A standard primary energy approach for comparing desalination processes

For future sustainable seawater desalination, the importance of achieving better energy efficiency of the existing 19,500 commercial-scale desalination plants cannot be over emphasized. The major concern of the desalination industry is the inadequate approach to energy efficiency evaluation of diverse seawater desalination processes by omitting the grade of energy supplied. These conventional approaches would suffice if the efficacy comparison were to be conducted for the same energy input processes. The misconception of considering all derived energies as equivalent in the desalination industry has severe economic and environmental consequences. In the realms of the energy and desalination system planners, serious judgmental errors in the process selection of green installations are made unconsciously as the efficacy data are either flawed or inaccurate. Inferior efficacy technologies’ implementation decisions were observed in many water-stressed countries that can burden a country’s economy immediately with higher unit energy cost as well as cause more undesirable environmental effects on the surroundings. In this article, a standard primary energy-based thermodynamic framework is presented that addresses energy efficacy fairly and accurately. It shows clearly that a thermally driven process consumes 2.5–3% of standard primary energy (SPE) when combined with power plants. A standard universal performance ratio-based evaluation method has been proposed that showed all desalination processes performance varies from 10–14% of the thermodynamic limit. To achieve 2030 sustainability goals, innovative processes are required to meet 25–30% of the thermodynamic limit.

Desalination processes evaluation at common platform: A universal performance ratio (UPR) method

Renewable energy systems for water desalination applications: A comprehensive review

Sustainable desalination using ocean thermocline energy

Desalination has been growing rapidly as an industry and as a field of research that combines engineering and science to develop innovative and economical means for water desalting. Many countries in the world, especially in the Middle East, depend heavily on seawater desalination as a major source of drinking water and have invested considerable efforts and financial resources in desalination research and training. Desalination plants have seen considerable expansion during the past decade as the need for potable water increases with population growth. It is estimated that the world production of desalination water exceeds 30 million cubic meters per day and the desalination market worldwide is expected to reach $ 30 billion by 2015. One of the major economical and environmental challenges to the desalination industry, especially in those countries that depend on desalination for potable water, is the handling of reject brine, which is the highly concentrated waste by-product of the desalination process. It is estimated that for every 1 m3 of desalinated water, an equivalent amount is generated as reject brine. The common practice in dealing with these huge amounts of brine is to discharge it back into the sea, where it could result, in the long run, in detrimental effects on the aquatic life as well as the quality of the seawater available for desalination in the area. Although technological advances have resulted in the development of new and highly efficient desalination processes, little improvements have been reported in the management and handling of the major by-product waste of most desalination plants, namely reject brine. The disposal or management of desalination brine (concentrate) represents major environmental challenges to most plants, and it is becoming more costly. In spite of the scale of this economical and environmental problem, the options for brine management for inland plants have been rather limited. These options include: discharge to surface water or wastewater treatment plants; deep well injection; land disposal; evaporation ponds; and mechanical/thermal evaporation. Reject brine contains variable concentrations of different chemicals such as anti-scale additives and inorganic salts that could have negative impacts on soil and groundwater. This chapter highlights the main concerns as well as the environmental and economical challenges associated with the generation of large amounts of reject brine as a by-product of the desalination process. The chapter also outlines and compares the most common options for the treatment or disposal of reject brine. The chapter focuses on a novel approach to the management of reject brine that involves chemical reactions with carbon dioxide in the

Numerous studies have been undertaken since the start of the 1990s—when various authors began to propose the use of artificial intelligence in the field of water desalination—on the employment of computational intelligence (CI) systems in this technological field. The main goal of the proposals put forward has been to tackle the high degree of complexity involved in the different processes that can be found in the desalination industry. The wide variety of topics suggested as potential candidates for the application of CI in desalination processes include, among others, alarm processing and fault detection, control systems, operational optimization applications, load forecasting and security assessment. Although desalination plants have traditionally been powered by energy supplied by the burning of fossil fuels, there is a growing trend today, for various reasons, to use renewable energy sources to directly power these plants. This has added new challenges to the management of desalination processes as the temporal variability of renewable energy sources makes the decision-making processes more complicated. In turn, this means that a multivariable approach is required to ensure optimal desalination plant operation by maximizing the exploitability of the variable renewable resource. This chapter presents a review of how CI systems have been used to date in the desalination industry. A special mention is given to new developments which use CI systems to help overcome newly emerging challenges related to the increasing usage of renewable energy sources in the powering of desalination processes.

