Double Effect Evaporator Research Articles

Feasibility of a 1,3-propanediol biorefinery from glycerol using a Clostridium butyricum wild-type strain and its in-silico knockout mutants: A genome-scale metabolic model integration

Advances in computational tools have enabled the development of genome-scale metabolic (GSM) models. Integrating GSM models with downstream processes through multi-scale models allows predicting biorefinery feasibility. This study utilizes the GSM model iCbu641 to predict the use of the wild-type strain Clostridium butyricum IBUN 158B for producing 1,3-propanediol (PDO) from Colombian biodiesel-derived glycerol. Different bioreactor and evaporation trains were evaluated, with the selected biorefinery comprising a fed-batch bioreactor and double-effect evaporation trains. Economic evaluation indicates the selected biorefinery has a payout period of 7.4 years and a production cost of around 1 US$/kg, indicating feasibility. Five additional biorefineries were assessed using in-silico knockout mutants blocking competing co-products. Simulations revealed that blocking hydrogen production could reduce unit costs and payout periods by up to 15 %, suggesting its potential in a PDO biorefinery. Concluding, the novelty of this study is the holistic integration of biological and economic assessments, reducing resources in exploratory experiments.

Study on the effect of volatile organic compounds on the treatment of high-salt wastewater by low-temperature evaporation

ABSTRACT High-salinity wastewater, owing to its intricate composition and challenging treatment requirements, poses a significant hurdle in water environmental governance. In this study, low-temperature evaporation technology is used to tackle wastewater containing the volatile organic compound such as N,N-dimethylacetamide (DMAC). Utilisation of comprehensive approaches involving experimental testing, mathematical modelling, and Aspen Plus software simulations, The influence of DMAC on evaporation efficiency is researched through the following factors which encompassing its effects on boiling point elevation, partial molar activation energy, and the formation of by-products. Additionally, the comparation of the impact of temperature, ionic strength, intermolecular interactions on the evaporation rate and the concentration of the volatile component DMAC in the condensate is also conducted in this study. After conducting a multiple linear regression analysis of evaporation efficiency using the Statistical Product and Service Solutions (SPSS) tool, it was discovered that temperature serves as the primary determinant influencing the evaporation rate. Additionally, ionic strength impacts solution viscosity, intermolecular interactions, and saturated vapour pressure by altering the intermolecular forces, thereby indirectly influencing both the evaporation rate and the quality of condensate water. The comparative analysis of single-effect and double-effect evaporation indicates that the optimal operating condition for double-effect evaporation yields an evaporation rate of 70%, with a remarkable 88% reduction in steam consumption compared to single one. Based on heat and mass balance principles, the mathematical model for double-effect evaporation is established to offer crucial data support for practical industrial applications.

Second-Law Analysis of a Double-Effect Evaporator with Thermal Vapor Compression

In this paper, we present a steady-state analysis of a double-effect evaporator with thermal vapor compression (MED-TVC) installed in the Tunisian Chemical Group (GCT) factory. A thermodynamic model including mass and energy balances of the system is developed and integrated in a Matlab program. The model resolution yields to the determination of the operating parameters of the plant and the Gain Output Rate (GOR) was found to be roughly equal to 5. In a second step, the simulation results served to conduct a second law analysis of the unit. The performance criterion used in this analysis is the second law efficiency, i.e., the ratio of the least theoretical work of separation to the actual work input to the plant. The second law efficiency was found to be 2.4%. The distribution of the irreversibility between the different components of the plant was, in addition, assessed. As a conclusion, it was established that the most irreversibility occurs in the thermo-compressor which contributes with more than 50% to the global imperfection and which presents an exergy efficiency of less than 77%. The remaining irreversibility comes from the three exchangers (the two evaporators and the condenser) with an average contribution of 16%. As it is very difficult to introduce modifications into an existing unit, we assume that the importance of the results is not limited to the studied unit. They serve, rather, as an aid to the future design of a MED-TVC plant.

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.

