News

Case Studies

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Lay up procedure - Byworth Boilers

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Emerson patented combustion solution

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The safe operation of boilers - who's responsible?

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BOAS Assessors - The Key to our Success

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Bringing a Steam Boiler On-Line from Cold

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Biomass Boiler Explosion in Birmingham

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Medium Combustion Plant Directive News

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Testimonial - Ford Motor Company

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Use of Filming Amines and Reverse Osmosis in boiler water treatment

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Reducing boiler pressure saves energy – myth or fact?

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Environmental sustainability has never been so important and this pressure is leading many plant engineers to explore ways they can reduce boiler house energy consumption. A common idea is to reduce boiler pressure to save energy, but does it work? Chris Coleman, Marketing Product Manager at Spirax Sarco, explains how steam system pressure and fuel economy are interlinked. 

The pressure for companies to reduce their environmental impact is growing daily. Consumers, investors, governmental bodies, the media and many other groups are all increasingly focused on the need to lower emissions. This is leading many boiler operators to review their boiler house energy consumption with a view to reducing total carbon emissions and saving energy costs. 

One question we’re often asked is whether it’s a good idea to run a steam boiler at lower than its design pressure to save energy.

The answer is not always a simple yes or no; there may be bigger issues to consider other than relatively minor adjustments to boiler pressure. In particular, it’s vital to ensure that all condensate and flash steam is recovered and its heat re-used efficiently.

Ultimately, what really counts is ensuring that the steam distribution system is as energy efficient as possible.

Higher distribution pressure is more efficient

Generating steam at a higher pressure will require more fuel. However, at its simplest level, the same amount of energy is used whether the boiler raises steam at 4 bar g or 10 bar g. This is because it’s the connected load and not the boiler output that determines the overall energy consumption of a building or industrial plant.

We have to also consider losses around the system. Within the boiler itself these losses depend on the boiler’s combustion efficiency, the heat transfer efficiency of its combustion chamber and fire tubes, and flue losses, which are likely to be higher at higher boiler pressures. However, these rises are marginal when compared to the benefits of distributing steam at a higher pressure.

The most efficient way to run steam plant is to operate the boiler at higher pressures, with pressure reducing equipment to lower the system pressure at the point of use. Using higher pressures increases the boiler’s thermal storage capacity, helping it to cope more efficiently with fluctuating loads and minimising the risk of wet and dirty steam being carried over into the distribution system. It also cuts the cost of materials, insulation and labour, since smaller bore steam mains can be used.

Consider all losses

There will also be losses from the steam distribution system, including heat loss from pipework and fittings to the surrounding atmosphere, as well as steam leaks. Again, all of these losses will be greater at higher distribution pressures.

Potentially though, the most significant losses occur after the steam-using process, whether space heating for a building, or process heating in an industrial plant. Once the steam gives up the amount of heat that the process demands, condensate is released. In most cases, flash steam is also produced.

Now it gets interesting. If the condensate system is effective in recovering all or most of the heat in the condensate, and the flash steam is used by another process or fed to a recovery system, then losses will be minimal. In this case, the boiler operating pressure will not have much impact on the overall losses, and any efficiency gains may be offset by other considerations, such as the risk of wet and dirty steam being carried into the process.

On the other hand, if the hot condensate is not recovered effectively, or the flash steam escapes, then the losses will be large. In this case a lower operating pressure will produce lower losses. However, this would be an inefficient steam system and, rather than adjusting the boiler pressure, much greater savings could be made by improving the plant’s energy performance.

Achieving optimum steam distribution pressure

The optimum pressure within a system varies from plant to plant and depends on the maximum safe working pressure of the boiler as well as the minimum pressure required by steam-using equipment around the site.

Deciding on the optimum initial distribution pressure can be complex, taking in to consideration the application, equipment and safety issues. Allowances must also be made for steam pressure loss as the steam passes through the pipework to ensure the minimum pressure is met at the point of use. So it’s important that the pressure is not altered in a misguided attempt to reduce fuel consumption.

