quadropol® vertical roller mill
thyssenkrupp is one of the few full-range suppliers for the cement industry – from individual machines, all the way up to complete cement plants, and this since decades. The market requirement is easy to define. Present kiln lines have capacities of up to 10,000 tons per day. Kiln lines of 12,000 tons per day were already built by polysius® technology.
International Cement Review January 2020polysius provided the latest equipment technology for the plant and as a result the Oruro works is one of the most modern cement facilities in Latin America.
„The making of Oruro“ by Cementos de Bolivia and PEC Consulting Group, USA
The quadropol® - advantages at a glance
Lower construction costs
Easier maintenance
Lowest level of vibration (< 2.0 mm/s)
Highest level of digitalization
Extract of our references
Cemento de Bolivia
Cementos de Bolivia ordered a 3,000 tons per day kiln line, successfully commissioned in 2019. This was an EPC contract to the German-Spanish polysius-Imasa-Valoriza consortium. The contract included a QMR² 38/19 for raw grinding and a QMC² 45/23 for cement grinding.
After the shortest time, the plant was able to meet the project’s design parameters, fulfilling all process/technical guarantees.
Please also refer to: Vilaseca, M, PEG Consulting Group LLC, USA. “The making of Oruro”. International Cement Review (January 2020)
Cementos Cibao S.A.
Cementos Cibao S.A., cement producer in the Dominican Republic, continues the modernization process and ordered a cement mill type QMC² 40/20 for grinding different cement types. Compact plant arrangement with service tower, quadropol® vertical roller mill and main filter are part of the supply. Optimized mill operation will be supported by a digitalization package incl. intelligent mill controller.
The mill is operating very successful since mid of 2021.
The quadropol® concept for coal or pet coke grinding, with adapted table speed and high efficiency separator sepol®, ensures a safety mill operation and serves reliable the kiln burning process.
Mombasa Cement Ltd. ordered a QMK² 24/12 with three roller units for the 5,000 tons per day kiln line. In addition, the raw material grinding process will be supported by a QMR² 48/24.
For the 4,000 tons per day kiln line Shiva Cement Ltd. contracted a quadropol® vertical roller mill for grinding pet coke with a QMK² 32/16.
The same mill size QMK² 32/16 is running in Indonesia for years now, grinding and drying lignite.
Yamama
Yamama Cement ordered two 10,000 tons per day kiln lines. For raw material grinding four QMR² 48/24 are contracted, while for cement grinding four polycom® high pressure grinding rolls as a combi grinding system are considered due to material properties.
The four mills are operating very successful since mid of 2021. The final set-up of the mills resulted in good operation performance. The material feed moisture is 2.61 %, which means it is fairly dry. At the end the injected water quantity, required on the table during operation, is only 0.78 %.
Please refer also to: thyssenkrupp “A holistic approach“. International Cement Review (September 2021)
The installed 4,000 tons kiln line at Afyon Cimento is successfully in operation for many years, showing truly equipment reliability and stable plant performance. For raw material grinding a quadropol® vertical roller mills QMR² 45/23 was contracted to serve the kiln line, while for cement grinding two identical QMC² 45/23 were considered for grinding different cement types. The request for interchangeable parts for the three mills was fulfilled and represents still a holistic approach. For coal grinding a QMK² 32/16 completed the grinding portfolio.
The cement mills are equipped with high efficiency separators to achieve cement qualities with a fineness up to 5 000 cm2/g acc. to Blaine.
Cemento Progreso, Guatemala, 4500 tons per day plant incl. QMR² and QMC²
When developing and designing the machinery for the cement industry, it is necessary to create a technically viable solution to meet the market requirements. Besides a general feasibility study, and further development as well as optimisation of the design, this calls for an intelligent design approach encompassing. This includes a simple mode of operation as well as economic and desired product aspects.
Today the capital expenditure (CAPEX) for plant operators is generally very high and it is thus only natural that high availabilities need to be achieved. Vertical roller mills are an essential part within the production process for grinding raw material (QMR²), coal (QMK²) and increasingly binding agents or slag (QMC²/QMS²).
At the end the cement quality is important to serve the market. Finally, the raw mill product is the supplier for the kiln, means also responsible for the clinker quality. A technical reliable solution within the production process includes our sepol® high efficiency separator to ensure the desired product fineness for all applications. For raw grinding our new developed HDZX double cyclones are part of the technical solution and includes latest process know-how.
The spotlight has also turned on operating and maintenance costs (OPEX). The energy consumption of a mill, as well as of the entire grinding system or section, plays a significant role in decisions made by plant operators. Maintenance work, which includes inspection, servicing, repairs and improvement, is a cost driver and needs to be taken into account.
Vertical roller mill – digital solutions and services
In recent years, thyssenkrupp Polysius has successfully continued step by step the development process for the quadropol® vertical roller mill concept. This compact and modular concept includes the latest market requirements regarding compact plant layout, efficient operation and reliable machine design. Moreover, it also reduces unscheduled downtime. Tailor-made solutions with interchangeable parts are also available. The topic digitalization is being pushed ahead and part of the current design. Digital solutions help to find the optimum operating conditions for your cement plant.
thyssenkrupp Polysius offers additional solutions and services:
polysius® grinding plants – a holistic approach
The development and, in particular, the enhancement of the quadropol® concept incorporates the requirements of the market and is subject to a continuous development process.
