Waste-heat recovery using ORC technology in the Middle East – Filippo Vescovo, Turboden

Today, I want to tell you about energy, and I think energy is very important to cement because cement is one of the most energy-intensive processes in the world. And I would like to do it with a presentation. I have some nice slides. Okay. So let's start with electrical energy. In this video, you can see some of the equipment that are consuming energy. So we have lots of rotating parts, mills, pumps, air compressors. We're talking about 100 kilowatt hour per ton of cement, which means in a 10,000 ton per day plant, about 1,000 megawatt hour, which is considering the Saudi Arabia average consumption, a city of 75,000 inhabitants. So a very important number. And thermal energy.

And when we talk about thermal energy, we talk about the kiln that should reach about 1,450 degrees. And to reach this temperature, we use natural gas mostly if you are in Saudi Arabia, but in other parts of the world, you can use HFO, coal, alternative fuels. We had some very nice speech about that. And here we're talking about 900 kilowatt hour per ton. Of course, this is an average value. Let's go to the very basic scheme of cement production. So we have our rotary kiln. The raw material is sent by the preheater. In the rotary kiln, we have the calcination process, and then the clinker coming out of the clinker cooler. But now I want to show you the thermal part of it.

So we track the temperature in every part of the plant. You can see the degrees Celsius here. So we have the highest temperature inside the rotary kiln. Then in the clinker cooler, where the clinker is coming out, we have about 400 degrees. And on the preheater, starting from 900 degrees, we heat up the material before going to the rotary kiln until here, where we are at 350 degrees, 300 depending on the specific plant, on the specific process. But what is important here is that we have a big amount of thermal energy that is not utilized in the clinker cooler and after the preheater.

Again, every cement factory, every geography is different, so you might have some need for the raw mill, coal mill. But still, you have an important amount of thermal energy that is not used. So we can recover this heat. And to do that, we will have two waste heat recovery boilers. One is at the clinker cooler, and one after the preheater. So let's have a look at the waste heat recovery boiler at the clinker cooler, where we have a dust content 10 to 30 gram normal metric cube. Type of dust is abrasive and temperature 250 to 350. And here we cool it down to 120 degrees. You can see also a video from one of our installations in Slovakia.

And then we have the preheater heat exchanger, where we have more sticky fumes, and here it is cooled down to 150, 200. Of course, these are average. Again, every process is different. Okay, coming back to our scheme. We recover the heat with a heat recovery heat exchanger, where we transfer the heat from the exhaust gas to thermal oil. We collect the thermal oil from the two heat exchanger. And now we can use this heat to produce electrical energy. We said that cement has a big need of electricity. So what we're doing here is collecting the excess heat, recovering it, and send it to our ORC to transform that into electricity. So what is the ORC?

ORC is a system in which its heart is a turbogenerator that is working with an organic fluid, and this is why it's called organic ranking cycle, to differentiate it from the steam turbine, the classical steam turbine. Here we're using an organic fluid that is evaporating at a low temperature and is working as a closed loop, meaning that we are just taking the thermal energy, transforming it into electricity. We are not consuming any fluid, and most importantly, we are not consuming any water, which is a very important thing in these geographies. And the ORC is what our company is producing, Turboden, but I will tell you more in the next slides.

But let's have a look at how an ORC system looks like. This is our plant we are very proud of. It's in Riyadh, a cement company. And these are very special days for us because we are starting this plant these days. We just got the news that it was starting being fed with the thermal oil, and yesterday, the first rotation of the turbines, and today or tomorrow, the first kilowatt electricity will be produced. So let's have a look at some features of this plant. Here you can see the thermal oil circuit. These tubes are coming from the waste heat recovery boilers. So here we're talking about two lines. So in total, it will be four heat recovery boilers. Thermal oil circuit is feeding the system.

We use thermal oil and not steam, and there are some advantage for that. You don't have a change of phase. It's liquid at all the temperatures. It is operating at low pressure and very easy to manage. Then we have the air-cooled condenser system, which is dissipating the excess heat after the expansion in the turbine. And this is fully designed and manufactured by our company in Turkey. And the important feature here is that it allows no consumption of water. And inside this building, we have the turbogenerator train and all the electrical cubicles. Here's some highlights of the project from theory to practice.

