STUDY OF THE EVAPORATION PROCESS OF MOTHER LIQUORS IN THE PRODUCTION OF POTASSIUM NITRATE

"The aim was to study the influence of the main technological parameters on the process of evaporation off the primary mother liquors of the filtration process of a potassium nitrate suspension formed as a result of crystallization of the conversion solution at a temperature of 0 °C. A theoretical analysis of the system diagram and experimental data established the sequence of the formation of components during the evaporation of mother liquors. At the same time, in the studied intervals of variation of the parameters, potassium chloride is formed first, and then, the joint crystallization of potassium and ammonium chlorides occurs with the continuation of the evaporation process, and when the evaporation degree is more than 30-35%, the joint crystallization of potassium, ammonium and potassium nitrate chlorides occurs. The process analytical parameters influence of the ratio of the primary mother liquor and ammonium nitrate, as well as, the degree of evaporation have been studied. A nomogram has been developed showing the dependence of the input and output parameters on the value of the residual pressure, and it makes possible to determine the values ​​of the evaporation degree at given conditions. "

Automated Drilling Variances Detection Through Smart Alarms System

In a drive to enhance drilling operational awareness, the Real-Time Operations Center (RTOC) has developed a State-of-the-Art event detection algorithm that consistently highlights the deviations of critical parameters by actively comparing real-time values against comprehensive physical models and alerting the users through a dashboard. The process relies on different levels of frequency and severity in order to detect events at their onset and prevent developing into a situation that compromises the operations. The first pillar of the solution consists of deterministic modelling of the expected values for a series of parameters in order to provide the basis for comparison and diagnostics. The main parameters sought to be modelled consist of the Standpipe Pressure, the Rotary Torque and the Hook load, which respectively are generated through individual methods taking into consideration actual conditions as well as relevant contextual data to ensure accuracy. The second pillar of the solution consists of visual alerts, triggered and displayed on a dashboard based on frequency and severity levels, as percentage of deviation from accepted operational envelope. The solution has been initially implemented during drilling operations where different issues were expected to take place, finding that whenever such occurrences took place, the algorithms were able to signal potential events in most of the cases. Some challenges were observed mainly due to sensor calibration and behavior since the expected model values not necessarily match reality, including residual pressure when the pumps are off or when the string is set on slips but the hook load values still present some variance. Also, it has been observed during transient periods where flow and rotation are changed drastically, that the stabilization to a steady state present with high variance, which has demanded the introduction of further logics within the algorithms to account for these effects and avoid the generation of false indications of issues. The solution has given encouraging results thus far in signaling different dysfunctions on the drilling process without the need of immediate human interpretation of data, which has allowed to move forward in the digitalization of operations, not only by timely signaling the onset of issues, but as well by providing the basis to further develop real time diagnosis of the problems to accelerate their resolution. The conception of the event detection based on deterministic real time analysis of individual channels against robust physical models from the existing digital twin solution has proven an immediate asset for operations on its own. By providing clear signaling of issues, while providing a solid framework to ultimately develop a diagnostic solution to translate a potential event into a proactive approach to support decision making process.

Environmentally Friendly Pyrometallurgical Scheme for Vacuum Separation of Non-Ferrous Metals from Waste Products in Incineration Plants

Residues from the municipal solid waste processed in incineration plants in European countries are an important raw material to obtain valuable components, including non-ferrous metals. State and private companies specializing in the processing of waste incineration slag as products most often receive concentrates of non-ferrous metals, which, on average, contain, in mass. %: 20÷60 Cu; 10÷30 Zn; 5÷15 Pb; ~ 1 Al; ~ 1 Sn; ~ 1 Fe, up to 50 g/t Аu and up to 3,000 g/t Ag. Concentrates are sent for processing to smelters without taking the cost of zinc into account. The paper presents the study on the separation of metallic zinc into a separate product (zinc concentrate) from the collective concentrate of non-ferrous metals by a vacuum-thermal method, the safest from the environmental point of view. The study was performed with non-ferrous metal concentrate of +0.3-0.8 mm in size, containing wt. %: 68.07 - Cu; 12.4 - Zn; 14.78 - Pb; 0.99 - Al; 1.2 - Sn; 0.15 - Fe, up to 2.0 kg/t - Ag. The material was heat treated at 800÷900℃ with the residual pressure in the system of less than 0.13 kPa. Zinc concentrate was obtained, containing more than 96% of the main component. At the same time, the Cu content increased by 14.09% in the residue from the heat-vacuum treatment. Other metals (Pb, Al, Sn) including noble metals were also concentrated in the residue. The results of the study show that it is possible to separate zinc into a separate product from non-ferrous metal concentrates containing more than 10% Zn in the initial material by the proposed method.

