Vertical Roller Research Articles

Selection of sustainable juice extraction techniques for non‐centrifugal sugar industry using multi‐criteria decision‐making methods

AbstractNon‐centrifugal sugar (NCS) industry is one of the oldest small‐scale cottage industries in India, with crude and inferior production techniques. Toward transforming these inferior techniques for the sustenance of NCS industry, it is necessary to select sustainable methods among the existing technologies at various stages in the production process. In the production of NCS, juice extraction is the primary and essential process. The present article gives an insight in selecting a sustainable juice extraction technology using various decision approaches. Analytic hierarchy process (AHP) integrated multi‐criteria decision‐making (MCDM) is the decision approaches used for selecting the appropriate juice extraction technique among 6 alternatives based on 11 criteria covering various sustainable factors. Through this MCDM approach, it was obtained that crusher with single horizontal roller that uses electrical motor without any usage of hot water is the most sustainable juice extraction method for NCS production in plant mode with 1.38 group priority weight. On the other hand, crusher with single vertical roller that runs on electrical energy without usage of hot water and crusher with single horizontal roller that runs on diesel engines without the usage of hot water is a comparatively least preferred alternative for NCS production with 3.33 and 3.39 group priority weight, respectively.Practical Applications This article narrates the novel work undertaken to identify a sustainable crushing technology for extracting sugarcane juice to produce non‐centrifugal sugar. The analysis is carried out to select the most appropriate technology among 6 crushing technologies based on 11 evaluation criteria spreading across various aspects of sustainability. The analysis used three multi‐criteria decision‐making (MCDM) methods namely TOPSIS, PROMETHEE, and VIKOR. Based on this analysis it is found that single horizontal crusher that run on electricity without the use of hot water (SHEN) is the best juice extraction technology. Hence, this technology could be used by the non‐centrifugal sugar (NCS) industry to produce NCS in a sustainable way. Further, the methodology presented in this article, demonstrates the use of such methods to identify the better processes/subprocesses to produce NCS in a sustainable way.

Research on new beneficiation process of low-grade magnesite using vertical roller mill

Research on new beneficiation process of low-grade magnesite using vertical roller mill

A data-driven decision-making framework for online control of vertical roller mill

Vertical roller mill (VRM) is a large-scale grinding equipment, which is used to grind raw materials from block/granule into powder. Due to harsh production environment and inconsistent raw material quality, VRM requires timely regulation. Currently, the regulation of VRM is manually conducted; operators make decisions based on their observation and experience, therefore the timeliness and accuracy of regulation cannot be guaranteed. This study presents a data-driven online control decision-making approach; it extracts several key indicators for state judgment from the historical running state data, constructs a stable mode library based on clustering the running state, mines the association rules among variables, and establishes the rolling prediction model to predict the changes in the key indicators. In real-time operation, the target state is obtained by comparing the real-time state and stable mode library, and then the corresponding control strategy, composed of key indicators, controllable parameters and target state, is auto-generated to support the management of VRM operation. In this way, a closed-loop framework is formed based on offline data mining and online decision-making, supporting the operation optimization of VRM. This approach is applied in a cement plant as a case study in Jiangsu, China. The results show that the control strategy is effective in actual working conditions; the continuous operation of the equipment with vibration reduction is achieved.

Optimal Design and Force Analysis for Key Components of Vertical Roller Mill

Optimal Design and Force Analysis for Key Components of Vertical Roller Mill

Dual Adaptive Model Predictive Controller Application to Vertical Roller Mill Process Used in the Cement Industry

Diversified operating conditions, input-output constraints, and parametric variations in the Vertical Roller Mill (VRM) make it to have complicated dynamics and closed-loop instability. Existing traditional controllers are not superlative and may lead to an uneven plant shutdown. Model predictive controller with adaptive models can track these parametric variations and ensure the plant’s smooth running, which has been addressed in this paper. Data from the real-time VRM is acquired, and correlation analysis is carried out, which illustrates the use of outlet temperature and differential pressure as the output variables with tensile pressure and booster fan speed as the input variables. The base model for VRM is identified using the selected variables by data-driven system identification methods. The fourth-order state-space model was found to be optimal in capturing the dynamic behavior of VRM. Dual Adaptive Model Predictive Controller (DAMPC) is designed to handle each output variable individually. The use of DAMPC minimizes the complexity involved in the on-line parametric estimation for higher-order models by distributing the control authority to different controllers. The performance of the proposed DAMPC is compared with the existing Proportional Integral (PI) controller and Model Predictive Controller (MPC). Simulation experiments for reference tracking and rejection of slowly varying internal disturbances by considering parametric variations are carried out. Results illustrate DAMPC provides lesser overshoot and faster settling time amidst parametric variations.

