Sharif Digital Repository

Energy and environmental crises force different countries to consider new clean sources of energy, especially renewable energies. Fortunately, Iran is located on the solar belt and has a great potential to utilize this huge source of clean, sustainable, accessible and cheap energy. One of the applications of the solar energy is desalination of salty and polluted waters. In this regard, the performance of Multiple Active Solar Stills is investigated in this research. To do so, four similar samples of this device with one, two, three and four stages, were constructed on which many experiments were conducted for 24 hours periods. Experiments were conducted in both continuous (several days) and... 

Products on Research and Development (R&D) are followed by Technology development. Projects on R&D are cost intensive and considerable of financial resources should be allocated. Optimal allocation of resources could be managed through cost effective strategy. Hence, a “Model for planning and development of technology” has been developed in the present work, which lends itself to the analysis of the industrial application of planning of technological development based on minimizing costs of both development and application of a technology. Mixed Integer Programming optimization model has been developed which enables studying the structure of R&D activities. This model is based on the concept... 

Nowadays, water desalination is a widely-used method for producing clean and fresh water. Recent researches in this area have mostly focused on Reverse Osmosis technology which is one of the most efficient technologies in water desalination. A new idea to increase the efficiency of a recently-designed reverse osmosis membrane called “Honeycomb Carbon Nanotube Membrane” is presented through molecular dynamics simulation. Although in this study only the inlet area of the honeycomb structure which is a Y-shaped entrance, is modeled and studied, but obviously, any improvement in the membrane inlet, equals better results at outlet which means a more efficient desalination process. Present thesis... 

This research examines the produced water conditions in Iran and different ways of dealing with it; it looks forward to provide effective treatment system in order to confront the economic and environmental problems associated with the current operations and facilitate the exploitation of oil resources. Produced water in Iran have poor quality and high salinity, so the number of disposal options or use of it is very limited and non-industrial uses become non-economic and uncertain option. Seventy percent of Iranian oil reservoirs in onshore areas and reduced salinity concentration is a big challenge in produced water management. The first step in this project is finding an efficient and... 

This research aims to design and build a device that Using solar energy and can be used as water heaters and water desalination and water from the soluble hygroscopic. For this purpose, a combination of evacuated tube collector with parabolic through collector with sun tracking mechanism is used. sun tracking mechanism is polar and works with optical sensor. in this research we have designed new setup with evacuated tube collector for direct desalination and water heater. in this method heat pipes have been omitted from setup that cause high performance in heat transfer from evacuated tube collector to water and is minimized losses. 15w air compressor used to increased rate of evaporation ... 

Salt water is desalinated to produce fresh water suitable for human consumption or irrigation. Most of desalination methods require consuming large amounts of fossil fuels. Solar distillation is one of the best techniques from another available techniques for desalinating in small-scale brackish water. The main problem of these systems is the low rate of water production.Single basin solar still is a very simple solar device used for converting available brackish or waste water into potable water. This device can be fabricated easily with locally available materials. The maintenance is also cheap and no skilled labor is required. It can be a suitable solution to solve drinking water problem.... 

In recent years carbon nanotubes and other carbon nanostructures such as graphene sheets have attracted a lot of attention due to their unique mechanical, thermal and electrical properties. These structures can be used in desalination of sea water, removal of hazardous substances from water tanks, gases separation, and so on. The nano porous single layer graphene membranes are very efficient for desalinating water due to their very low thickness. In this study, the mechanism of passing water and salt ions through nano porous single-layer graphene membrane are simulated using classical molecular dynamics. In the simulation, in order to separate salt ions from the water, the effects of applied... 

One of the most significant problems of oil regions is salinity of the produced water extracted from the well. Penetrating the produced water through the surrounding environments of the oil well in recent years, plenty of environmental problems, especially agricultural ones have been caused in these areas. According to the increasing trend of water salinity during the time, one of the urgent action in the oil industry of the country should be finding a way to reduce the amount of dissolved salt in the produced water. The purpose to this project has been representing a more appropriate configuration for desalination of the produced water. Therefore, the water sample containing less than 70000... 

Microbial Fuel cells (MFCs) can be used to generate bioenergy in the form of electricity by using microorganisms and natural biological processes. The need for a supply of fresh water in many parts of the world has led to the innovation of modifying an MFC into a Microbial Desalination Cell (MDC) that adds the function of desalination to the MFCs existing ability to generate electricity directly from wastewater. The goals of this project were to design and analyze the use of a Microbial Desalination Cell (MDC) for the generation of electricity while simultaneously desalinating saline water and also to evaluate performance of bio-cathode in MFCs and MDCs. The newly designed MDC incorporates... 

The demand in water and energy for household, industrial and agricultural uses continue to grow. In recent years, many researches have been done on thermodynamic assessment and optimization of Combined Cooling, Heating and Power (CCHP) and desalination systems. The interesting and important point is the potential of combining CCHP and desalination systems by employing the solar power. The purpose of this study is exergy analysis and thermoeconomic optimization of a hybrid system of Multi-Effects Distillation desalination (MED) and CCHP, augmented by solar energy. The thermoeconomic analysis is carried out by Total Revenue Requirement (TRR) method. Properties of working fluid in hybrid MED... 

