any other industry.

Consider installing variable speed drives (VSDs)A VSD is an electronic device that controls the characteristics of a motor’s electrical supply. They are able to control the speed and torque of a motor, achieving a better match with the process requirements of the machine it is driving and operating it more often in its most efficient regime.

Fans and pumps are usually the best applications for a VSD. This is because these applications are the most likely to have variable demand.

The installation of VSDs is easily justified when there is a variable load because of the reduced running costs of the motor.

For further advice on motors and drives download our Motors and drives technology overview (CTV048).

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Fact:– Reducing the motor speed by 20% reduces the

power requirement by about 50% and therefore greater energy savings can be made.

Compressed air

Compressed air is a very expensive form of energy. It is also a major source of energy wastage because of the tendency for distribution systems to leak and because of the inefficient way it is often used.

Switch offWatch what happens to air-consuming equipment when there is no production, such as between production batches for fine chemical and pharmaceutical manufacture. Is equipment left working when it isn’t required?

Instigate switch-off routines and include them in a compressed air usage policy. Consider whether it is appropriate to do this for each process and, if so, work out when they should be implemented. Ask if switch off can be automated using time-operated solenoid valves or interlocks that allow a compressed air line to operate only if another piece of equipment is already running. Another, more complex option would be to use sensors that detect when a part is present on a conveyor, for example, to ensure that compressed air valves are operated as and when required. These systems can be straightforward to install and more than pay for their cost in energy savings. Contact an equipment supplier for more information.

An idling compressor can still use 40% of its full load

Eliminate unnecessary useCheck for unnecessary use of compressed air, for example, ask if compressed air is used to clean equipment instead of an alternative method that would be more cost effective. To guard against this, write a usage policy that details acceptable uses for compressed air, and suggests safe and easy alternatives. Make sure that equipment or tools are provided for the alternative methods.

Reduce leaksThe biggest losses in a compressed air system will be due to leaks.

There are three main ways to identify leaks:

• Listen – run the compressor without using any air tools or equipment. Make sure that there is as little background noise as possible and then walk slowly around the system listening for hissing or rasping sounds. Check all joints, flanges and valves carefully.

• Look – make up a simple solution of soapy water. Run the system without using air tools or equipment. Apply the solution to all pipework and then look to see where the soapy water bubbles up.

• Detect – hire or purchase ultrasonic leak detection equipment from a compressed air system supplier. Using ultrasonic equipment is the most accurate way to check for leaks.

Mark all leaks on a plan of the system. Before attempting any repair work, make sure that the system is de-pressurised. Small leaks can be repaired on-site, but contact the equipment supplier before tackling larger leaks. Consult a supplier if you are in any doubt about how to proceed.

Try a ‘no-load’ test: running the compressed air system at quiet times, when there is no equipment to need it. This will help identify leaks more easily and, if no air is being used in the system, will show how much air is being lost through leaks. Also check the distribution system to see if there are any redundant lines that are still ‘live’. If any are found, they should be blanked off. When leaks have been identified, repair the largest first.

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Did you know?– Compressed air leaking through a single 3mm

hole could cost you around £4,000 per year, depending on use and pressure.

Regulate pressurePressure should always be regulated to the correct level for end use devices. Compare the manufacturer’s stated requirements and the actual pressure the devices are using. If the requirement is less, it may be worthwhile fitting a pressure regulator locally to the device to make sure that its air is maintained at the right level.

A check of the devices using compressed air may show that a small number of the applications use a very high pressure, while the majority could operate with a much lower pressure. If this is the case, it might be worth having a separate compressor for the high users, and use the general compressor set at a low pressure to save energy.

Rationalise compressor useFurther savings can be made by reducing the number of air compressors in operation. For example, a number of compressors operating at part load could be replaced by fewer compressors operating at full load. This takes advantage of the fact that compressors operate more efficiently at near or full capacity. It is particularly worth considering this option if reductions in your compressed air usage have already been made through the energy saving actions suggested above.

For further advice please download our Compressed air technology overview (CTV050).

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Case studyLeak detection and repair programme halves generating costs

A chemicals company in South Wales saved 50% on the cost of generating compressed air by implementing a six-monthly leak detection and repair programme. The first survey detected 412 leaks, equivalent to an annual loss of £66,500. Fixing the majority of these leaks led to a substantial saving in electricity costs and made a valuable contribution to the company’s Climate Change Agreement target for carbon reduction. The company used a hand-held ultrasonic leak detector, and each survey was followed by a round of repairs in which typically 75% of leaks were corrected at minimal cost.

