Global Cement speaks with Ismail Doğan, Cement Production Manager at Nuh Çimento, about this remarkable plant’s history, process and sustainability initiatives, plus how it fits into the busy Turkish and Mediterranean cement sector...
Global Cement (GC): Please could you introduce Nuh Çimento?
Ismail Doğan (ID): Nuh Çimento was founded in 1966 and it began production in 1969 with a capacity of 0.4Mt/yr. It has since expanded massively to include three parallel lines. Lines 1 and 2 each have a clinker capacity of 1.1Mt/yr with kilns from KHD and four stage preheaters from the Austrian company Ömag. They were commissioned in 1969 and 1971 respectively. The third line was built in 2005 by FLSmidth, with an FLSmidth kiln and Omag preheater. It has a clinker capacity of 2.3Mt/yr. The plant’s total 4.5Mt/yr clinker capacity makes it the largest plant in Turkey and Europe, translating to a cement capacity of around 5.7Mt/yr.
GC: Can you describe the production process?
ID: Our crushing section crushes clay and limestone taken from our captive quarry, plus gypsum, bauxite, iron slag, marl, or iron ore in three separate crushers. The main limestone / clay crushers are two 1500t/hr machines from the former Friedrich Krupp group.
After two 50,000t homogenisation domes, the material is analysed using two SABIA cross-belt analysers and is taken to the raw mill section, where three Loesche vertical roller mills with dynamic separators grind the <30mm feed to 12% residue on a 90µm sieve. Raw mills 1 and 2 have been extensively optimised over the past 12 months to increase efficiency and throughput. Similar work on raw mill 3 is ongoing. The mill specifications are shown in Table 1.
The ground material is further homogenised and sent to the three kiln lines. More details about the kilns are shown in Table 2. Each has a PASEC pre-calciner and pre-heater tower from Ömag. We recently installed oxygen-enrichment systems on kilns 1 and 2.
Following three coolers, clinker is stored in four silos with a total capacity of 0.25Mt (2 x 25,000t + 2 x 100,000t). The cooler on kiln line 1 was recently upgraded to a new FONS design.
After the silos, clinker is ground in four ball mills, each with roller presses. Mills 1 and 2 each have a production capacity of 140t/hr for Portland cement or 180t/hr for cement that contains 40% pozzolans at 4000 Blaine. They were supplied by Polysius, with KHD roller presses. Mill No. 3 is from FLSmidth, with a production capacity of 180t/hr for cement that contains 20% pozzolans. Cement mill No. 4 has a production capacity of 300t/hr for cement that contains 40% pozzolans at 4000 Blaine. In 2018 two KHD roller presses were added before mill 4, which increased its capacity to 408t/hr. This figure is enough to make Cement Mill No. 4 the largest ball mill for cement anywhere in the world. It is a big highlight!
There are nine cement silos, 2 x 5000t, 4 x 2500t, 1 x 10,000t and 2 x 28,000t. One of these was installed in 2018, which increased the plant’s cement silo capacity from 60,000t up to 86,000t.
Raw Mill No. | 1 | 2 | 3 | Total |
Supplier | Loesche | |||
Type | LM 38-4 | LM 46-4 | LM 63.4 | |
Commissioned | 1988 | 1994 | 2004 | |
Capacity (t/hr) | 200 | 300 | 480 | 980 |
Above - Table 1: The plant has three Loesche vertical roller mills.
Kiln line No. | 1 | 2 | 3 | Total |
Kiln supplier | KHD | FLSmidth | ||
Preheater/Calciner | PASEC design, Ömag | |||
Year commissioned | 1969 | 1971 | 2005 | |
Capacity (t/day) | 3200 | 3200 | 7000 | 13400 |
Capacity (Mt/yr) | 1.1 | 1.1 | 2.36 | 4.56 |
Length (m) | 59 | 66 | ||
Diameter (m) | 4.2 | 5.5 | ||
Speed (rpm) | 3.3 | 3.4 | 4.5 |
Above - Table 2: Summary details of the plant’s three kilns.
GC: You mentioned some of the types of cement produced when referring to the cement mills. What other types of cement does the plant make?
ID: Nuh Çimento produces various types of cements that comply with TS EN 197-1 and TS EN ISO 10426-1. The plant has CE marking licenses and also Certificate of Constancy of Performance for all cements produced. It makes five types of clinker: OPC clinker, sulphate-resistant clinker, low alkali clinker, low chromium clinker and API Specification Q1 oil well cement clinker. From these, the plant can produce: CEM I 42.5 R, CEM I 42.5 R (ASTM C150 TYPE I/II), CEM I 52.5 N, CEM I 52.5 N (NF-AFNOR), CEM I 42.5 R - SR5, CEM II /A-P 42.5 R, CEM II/ A-S 42.5 R, CEM V/A (S-P) 32.5 N, and, since 2009, API oil well cement.As part of our efforts to reduce CO2 emissions, and offer new products to the market, we have also started to market granulated blast furnace slag (GBFS) at 5000 Blaine. This is sold as an additive to local ready mix concrete producers. The plant processed 48,000t of GBFS in 2019.
