Rotary Dryer Research Articles

A Study for Estimating the Overall Heat Transfer Coefficient in a Pilot-Scale Indirect Rotary Dryer

An experimental study and dimensional analysis of the effective heat transfer coefficient in a continuous-indirect rotatube dryer using forest biomass as the granular material isare developed in the present work. The study employed a factorial design 33 to investigate the effects of feed flow frequency (20–35–50 (Hz)), drum rotational velocity (6–8–10 (rpm)), and saturated vapor pressure (4–5–6 (bar)) on the heat transfer coefficient. During steady state conditions, the moisture content profiles and inlet and outlet temperatures were measured within the experimental region, and parameters, such as the effective heat transfer coefficient, solid retention change, and moisture content ratio were studied. The results showed that heat transfer was optimized with high solid feeding rates, low pressure, and low rotation, with solid feeding being the predominant factor. The moisture content profiles revealed a change in the hydrodynamic behavior, with the center point of the experimental region being the least optimal. The dimensional analysis yielded a Nu number as a function of Pe, Fr, and the feeding dimensionless number. A new dimensionless energy efficiency number improved the coefficient correlation from 85.88 (%) to 94.46 (%), indicating the developed model potential to predict dimensionless variables and scale continuous-indirect rotatube dryers.

Performance Evaluation of Rotary Dryer and Granulator in NPK Steam Granulation Plant Production Department of IIB PT Petrokimia Gresik

PT. Petrokimia Gresik, a subsidiary of Indonesian fertilizer company PT. Indonesian Fertilizer, has three main plants: Production I, II, and III. Production IIB consists of production units Phonska IV, NPK Granulation II, III, and IV and ZK. Granulated NPK II Fertilizer is a processing unit that meets quality standards. The process involves feeding raw materials, preparing slurries, granulating, drying, screening, cooling, and screening. Supporting materials include powder coating, oil coating, and pigment. The granulation stage is crucial, where raw materials are agglomerated. The NPK Granulation Department of IIB uses various equipment, including a rotary dryer with a thermal efficiency of 79.997%. The total mass balance for the granulator, dryer, cooler, screen, and coater in NPK Granulation II for 15-15-15 fertilizer formula is 1058,096 tons/day.

Implementation of fuzzy logic control algorithm for temperature control in robusta rotary dryer coffee bean dryer

Background: Indonesia is one of the coffee producers ranked third in the world in the supply of coffee beans. To maintain competitiveness international market, it is necessary to maintain and improve the quality of coffee beans.Objective: One crucial aspect of maintaining the quality of coffee beans is maintaining the moisture content of green coffee beans. One of the water content settings is using the drying method. While traditional drying methods often experience weather and long-time constraints.Results: This study designed an innovative coffee bean dryer based on fuzzy logic to overcome the problem. This system uses temperature control with Mamdani's fuzzy logic control interference algorithm, input and delta errors, and output percentage valve opening. This method achieved a moisture content following SNI standards of 12% and a 0.00015% / s drying rate for each coffee bean mass increased by 1kg. This method is also more efficient and stable in maintaining the temperature at a value of 50°C.Methods: The drying equipment also estimates the drying time by considering variations in the mass of coffee beans. This dryer can provide an effective solution to maintain optimal coffee bean quality.Conclusion: The second semi-wash method of drying coffee beans using a fuzzy logic-based coffee bean drier has proven successful for drying coffee beans to a moisture content of 12% in a period of 90 min to 195.65 min with a drying capacity of 1 kilogram to 10kg at 50°C.•The coffee beans utilized in the studies are robusta coffee beans from plantations on Mount Kawi's slopes in East Java, Indonesia.•The trial sample was 1 kilogram of green coffee beans removed from the horn skin.•According to SNI standards, the drying performed is the second in the postharvest semi-wash procedure to achieve a moisture content of 12%.

