Drum Granulation Research Articles

Гранулирование пылевых отходов кремниевого производства для возврата в технологический процесс

The purpose of the work is to propose a granulation technology for dust waste of metallurgical silicon production for its recycling in the process of ore-thermal reduction of silica. The technology includes the stages of magnetic separation, granulation and drying. Experimental works on iron oxide separation from cyclone dust were performed using a magnetic analyzer of the AMR type (Ukraine). Granulation was carried out using a drum granulator R-020 (Russia). The chemical composition was analyzed with the help of an optical emission spectrometer Varian 730-ES (USA). It has been determined that up to 37% of iron oxide is separated by the method of magnetic separation of silicon production cyclone dust. In the laboratory pelletization in a drum granulator the granules of 10-70 mm in size with the porosity of 40-45% were obtained. The carried out experiments have showed that there is a possibility in principle to use production wastes in the production technology of silicon of metallurgical grades as a pelletized additive to the main (lump) charge. Based on the results obtained, a line for granulating dust waste was proposed.

Production of solid biofuel granules from drum granulation of bio-waste with silicate-based binders

Herein compost was selected as a model bio-waste substrate to make solid biofuel granules using wet drum granulation and a sodium silicate binder. Using a laboratory-scale drum granulator (300 g/batch), spherical compost granules within the targeted size range (3.35–14 mm) could be produced with a good compressive strength in good to excellent yields. The effects of compost moisture content, process parameters (drum speed, granulation time) and binder parameters (binder concentration, binder to compost ratio) on the properties of the resulting granules (size distribution, bulk density, compressive strength, water resistance, gross calorific value, ash content) were investigated. The optimal conditions for producing granules as a solid biofuel with competitive properties when compared with woody biomass fuels were achieved by applying a drum rotational speed of 32–37 rpm, granulation time of 15 min, sodium silicate solution 1–3 wt% and binder to solid ratio 0.77–0.90.

Study of Devulcanised Crumb Rubber-Peat Bio-Based Composite for Environmental Applications

A proper recycling and secondary reuse of end-of-life car tires (ELTs) remain an important issue for many regions. Devulcanised crumb rubber as a product of ELT recycling could be used for very different applications, including site remediation by spilled oil products. In current paper a development of new bio-based composite material containing devulcanised crumb rubber and cenospheres is suggested. Designed bio-based composite can be used as a oil spill adsorbent, material for civil engineering, and as a raw material for further modification by introduction of ferromagnetic components. Homogenised peat with peat content 14.0 ± 1.5 wt%, particle size 0.01 – 0.5 mm used as a natural bio-based binder. Devulcanised crumb rubber particle size 1.0 – 4.0 mm was used as a porous substrate. Designed compositions contained 5, 10, 15, 20 wt% (before drying) of devulcanised crumb rubber. Cenospheres have duplex function for designed composite: lightweight additive that makes final product floatable, and at the same time minimises shrinkage of dried product. It was found that devulcanised crumb rubber reduces density of final composite and adding open porosity. Developed bio-based composites could be manufactured in granules by drum granulation technique for further environmental applications. Formability and apparent density of bio-based composite are studied.

Granulation of fly ash and biochar with organic lake sediments – A way to sustainable utilization of waste from bioenergy production

The main waste generated during the thermochemical processes of biomass burning used for bioenergy production in cogeneration plants are ash and biochar which can be used as fertilizers in forestry and agriculture. However, several difficulties are attributed to possibilities of practical exploitation of ash and biochar due to the transporting, handling and mode of application. Granulation of energy generation waste has been shown in some circumstances as a cost-effective and environmentally friendly method. Production of granules (pellets) from wood ash and biochar leads to improved recycling and logistics of waste as well as helps to control and avoid undesirable environmental effects such as leaching of nutrient excess.The aim of this study was to prepare granules from wood fly ash and biochar mixed with organic-rich freshwater lake sediments (sapropel) used as a natural binder and a source of organic matter for enrichment of derived granules to be applicable as a soil improver. Characterization of raw materials and derived granules included range of physical and chemical analysis. Applied granulation technology involved homogenization of components following by extrusion and drum granulation, and the process was developed for prospective production of soil improvers. It was estimated that the most optimal mass ratio of raw materials applicable for the process of granulation is 67:100 (fly ash to sapropel) and 30:100 (biochar to sapropel) resulting in production of granules 3–8 mm in diameter. Among the characteristic parameters of granules apparent density, bulk density, compressive strength, total element content and element content by fractions was assessed.

