Extraction of Frozen Berry Raw Materials with a Vibration Tray Device

Introduction. Products containing natural extracts are in great demand. However, poor production technologies make them too expensive to satisfy consumer demand. As a result, a variety of intensification methods have been developed to increase the economic efficiency of extraction, e.g. low-frequency mechanical vibrations. However, frozen raw materials have to be processed at low temperatures, which makes the method less efficient. The research objective was to intensify the extraction process from frozen berries in a vibration tray device by increasing the temperature of the system of interacting phases. Study objects and methods. The research involved frozen cranberries and blueberries. They grow everywhere in Western Siberia and are rich vitamins and minerals. The berries were subjected to slow freezing at –18°C, which destroyed the cell structure and increased the processing efficiency. The study was carried out in a lab device with a vibrating tray. All parameters were measured by standard methods. Results and discussion. The extraction device was equipped with a jacket into which a coolant was fed, i.e. water with a temperature of 55°C. A preliminary series of experiments revealed two negative aspects associated with the supply of coolant into the jacket. First, the surface layer started to thaw, which reduced the efficiency of grinding. Second, the processing time increased. A new method was developed to solve these problems: the coolant was supplied at the end of the grinding. The time of the coolant supply depended on the type of raw materials. The processes that occurred within the device depended on two factors: the frequency of vibrations of the tray and the diameter of the holes in the tray. These factors could be adjusted to intensify the process, but they increased the power costs and energy consumption. A series of experiments determined the optimal values of these parameters. A mathematical analysis revealed regression equations, i.e. how the destruction time and power costs affected the main parameters. The established optimal process parameters made it possible to determine the minimal time of the destruction process: for cranberries – 2.5 min, for blueberries – 1.5 min. The minimal power consumption was 17.8 watts for cranberries and 11.7 watts for blueberries. Conclusion. The research increased the economic efficiency of the technological process of natural extraction, which can reduce the cost of the finished product and increase its availability. The values of the process parameters can be used to design new similar devices and serve as practical recommendations for berry extraction in vibration tray devices.

Numerical Investigation of the Secondary Swirling in Supersonic Flows of Various Nature Gases

Despite the application of vortex tubes for cooling, separating gas mixtures, vacuuming, etc., the mechanism of energy separation in vortex tubes remains an object of discussion. This paper studies the effect of secondary swirling in supersonic flows on the energy separation of monatomic and diatomic gases. The approach used is a numerical solution of the Reynolds-averaged Navier-Stokes equations, closed by the Reynolds Stress Model turbulence model. The modelling provided is for a self-vacuuming vortex tube with air, helium, argon, and carbon dioxide. According to the results of the calculations, the effect of secondary swirling is inherent only in viscous gases. A comparison was made between obtained total temperature difference, the level of secondary swirling and power losses on expansion from the nozzle, compression shocks, friction, turbulence, and energy costs to develop cascaded swirl structures. Our results indicate that helium and argon have the highest swirling degree and, consequently, the highest energy separation. Moreover, it can be concluded that the power costs on the development of cascaded vortex structures have a significant role in the efficiency of energy separation.

Development of Strategies to Reduce Ventilation and Heating Costs in a Swedish Sublevel Caving Mine—a Unique Case of LKAB’s Konsuln Mine

This paper outlines a unique case of the development of strategies to reduce ventilation and heating costs in Konsuln iron ore mine in northern Sweden. The mine, located just south of Luossavaara-Kiirunavaara Aktiebolag’s Kiruna iron ore mine, was developed as a test mine 2018–2020 for the Sustainable Underground Mining (SUM) project. Besides functioning as a test mine, Konsuln also contributes ore production. The existing mine ventilation system was designed for the current production rate of 0.8 million tons per annum (Mtpa). There is a plan to increase this rate to between 1.8 and 3 Mtpa in the future, and this requires the primary fans to be upgraded. Therefore, a study was carried out to determine whether using ventilation on demand (VOD) could avoid this fan upgrade and reduce Konsuln’s ventilation and heating power costs in the future. The study also investigated whether using battery electric vehicles (BEVs) along with VOD or as a standalone strategy could further reduce these power costs. In addition, the study analyzed the suitability of heating power reduction strategies presently or previously used in the Nordic countries and Canada to investigate potential additional strategies to reduce the heating power cost, the largest portion of Konsuln’s ventilation and heating power costs. The study found using VOD can avoid the expensive upgrading of the existing primary fans and reduce Konsuln’s ventilation and heating power costs in the future. Using BEVs can further reduce these costs. Finally, none of the Nordic and Canadian heating power reduction strategies is suitable for Konsuln because they require unique conditions that do not exist in Konsuln.

Model investigations into assessing optimal power consumption modes for major pump stations of iron ore underground mines

The article investigates into the level of energy efficiency of main water pump stations of iron ore underground mines in case of time-of-day electricity rate. There are developed and suggested methods of analyzing the influence of pump electric capacity on electricity cost based on multifactor regressive models. The data on power consumption of iron ore mines indicates a complex character of analyzing the results obtained. However, application of information technologies enables using static materials in a new way including indices of power consumption, costs, water intake, mining depth, the number of pumps and their capacity by synthesizing mathematical models as complicated objects through in-depth procession of static materials and substantiation of the obtained results. For the first time, there are used multifactor regressive models considering multicollinearity and non-linearity of pump capacity in order to study its influence on power costs by using the elasticity factor. Analysis of mathematical simulation results relevant to static materials and applying the algorithm of studying dependency of the consumed power costs on pumps’ capacity reveals some critical values resulting in corresponding effects. The authors recommend to apply the elaborated algorithm to conducting corresponding calculations by for mining enterprises to monitor formation of the strategy of providing energy efficiency under time-of-day electricity rates.

Mathematical model of high-temperature tube-shaped pasta drying in a conveyer belt drier

The drying procedure is a key to producing pasta of intended quality and with a specific price tag. However, the existing models are mainly to describe the drying process in a steady state. A mathematical model of tube-shaped pasta drying in a conveyor belt dryer with a stepwise heating supply allows determining the curve of temperature and moisture gradients for a tube-shaped pasta unit. It also helps select the best settings to minimize the heat-power costs while maintaining the good quality of a dried product. The given model describes the drying process in a true-to-life form and ensures the convergence of calculations to observations (deviation: 12.5%). The model was utilized to design a transient drying protocol for conveyor belt dryers with a stepwise heating supply. The proposed dryer has high service reliability and produces uniformly dried high-quality product.