There are other considerations too, such as whether the existing control valves and heat exchangers are adequately sized if the pressure is dropped.

It can take a degree of expertise and experience to successfully balance conflicting factors and arrive at the optimum pressure for a steam system. That’s why many boiler operators would be better off getting advice from a steam system specialist.

Other ways to reduce fuel consumption

There are many effective ways to save fuel. It is estimated that industries could save up to 30% of the fuel feeding its boilers by combining established good practice with improved technologies.

Recover all condensate

Condensate can contain up to 20% of the energy in the steam from which it came. Returning water to the boiler feedtank typically recovers about half this energy, while the rest can be recovered by installing a flash steam vessel or pressurised condensate return system.

The benefits of condensate recovery do not end with energy savings, though. It also saves water and treatment chemical costs, and even effluent charges may be reduced because less water is discharged to drain.

Install automatic boiler blowdown

All boilers need to be periodically purged by blowdown, the key to which is removing only enough water to maintain contamination at an acceptable level. Dumping any more than this is a waste of energy and treated water.

Many boiler houses use blowdown valves that are manually opened at regular intervals and dump water down the drain. An automatic TDS (Total Dissolved Solids) blowdown controller is a better option. By continuously monitoring TDS build-up in the boiler, the controller opens the blowdown valve only as required. It is often cost effective to recover the heat from the necessary boiler blowdown using a simple flash vessel and heat exchanger system.

Creating the right boiler feedtank conditions will also reduce the amount of fuel needed to produce steam from hot feedwater. Using returned condensate, for example, to raise the feedwater temperature by 6°C gives a fuel saving of 1%. Ideally, feedwater should be maintained at 90°C.

Taking the next step

These are just a few of the factors that can determine whether a steam system operator is paying over the odds by running their plant below its optimum efficiency. A full energy audit can identify where energy is being wasted and suggest ways to win significant savings, however we know that some companies don’t have the necessary steam system expertise in-house. Therefore calling in an external provider like Spirax Sarco is often the best option. You can get in touch on ukenquiries@spiraxsarco.com

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Case Studies

Watkins Hire have provided CEA with some interesting case studies, click on the links to view What they did, How they did it, the result and the equipment used.

1. End User: A Major Utility Company

The Challenge

Due to a unforseen breakdown, a major utility company working on strict timescales had the urgent requirement for a 15,000kg/hr steam boiler to operate at 8 barg working pressure.

Read More Here...

 

2. End User: Luxury Apartments in London

The Challenge

A call was taken via Watkins Hire’s 24/7 Emergency Hotline regarding the urgent need for assistance due to the failure of an existing boiler at a prestigious residential block of 134 apartments in London

Read More Here...

 

3. End User: Luxury Apartment Building Management Company

The Challenge

A management company required a temporary boiler installation to assist during the planned replacement of existing site boilers for a block of 330 luxury apartments and swimming pool in the centre of London

Read More Here...

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Lay up procedure - Byworth Boilers

CHRISTMAS LAYUP PROCEDURE FOR YOUR BOILERS

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With many businesses closing for Christmas, Byworth’s Chief Technician, David Tilleard, discusses how to prepare a boiler for short term storage. David reports: “A boiler left idle for an extended period of time is likely to suffer corrosion as the normally low levels of oxygen scavenger are depleted. Any boiler that’s going to be left for a few days should be ‘laid up’.”

Read more of this story here. 

Visit www.byworth.co.uk for further case studies and news stories. 

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Emerson patented combustion solution

Take a look at this video which was the subject of the CEA's David Gunn Memorial Lecture, 19th October 2017, delivered in the House of Lords by Chip Rennie - Director, Global Industrial Energy Solutions. Whilst explaining "The "Art" of Combustion - Then and Now" Chip talked about the previous technologies of controlling fuel and air ratios and then discussed the modern way of controlling this air fuel mix and a new algorithm for controlling it, all of which is in the attached video just released by Emerson Process Management.