Effect of chemical and physical properties of Dried Distillers Grains with solubles (DDGS) on Tribolium castaneum (Herbst) development

Dried Distillers Grains with Solubles (DDGS) has been used as a grain-based supplement in animal feed. The focus of this study was to investigate the effects of chemical and physical characteristics that may affect DDGS susceptibility to Tribolium castaneum (Herbst) infestation. Multiple regression-based models were built to determine if the diet’s chemical and physical characteristics affect T. castaneum development. Based on the regression models, diet particle size was the most influential factor in larval development. Larval weight increased more rapidly on T. castaneum normal laboratory diet, 90% flour/10% brewer’s yeast (F/Y), followed by ground DDGS, compared to raw DDGS with different particle sizes. To determine the effect of diet particle size on larval development, experiments were conducted to increase particle size by pelletizing F/Y using a rotary drum granulation apparatus. T. castaneum larval stage lasted significantly longer on F/Y granules with a particle size of 1.4 mm or larger. Although the chemical properties of DDGS (protein, fat, fiber and ash content) were not significant predictors of T. castaneum larval development, larval developmental time and weight gain on ground DDGS was significantly slower than on F/Y, highlighting the potential importance of nutritional factors not accounted for in our analysis. Our results conclude that storing DDGS as raw ingredient and in the granule or pellet form with large particle size may help limit T. castaneum infestations. Although granulation or pelletization may not be economically feasible for small manufacturing plants, larger producers may benefit from the reduced risk of insect contamination associated with secondary feeders such as T. castaneum.

A comparison of drum granulation of biochars

ABSTRACT Drum granulation can be used to form biochar granules that could reduce dust hazards during biochar application to soils. An investigation of the effect of operational parameters using three biochar feedstock was conducted to identify the effect of biochar feedstock on granule properties. Cornstalk, birchbark and miscanthus biochar powders were successfully granulated and found to have varying granulation mechanisms, attributed primarily to differences in hydrophobic behaviour. Cornstalk granulated similarly to hydrophilic powders while birchbark had delayed granule nuclei formation resulting in larger nuclei. Miscanthus did not penetrate into the biochar powder and granulated through layering. All three operational parameters affected granule size. An increase in liquid volume and rotational speed increased the granule size of all three biochars. Binder concentration had a negative effect on granule growth due to viscous forces that decreased granule deformation. Granule strength was high for all three types of biochar granules and was affected by rotational speed of the drum and the liquid binder concentration. Increased binder concentration increased granule strength by promoting consolidation. Rotational speed of the drum had varying effects on granule strength due to differences in the granulation mechanisms of the biochars. The results demonstrate that multiple biochar feedstock can be granulated using wet drum granulation, but granulation parameters must be adjusted to produce granules with specified characteristics.

Resource-saving materials based on hydrophobic low water demand binder

This research have shown that the developed composition and method for preparation of granulated organic–mineral admixture S–3SSA allow production in drum granulator of cement materials modifier with de-sired properties using proposed mixing procedure for the admixture ingre-dients which include, mass. %: superplasticizer S–3 – 10; soap stock – 20; salt of inorganic acid – 30 and ash – 40. On the basis of laboratory studies, a ratio of the components included in the molding compound for pressed bricks with improved physical and technical properties was defined. Opti-mal composition of the molding compound should contain the following, mass.%: binder - 10; clay - 5; sand - 82; water - 3. A technological proce-dure for production of pressed brick based on gypsum binders of low water demand (GLWDB) was developed and technological production parame-ters were defined: moulding compound moisture content - 6%; raw materi-al strength – 0.4 MPa; specific pressure - about 15 MPa, curing conditions - natural. Basic physical and technical properties of pressed brick based on GVNV–50S were identified and studied. Strength kinetics, MPa: 1 day – 6.8; 3 days - 12.3; 28 days – 27; density-1950 kg / m3; softening coefficient equal.