Safety firstOne of its primary uses in the chemicals sector is the actuation of control valves especially in areas where there is a high fire or explosion risk. When used in this way, it is essential that the compressed air supply is maintained.

Process operations and equipment

There are significant savings to be made in improving the energy performance of large process equipment.

As with all process plant, process control should ensure optimum conditions for operation. Some of the more common process operations in the chemicals sector are looked at in more detail below. Note that many will involve some capital expenditure and when considering any changes to plant, a technical expert should be consulted (see grey box).

Distillation

The main energy savings will be made from ensuring the distillation is being carried out under optimum conditions and that the products are not being over-purified.

Optimise your distillation columnSavings can be made by using more efficient distillation trays or column packing. Distillation columns should already be well integrated and there will probably be little scope for waste heat recovery. However, there are a number of modifications that can be made to the column to improve thermodynamic efficiency. If the process involves separating several components, then there are many ways to improve distillation efficiency through changing distillation configurations. In some cases, there are alternatives to distillation such as pervaporation and crystallisation which are less energy intensive.

Take note: These measures are likely to be significant undertakings, requiring capital expenditure and the services of a technical expert. A good time to consider these issues is during systems redesign.

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Tip– A check should be made of all process equipment

to ensure all hot surfaces are lagged, and that any missing or damaged lagging is replaced.

Seek expert adviceAdvice from an in-house technical expert or external plant designer should be sought before any changes to processes or plant are made. An expert can help select the most appropriate equipment and applications to maximise energy – and cost – savings.

Evaporation

Evaporation removes water and concentrates a feed liquid. The main energy input is to increase the temperature of the water to its boiling point and then supply latent heat to convert the water to steam.

Reduce water inputThe primary way of reducing energy use is to reduce the load by minimising the amount of water added to the feed liquid upstream. The implications of increasing feed stream concentration upstream of the evaporator would need to be considered.

Consider changes to the evaporatorSome energy saving measures may require design changes. These may include looking at ways to recover the heat of the evaporated water, such as using a simple condenser if there is a use for the waste heat, or a mechanical vapour compression to deliver heat to the evaporator. Another possibility is to use multiple-effect evaporation, which is much more efficient than single-stage evaporation. Multiple-effect evaporation is carried out in several stages, with each stage being at a lower pressure than the previous stage. The steam from one stage is then used as the heat source for the next.

Drying

Drying is the removal of water from a solid product by the addition of heat energy.

Consider making process changes upstreamBy reducing the water content of the solid before it is dried, the load on the dryer will be reduced. This can be achieved by process changes being made upstream or by using mechanical means that usually require less energy than heat-based techniques.

Control drying operationTo maximise energy savings, ensure that the drying operation is well controlled and maintained. Hot surfaces should have adequate lagging.

Consider improvements in dryer designThere is scope for further energy efficiency improvements in some types of dryer, for example, by optimising air input and air-flow patterns within the dryer. These improvements can lead to a reduction in air use and consequently energy use. Support from a technical specialist or manufacturer will be needed to assess whether these changes can be made without affecting drying quality.

Recover waste heatThere may be opportunities with some types of dryer to recover waste heat from the air leaving the dryer and using it to pre-heat the inlet air or provide heating elsewhere on the plant. This will not be suitable for every business, but a consultant can assess the opportunities.

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Refrigeration

Refrigeration is an energy intensive operation and its use should be carefully monitored. Maintenance of the refrigeration system is important. It may be necessary to use refrigeration engineers.

Identify and repair any leaksMost large refrigeration systems have sight glasses where the refrigerant can be viewed. If bubbles can be seen in the refrigerant when the system is in a stable operation, it usually indicates that there is a refrigerant leak in the system. As refrigerant levels drop, the system will operate less efficiently and may not achieve the desired cooling level.

Therefore, refrigerant leaks can lead to inefficient operation and should be avoided for environmental reasons. Portable or permanent leak detectors provide low-cost ways of detecting leaks early and allowing repairs to be carried out.

For further information, see the Carbon Trust’s Refrigeration technology guide (CTG046).