Model Predictive Control of a Double Effect Evaporator Via Simulation

This paper is a study of the dynamic behavior of the double effect evaporator on the basis of energy and material balance under unsteady state conditions inside the evaporator. The simulation process was based on a model for the intensification of tomato juice. The mathematical model was used to study the effect of operational conditions, namely, the temperature of the feed, the flow rate of the feed, and the feed concentration. The dynamic behavior of the open system was studied by measuring the temperature response of the evaporators to the change of the staging function in the temperature of the feed, the feed flow rate and the feed concentration in the rate of (±10%, ±20%).The proportional-integral-derivative and model predictive controllers were applied to solve the difficult problem by determining the best operational conditions and avoid a sharp increase in temperature. Two methods are tested to control a wide range of operating conditions and simulation results show that there is good accuracy. The MPC controller is more accurate than the PID control and faster to reach the constant value.

Experimental study of a novel double-effect evaporation concentration system for high temperature heat pump

In order to solve the problem of energy saving of MVR and energy waste in MEE in the field of low vacuum and low temperature evaporation, a heat pump system and a double effect evaporation concentration system are combined to propose a high temperature heat pump double effect evaporation concentration system. It replaces the high-temperature steam heat source and makes full use of the heat of the last-effect secondary steam, and at the same time realizes the recycling of the intermediate water. In this paper, an industrial experimental platform is designed and built. The experimental results showed: the total evaporation of this system can reach 1985 kg/h, the heat pump COP is 4.92, the unit power consumption evaporation is 11.86 kg/(kW·h). Besides, the thermal characteristics and influencing factors of high-efficiency heat pump double-effect evaporation system are studied, which provides experimental basis and guidance for the practical engineering application, efficient design and optimization of such systems.

Investigation and Control of Tomato Production Plant

The demand for tomato paste is daily used over the year with the fact that it is abundant in certain seasons and scarce during other season. Many methods are used to preserve the juice or the paste through drying and with addition of preservative. Tomato grows under ambient conditions or in green houses at a temperature of 20°C - 27°C with high contents of vitamins A and B, potassium, iron, and phosphors. Tomato is a source of fiber; it doesn’t contain sodium salt, fats, or cholesterol; in fact it is the cheapest food of the poor common people. Tomato while waiting for processing to paste deteriorates rather quickly, and shall be thoroughly rinsed with sterilized clean water using rotary washers. The washed tomato is inspected, sorted, and chopped. The tomato liquor is processed through an extraction unit where the juice is separated away from outer skin, seeds and fibers. To avoid oxidation and foaming the tomato liquor is deaerated; the juice is deaerated by taking the vacuum as soon as it is formed. A double-effect evaporator is used to concentrate the tomato liquor under partial vacuum of 0.5 atmospheres; this is important to minimize heat damage, oxidation and dark color. The tomato paste is then sterilized with small amount of non-harmful preservatives and then canned, labeled and sent to store. To achieve the international standard specifications and metrology organization a control system is developed, tuned and analyzed for stability conditions. It is recommended that a tomato production plant has to be constructed in countries like Sudan and other countries with similar weather conditions.

Energy Saving Research on Multi-effect Evaporation Crystallization Process of Bittern Based on MVR and TVR Heat Pump Technology

This work keeps an eye on the energy saving research on evaporation crystallization process of bittern. Based on the thermo sensitivity of solubility of various salts in bittern, the magnesium salts are purified. The conventional evaporation crystallization process used to separate the bittern demands high energy consumption and has low thermodynamic efficiency. Therefore, the multi-effect evaporation (MEE), thermal vapor recompression (TVR) heat pump and mechanical vapor recompression (MVR) heat pump technology were applied to the conventional evaporation crystallization process. The MVR and TVR technology can both make full use of the secondary steam heating materials that will save energy. In addition, Aspen Plus (Version 7.3) was used to simulate the processes of the electrolyte-containing system under the ELECNTRAL thermodynamic model. For the better evaluation of various evaporation crystallization processes, some important evaluation indexes, such as energy consumption, annual total cost (ATC) and exergy loss were chosen as objective functions. Compared with the double-effect evaporation crystallization process coupled with TVR heat pump technology, the results indicated that the double-effect evaporation crystallization process coupled with MVR heat pump technology can save energy consumption and ATC by 80.52% and 15.32% respectively. Furthermore, the MVR heat pump technology takes the lowest effective energy loss, which is a more competitive factor of evaporation crystallization process of bittern.