Energy analysis and quality characteristics of flaxseed oil by using an infrared rotary dryer

An infrared (IR) rotary dryer was designed and fabricated to sterilize flaxseeds under different experimental treatments. The investigations were conducted under varying IR intensities (882, 964, 1050, and 1140 W/m2) and exposure times (6, 9, 12, and 15 min). Data analysis showed the minimum amount of specific energy consumed at 882 W/m2 and 6 min for the studied varieties Sakha 3 and Sakha 6. The highest thermal efficiency belonged to the highest radiation intensity and the lowest exposure time, with values of 77.26 % and 86.17 % for Sakha 3 and Sakha 6, respectively. Different IR intensities caused an increase in oil yield (OY), acid value (AV), and peroxide value (PV). For example, 1050 W/m2 for 15 min showed the highest OY for Sakha 3 (37.37 %), whereas 964 and 1050 W/m2 for 12 min reported the highest activity for Sakha 6 (43.20 and 43.43 %, respectively); 1140 W/m2 was the intensity that recorded the highest content of AV (range of 2.67–3.93 mg KOH/g for Sakha 3 and 3.19–4.22 mg KOH/g for Sakha 6) and PV (range of 4.05–6.91 meq. O2/kg for Sakha 3 and 5.21–5.92 meq. O2/kg for Sakha 6). Moreover, increasing IR intensity caused an increase in total phenolic content. The maximum amount was obtained at 1140 W/m2 for 12 min (153.27 and 154.59 mg GAE/100 g sample for Sakha 3 and 6, respectively) without significant changes at 1050 W/m2 and 12 min. For radical scavenging activity, 1050 W/m2 at 9, 12, and 15 min represented the highest activity for Sakha 3 (range of 30.27%–32.64 %) and Sakha 6 (range of 36.58%–37.37 %). Thus, IR pretreatment at 1050 W/m2 and duration between 12 and 15 min is recommended for Sakha 3 and 6. After the oil extraction and storage period (4 weeks), PV increased in all the investigated oil samples. In general, the heat-treated seeds’ oil will stay stable and maintain quality as long as the seeds are stored before the oil is extracted.

Efficiency Investigation of Coffee Production Waste Drying by Filtration Method

This article presents the results of determining the technologically feasible parameters of filtration drying of coffee production waste based on experimental data on the kinetics of material drying and the hydrodynamics of thermal agent filtration. The lowest total energy costs were observed with the following process parameters: the material layer height of 120 mm, the thermal agent temperature of 90 °C, the velocity through the stationary layer of 1.76 m/s, and the specific energy consumption of 5857 kJ per 1 kg of water. Based on the determined technologically feasible process parameters, an evaluation of the filtration drying method for coffee production waste was performed at an industrial installation. According to the calculation, using the filtration method, 1164 kW h of energy was required to dry about 1000 kg of coffee production waste. A total energy of about 1.65 kW h/kg was required to remove 1 kg of moisture from the material in an industrial filtration drying installation. The results were compared with a drying material with similar initial parameters. It was calculated that to dry 1000 kg of coffee production waste in a rotary dryer, it is necessary to spend about 1625 kW h, and the total energy consumption for removing 1 kg moisture from the studied material is approximately 2.37 kW h/kg. Thus, for a similar output of about 1000 kg/h, filtration drying can reduce energy consumption by about 465 kW·h and reduce the required drying time by more than 20 times. The overall economic effect of using the filtration drying method in industry is expected to be higher, given the significant heat losses to the environment for a rotary dryer due to its large size, long drying time, design features, and the need for energy-intensive auxiliary equipment. After calculating the energy consumption per 1 kg of dry material, it is necessary to spend 12 950 kJ/kg of dry matter, about 41.5 % less than the higher calorific value for experimental samples of briquetted solid fuel made from this material. This result makes it economically feasible to further dry coffee production waste to produce alternative solid fuels.

