Effect Distillation Research Articles

Nonlinear Multivariable Control of a Dividing Wall Column Using a Different-Factor Full-Form Model-Free Adaptive Controller

A dividing wall column (DWC), characterized by multivariable control, strong nonlinearity, and highly coupled systems, shows effective distillation capacity with a significant reduction in energy consumption and capital cost. Although multivariable control strategies for DWCs have attracted certain attention from both academia and industry, relatively little work has focused on data-driven multivariable controllers for such a complex system that is not easy to model. In this work, a novel different-factor full-form model-free adaptive controller (DF-FFMFAC) is first proposed for DWCs aiming to solve the problem of simultaneous control of the liquid level, column pressure, and temperature channels with quite different characteristics between them, which may be a challenging task for the prototype FFMFAC. Taking such complex dynamics into account, a parameter selection technique for the DF-FFMFAC based on neural networks is also developed, where gradient descent for the neural network is improved by the full-form dynamic linearization technique utilized in the DF-FFMFAC. Furthermore, the stability of the parameter tuning process is guaranteed by Lyapunov theory. The present work makes a noteworthy contribution to the multivariable control of DWCs in a purely online data-driven way without any offline training procedure and mathematical information. In terms of the separation of an ethanol–n-propanol–n-butanol DWC, the controller is cosimulated in MATLAB/SIMULINK and Aspen Plus Dynamics and tested against a series of feed flow rate and feed composition disturbances. As a result, the proposed method achieves encouraging control performance with smaller oscillations and faster responses compared with model predictive control and proportional–integral–derivative controllers, proving to be a promising data-driven method for the multivariable control of DWCs. Finally, the efficacy of the proposed scheme for the practical control of DWCs in the presence of measurement noise has also been demonstrated by adding white noise to the simulation.

MiDTD: A Simple and Effective Distillation Framework for Distantly Supervised Relation Extraction

Relation extraction (RE), an important information extraction task, faced the great challenge brought by limited annotation data. To this end, distant supervision was proposed to automatically label RE data, and thus largely increased the number of annotated instances. Unfortunately, lots of noise relation annotations brought by automatic labeling become a new obstacle. Some recent studies have shown that the teacher-student framework of knowledge distillation can alleviate the interference of noise relation annotations via label softening. Nevertheless, we find that they still suffer from two problems: propagation of inaccurate dark knowledge and constraint of a unified distillation temperature . In this article, we propose a simple and effective Multi-instance Dynamic Temperature Distillation (MiDTD) framework, which is model-agnostic and mainly involves two modules: multi-instance target fusion (MiTF) and dynamic temperature regulation (DTR). MiTF combines the teacher’s predictions for multiple sentences with the same entity pair to amend the inaccurate dark knowledge in each student’s target. DTR allocates alterable distillation temperatures to different training instances to enable the softness of most student’s targets to be regulated to a moderate range. In experiments, we construct three concrete MiDTD instantiations with BERT, PCNN, and BiLSTM-based RE models, and the distilled students significantly outperform their teachers and the state-of-the-art (SOTA) methods.

A multi-objective optimisation framework for MED-TVC seawater desalination process based on particle swarm optimisation

Owing to the high specific energy consumption associated with thermal desalination technologies such as Multi Effect Distillation (MED), there is a wide interest to develop a cost-effective desalination technology. This study focuses on improving the operational, economic, and environmental perspectives of hybrid MED-TVC (thermal vapour compression) process via optimisation. Application of particle swarm optimisation (PSO) in several engineering disciplines have been noted but its potential has not been exploited fully in desalination technologies especially MED-TVC in the past. A multi-objective non-linear optimisation framework based on PSO is constructed here. Two of our earlier models have been used to predict the key process performance and cost indicators. The models are embedded within the PSO optimisation algorithm to develop a new hybrid optimisation model which minimises the total freshwater production cost, total specific energy consumption and brine flow rate while maintaining a fixed freshwater production for a given number of effects and seawater conditions. The steam flow rate and temperature are considered as control variables of the optimisation problem to achieve the objective function. The PSO has successfully achieved the optimum indexes for the hybrid MED-TVC process for a wide range of number of effects. It also shows a maximum reduction of freshwater production cost by 36.5%, a maximum energy saving by 32.1% and a maximum reduction of brine flow rate by 38.3%, while maintaining the productivity of freshwater.