Students making sense of motion in a vertical roller coaster loop

Describing the motion in a vertical roller coaster loop requires a good understanding of Newton’s laws, vectors and energy transformation. This paper describes how first-year students try to make sense of force and acceleration in this example of non-uniform circular motion, which was part of a written exam. In addition to an analysis of the exam solutions by about 60 students, a group interview was performed a couple of weeks later with four students, who had all passed the exam. The interview allowed the students to reflect on assumptions made and information missed.

Modeling and simulation of vertical roller mill using population balance model

Modeling and simulation of vertical roller mill using population balance model

Modelling of pilot scale vertical roller mill operated in overflow mode

ABSTRACT Pilot scale grinding tests were performed for various materials by a mobile unit for modelling studies. Vertical roller mill was separated into the two section as grinding and separation. Grinding operation was defined by population balance model and breakage rate was correlated with specific grinding force, material index determined by compressed bed breakage tests and surface area of grinding table feed. For the modelling of separation section, obtained data were fitted to efficiency curve approach and model parameters were back calculated. Relationships of these parameters with operational conditions were investigated. As a first model parameter by pass fraction of was correlated with dust load of the separator feed. Then, by pass fraction was defined as a function of the dust load of the separator feed and material density. The ratio of air speed and rotor speed was correlated with corrected cut size and density effect was reflected to the model.

A distributed PCA-TSS based soft sensor for raw meal fineness in VRM system

Vertical roller mill (VRM) is an increasingly popular comminution equipment in cement plants. Raw meal fineness at the outlet of VRM is one of the most important indicators to measure product quality. A soft sensing model developed for powder fineness in real-time could assist operators to monitor the comminution process online. However, due to frequent fluctuation of raw material properties, intrinsic nonlinearity of the process and changeable operation conditions, the data present a multimodal characteristic. Therefore, this paper proposes an indicator to measure the similarity between variables, that is, the shortest distance between nodes in the constructed weighted network. By combining the Girvan Newman (GN) algorithm, the nodes in the variable network are divided into multiple groups, and based on this, the distributed PCA (DPCA) similarity is adopted for time series segmentation (TSS). Compared with traditional similarities between samples (distance, density, etc.), the similarity between time series focuses more on the dynamic characteristics of variables. And the implementation of DPCA similarity is equivalent to increasing the sparse characteristics of principal components, which is beneficial for enhancing the generalization of the model. Support vector regression (SVR) models along with a support vector machine (SVM) based classifier are built to obtain final predictions of the powder fineness. Effectiveness of the proposed method is verified by actual industrial data. It has a root mean square error (RMSE) index of 0.3451 on the test set, which is much smaller than that of the multi-modal soft sensor based on either clustering approaches (0.6524) or PCA similarity based TSS method (0.4282).

Finite element analysis of the vertical roller mill based on ANSYS Workbench

By using of element analysis software ANSYS Workbench, the static analysis of lower rocker arm and column, and the modal analysis of column are carried out. The three-dimensional models of lower rocker arm and column were imported into the ANSYS Workbench for meshing. The loads and constraints were imposed on the meshed model to solve for the stress and deformation. The contour plots of stress and the total deformation of the lower rocker arm and column indicate that the structure meets the design requirements in strength and stiffness, which verifies the reliability of the structure. Through the modal analysis of column under free and constrained states, the first eight natural frequencies and vibration modals under free and constrained states are obtained, which can intuitively reflect the dynamic characteristics of the column itself, help to avoid structural resonances in engineering applications, and provide a theoretical basis for the optimisation design and fault detection of the column.

