Evaporation Plant Research Articles

Techno-economic feasibility study of coupling low-temperature evaporation desalination plant with advanced pressurized water reactor

The increasing demand for freshwater necessitates sustainable desalination solutions, and nuclear power plants offer a promising avenue by utilizing their low-grade waste heat. This study assesses a techno-economic feasibility of coupling a 5 MWth low-temperature evaporation plant with a UAE-based Advanced Pressurized Water Reactor (APR1400). The system addresses freshwater demand, aligning with sustainability goals through low-grade heat utilization. The investigation explores three extraction points for low-grade heat steam, with temperatures ranging from 80 °C to 130 °C. Thermodynamic evaluations using DE-TOP illustrate power requirements and losses, considering variations in maximum brine temperature from 50 °C to 65 °C. Economic analysis using DEEP estimates water production costs. Findings reveal negligible variances in power plant parameters and a minimal reduction in overall efficiency (<0.5 %). The power loss ratio increases proportionally (10 % to 18.6 %) with higher-temperature heat extraction, while the total power requirements for the desalination plant rises by around 30 %, with a negligible power output reduction ratios (0.03 % to 0.07 %). A consistent linear correlation between water production rate and maximum brine temperature doubles water production (∼900 to 1800 m3/day). Applying multiple extraction points across low-grade heat sources demonstrates scalability, reaching three times that of single-point extraction, with marginal increases in power requirements and losses, while maintaining the power reduction ratio below 0.15 %. Economic feasibility indicates competitive water production costs, ranging from 1.53 to 0.87 $/m3 for desalination capacities between 900 and 5400 m3/day. This study provides valuable insights into sustainable water production at the nexus of nuclear energy and desalination, with implications for necessary policy intervention.

Investigation of the inlet useful temperature difference effect on the distribution of hydrodynamic characteristics of the vapor-liquid flow inside the falling-film evaporator heating tube designed for a nitric acid solutions evaporation

We present the results of mathematical modeling of effect of inlet useful temperature difference on the vapor- liquid flow in the heat exchange tube of a vertical evaporating film apparatus, which is designed for evaporation of nitric acid solutions. Distributions obtained along the heat exchange tube length of local values of the: mass flow rate of the fluid and secondary steam, the velocity of the fluid film, the velocity of the secondary steam, the Reynolds criterion of the liquid and vapor phases, the absolute pressure depending on the values of this useful temperature difference. The study was carried out using numerical simulation. To study the effect of the initial useful temperature difference on the hydrodynamics of the vapor-liquid flow, the vertical evaporator equipped with the tube ø38x3 mm and length of L = 4 m was adopted. The linear nature of the distribution of hydrodynamic parameters along the length of the heat exchange tube is established. The absolute pressure in the tube space decreases along the heating tube due to pressure drop. The limiting factor in reducing the absolute pressure is the friction losses of the secondary vapor on the solution film surface. A decrease in the pressure in the tube space leads to decrease in the boiling point of the solution. This leads to increase useful temperature. This has a positive effect on the evaporation efficiency The obtained data should be used in the design of evaporation plants, which are designed for evaporation of nitric acid solutions.

EVATool: A novel software for aiding in operational decision-making of evaporation plants in kraft pulp mills

The energy recovery capability of a kraft pulping process is crucial for its feasibility, and the evaporation process of black liquor is very important for a successful energy recovery since it is the first stage of the recovery system. Despite the apparent simplicity of the process, black liquor evaporation involves multiple evaporators and complex unit operations. Therefore, analyzing and simulating different operational scenarios is essential before proposing changes. A new software tool was developed to address the limited offer of specific software for analyzing black liquor evaporation plants. It focuses on fast analysis of these plants by estimating the heat transfer coefficient, steam consumption, steam economy, black liquor mass fraction between effects, and others. The tool was developed in Python and provides an interface resembling the supervisory system used by operators and offers equipment widgets for creating plant diagrams. EVATool also presents a dashboard for easy visualization of the main results. Software validation using examples of evaporation plants has confirmed its capability to simulate plants in different modes. In an industrial setting, the dashboard enables the comparison of simulated values with project indicators unavailable through operational instrumentation. While improvements are possible, this software shows great potential for industrial implementation, contributing to operational decision-making in daily operations of the evaporation process in pulp mills.

