Croatia has a relatively small cement industry with five cement plants, three of which are owned by Cemex Croatia, Croatia's only oil well cement producer. The Sv Juraj cement plant in Kaštel Sućurac, Kaštela is Cemex's most energy-efficient worldwide for specific heat consumption. It is also American Petroleum Institute (API) certified for oil well cement production. Here Global Cement reports on its recent visit to the plant, where Cemex Croatia's cement operations director Marijan Vuko described the company's operations.
Cemex Croatia overview
The oldest Croatian cement plant dates back to 1904, when Sv Kajo was opened in Solin. Besides Sveti Kajo, Cemex Croatia now has two other plants in the country, all three within 10km of each other. Due to their close proximity, Cemex Croatia now considers the three plants as one plant with three kilns.
Sv Kajo, Solin
The Sv Kajo site began operations in 1904. The plant has a 1400t/day KHD four-stage preheater kiln with no calciner, one main burner and a Claudius Peters grate cooler. Sv Kajo is one of Cemex's most energy-efficient cement plants, with amongst the lowest energy requirements in the world; Marijan Vuko, cement operations director, explained that he hopes it will be the second-most energy-efficient in 2015. This is due to the implementation of best practices and close collaboration with the Cemex Research Group in Switzerland and Mexico. The Sv Kajo site also has a 120t/hr raw mill, a 70t/hr cement mill and four cement silos, each with 6000t of cement capacity. Up to 4500t/day of cement can be shipped in bulk from the site by truck, train or ship, while 3000t/day of clinker can be dispatched in bulk by truck. Besides Ordinary Portland cements (OPC), Sveti Kajo also has the API 10A Monogram License for oil well cement Class G.
Sv 10 Kolovoz, Klis, Split
The Sv 10 Kolovoz site began operations in 1908. It is Cemex Croatia's smallest cement plant and is currently mothballed due to poor market demand. It has a 1180t/day KHD four-stage preheater kiln with no calciner, one main burner and a Claudius Peters grate cooler. It also has a 110t/hr raw mill and two cement mills, with 10t/hr and 40t/hr of cement production capacities. The Sv Kajo site has four cement silos, each of which can store 3000t of cement. When the site is operational, cement is dispatched in bulk by truck at a maximum rate of 1200t/day and 3000t/day of bulk clinker can be dispatched by truck.
Sv Juraj, Kaštel Sućurac, Kaštela
The Sv Juraj plant began operations in 1912 and is Cemex Croatia's largest site. It has a 3100t/day Polysius Dopol kiln that dates from 1979. It is Cemex's most energy-efficient with regards to specific heat consumption in the world. The kiln has a four-stage preheater and a riser duct, but no precalciner. It has a 70m-long Claudius Peters grate cooler with a high-efficiency static part to improve thermal efficiency, which was installed in 2003. Sv Juraj also has a 235t/hr raw mill and two 120t/hr cement mills. There are four cement silos, each with 12,500t of capacity.
Sv Juraj is the only one of Cemex Croatia's sites with bagging facilities: It has two palletisers, one by Beumer Group and one by Möllers Group. As such, 6600t/day of bulk cement can be dispatched by ship or truck and 3000t/day of bagged cement can be dispatched by truck, train or ship. 2640t/day of big-bag clinker can be dispatched by ship, truck or train and 5000t/day of bulk clinker can be sent by ship or truck.
While all of Cemex Croatia's sites have achieved ISO 9001, ISO 14001 and OHSAS 18001 certifications, the Sv Juraj plant is also API Q1 certified for oil well cement production.
Products
Cemex Croatia manufactures seven standard products across its three sites:
- CEM I 42.5R
- CEM II/B-S 42.5N
- CEM II/B-M (S-LL) 42.5N
- CEM II/B-M (S-LL) 32.5N
- CEM III/A 42.5N LH
- CEM III/B 32.5N SR LH
- Concrete filler
It also produces special cements, including Class G oil well cement, on a campaign basis. Cemex Croatia's first trial of oil well cement production took place in 2013. A sample was sent away for testing and the plant duly achieved its API 10A Monogram License and API Q1 certification. During Global Cement's visit to Sv Juraj, Cemex Croatia's first oil well cement order (3000t), which was placed in September 2014, was being completed. New oil well cement contracts are under negotiation and are expected to be bigger.
Raw materials
Cemex Croatia supplies all of its sites with raw materials from one quarry, which is located nearby between the kilns and the Kozjak Mountain. The quarry is world-famous for the quality of its raw material. In the 19th Century the material was extracted and shipped to Italy for cement production. At the time, no correctives were needed for cement production as the composition of the raw material was ideal. This was simply ground pure to produce raw meal. The presence of these raw materials is why cement production began so early in this part of Croatia.
