Industrial burner controls
How using electronic controls can significantly reduce costs
Energy costs in many of the industries that employ process heating are considerable. Negotiating a good fuel and electricity price can help to keep energy costs under control. But is your set up working as hard as it should be? Our industrial burner control experts examine the money saving solutions available in the UK.
Control is key
Controls for industrial burners have changed significantly in recent years; mechanical cam fuel:air ratio control has been replaced by self-checking fuel:air ratio electronic control. Oxygen trim has been added with flue gas re-circulation working to reduce emissions. Performance has been improved by increasing turn down ratios through more flexible control strategies and fan speed control, as well as by improved matching of load and demand from embedded 3 term PID systems.
Software options such as boiler lead/lag control can improve burner utilisation and communications software can greatly enhance information flow.
Most of the improvements to industrial burner controls have been introduced in the last few years. These controls can be specified on new burners or retrofitted to existing plant. It is now possible to reduce energy costs to lower emissions and to obtain trending information for management decisions. Self-checking controls with automatic logging and dial-out can release boiler house manpower for other process applications.
If you haven’t reviewed your industrial burner controls in the past five years, make 2019 the year that you take action.
Mechanical cams and linkages – is your boiler really as efficient as you think?
Consider a typical industrial boiler with mechanical cam control and let us assume that the burner has recently been serviced. At high fire, the oxygen level in the flue gas would have been set at a safe level – slightly above optimum – to allow for changes in conditions that affect combustion.
When burning oil, viscosity, calorific value and filter condition will all cause variations in combustion and when firing on gas the supply pressure and calorific value of the gas will both cause variations in combustion. The burner engineer will make allowances for any backlash in the linkages associated with the cam and will set the cam to ensure that the oxygen cannot fall too low.
After all, if the oxygen level in the flue gas is too low the risk of explosion is increased. In addition the risk of emissions containing unburnt fuel will also be increased, potentially resulting in fuel being wasted.
When oxygen is low, the flame from the burner lengthens which can cause damage to the tubes in packaged fire-tube boilers. However, if the oxygen level is set too high, there will be an increase in excess air and heat will be lost up the stack. So, the engineer sets the cam’s high fire point at a safe position above optimum and wastes heat up the stack.
The burner engineer’s next aim is to achieve a maximum turn-down ratio for the burner. Turn-down is the ratio of high fire to low fire. A turndown of 7:1, for example, would mean that the low fire fuel flow would be 1/7th of the high fire fuel flow. With mechanical cam controls the ignition point determines, and is the same as, the low fire point. For essential safety reasons, each time the burner starts up the boiler is purged with ambient air which cools the boiler.
The turn-down on a gas only burner might be 7:1 but on dual fuel burners the turn down is often only 3:1, meaning that on – off cycles are more frequent. If a boiler cycles on and off every 10 minutes then the number of purge cycles per day is 6 x 24 = 144. If purge typically takes 3 minutes, then there could be 3 x 144 = 432 minutes of purge every day.
By maximising the turn-down ratio:
- Burner on/off cycles is minimised.
- Heat is not taken from the vessel and wasted up the stack.
- The boiler can more readily respond to increases in load.
- Expansion/contraction cycling, which increases boiler downtime, is minimised.
At low fire, fuel flow is at its minimum and efficiency is less important than at high fire, so the burner engineer concentrates on acceptable combustion consistent with achieving maximum turn-down ratio and a reliable start-up. As before, he sets the oxygen level high. The other points on the cams are set to give a smooth curve between low and high fire with emphasis on achieving the best practical efficiencies at mid fire and above.
Mechanical cams and linkages have been around for so long that their limitations have been forgotten and everyone, including the plant manager, believes that they have their burners set and operating at maximum efficiency. However, it would be more accurate to say that a burner has been set to give the best possible result within the scope of the controls available.
How reviewing your electronic burner controls can reduce your energy bill
When an electronic fuel:air ratio control is retro-fitted the existing PID control, modulation motor and the cams and linkages are removed and servo motors (actuators) are fitted to air dampers and fuel valves. Likewise, when electronic control is specified on a new burner the burner arrives with its new control and its servo motors factory fitted. When using electronic burner controls, plant personnel can expect several benefits.
Linkageless burners have no backlash. On a frequently modulating burner, energy savings of up to 1% are common!
On an electronic burner control, the low fire point can be set lower than the ignition point which means that the turn-down ratio can be increased. In addition, burner on/off cycles and their associated cold air purges also can be reduced, resulting in energy savings.
While savings from reduced on/off cycles will vary with boiler utilisation, savings of 5% have been reported on a burner that prior to conversion had an on/off frequency of approximately once every 10 minutes.
