BIXIN POWDER PRODUCTION IN CONICAL SPOUTED BED UNITS

ABSTRACT

Recent work has demonstrated that the red carotenoid bixin is easily extracted from Bixa orellana seeds by particle attrition and impact rather than by solvent extraction. This technique may require a previous step for drying seeds at a safe temperature to preserve pigment quality. A spouted bed (SB) with a draft tube is the most appropriate equipment to process both seed drying and bixin extraction at low operational costs. Operational parameters of the SB unit are optimized as a function of the powder production rate. The maximum air inlet temperature for drying the seeds is also specified. A high performance liquid chromatography method has been developed for the semi-quantitative determination of bixin content in the powder produced. Results show that this SB unit can be more competitive than ball mill equipment.     

Production of annatto concentrates in spouted beds

Annatto is composed of a natural reddish-yellow pigment, which is commonly used in the food, cosmetic and pharmaceutical industries. This pigment is easily extracted from Bixa orellana seeds by particle impact and attrition rather than by solvent extraction. Seeds must be dried at a safe temperature to preserve the pigment quality. Experiments show that the annatto powder produced in a non-conventional spouted bed has a high pigment content and is thus suitable for commercial use. A comparative analysis of the bixin extraction in different systems demonstrates that this spouted bed unit can be competitive for commercial applications. Hydrodynamic and drying parameters were studied to improve the powder production rate in this unit.     

胭脂树种子制备红木素的研究

研究了从胭脂树种子制备红木素的方法，通过正交实验确定了最佳工艺条件。丙酮作为溶剂时提取效果最好，其最佳工艺条件物料比（胭脂树种子和丙酮的质量体积比（g／mL）为1：4，温度为50℃，时间为2h。本方法简便、提取率高，适用于工业化生产。     

Corn,Rice, and Wheat Seed Drying by Two-Stage Concept

Corn, rice, and wheat seeds with an initial moisture content (IMC) of 20–25% wb were dried to moisture content below 18% wb at 40–80°C in a fluidized bed dryer (FBD) and spouted bed dryer (SBD) and the seeds with IMC 18% wb were dried to below 14% wb at air temperatures 18–30°C and relative humidity 60–70% by an in-store dryer (ISD). As a result, it appears that a two-stage drying concept is feasible in drying high-moisture-content seeds due to the high germination rate of dried seeds. Nonetheless, the drying temperature must be carefully selected. A drying temperature of 40°C was clearly safe for all samples, whereas more than 90% of wheat seeds still germinated after drying at 60°C in FBD. Furthermore, drying seeds with IMC 18% wb by ISD was safe under specified drying conditions.     

DESIGN AND APPLICATION OF A DEHUMIDIFIER DRYER FOR DRYING PINE CONES AND POLLEN CATKINS

A critical issue for the plantation forest industry is the preservation and control of genetic material in order to facilitate the fertilisation process. This is best achieved by drying at low temperature and low humidity prior to extraction of seeds and pollen. For example, freshly picked green cones of Pinus radiata are best dried at 25°C, 20% relative humidity to avoid thermal damage and to prevent mould formation. Similar conditions are required for drying pollen catkins. These conditions can be met efficiently and reliably by the use of a dehumidifier dryer. This paper describes the design of such a drying system, including a review of the dehumidifier and the kiln design parameters necessary to achieve the required drying conditions. Performance data and commercial operating experience are also presented and analysed. The system is effective and reliable, and has increased both the speed of drying and the quality of the product.     

DESIGN AND APPLICATION OF A DEHUMIDIFIER DRYER FOR DRYING PINE CONES AND POLLEN CATKINS

ABSTRACT

A critical issue for the plantation forest industry is the preservation and control of genetic material in order to facilitate the fertilisation process. This is best achieved by drying at low temperature and low humidity prior to extraction of seeds and pollen. For example, freshly picked green cones of Pinus radiata are best dried at 25°C, 20% relative humidity to avoid thermal damage and to prevent mould formation. Similar conditions are required for drying pollen catkins. These conditions can be met efficiently and reliably by the use of a dehumidifier dryer. This paper describes the design of such a drying system, including a review of the dehumidifier and the kiln design parameters necessary to achieve the required drying conditions. Performance data and commercial operating experience are also presented and analysed. The system is effective and reliable, and has increased both the speed of drying and the quality of the product.     

