Granulation Unit Research Articles

Analyzing the Vibration Exposure to the Safety and Health at Workplace: A Case in the Urea Granulation Unit of the Fertilizer Factory

This study aims to evaluate the vibration exposure experienced by workers in the Urea Granulation Screen Unit (UGSU) at the fertilizer factory in Aceh, Indonesia. This study involved 30 labors in charge as operators, mechanical maintenance officers, electrical maintenance officers, instrument maintenance officers, and inspectors. The measurement of vibration was carried out using a Triaxial Accelerometer with Integral Magnet and shows that the vibration exposure on the factory floor of the urea granulation screen unit occurs vertically with a minimum value of 0.298 m/s2 and a maximum of 1.630 m/s2. According to ISO 2631-1:1997, the maximum vibration values that occur are categorized as a likely health risk zone and result in uncomfortable reactions to the workers. Furthermore, this study analyzes the effect of vibrations on musculoskeletal problems using a Nordic Body Map (NBM) questionnaire. It reveals that the average score of musculoskeletal complaints is 71.6, which defines a high degree of pain. The results of the NBM questionnaire also showed that the vulnerable part of the body which experienced musculoskeletal complaints is the knee. The result of vibration exposure on this body part shows the highest value of 3.437 m/s2. To minimize occupational diseases and accidents, it is necessary to manage a working system that takes into account legal standards, ideal working time, and working shifts in the work area.

Discernibility Measures for Fuzzy β Covering and Their Application

As a combination of fuzzy sets and covering rough sets, fuzzy β covering has attracted much attention in recent years. The fuzzy β neighborhood serves as the basic granulation unit of fuzzy β covering. In this article, a new discernibility measure with respect to the fuzzy β neighborhood is proposed to characterize the distinguishing ability of a fuzzy covering family. To this end, the parameterized fuzzy β neighborhood is introduced to describe the similarity between samples, where the distinguishing ability of a given fuzzy covering family can be evaluated. Some variants of the discernibility measure, such as the joint discernibility measure, conditional discernibility measure, and mutual discernibility measure, are then presented to reflect the change of distinguishing ability caused by different fuzzy covering families. These measures have similar properties as the Shannon entropy. Finally, to deal with knowledge reduction with fuzzy β covering, we formalize a new type of decision table, that is, fuzzy β covering decision tables. The data reduction of fuzzy covering decision tables is addressed from the viewpoint of maintaining the distinguishing ability of a fuzzy covering family, and a forward attribute reduction algorithm is designed to reduce redundant fuzzy coverings. Extensive experiments show that the proposed method can effectively evaluate the uncertainty of different types of datasets and exhibit better performance in attribute reduction compared with some existing algorithms.

Implementing Feedback Granule Size Control in a Continuous Dry Granulation Line Using Controlled Impeller Speed of the Granulation Unit, Compaction Force and Gap Width

PurposeIn continuous manufacturing of pharmaceuticals, dry granulation is of interest because of its large throughput capacity and energy efficiency. In order to manufacture solid oral dosage forms continuously, valid control strategies for critical quality attributes should be established. To this date, there are no published control strategies for granule size distribution in continuous dry granulation.MethodsIn-line laser diffraction was used to determine the size of granules in a continuous roll compaction/dry granulation line (QbCon® dry). Different process parameters were evaluated regarding their influences on granule size. The identified critical process parameters were then incorporated into control strategies. The uncontrolled and the controlled processes were compared based on the resulting granule size. In both processes, a process parameter was changed to induce a shift in median particle size and the controller had to counteract this shift.ResultsIn principle, all process parameters that affect the median particle size could also be used to control the particle size in a dry granulation process. The sieve impeller speed was found to be well suited to control the median particle size as it reacts fast and can be controlled independently of the throughput or material.ConclusionThe median particle size in continuous roll compaction can be controlled by adjusting process parameters depending on real-time granule size measurements. The method has to be validated and explored further to identify critical requirements to the material and environmental conditions.