Although the 'perfect' raw material has now been depleted, the existing material is still excellent quality. Less than 2% of correctives are required for clinker production. Cemex Croatia tries to keep its suppliers as local as possible: Aluminium oxide, high-grade limestone and gypsum are sourced within Kaštela, but iron additives are imported from Spain.
With regards to alternative raw materials, Cemex Croatia uses around 200,000t/yr of granulated blast furnace slag (GBFS), which it imports from Italy. It is necessary to import as the quantity available locally is small and its quality is low. Cemex Croatia is also considering the use of fly ash to further reduce the clinker factor of its cement in the next 1-2 years. According to Vuko, the company is continuously seeking alternative raw materials at reasonable prices.
Cement production process
Cemex Croatia's cement production process is fairly typical of the global standard within the cement industry. The raw material is homogenised at the quarry using the Chevron method (with 800 layers) and transferred around 1.5km to the kilns via belt conveyor (Figure 1). Around 5400t/day of raw material is transported from the quarry to both of the active sites. At the Sv Juraj site (Figure 2), the raw material is ground in the 235t/hr capacity raw mill, before being transported to the homogenisation silo (Figure 3). The materials are calcined in the 3100t/day Polysius Dopol kiln (Figure 4) and the resulting clinker is conveyed to one of the 120t/day cement mills for grinding (Figure 5). The cement is stored in one of four 12,500t capacity cement silos.
Cemex Croatia's Sv Juraj and Sv Kajo sites have been running at >90% capacity utilisation since 2009: Sv 10 Kolovoz has been closed since 2009. Cement production is continual at Cemex Croatia's active sites, with an annual winter maintenance shut down that lasts around 25 days. During the most recent winter shut down at the Sv Juraj site in February 2014 the kiln refractory and kiln tyre were replaced, while other small maintenance projects were also completed. In the most recent shut down at Sv Kajo, which took place in December 2014, a static part was installed at the existing Claudius Peters grate cooler. This should elevate energy-efficiency to the same level as the Sv Juraj kiln.
Vuko explained that the production of oil well cement differs from Ordinary Portland Cement (OPC) in a number of ways. The characteristics desired from OPC are the opposite to those desired from oil well cement: oil well cement needs to have as little reactive clinker as possible to delay its set time, while OPC needs to be highly reactive.
As such, oil well cement production requires different proportions of raw materials, as well as different proportions of different additives. The oil well cement clinker is ground and stored separately, using the same equipment, but with different technical parameters. Unlike OPC clinker, after the oil well cement clinker has been ground in the raw mill, it must be left to cool to ambient temperature from around 100°C. Vuko explained that at the Sv Juraj site, there is a 15 - 20 day delay between the cooling of the clinker and it being ground in the cement mill, as the clinker temperature is of the utmost importance for the production of top-quality oil well cement.
As oil well cement customers pay a premium price, they expect a premium product and each has a different set of required product specifications. Most customers require the use of their own additives for oil well cement production. It is not always enough for the customers to be able to test the oil well cement in their general laboratories: Some need to run site-specific tests to probe the reaction of the retarder additives. The site-specific tests enable Cemex Croatia to update their production process and additives as required. In addition, some customers require small batches of oil well cement over several months, rather than a continuous supply. It is very important that the product is consistent between batches.
Quality control
Each of Cemex Croatia's sites has its own process control room, which monitors the entire production process, from quarry to end product and emissions. Employees staff the control room in three shifts that total 24 hours.
Sv Juraj's quality control has all of the necessary product control systems, including X-ray fluorescence (XRF) analysers, online analysers and optical microscopes. The department ensures that the products comply with European standard EN197 Part 1 and API 10A (for oil well cement). Raw materials, additives, fuels, clinker and cement products are all expertly prepared and examined (Figure 6).
Cemex Croatia also has its own oil well cement lab, which has additional equipment due to the need for more stringent quality control. One particularly important piece of equipment is the optical microscope. The oil well clinker sample is placed inside a piece of epoxy resin, which is then cut, polished, etched and studied via optical microscopy (Figure 7). The larger clinker crystals (in comparison with OPC clinker) shown on the monitor are indicative of low-reactivity clinker, as desired for oil well cement. In addition to its standard testing, the lab also provides reports for special customers.
Fuels and energy
Traditional fuels
More than 90% of Cemex Croatia's fuel is Spanish petcoke, which is processed in a 25t/hr capacity mill. For the kiln start up, heavy oil is used. Small quantities of low-sulphur coal are used during general kiln operations to reduce the sulphur levels, as >6% sulphur content is bad for the kiln. The coal was, until recently, imported from Ukraine. The supply chain is more complex now due to the political instability.