Finite element analysis of the vertical roller mill based on ANSYS Workbench

By using of element analysis software ANSYS Workbench, the static analysis of lower rocker arm and column, and the modal analysis of column are carried out. The three-dimensional models of lower rocker arm and column were imported into the ANSYS Workbench for meshing. The loads and constraints were imposed on the meshed model to solve for the stress and deformation. The contour plots of stress and the total deformation of the lower rocker arm and column indicate that the structure meets the design requirements in strength and stiffness, which verifies the reliability of the structure. Through the modal analysis of column under free and constrained states, the first eight natural frequencies and vibration modals under free and constrained states are obtained, which can intuitively reflect the dynamic characteristics of the column itself, help to avoid structural resonances in engineering applications, and provide a theoretical basis for the optimisation design and fault detection of the column.

Evaluating the influence of grinding method on the cement dispersion characteristics

Grinding methods of affecting the material being ground in a vertical roller mill and ball mill have fundamental differences. Subsequently, these differences have an impact on the dispersion of the crushed samples, the degree of defects in the surface of the grains, and as a consequence on strength characteristics of the ground products. This article studies the impact of the affecting method in the compared grinding units on the cement dispersion indicators.

Comparison of Various Models Implemented Using Linear and Non-Linear System Identification Methods for Cement Grinding Process Using Vertical Roller Mill

Comparison of Various Models Implemented Using Linear and Non-Linear System Identification Methods for Cement Grinding Process Using Vertical Roller Mill

Application of perfect mixing model for simulation of vertical roller mills

Vertical roller mills (VRMs) are well-established grinding equipment for various tasks in the coal and cement industry. There are few studies on simulation of VRMs. In this research work, application of perfect mixing model for simulation of a VRM in a cement grinding plant was investigated. Two sampling surveys were carried out on the VRM circuit. The samples and data from the first survey were used for the experimental determination of the breakage function and model calibration. The breakage distribution function of the material was determined by the compressed bed breakage test in a piston-die cell device. The model parameters were back-calculated using the feed and product size distribution data and the breakage distribution function. The model parameters obtained were used for simulation of the second survey and validation of the model. The simulation results showed that the simulated product size distribution curves fitted the measured product curves quite well.

Study on Optimization of Control Mechanism in Vertical Axis Wind Turbine

Objective-This paper describes an attempt to streamline the execution of the Vertical Axis Wind Turbines (VAWT) utilizing dynamic sharp edge pitch control. Methods/analysis- Aerodynamic model is chosen based on the surface profile and NACA 4-digit series was found to be the most suitable category under which NACA 0018 aerofoil design parameters have been chosen for the VAWT blade design, based on the previous research. The outline of wind turbine picked here is an H-sort Darrieus VAWT which deals with the lift drive of the wind. Findings- Active Pitch controlled VAWT with individual pitch control of each blade along with vertical roller bearings in the system is done to obtainmaximum coefficient of power harnessed from the wind turbine setup and increase the efficiency by 12.5%. Applications: The proposed design system is suitable for low wind speed areas which turbine is installed at lower heights.

Reliability assessment of the vertical roller mill based on ARIMA and multi-observation HMM

AbstractOnline running condition monitoring of the vertical roller mill (VRM) is significant to assess the equipment performance degradation and reliability. This paper proposes a performance reliability assessment method based on autoregressive integrated moving average (ARIMA) model and hidden Markov model (HMM) using the real-time sensing monitoring signals, which is designed to analyze the running state and predict the reliability of VRM. As most faults of VRM relate to hydraulic pressure of loading system and mechanical vibration, research on hydraulic monitoring and vibration monitoring is prerequisites, which determines the sensing parameters and monitoring points, provides the data base for following reliability assessment. Then ARIMA is applied to establish the performance degradation path using the historical sensing monitoring data. Finally, the multi-observation HMM is used to estimate the reliability changing trend of the equipment, the input observations of which are the predictive data from...