ПОВЫШЕНИЕ ЭФФЕКТИВНОСТИ РАБОТЫ ТЭЦ ПАО «ГАЙСКИЙ ГОК» ЗА СЧЕТ ДОЗАГРУЗКИ ТУРБОАГРЕГАТОВ

Competitiveness of Gaysky GOK depends on energy costs, including the purchase of electricity for technological needs. Turbine units additional load is often considered in the context of optimization of power plant operation under changing conditions of electricity demand. By increasing the turbine load at certain times or when necessary to respond to changes in grid load, it is possible to improve resource utilization efficiency and reduce power generation costs. This article describes the methods of increasing the efficiency of steam-turbine units of thermal power plant of PJSC "GAYSKiy GOK", due to additional loading of operating turbine units up to nominal capacity. At low cost of electricity produced by the CHPP, compared to electricity purchased on the wholesale electricity market, which will reduce the company's costs for electricity purchase. &#x0D; Steam, which is produced during the operation of turbine units in nominal mode and in the winter period is used for heating the city, in the fall-summer-spring periods it is proposed to use for the operation of evaporator plant, which will be used for desalination of clarified water, which after processing will be used in the technological process of the CHPP itself, as feed water for boilers, which will eliminate the need for water treatment of the CHPP.

SCADA project for milk evaporation in double-effect evaporators

Human-machine interface tools remain one of the components of production automation systems. Appearance and functional abilities cannot stand still in the same way as automation, in this regard, one of the important aspects of food production automation is highlighted in this paper – a human-machine interface aimed at improving the operator's workplace. At the dispatcher level of automation, it is necessary to provide for the solution of the entire range of tasks set during the implementation of this project. The objectives of the project are to reduce the time for decision-making by personnel, since the effectiveness of the enterprise partially depends on the speed of the task, notification of hazards and violations, as well as the prevention of emergency and abnormal situations during the evaporation of milk, storage and archiving of data on the course of the process necessary for the preparation of reports used to investigate the causes of any emergency when evaporating milk. The project of the human-machine interface of the milk evaporation process, developed in the TRACE MODE environment, is presented. A feature of TRACE MODE is the technology of a single programming line, that is, the ability to develop all the ACS modules using a single tool. In the developed project of the human-machine interface of the milk evaporation process, it is assumed to use two main operator stations and one backup. Two of them are for operator workstations and a backup one used in emergency situations. The developed project in the TRACE MODE environment makes it possible to improve the workplace of the operator of the vacuum evaporation plant, reduce the time required for response and decision-making by personnel. In addition, the automatic alarm system allows you to reduce the number of defective products, and, accordingly, increase output and reduce the cost of production per unit of raw materials. The developed project fully satisfies the technical task and has been put into production.

Bagasse dust exposure and chronic respiratory symptoms among workers in the Metehara and Wonji sugar factories in Ethiopia: a longitudinal study design

BackgroundEthiopia’s sugar factories are growing by creating job opportunities for thousands of workers with varying educational, professional and socioeconomic backgrounds. These sugar factories are a source of several hazards that...

Enhancing industrial vertical falling film evaporation through modification of heat transfer surfaces – an experimental study

In this study we introduce and experimentally study modifications of heat transfer surfaces as a means to improve the heat transfer in evaporative vertical falling film units. We look at two modified tubular surfaces and compare the obtained results to those acquired using a similar smooth surface. We carry out experiments with two fluids of significantly different viscosities and work with a broad range of industrially relevant operating conditions, with Kapitza (Ka) and Reynolds (Re) numbers in the range of Ka = 500–10 000 and Re = 100–2 000, respectively. We find that the heat transfer rate in a pilot-scale unit can be improved by 50% to more than 100%, depending on geometrical features (e.g. sharpness) of the modified surface. Our results pave the way for increasing the overall efficiency of industrial evaporation plants by increasing the energy intensity of the evaporator per unit area through carefully tailored modifications of heat transfer surfaces.