GC: How are products dispatched from the plant?
ID: Cement is dispatched in bags via the packing plant, as well as in big bags, by bulk truck and by sea. The plant has its own port, which is connected to the plant via a 3m-wide tunnel that runs underground for 300m. It houses a conveyor that is connected to an automatic ship loading system at the port for the export of cement, clinker and similar products. This facility was installed in 1996 and was the first in its field within Turkey. We also use it to bring in some raw materials.Fuels and Environment
GC: Which types of fuels are used?
ID: All three lines are predominantly fired with steam coal, petcoke, natural gas and fuel oil. At present the plant is mostly reliant on coal, but we can use greater proportions of natural gas and fuel oil if needed. There are five coal mills. Coal mills 1 and 3 feed kiln line 1, coal mills 2 and 4 supply kiln line 2 and coal mill 5 feeds kiln line 3 (See Table 3).
To decrease the amount of coal used, the plant now uses magnesium-containing additives in the kilns. This has increased petcoke use without increasing the alkali content, enabling greater use of this calorific fuel and higher process stability. The additive is now produced by one of our group companies and is sold to other cement producers in Turkey and abroad.
The plant also has a 250t/day sewage sludge drying plant, which uses recycled flue gases to dry the sludge to generate an alternative fuel with a calorific value of 10.5 - 12.5GJ/t. Almost 3% of the plant’s thermal energy is supplied using this fuel. This reduces CO2 emissions drastically, not only by reducing fuel consumption, but by recovering waste heat and preventing methane gas from being released from the sludge.
The plant also uses refuse-derived fuels (RDF) from municipal sources following the installation of a 5t/hr feeding system from Di Matteo in September 2012.The plant can also burn hazardous wastes.
We are also carrying out a project to reduce the specific clinker thermal energy requirement and raise clinker quality by using CaF2 as a mineraliser. This lowers the temperature needed in the kiln. It is predicted that the thermal consumption will be reduced by 5 - 10%.
Coal Mill No. | 1 | 2 | 3 | 4 | 5 | Total |
Supplier | Loesche | |||||
Type | LM 16-2 | M 28-3 | ||||
Capacity (t/hr) | 12 | 50 | 98 | |||
Rollers | 2 | 3 | ||||
Feed size (mm) | <40 | |||||
Output (% on 90µm) | 12 | |||||
Ouptut moisture (%) | <1 |
Above - Table 3: The plant has five coal mills, all from Loesche.
Additive Mill | 1 |
Supplier | Polysius |
Capacity (t/hr) | 125 |
Table diameter (mm) | 4100 |
Feed size (mm) | <30 |
Feed moisture (%) | 4 - 7 |
Output (% on 90µm) | 6 |
Output moisture (%) | <1 |
Above - Table 4: Details of the Polysius additives mill.
GC: Can you expand upon the plant’s environmental performance away from the pyro-process?
ID: Ensuring environmental sustainability is a key element of our daily activities and decisions in Nuh Çimento. Although our main priority is to be in compliance with environmental regulations, energy efficiency and recovery, as well as alternative raw material and fuel use, water efficiency, waste reduction, lowering our carbon footprint and biodiversity management are all strategic issues for our company.
The three main stacks are connected online to the Provincial Ministry of Environment and Urbanisation, which can scrutinise them at any time. The plant operates with an average dust emission of 3 - 17mg/Nm3, which is far below the upper limit value of 50mg/Nm3. Our NOx emissions are kept within limits by the use of selective non-catalytic reduction (SNCR) systems on each of the three kilns. There are also online SO3 and loss-on-ignition analysers on the cement mills, the second such application anywhere in the world.
Currently, the equivalent of 850kg of CO2 is emitted into the atmosphere per tonne of clinker produced. In an effort to reduce this, the company has increased the production of products with low clinker factor and installed a waste heat recovery (WHR) facility from Sinoma in 2011. Over the three lines we have seven boilers and one turbine generator, to produce around 25% of our total electrical needs. One of the boilers was recently upgraded to produce more electricity. For the remainder of our power needs, we source increasing amounts of renewable power from hydroelectric sources.
The plant has also commissioned a 600m3/hr desalination plant, with the water used to cool the kilns, mills and crushers, as well as for dust suppression and on nearby fields. This system has increased the proportion of water that the plant recovers and reuses to 41%.
In the quarry, we have switched from diesel to electric power for raw material extraction, drilling and loading vehicles. These are charged using electricity generated from the WHR system, as well as from fuel oil generators. This has resulted in a 48% drop in CO2 emissions from activities in the quarry and saved on fuel oil costs.
In the quality control department we have conducted a project that, based on input parameters, predicts the 1, 2, 7 and 28 day strength of mortar cubes using mathematical modelling. This makes it possible to intervene early in the production process if the prediction is off-spec. The software, named ‘Resilient’ makes it possible to estimate strength results with 5% accuracy to 28 days.