Measurement and correlation of the vapor-liquid equilibria related to the extraction of phenols from tar with mono-ethanolamine

Extracting phenol from coal tar has great economic significance. In this paper, a process for separating phenol from coal tar using mono-ethanolamine (MEA) as extractant was proposed, the conceptual design and optimized of the process was carried out by using Aspen Plus software. To ensure the accuracy of simulation, the vapor-liquid equilibrium data of MEA + phenol binary system were measured under different pressures. The binary interaction parameters of NRTL model, Wilson model and UNIQUAC model were fitted with the experimental data by data regression system. The results show that the deviation of NRTL model is less than that of Wilson model and UNIQUAC model. Considering that the boiling point difference between MEA and phenol is only 10°, two energy-saving schemes of double effect distillation are introduced into the conceptual process proposed in this paper, which can save 20% and 44.8% respectively compared with the traditional single tower distillation process. This paper provides reference for the industrial application of MEA in the extraction of phenol from coal tar.

Decreasing In Freshwater Production Due To Vacuum Pressure Decreasing On Multi Effect Distillation Installation


 
 
 
 A case study in a steam power plant has been conducted and reported. There was a case of decrease in the freshwater production rate in multi effect distillation installations that may disrupt the operation of the power plant. The cause was suspected by the drop in vacuum pressure in the evaporation chamber. The study was conducted by studying the MED installation process diagram and performing the theoretical calculations of energy and mass equilibrium in each chamber. To make it easier to find the properties of water in the energy calculation then add ins water_97 in Microsoft Excel is added.Calculations were undertaken in two modes, commissioning period and 2016 operation mode. The difference of the two modes was vacuum pressure level in each chamber. Vacuum pressure level in 2016 operation mode was lower than commissioning mode. The calculation at commissioning mode resulted in a production rate of 133.56 ton/h, while the actual condition at that time was 127 ton/h. Calculations in 2016 operation mode produced a theoretical fresh water production rate of 101.37 ton/h.
 
 
 

Techno-economic, environmental and emergy analysis and optimization of integrated solar parabolic trough collector and multi effect distillation systems with a combined cycle power plant

In this investigation, the improvement of the combined power plant that is located in Qom province was studied based on using solar energy and multi-effect desalination system. In this regard, energy, exergy, exergoeconomic, exergoenvironmental, emergoeconomic, emergoenvironmental as (6 E) analysis has been performed. Also, multi -objective genetic algorithm (MOGA) was applied to optimization of the propose cycle in view of 6 E analysis. Due to the high complexity of the optimization problem and reduce the computation time, the combination of genetic programing and artificial neural network has been employed to generate exact correlation for objective functions. The initial results demonstrated that adding the solar-based-thermal system caused an improvement of about 1.91% in the exergetic efficiency of the base plant. Moreover, by simultaneous integration of solar unit and desalination system in the base plant, the new-designed plant could generate 33 kg/s freshwater. It was determined from optimization results that the exergetic efficiency of the proposed plant increased by 3.22%. Furthermore, after optimization and at the optimum operating condition, power generation costs, power generation's environmental impacts, freshwater generation's costs, freshwater production's environmental impacts, and the emergy of the proposed system decreased about 6.27%, 24.51%, 36.51%, 26.13%, and 1.87%, respectively.

Pilot testing of a novel integrated Multi Effect Distillation - Absorber compressor (MED-AB) technology for high performance seawater desalination

This work presents a novel integration of Multi Effect Distillation with Absorption compressor (MED-AB) to reduce the energy consumption and unit water cost. The MED-AB pilot plant has been installed with a nominal capacity of 25 m3/day to validate the concept under a seawater salinity of 57,500 ppm (West of Qatar). Both pilot testing and the simulation results confirm the features of the novel design of the MED-AB process. Simulation of a commercial evaporator of 15 MIGD capacity showed that the specific energy consumption of the proposed MED-AB is calculated as 4.8 kWh/m3, which is 60% lower than the existing MED-TVC plant (13 kWh/m3). Compared to the traditional MED-TVC, the seawater feed and pumping power of MED-AB process is lower by 70% and 55%, respectively. The results confirm the minimization of the environmental impact of dumping thermal energy back into the sea and reduce the plant's capital investment, covering feed pumps size and the intake/outfall civil work. The levelized unit water cost of the MED-AB is calculated as 0.46 $/m3, which is 22% lower than that of a conventional MED-TVC desalination plant. The novel MED-AB technology would create a potential solution for the industrial applications of high salinity byproduct and solar desalination.