Analysis of the mathematical modelling of a static expansion system

Static expansion systems are used to generate pressures in medium and high vacuum and are used in the calibration of absolute pressure meters in these pressure ranges. In the present study, the suitability of different models to represent the final pressures in a static expansion system with two tanks is analysed. It is concluded that the use of the ideal gas model is adequate in most simulated conditions, while the assumption that the residual pressure is zero before expansion presents problems under certain conditions. An uncertainty analysis of the process is carried out, which leads to evidence of the high importance of uncertainty in a first expansion over subsequent expansion processes. Finally, an analysis of the expansion system based on uncertainty is carried out to estimate the effect of the metrological characteristics of the measurements of the input quantities. Said design process can make it possible to determine a set of restrictions on the uncertainties of the input quantities.

Improving the Oil-Free Scroll Vacuum Pump Efficiency

Improving the quality of manufactured products involves reducing any contaminants introduced into the vacuum chamber from the pumping means. Scroll vacuum pumps, which are constantly developing, are the most promising for oil-free pumping. Relying on the mathematical model developed, we examined the influence of the main parameters of the scroll on the scroll pump performance, in particular, the influence of the radius of the base circle on the pumping speed and the power consumption of the scroll pump at fixed and variable radii of the pump housing bore. Maintaining the overall dimensions of the pump with an increase in the radius of the base circle proves to lead to an exponential increase in the limiting residual pressure and a decrease in energy efficiency due to a decrease in the number of scroll wraps and, as a consequence, an increase in backflows. For the pump under consideration, when the base circle radius is more than 3.5 mm, the limiting residual pressure exceeds 10 Pa, and the vacuum scroll pump can no longer be a full-fledged oil-free alternative to oil-sealed vacuum pumps. With an increase in the radius of the base circle, while maintaining the number of scroll wraps, the radius of curvature of the outer wraps will increase; this results in the backflow decrease, leading to a decrease, albeit insignificant, in the limiting residual pressure. The energy efficiency of the scroll pump decreases with decreasing pump inlet pressure. The above dependencies make it possible to choose the optimal geometry of the scrolls, based on the specific conditions for which the vacuum scroll pump is designed

Clinical Value of Positive BET and Pelvic Floor Dyssynergia in Chinese Patients with Functional Defecation Disorder

Background Functional defecation disorder (FDD) is a common subtype of functional constipation (FC). Balloon expulsion test (BET) and high resolution anorectal manometry (HR-ARM) are significant tools but their results are not always consistent. Aims To investigate the characteristics of patients with positive BET and pelvic floor dyssynergia (PFD) and explore the value of both positive results in FDD diagnosis. Methods We retrospectively diagnose FC subtypes and enrolled FDD patients based on Rome-IV criteria. They underwent HR-ARM, BET and CTT tests. Then they were classified to 2 groups and further stratified by FDD subtypes. Validated questionnaires were applied to investigate patients’ constipation, anxiety/depression and quality of life. Results 335 FDD patients were finally enrolled. They were classified into 2 groups according to whether BET and PFD were both positive (consistent or not). 84.48% showed consistent results. These patients had significantly higher anal residual pressure, lower anal relaxation rate, MDI and a more negative RAPG (Ps < 0.05). The specific distribution of FDD phenotypes in two groups showed significant difference (P = 0.021). Males suffered a more negative RAPG (P < 0.001) and age was correlated with anal relaxation rate (P < 0.001). 177 individuals among them were investigated with validated questionnaires. Scores for Defecation Symptoms, Physical Discomfort and GAD-7 score were significantly high in Consistent Group (Ps < 0.05). GAD-7 score was associated with Defecation Symptoms (P < 0.001) while anal residual pressure, GAD-7 and Defecation Symptoms score were linked to Physical Discomfort (Ps < 0.05). The diagnostic specificity and PPV for FDD rose significantly with positive BET and PFD. Conclusion FDD patients with positive BET and PFD suffer severe defecation symptoms, anxiety and impaired QOL. Positive BET and PFD could be an ideal tool for screening FDD.