Techno-economic analysis of hydrothermal carbonization of pulp mill biosludge

For many mills, the biosludge from wastewater treatment is difficult to recycle or dispose of. This makes it a challenging side stream and an important issue for chemical pulping. It often ends up being burned in the recovery or biomass boiler, although the moisture and non-process element (NPE) contents make it a problematic fuel. Biosludge has proven resistant to attempts to reduce its moisture. When incinerated in the biomass boiler, the heat from dry matter combustion is often insufficient to yield positive net heat. Mixing the sludge with black liquor in the evaporator plant for incineration in the recovery boiler is more energy efficient, but is still an additional load on the evaporator plant, as well as introducing NPEs to the liquor. In this study, treating the biosludge by hydrothermal carbonization (HTC), a mild thermochemical conversion technology, is investigated. The HTC process has some notable advantages for biosludge treatment; taking place in water, it is well suited for sludge, and the hydrochar product is much easier to dewater than untreated sludge. In this study, two HTC plant designs are simulated using IPSEpro process simulation software, followed by economic analysis. Low temperature levels are used to minimize investment costs and steam consumption. The results show that if the sludge is incinerated in a biomass boiler, payback periods could be short at likely electricity prices. The HTC treatment before mixing the sludge with black liquor in the evaporator plant is profitable only if the freed evaporator capacity can be used to increase the firing liquor dry solids content.

Моделирование и расчет процесса тепломассообмена в многоступенчатых многопоточных испарителях мгновенного вскипания

Thermal methods that have several environmental and economic advantages are widely applied for water treatment at thermal (TTP) and nuclear power plants (NPP) along with chemical methods. Multistage flash evaporation plants are important in case of use of thermal methods for desalinated water treatment as they can use low-temperature steam of thermal power plants. Despite the considerable number of scientific papers on this issue, the effective performance and improvement of the heat and mass transfer process in evaporator plants remains an urgent task, especially with variable operating modes of the technological equipment of TPPs and NPPs. On the one hand, it is due to the need to match the variable parameters of steam and the variable flow rates of make-up water for the process needs of the station. On the other hand, it is due to the lack of universal methods to calculate and design the equipment. Thus, the development of new methods to model and improve heat and mass transfer processes in thermal water treatment plants of thermal power plants and nuclear power plants is an urgent task for the power energy industry and related ones. To solve the problems of modeling heat and mass transfer processes in flash evaporation plants, models based on the mass and energy balance equations have been used. The obtained differential and linear equations are solved by analytical methods and methods of mathematical programming. A matrix model of the process of heat and mass transfer in a multi-stage multi-flow evaporative flash installation has been developed, considering evaporation of part of the water when it enters the low-pressure region. The steady-state pressure distribution over the stages and the performance of each stage of the evaporative installation have been found. Comparison of the calculated and known results have shown an adequate description by means of the model of the real process of heat and mass transfer in flash evaporation plants. It makes possible to set and solve problems to choose the optimal design and operating parameters of equipment for multi-flow evaporation plants. The proposed method to solve the problem of modeling heat and mass transfer provides the possibility of simultaneously search for acceptable values of design and operating parameters of multistage evaporative plants for various purposes.

THE INFLUENCE OF PROCESS PARAMETERS ON BROWN STOCK PULP WASHING AT NATRON-HAYAT MAGLAJ

Brown stock washing is one of the major unit operations within the pulp manufacturing business. Poor operating washers have the potential to significantly and negatively affect almost every other area of a pulp and paper mill, including the mill’s environmental performance. The objective of the pulp washing is to remove the soluble impurities such as organic solids (lignin), fines, inorganic solids (Na, Mg, Ca, and K ions), and byproducts after each processing step. The present paper attempts to look at various parameters influencing pulp washing at Natron-Hayat Maglaj to ensure a complete understanding of the process. The results showed for this mixture of raw materials (15 % pine and 85 % fir) that the most influential parameters are Kappa number and dilution factor. Working with a high Kappa number above 50 requires additional equipment. Online control of the dilution factor would further improve the quality of the washing process and provide additional saving water and savings at the Evaporation plant. The First step for the future to improve the washing of unbleached kraft pulp is the optimization of the washing process through advanced control.

