Optimizing the single screw extruder die head to produce organic-based fertilizer pellet

Abstract: Pellet production is an effective method for efficient use; reduce transportation costs and improvement of economic efficiency for organic wastes such as vermicompost and municipal solid waste compost. Physical and rheological properties of the material are essential for the design of pellet machine accessories. In this study the rheological parameters of yield stress (σ0), shear stress (τ0) and velocity factors (α and β) were determined by using a capillary rheometer. The number of holes of single screw extruder die was also determined according to achieved results. The experiments on the materials at 45% moisture content resulted the values, σ0 = 0.09 MPa, τ0 = 0.009 MPa, α = 3.1 MPa sm-1and β = 0.11 MPa sm-1for paste compost and σ0= 0.506 MPa, τ0 = 0.02498 MPa, α = 0.0357 MPa sm-1and β = 0.00145 MPa sm-1for vermicompost. The best results were achieved for single screw extruder with 10 holes for paste compost and with 7 holes for vermicompost. Keywords: rheology, capillary rheometer, compost, vermicompost, pellet, extruder, biomass

Effect of moisture content and particle size on energy consumption for dairy cattle manure pellets

Physical and mechanical properties of pellets are needed to make pellet form in storage of raw materials and energy consumption.  Dairy cattle manure, sieved by a two-level size of 30 and 50, were used to make pellets by a hydraulic press with mold diameter of 6 mm, in five moisture levels of 15%, 17.5%, 20%, 22.5% and 25% and two pressure levels of 100 and 150 MPa.  The results of the tests were analyzed using Excel and MATLAB softwares.  Results showed that the compression energy as well as friction energy of size 30 increased with the increasing moisture content from 15% to 20%, and decreased with the increasing moisture content from 20% to 25%, and both are under pressure levels of 100 and 150 MPa.  The compression energy and friction energy of the size 50 decreased with the increasing moisture content for both pressure levels of 100 and 150 MPa.  The energy consumption of compression was found to be greater at the pressure of 150 MPa than that of 100 MPa.  The greater amount of energy consumption was used for compression.  The maximum amount of friction energy was 16.7%, while the minimum was 11.23% for both pressure levels of 100 and 150 MPa. Keywords: energy consumption, compression energy, dairy cattle manure, friction energy, pellet, pressure  

Design, construction and evaluation of shear vane device for biomass yield stress determination

Abstarct Agglomerate followed by pelleting is one of the efficient methods to decrease transport costs and increase economic efficiency of biomass material. Understanding the rheological properties of biomass is necessary for pelleting process optimization as well as the design of devices with enough energy and pressure to determine the effect of different variables on the density and durability of pellets. The rheological properties of extruded material is depended to properties and moisture content of the raw material, used for extrusion. Therefore, in this study a shear vane was developed to determine the rheological properties of biomass materials. The output rotation of the electromotor was measured by a rotary encoder and the forces to the vane blades, inserted by the material, were measured by a bending loadcell. The experiments were done at moisture content levels of 35, 40 and 45%, and rotational speed of the shear vane container at three levels of 0.1, 0.2 and 0.3 rpm. The results showed that the higher maximum torque was achieved at 35% moisture content and rotational speed of 0.1 rpm. The lowest maximum torque was found at 35% moisture content and rotational speed of 0.2 rpm. The maximum shear stress and yield stress were obtained at 35% moisture content and rotational speed of 0.1 rpm while the minimum shear stress and yield stress were found at 35% moisture content and rotational speed of 0.2 rpm

Effective moisture diffusivity and mathematical modeling of drying compost pellet

Compost compression processes, such as pelleting, increase bulk density, improve storability, reduce transportation costs and make easier materials handling using existing equipment for handling and storage of grains. It is important to prevent quality deterioration of pellets in long time storage. Therefore, it is necessary to reduce the moisture content of the pellets to less than  or less. In this research the drying kinetics of compost pellets were studied at air temperatures of 50, 60 and 70 , air velocities of 0.5, 1 and 1.5 , particle sizes of 1.18 and 2 mm and pellet diameters of 6 and 8 mm. The maximum effective moisture diffusivity (1.78× ) was obtained at air velocity of , air temperature of 70 , particle size of 1.18 mm and pellet diameter of 8 mm. The activation energy of compost pellets varied from to  under different conditions. The Page model was selected as the most suitable model, based on the statistical analysis

Determining dimensional, gravimetrical and frictional properties of red radish seeds (Raphanus Sativus L.) as a function of moisture content