Alternative fuels
In contrast with much of Europe, Cemex Croatia's alternative fuel use is very low. The Sv Juraj kiln has used 3% of waste oil at the main burner since 2003. Since 2012, Sv Juraj has also used waste residue produced from the local production of olive oil within 100km. Up to 5000t/yr is used at the kiln inlet chamber. The waste residue is only produced during the olive harvest season in October - January each year. The slurry residue is pumped to the riser duct using an adapted concrete pump. It has around 50% moisture content and a calorific value of 3900kCal/kg. Its use is one of Cemex Croatia's contributions to the environmental well-being of the local community. Prior to being used as an alternative fuel, the waste residue was illegally landfilled.
One of Cemex Croatia's biggest plans for 2015 is the implementation of a higher alternative fuel substitution rate. The Sv Juraj kiln is already able to use solid recovered fuel (SRF), waste biomass and wood chips at the main burner and has the required environmental permit for up to 10t/hr. The SRF will be delivered via moving floor trucks and will be stored in a 550m2 silo, which is enough for eight hours of operation. The silo will feed into a Di Matteo alternative fuel conveying system, which will transport the waste into the main burner of the kiln (Figure 8).
According to Vuko, implementing a higher alternative fuel substitution rate will be a challenge for the company, as Croatia's waste management supply chain is extremely undeveloped and there are currently no significant quantities of alternative fuels available on the market. However, the Landfill Directive that bans all waste landfilling will come into effect in Croatia in 2018 and the government is responding accordingly. In 2015, two waste treatment centres are due to be completed in Croatia, although they will both be located too far from Cemex Croatia to be a viable source of SRF. However, these are just the first two waste treatment centres of many. A nearby centre has been planned, although as construction has not yet begun it is unlikely to be completed before 2017. As such, while Cemex Croatia's alternative fuel substitution rate should increase in 2015, it is unlikely to reach the maximum permitted 10t/hr rate at the Sv Juraj kiln until 2018, when more local SRF is expected to be available.
Aside from availability, the main limiting factor when it comes to Cemex Croatia's alternative fuel substitution rate is its chloride content. The Sv Juraj kiln has no chloride bypass and does not plan to install one, as the bypass dust must then be disposed of. It cannot be legally landfilled, so financially it makes no sense to install one. Currently the only option with regards to quality and availability is to import alternative fuels, although it is currently financially unviable to do so.
There is significant opposition to the implementation of alternative fuels from the local population, particularly from Kaštel Sućurac. According to Vuko, the locals inhabitants are not well-educated regarding the advantages of their use. The main concerns include dioxin, heavy metal and mercury emissions. In response to the protests, Cemex Croatia has organised excursions for journalists, educational authorities, non-governmental organisations (NGOs) and prominent local figures to other Cemex plants in Europe to provide a better understanding of the benefits of alternative fuels use. It has also organised local conferences and meetings in town halls and universities and has published the Environmental Assessment study that it was obliged to produce in order to gain its 10t/hr permit for alternative fuel use. However, the response to Cemex Croatia's efforts have been poor, with few taking part in the initiatives.
Energy-efficiency
Although it has considered the use of waste heat recovery (WHR), Cemex Croatia has concluded that it is currently financially unviable. There are no subsidies available from the government and the ambient climate in the region means that it would not make sense when current electricity prices are considered. However, if subsidies for WHR systems came into place, WHR systems prices fell or electricity prices rose, Cemex Croatia would reconsider their implementation.
Despite the lack of WHR system, Cemex Croatia does produce a portion of its own electricity via a solar panel project in its quarry. The panels generate 300kW of electricity and are positioned in the quarry to maximise solar exposure.
In another initiative to increase the energy-efficiency of Cemex Croatia's operations, many of the large motors spread around the Sv Juraj and Sv Kajo sites have been replaced with smaller and more energy-efficient motors. This project is still ongoing and is due for completion in 2015.
Emissions
Cemex Croatia takes emissions very seriously. Each of the sites has its own automatic emissions monitoring station. While many emissions are measured continually, other emissions, such as polychlorinated biphenyls (PCBs), heavy metals, dioxins and furans are measured six times per year. It is the only cement producer in Croatia that makes its live emissions levels publicly available on its website:
http://www.cemex.hr/Naseemisije.aspx
The data includes CO, SO2, NO2, HCl and dust emissions at the main stack, the cooler and the coal mill stack. Mercury emissions will also soon be added to the live data. According to Vuko, Cemex Croatia currently exceeds the emission limits on CO2, but the only way to reduce its levels are to increase its alternative fuel substitution rate, an ongoing challenge.
The Sv Juraj site has had a selective non-catalytic reduction (SNCR) system installed since 2011, while the Sv Kajo site has had an SNCR system since 2012. Both systems use urea to reduce NOx emissions instead of ammonia. Currently the NOx emission limit is 800mg/m3, but this is set to fall to 500mg/m3 in 2016. Vuko expressed confidence that Cemex Croatia would be able to meet the new emissions limits by increasing its urea consumption, although related costs would increase again. Urea costs have already risen in recent years following the introduction of waste oils and residues as alternative fuels, which increases NOx emissions at the sites.