Towards better understanding of the influence of process parameters in roll compaction/dry granulation on throughput, ribbon microhardness and granule failure load

A key quality attribute for solid oral dosage forms is their hardness and ability to withstand breaking or grinding. If the product is to be manufactured continuously, it can be of interest to monitor the hardness of the material at different stages of manufacturing. Using the controlled process parameters of roll compaction/dry granulation specific compaction force, roll speed and gap width, hardness of the resulting ribbons and granules can be predicted. For the first time, in this study two yield variables (corrected torque of the granulation unit and throughput of material) are used to predict the granules failure load. The increase in granule hardness was monitored in-line when the specific compaction force was increased during the compaction process. This opens the way for in-line control of material hardness, and its use for feedback and feedforward control loops for future continuous manufacturing processes.

Heat Transfer in Fluidized Beds in a Dry Slag Granulation Unit

The world’s leading countries develop dry slag granulation units that are capable of producing solid slag granules and recovering the sensible heat of slag. The main element of such units is a granulation chamber where molten slag is atomized and solidified. In this chamber, up to 30% of the sensible heat of the molten slag is extracted. To recover more heat, the solid granules from the granulation chamber should be fed to fluidized beds. The more there are such beds, the better the granulated slag can be cooled and, therefore, the more heat can be recovered. Foreign publications on dry slag granulation do not provide methods for designing fluidized beds for dry slag granulation units. A method for analyzing the heat transfer in fluidized beds during cooling of slag granules by counter airflow is presented. The method allows determining the heat flow from the slag to the air in fluidized beds and the temperatures of the slag and air exiting the fluidized beds. Recommendations on choosing the airflow velocity, the rational mass of slag in one fluidized bed, the number and dimensions of beds and evaluating air pressure losses in fluidized beds are formulated. It is shown that three fluidized beds in a dry slag granulation unit are sufficient to recover up to 92% of the sensible heat of slag.

CFD modeling of an industrial scale two-fluid nozzle fluidized bed granulator

A 3D computational fluid dynamic modeling of atomization and fluidization of urea was simulated in an external mixing, bottom spray, fluidized bed granulator. The Eulerian–Lagrangian approach was used to predict the mean diameter of melt urea droplets similar to the droplets produced by an industrial scale two-fluid nozzle under hot atomized air. Temperature changes and evaporation of water content from droplets were determined during simulations. Furthermore, three-phase fluidization was simulated in the Eulerian approach whereby the bed expansion of the granulator was predicted. The mean diameter of droplets and bed height were found in good agreement with the empirical correlation and the real bed height, as characterized by a level transmitter instrument in the industrial granulator, respectively. The important features of this study included solving mass, heat and hydraulic equations simultaneously, as well as simulating a real urea fluidized bed granulation unit.

End-Point Prediction of Granule Moisture in a ConsiGma™-25 Segmented Fluid Bed Dryer.

Continuously operated pharmaceutical manufacturing lines often consist of a wet granulation unit operation, followed by a (semi-) continuous dryer. The operating conditions of the dryer are crucial for obtaining a desired final granule moisture. Commercially available dryers lack of a thorough online measurement of granule moisture during the drying process. However, this information could improve the operation of the equipment considerably, yielding a granule moisture close to the desired value (e.g., by drying time and process parameter adjustments in real-time). The paper at hand proposes a process model, which can be parameterized from a very limited number of experiments and then be used as a so-called soft sensor for predicting granule moisture. It utilizes available process measurements for the estimation of the granule moisture. The development of the model as well as parameter identification and validation experiments are provided. The proposed model paves the way for the application of sophisticated observer concepts. Possible future activities on that topic are outlined in the paper.

Predicting Pharmaceutical Particle Size Distributions Using Kernel Mean Embedding.