DRYING OF OILSEEDS

Drying of oilseeds is a post harvest operation required for safe storage of harvested seeds. Oilseeds have gained importance in India over the last few years. Fluidized bed (FB) drying and Spouted Bed (SB) drying of oilseeds were studied as potential dryers for these seeds. Experimental pilot fluidized bed dryers were developed and a 2 TPH capacity (mustard seed) FB dryer plant was designed and installed in the lab. Experimental units and a pilot spouted bed dryer were also developed. The dryer units and the plant have been extensively tested and satisfactory drying performance has been achieved. Drying data and drying characteristics have been generated for different oilseeds such as mustard, sunflower, soybean and groundnut etc. The drying rates in different regimes of drying characterized by constant rate and falling rate periods have been evaluated. The salient results of the work are briefly outlined.     

Drying of seeds through oscillating infrared heating

Oscillating infrared (IR) drying of onion, white mustard, sweet pepper, and wheat seeds as well as the effect of this drying method on the seeds’ stimulation have been studied. It was found that oscillating IR drying was highly advantageous for onion seeds which possess the lowest germination degree and germination energy. The influence of initial moisture content of the onion seeds, the duration of the oscillating IR drying, and the processing temperature on the stimulation effect have been established. The most favorable stimulation temperature was determined. It was shown that this stimulation effect holds unchanged for at least eight months. A mathematical model for drying kinetics based on the solution of the mass conductivity equation was proposed and the method of the process engineering calculation has been developed and validated for onion and mustard seeds. The necessary experimental data on mass conductivity and concentration equilibrium for onions and mustard seeds have been obtained.     

Performance of a recirculating dryer equipped with a desiccant wheel

This article reports the incorporation of a rotary desiccant wheel unit into an air recirculated convective dryer and testing it by drying corn kernels. Experiments were conducted with and without the desiccant wheel at air temperatures of 50, 60, and 70°C and flow rates of 1, 1.4, and 1.8 kg/min. The effect of drying temperature, air flow rate, and desiccant wheel on drying time, drying rate, energy consumption, and specific moisture extraction rate were investigated. Statistical analysis of data showed that air drying temperature and air flow rate had significant effects on drying time and drying rate and the effect of desiccant wheel on drying time was significant. Results indicated that a desiccant wheel is an economical and useful system to utilize in dryers because it decreases drying time while increasing the drying rate and has a positive influence on energy consumption.     

Drying of Pharmaceuticals: The Applicability of Spouted Beds

This study evaluates the performance of conventional spouted beds (CSB) with inert bodies in the drying of pharmaceutical pastes, based on the dry product quality. The powder obtained by drying annatto extracts shows properties comparable to one of the commercial products, indicating that the spouting is competitive with other industrial and lab-scale processes. The contents of bixin and caffeine in annatto and guarana dry powders demonstrated a strong dependence on the inlet air temperature. Also, the properties of indomethacin-containing microcapsules dried in CSB and spray dryers revealed that spouting is a promising technique to obtain pharmaceutical forms with unique drug release qualities.     

STUDY ON HEAT TRANSFER CHARACTERISTICS AND DRYING EXPERIMENT OF SINGLE SEED

Studies in the seeds drying field are presently aimed at macro heat and mass transfer of the whole seeds heap, but for drying of life materials, such as the seeds, the control of their internal temperature is essential. Therefore, the study of the heat transfer process of the internal single seed is pressed. This paper experimentally studied the measuring method of the thermal conductivity for the single broad bean seed, and then obtained an interrelated curve between the thermal conductivity and water contents for single seed. During the drying, the internal temperature could be derived from the surface temperature of the seeds and it contributed to deciding the safe drying temperature of the seeds. Then we derived the thermal conductivity of the seed coat and the cotyledon by testing and calculating the temperature fields of the inner cross section in the seed, which quantitatively indicated the difference of the thermal resistance between the seed coat and the cotyledon. In order to conquer the thermal resistance, appropriate drying conditions could increase the drying speed on the condition that the activity of seeds was maintained. In this paper, the Chinese cabbage seeds are selected to experimentally validate this method through the two-pass infrared radiation vibrated dryer and produces some satisfactory results. These results will contribute to the improvement of the drying quality and the efficiency of the life materials, such as the seeds.     

