Reducing operating costs with a chlorine bypass: Hans Jorgen Nielsen, LV International

Thank you very much, and special thanks to David, Thomas, Sylvia, and your team for letting me have a chance to present to you in this last round of sessions. It's an unbelievable setup you have made. Once again, thank you very much. And ladies and gentlemen, friends, competitors and clients, we all work in the cement industry and we're all sometimes bullied by people who don't know much, especially politicians, saying that we are very dirty people polluting a lot. So I would like to open up your eyes that we are not that bad.

If you try to see the development of CO2 during the last 75 years, you can follow the blue curve starting from 2000, just after the Second World War, at five billion ton per year, and today increased to approximately 40 billion ton. The red line shows you how much the population has increased during the same time. And you can see there's a very clear comparison between the number of people in the world and the CO2, except two periods. One period is in the '60s where Europe went through the Industrial Revolution. Then there's another jump in year 2000, 2010. That was when China developed rapidly. The lower graph shows the GDP, which you can see GDP also follow the CO2 very much.

But please remember the figure, approximately 40 billion ton per year. Despite the continuous growth of CO2 in the world, one of the industries that had been doing a great effort to reduce the CO2 is the cement. And you can see since 2020 until today, the cement has reduced the CO2 approximately 10%. So today, out of the approximately 40 billion ton of CO2 released by human activities, the cement contributes about 4%. There was a slight dip during the COVID, but the real dip came from 2020 when people, all of you, really made effort to reduce the CO2.

But I want to make you not so depressed by being in this industry because if you take the last two years, the CO2 has still increased 1.5 billion annually. And if you now see that the total cement industry release about 1.5 billion per year, it means that if we decarbonized completely, we would only delay the growth of CO2 by one year. Also, I think you should try to consider that only by breathing, one person releases approximately one kilo of CO2 per person per day. And with a population of eight billion people, then the total release of CO2 from all of us together in the world is double of the CO2 released by the cement industry.

I hope these figures will make you a little bit encouraged that we are not as bad when we work in the cement industry. But now I'll come to the main topic, which is the company ELVI, and what is our achievements during the past 25 years. Two years ago, ELVI, by power saving, mainly in our key product, vertical mill modifications, had saved a few hundred megawatts, which correspond to an annual saving of 1 million ton CO2 per year. We have modified approximately 700 vertical mills. And now I will show you how you can join us to reduce another 1 million ton easily.

That is by introducing the new projects we have launched very successfully over the past years, and today we are operating one big system in TPI in Thailand. We have one system under construction in Myanmar, in Kamba Cement, Myanmar, and we have just received another order from TPI in Thailand after he saw the result for the first. To understand chloride bypass, there are two temperature levels you have to watch. One is 750 to 800 degree, which is the melting point of alkali chlorides, and another one is the boiling point. And as you all know, in the burning zone, the temperature is about 1,500 degree, so the chlorides evaporate in the burning zone.

They circulate back into the preheater and back into the kiln. So if you feed approximately 0.01% chlorides feed plus fuel, and especially today, fuel is contributing when you use alternative fuel, you might end up to 2%, 1.8% chloride in the hot mill, which is considered the limit before you get coating problems in the inlet of the kiln. Therefore, if you feed more than the figure of around 0.01% chlorides in the feed, it's common to introduce a bypass where you extract some of the gas in the kiln inlet, take through either a heat exchanger cyclone, and collect the dust in a bag filter.

If you install a cyclone, that was the normal way about 10, 15 years ago to reduce the dust amount in the baghouse because nobody knew how to use this baghouse dust in a productive way. Therefore, the cyclone was introduced, the material from the cyclone reintroduced into the kiln system. But the objective was 100% to reduce the dust in the baghouse. Today, the system we have developed over the last few years and where we are running successfully, we do not try to minimize the dust.

Oppositely, we try to increase the dust, and instead of use only air in the quenching chamber where you cool from 1,150 to whatever, 380, or if you have no heat exchanger, 180, then we use some kiln feed to introduce to cool down from 1,150 to 850. That means the dust amount extracted in the baghouse will reach about 4% of clinker. And of course, if you have 4% dust on clinker basis, it will say if you have a 5,000-ton plant, you'll have 200 ton dust per day, which is prohibitive if you have to dispose it. So we have now a system where we can activate the dust and use it as a substitute in cement. This is a complete ELVI bypass system with calculations.