Grain movement between the cylinders of a semi-automatic rotary dryer during heating

Grain movement between the cylinders of a semi-automatic rotary dryer during heating

Implementation of Rotary Dryer for Cassava Drying as a Raw Material for Mocaf Flour Production

Modified cassava flour (mocaf) is one of the innovative cassava processed products with high market value and promising business prospects as a substitute for imported wheat flour. The women's farming group (KWT) Ngudi Sari, located in the village of Tanjungsari, Gunungkidul, has processed cassava into mocaf flour and various cassava-based products, including cassava chips, tiwul, gatot, mocaf sticks, and various cookies. During the production process of mocaf flour, one of the common challenges faced is the drying of cassava chips, which has traditionally relied on sunlight and home-based drying methods. With the increasing demand for mocaf flour, large-scale drying of cassava chips becomes necessary. To address this challenge, a technology of rotary dryer is implemented to KWT Ngudi Sari to enhance the efficiency and effectiveness of the cassava raw material drying process. This outreach project aims to empower KWT Ngudi Sari and boost the production capacity of the resulting mocaf flour. The application of this appropriate technology is expected to improve the quality of cassava as a raw material for mocaf production and enhance its energy efficiency, thus contributing to the economic development of KWT Ngudi Sari. Throughout the project, mentoring, monitoring, and evaluation are also conducted to measure the progress in knowledge and skills of the partners involved.

Experimental and numerical study of an alternative technique for fruit processing: Rotary drum with inert bed for acerola pulp dehydration

Acerola is renowned as a potent natural source of vitamin C. However, its high perishability presents challenges for harnessing its health benefits. In this study, we explored an alternative method, the Rotary Dryer with Inert Bed (RDIB), to transform acerola pulp into a powdered form. Through both experimental and numerical investigations, we quantified how various operational variables affect RDIB's performance in acerola pulp dehydration. In numerical simulations using the Discrete Element Method (DEM), we analyzed the number and forces of particle collisions. We combined DEM results into a single response using a desirability function, pinpointing the optimal configuration: a drum with three continuous flights, each 25 mm long. Subsequently, experimental tests with this optimal setup considered temperature (T), inert fraction (FI), and maltodextrin concentration (M) effects on drying yield and bioactive compound levels. Multi-response optimization aimed to maximize both yield and bioactive compounds, yielding the optimal conditions: M = 6.25%, FI = 46.19%, and T = 77.2 °C. Thus, the results of this study show that RDIB efficiently dehydrates acerola pulp and has promising potential for industrial applications, facilitating the production of high-quality fruit powder.

Thermal Study of the Utilization of Rice Husks Using the Forced Convection Method as Energy for a Rotating Cylinder Dryer

Small farmers in rural areas use the sun as their main energy source to dry post-harvest products. Due to limited knowledge and technology, farmers depend on the sun through direct drying. Direct use of the sun for the drying process has disadvantages in uncertain weather such as cloudy or rainy. This results in the drying process not being optimal or even stopping. This research aims to use rice husks as energy to replace direct sun drying to produce optimal temperatures so that drying time is shorter and the quality of the dried food is hygienic. Rice husk as an energy source is applied through a rotating cylinder dryer. This dryer is tailored to farmers' needs, namely easy to operate at an affordable price. This energy can be utilized sustainably because it is abundant through a forced convection system and energy conversion using a heat exchanger. The design of the compact rotary dryer includes an integrated drying chamber in one unit with the combustion furnace and a heat exchanger. The drying chamber includes a rotating cylinder and a fixed cylinder. The test results show that hot air from burning rice husks flows through the heat exchange pipes by conduction from the furnace to the walls of the drying chamber and by forced convection through an exhaust fan installed in the drying chamber. The average environmental temperature of 29.55-29.69oC has increased when using one exhaust fan to 64.46oC and two exhaust fans to 60.11oC. This drying temperature can produce shorter drying times, so it can be applied to post-harvest product drying, which is energy-efficient and sustainable for small farmers. Based on research results, rotating cylinder dryers powered by rice husks are very suitable for small farmers to replace direct sun drying.

Performance evaluation of a flighted rotary dryer for lateritic ore in concurrent configuration

