Absorption Chillers to Improve the Performance of Small-Scale Biomethane Liquefaction Plants

Biomethane liquefaction may help decarbonization in heavy transportation and other hard-to-abate sectors. Small-scale liquefaction plants (<10 ton/day) are suitable for small biogas plants located near farms and other agricultural activities. “Internal refrigerant” refrigeration cycles (e.g., Kapitza cycle) are often proposed for small-scale natural gas liquefaction due to their simplicity. An optimized Kapitza-based cycle is modeled and simulated, and then several modifications were studied to evaluate their influence on the energetic and economic performances. Results showed a specific consumption ranging between 0.65 kWh/kg and 0.54 kWh/kg of bio-LNG with no significant improvements by increasing cycle complexity. Instead, a reduction of 17% was achieved with the implementation of absorption chillers, that effectively turn waste heat into useful cooling energy. An economic assessment was finally carried showing that the Levelized Cost of Liquefation is more affected by electricity cost than additional CapEx.

SPECIFIC FEATURES OF DETERMINING THE DESIGN OF OXYGEN TUBE TIPS UNDER NON—STATIONARY CONDITIONS OF CONVERTER MELT WITH PRELIMINARY HEATING OF SCRAP

The results of calculating the parameters of the tips of oxygen lances, taking into account the preheating of scrap metal in the converter due to the combustion of solid fuels in the modern raw material conditions of a metallurgical enterprise of Ukraine, are presented. The substantiation of the design of blowing devices is provided. The results of calculating the geometric parameters and the coefficient of off-design for standard and experimental tips of oxygen lances are presented. Using numerical methods, the value of the diameters and length of the supercritical part of the nozzle was obtained. It is shown that with a decrease in the blast flow rate, it is advisable to decrease the length of the supercritical part of the nozzle, which is fully correlated with the literature data. The change in the coefficient of off-design was determined for the studied range of oxygen consumption (600—1100 m3 / min) for standard and experimental handpieces. It is shown that the value of the coefficient of off-design is in the range of 0.52—0.98 and 1.30—2.30, respectively, for 5– and 6–nozzle standard tips. For experimental tips, this figure is 1.00—1.70. Tuyeres with experimental tips, at the pressure available in the shop, reliably operate in the range of oxygen consumption 650—950 m3 / min and allow increasing the oxygen consumption at the beginning of the blowdown to 1000—1100 m3 / min and more, if necessary. The resulting saving effect from the introduction of the modernized tips is: a decrease in the oxidation of the final slag 1.22—1.70 %; reduction in the specific consumption of lime 0.29—1.81 kg / t; reduction of specific consumption of metal charge 0.26—0.38 kg/t.

Forecasting of the efficiency indicators of the use of boiler and furnace fuel in the non-traction power engineering of railway transport based on the model of temporaryth row

The article considers the solution of the problem of constructing forecast values for a long period of changes in the value of the specific consumption of boiler and furnace fuel by boilers for a geographically distributed company-Russian Railways, taking into account the use of various types for the main types of fuel used in the generation of thermal energy: natural gas, heating oil, coal and brown coal. A mathematical model based on time series using the Bollinger method is proposed, which includes elements of extrapolation and modeling. An example of calculating the change in the values of specific consumption in the future until 2035 in the whole railway network is given. A simulation of the change in this value is performed for the variant fractions of substitution of one type of fuel with another. The possibility of determining long-term forecast indicators using a time series model is shown.

EXPERIMENTAL STUDY OF THE ENERGY PERFORMANCE OF NANSU STOVE WITH A MODIFIED GRID BY THE CONTROLLED COOKING TEST

The present work concerns the modification of the grid of the Nansu stove, used in many households in Africa and in particular in Benin. The performance of the stove obtained (modified Nansu) was estimated and compared on the one hand with that of the corresponding reference stove and on the other hand with that of the ordinary Nansu stove. To do this, the Controlled Cooking Test (CCT) was used to determine the specific fuel consumption and cooking time for three dishes, namely rice, beans and voandzou. The results of these tests show that the modified Nansu fireplace is significantly more economical, in terms of fuel consumption and cooking time, compared to the ordinary Nansu fireplace. The savings made by the modified Nansu stove compared to the ordinary Nansu stove are 34.57% to 64.31% in specific consumption and 9.42% to 37.81% in cooking time depending on the type of dish.

Mathematical modeling of technological process in formalin production

Methods and algorithms of the sustainable synthesis of adaptive control systems for the technological process of formalin production have been proposed in this article. Parameters of the regulator are estimated in the developed adaptive control system, i.e. the purpose of adaptation is reduced to the estimation of coefficients of the regulator providing the specified behavior of the system. The results obtained and the analysis of transition processes based on the modeling of the control system showed that with adaptive control, mass fractions of formaldehyde and methanol in formalin are held within 36.5÷37.5% and 0.7÷0.9% respectively, while the specific consumption of the methanol decreases by 3÷4%, which allows the process in mode close to the optimal.