The Degassing Laws for Railway Wheel Steel in a Vacuum Tank Degasser

The research presents the results of data analysis on degassing of wheel grades of steels in a tank degasser with a capacity of 120 tons, operated at the JSC “Ural Steel”. The volume of the analyzed sample included 754 steels for railway wheels (steel grades “2” and “T” according to State standard GOST 10791-2011) weighing more than 80 thousand tons received in November-December 2019.It was established that in order to guarantee the production of hydrogen content of less than 1.5 ppm and nitrogen before 0.007%, it is necessary to carry out vacuum treatment of metal with overheating of 110-130°C at the residual pressure of up to 3 mbar for 20-25 minutes and argon flow rate of at least 0.05 m3/ton. The regression equation was obtained, which allows to predict the results of degassing, as well as select the values of vacuum treatment parameters in order to achieve a given content of dissolved gases - hydrogen and nitrogen.

Late results of surgical treatment of the aortal arch hypoplasia in newborns and babies

Objective. To conduct the analysis of late results of the aortal arch reconstruction in newborns and babies, basing on determination of the risk factors for lethality and reoperations. Materials and methods. In 2010 - 2019 yrs in the Amosov National Institute of Cardiovascular Surgery and Scientific-Practical Medical Centre of Pediatric Cardiology and Cardiosurgery the aortal arch reconstruction was performed in 445 patients, ageing up to 1 year old, suffering coarctation and hypoplasia of one or several aortal segments. Into the investigation were included the patients with a two-ventricular physiology and further two-ventricular correction were included. There were 161 (36.2%) girls and 284 (63.8%) boys with the age median 0.7 mo [0.3; 2.7], while the body mass median – 3.7 kg [3.25; 4.59], and the body surface square median – 0.23 m2 [0.20;0.27]. Echocardiography was the main diagnostic method for the failure as well as for estimation of immediate and late results. Results. Overall lethality have constituted 3.3%, the hospital one – 2.7%, lethality in late period of observation – 0.7%. The observation period have lasted from 1 mo till 9.4 yrs, (2.8 ±2.5) yrs at average. Reoperations on aortal arch were performed in 47 (10.5%) patients: in 12 – surgical aortal arch rereconstruction, in 27 – balloon angioplasty, and in 8 patients both methods were used. The risk factors for lethality after the aortal arch reconstruction in the patients, ageing up to 1 yr old were revealed: the patients’ age on the operation moment lesser than 0.9 mo, the body mass lesser than 2.6 kg, durable operation, presence of concurrent inborn heart failures, residual hypoplasia of the aortal segments A and B. Low mass and the surface square of the body, presence of the aortal arch segments hypoplasia preoperatively, residual pressure gradient on the aortal arch more than 20 mm Hg, hypoplasia of any aortal arch segments after reconstruction have constituted the risk factors for reoperations. Conclusion. Surgical treatment of the aortal arch hypoplasia in newborns and babies is effective and giving good immediate and late results. Anatomic correction of secondary obstruction on the aortal arch level is secure, with low indices of lethality and reoperations, and performed either surgically or endoscopically. Taking into account the risk factors revealed for lethality and reoperations on aortal arch, have permitted to improve the results of treatment of the aortal arch hypoplasia in patients ageing up to 1 yr old.

Development of e-automated control system friction clutch of the vehicle

Problem. One of the most pressing problems of modern automotive industry is to simplify and facilitate driving. As for such a branch of the automotive industry as military equipment. One of the keys to successful completion of the task by the crew of any combat vehicle is the least possible distraction from the process of driving a vehicle and focus on the task. This is possible if the vehicle is provided with relatively comfortable driving conditions, good dynamic properties and the required minimum of controls. The solution to the issue of facilitating car driving cannot be solved without automation of transmission control. Goal. The aim of the project is to create a prototype of an electronic system of automated control of the friction clutch of a vehicle to increase the reliability and efficiency of special and military vehicles. Methodology. Analytical methods of research, program and full-scale modeling, experimental researches on real object of management are used. Originality. New interrelations between the structural elements of the actuator of the friction clutch are proposed, which allow to ensure the required speed of the actuator of the electropneumatic clutch control drive without losing control accuracy when using two electropneumatic valves. The proposed control algorithm of the actuator allows the use of both normally closed valves without residual pressure in the power cylinder. Practical value. The stages of synthesis of the electronic control system are carried out. The algorithm of operation of the tracking system with the use of PID-regulator and taking into account the features of the actuator is proposed and debugged. A new clutch pedal design with an induction sensor is proposed, which provides high accuracy and speed, and also requires only two wires to connect.