The lateritic ore drying in the Cuban nickel producing industry is realized within flighted rotary dryers. In this investigation, performance indicators in regards to transfer of momentum, heat and mass were evaluated. The dryers operate in a concurrent configuration with combustion gas, at a productivity between 40 t h−1 and 50 t h−1. The distribution function of the residence time (RTD) was best fitted to a model of a multi-branch tanks-in-series system, theoretical residence time was 51 ± 2 min and experimental mean residence time 61 min, at a rate of 45 t h−1 and hydraulic efficiency 1.23, due to the presence of dead-zoon. Mass and energy balance was made following a “black box” model, as results, the specific fuel consumption was 27.25 ± 0.25 kg fuel t−1 of wet ore, specific energy consumption 79.66 ± 0.95 kg fuel t−1 of H2O evaporated, energy efficiency 97.28 ± 0.01 %, thermal efficiency 66.88 ± 0.71 % and drying efficiency 98.77 ± 0.12 %. Mathematical modelling was made using a system of differential equations, the rate of drying in falling rate period was estimated by Arrhenius equation, then, temperature profile and ore moisture content along the dryer was simulated. The model provided a successful predictive performance; for an inlet gas temperature between 850 °C and 900 °C, the ore moisture was reduced form 33.0 % (wet basis) to a range depending on the dryer productivity, from 3.0 % to 7.1 %. Designing a computerized system that implements these algorithms can benefit on efficiency and productivity of the production plant.

Thermodynamic and sensitivity analyses on drying subprocesses of various evaporative dryers: A comparative study

Drying is an energy intensive process, which takes a big portion of global energy consumption. The innovation of energy-saving drying techniques are crucial for the sustainable development. To achieve energy saving of evaporative drying, exergy destructions and losses in the dryers should be located. In this study, the drying process is divided into three subprocesses, i.e., heat transfer, moisture evaporation and diffusion, and drying exhaust emission. Thermodynamic models of dryers are developed, and performance of evaporative dryers, including rotary, solar, spouted bed, etc. Are analyzed and compared. The exergy consumption rate, i.e., the exergy consumption rate to dehydrate 1 kg water, is defined and used to evaluate the energy utilization of dryers. The exergy consumption rate of dryers ranges from 330 kJ (kg H2O)−1 to 10,490 kJ (kg H2O)−1, which is mainly related to the energy consumption rate and energy grade. The irreversibility of the three subprocesses of dryers are compared, e.g., for the rotary dryer with hot air at 300 °C as heat source, the exergy loss and destruction of the subprocesses are 415.7, 451.3, and 293.4 kJ (kg H2O) −1, respectively. The results of this study can provide guidance to enhance the energy utilization efficiency of evaporation dryers.

An adaptive optimization method toward batch-wise variable set point of outlet moisture content for the tobacco drying process

The tobacco drying process in the cigarette production has an important effect on the final product quality. Therefore, the intelligent control methods have been widely investigated to ensure the stability of tobacco’s outlet moisture content. The existing work mostly uses a relatively fixed set point of the outlet moisture content for different tobacco batches, which can lead to unforeseen product quality after several processes following the drying process and inaccessible amount of dehydration for the rotary dryer. Some tobacco moisture prediction methods have been studied recently while the relationship with the intelligent control methods remain largely unexplored. To deal with these issues, a novel method is proposed in this paper to identify the optimal set point of the drying outlet moisture content for each tobacco batch. An encoder-decoder model is first developed to forecast the post-drying moisture trajectory. Then, an adaptive filter with specially designed mechanisms and a confidence interval of the dehydration level are constructed to obtain the design constraints. Based on all above, a constrained optimization problem is formulated and solved by the genetic algorithm. Extensive experiments on 895 tobacco batches from a large cigarette factory are carried out, which involves both algorithmic evaluation and field test. It turns out that the proposed method achieves the superior performance and leads to an improvement of the product quality in real production.

PROSES PENGERINGAN NPK BERDASARKAN EVALUASI ROTARY DRYER DAN KADAR AIR NPK DI PT. PETROKIMIA GRESIK

Drying is an important process in the production of NPK fertilizers. The average NPK water content in August 2021 – January 2022 was 1.64%, still exceeding a good NPK water content of < 1.5%. The high NPK moisture content resulted that review are needed in drying process through rotary dryer evaluation and observation by creating multiple linear regression math. The average thermal efficiency is calculated based on the actual data, which is 73%, do not decrease significantly and still close to the value of the design data of 90%. The mathematical equation obtained is Y1 = 114.9292 + 0.000338X1 + 0.0439062X2 -1.711792X3 -0.3749378X4 with a regression coefficient of 0.8657472. Factors that affect the NPK fertilizer water content are the air temperature of dryer, the flow rate of incoming NPK water mass, the flow rate of NPK mass and the flow rate of air dryer mass.