In the pharmaceutical industry, the transition to continuous manufacturing of solid dosage forms is adopted by more and more companies. For these continuous processes, high-quality process models are needed. In pharmaceutical wet granulation, a unit operation in the ConsiGma-25 continuous powder-to-tablet system (GEA Pharma systems, Collette, Wommelgem, Belgium), the product under study presents itself as a collection of particles that differ in shape and size. The measurement of this collection results in a particle size distribution. However, the theoretical basis to describe the physical phenomena leading to changes in this particle size distribution is lacking. It is essential to understand how the particle size distribution changes as a function of the unit operation’s process settings, as it has a profound effect on the behavior of the fluid bed dryer. Therefore, we suggest a data-driven modeling framework that links the machine settings of the wet granulation unit operation and the output distribution of granules. We do this without making any assumptions on the nature of the distributions under study. A simulation of the granule size distribution could act as a soft sensor when in-line measurements are challenging to perform. The method of this work is a two-step procedure: first, the measured distributions are transformed into a high-dimensional feature space, where the relation between the machine settings and the distributions can be learnt. Second, the inverse transformation is performed, allowing an interpretation of the results in the original measurement space. Further, a comparison is made with previous work, which employs a more mechanistic framework for describing the granules. A reliable prediction of the granule size is vital in the assurance of quality in the production line, and is needed in the assessment of upstream (feeding) and downstream (drying, milling, and tableting) issues. Now that a validated data-driven framework for predicting pharmaceutical particle size distributions is available, it can be applied in settings such as model-based experimental design and, due to its fast computation, there is potential in real-time model predictive control.

Complex designing of granulation units with application of computer and software modeling: case “Vortex granulator”

The article is devoted to the description of the complex method to design granulation unit, which is based on the joint use of the computer modeling results on the simulation models and software modeling based on author’s software products. The description of the software package Granulation Unit© to carrying out the structural and technological calculations for the granulation unit is given. The role of computer and software modeling in the general design algorithm of the granulation unit is shown. The optimization criteria are selected and an algorithm of design optimization for granulation unit is described using the example of the “Vortex Granulator” case. A general method of granulation unit designing “turnkey” with the use of automated design elements is presented. The results of automated calculations form the base to design an industrial granulation unit for the porous ammonium nitrate production. On the example of a specific product of the granulation unit (porous ammonium nitrate), the author’s software product is presented to determine the quality of the porous surface in the granule. This approach in modeling allows to create the automated systems for the optimization calculation of granulation equipment.

Granulation machines with highly turbulized flows: creation of software complex for technological design

The article deals with author’s software products review to calculate devices with highly turbulized flows as a part of granulation units. Principal scheme and model of the granulation unit, algorithm of the granulation technical calculation are represented in the work. The complex automated calculation technique of the granulation units is proposed. The proprietary software for calculation of main stages in the granulation process is observed in the research. Short description and functions of main software products to implement basic algorithm are given: Vortex Flow©, Conical Channel©, Conical Granulator©, Multistage Heat Treatment©, Vortex Tray©. As a result of the optimization calculation, the user of programs will get the following information: optimal construction of the vortex granulator’s workspace, necessary number of stages in the multistage shelf drier for granules’ final drying, number and construction of the vortex tray with heat and mass transfer-separation elements for exhaust gases cleaning. All software products enable to export the received data and to exchange these data between each other. The complex algorithm and software products, proposed in the article, let to carry out optimization calculation of the main technological equipment in the granulation unit at its designing stage without expensive multifactorial experiment. The presented granulation units’ calculation algorithm and software products for its realization enable to carry out equipment changeover if raw material characteristics and the productivity of the unit are changed. The automated calculations results give a base to design industrial granulation unit for porous ammonium nitrate production.

Valorization of anaerobic digestion liquid residue through the production of organic fertilizer by fluidized bed granulation

In this work the feasibility of developing a solid fertilizer by fluidized bed granulation, using digestate (liquid residue from anaerobic digestion) as binder and different minerals as seeds is analysed. Full characterization of the selected mineral particles and the liquid digestate was performed. Particularly, phosphorous and potassium content was assayed before and after granulation. Friability and breakage strength of product granules were tested as well. Also, the process operating conditions (bed temperature, fluidization air temperature and flowrate, digestate temperature and flowrate, etc.) that enable stable operation and the production of completely coated granules were successfully established for lab- and pilot-scale granulation units.