МОДЕЛИРОВАНИЕ ГРАНУЛИРОВАНИЯ ПОРОШКОВ ТИТАНОМАГНЕТИТОВОГО КОНЦЕНТРАТА И ИХ ВОССТАНОВЛЕНИЕ ПРИРОДНЫМ ГАЗОМ

Моделировано формирование гранул из порошков титаномагнетитового концентрата, содержащего до Fe- 54%, TiO2 - 7%, V- 1% и Mn – 0.8% масc.доли, с флюсовыми добавками 25% масc.доли соды. C использованием термодинамических расчетов определены условия восстановления гранул природным газом в фильтрующем слое трубчатой печи при 875-925 °С с получением железного порошка и титановой фракции. Зависимость степени металлизации (μ,%) офлюсованных (25% Na2CO3) гранул титаномагнетитового концентрата от температуры восстановления природным газом при продолжительности восстановления t=30 мин, скорости подачи природного газа ν = 0.1 л/мин и при объеме природного газа пошедшего на восстановление V=0.6 м3/кг аппроксимирована полиномом:
 μ = 14.933.10-6T3 – 0.043T2 + 41.222T – 13042

Drum granulation of single super phosphate fertilizer: Effect of process variables and optimization

In this work we investigated the effects of the drum rotation speed, liquid-phase ratio, granulation time, and drum hold-up on the single super-phosphate granulation performance in a rotary drum. Regression techniques were used to quantify the effects of those variables on the granulation efficiency and product properties. Equations to predict these responses as functions of the studied variables were proposed. Sequential Quadratic Programming (SQP) algorithm was used for the optimization study. The results showed that the levels of the process variables that led to the highest efficiency were not the same for the highest granule hardness. From the results of this study it is possible to identify conditions that improve the granulation efficiency and the physical properties of the final product.

The Effect of Wetting on The Course of The Drum Granulation

Abstract This paper presents the results of experimental drum granulation of silica flour with the use of wetting liquids with different values of surface tension. Additionally, different liquid jet breakup and different residual moisture of the bed were applied in the tests. The process was conducted periodically in two stages: wetting and proper granulation, during which no liquid was supplied to the bed. The condition of the granulated material after the period of wetting (particle size distribution and moisture of separate fractions) and a change in the particle size distribution during the further conduct of the process (granulation kinetics) were determined.

Wettability in water/iron ore powder systems: To the universality of the Cassie model

During iron ores granulation process minimization of the volume of water is of vital economic importance due to the associated energy cost of evaporation in the second sintering step. The optimisation of water addition demands understanding of capillarity properties of iron ore mixtures to ensure at the same time good mechanical strength of iron ore granules and just needed minimum of water in the granulation drum. Thus, in the current work wettability and capillarity properties of 7 iron ores, 7 additives and 7 mixtures of those components were studied. It was found that particles with size below 0.1mm have a big influence on the contact angle and percentage of infiltrated water of mixtures. Particularly, the content of hematite Ore 1 had a significant effect on the contact angle. The use of calcine and dolomite additives affects slightly the magnitude of the water surface tension, but modifies the wettability of iron ores. The adaptation of the Cassie model for mixtures of iron ores of >2-phases gave an excellent estimation of the contact angle for mixtures with size particles below 0.1mm. A good estimation for mixtures with particles larger than 0.1mm was also obtained.

An investigation on process of seeded granulation in a continuous drum granulator using DEM

Numerical simulation of wet granulation in a continuous granulator is carried out using Discrete Element Method (DEM) to discover the possibility of formation of seeded granules in a continuous process with the aim of reducing number of experimental trials and means of process control. Simple and scooped drum granulators are utilized to attain homogenous seeded granules in which the effects of drum rotational speed, particles surface energy, and particles size ratio are investigated. To reduce the simulation time a scale-up scheme is designed in which a dimensionless number (Cohesion number) is defined based on the work of cohesion and gravitational potential energy of the particles. Also a mathematical/numerical method along with a MATLAB code is developed by which the percentage of surface coverage of each granule is predicted precisely. The results show that use of continuous granulator for seeded granulation is promising provided that a high level of shear is considered in the granulator design, i.e. using baffles inside drum granulators is essential for producing seeded granules. It is observed that the optimum surface energy for seeded granulation in scooped granulator (used in this study) with rotational speed of 50 rpm is 3J/m2, which is close to the value predicted by the concept of Cohesion number. It is also shown that increasing the seed/fine size ratio enhances the seeded granulation both quantitatively (60% increase in seeds surface coverage) and qualitatively (more homogeneous granules).