 

The CEA's Honorary President Dr Pete Waterman said "the presentation was extremely informative and has answered some very important questions for [him] and [his] guest Matt Conway, on recent developments in combustion technology". It was also very informative for many of the guests attending. For those that may not know, Pete Waterman has and still is very heavily involved in many aspects of Engineering from Heritage Railways rebuilding and renovation of steam locos through to the design, build and infrastructure for HS2 and all aspects of Engineering in-between, and it goes without saying, his passion for music.

 

https://www.emerson.com/en-us/asset-detail/patented-combustion-solution-from-emerson-improves-performance-1650444

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The safe operation of boilers - who's responsible?

If you are reading this, then the likelihood is you're an engineer with responsibility of the boiler plant in your organisation. Now that could be a factory, a hospital, a chemical plant, a prison or in fact anywhere with a boiler.

So, is the boiler plant your responsibility? Yes; you say, it is my responsibility.

The fact is, the over-riding responsibility for the safe operation of the boilers within your organisation sits with the head of your organisation. It may be the MD or the CEO or some other such title but for this exercise we will call him/her the MD. The chances are, they're not from an engineering background and possibly don't even know where the boilerhouse is, but they cannot get away from it, in law, they are responsible.

So what are their responsibilities?

Read Derry's Article Here 

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BOAS Assessors - The Key to our Success

Could you be part of the team?

The Boiler Operation Accreditation Scheme has been running for over 12 years now and is in a significantly enhanced and ‘steady state’ of operation after seeing over 3330 successful candidates pass through the scheme up to September 2017.

But what makes a successful training and assessment scheme?  One answer in the case of BOAS is the Assessors.

There is no such thing as a typical BOAS Assessor.  Sure, they all have a wealth of experience in the operation of steam and hot water boilers, and they have all been associated with the boiler industry in some way for most of their working lives, but they are all different characters and all highly professional individuals.  Some have an engineering consultancy background, some come from the H&S world, and some have spent many years operating plant at sea and on shore, but they all know their boilers.

Many of the dozen or so Assessors are retired, a few still have a full time role, and some are also BOAS Trainers; there is nothing wrong with being a BOAS Trainer and an Assessor as long as you do not assess the candidates you have trained.  Working in the BOAS scheme is a form of CPD for all those involved – we all learn something new every day from the candidates and the other professionals in the CEA involved in the scheme.

BOAS Assessors love to talk about steam and love to share experiences with their colleagues.  They take on the challenge of keeping up-to-date with their industry whilst encouraging the candidates they assess to know more about the plants they operate and increase their own knowledge.  A BOAS Assessment is a structured and quite rigorous process, but Assessors come away from their candidate interviews with the satisfaction of seeing good boilermen becoming safer and better boiler operators, and their managers and supervisors knowing more about their roles and the laws and best practices that underpin the industry.

Boiler explosions and related dangerous occurrences are rare in this country, and this is no accident.  Trained boiler operators and managers are now required to have BOAS by some employers, and insurance inspectors are looking for trained operatives when they inspect plant – it is a legal requirement to be trained for work activities, after all. 

The CEA awarded Kiwa the task of managing the BOAS assessment process and organising the Assessors.  They are always on the lookout for new Assessors to join the team.  A steady increase in the numbers being trained, plus the addition of a new category of operator and the continual five yearly renewals mean that the BOAS scheme is going from strength to strength.  Do you think you could join in with our success?

Please apply to Andrew Mathews at Andrew.mathews@kiwa.co.uk or Dave Kilpatrick at info@cea.org.uk.  We look forward to welcoming you to the team.

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Bringing a Steam Boiler On-Line from Cold

To help understand what needs to be done and why things need to be done in a certain way, the following procedure presumes that the boiler is completely cold and dry, such as after a prolonged shutdown or annual inspection.

Steps can be omitted for boilers with some residual heat still in them and a typical example of this could be the start up after a weekend shutdown where the boiler has dropped in pressure and cooled, yet still has heat in it.