Finally, in the kilns, we are now using energy-saving multi-layer refractory bricks. This results in a 60 - 80°C reduction in kiln shell temperature.
GC: How do low clinker cements fit into the sustainability picture at Nuh Çimento?
ID: The production of lower clinker cements is rising. For example, selling more CEM V/A (S-P), CEM II A-S 42.5 R (instead of CEM IV/B 32.5 R, CEM I 42.5 R respectively) and the introduction of CEM II B-S 42.5 R has lowered CO2 emissions.
GC: What can you tell us about the plant’s process control systems?
ID: The implementation of expert control systems (with autopilot-like functions) has been completed on line 1 and is underway on lines 2 and 3. A similar system is installed on cement mill 1 and others will follow in due course. These provide higher levels of energy efficiency, quality control and process stability by making rapid and appropriate automatic adjustments, faster than a human operator can.
GC: When was the last maintenance period and what work was undertaken?
ID: Line 3 was stopped for a 20 day maintenance period in the summer of 2020. Some refractory linings were changed, cooler plates were repaired and there were some minor projects on the raw mill and coal mill. The filter bags in the raw mill bag filter were completely changed for new ones.
GC: How did the coronavirus outbreak affect day-to-day operations at the plant?
ID: From the start of the outbreak 50% of staff have worked from home. Production has not been affected. The plant unfortunately saw one case of Covid-19, but this person has since fully recovered.Markets and the Future
GC: Can you comment on recent cement production and distribution trends at Nuh Çimento?
ID: Cement production was 2.94Mt in 2019 and we are due to produce around 3.6Mt in 2020, a 22% increase year-on-year. The plant’s main geographic market is the Marmara Region, concentrated around the Anatolian Side of Istanbul, as well as in Kocaeli, Sakarya, Bursa and Yalova. The transportation of bulk and bagged cement is carried out by trucks and silo trucks.
GC: We are aware that the plant is one of Turkey’s major cement exporters. What is the current split between domestic and export sales?
ID: Export sales of clinker and cement are very important to Nuh Çimento. In the eight months to 31 August 2020 the plant exported 1.03Mt of clinker and 1.15Mt of cement, whereas the local market received only 0.95Mt, about 45% of total cement sales and 30% of our total volumes.
The plant exports to more than 50 countries including to North & South America, Africa, Europe, Asia, the Indian Ocean, the Caribbean and Russia. In 2019, Nuh Çimento sold more low alkali cement to the US than any other exporter. Our low (<2ppm) chromium cement is popular in Europe and Africa.
GC: How much cement is sold in bags and how much is sold in bulk in the domestic market?
ID: In the eight months to 31 August 2020, the plant sold 95% of its cement in bulk, with 5% in bags.
GC: When we last spoke to Nuh Çimento in March 2013, the plant manager placed high importance on large infrastructure projects. Is Istanbul still in ‘fast build mode,’ or have infrastructure projects slowed down?
ID: At that time there would have been many large projects, including the Yavuz Sultan Bridge, the Osmangazi Bridge, the Büyük Melen Dam, the Sakarya Akçay Dam, the Şile Ağva Highway and several Metro Projects. Many of these have come to fruition in recent years. Since August 2018, however, the depreciation of the Lira, the local elections held in March 2019 and now the coronavirus pandemic have led to a significant slowdown and postponements of infrastructure investments. That said, Nuh Çimento managed to get a significant share from the ongoing large infrastructure projects, including the Northern Marmara Highway, construction of the second runway at the Sabiha Gökçen Airport and various Metro and High Speed Train projects.
GC: How does the EU Emissions Trading Scheme price rise affect your plant? Are you worried that a Carbon Border Adjustment (CBA) could restrict sales to the EU?
ID: If there are such changes in the EU ETS in the future, our competitive power within the EU market will clearly decrease. However, I believe the scale of our plant will insulate us from this effect better than some of our Turkish competitors. All Turkish exports to the EU would be less competitive, but ours would be affected to only a limited extent.
GC: What is the biggest threat to the continued success of Nuh Çimento over the next 1 - 5 years?
ID: The main issue going forward will be how the Turkish construction sector recovers after the coronavirus pandemic passes, but our success is not just related to consumption at home. As a major exporter, we are also dependent on sustained demand from many markets in the Mediterranean and further afield. Any of these could be badly affected by economic, political or coronavirus-related changes in the future, with little or no warning.
GC: What is the biggest opportunity for the plant over the coming 1-5 years?
ID: Nuh Çimento, which has a strong financial position in its region, proximity to the market, high competitive power and high quality products and services, is in a position to maximise its profitability in the domestic market and in foreign markets with a competitive exchange rate. In addition, by turning the economic crisis into an opportunity, it can make various investments and / or profitable purchases in domestic and foreign markets. The fact that Urban Transformation, Channel Istanbul, Metro Works and other infrastructure investments will be realised in the Marmara Region, the market in which we are most effective, is seen as a fantastic opportunity for the future.
GC: Ismail Doğan, Thank you for your time today
.ID: You are very welcome indeed.