The effect of filling of the drum on physical properties of granulated multicomponent fertilizer

One of the operations in particulate processing which has an ancient history and a widespread use is granulation. Granulated compost fertilizer was granulated using the drum granulation method under different level of drum filling. Filling of the drum ranged from 5 to 10% (v/v). The effect of filling of the drum on some physical properties granulated compost fertilizer including: useful granules, granules size, crush strength, mass of the granules, bulk density, angle of friction and angle of repose are investigated in the present study. Result indicated that with the increasing of drum filling the percentage of useful granules, crush strength, bulk density, angle of friction and angle of repose increase from 64.97% to 78.82%, 34.32 N to 36.69 N, 745.585 kg/m 3 to 762.729 kg/m 3 , 25.56o to 27.93o and 11.38o to 12.52o, respectively. Also the average size of granules decreases from 10.28 mm to 9.45 mm.

The effect of process variables on drum granulation behavior and granules of wet distillers grains with solubles

A laboratory scale batch drum granulation process was used to manufacture granules of DDGS by adding condensed distillers solubles (CDS) as a binder to wet distillers grains (WDG), coproducts from corn dry-grind ethanol process, under varying formulation and process conditions. A full factorial experimental design was used to test all combinations of factor levels, which included the amount of CDS binder (30%, 35%, and 40% (w/w)), CDS binder solids content (22% and 38%, wet basis), screen size opening (3.175 and 6.35mm), and residence time (1, 2.5, 5, and 10min). Measured response variables included granule size (geometric mean diameter), granule yield (1.68–3.35mm), bulk density, true density, and porosity. Results show that as the amount of binder added increased from 30% to 40% the granule size significantly increased from 2.08 to 4.45mm, respectively. Increasing the binder solids content resulted in granules with greater bulk density. Granules produced from the low solids CDS had lower porosity as a result of intraparticle voids in them. Screen sizing influenced nucleation and produced significant differences in the final granule size distribution. The greatest growth was observed for granules prepared with 40% amount of binder and low solids content CDS. Compression testing of wet granule compacts corresponded to observed growth behavior; wet pellets made from higher solids CDS had greater resistance to deformation and enhanced plasticity while the opposite was observed for the low solids CDS. The best yields of granules between 1.68 and 3.35mm were achieved at ∼80% using 35% amount of binder with the high solids content CDS, the small screen size opening and residence times between 2.5 and 10min.

Particle Motion Simulation and Parameter Optimization Design in Drum Granulation

Drum granulators are widely used in powder granulation industry, and particles’ sphericity is one of the important indexes of drum granulation quality. To improve the particle sphericity, it is necessary to study the influence of particle size and shape on particles’ motion of both attitude and trajectory in the drum. This paper presents a mixed method of the discrete element simulation, orthogonal design experiment and mathematical statistics to investigate the influencing factors of particle orientation. The study found that there is a certain effect of particle shape, size and the speed of the drum on the particle orientation. According to the range analysis, it can be concluded that the effect of the three factors on the particle orientation is in the order of particle shape > particle size > the speed of the drum. Optimum combination was observed to be particle shape, size, and the speed of the drum are homogeneous ellipsoidal particles, 3 mm and 40 rpm, respectively. The study will facilitate to optimize the granulation process parameters.