All of Cemex Croatia's sites use large bag filters on the kiln and the outlet cooler, in addition to smaller bag filters at the clinker silo, the cement mills and at other strategic positions. Bag filters are used to reduce dust emissions to within the necessary range wherever needed.
Noise pollution has been a big challenge for Cemex Croatia as the areas around all of the kilns are highly-populated. Noise must be kept below 65dB during the day and below 50dB at night. Great efforts have gone into addressing this. Noise sources at the cement sites have been located using seismic monitoring systems. The fans, compressors, cement mills and stacks were identified as the key contributors to noise pollution. In 2015 silencers will be installed at all of the offending locations. Quarry blasting is another source of noise pollution. To prevent disruption to the local inhabitants, Cemex Croatia uses seismic monitoring equipment during the blasting to ensure that the noise emissions remain below its own maximum levels, which are stricter than those required by the government. Quarry blasting and other activity is monitored from the central control department.
Market and distribution
Cemex Croatia dispatches via truck, rail and ship, depending on the product and customer location. The Sv Juraj site sells both bagged and bulk cement, unlike Sv Kajo and Sv 10 Kolovoz, which have no bagging facilities. Bagged cement comprises 20 - 25% of Cemex Croatia's sales, although this value falls each year. Bagged cement is sold mainly to retailers, while construction companies and ready-mix producers, who comprise the bulk of Cemex Croatia's customers, purchase bulk cement.
The local market
Cemex Croatia considers itself the market leader in Croatia and Montenegro. It is also a strong player in Bosnia. CEM II and CEM III products are mainly sold to the local market, which according to Vuko, includes Croatia, Bosnia and Montenegro due to the terminals Cemex has in those countries.
In Croatia, cement and clinker usually travels by truck, although products destined for the capital city of Zagreb are usually dispatched by rail. Within the country, Cemex Croatia competes with Holcim Croatia's 0.75Mt/yr capacity Koromačno plant and Nexe's 0.6Mt/yr capacity Nasicecement plant in Nasice, both of which are situated far to the north.
The Croatian cement market has less extreme seasonal fluctuation than other countries due to its moderate winter temperatures. However, in the summer months construction at the coastal areas is banned for the tourist season, so domestic sales fall. Likewise, from 15 December to 15 January, domestic sales plummet, particularly in the north of the country, where the temperatures are much lower. During these periods of low domestic demand, exports increase to make up the shortfall.
As for much of Europe, the Croatian economy was badly hit by the financial crisis in 2008 and has yet to recover. Cemex Croatia's smallest site, the Sv 10 Kolovoz site in Split, has been out of operation since 2008 due to poor market demand. Vuko does not expect it to re-open in the near future. Croatian construction is falling each year and is not expected to improve in 2015. An increase in construction rates and thus the domestic cement market could be seen in 2016, but that depends largely on the level of government infrastructure investments.
The export market
The export market is very important to Cemex Croatia; around 50% of its cement is sold to the Mediterranean regions, from Africa to Italy. For exports to these regions, cement and clinker usually travels via ship from the Sv Juraj port (Figures 9 and 10), which looks out over the bay of Kaštel Sućurac. The products are often sling-packed for easy transit to the ship by crane.
The export market is currently very sensitive due to political instability in Libya and Egypt. Export volumes were very strong in the first six months of 2014, but then the instability started and export volumes fell dramatically. The future well-being of the export market depends largely upon how long it takes the countries' political landscapes to stabilise.
Although Cemex Croatia's first oil well cement order was for a domestic customer, it has high hopes for oil well cement demand on the export market. Local demand is very limited, as there are no big oil operations or servicing stations in the Adriatic Sea, "Unless the government finds a big quantity of oil in one of its ongoing offshore explorations," Vuko added. He added that, as it is a very closed market, it can be hard to estimate demand.
Overall, in 2015, Cemex Croatia hopes to increase its export market through higher sales of OPC and oil well cement, retain its domestic market and keep both of its currently-operational sites running with high capacity utilisation rates.
Environmental and social responsibility
As for the rest of Cemex Group, Cemex Croatia takes its environmental and social responsibilities seriously. It regularly runs open days in cooperation with local primary schools as part of an outreach programme to educate and be actively involved with the public. After one such day, the children were encouraged to express their experiences through pictures, which were then transposed onto a board that is displayed at the Sv Juraj entrance (Figure 11).
Cemex Croatia has depleted part of its quarry and has since rehabilitated the area, planting an olive grove (Figure 12). More than 1000 olive trees have been established, which were being harvested to produce extra virgin olive oil during Global Cement's visit. It is the biggest oil grove in the area and Cemex Croatia's employees are very involved in its care and maintenance.