This photo was taken at the site visit before the starting of the project about two years ago. The signature, the design of the plant, and then the construction. And I want to present to you our company, Turboden. Turboden was founded in the 1980 by Professor Mario Gaja, and became soon the leader in first place of the biomass market in EU. In 2010, we entered finally the cement sector with our first installation in Morocco, in Aït Baha. And then we took important steps. We entered the MHI Group, Mitsubishi Heavy Industry.

And in the middle of 2010s, we developed this new concept of turbine that I just showed you in the Ryad Cement, which is a machine based on cyclopentane with air-cooled condenser, which had a great success, not only in cement, but also in other sectors, such as waste to energy and geothermal applications. We are about 400 employees worldwide, divided in three business units, including a dedicated after-sales team that is following all of our projects all over the world. And we have five production and engineering sites in Italy, Germany, Turkey, and US.

In 46 years of story, we delivered more than 470 plants for 1.1 gigawatt of clean power installed, and last financial year stays at 152 million euro. I want to show you some other selected references. Ciments du Maroc was the first plant that was installed, and 16 years counting, it's still in operation with more than 100,000 hours of operation. Then Metcem is another plant we are proud of. It's a 10 megawatt plant installed in Turkey from 11,000 TPD line. And the interesting fact here is that this company decided to trust the ORC technology after an installation with the steam technology. Then Lafarge Birids, a plant that we started last year.

It's a 10 megawatt electricity, and it was the first ORC in the Arabic Peninsula. Ryad Cement, which we talk about that. And then another important project that we are in a construction phase in Turkey for one of the biggest holding of the country. We're talking about three units of four megawatt. You can see the ACC is smaller. In '17 total, we installed 21 plants for a total installed capacity of 116 megawatt. Very quickly, I want to tell you why choosing the ORC. And I want to start with water. Our system is a water-free solution. For a 15 megawatt steam plant, in the best scenario, this is the amount of water that you are consuming.

We are talking about an Olympic pool every single day of treated water, which includes not only getting the water to the plant, it means also treating the water and trust the possibility to do that for years and years every single day. In ORC, we don't have such a problem. It's a completely water-free system. To cool down the system, you need air, a commodity that is hopefully always available. And then I asked the artificial intelligence to create this image, which is something that I saw with my eyes some years ago when I visited one of our plant. I saw an operator of the plant with six monitors. And I asked, "Who is following the ORC?" And they show me, this is the operator.

And it was interesting to me to see that ORC was one of the six monitors. He was, at the same time, checking also the RDF plant, the alternative fuel line, which is showing you that this system is a very automatic system. You don't need an ORC expert. You don't need a high pressure machineries expert because the ORC is operating at low pressure, and it is a very automatic system. And then we have the flexibility at different loads. This is very important. Cement production is not constant all the time. Through the day, through the season, through the years, you may change a little bit the production parameters. This is something we experience in many plants of us.

But the good thing of the ORC is that the ORC system can work with different thermal loads, even below 40%, which is not likely probably in cement. But you can see the high efficiency level, even at partial load. And the ORC is adapting automatically to changing in the thermal loads. So again, automatically switching. And then the reliability. 98% or above is our average number in more than 400 installation. And I think this is the important point for the investor, right? You want to install a system, and you want the system to produce energy at a very good availability rates. And this is my last slide. How to reach this 98%? Of course, I'm not trying to selling you a miracle here.

There is a need also of a competent local operator. Even though the amount of task needed is low, they must be done. We require a visual check every day, so a walk around the plant, and also time to time check and communication with our experts in Italy. And then the availability of the spare parts is also very important, and we are managing this together with our customer. With most of our customer, we know which are also the spare parts they have available in order to give a better service and to guarantee high availability. And then the after-sale support, which is something our company is very proud of.

We have about 60 engineers that are following most of our plants all over the world and supporting our customers. We also developed an AI to optimize the plants that we have in operation. So it is collecting all the data, the pressure, the production, the temperature, modelizing it, and giving advice or telling our customer how to optimize the system in order to guarantee a very high production throughout the operation. These are the references. And that was it. If you want to further discuss the topic, we are available at the booth, me and my colleague Mirco. We'd love to talk further with you about this. Thank you