Consider purging the systemInfiltration of air into the refrigeration system through pipework or during maintenance operations can also reduce efficiency. Refrigeration systems should be regularly purged, either manually or by using automatic air purger units, which tend to be more effective. Contact a refrigeration supplier for more information.

Ensure adequate insulationInsulation on pipework should be in good condition to prevent unnecessary heat gains. Replace insulation where it is damaged or missing. Waterlogged insulation is a considerable source of heat gain and the source of the waterlogging should be identified and repaired.

Consider the timing of operationsCan process operations be carried out at night or in the winter months when less cooling will be required? Can some of the refrigeration load be handled by pre-cooling? This is more likely in the winter when, in many cases, ambient air temperature may be lower than required chilled-water temperatures.

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Industrial gases

The production and storage of industrial gases such as oxygen, nitrogen and argon is highly energy intensive.

Consider industrial gas managementIndustrial gas use should be carefully managed to maximise both energy and cost savings. Measure the use of industrial gases carefully and review their usage to identify potential for further reductions. Through regular monitoring any unexplained high levels of use can be identified and action taken to find out why they are occurring.

Review purity of gasMany companies use industrial gases that are much purer than actually required. The higher the purity, the more energy is used to produce it. It may be possible to reduce energy requirements by relaxing the purity of the industrial gas produced, assuming that this less pure gas continues to meet the requirements of the process.

Consider utilising waste gasIf the plant produces gas internally, waste gas streams may be useful elsewhere in the plant, for example, waste gas from nitrogen production is rich in oxygen and can be used as part of the combustion gas for a furnace or boiler.

Look at alternativesAgain, if the plant produces its own industrial gas, consider if there are options for alternative production strategies and energy saving measures. It may be economical to use an alternative method to generate industrial gas or a smaller and potentially more economical plant could be used. Consider speaking to a consultant to examine the viability of alternative strategies.

Cooling water

Minimise the flow of cooling waterMost process operations use cooling water, which uses energy to pump it around the cooling circuit. In many cases, cooling towers are used to cool the water but, in others, refrigeration chillers are used that consume considerable amounts of energy. Most plant have energy saving features such as minimising the flow of cooling water and by not cooling to a temperature lower than is actually required. Further savings can be made by operating energy efficient pumping measures as described in the Motors section of this guide.

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Did you know?

Waste heat recoveryMany industrial processes produce waste heat which can be recovered using a heat exchanger. This heat can then be used to heat other parts of the process thereby reducing the need to burn fuel. The key is to identify where the heat can be used. A technical expert or contractor can be employed to carry out a short survey to identify sources and potential uses of waste heat.

Industrial buildings

For most businesses in the chemicals manufacturing sector, energy use in buildings is likely to form a small part of the overall energy use of the site. However, it is an important area to look at because the potential for savings may be high.

Opportunities in industrial buildings include systems such as heating, ventilation and air conditioning. Lighting, boilers and building fabric are also worth investigating.

Industrial buildings typically require large areas for storage and production, often having high ceilings and high ventilation rates. Usually there is further ‘social’ space in areas such as offices, and in many cases the buildings will include canteens or kitchens. With such a range of activities and characteristics, industrial buildings usually have complex energy requirements.

Heating

Keeping a workplace at a comfortable temperature is essential for a happy workforce and may be important for some industrial processes. To save money, use simple time and temperature controls, gain an understanding of the building heating system and raise staff awareness about heating costs.

Take control of the heating systemHeating control systems are sometimes adjusted in response to a change in weather conditions or a change in shift patterns. To manage a heating system effectively and save up to 10% of costs, focus on these simple measures:

• Check thermostats regularly and set to the recommended temperature (19-21ºC for site offices, 16-19ºC for workshops and 10-12ºC for stores). Doing this will save 8% for each 1ºC reduction in temperature.

• Check all timer switches regularly – make sure that the heating is off when the building is unoccupied.

• Raise awareness – discuss the costs of heating at team meetings and encourage people not to leave doors and windows open when the heating is on. Adjust the thermostats instead.

Use a de-stratification fanThe temperature of a building will be highest nearest the roof, so consider using a de-stratification fan to recirculate this heat to lower levels.

Radiant heatingFactories and warehouses can easily lose heat because of high ceilings, extractor ventilation systems and frequently used delivery doors.