We have the extraction of the-- We have the cooling of the pipe, which is about 3% of the clinker capacity. Then if we want to minimize the airflow in the fan, we have a heat exchanger, and we collect approximately 4% on clinker basis in the baghouse. Now, what to do with this 4%? The new technology we have introduced is we activate the bypass dust in a kind of hydrator. It's not a hydrator as you see in a lime plant. There are some modifications done to the system, so we are able to activate the calcium oxide that comes out from this point to become what I will show you. When you take a look at the analysis of this dust, you have about 50% calcium oxide.

And by hydrating, converting the calcium hydroxide with water, we end up with about 50% calcium hydroxide. And as you all know, even none of us are old enough to know the Roman technology 2,000 years ago, cement was made in Rome from porcelainic volcanic ash and hydrated lime. So it's actually not a new technology. It's a repeat of what our ancestors did 2,000 years ago. Now try to look at the other part, this part, silica alumina iron. That's basically the clay part of the raw mix, and if that has been heated up to 900 degree, 1,000 degree, you have calcined clay. So when we extract the bypass dust, we add the raw meal dust for cooling down.

We actually get a mix of approximately 50% calcium oxide and 40%, 50% calcined clay. So we have a very simple calcined clay reactor that costs nothing to operate. It sounds simple to hydrate, and it is not so simple as such. That's why we have developed the technique over two years with an Indian company. Because if you take the hydrating in a lime plant, then you have what is called soft-burn lime, which is lime where the calcium carbonate has been carbonated at, or calcined at approximately 880 to 950 degree. But in the kiln, some of the dust goes back from the kiln system, so we have something that has been heated up more, what is called hot-burn lime.

So therefore, to activate the lime in a good way, that's why we have developed this, let's say, special hydrator. Our references show that we convert about 95% of the calcium oxide to calcium hydroxide. And even we spray water, don't be confused that the product is wet. It's a very exothermic reaction, and the material comes out completely dry with less than 0.4% moisture. And the beauty is that the activated dust will have a very high plane, 6,000 up, and the product size of the calcium hydroxide will be made less than five micron, which makes it both a nano product and a super active product.

We have some example where you can see this activated bypass dust increase the early strength from, in this case, from 12 to 15, the three-day strength from 24 to 28, the seven-day strength from 30 to 32, and the 48-day strengths remain flat. We have just, two months ago, commissioned a 20-tonne hour system at TPI in Thailand, and today we are able to add 15% of this hydrated bypass dust into the hydraulic cements with increased one-day strength, increased three-day strength, increased seven-day strength, and increased 28-day strength. And the beauty of it is that because of the super fine calcium hydroxide, the workability of the cement is extremely good.

So you don't need to add plasticizer, what is one of the drawbacks when you add more than, let's say, 10% calcined clay into a cement mix. So even I don't want to talk too much about CO2, I still have to explain to you that by doing what I just explained to you, there is a CO2 reduction, which is not the primary driver of this project. The primary driver is the money saved for the producer, but it gives you a benefit in the CO2. So this is if you have a heat exchanger. We try to recover additional heat from the bypass by bringing back the heated air. It's an air-to-air. The bypass gas come in, maybe 360, goes out as 180.

The cooling air goes in, let's say, ambient temperature, goes out at 120, 180 degree. That one we bring back into the cooling air vents with a reduction of the heat consumption of the kiln, or if you have a WSR system, increased megawatts in the WSR. This was a small, fast appetizer for you. But if any of you have more appetite to know more about the system, we have a booth just outside the exit. Now, before I finish off the meeting, I have to tell you some additional, that LVI will, from 1st of July, transfer all the assets, the business, the staff of 40 people, and myself into a new company owned by IKN.

This company will still operate in Thailand in the same premises as LVI, and the main idea for me is like this. I secure the employment of the staff. I continue still in the business, so. But I release my administrational part in the job so I can concentrate more to help you to lower CO2 and make your business more profitable. Thank you very much.