Drying of Pharmaceuticals: The Applicability of Spouted Beds

ABSTRACT

This study evaluates the performance of conventional spouted beds (CSB) with inert bodies in the drying of pharmaceutical pastes, based on the dry product quality. The powder obtained by drying annatto extracts shows properties comparable to one of the commercial products, indicating that the spouting is competitive with other industrial and lab-scale processes. The contents of bixin and caffeine in annatto and guarana dry powders demonstrated a strong dependence on the inlet air temperature. Also, the properties of indomethacin-containing microcapsules dried in CSB and spray dryers revealed that spouting is a promising technique to obtain pharmaceutical forms with unique drug release qualities.     

Vibrofluidized Bed Drying of Adipic Acid

Adipic acid is a white crystalline solid and is the most industrially important of all aliphatic dicarboxylic acids. Drying is the principal unit operation after its crystallization. The acid has a tendency to agglomerate when moistened, due to its high cohesiveness. The fluidization regime does not occur and the particles cannot be adequately treated in a conventional fluidized bed. This article deals with the drying of adipic acid in a vibrofluidized bed. The equipment used in the drying tests was specially designed and constructed to maintain the fluidized regime of fine particles of moistened adipic acid. The drying curves presented the constant and the falling rate periods, yielding final moisture contents that depend mainly on the drying temperature. The quality of the dried acid was also verified by the crystals' granulometric analysis, which showed breakage of crystals for drying at higher air temperatures. Results showed to be satisfactory for drying adipic acid with moisture content up to 5.1% w.b. in the vibrofluidized bed, keeping a high degree of bed homogeneity and quality of the fluidized state.     

THE THERMO-IMAGE EXPERIMENTAL STUDY FOR THE OPTIMIZATION OF SEEDS DRYING

Using the method of combining the two subjects of engineering thermophysics and physiology, this paper carried out the thermo-image experiments of drying Chinese cabbage seeds at both dynamic and static states in the infrared radiation vibrofluidized dryer that was made by us. Meanwhile the seed physiology experiments were also conducted. The results show that the critical drying temperature of seeds is the function of their drying time and moisture content. It is higher when the initial moisture is lower, or the drying time is shorter. This provided the theoretical basis for the optimization of heat and mass transfer of seeds drying.     

STUDY OF SOLID-LIQUID EXTRACTIONS IN A BATCH EQUIPMENT

A batch pilot-scale apparatus is described for the study of processes for obtaining phyto-extracts using solvents. The distinctive feature of the equipment is that it provides the efficiency of a multi-stage counter-current extraction, yet uses only a single batch extractor (as opposed to a battery of extractors). This is achieved by using an auxiliary tank in which intermediate extracts are saved and recirculated in a pre-established order. Careful design of the mechanisms for the circulation of liquid from such tanks has resulted in an apparatus that is compact and has simple, flexible operation. A prototype of this apparatus was constructed for the study of the direct extraction of oil from sunflower seeds using hexane A simple model that describes the operation of the equipment is presented and applied to our experimental work with oilseeds.     

EXPERIMENTAL RESEARCH ON DRYING CHARACTERISTICS OF LITCHI

The changes of inner temperature and drying characteristics of rind, membrane, flesh and stone of Litchi were investigated under constant relative humidity of drying medium at different temperatures at atmospheric and decompression conditions. Results show that the membrane resists moisture from moving the flesh or stone to rind. Decompression drying is helpful to the moisture evaporation of the fruit; when the moisture content lowers to a certain critical point, the drying rate is higher than that of atmospheric drying. Drying curves are very different from those of seeds drying or particle drying. In the drying process, temperature of Litchi whole fruit rises quickly at the beginning to a maximum region, then falls to a minimum before rising again slowly. All the phenomena are due to the composite structure of Litchi.     