If a site has convective ‘blown air’ heaters, then consideration should be given to changing to radiant heating. This type of heating reduces heat losses and improves comfort because people and surfaces are heated directly as opposed to convective heating systems that simply warm the air. Correct positioning of the heater is important – it should be directly in line with the person/object requiring the heat.

Improve boiler efficiencyMany chemical manufacturing sites use boilers for space heating. Improving their efficiency through insulation, maintenance and control can provide significant energy and cost savings. See page 5 for some ideas, but also contact the Carbon Trust for publications on both steam and hot water boilers.

Ventilation

Ventilation can often be excessive. However, when optimised, it can increase staff comfort and save money. Most of the energy saving actions suggested here cost very little – or nothing at all.

Turn off unnecessary ventilationCheck that local extraction fans are not left running unnecessarily, either outside of production hours or during long breaks between shifts. If the fans cannot be seen or heard, then air movement can be detected very simply using thin strips of tissue paper or with a child’s bubble maker. Ensure that ventilation is turned off when it is not needed either by raising staff awareness or by fitting simple automatic controls.

Consider interlocked controlsAutomatic controls can be in the form of timers, occupancy sensors or controls linked to machinery (interlocked controls). Using automatic controls to replace a previously manual action can result in significant energy savings.

17Chemicals sector

Localise ventilationPut process plant that needs local extractor ventilation in a special area and introduce fresh untreated air close to the plant and extractor. This reduces costs by preventing heated or cooled air being drawn from surrounding areas.

Fit and maintain shuttersAll fans should have back-draught shutters or dampers to prevent air blowing through them when not in use. Fit shutters or dampers and ensure that they are kept clean and in good working order.

Air conditioning

Energy consumption of air conditioning systems in the UK has an annual cost of £1,700 million. Air-conditioned buildings use about twice as much energy as naturally ventilated buildings – this energy is used to condition the air and to power pumps and fans to circulate it throughout the building.

In recent years there has been significant progress in the application of techniques that reduce the dependency on conventional air conditioning and move towards natural and passive ventilation, mixed-mode operation and low-energy cooling systems.

Ask if air conditioning is neededAir conditioning may well be necessary if the processes require a constant temperature or precise humidity control. However, if air conditioning is used for comfort cooling, there may be other options. Investigating appropriate ventilation and minimising heat gain may make air conditioning unnecessary.

There may be ways to reduce the temperature, for example, by limiting the time that equipment is on. Switch off lighting if there is sufficient daylight and use solar films or blinds to cut out direct sunlight that might be causing overheating. Open windows and doors to reduce overheating further.

Control it – temperatures and timesSettings on air conditioning units can be easily altered. Failure to put them back to their correct settings is a common oversight, so check temperature and time controls regularly. Look at operating patterns of the air conditioning chillers relative to outside conditions and check for excessive running. Temperatures should be comfortable and need to be appropriate for processes, but operation of an air conditioning system should be kept to a minimum where possible.

Review switch-on temperaturesMake sure that air conditioning is not set to come on until it is reasonably warm: a usual figure is 24ºC. Set a gap or ‘dead band’ between heating and air conditioning control temperatures of about 5ºC, so that heating will not be operating at the same time as air conditioning. This improves staff comfort, cuts operating costs and reduces wear and tear on both systems.

Stop relative humidity control – if possibleControlling relative humidity is very energy intensive and large savings can be made by discontinuing it. However, some processes do require a certain level of humidity and if this is the case, the minimum and maximum acceptable humidity levels should be kept as far apart as possible to reduce usage.

Take advantage of free coolingInvestigate ways which reduce the internal temperature at no cost, such as night cooling. This is especially effective where external temperatures are significantly cooler than the required internal temperature and operate by simply ventilating the building with fresh air. For information on these opportunities, refer to the Carbon Trust’s publication, Heating, ventilation and air conditioning (CTV046).

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Fact:Many companies could save 20% of their heating costs or as much as 4% of their total energy bill.

Building fabric

Many manufacturing industries do not set aside money to maintain their building fabric, that is, the walls, doors, windows and roofs of their premises. Investing in maintenance and insulation is almost always cost-effective. It can also increase the value of your property and, by providing a more comfortable working environment, boost staff morale.

Stop draughtsWhen not in use, keep factory and loading bay doors closed to prevent heat loss.

Separate heated offices or workspaces from unheated storage areas to reduce heat losses and improve comfort. A warm air curtain, PVC curtain or a swing door are all suitable partitions.