Manufacturing of Pharmaceuticals by Impregnation of an Active Pharmaceutical Ingredient onto a Mesoporous Carrier: Impact of Solvent and Loading

In this study, an active pharmaceutical ingredient (API) was impregnated onto a mesoporous carrier (excipient) in a fluidized bed. Impregnating APIs in porous carriers has the potential to simplify the drug substance development process and leads to the elimination of the blending and granulation unit operations. Impregnation and drying occur simultaneously in fluidized-bed impregnation, and this method precludes several challenges encountered in other impregnation methods. Furthermore, the process ensures a uniform distribution of APIs within the porous carriers. This method also allows for a variety of solvents to be used in the impregnation. Using a batch fluidized-bed dryer, impregnation of acetaminophen (APAP) onto a magnesium/aluminum metasilicate (Neusilin R) was studied. Water and methanol were used as transport solvents to impregnate different loadings (w/w) of APAP, namely, ranging from 24 to 0.1%. Uniformity tests indicated that APAP loadings of all impregnated products are close to their target loadings across carrier size classes. Tests before and after impregnation showed that there were no changes observed in the physical properties of the carrier, such as particle size, compressibility, and flow properties. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis performed on the samples indicated that the low loadings APAP was present in the carrier pores in its amorphous state. At high loadings, we observed that APAP was mainly present in its amorphous state, however, some degree of crystallinity was observed. Lastly, dissolution tests on the impregnated product showed enhanced dissolution rates in acidic media, and comparable dissolution rate in de-ionized (DI) water, compared to the pure drug crystals. Our results show that the method of fluidized-bed impregnation yields a product with high uniformity and overcomes several challenges presented by traditional physical blends.

Liquid‐to‐solid ratio control as an advanced process control solution for continuous twin‐screw wet granulation

Assuring compliance of intermediate and final quality attributes in a continuous pharmaceutical manufacturing campaign is of utmost importance. Application of corrective actions might be required in real‐time. This work exemplifies the steps needed to identify a linear pulse transfer function for the dynamic behavior of the granule liquid‐to‐solid ratio (%w/w) at the end of the granulation unit of a commercial ConsiGmaTM‐25 production line. Near‐infrared spectroscopy was used to monitor the granule composition in‐line. The outcome for both the tracking and regulator problem using either conventional or model predictive control was implemented and evaluated. Dynamic setpoints were correctly followed and an RMSE of 0.25%w/w with respect to the setpoint was obtained when inducing artificial disturbances. Important practical challenges were also tackled. Examples are fouling, computational limitations, and the limited flexibility of the automation software. Applying the proposed advanced process control solution offers an answer to upstream material flow rate deviations. © 2018 American Institute of Chemical EngineersAIChE J, 64: 2500–2514, 2018

Optimization of Heat Recovery for Shell & Tube Exchangers in Sulphur Granulation Unit of South Pars Fifth Refinery by Software, ASPEN B-JAC

Shell and tube heat exchangers are the most important tools in heat transfer process. Optimization efficiency of these tools is always the goal of designers. Now a day there are a lot of efficient methods for selecting the best heat exchanger, such as analytic and numerical methods that everyone has advantages and defects. For example, confront of jamming in calculations by receiving to the local minimums and errors during interruption quantities. Today by entering of simulation and design softwares in industries, the simulation of process tools is so simple. the procedure of studies in this thesis is in these steps: first simulation of sulfur solidification heat exchangers in ASPEN B-JAC software same as operation conditions and then evaluation the effects of changing the design parameters in tube bundle section such as number of passes, arrangement of tubes, number of baffles,…. the sulfur solidification package’ heat exchanger that it’s active fluid is demine water for cooling of package will be optimized till the rate of exchanged heat increases to 15 percent and pressure drop will not affect the operation conditions. The most important note in the correction of tube bundle is that the heat exchanger should be out of service and stopping of production, on the other hand changing in shell of heat exchanger needs to change the piping system and redesign of supports that will spend a lot of time for shut down of plant, so it is out of order for this thesis and optimization of tube bundle will be done.