Note: The need to heat the boiler slowly will be explained throughout this procedure and it can take many hours for a large cold boiler to be heated correctly to operating temperature and pressure. Timing will also depend on how much treated water is available to fill the boiler, so be prepared for a long day and you may have to include a shift handover procedure to safely complete the task.

To read to full article please click here. 

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Biomass Boiler Explosion in Birmingham

A factory worker has died and two others left in a stable condition following an explosion at a recycling plant in Oldbury, Birmingham. 

The man, in his 50s, suffered very serious burns in the explosion, in the early hours of Monday 7th August. Sadly he later died from his injuries.

Two other workers in their 30s and 40s also sustained burns in the incident. They remain in a stable condition in hospital.

The police were called by the fire service at 1:50am Monday morning. 

Health and Safety Executive chiefs said they are aware of the incident and will investigate.

Read the full article here. 

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Medium Combustion Plant Directive News

Now that the recent election is over Defra are able to re-engage with Stakeholders on current projects, the most pressing being MCPD.

A number of matters have arisen over the last few weeks:

Consultation

The Government’s consultation on the implementation of the MCPD ran between 16 November 2016 and 8 February 2017, and the results were published at the end of June.

Of the 112 responses received, the largest number of responses were from the Energy sector, followed by Industry, Local Authorities and Regulators.

Implementation Summary

MCP Timetable

AQMAs

One clearly overriding factor in these discussions is the scope and importance of Air Quality Management Areas.  The Directive (Art 6:9) allows the Regulator to impose stricter controls on emissions for AQMA and it is likely with current public pressure and interest that this will be done.

EA Guidance

NOTE – this is a short form of the document discussed at the stakeholder working group and further detail (especially for diesel generator rules) is available on request to the CEA.

See the full News article Here

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Testimonial - Ford Motor Company

I am very pleased to provide this testimonial on behalf of Ford Motor Company.

My role is Engineering Manager responsible for the Boiler House & estate maintenance for the Ford plant at Dagenham, Essex.

I contacted the CEA for advice on training after the completion of our new boiler house in 2015 on the recommendation of the boiler manufacturer.

I was contacted by David Kilpatrick who recommended the BOAS accreditation for Managers, Supervisors, & Operators, which we completed.

I found the course very informative giving us an excellent understanding of BG01, with the benefit of having it delivered on our own premises.

My team have all given positive feedback on what they received.

I have since attended the Technical Boiler House Risk Assessment conference which has been very useful in giving me the tools to enable implementing my own technical Risk Assessments.

The CEA are always on hand for advice and networking in other areas, on the recommendation of David Kilpatrick I have since started my team on an industrial gas qualification I-GAS, which is going well so far.

As a customer I have found the whole experience excellent and would most definitely recommend the CEA. Well done.

 

Dean Sheldrake,

Superintendent
Utility & Estate Services
Ford Motor Company Limited

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Use of Filming Amines and Reverse Osmosis in boiler water treatment

The Camberley plant is a large commercial laundry part of the CLEAN group of laundries. This plant processes up to one million pieces of linen per week on a two shift/7 day per week operation.

For Clean Camberly, the use of and RO plant and injection of amine is very successful.  The boilers have stayed in good condition with minimal scaling in the boiler. TDS stays low and constant so blowdowns are minimised with a good saving in energy.  They have little or no problems with the other parts of the steam system either.

L. Armitstead

Engineering Manager, Clean Camberley

June 2017

Please Note - This article is a personal view by the author based on their results of their steam boiler and system.

Also note - David Kilpatrick director of the CEA would like to point readers to the CEA guidance document BG04 which talks in detail about all aspects of Steam and Boiler Water Treatment. Pages 22 and 23 offer words of caution on when and where Amine can be used, as it may suit this closed loop process but please check with a steam boiler water treatment expert that it is suitable for your process. Because steam boiler water treatment is a complex subject CEA do not endorse any technical aspect of this article and it is highly recommended that the reader carries out a thorough risk assessment in accordance with BG04 to ensure the correct boiler water treatment is applied to your individual application. 

Click Here to view Full Article

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