Repair broken or cracked windows as soon as possible and apply draught strips wherever draughts can be felt.

Separate warm from cool spacesFor doors that are used frequently, consider fitting one of the following:

• Air-locks.

• PVC curtains.

• Warm air curtains.

• High-speed, motorised doors.

The doors need to be sealed to the building fabric to prevent draughts and there should also be seals between the door and the frame. Avoid using doors at opposite sides of the factory at the same time because this will create through draughts.

Insulate roofs and wallsImproving loft and cavity-wall insulation is the single most cost-effective measure that can be made to the building fabric.

• If the structure allows, make sure that there is at least 200mm (8 inches) of loft insulation. Roofs made of single-skin, corrugated asbestos or corrugated iron can have heat losses 15 times that of a modern, well-insulated roof. Methods for insulating these types of roof include lining, over-spraying and under-spraying.

• Consider installing polycarbonate secondary glazing under rooflights – it can reduce heat losses by up to 50% and eliminates down-draughts.

• Insulate cavity walls – it can reduce heat loss by 70% or more.

19Chemicals sector

Energy Efficiency Financing:Investing in energy efficient equipment makes sound business and environmental sense, especially with the easy, affordable and flexible Energy Efficiency Financing scheme brought to you by Carbon Trust Implementation and Siemens Financial Services. To find out more visit www.energyefficiencyfinancing.co.uk

Lighting

Most companies spend little time considering how their sites are lit. Lighting can be a good starting point to reduce energy costs. Many of the actions cost nothing to implement and can get the workforce involved.

Switch off lightsLights switched on in the morning are often left on all day – even if they are not needed. Here are some simple ideas to ensure that lights in unoccupied areas are switched off, potentially saving 15% on lighting costs.

• Encourage people to turn off lights – use posters and team meetings to raise energy awareness and motivate people to turn off lights. Free posters and stickers can be ordered from the Carbon Trust.

• Make sure everyone knows where the light switches are – label light switches and make sure everyone knows which switch controls their light.

• Make sure that lights are switched off when the factory is closed – carry out a survey to find out if lights are turned off out of hours. Ask cleaning and security staff to turn off lights in unoccupied areas.

Make good use of natural lightMost people prefer to work in natural light and so interior lighting will be used less when adequate daylight is available. To make the best use of natural light try the following:

• Check how often and how well windows are cleaned; get the cleaner in more often if necessary.

• Check that any roof lights are being used effectively.

• Make sure window blinds are open in daylight hours, except when needed to reduce glare or solar gain.

• Move any objects that are obstructing windows.

• Review the location of people and if possible move them closer to natural light.

Replace inefficient lampsReplace lamps with more efficient equivalents. For example, replace any 38mm diameter (T12) fluorescent tubes with slimmer 26mm diameter (T8) tubes or (T5) tubes, and specify all new tubes to have a ‘tri-phosphor’, or multi-phosphor, coating. This will save 10% of the energy consumption and improve the quality of lighting over the whole tube life. Note: slimline tubes will not work in some older fittings, so buy one new tube to check that it works before investing in bulk purchase. Alternatively, you could use LEDs, which use up to 80% less energy, and provide around 50,000 hours of use.

In some industrial settings (for example where bay lighting, freestanding and wall-mounted uplighters, floodlighting or street lighting is used), high pressure sodium discharge lamps (SON) should be considered. SONs combine high efficacy with long life and are particularly suitable where lamp access is difficult or expensive. SONs work well in situations where exterior areas need to be illuminated for long periods.

SONs are not made for frequent switching and, therefore, should not be operated by presence detectors for security lighting. They do not offer good colour rendering so may not be appropriate where accurate colour perception is required.

If good colour rendering or fast warm-up is important, then consider using metal halide lamps. Although these have a shorter life than SONs, they provide excellent, crisp white light and consume low amounts of energy.

For further advice please download our Lighting overview guide (CTV049).

20Chemicals sector

Energy management

For a business to be energy efficient, it is essential to have an energy management policy that demonstrates a strategic approach, with commitment from every part of the organisation.

Good housekeepingIt is important that both management and employees are aware of the benefits that energy efficiency can bring to a site. Ensure that the whole workforce is involved and committed to an energy efficiency programme. The Carbon Trust’s guide to Creating an awareness campaign (CTG056) could be helpful. See below for ordering information.