Modeling of a double effect evaporator: Bond graph approach

This paper deals with the modeling of a chemical engineering system, which is the double effect evaporator (DEE). The main physical phenomenon encountered in this system is the heat transfer during distillation and concentration process. The modeling of DEE is carried out using bond graph approach. It allows description of interdisciplinary systems involving energetic, thermodynamic, hydraulic and thermal phenomena. In this study a dynamical models for the different parts of the DEE system are established. Simulation data are presented and confronted to the experimental results. To supervise the DEE system, the bond graph model is used to obtain analytical redundancy relations (ARR). They allow detection and isolation of faults.

Comprehensive exergy analysis of a commercial tomato paste plant with a double-effect evaporator

In this study, a detailed exergy evaluation of a commercial tomato paste plant with a double-effect evaporator was conducted in order to provide information on the system thermodynamic inefficiencies. Using energy and exergy balance equations, all components of the plant were analyzed individually and their exergetic parameters were calculated on the basis of actual operational data. The required data were obtained from Nazchin tomato paste factory located in Tehran, Iran. In addition, it was attempted to quantify the exergy utilized for processing a given amount of the tomato paste. The results showed that over 82% of the total destroyed exergy in the plant occurred in the boiler combination as the main component wasting exergy. Furthermore, exergy analysis introduced this combination as the main equipment rejecting exergy to the ambient where 4.79% of its total exergy input was lost. The rational exergy efficiency of the first- and second-effect evaporative units was found to be 65.33% and 56.60%, respectively. The specific exergy consumption of the tomato paste production was also determined as 16.83 MJ/kg. Generally, exergy concept and its extensions could be served as a powerful assessment technique to optimize the design and performance of multiple-effect evaporation systems employed in food industry.

Optimization of Multiple Effect Evaporators Designed for Fruit Juice Concentrate

The most important running cost item in evaporation is energy. However, energy consumption per unit production can be reduced considerably through the use of multi effect evaporation. A multiple effect evaporation scheme was studied and economically analyzed. Different economic items, including cost of steam and cost of evaporator in addition to annual total cost for single, double, three, four, five and six effects of evaporators were estimated and analyzed. The results indicated that minimum annual total cost is obtained by using a double effect evaporator.

An Efficient Measure for Quantification of Nonlinearity in Chemical Engineering Processes Based on I/O Steady-State Loci

Nonlinearity is virtually ubiquitous in chemical engineering plants, and assessing the degree of nonlinearity involved in a process is of special interest for process control purposes. In this paper, we introduce a simple nonlinearity measure to quantify the extent of nonlinearity in a dynamic system based on its normalized steady-state input/output loci. Our nonlinearity measure obviates the limitations of previous metrics in terms of computational effort and correct identification of highly nonlinear relationships. The measure is satisfactorily applicable to various I/O relationships—from truly linear to sinusoidal, for instance. In order to illustrate the efficiency of the proposed measure, four numerical examples concerning a double-effect evaporator, a jacketed continuously stirred tank reactor (CSTR) with an irreversible reaction, a CSTR involving van de Vusse reactions, and the Henson–Seborg–Pottmann CSTR are presented.

A single-product crystallization scheme

During the SIT conference in Dubai 2005 a single strike crystallization scheme model based on the way that Russian beet factory operated when refining raw sugar was proposed and suggested that it would be particularly suitable for medium size refineries up to about 2000 t/d RSO (refined sugar output). Now there is operational a 1700 t/d RSO stand-alone refinery that uses the scheme. It melts up to VHP raw sugar with 1200 IU (ICUMSA units) and runs carbonatation followed by a light dosing of PAC (powdered activated carbon) as necessary then double effect evaporation to produce fine liquor. Target color for the fine liquor is 340 IU. The centrifugal run-off needs to be segregated into the higher purity, lower color (so-called white) and lower purity, higher color (so called ‘green’) run-off. The white run-off (about 75%) is sent to white crystallization. The remaining 25% (green run-off) is sent to a three-stage crystallization recovery but, given the high purity regime without affination, the ‘A’ sugar is melted back to fine liquor having been crystallized and purged as if food quality. The results presented in the paper show that the refinery is operating broadly as predicted, producing a refined sugar to EEC 2 standard.

Simulation and Control of a Commercial Double Effect Evaporator: Tomato Juice

This work aims to present a detailed study on a commercial double-effect tomato paste evaporation system. The modeling equations formulated for process simulation belong to backward feeding arrangement. Open-loop process dynamics has been studied by rigorous simulation of the model structure. In the next, three multi-loop control schemes, namely conventional proportional integral (PI), gain-scheduled PI (GSPI) and nonlinear PI (NLPI), have been synthesized for the sample process. Finally, several simulation experiments have been conducted to investigate the comparative closed-loop performance based on set point tracking and disturbance rejection.