Pilot testing of a novel Multi Effect Distillation (MED) technology for seawater desalination

This work presents an improved evaporator design of the Multi Effect Distillation (MED) to minimize the thermal losses and footprint of the evaporator. An advanced modular MED pilot plant has been installed with a nominal capacity of 25 m3/day to validate the concept under a seawater salinity of 57,500 ppm (Dukhan Coast, West of Qatar), at the top brine temperature of 65 °C. Both the pilot testing and the simulation results confirm the features of the novel design of the MED. By implementing this invention's design, the heat transfer area has been decreased and accordingly, the capital cost of the evaporator is reduced by 20%. The tube arrangement with new vapor route allows the removal of the traditional demister, which accordingly reduces the footprint of the desalination plant by 65%. The sieve tray for spraying the seawater over the rectangular and inline tube bundle creates a uniform wettability. The improved design also discloses the utilization of an online vent water-ejector, for vent out of the non-condensable gases (NCGs). The novel evaporator design based low temperature MED technology, shows a potential solution for the industrial applications of high salinity byproduct and solar desalination.

Fresh Water Generator: A Review

This search presents a study for some types of fresh water generators FWGs, giving an overview of each type and comparing them with other types, and knowing the design criteria for different designs, as well as studying their advantages and disadvantages, including thermal desalting which types are vapor compression (VC), multi stage flash distillation (MSF), multiple effect distillation (MED), and multiple effecte evaporator, adsorption desalination, membrane distillation (MD), freezing desalination, and hydrate desalination. Then we studied the non-thermal desalination process, which includes electro-dialysis (ED), ion exchange desalination (IX), extraction desalination process, and additional types of fresh water generators FWGs.

Development and tri-objective exergoeconomic-environmental optimization of a novel molten carbonate fuel cell-based system for power, hydrogen and freshwater tri-generation

The world power sector is going to change over from its conventional large scale power systems to novel small scale efficient ones, where the fuel cell technology is a promising option. In this paper, a novel tri-generation system based on MCFC is presented for power, hydrogen and freshwater production. The Solid Oxide Electrolyzer Cell (SOEC) is employed for hydrogen production and Multiple Effect Distillation (MED) system is used for freshwater generation to recover the MCFC waste heat. Comprehensive exergoeconomic evaluation and tri-objective optimization is conducted considering exergy efficiency, product cost and CO2 emission as the objectives. Besides the operating conditions and optimal design variables are determined for single-objective optimizations. The results show that, tri-generation system yields at least 4.5% gain in exergetic efficiency compared to the standalone MCFC. From the parametric study it is revealed that, higher values of hydrogen production is reached for lower fuel utilization factor and stack temperature and higher current densities. Meanwhile, higher values of freshwater is attained with higher steam to carbon ratio, fuel utilization factor, stack temperature, and lower current density values. The tri-objective optimization results demonstrated that the minimum cost and emissions can be reached to 9.37 $/GJ, and 1.425 ton/MWh, respectively while the maximum efficiency is 46.54% at the best point.

Impact of phosphonium-based ionic liquid on the corrosion control of aluminum alloy AA5052 in MED desalination plants during acid cleaning process

Aluminum alloy AA5052 has recently been chosen to replace titanium tubes in desalination plants' multiple effect distillation (MED) units. The high corrosion rate of AA5052 during the acid cleaning process to remove the scale layer, on the other hand, remains a significant challenge. In this paper, we describe for the first time the use of an ionic liquid, tributyl(ethyl)phosphonium diethyl phosphate (Ph-IL), as a corrosion inhibitor for aluminum alloy AA5052 during the acid cleaning process with a 4% sulfamic acid solution. Remarkably, the addition of ionic liquid Ph-IL to sulfamic acid results in enhanced corrosion resistance of AA5052 with the efficiency reached to 93.0%. Through the adsorption of both the cationic and anionic parts of the ionic liquid, Ph-IL molecules can cover the anodic and cathodic sites. Furthermore, the Ph-IL forms a significant activation energy barrier against the corrosion process. In addition, SEM-EDX analysis confirms the formation of protective layers of Ph-IL molecules on the surface of AA5052. This finding may be helped in the expansion of the use of many ionic liquids with their new properties in the field of desalination.

