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New fuel-saving options offer rapid payback and payoff

Reinier Bakker à‚ 
As ABB Turbocharging embarks on a major upgrade contract in Brazil, the company’s Reinier Bakker outlines the challenges and subsequent success stories of the upgrade process.

ABB Turbocharging is carrying out major upgrades to a series of power plants in Brazil.

The deal is part of the company’s collaboration with Wärtsilä and will result in the upgrading of 30 turbochargers in a series of plants operated by the Finnish firm.

“Every upgrade and every customer is different”, says ABB Turbocharging’s senior manager of OEM Service Sales, Reinier Bakker, and here he outlines what makes the Brazilian deal unique.

Q:

What role do upgrades play in a country such as Brazil, which is heavily investing to expand and rejuvenate its power systems?

A:

Upgrades play a big role. With these packages, you have an upgrade of the installation with an added benefit of fuel saving, and that’s what everyone is looking at these days, so the project essentially pays for itself. The return on investment is typically three years.

Q:

Outline the upgrades you are carrying out in Brazil?

A:

There is a conversion of something like 15 engines and these power plants supply to the grid. We are talking about upgrading 30 cartridges and one spare cartridge on multiple plants. So this upgrade is a great way to meet – or even increase – productivity above and beyond what you’d be able to do in the engine. And for engine providers who have to show their customers that their engines will be as productive as possible, this type of additional gain constitutes a real advantage, especially for companies with contracts stipulating productivity targets.

Q:

What is notable about the Brazil upgrades?

A:

The turbocharger stays on the engine – basically everything happens inside the turbocharger. The turbocharger and the housing stay the same. You just take out the cartridge, put your new cartridge in, and it is done within one day. The deal is between ABB Brazil and the engine builder in Brazil, and our team will implement it all on the engine. Our guys are also doing the regular maintenance, but the turbochargers and engines themselves are under an O&M agreement with the engine builder.

Q:

Had this sale been long in the planning?

A:

Well, the customer had only our simulation, and then all of a sudden, their Brazilian sales organization put in an order for 31 cartridges and wanted to know when we could supply. The orders are all in, and the first conversions began in the summer. Normally, customers are cautious about trying new solutions – a small change here or there, to see how it goes. In Brazil they want to combine this order with an upcoming SIKO exchange, which is an exchange of key rotating components at a set time for safety reasons.

Q:

What did you first learn in the process of developing the upgrades?

A:

That we had to collaborate closely with the engine builder to make the concept work. It was our work together with the engine maker – who was also interested in upgrades as an option – that enabled us to see that with the right modifications to both the turbocharger and the engine, we would in certain cases be able to achieve up to 3 per cent in fuel savings.

Q:

When did you put things in motion?

A:

We started with an upgrade in 2011 that required a complete change on the engine, and the engine OEM introduced Miller timing with a new cam-shaft. Putting in a new turbocharger made that possible. You almost could say that a matching process was implemented with the new turbocharger. And practice confirmed our theory about these new modifications – we achieved over 2 per cent fuel savings as a result of matching the turbocharger and the engine together in a completely new combination.

Q:

Outline the first meetings between ABB Turbocharging and the engine builder?

A:

There were two sessions in which we looked for the first time at the real technical, matching, engine and turbocharger data to find out what new operating values we would be able to achieve. The turbocharger and the engine need to fit together as well as possible in the given environment, so you minimise the amount of efficiency lost through pipe connections. So we worked a lot to optimise the positioning of the turbocharger and our work did confirm a new engine-turbocharger combination in those two sessions, so they were very productive.

Q:

What was the most crucial technical finding to come out of your talks?

A:

Probably that we needed to make sure that our solution would operate within the right boundary conditions. We didn’t know in detail what our partners on the engine side wanted to do in terms of tuning the engine and what introducing Miller timing could bring with respect to fuel savings.

Q:

How is speed margin affected by upgrades?

A:

A turbocharger is always designed to run at a particular rotation speed, but it can operate efficiently at higher speeds – at least up to a point. Speed margin is the range between a turbocharger’s standard operating speed and the maximum speed at which it can still run efficiently. When ambient temperature increases to, say, 45à‚°C from 23à‚°C, the rotor has to turn faster in order to pump the same amount of air into the turbocharger. Speed margin allows the turbocharger to increase its rotation speed and pump more air into the engine at varying temperatures. A power plant at sea level will have a different turbocharger specification than one at high altitude. In practical terms, then, if you increase the speed margin with an upgrade it means you have more flexibility in the turbocharger operation in different environments, including altitude and temperature.

Q:

How significant is the drop in temperature achieved through an upgrade?

A:

It’s a very significant drop. Normally, engines run at a very constant temperature, and only vary plus or minus 5à‚°C. With an upgrade, you can achieve a drop in temperature of up to 35à‚°C. A significant drop would be -20à‚°C, so fall of -35à‚°C is absolutely huge. If you’re able to get the same engine output with a reduced temperature, it will have a positive impact on thermal fatigue, and it will also have a positive effect on the fouling of the turbocharger.

Q:

Your first upgrades happened outside of Brazil. What sticks in your mind about the very first technical sessions for those upgrades?

A:

During those sessions with the engine maker, we did simulations about the potential improvements that could be reached with the upgrades we were proposing. Those were simulations on fuel savings, temperature reduction and on pressure. Since it was our first upgrade project, there was no chance to confirm the simulation with actual field measurements. Your first couple of run-throughs become your points of reference. By now we know with the upgrades that we’ve done just how accurate that first simulation was. So when we talk about doing an upgrade, we’re talking about providing a better turbocharging solution by simulating both the old and new situation with a high degree of accuracy.

Q:

When you say high degree, what sort of per cent are you talking about?

A:

We were within 10 per cent of the actual measurements of the simulated value. Actually, the measurements were slightly better than the simulation – and that is incredible. That is also true for the temperature or fuel-savings curves, they are measured as a function of the engine load. So you simulate it at 50, 60, 70, 80, 90, 100 per cent of the possible load, and then you do the measurement in the same way. And what we saw was a good correlation between the simulation and the measurements.

Q:

How do these figures compare with a regular overhaul?

A:

With a regular overhaul, you also get some savings, as a result of cleaning the engine and turbocharger. But here, in the measurements that we did, we cleaned everything before we began to measure our comparative data. The 2 per cent fuel savings is calculated through the comparison between the old turbocharger once it had been cleaned versus a clean, new one.

Q:

And what did doing the upgrade mean in terms of operational benefits?

A:

It was an improvement in every way: lower fuel consumption, higher speed margin and lower engine exhaust temperature. The upgrade enabled new, more flexible, wider boundary conditions that allowed us to make changes that were ultimately all good, and only good.

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