Saffron Drying with a Heat Pump–Assisted Hybrid Photovoltaic–Thermal Solar Dryer

Saffron is the most expensive spice and Iran is the largest producer of this crop in the world. Saffron quality is profoundly affected by the drying method. Recent research has shown that hybrid photovoltaic–thermal solar power systems are more efficient in comparison with individual photovoltaic and thermal systems. In addition, heat pump dryers are highly energy efficient. Furthermore, they are suitable for heat-sensitive crops such as saffron. Therefore, in the present study, the performance of a hybrid photovoltaic–thermal solar dryer equipped with a heat pump system was considered for saffron drying, in order to obtain a high-quality product and reduce fossil fuel consumption. The effect of air mass flow rate at three levels (0.008, 0.012, and 0.016 kg/s), drying air temperature at three levels (40, 50, and 60°C), and two different dryer modes (with and without the heat pump unit) on the operating parameters of the dryer was investigated. The results of the investigation showed that total drying time and energy consumption decreased as air flow rate and drying air temperature increased. Applying a heat pump with the dryer led to a reduction in the drying time and energy consumption and an increase in electrical efficiency of the solar collector. The average total energy consumption was reduced by 33% when the dryer was equipped with a heat pump. Maximum values for electrical and thermal efficiency of the solar collector were found to be 10.8 and 28%, respectively. A maximum dryer efficiency of 72% and maximum specific moisture extraction rate (SMER) of 1.16 were obtained at an air flow rate of 0.016 kg/s and air temperature of 60°C when using the heat pump.     

Enzyme-aidedvs. two-stage processing of canola: Technology,product quality and cost evaluation

The investigation focussed on the use of carbohydrase enzymes to enhance oil extraction during pressing in a laboratory expeller. Enzyme-treated seeds at 6% moisture were pressed in the expeller set at full-press conditions. Control seeds were pressed at wider choke openings but at the same barrel pressures as enzyme-treated samples. Time of pressing and temperature and pressure inside the expeller barrel were used to calculate throughput and energy requirements per unit weight of processed material. Treatment with enzymes improved throughput of the expeller, increased oil flow rate and oil recovery. Material throughput was increased by 30–50%, depending on canola variety. The recovery of the oil was increased from 72% of the seed oil for control samples, to 90–93% for enzyme-treated samples. The average residual oil content in presscakes from enzyme-treated seeds was 7.4%. The oil quality was inferior to cold-pressed control but was much better than has been reported for solvent-extracted oil.     

Optimization of the process of drying of corn seeds with the use of microwaves

Abstract

The heating and drying of various types of food using microwave improve the economy of time and energy. The physiological quality variation of the seeds submitted to microwave drying is known to some extent. In this context, some authors have reported excellent performance using this technique, on germination rates, after drying. The commercial use of microwave drying in seeds is irrelevant, which motivates more extensive research on the benefits and challenges of this technique that can increase its insertion in the post-harvest handling steps of agricultural products. Corn is a product of high worldwide relevance. Therefore, the use of microwaves in its drying process has excellent potential to arrive at significant savings in its production. Thus, this study is aimed to evaluate the effects on the physiological quality of the seeds submitted to different drying conditions, using the microwave radiation. To that end, corn seeds, with a water content of 20% on wet basis (w.b.), were dried at 40, 50, and 60?°C, at power ratings of 0, 0.6, and 1.2?W/g; in the vacuum condition. Drying occurred continuously, with intermittent power, until the seeds reached the 12% wet basis; in this condition, the seeds could be stored with secure. Germination tests performed shortly after drying showed that the temperature of 40?°C at a power of 0.6?W/g had a reduction in drying time of approximately 5?h when compared to conventional drying (40?°C and 0.0?W/g). The evaluation of the physiological quality of the seeds showed no significant difference in the germination, vigor, and longevity indices of the treated seeds.     

Vibrofluidized Bed Drying of Adipic Acid

ABSTRACT

Adipic acid is a white crystalline solid and is the most industrially important of all aliphatic dicarboxylic acids. Drying is the principal unit operation after its crystallization. The acid has a tendency to agglomerate when moistened, due to its high cohesiveness. The fluidization regime does not occur and the particles cannot be adequately treated in a conventional fluidized bed. This article deals with the drying of adipic acid in a vibrofluidized bed. The equipment used in the drying tests was specially designed and constructed to maintain the fluidized regime of fine particles of moistened adipic acid. The drying curves presented the constant and the falling rate periods, yielding final moisture contents that depend mainly on the drying temperature. The quality of the dried acid was also verified by the crystals' granulometric analysis, which showed breakage of crystals for drying at higher air temperatures. Results showed to be satisfactory for drying adipic acid with moisture content up to 5.1% w.b. in the vibrofluidized bed, keeping a high degree of bed homogeneity and quality of the fluidized state.