Minimisation of energy consumption via optimisation of a simple hybrid system of multi effect distillation and permeate reprocessing reverse osmosis processes for seawater desalination

Multi Effect Distillation (MED) and Reverse Osmosis (RO) processes have been extensively used to produce freshwater from seawater resources. amongst many performance indicators, energy consumption of different configuration of hybrid system of MED and RO processes have been analysed in the past. Hybrid MED-RO system is energy intensive and use of fossil fuel can significantly increase the carbon footprint, unless stable renewable energy sources are used. In this work specific energy consumption of a simple hybrid MED-RO system with permeate reprocessing is minimised while optimising a number of operating decision variables using model based optimisation technique. A detailed process model developed earlier by the authors is embedded in the optimisation framework resulting in a constrained Non-linear Programming (NLP) problem. The minimum specific energy consumption achieved in this work is about 18% lower than what is reported in the literature resulting in a significant energy saving and thus carbon footprint.

Commercial Thermal Technologies for Desalination of Water from Renewable Energies: A State of the Art Review

Thermal desalination is yet a reliable technology in the treatment of brackish water and seawater; however, its demanding high energy requirements have lagged it compared to other non-thermal technologies such as reverse osmosis. This review provides an outline of the development and trends of the three most commercially used thermal or phase change technologies worldwide: Multi Effect Distillation (MED), Multi Stage Flash (MSF), and Vapor Compression Distillation (VCD). First, state of water stress suffered by regions with little fresh water availability and existing desalination technologies that could become an alternative solution are shown. The most recent studies published for each commercial thermal technology are presented, focusing on optimizing the desalination process, improving efficiencies, and reducing energy demands. Then, an overview of the use of renewable energy and its potential for integration into both commercial and non-commercial desalination systems is shown. Finally, research trends and their orientation towards hybridization of technologies and use of renewable energies as a relevant alternative to the current problems of brackish water desalination are discussed. This reflective and updated review will help researchers to have a detailed state of the art of the subject and to have a starting point for their research, since current advances and trends on thermal desalination are shown.

The impact of vapor box location on the performance of the multiple effect distillation for seawater desalination technology

The impact of vapor box location on the performance of the multiple effect distillation for seawater desalination technology

Study of a modified multiple effect distillation (MED) brackish water system for a minimal water footprint

Study of a modified multiple effect distillation (MED) brackish water system for a minimal water footprint

Learning From Images: A Distillation Learning Framework for Event Cameras.

Event cameras have recently drawn massive attention in the computer vision community because of their low power consumption and high response speed. These cameras produce sparse and non-uniform spatiotemporal representations of a scene. These characteristics of representations make it difficult for event-based models to extract discriminative cues (such as textures and geometric relationships). Consequently, event-based methods usually perform poorly compared to their conventional image counterparts. Considering that traditional images and event signals share considerable visual information, this paper aims to improve the feature extraction ability of event-based models by using knowledge distilled from the image domain to additionally provide explicit feature-level supervision for the learning of event data. Specifically, we propose a simple yet effective distillation learning framework, including multi-level customized knowledge distillation constraints. Our framework can significantly boost the feature extraction process for event data and is applicable to various downstream tasks. We evaluate our framework on high-level and low-level tasks, i.e., object classification and optical flow prediction. Experimental results show that our framework can effectively improve the performance of event-based models on both tasks by a large margin. Furthermore, we present a 10K dataset (CEP-DVS) for event-based object classification. This dataset consists of samples recorded under random motion trajectories that can better evaluate the motion robustness of the event-based model and is compatible with multi-modality vision tasks.

Influence of Nickel oxide nanoparticles on the absorption enhancement of solar radiation for effective distillation by single slope wick-type solar still

Abstract This paper presents the productivity enhancement of a single slope wick-type solar still by the addition of Nickel oxide nanoparticles prepared from stem and leaf extract of Acalypha Indica in the saline water of the water reservoir of the still. Concentration of 0.12% Nickel oxide nanoparticles for 50 kg of saline water is found to be optimum to enhance the productivity. The proposed still has produced total distillate yield of 5.8 l/m2day (NiO nanoparticles from Stem extract), 5.75 l/m2day (NiO nanoparticles from leaf) and 4.2 l/m2day over 24 h cycle with and without nanoparticles over 24 h cycle in the local climatic condition of Coimbatore, Tamilnadu, India. The productivity is increased due to the increased absorption of solar radiation by the Nickel oxide nanoparticles and utilization of absorbed thermal energy during night-time for distillation. This is due to the convection of absorbed thermal energy to the saline water in the reservoir.