A second PID control
Some electronic fuel:air ratio controls have two internal PID modulation circuits. If a plant does not run continuously, then this second PID control’s set point can be used to switch the boiler to a lower steam pressure or hot water temperature during periods of reduced activity.
One manufacturer employing this approach is Land Rover in Solihull. The company uses hot water for paint drying in their paint shop but the process is held on stand-by at night.
Using a second boiler set point provides energy savings of approximately 10% pa.
Fan speed control
With mechanical cam control and with basic electronic fuel:air ratio controls, burner engineers can sacrifice combustion efficiency at low fire to achieve an improvement in burner turn-down. Some air dampers leak and even when fully closed the air flow can be significant. In effect, engineers can reduce the fuel valve setting but cannot reduce the air to match. Combustion efficiency can be improved at low fire if the fan speed is reduced.
Fan speed control is an easy to add option on some electronic burner controls. By adding fan speed control, burner turn-down can be increased without compromising efficiency, and additional fuel savings can be achieved.
The benefits of variable speed control do not end here: When an inverter is used to slow the speed of an ac electric motor, electrical energy savings result. For example, when a fan motor is slowed to 25Hz i.e. to half speed, an 80% electrical energy saving is achieved.
Oxygen trim is a closed loop system available as an option on some electronic fuel:air ratio controls. Oxygen trim has been available for application to industrial boilers/burners for more than 35. Oxygen trim automatically and continuously compensates for the variables that affect efficient combustion. You will recall that on mechanical cam controls the engineer set the oxygen level high to retain a margin of safety. When oxygen trim is included the oxygen levels can be set at their optimum level. In addition, if the trim control is adaptive then it will contribute energy savings of approximately 2% to 3%.
Boiler sequencing (lead/lag) control and Communication Software
Modern electronic fuel:air ratio controls incorporate boiler sequencing and communications software.
Boiler sequencing control enables the plant operator to achieve better utilisation and additional energy savings are possible.
Communications software provides vastly improved information gathering and boiler operation data. Typical protocols are ModBus, ProfiBus and BACNET which allow plant operators to retrieve data for integration into master display systems and logging systems for analysis.
Flue gas temperature trend data can indicate when boiler servicing is due and oxygen trim trend data can indicate when burner servicing is due.
By reviewing your industrial burner controls strategy it is possible to achieve significant energy savings and substantially reduce outgoings. If you would like to discuss how our electronic burner controls could help your business please do get in touch.
Celebrating 30 years of worldwide success
Energy Technology & Control has been a global leader in the design and development of combustion controls and burner control technology for an impressive 30 years. To mark the occasion, ETC has created an infographic outlining some of the most notable dates in the company’s history.
It is fitting that the first date of interest should be the date of the management buyout in 1988. The next decade was a busy one as ETC started to build its reputation and gain traction in the electronic burner controls market, firstly securing European approval for the ETC3000 electronic air fuel ratio controller, before launching it in the UK market a year later.
In 1998 the ETC3000 electronic air fuel ratio controller received USA, UL and FM approval allowing ETC to enter the US market represented by Fireye Inc. In the same year the company were thrilled to receive the highest official UK award for British business – the Queen’s Award for Environmental Achievement – for the combined combustion of base and waste fuels offered by the ETC3900 burner control. The 90s ended on a high with approval received for ETC’s first fully integrated burner control system, the ETC1200, in 1999.
The millennium saw ETC set its sights on the world stage; in 2000 the ETC3000 burner control received Australian AGA approval, allowing ETC to market its products on the other side of the world. In 2006 the ETC6000 burner management system was launched – quickly receiving European approval – and leading to ETC’s first project with HP-Consulting in Germany in the following year.
In 2008 the ETC6000 series burner management system received UL, FM and AGA approval. This led to partnerships being established with; Italian company General Bruciatori in 2008, Spanish company E&M Combustion and Czech company PBS Power Equipment in 2009, the following year ETC agreed partnerships with Hamworthy Combustion in France and Gastech-Energi in Denmark, finishing 2010 in a strong position with its burner controls and burner management systems being fitted throughout Europe and beyond.
In 2011 ETC strengthened its position in Italy securing a second partnership with Italian OEM Bono Energia. The company also added two new models – the ETC6008 and ETC6009 – to the established ETC6000 series burner management system range of combustion controls. The ETC6008 & ETC6009 are designed to address applications where bio and waste fuels are being used. The year closed on a high with a partnership being confirmed with Steam House Africa in South Africa, opening the door to the sizable African market.
The ETC6003 burner management system integrated controller for dual gas burners was launched in 2012, the same year that ETC partnered with Brazilian company Steammaster, its first South American partnership. In 2013 ETC strengthened its position in France, establishing a partnership with Cometi Services, this saw it responsible for supplying most existing Hamworthy France sites.