Energy-efficient vacuum evaporation units for concentration in the dairy industry

The application of various types of evaporation plants for concentration of solutions was analyzed. It was noted that the most promising for thickening dairy products are film-type vacuum-evaporation units with mechanical compression of secondary steam. The heating chamber of the evaporator is made in the form of a vertical shell-and-tube heat exchanger with the supply of heating steam into the intertube space and with the downward movement of product solutions in the vertical boiling tubes. Based on the analysis of known studies on hydrodynamics and heat exchange of film processes (condensation, film heating and evaporation and steam separation), a conclusion was made about the lack of data for calculating pressure losses in the steam circuit of the evaporator with sufficient accuracy. To solve this problem, improved methods of calculating the hydraulic resistance of the intertube steam path of the heating chamber and the two-phase flow of the product film and secondary steam in evaporative boiling tubes have been developed using the published results of hydrodynamic resistance research. Pressure losses for the movement of secondary steam in the lower chamber of the evaporator include losses for acceleration of the steam released from the falling film of the product. It is shown that the hydraulic depression of the movement of steam in the intertube space of the heating chamber, depending on the type of scheme, can be from 2.3% to 77% compared to the working temperature pressure of the heating surfaces. The four-way flow scheme of the heating steam used in the design of the vacuum-evaporation unit ensures a reduction of hydraulic losses by up to 15%. A technical and economic analysis of the costs of operating a vacuum-evaporation unit with a productivity of 10 t/h of vaporized steam was performed, according to which the lowest reduced costs were established at a temperature drop of 5˚C on the compressor. The results of the research were used in the development of structures and the manufacture of vacuum-evaporation units with mechanical and mixed (mechanical and thermal) compression at PrJSC "Kalyniv Machine-Building Plant" (Kalynivka, Vinnytsia Region). 10 vacuum evaporation units with a capacity of 5 to 20 t/h of evaporated moisture were manufactured and put into operation.

System thinking in the analysis of the juice evaporation plant in the food industry

The article is devoted to the system analysis of evaporation of solutions. The existing evaporation apparatus has been studied by dividing into quasi-apparatuses: the heating chamber, the wall of the boiling pipes of the heat-transmitting evaporation apparatus, the vapor-liquid space - the inner part of the boiling pipes of the evaporation apparatus. Studies of the evaporation object have a stable character with a change in the concentration of the outgoing solution.

An integrated approach to solving the technological problem of obtaining target cathodes from transition metal silicides for vacuum ion‑plasma sources

The article discusses the technological principles of improving the manufacturing process of consumable cathodes-targets of vacuum electric arc evaporation plants from complex silicides. Which are based on: the selection of chemical composition based on the analysis of state diagrams of double and triple systems, the production of fast-cooled ingots using high-speed induction melting, subsequent grinding and grinding to a powder of the required fraction, static or dynamic pressing of the cathode blank, its sintering and soldering of the current guide. The results of laboratory studies of the process are presented and prototypes of products are obtained.

Порівняння роботи підсистем прогнозування в автоматизованій системі керування випарним апаратом