Experimental investigations towards understanding important parameters in wet drum granulation of corn stover biomass

Biofeedstocks such as corn coproducts or biomass such as corn stover are typically densified in a dry process using pellet mills to enhance transportability and use as livestock feed. Our work presents data of an experimental study using a non-traditional means, wet granulation with a lab-scale rotary drum granulator to determine key parameters that affect granule properties and yield of desirable sized granules. Granules were manufactured from corn stover and two liquid coproducts from corn bioprocessing, corn steep liquor (CSL) and corn molasses (CM) by varying corn stover particle size, corn stover:coproduct blend ratio and granulation residence time. The results showed that different formulation and processing parameters affected corn stover granulation. Granulation with an initial particle size of 0.88–0.96mm (from screen size 6.4mm), low liquid level (1:4) with CM, and short residence time (0.5min) could be used to produce desirable sized granules (1.78 to 7.87mm) for ruminant livestock feed with yields of over 98%. The effect of initial particle size of corn stover particles on density of granular products was significant. Corn stover particle size also positively influenced the granule size and negatively influenced yield of desirable granules. While increased coproduct (CM and CSL) levels in the blend increased the granule particle size and density, yield of desirable granules was reduced.

Study of orientation and morphology of elliptical particles in drum granulation by dynamic simulation

Sphericity is an important indicator of particle flow properties in rotary granulation. Here, a dynamic simulation approach is proposed to study the formation of particle sphericity during agglomeration by investigating both the orbit and attitude of non-spherical particles in a rotary drum. First, geometric criteria are presented to substitute a dual-sphere particle model for the commonly encountered ellipsoidal particle model assuming the long radius of the dual-sphere particle is equal to that of the ellipsoidal particle. Next, a discrete element method is applied to calculate the positions and orientations of dual-sphere particles during granulation. The relationship between shape and attitude in the dual-sphere model is then analyzed by comparing the obtained orientation angle–oblateness curves. A conclusion can be drawn that the particle orientation angle decreases with increasing particle oblateness within a certain range.

An investigation of drum granulation of biochar powder

Biochar is a fine powder that is difficult to handle and would be blown away if applied to soils without modifications. Wet drum granulation of biochar using binder solutions of hydroxypropyl methylcellulose was investigated to create a form that would be easier to handle and apply effectively to the soil. The biochar granules were free flowing and approximately spherical with a significant yield between a size range of 1 to 4mm. The binder concentration, total binder solution volume and drum rotational speed all affected the yield of granules within this size range. The drum rotational speed and binder concentration affected the granule strength; biochar granules were resistant to attrition and showed a crushing strength of 0.15 to 0.50MPa. The results demonstrated that biochar can be granulated using wet drum granulation. Further research is required to further refine the granulation parameters to produce granules with comparable characteristics to fertilizers to ensure that the granules could be effectively applied to soils using existing infrastructure and techniques.

Granular ferric hydroxide adsorbent for phosphate removal: demonstration preparation and field study.

Ferric hydroxide (FHO), which has high phosphate adsorption capacity, was prepared by precipitation at industrial scale and then fabricated via the drum granulation method with cross-linked poly(vinyl alcohol) as the binder. The optimum binder/FHO powder ratio was 0.6 for producing a granular adsorbent with a high phosphate adsorption capacity and stability. The Langmuir maximum adsorption capacities of powder and granular FHOs were 74.07 mg g⁻¹ and 56.18 mg g(-1) at pH 7.0 ± 0.2, respectively, which were higher than those of other reported phosphate adsorbents under neutral or acidic conditions. Phosphate-loaded granular FHO could be regenerated by NaOH solution. Columns containing the granular FHO were used for phosphate removal from ozonated secondary effluents of a municipal wastewater treatment plant at space velocity (SV) of 2 and 5 h⁻¹. During more than 2 months' operation, the average removal percentage of PO(4)(3-) was more than 90% and the turbidity and concentration of CODMn in the effluents were lower than in the influents. In addition, energy dispersive X-ray results suggested that active sites inside the granular FHO were available for phosphate removal. The results demonstrated that granular FHO can be applied as an assist technology for phosphate removal from secondary effluents.

Kinetic laws of the granulation process of powdered materials in drum granulators

Theoretical and experimental studies of the influence of moisture of granules on their formation, deformation, and size distribution in the course of granulation of powdered materials in drum machines were considered. It was noted that the simultaneous proceeding of granule formation and compacting is of wave and damped character. The problem of forced convective transport of the binder in the pores of granules in its compacting was solved.