According to studies on solar stills, there has been designed an industrial solar still with a linear parabolic through collector (PTC) having higher efficiency than similar systems. Linear PTC coupled with heat pipe is very effective for increasing the efficiency of solar still. This system includes a parabolic trough collector functions by focusing the sunlight on a heat pipe and absorption of heat by a heat pipe. To minimize heat loss, heat pipe is embedded in an evacuated tube collector. By absorbing the heat, the working fluid of the heat pipe (ethanol) will be evaporated and due to its reduced density, it moves upwards and attains to the condenser. The external part of the condenser is... 

The mechanical spray evaporator (MSE) is a method of enhanced evaporation technology, normally designed to reduce the particle size of a wastewater droplet to volatilize water content of it as quickly as possible. A model of MSE has been built at the Institute of Water and Energy at Sharif University of technology. The aim of this research is to study the efficiency of enhanced evaporation technology for waste disposal. To achieve the accurate results, the required pumping rates and power consumption, sustained evaporation rates while operating the fans, and the performance during various temperature, wind speed and relative humidity, are required. Mechanical Spray Evaporator technique... 

Reverse osmosis (RO) is by far the most widely used membrane desalination process worldwide. The RO process depends on the properties of semi-permeable membranes which allow the separation of water from a salt solution by applying external pressure higher than the osmotic pressure on the seawater. The main problem in membrane separation process is the fouling of the membrane walls, which decreases the permeate flux. Having spacer filaments in the feed channel has been proven to dynamically change the concentration boundary layer and preventing fouling. The impact of spacer configurations (cavity, zigzag and submerged) on the alleviation of concentration polarization and the enhancement of... 

Sea water desalination needs fossil fuel and electricity. Although there has been major technical development in this case , including RO technical improvements, mainly motivated by oil exporting rich countries, under developed region still need investments for these processes. In this MSc project , a process using renewable energies is investigated to minimize operating costs. “Green technologies” for water desalination will become attractive with oil price increase. The green desalination process is simulated and sensitivity analysis of parameters is investigated. Based on the results, the optimum number of effect is 6, last effect pressure equal to 0.64 bar, and the sea water flow rate to... 

According to current researches, graphene oxide (GO) membranes show promising desalination properties due to ease of synthesis, low production cost, and high efficiency. There are several experimental works to study ionic sieving properties of GO membranes. However, it is difficult to characterize atomistic mechanism of water permeation and ion rejection by experimental approaches. On the other hand, there exist a few reports in which the atomistic picture of water permeation across GO membranes is investigated by means of molecular dynamics (MD) simulation. In the present work, in addition to water desalination, the atomic scale mechanism of ion rejection is studied using large scale MD... 

In the present study, for cost-effective brine elimination of desalination plants, a hybrid system consisting of a multiple-effect distillation unit and a humidification-dehumidification unit is proposed. The development process of the hybrid system was carried out in two main steps: 1) evaluation of electricity-driven and heat-driven humidification-dehumidification brine concentrators 2) redesigning the humidification-dehumidification unit according to the results of step one and hybridization the unit with a multiple-effect distillation system. All the steps are assessed using the energy, exergy, exergoeconomics, and exergoenvironmental tools.Among the three heat-driven and... 

The use of nanofluids for direct absorption of solar irradiance to produce freshwater has received much attention. Water-based nanofluids include metals, metal oxides, and nanocarbon-based fluids, which increase collector efficiency. On the other hand, the production cost of nanofluids is high, and when discharging the brine after the desalination process, these nanofluids cause environmental issues. Therefore, water-based organic colloids of coffee, walnut shell, black tea, and madder have been studied to overcome these problems. To accurately measure the behavior of colloids, laboratory single slope solar still was used in laboratory conditions. Also, two single slope solar stills with the... 

The forward osmosis (FO) process is a high potential emerging membrane process in the seawater desalination and contaminated water treatment fields. One of the main challenges facing this process is the weak separation (high reverse solute flux, low water flux, and insufficient selectivity) and antifouling performances of its membranes. Various sections of this study focus on the development of FO membranes and their performance improvement. For this purpose, thin-film composite membranes with the same combination of polyethersulfone/polyamide (PES/PA) have been used to investigate the effect of metal-organic frameworks (MOFs) introduction on their performance. The support layer in all cases... 

In this study, membrane distillation was used for desalination of high saline water. Recently, the synthesis of nanoparticles for the synthesis of membranes for membrane distillation has shown incredible improvement in the morphological properties, flux, and rejection. In this study, by incorporating UiO-66 functionalized with Palmitic acid into PVDF/PEG polymer solution we could improve membranes properties. Functionalization of UiO-66 with Palmitic acid was confirmed with FTIR, XRD, BET, SEM. In the membrane containing 3% Palmitic acid-UiO-66, the flux was increased by 46.5%, resulting in a flux of 12.6 LMH, and the salt rejection was improved from 99.5% to 99.9%. These results confirmed... 

Osmotically assisted reverse osmosis (OARO) assimilates high efficiency due to non-thermal processes and accessing high salinity. This makes it suitable for high water recovery for the purpose of zero- and minimal liquid discharge desalination. Moreover, forward osmosis (FO) has low fouling efficiency which makes the operating costs of cleaning and replacement lower. This study aims at incorporating OARO and FO in a novel configuration with multiple inlet of the diluted draw solution to the regeneration section. Pinch analysis with simplifying assumptions was carried out for FO and OARO standalone stages. The results showed that pinch point in FO resides either on the beginning or at the end...