Remind everyone that effective energy management means:

• Cost savings.

• Healthier and more productive working conditions.

• An enhanced corporate image that can be promoted to customers.

Take responsibility and show commitmentCommitment to energy efficiency needs to come from senior management. An energy policy should be developed which clearly identifies the formal roles and responsibilities of the management team. One person should be made responsible for implementing energy saving initiatives. Ensure that adequate resources, in terms of time and money, are allowed for the role.

Conduct a walk roundReview energy use and procedures regularly by carrying out a walk round. Use a checklist to identity new sources of waste energy or new ways of saving energy. It is often useful to do this at different times of the day.

Monitor energy consumptionUnderstand energy consumption by reviewing the invoices received over the last year and build a picture of monthly energy performance. Larger sites will often have meters recording half-hourly electricity consumption and corresponding data should be available from the electricity supplier for comparison with your bills.

If a site does not have a half-hourly electricity meter then monthly meter readings should be checked and recorded in-house. It is also advisable to check and record monthly gas consumption in the same way.

For further advice please download the following publications:

Energy management guide (CTG054).

Energy surveys (CTG055).

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Fact:Most businesses in the UK could reduce their energy consumption by between 10% and 40%. However, it is important to be realistic – many companies start by aiming for annual savings of 5%.

Understand energy useMonitoring energy use helps to identify periods of high-energy use, such as periods of extra production. It can also demonstrate whether energy saving measures are having an impact.

As well as being a basic check on how the business is performing, energy use data can be useful when compared with production levels.

The simplest way to do this is to plot a graph comparing energy use against production levels like the one shown below.

This graph demonstrates that energy is being used, even when there is no production, and costs are still incurred. To reduce these costs, machinery should be switched off when not required, and lighting and heating only used as and when necessary.

The slope of the graph shows production-related energy use. Try to reduce the slope of this graph by using equipment more effectively. As energy saving measures in this overview are implemented, there should be a reduction in both the gradient and the intercept on the energy usage axis.

Figure 2 Comparing energy use against production levels

Comparing energy use and performance data month on month, year on year can also show where energy savings measures have had an impact.

For more information about energy management, contact the Carbon Trust. Relevant publications include How to monitor your energy use (GIL157) and Understanding your energy consumption (CTL001).

Set targetsRealistic targets should be set for energy savings – these will help to keep the momentum going and will help maintain employee awareness and interest. Set deadlines for the completion of each initiative detailed on the action plan and check to ensure that each has been completed.

Have an action plan and implement it An action plan should be developed that lists the improvements that need to be made, when they will be made and who will be responsible for making them. Improvements should be prioritised according to the potential energy savings and the time taken to recoup the cost (payback period).

22Chemicals sector

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Government energy-related regulation

Many chemicals companies have Climate Change Agreements (CCAs) with the UK Government. In return for meeting energy efficiency targets, companies receive an 65% rebate on the Climate Change Levy that they pay on their fuel. Companies need to carry out a series of energy efficiency actions and meet biannual milestones in order to comply.

Further information can be found on the DECC website www.decc.gov.uk/en/content/cms/emissions/ccas/ccas.aspx

Chemicals companies may find themselves liable to the EU Emissions Trading Scheme. In this scheme, companies are given emissions caps and can trade any carbon emissions saved if they stay within the required emissions limit. However, if a company exceeds its cap, then carbon allowances have to be purchased. Hence, this scheme is a powerful incentive for companies to save energy.

Further information can be found on the Defra website www.defra.gov.uk/environment/climatechange/trading/eu

The EU Integrated Pollution Prevention Control (IPPC) directive is further regulation that might be relevant to smaller sites or businesses not otherwise in a CCA. For more information, see www.defra.gov.uk/environment/ppc/ippc.htm

The Chemical Industries Association Broking and Trading Agency (CIABATA) is a subsidiary company of the Chemical Industries Association. CIABATA manages and administers the chemical sector climate change agreement with DEFRA. More information is available at www.ciabata.org.uk

Related publications

The following publications are available from the Carbon Trust.

GuidesEnergy management guide (CTG054)

Energy surveys (CTG055)

Technology overviewLow temperature hot water boilers (CTV051)

Heating, ventilation and air conditioning (CTV046)

Refrigeration (CTG046)

23Chemicals sector

Action checklist

In summary, for companies within the chemicals sector, there are a significant number of actions that can be carried out at no or low-cost. The following table gives a sample of the key opportunities, however, there are many more described in this publication.