Blend uniformity evaluation during continuous mixing in a twin screw granulator by in-line NIR using a moving F-test

This study focuses on the twin screw granulator of a continuous from-powder-to-tablet production line. Whereas powder dosing into the granulation unit is possible from a container of preblended material, a truly continuous process uses several feeders (each one dosing an individual ingredient) and relies on a continuous blending step prior to granulation.The aim of the current study was to investigate the in-line blending capacity of this twin screw granulator, equipped with conveying elements only. The feasibility of in-line NIR (SentroPAT, Sentronic GmbH, Dresden, Germany) spectroscopy for evaluating the blend uniformity of powders after the granulator was tested.Anhydrous theophylline was used as a tracer molecule and was blended with lactose monohydrate. Theophylline and lactose were both fed from a different feeder into the twin screw granulator barrel. Both homogeneous mixtures and mixing experiments with induced errors were investigated. The in-line spectroscopic analyses showed that the twin screw granulator is a useful tool for in-line blending in different conditions.The blend homogeneity was evaluated by means of a novel statistical method being the moving F-test method in which the variance between two blocks of collected NIR spectra is evaluated. The α- and β-error of the moving F-test are controlled by using the appropriate block size of spectra. The moving F-test method showed to be an appropriate calibration and maintenance free method for blend homogeneity evaluation during continuous mixing.

Experimental study of rotating dry slag granulation unit: Operating regimes, particle size analysis and scale up

Blast furnace slag is a high-value by-product of the iron and steel industry. It leaves the plant at a very high temperature and possesses a large quantity of high-grade energy. One of the promising methods to extract this energy is dry slag granulation. In this study, the effectiveness of dry slag granulation was studied using a mixture of rosin and paraffin wax as an analogue for blast furnace slag. The effects of various parameters such as rotational speed of the disc, diameter of the disc and flow rate of the molten liquid have been studied. Different ranges of operating conditions in terms of non-dimensional numbers for fiber formation and particle formation were determined. This helps us determine the operating conditions under which particle formation is ensured. The study shows that with an increase in the rotational speed or disc diameter the average particle diameter decreases whereas with an increase in the flow rate the average particle diameter increases. The design of a granulation unit for a commercial plant utilizing the data from lab scale experiments is discussed.

Improved tabletability after a polymorphic transition of delta-mannitol during twin screw granulation

In most formulations processed via continuous twin screw granulation microcrystalline cellulose (MCC) and/or lactose are used as excipients, but mannitol is also a preferred excipient for wet granulation and tableting due to its non-hygroscopicity and inertness. Therefore, the aim of the current study was to investigate the influence of process parameters on critical quality attributes of granules (moisture content, solid state, morphology, size distribution, specific surface area, friability, flowability and hygroscopicity) and tablets (tensile strength and friability) after twin screw granulation of δ-mannitol. The δ-polymorph was selected since a moisture-induced transformation to β-mannitol was observed during batch wet granulation, which exhibited a unique morphology with a large surface area and improved tabletability. A full factorial experimental design was performed, varying screw speed (400–900rpm), granulation temperature (25–40°C), number of kneading elements (6 or 12) and liquid-to-solid (L/S) ratio, on the granulation unit of a ConsiGma™-25 line (a continuous powder-to-tablet manufacturing system). After tray drying the granules were milled and tableted. The results showed that the polymorphic transition from δ- to β-mannitol also occurred during twin screw granulation, although the residence time and L/S ratios were much lower in continuous twin screw granulation compared to batch processing. However, the polymorphic transition was not complete in all experiments and depended on the L/S ratio, screw speed and number of kneading elements. Nevertheless all granules exhibited the unique morphology linked to the polymorphic transition and had a superior tabletability compared to granules produced with β-mannitol as starting material. This was attributed to enhanced plastic deformation of the granules manufactured using δ-mannitol as starting material. In addition, it was concluded that mannitol was granulated via a different mechanism than other, less-soluble, excipients (e.g. lactose, microcrystalline cellulose) due to its high solubility and dissolution rate as the influence of process parameters on the mannitol granule characteristics was different.