Мета дослідження — обґрунтування методів регулювання тиску пари у випарному апараті з підсистемою прогнозування, що дозволить спрогнозувати поведінку системи та дослідити вплив кількості часових інтервалів алгоритму прогнозування на точність прогнозу роботи випарної станції. Розроблено систему обміну даними між рівнем технологічного процесу і рівнем виробництва. Досліджується робота випарної установки з підсистемою прогнозування регулювання тиску пари. У схемі автоматизації регулювання тиску пари як датчик використовуються перетворювачі тиску PC-28. Виконавчими механізмами служать пневматичні сідельні клапани з вбудованим дроселем та електро-пневмоперетво­рювачем. Використання нейронечітких регуляторів відбувається лише в окремих специфічних випадках інтелектуального керування процесом випаровування, відсутні дані порівняння застосування інтелектуальних регуляторів з класичними, можливості комбінування роботи кількох типів інтелектуальних регуляторів, а також чітких засобів прогнозування їх роботи. Тому у даній роботі використано метод прогнозування для порівняння методів регулювання тиску пари в апараті, що дозволило спрогнозувати поведінку системи при формуванні керування та вивести готовий прогноз на екран оператора і, таким чином, підвищити ефективність роботи випарної станції. Зібрано статистичні дані поведінки контурів системи автоматизації у різних режимах роботи з використанням інтелектуальних та класичних регуляторів і побудовано модель прогнозування роботи випарної станції методом локальної тенденції та модифіковано алгоритм прогнозування. Перевага даного методу — легка і швидка його реалізація, яка не потребує великих економічних та енергетичних затрат. Побудовано модель прогнозування роботи випарної станції методом локальної тенденції та розроблено алгоритм прогнозування. Також оцінено точність отриманої моделі прогнозування: 97 % — для ПІД-ре­гулятора, 97 % — для нейронечіткого регулятора та 96,5 % — для нейромережевого при використанні девʼяти інтервалів, що вище за точність при використанні шести інтервалів. Запропонована модель для прогнозування роботи випарної станції характеризується високою точністю в цілому, але під час коливань у перехідному процесі виникає несуттєве запізнення їх прогнозування. Точність роботи даної моделі напряму залежить від збільшення кількості часових інтервалів при розробці алгоритму прогнозування.

Application of intensive technologies for improved production processes in poultry farms

One of the important problems in the modern world is to provide the population with high-quality food. So, today the agricultural sector faces the main task of increasing the production of agricultural products, as well as the use of agricultural waste. Poultry farming is one of the main branches of the agricultural sector. The main task facing farmers is to improve the conditions and technology for feeding and keeping farm birds, and one of the important tasks is the state of indoor air in this regard, the problem remains open. Therefore, the main way to solve this problem is the preferred transition to intensive technologies in order to realize the efficiency potential in poultry farming. However, the intensification of the area increases the anthropogenic load on the environment. The main source of environmental risk is the systems of disposal of bird droppings. Our research has shown that 85 % of the negative impact on the environment is caused by poultry and animal husbandry waste. Lighting also plays an important role in poultry farming. Thus, lighting is the basis for electricity consumption. Both natural and industrial lighting is important for the physiology of birds and their development, but, unfortunately, it is quite energy-intensive. In this regard, the idea of solving this problem is being created, it is the development and application of new, efficient, inexpensive and environmentally friendly technologies that are important for large-scale research. Therefore, it is necessary to take into account that most poultry farms are equipped with simple mechanical ventilation systems without cooling. So, an increase in productivity is possible through the introduction of intensive technologies, while the economic assessment of the use of evaporation plants, the disposal of bird droppings and LED lighting can be of practical importance.

Improving Kraft Pulp Mill Energy Efficiency through Low-Temperature Hydrothermal Carbonization of Biological Sludge

Of the various waste and side streams created in a kraft pulp mill, the biological sludges from the wastewater treatment plant are some of the most problematic to handle. Incineration is becoming a common solution as landfilling is no longer permitted by legislation in many countries, but this is also problematic due to the high moisture content, poor drying characteristics, and high ash content in the solids. This study evaluates the technical potential of mild hydrothermal carbonization (HTC) at 160 °C for 3 h to improve the energy efficiency of on-site incineration as a biosludge handling method. HTC treatment transforms wet organic substrates into a hydrophobic carbonaceous material (hydrochar). The heating value and elemental composition of both the sludge and the hydrochar product were analyzed. Based on this, a hydrothermal carbonization model developed earlier was adjusted for the feedstock, and process integration modelling performed to evaluate the performance impact on the power and heat generation at the mill. The results indicate that if the alternative is combustion in the power boiler, HTC pre-treatment could allow a significant increase in power generation. If the sludge is combusted in the recovery boiler, a practice often avoided in order to not introduce non-process elements to the chemical recovery cycle but sometimes necessary due to, e.g., absence of a power boiler, a much smaller increase is obtained. The increase is smallest if the freed evaporator plant capacity cannot be utilized for increasing the firing liquor dry solids content.