Model Building by Merging Submodels Using PLSR

PLSR (partial least squares regression) has become a basic tool for chemometrics, monitoring and modeling of processes, etc. The basic idea of PLSR is to relate two data matrices X and Y into a multivariate linear model, for analysis of the data with noisy and collinear variables. In industrial processes, sub-models of the specific units are built for monitoring and engineering process control. However, we know that these process units are not individually independent. As a result, the full model is usually desirable. In an actual process, there are thousands to ten thousands of variables being measured and conveniently recorded instantaneously. It is not practical to deal with such a large number of variables to construct a full model at time, especially they are collinear and embedded with noise. In this paper, the linear regression model merging procedure is proposed to incorporate PLSR models of subsystems into a full model. By way of this approach, the computation time and memory can thus significantly be reduced. It is quite suitable to merge the process sub-models built from PLSR into the complete one. The method could be extended to dynamic and non-linear modeling easily. Two examples for dynamic modeling and monitoring are presented for illustration. One is the dynamic modeling of a 4 x 4 linear process. Second one is the process monitoring of a double effect evaporator.

Heuristic-Based Mathematical Programming Framework for Control Structure Selection

This paper presents an optimization-based method for selecting manipulated variables for regulatory control schemes. The objective of this mathematical programming technique is the minimization of the overall interaction and sensitivity of the closed-loop system to disturbances. In addition, a general methodology for incorporating qualitative knowledge as linear constraints to the problem is demonstrated. The main advantage of the method is that the plantwide nature of the problem is preserved, because decisions related to different levels of the base regulatory control scheme are made simultaneously. The usefulness of the method is demonstrated using a double-effect evaporator case study, the hydrodealkylation of toluene case study, and the Tennessee Eastman challenge problem.

Generating operating procedures for chemical process plants

Operating procedure synthesis (OPS) has been used to generate plant operating procedures for chemical plants. However, the application of AI planning to this domain has been rarely considered, and when it has the scope of the system used has limited it to solving “toy” problems. This paper describes the application of state‐of‐the‐art AI planning techniques to the generation of operating procedures for chemical plant as part of the INT‐OP project at the Universities of Salford and Loughborough. The CEP planner is outlined and its application to a double effect evaporator test rig is discussed in detail. Particular attention is paid to the issues involved in domain modelling, requiring the description of the domain, development of AI planning operators, the definition of safety restrictions, and the definition of the problem. There is then a presentation of the results, lessons learned and problems still remaining.

On the regulation of a double effect evaporator: A trajectory planning and passivity approach

A dynamical feedback controller is proposed for the regulation of a simplified model of a double effect evaporator. The controller is based on feedback passivity considerations, complemented with a trajectory planning scheme in terms of the systems passive output. A drift vector field decomposition greately facilitates the direct application of the “energy shapping plus damping injection” feedback controller design methodology. The controller performance is enhanced with the aid of a trajectory planning scheme which effectively avoids singularity arcs in the state space, related to a loss of the relative degree of the passive output, while allowing for the satisfaction of physically meaningful state space and input space restrictions. The performance of the obtained controller design is evaluated by means of computer simulations

Robust performance of uncertain systems by output feedback

This paper considers a robust linear-quadratic (LQ) control problem for nominally linear systems with norm-bounded uncertainties. The uncertainties appear in all system matrices and do not satisfy matching conditions. A linear matrix inequality (LMI) approach is developed for constructing an output-feedback control law which guarantees the quadratic stability and an LQ performance level in the presence of uncertainties. The developed theory is illustrated on a double-effect evaporator model.

Sign and stability of equilibria in quasi-monotone positive nonlinear systems

The paper deals with the problem of finding the extension of a well-established connection between sign and stability of nontrivial equilibria in positive linear systems to the class of quasi-monotone positive nonlinear systems. The mathematical framework to provide the sufficient conditions guaranteeing such a relationship is the stability theory for nonlinear systems, especially the comparison principles and the method of vector Lyapunov functions. As an illustration of our results we present an example of a double-effect evaporator to study the sign-stability property of its only equilibrium point.