Analysis of intensification of zeolite drying on a vibrating conveyor dryer with infrared emitters

The object of the research is the drying process of zeolite. The work is dedicated to analyzing an effective method for intensifying the drying process of zeolite while preserving its structural integrity. For the given task, it was necessary to choose a promising drying method with minimized heat loss and preservation of the quality indicators of zeolite. Zeolite has a wide range of applications, including soil improvement, mineral fertilizer for plant growth, dietary supplement for animal feed, air, and water purification. The crucial process for obtaining high-quality natural zeolite is the drying process. In its natural state, zeolite contains moisture, and an excess of it can deteriorate its consumer properties. Therefore, considering the best and most efficient method of zeolite drying is a promising task today. There is no available data on drying zeolite using radiation methods in the literature. Typically, this material is dried in rotary dryers. However, this drying method often results in a significant percentage of zeolite being crushed into dust. Many industries require a granular structure for zeolite. With radiation drying, this drawback is absent or the percentage of crushed zeolite into dust is minimal. The main methods of drying zeolite have been examined, revealing a fact that indicates an incorrect approach to the drying process. Factors influencing the deterioration of zeolite's quality during drying have been analyzed. These factors have several drawbacks that affect the final product, namely: crushing zeolite into powder, over-drying, which affects its quality and poses a general scientific problem. The drawbacks of drying zeolite using the main methods have been identified. The authors have developed a dryer design that minimizes the deterioration of the mentioned qualitative characteristics of zeolite, addressing an important scientific and technical challenge of creating an efficient and environmentally friendly method of zeolite drying using infrared radiation energy and the development of appropriate equipment. The proposed dryer has suggested applications in various fields.

Hazard and Operability Study of Rotary Drum Dryer in Hazardous Waste Management Industry

Abstract: The HAZOP study is distinguishing the Hazards related to process, equipment and working methods and evaluate the probability take control measures to protect the workers and company asset. in this project analysand details hazards and Operation failure modes to affect the production and legal requirements. Such as The Atmospheric gas monitoring equipment needs to be installed around the machines to detected LEL and TVOC compounds to eliminate environment concern and Worker’s health. the overall purpose of the study to identify the hazards and risks, then remove/minimize the hazards by providing recommendation control measures. And Create danger free zone workplace. In this paper I have used quantitative and quantitative methods used to find the Operation failures and Possible Hazards. I have analyzed and exam pined the work/process locations is has more hazards to work more difficult even though in good housekeeping and preventive measure.

Numerical Simulation of Drying Process within a Novel Rotary Drying Machine for Palm Oil Sludge

This study investigated how to model a centre-offset annular rotary drum using OpenFOAM and the meshing software GMSH. The diameter of the outer cylinder is 600 mm, diameter of the inner cylinder 200 mm, the centre-offset mm, and rotation rate rpm. When the centre-offset is zero, the quality of mesh is preserved as the drum rotates. Introduction of the offset causes the mesh to be deformed to the point of being unusable as the drum is rotated. The reason was found to be the fixed nodes adjacent to the walls of the outer and inner cylinder. These nodes only respect the motion of the wall they are adjacent to. To circumvent this, we separated the inner volume of the rotary drum to allow the implementation of an OpenFOAM dynamic mesh handling scheme called arbitrary mesh interface (AMI). Implementing AMI allows the quality of the mesh to be kept even when the inner cylinder is rotating under nonzero-offset conditions. This is because AMI permits the sliding of non-conforming meshes next to each other. This preserves the quality of the mesh and secures a reliable and reproducible dynamic mesh motion for the implementation of the drying process in the future.