Solubility of sodium oxalate in kraft black liquors below 100°C

AbstractPrecipitation of sodium salts from kraft black liquor leads to scale formation in the evaporation plants of kraft pulp mills. Sodium oxalate scaling is most prevalent in mills pulping tropical hardwoods such as eucalyptus and acacia, but it has also been found in the scales in high solids lines after the concentrators in mills pulping softwoods. There is very limited solubility data for sodium oxalate in black liquor, especially below 100°C. This study measures the solubility limit in four different black liquors from 14% to 47% dry solids between 50 and 90°C. The newly generated solubility data in black liquors enhance our understanding of sodium oxalate scale formation in low solids effects of the evaporation plant. An example of an application to a kraft pulp mill with sodium oxalate scaling in the seventh effect is given.

Dynamic modeling of a multi-effect vertical falling-film evaporator for water reuse in CSP plants

This work presents the dynamic modeling of a vertical multi-effect evaporator plant designed and manufactured for its installation at a commercial concentrating solar power (CSP) plant, within the framework of EU H2020 project SOLWARIS (Solving Water Issues for CSP plants). The model has been developed using Modelica computational language and implemented in Dymola® software environment. The results from the validation show a good agreement against the design data, obtaining relative errors lower than 5%. The dynamic response of the plant against external disturbances of the motive steam mass flow rate, feedwater mass flow rate and condenser pressure has been investigated. The main results reveal that increasing the motive steam flow rate by 5% produces a similar increment of the water recovered (5.2%), although the concentrate salinity is raised to an unsafe operation zone (106%) that could lead to scaling issues in the evaporators. The same effect occurs when the feedwater is decreased by 5% from its nominal value, causing a significant rise in the concentrate salinity (163%). In those cases, the simultaneous and proportional variation of the motive steam and feedwater mass flow rates allows maintaining the outlet concentrate salinity far from scale formation limits.

Integrated Process Re-Design with Operation in the Digital Era: Illustration through an Industrial Case Study

This work discusses what should be the desirable path and correct tools for the optimal re-design and operation of processes in the Industry 4.0 framework, as illustrated in a challenging case study corresponding to a complex network of evaporation plants in a viscose-fiber factory. The goal is to integrate optimal design, to improve the existing cooling systems, together with the optimal operation of the whole network, balancing the initial investment with the potentially achievable savings. A rigorous mathematical model for such optimization purpose has been built. The model explicitly considers different structural alternatives as a superstructure for the incorporation of new equipment into the network. The uncertainty associated to future operating conditions is also considered by using a two-stage stochastic formulation. Furthermore, the model is also the base from which a deterministic real-time optimization (RTO) builds upon to support the daily management of the future network operation. The RTO tool suggests the allocation of different products to evaporation plants, the distribution of the cooling water and the suitable number of heat pumps to switch on for optimal economic operation. Design and operation problems are formulated and solved via mixed-integer non-linear programming and the results have been tested with historical plant data.

Production of target cathodes from composite silicides for applying protective coatings using casting and deformation technologies

The article discusses the results of manufacturing multicomponent consumable cathodes of vacuum electric arc evaporation plants. To obtain ingots of complex silicide as a raw material for the manufacture of target cathodes, it is proposed to use induction melting of pure metal charge materials in an argon atmosphere.The method made it possible to obtain ingots of complex silicide with a composition close to the calculated one and a density of at least 93 %. Further forming of the cathode takes place when controlling the powder fractions by their percentage ratio with a pressing force of at least 50 tons. The results obtained are compared with the SHS method of manufacturing cathodes of identical composition.