Performance analysis and optimization of hybrid multi-effect distillation adsorption desalination system powered with solar thermal energy for high salinity sea water

Performance analysis, parametric study and response surface methodology (RSM) based optimization of hybrid Multi-Effect Distillation Adsorption Desalination (MEDAD) system powered with solar energy is presented in this paper. The goal is to develop innovative and cost-effective technology for high salt concentration sea water desalination using renewable energy technologies. The main objectives are to develop sustainable methods and strategies to enhance the quality and quantity of freshwater production; and reduce the energy consumption during the desalination process. The effect of number of stages for the Multi Effect Distillation (MED) system, the addition of the adsorption desalination (AD) stage and the heat recovery from the residual brines on the performance of the MEDAD system for high salinity sea water under hot and humid climatic conditions are investigated. The analytical analysis and an optimization method are used in this study to determine the system’s optimum operating conditions to maximize the freshwater production, reduce the energy consumption and performance ratio. Four input factors are selected for the parametric study: Heat transfer fluid temperature and Reynolds number; and sea water temperature and total dissolved solids TDS. The results show that the production rate of fresh water was improved by 2.68 times, achieving a 57.78% lower specific energy consumption by adding the adsorption desalination stage. For the heat recovery from the residual brine, the results show that the freshwater production rate and the performance ratio increased by respectively 14.73% and 12.86%, and the specific energy consumption decreased by 11.34%. New correlations for the variation of the inverse of the specific energy consumption (m3/kWh) and the performance ratio versus the four input factors and the order of importance of the input factors are presented.

Expansion and scale up of technology for ethanol production based on the concept of biorefinery

AbstractThe rapid growth of industries and large number of population are considered to be the major two factors that contribute to the crisis of global energy. Biofuels are considered to be the best replacement of the energy produced from the nonrenewable fossil fuels. The use of mature technologies depicts a sear need of biomasses that it causes a competition with the food chain in case of the first generation of Bioethanol. This disadvantage was overcome by the second generation bioethanol where lignocellulosic biomass is the raw material. Algal biomass from marine environment has also gained a lot of importance in third and fourth generation of raw material for biofuel production. The main challenge arrived when scaling up became the biggest problem in the process of bioethanol production. This review mainly aims to focus on the challenges faced in the commercialization of the biofuels. Many scientists are working majorly on economic processes so as to commercialize the biofuel production techniques. Some energy and cost effective distillation process has been described in this review article, which can help in the scaling up the process to an industrial level.Practical ApplicationsThis review mainly aims to focus on the basic overview of the bioethanol production and the challenges faced in the commercialization of the biofuels. Many scientists around the globe are working majorly on economic processes so as to commercialize the biofuel production techniques. The review compiles the evolution of one generation biofuels from another by overcoming the disadvantages of the previous generation. This will help the young researchers to have a complete idea about significance of bioethanol production. In the present times, there are many less pollution causing and renewable natural resources that can produce bioethanol in the laboratory scale effectively. The main challenge is to produce bioethanol in large scale. Though this area for scale up technologies of the ethanol production is less explored, but there is immense scope of development and modification.

Metrics Matter: Accurately Defining Energy Efficiency in Desalination

Abstract Energy cost contributes a large portion of the overall cost of desalinated water. Improving the energy efficiency of desalination plants is therefore a primary design goal. However, accurately evaluating and comparing the energy consumption of desalination plants that use different forms and grades of energy is difficult, especially for power–water coproduction systems in which primary energy (PE) consumption leads to both salable electricity and potable water. The power plant converts PE into grades of thermal energy and electricity usable by the desalination plant. To fully capture the thermodynamic and economic cost of energy, and to fairly compare desalination systems that use different grades of input energy, we must compare energy consumption not at the point where energy enters the desalination plant itself, but as PE consumption entering the power plant. This paper investigates a variety of metrics for comparing the energy and exergy consumption attributable to desalination in coproduction plants. Previous results have shown that reverse osmosis (RO) is approximately twice as efficient as multiple effect distillation (MED) on a PE basis. We then compare the PE consumption of MED and RO from a thermoeconomic perspective. The entropy generation at the RO membrane and in the MED effects are derived in similar terms, which enables a comparison of the overall heat transfer coefficient in an MED system to the permeability of an RO membrane. RO outperforms MED in energy efficiency because of a balance of material costs, transport coefficients, and cost of energy.