Operational parameters affecting the vertical roller mill performance

Vertical roller mills (VRM) have found applications mostly in cement grinding operations where they were used in raw meal and finish grinding stages and in power plants for coal grinding. The mill combines crushing, grinding, classification and if necessary drying operations in one unit and enables to decrease number of equipment in grinding circuits. Sustainable operations and proven benefits of the technology in cement grinding applications attracted interests of the mineral industry. Within the scope of the study, ore grinding performance of the VRM was investigated via a mobile grinding plant and relationships between operational parameters were identified. In this context, gold ore was ground under different process conditions. The samples collected after the test works and size distributions were determined. As a result of the study, effects of operational parameters such as working pressure, and classifier rotor speed on product mass flow and product size were investigated. In addition, correlations of specific energy consumption of the grinding-classifying circuit with product rate and product size are presented. The aim was to develop a VRM performance prediction model that is based on input data from characterization combined with the knowledge of the interaction of the single grinding parameters.

Evaluation of HPGR and VRM for dry comminution of mineral ores

The mining industry is searching for more energy efficient and dry comminution equipment as an alternative to conventional crushing followed by wet grinding circuits. This is a result of growing challenges associated with the increasing energy cost, scarcity of water resources and stricter environmental legislation. Dry comminution technologies, such as High Pressure Grinding Rolls (HPGR) and Vertical Roller Mills (VRM), have been successfully used in other industries such as cement and coal for decades, and the literature claims that these technologies are more energy efficient than conventional comminution practices. Pilot scale testing was conducted for each of these technologies using rock with properties similar to many mineral ores to test the claims in the literature and evaluate the applicability for hard rock mining operations. Whilst the test results for the HPGR and VRM are not directly comparable (due to different degree of size reduction), both demonstrated the potential for considerable energy savings compared to conventional ball milling. The HPGR and air classification circuit used 20 - 30 % less energy than the HGPR, screen, ball mill circuit. While VRM was estimated to use 10 - 30 % less energy (depending on the type of VRM) than a ball mill circuit for a similar degree of comminution.

Feasibility of Applying Clean Development Mechanism and GHGs Emission Reductions in the Gold Mining Industry: A Case of Thailand

Abstract There is presently overwhelming scientific consensus that global climate change is indeed occurring, and that human activities are the primary driver. An increasingly resource and carbon constrained world will continue to pose formidable challenges to major industries, including mining. Understanding the implications of climate change mitigation for the mining industry, however, remains limited. This paper presents the results of a feasibility study on the implementation of a clean development mechanism and greenhouse gases (GHGs) emission reductions in the gold mining industry. It draws upon and extends the analysis of a case study conducted on gold mining operations in Thailand. The results from the case study indicated that total GHGs emissions by company A were approximately 36,886 tons carbon dioxide equivalents (tCO2e) per annual gold production capacity that meet the eligibility criteria for small-scaled clean development mechanism (CDM) projects. The electrostatic separation process was found to release the lowest amount of GHGs, whereas comminution (i.e. crushing and grinding) generated the highest GHGs emissions. By scope, the emission from purchased electricity (scope 2) is the most significant source. Opportunities for CDM projects implementation in the gold mining sector can be found in employing energy efficiency measures. Through innovation, some technical efficiency and technological development in gold processing (i.e. high pressure grinding rolls (HPGR), vertical roller mills (VRM), gravity pre-concentration and microwave heating technologies) that have the potential to reduce energy use and also lower carbon footprint of the gold mining were further discussed. The evidence reviews found that HPGR and VRM abatement technologies have shown energy and climate benefits as electricity savings and CO2 reduction of about 8-25.93 kWh/ton ore processed and 1.8-26.66 kgCO2/ton ore processed, respectively. Implications for further research and practice were finally raised.

English

Design FMEA is structured method of identifying potential failure modes and providing corrective actions before first production run occurs. This paper aims to provide probable causes of failure, levels of effects of failure and corrective actions to be taken in the design phase for Bevel- Planetary Vertical Roller Mill Gearbox. Keywords—DFMEA, Bevel-Planetary Gearbox, Vertical Roller Mill, Risk Priority Number I. In tro d uct io n 1) Vert ica l Ro ll er M il ls: Vertical roller mills (VRM) are well accepted as most effectual means for grinding raw material in cement and power generation industry. These mills are driven by heavy duty gearboxes with horizontal input shaft and vertical output shaft (i). Generally, Bevel-Helical or Bevel-Planetary gearboxes are used for VRM. The gearbox is integral component of VRM as its output flange is rigidly connected with the mill grinding table. Fig. 1 shows the general arrangement of VRM with gearbox located at its bottom.