Control of ammonia and urea emissions from urea manufacturing facilities of Petrochemical Industries Company (PIC), Kuwait

ABSTRACTPetrochemical Industries Company (PIC) in Kuwait has mitigated the pollution problem of ammonia and urea dust by replacing the melting and prilling units of finished-product urea prills with an environmentally friendly granulation process. PIC has financed a research project conducted by the Coastal and Air Pollution Program’s research staff at the Kuwait Institute for Scientific Research to assess the impact of pollution control strategies implemented to maintain a healthy productive environment in and around the manufacturing premises. The project was completed in three phases: the first phase included the pollution monitoring of the melting and prilling units in full operation, the second phase covered the complete shutdown period where production was halted completely and granulation units were installed, and the last phase encompassed the current modified status with granulation units in full operation. There was substantial decrease in ammonia emissions, about 72%, and a 52.7% decrease in urea emissions with the present upgrading of old melting and prilling units to a state-of-the-art technology “granulation process” for a final finished product. The other pollutants, sulfur dioxide (SO2), nitrogen oxides (NOx), and volatile organic compounds (VOCs), have not shown any significant change, as the present modification has not affected the sources of these pollutants.Implications: Petrochemical Industries Company (PIC) in Kuwait has ammonia urea industries, and there were complaints about ammonia and urea dust pollution. PIC has resolved this problem by replacing “melting and prilling unit” of final product urea prills by more environmentally friendly “granulation unit.” Environmental Pollution and Climate Program has been assigned the duty of assessing the outcome of this change and how that influenced ammonia and urea dust emissions from the urea manufacturing plant.

Scale-up of detergent granules in a high shear mixer

Wet granulation is a process where primary powder particles are made to adhere to form multi-particle entities called granules and this is achieved by using a binder. A simple scale-up of a granulation unit is rather difficult. This becomes even more difficult in a practical situation as the manufacturers make compromises in their scale-up rules on geometries due to cost reasons. Earlier work reported in literature on scale-up emphasized geometrical similarity and proposed various dimensionless numbers for scale-up. Recent work in this area describes granulation process as a multi-scale operation. The final product quality is determined by both macro-scale operation (like rotor speed in a high shear granulator) and micro-scale operation (like particle formation and interaction). Few researchers also talk about an intermediate approach between the macro and micro scales. In this approach, the key transformations such as binder distribution, nucleation, growth, consolidation and breakage were selected based on their relevance to the desired product attributes. The desired product attributes reported in an intermediate approach are chemical homogeneity, granule size, size distribution and granule density etc. There is little published literature on the scale-up of batch granulators in spite of their wide and varied use in the chemical process industries. The aim of this paper is to study the scale-up of detergent powders using a reactive binder processed via wet granulation in a high shear mixer. Three widely used scale-up rules viz. constant Swept Volume, constant Tip Speed and constant Froude Number were tested to identify the right parameters to be scaled for improvements at industrial scale. Bulk properties of the granulation product and mechanical properties of single granules from a desired size range were monitored to decide on the parameters to be scaled. From the bulk properties evaluated, Froude Number emerged as the right approach for scale-up for the system under investigation. However, mechanical properties of single granules did not fit the scaling rules. The strength and yield pressure of individual granules processed at large scale were higher compared to that at a small scale process. Known models of Heckel, and Kawakita and Ludde were used to fit the bulk compression data to estimate single granule properties; which show similar trends as observed in a single granule compression. The Heckel parameter (1/K), and Kawakita and Ludde parameter (1/b) which represents mechanical strength were estimated to be higher for large scale process compared to that for small scale process. In other words, achieving similar particle size distribution does not guarantee similar mechanical properties of individual granules. Hence similarity in single granule properties as well as bulk properties may be a right approach for the scale-up of wet granulation process.

Effect of process parameters and agglomeration mechanisms on NPK compound fertiliser

The granulation characteristics of a calcium carbonate–industrial sulphuric acid-based NPK compound fertiliser have been investigated in a bench scale drum granulation unit. It was found that the granulation of the fertiliser was correlated with both the calcium carbonate's properties and the system's operating parameters, especially the industrial sulphuric acid content and viscosity which were found to govern the granulation process. The surface structure and characteristics of the NPK granules were analysed by scanning electron microscope (SEM) and X-ray diffraction (XRD). The results showed that calcium sulphate formed the coalescence kernel with its high porosity and strength generated by a chemical reaction in the granulation process. Meanwhile, urea sulphate, as a liquid binder, improved the solution–solid phase ratios and binder viscosity.