The specific selection function effect on clinker grinding efficiency in a dry batch ball mill

Dry grinding experiments on cement clinker were carried out using a laboratory batch ball mill equipped with a torque measurement. The influence of the ball size distribution on the specific selection function can be approached by laboratory runs using mono-size balls. The breakage is more efficient with maximal specific selection functions at the initial size reduction stage. But, in terms of cement finish grinding all stages of grinding are determinant for the production of a required Blaine surface area (3500 cm2/g). So, the choice of ball size according to a maximal specific selection function leads to an increase of the energy consumption. In addition, investigations on the mono-sized fractions and on the crude material (size minus 2.8 mm) demonstrate that the energy efficiency factor can be optimized using ball size corresponding to relatively low specific selection function

Energy efficiency of cement finish grinding in a dry batch ball mill.

Dry grinding experiments on cement clinker were carried out using a laboratory batch ball mill equipped with torque measurement. The specific energy was found to be dependent on operating parameters and clinker environment. Additional compounds such as gypsum and pozzolanic tuff improve energy efficiency. The optimal parameters allowing maximising the energy efficiency factor were determined. Energy efficiency factors were obtained both on the crude material (size minus 2.8 mm) and on a sieved fraction (1- 0.71mm). They demonstrate that a low initial rate of breakage implies higher energy efficiency. On the contrary, conditions ensuring an initial maximal rate of breakage lead to an increase of the energy consumption

Modélisation d’un préchauffeur à cyclones d’une cimenterie et analyse des pertes physico-chimiques d’exergie

Un modèle du préchauffeur à cyclones d’une unité de ciment est développé sur la base de données recueillies sur une installation industrielle comprenant quatre étages de cyclonage avec des alimentations à contre-courant de gaz chaud et de farine crue servant à la fabrication de clinker. La division du préchauffeur est modélisée par une cascade de mélangeurs parfaits avec reflux de solide afin d’évaluer la quantité de poussières quittant chaque étage. Les pertes d’exergie associées au transfert thermique et à la réaction principale liée à la décomposition du CaCO3 sont analysées sous différentes conditions opératoires. Les résultats montrent que la température du gaz à l’entrée du préchauffeur et le nombre d’étages des cyclones ont une influence très significative sur les pertes physico-chimiques d’exergie. L’intensité de l’irréversibilité de la réaction de décarbonatation reste peu significative comparée à celle de l’échange thermique

Optimal Energy Integration and Off-Design Analysis of an Amine-Based Natural Gas Sweetening Unit

peer reviewedThe present paper focuses on the efficiency enhancement of the energy-intensive natural gas (NG) sweetening process in the context of upstream natural gas production. A bi-level heat integration scheme is proposed including direct recycling of available high-temperature waste heat and harnessing the excess low-temperature waste heat in an optimized organic Rankine cycle (ORC) for power production. The energy performance of the whole model was studied under a range of possible reservoir conditions. A particle swarm optimization (PSO) algorithm was adopted to simultaneously optimize the parameters of the heat recovery network as well as the ORC cycle parameters. Finally, in order to account for the impact of perturbations of the heat source and sink, an off-design performance analysis was conducted using real-time data from an industrial plant. The proposed integration methodology was found to be effective across most of the reservoir conditions covered in this study. At optimal integration, a reduction of 40% up to 100% in heating requirements of the amine process was reported, as well as a net electricity production of 30% up to 190% of the electrical demand of the background process. The use of propane (R290) as a working fluid resulted in the highest energy output, whereas higher carbon number fluids allowed a better energy/working pressure trade-off. The off-design analysis allowed for the quantification of the impact of operational fluctuations of the background process on integration performance. Energy savings resulting from direct heat integration were found to range from 68% up to 103% of the expected design value, whereas the ORC net energy output respective to the use of R290, R600a, and R601a was found to range from 60% to 132%, 47% to 142%, and 52% to 135%.PROCURA projec

Impact of Surface Treatment of Flax Fibers on Tensile Mechanical Properties Accompanied by a Statistical Study

In this work, a surface treatment with sodium bicarbonate (NaHCO3) at different concentrations of 4 and 8% is applied to the surface of the flax fiber for a period of 80 hours at room temperature. The purpose of this study is to observe the effect of different treatment processes on the flax fiber, i.e. on its mechanical properties such as: stress and strain at break and Young's modulus. A major test campaign of more than 240 tests is carried out. Due to the variability of the plant fibers, more than 80 samples were tested for each group at a gauge length (GL = 10 mm). The results of the quasi-static tensile tests have a large dispersion which makes it possible to measure the degree of variability in the stress and strain deformation and the Young's modulus of the fiber. This degree of variability has been studied by means and statistical tools such as the Weibull distribution at two

Heat Exchange Modeling of a Grate Clinker Cooler and Entropy Production Analysis

The concept of the exergy analysis is applied to a grate cooler of a cement production facility. The cooling of the clinker is modelled by a gas-solid series of cross-current contacting stages fully mixed for the calculation of the temperatures of the clinker and the air with their thermodynamic properties along the cooler. The equation of the production of entropy developed in the case of this representation reveals various adimensional parameters. The study of the sensitivity of the entropy generation number by tests of simulation in real operating conditions of the cooler shows the importance of the inlet temperature ratio and the number of stages cross-current contacting

Effect of solvent concentration on the energy demand of an absorption-based natural gas sweetening plant

Amine-based chemical absorption is the most advanced CO2 capture system. Yet, high energy requirement is a major hinder to its wide deployment. Among the possible routes of improvement is the use of novel amines that can achieve the trade-off between robustness and low regeneration energy. Our work investigates the use of MDEA/DEA as solvent for the capture of CO2 from natural gas. The presence of BTEX (Benzene, Toluene, Ethyl Benzene and Xylene) in the raw natural gas was taken into account. AspenHysys v9 was used to simulate the chemical absorption system. The impact of solvent composition on key process variables, the required flow rate to achieve transport specification, required reboiler duty, pumping energy, BTEX incineration energy and amine losses, were studied. The optimal operating point corresponding to the lowest energy requirement was identified and the separate contribution of each process parameter was estimated

New approach for computer-aided static balancing of turbines rotors

The balancing operation consists in improving the distribution of the rotor masses so that the free centrifugal forces around the rotor axis, imposed by the manufacturer, do not exceed the tolerances allowed by the standards. In this paper we propose algorithms for the distribution of the turbine blades from data from an electronic scale which allows to measure the static moment of the blades, these algorithms aim to find the correction weight and the angle of position of the correction mass, we also propose a simulation of the distribution of the blades of a turbine to get an idea on the assembly. This operation is necessary in the case of a repair of the rotors or in the assembly of the new flexible rotors. Using a MATLAB calculation code