Rancang bangun mesin pengering buah pinang tipe rotari dengan sumber panas api kompor berbahan bahar oli bekas

This study aims to describe the working system and test the performance of the machine, to find out an overview of reducing the moisture content of betel nut dried with a rotary type betel nut dryer machine with a heat source from a used oil-fueled stove fire. The methods used in the study consist of the design stage and the performance test stage. The design stage was to carry out the construction design process, material selection, and fabrication process. While the performance test stage aims to determine the ability of the machine to carry out the betel nut drying process. The results of the design of the rotary type betel nut dryer machine consist of a heating system and a drive system. The heating system uses heat from the used oil-fueled stove and the drive system uses an electric motor connected to the reducer gearbox to rotate the cylinder of the drying chamber. The maximum air temperature generated during the 7-hour performance test process was 108oC with an air flow speed of 3,8 m/s. The results of the design of the drying machine are able to reduce fruit mass by 5.5 kg with a drying rate of 0.785 kg / hour on wet betel nut. The reduction in the moisture content of dried betel nut is directly proportional to the reduction in mass. During the 7-hour drying process, the moisture content of the betel nut is reduced by 55% with a reduction rate of 7.85% / hour

Capacity Planning of New Product in PT Perkebunan Nusantara VIII (Oolong Tea)

In early 2021 PTPN VIII began producing a new product based on consumer demand, namely oolong tea, within an estimated contract worth IDR 6.000.000.000 of 150 tons. Thus, the firm should be prepared related to the garden and the factory to produce the oolong tea. This research uses a quantitative descriptive method by analyzing the capacity of the garden to provide the raw material for oolong tea; in the process of oolong tea production, the garden can provide 2.5 tons per day, exceeding the calculation of 1.9 tons. However, the machine used for the production process is inadequate. The machine’s capacity is only available to produce 106.78 tons per year, which is below consumer demand. It requires the firm to add three rotary dryer machines. Adding three machines meant oolong tea production reached 150 tons only in 13 hours and 25 minutes. Adding these machines also requires the firm to invest as much as IDR 540,000,000; by this investment value of the machine, the payback period will return in 4,4 years with the machine durability more than 25 years.

Mathematical Modelling of Rotary Drum Dryers for Alfalfa Drying Process Control

Rotary drum dryers operating in co-current mode are commonly used for drying food and feed in leaf form, reducing the damage caused by the high air temperatures typical of these dryers, as well as providing advantages including reduced drying times and increased energy efficiency. However, drying control to ensure a desirable product exit moisture content is strongly based on empirical practices, which are usually jealously guarded by producers and users, grounded in simplified mathematical modelling. To overcome these uncertainties, in this work, a more complete mathematical modelling approach, based on the solution of ordinary differential equations (ODEs), is developed. The ODEs describe the drying process in the drum dryer, where the air is continuously cooled and humidified as the product dries. The mathematical model developed was experimentally verified in a drum dryer by drying alfalfa, and the maximum relative error was found to be only 2.4%. Finally, a comparison between the complete model proposed here and a simplified model was conducted, using both for drying control to keep the product exit moisture content constant (i.e., at 0.111). The results indicated that the simplified model provided values of air inlet temperatures erroneously higher, up to +8.2%, with a consequent higher energy consumption, lower dried alfalfa quality, and a greater risk of fire, given that the product exit temperature was dangerously increased.

Development and Preliminary Testing of Rotary Dryer for Plantain Flour Processing Plant

Plantain postharvest losses are significant in Nigeria and efforts are focused on processing the crop into storable products to ensure its availability throughout the year. To obtain the desired flour quality and quantity, plantain must be dried for an hour at a temperature not exceeding 70 °C and then discharged without human intervention. There have been significant obstacles in plantain processing. Regular turning of plantain pulps during drying, and intimate contact between them and the hot-drying air should be ensured to retain plantain nutritional and esteem values in the flour produced. In this study, a rotary dryer was developed. The machine is capable of drying plantain within the aforementioned hour and temperature range and is suitable for use in a plantain flour processing plant. A preliminary test was conducted to assess the fabricated prototype’s functional performance and plantain particulates were able to move through the dryer. Upon varying the air-inlet aperture of the dryer from 0 to 125,680 mm2, the drying air velocity increased from 0 to 4.4 m/s. The airinlet aperture was proportional to air velocity/volume, particulate deflection within the dryer, particulate loss from the dryer and the time taken by the heater to reach the desired drying temperature. It became evident that drying air velocity/volume, deflection and particulate loss can all be influenced regardless of the blower’s speed, potentially affecting the dryer’s capacity and efficiency.