The balancing act between neutral accounting policies and accounting policies that take economic consequences into consideration has been on the agenda of accounting regulators and researchers since the 70s. The transition to fair value accounting in conjunction with the recent economic crisis have led to a revival of interest in this balancing act especially in the field of pension accounting. Due to the negative economic consequences anticipated by companies sponsoring defined benefit pension funds (e.g., decrease in owners’ equity), pension accounting has moved from an accounting that takes into consideration economic consequences to a more neutral accounting only gradually and not in a once-and-for-all event. This paper documents identified and anticipated economic consequences of recent pension accounting changes like shifts between different types of pension plans (from defined benefit to defined contribution), changes in the governance structure between the sponsoring organization and the pension fund (less accountability by pension fund), more incentives for earnings management, and changes in investments strategies by sponsoring organizations (from equity to bonds). Recent proposals for regulatory changes (i.e., IAS 19 revised) head towards an excessive conservatism and hence diminished neutrality. During and in the aftermath of the recent economic crisis – when interest rates are low – conservative pension accounting can have negative economic consequences if pension funds look as if they are underfunded and sponsoring companies present higher retirement related expenses. Shifts in the accounting policies that depart from neutrality and have negative economic consequences should be taken into consideration by regulators when issuing accounting standards.

A multi evaporator desalination system operated with thermocline energy for future sustainability

Demystifying integrated power and desalination processes evaluation based on standard primary energy approach

Stainless steels and desalination industry is a long story centered on life-cycle cost principle. Indeed, their use and development affected the choice of designers and plant end-users. Although, many learned lessons have been acquired on the performance of these ferrous materials, each stainless steel grade has a defined role and record within the desalination process. Depending on process conditions and equipment design, the involvement of mechanical stresses induces what is called “Environmental Assisted Cracking” for some susceptible stainless steel grades. In the present chapter, we will discuss the pre-requisite and practical solutions for this type of damage and the concerned alloys with available case studies covering static and rotating equipment.

Dynamic simulation of once-through multistage flash (MSF-OT) desalination process: Effect of seawater temperature on the fouling mechanism in the heat exchangers

Distillation has been a very important separation technique used over many centuries. This technique is diverse and applicable in different fields and for different substances. Distillation is important in the desalination section. Various principles are used in desalting seawater and brackish water to fulfill the demands of freshwater. This work explains the modes and principles of distillation in desalination, their types, present improvement, challenges, and limitations as well as possible future improvements. The first and primary mode of distillation is the passive type. As times went by and the demand for freshwater kept increasing, other modes were introduced and these modes fall under the active distillation type. However, each mode has its own advantages, disadvantages, and limitations over each other. The principles and modes of distillation are as significant as understanding the energy sources needed for distillation. Hence, they are the basic knowledge needed for future innovation in the desalination industries.

Concern for the environment and the need to conserve water are forcing change in the desalination industry. Users of brackish water desalination equipment are demanding minimum waste to conserve raw water supplies and recovery of wastewaters for industrial reuse by desalination processes is becoming common. Electrodialysis is meeting these challenges with improved membranes that have high efficiency, substantial resistance to oxidants and extreme resistance to organic fouling. These recent developments have led to the successful application of electrodialysis technology to demineralize cooling tower, refinery and other wastewaters as well as potable supplies at high water recoveries.

With the increasing demand for freshwater for drinking, industrial, and agricultural purposes, desalination of seawater is a significant solution. Freezing desalination is a less costly process compared to other thermal methods; thus, it can be a proper alternative choice in the desalination industry. Numerical simulation of this process is advantageous in the design and optimization of this technology. The modeling of this process with common computational fluid dynamics methods is computationally expensive due to the small time scale of freezing. In this study, we develop a lattice Boltzmann method to solve the momentum and energy equations. This method is coupled with the finite difference discretization of species transport equation for the concentration of salt. A two-dimensional cavity filled with 35 g/L saltwater with one cold surface is investigated. The desalination process at three different times is analyzed. Also, the effect of changing the position of the cold wall in the presence of gravity is examined. The left and top surface cooling presents higher desalination efficiency as the purification efficiency is twice as the bottom surface cooling in terms of brine salt concentration. It was also found that reducing the temperature of the cold wall can have a more significant effect on desalination efficiency rather than changing the position of the cooling surface. The brine concentration obtained from the top cooling surface after 30 min at 250 K was 7.803%, while that of the bottom surface cooling after 10 min at 230 K was 8.40%.

All at <b>Sea?</b>