To design the planting, separating, threshing, sizing and packing machines for agricultural products, physical and mechanical properties of the products should be known. In this paper, some physical properties of red radish seeds were studied. Dimensional parameters, when moisture content equals to 5.65% based on dry bases (d.b), were measured using image processing technique. Effects of moisture content on gravimetrical and frictional properties of the seeds, including mass of single seed, 1000-unit seed, bulk density, true density, porosity, static coefficient of friction on various surfaces, and angle of repose based on pouring, Hele-Shaw, empting and filling methods were studied. Effects of volume of the container (150, 350, 550 and 750 mL) and height of fall on bulk density and porosity of the radish seeds when moisture content equals to 5.65% (d.b) were studied. Also length, width, thickness and mass distributions of radish seeds were modeled using Gamma, Generalized Extreme Value and Weibull distributions. Results showed that length, width and thickness of the seeds ranged from 0.660 to 0.900 mm, 0.524 to 0.763 mm and 0.490 to 0.759 mm, respectively. With increasing volume of the container from 150 to 550 mL, bulk density of the seeds increased; but with increasing volume of the container from 550 to 750 mL, bulk density of the seeds decreased. With increasing volume of the container from 150 to 550 mL, bulk density of the seeds increased; but with increasing volume of the container from 550 to 750 mL, bulk density of the seeds decreased. With increasing moisture content from 5.65 to 21.71% (d.b) , bulk and true density of the seeds decreased from 694.807 to 654.889 kg/m3 and 1141.810 to 1057.795 kg/m3; but with increasing moisture content from 5.65% to 21.71% (d.b) , 1000-unit mass increased from 6.98 to 7.17 g

Optimization compressive strength biomass pellet from compost using Taguchi method

Compression is important to prevent a deterioration in quality pellets for long term storage and the moisture content of the pellets must be reduced to or less. In this research the quality of pellet of compost was studied at air temperatures of 50, 60 and 70, air velocities of 0.5, 1, and 1.5 m/s, particle sizes of 16(1.18mm) and 10(2mm) and pellet diameters of 6 and 8 mm. The Taguchi quality engineering method was used to investigate the effects of parameters on compressive strength of pellet. An orthogonal array, signal-to-noise (S/N) ratio analysis of variance (ANOVA) were employed to analyze the effect of these compressive strength parameters. Thus, the optimal performance for the compressive strength of pellet was obtained at first level of factor A, i.e. the particle size (16 (1.18 mm)), third level of air temperature (70 ).and second level of air velocity (1 m/s). Finalliy, confirmation tests verified that the Taguchi method was successful in compressive strength of pellet

The effect of moisture content, particle size and consolidation stress on flow properties of vermicompost

 Physical properties of granular solids are essential to design appropriate, efficient, and economic bulk solids handling and storage equipment.  Flow of vermicompost is often restricted by caking and bridging, which occurs during transportation and storage.  This problem could be due to a number of factors including storage moisture, temperature, particle size, and consolidation stress.  There is lack of study on the effect of the mention factors simultaneously on flow index, cohesive strength and angle of internal friction of vermicompost.  The aims of this work were to discuss the primary factors affecting flowability of vermicompost as granular solids and powders, as well as using shear testing methodologies for this biomass material.  The experiments were conducted on samples selected from a wormy culture farm, Karaj, Iran, by Jenike’s shear cell technique.  The data was statistically analyzed using the three factors completely randomized design to study the effects of particle size, moisture content and consolidation stress on vermicompost flow properties.  The results showed that a significant difference between the flow index values at different stress levels.  Greater moisture content and smaller particle size caused poor flowability of vermicompost.  Increasing the moisture content and decreasing the particle size from 1.18 to 0.3 mm, the vermicompost reduced its flowability from free flowing at moisture content of 25% (w.b.) to cohesive at moisture content of 35% (w.b.).   Keywords: biomass flowability, flow index, shear test, vermicompost

Poultry litter angle of wall friction

Dependence on chemical fertilizer is continually increasing.  Continual increasing of using chemical fertilizer causes nature pollution (e.g. water contamination).  This has led researchers to aggressively investigate renewable fertilizer resources and biomass to produce organic crops and reduced wastage.  Poultry litter is a bulk solid and biomass feed stocks. The angle of wall friction (AWF) is a critical factor in designing and constructing suitable equipment for pelletizing.  The results of this study showed that the simple effects of the moisture content (M) and surface types (S) as well as interaction of the S × particle size (P) and S × M were significant (

Association of glutathione S-transferase polymorphisms with the severity of mustard lung

Introduction: Glutathione S-transferase (GST) is one of the major detoxifiers in alveoli. Polymorphism in GST genes can influence the ability of individuals to suppress oxidative stress and inflammation. The present study was aimed to explore the hypothesis that the genetic polymorphisms of GST T1, M1 and P1 are associated with the severity of the mustard lung in the sulfur mustard-exposed individuals. Methods: Blood samples were taken from 185 sulfur mustard-exposed and 57 unexposed subjects. According to the stage of the mustard lung, sulfur mustard-exposed patients were categorized in the mild/moderate and severe/very severe groups. A multiplex PCR method was conducted to identify GSTM1 and GSTT1 null genotypes. To determine the polymorphisms of GSTP1 in exon 5 (Ile105Val) and exon 6 (Ala114Val), RFLP-PCR method was performed. Results: The frequency of GSTM1 homozygous deletion was significantly higher in the severe/very severe patients compared with the mild/moderate subjects (66.3% vs. 48%, P = 0.013). The GSTM1 null genotype was associated with the severity of mustard lung (adjusted odds ratio [OR], 2.257; 95% CI, 1.219-4.180). There was no significant association between GSTT1 and GSTP1 polymorphisms with the severity of the mustard lung. Conclusion: The different distribution of GSTM1 null genotype in severe/very severe and mild/moderate groups indicated that the severity of the mustard lung might be associated with the genetic polymorphism(s)