Energy Efficiency of Buildings in Arctic Regions of the Russian Federation

This article considers a pressing issue to be addressed by those responsible for the energy efficiency management in the Arctic Regions of the Russian Federation. It presents examples of successful solutions to related problems that can be used by energy efficiency program developers in specific regions. This article reviews the introduction indicators for energy-efficient technologies and the specific consumption values for thermal energy. The monitoring of energy-saving and improvement of energy efficiency across the economic sectors is performed using the specific consumption values of fuel and energy resources. The main causes of the excessive consumption of thermal energy include the maladjustment of heating systems, excessive consumption of hot water in hot water supply systems, low heat-proof properties of the structural surfaces of buildings, and heat losses during heat carrier transport due to the low quality of pipeline insulation.

Modified Concrete Mixes for Monolithic Construction

The effect of the multifunctional supplement Linamix PCX and mineral fillers of microsilica and expanded clay dust on the characteristics of concrete mixtures pumped by concrete pumps is investigated. The evaluation of highly mobile and self-compacting concrete mixtures’ properties was carried out according to pumpability criteria that simulate the elastic-viscous structured system flow. The physical and mechanical characteristics of the hardened concrete were determined using standard and generally accepted methods. The ability of the modified concrete to resist tensile stresses was determined by the crack resistance coefficient. The water-reducing efficiency of the superplasticizer was evaluated by the specific consumption of cement per unit of concrete strength. The performed studies have established that the polyfunctional superplasticizer Linamix PCX is an effective modifier of concrete mixtures, rheologically compatible with cements of various material composition. A significant effect of the fine aggregate grain size composition on the properties of highly mobile concrete mixtures and the formation of the hardened concrete structure has been revealed. Evaluation of the modified concretes’ strength characteristics showed that it is rational to use the mixtures with Linamix superplasticizer PCX and microsilica, providing high strength concrete with a minimum specific consumption of cement for concreting massive monolithic structures in order to slow down heat generation during concrete hardening.

Using MVDA with Stoichiometric Balances to Optimize Amino Acid Concentrations in Chemically Defined CHO Cell Culture Medium for Improved Culture Performance

Chemically defined (CD) media are routinely used in the production of biologics in Chinese Hamster Ovary (CHO) cell culture and provide enhanced raw material control. Nutrient optimized CD media is an important path to increase cell growth and monoclonal antibody (mAb) productivity in recombinant CHO cell lines. However, nutrient optimization efforts for CD media typically rely on multi-factorial and experimental design of experiment (DoE) approaches or complex mathematical models of cellular metabolism or gene expression systems. Moreover, the majority of these efforts are aimed at amino acids since they constitute essential nutrients in CD media as they directly contribute to biomass and protein production. In this study, we demonstrate the utilization of multi-variate data analytics (MVDA) coupled with amino acid stoichiometric balances (SBs) to increased cell growth and mAb productivity in efforts to reduce CD media development efforts. SBs measure the difference between theoretical demand of amino acids and the empirically measured fluxes to identify metabolic states of the cell. When coupled with MVDA, the statistical models were not only able to highlight key amino acids towards cell growth or productivity, but also provided direction on metabolic favorability of the amino acid. Experimental validation of our approach resulted in a 55% increase in total cell growth and about an 80% increase in total mAb productivity. Increased specific consumption of stoichiometrically balanced amino acids and decreased specific consumption of glucose was also observed in optimized CD media suggesting favorable consumption of desired nutrients and a potential for energy redistribution towards increased cellular growth or mAb productivity.

Streptomyces biomass – effective additive in poultry nutrition

Introduction. The breeding of domestic poultry is an important source to soupplement the human needs in animal proteins with a high biological value. Therefore, knowledge and guidance of the factors that influence poultry production is a guarantee of increasing these productions, both in terms of quantity and quality.Material and methods. The investigation was aimed to administer the 0.05% and 0.1% streptomyces biomass in the recipe of combined fodder, intended for the feeding of young poultry of the Argintie de Adler breed, in order to identify the effectiveness of its administration.Results. The supplementing of streptomyces biomass in the proportion of 0.1% in the recipe of combined feed intended for feeding the poultry of the Argintie de Adler breed, contributed to a 5.1% gross weight gain and a lower specific consumption by 9.9% in chickens from the experimental batch, compared to those of the control batch.Conclusions. The assessment of the dynamic indices of growth and development in chickens of the Argintie de Adler breed, as a result of supplementation of nutrition recipes with streptomyces biomass, has established a sure way to boost the productivity.