Modeling and Investigation of Multistage Flash-Mixing Brine in Aqaba City, Jordan

Desalination processes are considered an essential solution to meet the water scarcity in Jordan. Among the desalination techniques, the multistage flash (MSF) desalination technique has a significant contribution to water budget in many regions around the world. In this paper, MSF with a mixing brine desalination plant was proposed in Aqaba city of Jordan. The plant will consume 5 MW power to produce about 74 Kg/s of freshwater. Different designs are studied to determine the most appropriate design. Also, the effect of feed sea water flow rate, heating steam flow rate and number of stages on the plant performance were evaluated. The optimum layout consists of 24 stages with 3.6 m width, 2.6 m length, and with a recycled brine flow rate of about 651 Kg/s. The expected plant performance is 9.6.

Application of a Two-Stage Steam Jet Injector Unit for Latent Heat Recovery of a Marine Steam Turbine Propulsion Plant

The paper presents the results of the numerical research of the steam jet injector applications for the regenerative feed water heating systems of marine steam turbine propulsion plants. The analysis shows that the use of a single injector for a single heat exchanger results in a relative increase in the thermal efficiency of the plant by 0.6–0.9%. The analysis also indicates the legitimacy of the usage of multistage feed water heating systems, which would enable the operating parameters optimization of the injectors. The obtained steam pressure up to the value of 1.8 barA allows for the heating of the feed water up to 110 °C. For higher degrees of feed water heating in the heat exchangers, it is necessary to supply heating steam of higher pressure. Therefore, the usage of two-stage steam jet injector units was considered advisable for the analyses.

Improving the massecuite crystallization in sugar production

The article discusses the concepts of continuous vacuum apparatus operation: vertical VKT (VKT – Verdampfungs-Kristallisations-Turm) and horizontal cascade of VKH vacuum apparatus (VKH —horizontal vacuum pan) from BMA (Germany). The advantages and features of the vertical continuous vacuum apparatus VKT are shown, as well as the possibilities for increasing the efficiency of the product department of sugar factories. Thanks to the special design of the crystallization chambers, the low massecuite level above the heating chamber and the use of mechanical stirrers in each chamber, the VKT apparatus can operate without difficulty with a very small temperature difference between heating steam and massecuite, as well as with an absolute heating steam pressure well below 1 bar. With optimal use of VKT vacuum apparatus, a variety of energy-saving schemes can be implemented, for example, double-effect evaporation in the crystallization section. Part of the secondary crystallization steam is used to heat one of the VKT units, which saves the heating steam of the evaporator unit used for this purpose. With an increase in the productivity of the sugar factory, it is possible to quickly equip the VKT apparatus with an additional chamber. The device works continuously throughout the season, especially with products with massecuite purity of more than 94%. The chambers are cleaned without stopping the entire apparatus. The boiling of massecuite of all stages of crystallization in VKT devices ensures a uniform operating mode of the food compartment, allows to achieve an increase in sugar yield and helps to reduce steam consumption at the plant.

Proposal for modernization of Robert evaporators

It is proposed to convert existing Robert evaporators into Trebor evaporators. Trebor evaporators work as falling film evaporators with the well-known thermal and technological advantages. When converting a Robert evaporator into a Trebor evaporator, the heating steam inlet and the vapour outlet as well as the condensate drain remain in their original positions. If necessary, the positions of the juice inlet and outlet nozzles are changed, and two additional nozzles and a circulation juice pump are required. These changes are cheaper than installing a new falling film evaporator.

Simulation of a single-stage evaporator system integrated with a mechanical vapor compressor for concentrating the electrolytic system KNO3 – H2O

A simulation of a single-stage evaporator system integrated with a mechanical com- pressor for a case study (concentrating the electrolytic system KNO3 – H2O) was performed. A mathematical model of the subsystem of a single-stage evaporator, a mechanical compressor, and superheated steam seeding is presented. Microsoft Excel with VBA (Visual Basic for Application) was used to solve the mathematical model. The model was solved by an iterative method where the values of the in- let stream temperature and the salt concentration in the concentrated stream at the evaporator outlet were assumed. The process parameters of the system have been determined. Since the goal of any industrial process is to minimize costs and maximize products, the impact of mean temperature difference changes on satu- ration water consumption and molar salt content in the concentrated stream was presented. 106.92 kg/h of freshwater are required to obtain 18% by weight of salt in a concentrated stream, while 432.30 kg/h of fresh water are required to obtain 25% by weight of salt in a concentrated stream. Consumption of heating steam ranged from 1760.31 to 4473.4 kg/h depending on the average temperature dif- ference. By increasing the temperature differences from 10 to 25 ◦C, the amount of transferred upper lines increases from 1025 to 2750 kW, which is an advantage of increasing the mean temperature difference. The disadvantage of the larger tem- perature difference is the increase in the power of the mechanical compressor from 97.02 to 384.12 kW.

MODELLING OF METHYLAMINE RECTIFICATION PROCESS

The article considers the results of the survey and simulation of the unit for rectification of metilamines in the conditions of JSC "ANHK" with the issuance of recommendations on replacement of internal contact devices, change of material flows and decommissioning of two rectification columns. The implementation of the recommendations allowed to ensure continuous operation of the plant and to reduce the costs of heating steam, electricity and water

TECHNOLOGY OF CYCLIC DISTILLATION IN ALCOHOL PRODUCTION

Alternate changing of the steaming periods and liquid overflow allows to intensify mass transfer between liquid and steam and to reduce the specific consumption of heating steam in the process of separation of multicomponent mixtures. Known methods and models have not found widespread practical use due to the lack of mass transfer in the steam period, fluctuations in steam pressure in the collector, the complexity of constructive solutions to ensure cyclic mode, etc. The authors propose a technology for rectification, which involves the cyclic motion of the liquid without interrupting of the supply of heating steam and the construction of a rectification column for its implementation. The purpose of the work was to research the effectiveness of the proposed technology in the process of rectification of alcohol-containing fractions and to establish the specific flow rate of steam in the impurity concentration column. To ensure a cyclic mode, the column was equipped with movable liquid transfer devices connected to actuating mechanismes, which acted according to the controller program, and perforated (scale-shaped) trays. The primary task was to determine the hydrodynamic mode of operation of the contact devices - the lower and upper the critical vapor velocity of at which the liquid is retained on the plates and there is its entrainment. It is established that the vapor velocity in the free section of the column can reach 1.2 m/s or more, and in the openings of the scales must exceed the first critical velocity of 6.5-7.5 m/s. The weeping of the tray occurs at the vapor velocity in the holes of 1.5-1 m/s. The investigations were carried out in the production conditions of the Chudniv branch of SE “Zhytomyr liquor producer ”. It is experimentally proved that in the process of rectification of alcohol-containing fractions, the main impurities are removed completely, the degree of extraction of higher fusel alcohols is increased by 38%, methanol - by 15.6 %, the multiplicity of concentration of the main impurities is increased by 25 %, the higher alcohols - by 40 %, methanol – by 34 %, acrolein – by 36 %. The costs of heating steam are reduced by 30 % compared to typical installations and do not exceed 13 kg/dal of absolute alcohol introduced with feed. Exempted from the key impurities the bottom liquid of the impurity concentration column should be used for hydroselection in the purifying column.