Cemento Progreso, Guatemala, 4500 tons per day plant incl. 2 x QMC² 51/25
The roller unit has a very compact design, is fully pre-assembled in the thyssenkrupp proprietary workshop and is the final component to be installed. The vertical roller mill design calculation considers efficient comminution, longevity and highest reliability. The reduction in mechanical components in itself decreases here the probability of failures.
Assembly and adjustment of the mill components is reduced to a minimum in order to shorten the erection time and save costs. The weight of the four preassembled roller units of a medium sized mill is approx. 50 % of the total weight of the mill components and separator. This lowers the total effort regarding assembly, alignment, welding and reduces the total cost of erection. At the same time the erection process will be faster.
The hydraulic system is also smart and compact; one hydraulic unit serves for the four roller units. The grinding force for comminution is generated solely by one hydraulic cylinder per roller unit. This concept also requires only one piston accumulator to act as the spring system. The fixed bearing is maintenance-free, and although the roller bearing is located in the mill, it is fully capsuled without any shaft sealing inside the mill. As no dust can get in, there is no longer any need for a sealing air fan. Accessibility is excellent and it is possible to carry out small maintenance work easily without the necessity to remove the roller unit. The design and working principle or operation principle of the mill are shown here in an animation.
In particular vibrations in the grinding plant are of crucial importance. The using of reinforced concrete pylons for the roller units has a big benefit, apart from easier civil work and cost, the vibrations level is much lower due to the good damping characteristic. During unstable operation all loads are transmitted to the foundation in vertical direction. Components such as the stopper are arranged in an intelligent way, the stoppers are arranged in the effective direction of the hydraulic cylinder. The vibrations need to be avoided in order to protect the mechanical components of the grinding plant. The focus here is not on the vibrations of the gear unit base, as these are approx. 0.5 mm/s in vertical direction only. Rather, it is important to detect the vibrations caused by the grinding process. For this purpose, a sensor is installed in each tension frame of the roller units, namely at the level of the grinding bed. In nearly all installed mills, the vibration value due to the efficient grinding process and foundation solution is less than 2 mm/s in horizontal direction and this sets still the benchmark. The low vibration level demonstrates the smoothness of the running mills and the operational continuity as well as longevity.
The design philosophy is for all applications the same and part of the holistic approach. For coal or pet coke grinding a safety concept must be considered to protect persons and machinery who work in hazard areas. ATEX is therefore a non-negotiable point in the process installation. All directives need to be carefully fulfilled and part of the design of our coal mill QMK².
Being able to schedule maintenance work in advance is the key to high availability. Unforeseeable major downtimes need to be avoided where possible. A higher level of digitalization is therefore a must. A monitoring system, integrated into our data management system, is a standard feature in quadropol® vertical roller mills. In addition to the analysis of the operating data and evaluation by the experts, the mill operation can also be automated. The so-called Advanced Mill Control (AMC) continuously adjusts the control parameters to the targets set by the plant operator. Parameters are set automatically and in small increments, but at a higher frequency compared to manual mode, so that an improved mill operation is possible. The AMC assists the mill operator in achieving higher average throughputs over a longer period of time combined with less average specific power consumption. The threshold values of the machine are monitored and kept within the permissible loads. This prevents the machinery and machine components from being overloaded. The mechanical data as well as the process data are recorded and processed using state-of-the-art data analytics tools for pattern recognition and then analysed by our team of experts. This includes actual evaluation of the operating data, assessment of the condition of the components and mill operation, as well as recommendations on process, servicing and maintenance strategies. Also, timely planning and delivery of spare parts is included. A full 360-degree service concept is rounded off by on-site support of mill operators by thyssenkrupp specialists.
Why choosing the quadropol® concept?
Compact plant arrangement
approx. 50 % pre-assembled of mill & separator
Lowest down time due to mechanical simplification
Less assembly, less alignment, less welding results in reduction in total costs
Simple hydraulic system with only one piston accumulator, one roller bearing, no confining air
Roller lubrication with one lubrication pump, return flow by gravity
Lowest market vibration level < 2 mm/s (measured horizontal at location of comminution)
Vertical roller mill gearbox forces only in vertical direction due to arrangement, vibration level < 0.5 mm/s
No extensive scaffolding necessary for maintenance work, considering OSH regulation
Changing roller tyre within two shifts on pylon
Highest mill compound availability and reliability
Efficient grinding – low specific power consumption
System Monitoring and Advanced Mill Controller implemented
Stable operation and process monitoring/control
Digitalization incl. AMC and state-of-the-art data analysis
etc.
International Cement Review January 2020This state-of-the-art equipment enables the staff to monitor and control all process variables in real-time. (...) As shown the plant is able to deliver a stable process and supply a high-quality product.
„The making of Oruro“ by Cementos de Bolivia and PEC Consulting Group, USA