Continued on the next page

24Chemicals sector

Cost Action Progress

Process control

None Check controls for calibration and to see if they are unnecessarily switched to manual

Low Check whether product is being over-processed

Motors and drives

None Switch off motors when not in use

None Reduce unnecessary load

Low Reduce unnecessary load

Medium Investigate higher efficiency motors and variable speed drives

Furnace/boilers

Low Check air/fuel ratio

Medium Check boiler insulation

Medium Review blowdown operations

Medium Investigate use of an economiser

Medium Investigate use of variable speed fans rather than dampers

High Consider purchasing a new boiler or installing CHP or renewables plant

Steam distribution

Low Check for steam leaks

Low Check condition of pipe lagging

Low Check for redundant pipework

Low Carry out checks on steam traps

Compressed air

None Stop any unnecessary use

Low Find and repair air leaks

Low If possible, reduce delivery pressure

25Chemicals sector

Action checklist (continued)

Cost Action Progress

Process operations

Low Check if the load to the plant can be reduced

Low Check if process utilities use (gas, water etc) can be minimised

High Consider alternative equipment configurations

Low Check that all hot surfaces are lagged

None-med Ensure the refrigeration system is adequately insulated

High Investigate alternative equipment

Low Check whether you have any leaks within the refrigeration system or other wastage

None Can purity of industrial gas be relaxed?

Medium Check for any opportunities for waste-heat recovery and use

Industrial buildings

Low-med Investigate different heating methods

None Check that heat is not being wasted when not required, or through open doors/windows

Medium Insulate roofs and walls

None Switch off lights and use natural light

Low Replace inefficient lamps

None Turn off unnecessary ventilation

Low Consider interlocked controls

None Control air conditioning temperatures and times

Energy management

None Develop an energy policy

None Develop an action plan

None Monitor progress on action plan and set targets

26Chemicals sector

Further services from the Carbon TrustThe Carbon Trust advises businesses and public sector organisations on their opportunities in a sustainable, low carbon world. We offer a range of information, tools and services including:

Website – Visit us at www.carbontrust.com for our full range of advice and services.

www.carbontrust.com

Publications – We have a library of publications detailing energy saving techniques for a range of sectors and technologies.

www.carbontrust.co.uk/publications

Case Studies – Our case studies show that it’s often easier and less expensive than you might think to bring about real change.

www.carbontrust.co.uk/casestudies

Carbon Trust Advisory – Delivers strategic and operational advice on sustainable business value to large organisations.

www.carbontrust.co.uk/advisory

Carbon Trust Certification – Delivers certification and verification services to companies and runs the Carbon Trust Standard and Carbon Reduction Label.

www.carbontrust.co.uk/certification

Carbon Trust Implementation – Delivers services to business in support of implementation of energy efficient equipment and energy efficiency financing.

www.carbontrust.co.uk/implementation

The Carbon Trust receives funding from Government, including the Department of Energy and Climate Change, the Scottish Government, the Welsh Government and Invest Northern Ireland.

Whilst reasonable steps have been taken to ensure that the information contained within this publication is correct, the authors, the Carbon Trust, its agents, contractors and sub-contractors give no warranty and make no representation as to its accuracy and accept no liability for any errors or omissions. All trademarks, service marks and logos in this publication, and copyright in it, are the property of the Carbon Trust (or its licensors). Nothing in this publication shall be construed as granting any licence or right to use or reproduce any of the trademarks, services marks, logos, copyright or any proprietary information in any way without the Carbon Trust’s prior written permission. The Carbon Trust enforces infringements of its intellectual property rights to the full extent permitted by law.

The Carbon Trust is a company limited by guarantee and registered in England and Wales under company number 4190230 with its registered office at 4th Floor Dorset House, Stamford Street, London SE1 9PY.

Published in the UK: March 2012.

© The Carbon Trust 2012. All rights reserved. CTV057.

The Carbon Trust is a not-for-profit company with the mission to accelerate the move to a low carbon economy. We provide specialist support to business and the public sector to help cut carbon emissions, save energy and commercialise low carbon technologies. By stimulating low carbon action we contribute to key UK goals of lower carbon emissions, the development of low carbon businesses, increased energy security and associated jobs.

We help to cut carbon emissions now by:

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CTV057