The last five years have seen ETC strengthen its position in Australia, securing a second partnership with O’Brien Energy. The company has also launched exciting new products including, the ATEX Zone 2 actuators and the Class 1 Division 2 actuators.
Now with over 30 years of experience ETC is looking forward to solidifying its position in its current markets and extending its reach into new territories. Contact the team to find out more about the company’s range of burner control products.
ETC launches responsive new website
Energy Technology & Control, a global leader in the design and development of combustion controls and technology, is proud to launch a sophisticated new responsive website.
With more than 30 years’ experience designing and manufacturing innovative electronic burner controls for industrial applications that cut energy costs and emissions, Energy Technology & Control decided now was the time for its online presence to more closely match its technological prowess.
The company – which prides itself on supporting British industry by ensuring all of its products are made in Britain – always strives to be at the forefront of research and development; it’s unique and sought after ability to label combustion control products with its clients own branding has allowed them to gain a worldwide reputation for delivering trusted products.
The combustion control products produced by Energy Technology & Control form the cornerstone for its customers businesses, many of whom have confidently built their own reputation based upon this close and very productive working relationship.
The newly launched responsive website allows the company to strengthen its online presence and extend its reach into new markets and new countries.
Managing Director Martin Thirsk said: “As a company, we pride ourselves on our solid customer relationships – tailoring products to meet our customers’ applications – and strong emphasis on R&D as such all of our burner control products are approved to international standards.
“We are confident our new website will give us a solid foundation online with which to break into new markets and further extend our global reach, we are keen to forge links with new clients in new countries helping to support their industrial growth. We are also pleased to be able to consolidate our offering for our existing clients.”
Contact the team to find out more about the company’s range of burner control products.
Energy Technology & Control Ltd has expanded it’s range of servos to include EX actuators (servo motors), these are approved for hazardous area operation. They are variants of the ETC6023 and 6024 CANbus type, with 20Nm and 40Nm actuation force respectively.
They are marked as ETC6023-Ex and ETC6024-Ex and are compatible with all OEM variants of ETC6000 series controllers.
Ex type marking – ll 3 G Ex nR llC T5 Gc
Evaluated and certified by ExVeritas
Energy Technology & Control Ltd, a UK manufacturer of electronic Burner Management Systems, has expanded its range of combustion controllers to allow waste and bio-fuels to be fired either independently or simultaneously with a conventional gaseous or liquid base fuel.
Simultaneous firing of fuels can usually be achieved using conventional products but waste and bio-fuels are often characterised by variable availability and inconsistent calorific values. To overcome this an algorithm within the controller software enables safe and efficient combustion to be achieved; an external signal is used to indicate the proportion of waste fuel that should be used across the firing range. Oxygen trim ensures that any variability in either the fuel calorific value or external atmospheric conditions does not compromise combustion efficiency.
ETC6008 and ETC6009
The ETC6008 caters for liquid and gaseous fuels to be fired either independently or simultaneously. A second new model the ETC6009, is designed to allow a gaseous base fuel to be mixed with a gaseous bio or waste fuel and includes the provision for valve proving on two separate gas trains. The ETC6009 can be further enhanced to facilitate the firing of a back-up liquid fuel. The full range of ETC peripherals including a 10.4” touchscreen, CANbus servo motors, and temperature and pressure sensors are all fully compatible will all the new models.
russian language support
New ETC6075 Hi Resolution Touchscreen Launched
The ever popular ETC6075 Touchscreen HMI has been upgraded to an 800 x 600 pixel resolution display. Existing users will immediately notice the crispiness of the graphics and text as well as increased performance of the touch panel itself.
ETC has also taken the opportunity to give the product a facelift which includes a new boiler mimic graphic and a built-in help facility that allows the operator to call up relevant sections of the Operator’s Manual during normal operation and when commissioning the burner.
The memory card slot previously used for firmware updates has now been replaced with a USB port and all ETC6075 displays will now be supplied Ethernet ready allowing local communications using customers’ own Ethernet networks or remotely using the built-in web server.
SIL 3 Safety Integrity Level loop
ETC6000 Burner Controls Gain AGA Approval
Energy Technology & Control Managing Director, Martin Thirsk commented ‘The addition of AGA to the list of approvals for the ETC6000 Range that already includes UL, FM, CE & TRD underlines ETC’s commitment to supplying burner controls that are approved globally. In the current economic climate many of our customers are looking to export markets as part of their corporate strategies. AGA certification comes just weeks after the ETC6000 was successful in being approved to the EN61580 (2001) standard allowing the ETC6000 Burner Controls to be selected for systems requiring equipment suitable for inclusion in a SIL 3 (Safety Integrity Level) loop.’