High-pressure Brine Research Articles

Multi-objective optimization and energy efficiency improvement for rotor duct in integrated energy recovery-pressure boost device

To reduce the volumetric mixing rate of the integrated energy recovery-pressure boost device, a novel symmetrical duct structure with diversion surface was proposed. The surrogate model-based multi-objective optimization framework was established, and obtained the optimal ducts V1 and V2 combined with computational fluid dynamics simulation. Numerical results indicate that optimized duct structure could promote the formation of plug flow and effectively improve the collision efficiency between high-pressure brine and low-pressure seawater, and the volumetric mixing rate corresponding to the ducts V1 and V2 was reduced by 31.52% and 22.18%, and the duct volume efficiency was increased by 16.04% and 19.56%, respectively. Finally, the performance of optimized device was verified through seawater reverse osmosis desalination system under actual working conditions. Experimental results showed that the mixing rate of optimized ducts had a significant decrease of 30.86% and 20.53% in the applicable range, and the energy recovery efficiency improved at most 5.41% and 7.55%, respectively. The optimized ducts could significantly reduce the specific energy consumption of the desalination system by 26.01% and 18.22%, respectively, and the specific energy consumption reached the lowest level of 3.02 kWh/m3, demonstrating the superiority of the structure and the accuracy and effectiveness of the optimization strategy.

Numerical study on the energy consumption characteristics of a novel integrated pump-motor unit for SWRO desalination system

Energy recovery device (ERD) is a critical component in seawater reverse osmosis (SWRO) desalination systems, which recovers hydraulic energy from the high-pressure brine and effectively reduces system energy consumption. In this thesis, a novel integrated seawater desalination pump-motor energy recovery device (ISPM-ERD) without the slipper/swashplate interface is proposed to further reduce energy consumption and improve system integration, which is able of concomitantly achieving seawater pressurization and energy recovery. A co-simulation multibody dynamic model with rigid-flexible coupling is applied to precisely examine the internal power loss of ISPM-ERD, especially volumetric loss and mechanical loss of the key lubricating interface. Besides, the influence of shaft rotational speed and working pressure on the power loss and overall efficiency of ISPM-ERD are comparatively investigated. In addition, a performance study of the presented ISPM-ERD is carried out based on the co-simulation model, which reveals the energy recovery efficiency and specific energy consumption (SEC) of ISPM-ERD under various operating conditions. The results indicate that the proposed ISPM-ERD is sufficient to meet the needs of the small-scale SWRO systems, whose energy recovery efficiency is more than 90.1 % in the 3.0–7.0 MPa operating pressure range and the SEC of freshwater production is 2.94 kW·h/m3 under rated working conditions.

Treatment of ultra high-pressure brine overflow by drainage brine with controlling pressure technology

Overflow of high -pressure brine causes stratification and sedimentation of drilling fluid, which damages the performance of drilling fluid and lead to serious accidents such as sticking. In the face of saltwater overflow, the common practice is to increase the density of drilling fluid to prevent and deal with it. However, increasing the density will lead to serious lost circulation in the thief layer, thus aggravating the saltwater overflow. In order to solve this problem, this paper puts forward a method of drainage brine with controlling pressure to deal with the overflow of high -pressure brine layer. Through laboratory experiments, the pollution capacity limit of high -pressure brine on oil-based drilling fluid was determined, and the drainage brine with controlling pressure technology was systematically proposed. The controlled pressure water drainage treatment technology has been successful applied in 4 Wells drilling in ultra- deep salt paste formation in Tarim Basin.

Path toward sustainable desalination: Sodium precipitation and carbon capture

Current desalination technologies are not sustainably scalable due to high operational costs, high carbon emissions, and the environmental impact of brine. Almost all desalination plants built today use Reverse Osmosis technology, with research primarily focused on developing ultra-high permeability membranes that lower specific energy consumed. We believe sustainable desalination can be achieved by optimizing the overall Reverse Osmosis system. Our method takes advantage of the high-pressure brine, high levels of total dissolved solids, and the sheer amount of brine waste discarded. This is achieved by bubbling CO2 into ammoniated brine to precipitate sodium ions. The process was studied by modeling CO2 absorption, simulating real brine behavior, and optimizing for sodium removal. The results showed that ammonia requires 528 kg of CO2 per cubic meter of freshwater. In addition, the results revealed that CO2 absorption at 22.2 °C and 68.7 bar removed 72.5 % of the dissolved sodium. Ammonia unlocks the path toward sustainable desalination, as it can be absorbed and regenerated within the reverse osmosis system.

The void fraction and frictional pressure drop of upward two-phase flow under high pressure brine condition

The offshore methane hydrate production test conducted in Japan has demonstrated a successful production of methane gas from marine gas hydrates using depressurization methods. The method produces methane gas by dissociating methane hydrate, which is stable at low temperature and high pressure conditions, by lowering the bottom-hole pressure in the wellbore. Under this method, stable control of bottom-hole pressure is necessary to ensure continuous methane gas production. Therefore, understanding the behavior of upward gas–liquid two-phase flow, involving gas-brine mixture, in a wellbore is essential for the proper pressure drop evaluation in the production line. In the present study, void fraction and frictional pressure drop behaviors under nitrogen-brine two-phase flow conditions is investigated using the high-pressure test facility of 52.7 mm inner diameter and 28 m height. The measured void fraction was assessed using drift-flux model, and the results showed that the decrease in bubble diameter under bubbly flow in gas-brine two-phase flow conditions resulted in decrease in bubble rise velocity and uniformity of bubble distribution. It was also found that, under bubbly flow in gas-brine mixture, the frictional pressure drop tends to further decrease with elevation. Based on these findings and obtained experimental dataset, the new frictional pressure model for gas-brine two-phase flow under high-pressure conditions is developed in the present study.

Feasibility analysis of a thermo-hydraulic process for reverse osmosis desalination: Experimental approach

Reverse osmosis is a widely used desalination technique, mainly because of its low specific energy consumption. Autonomous reverse osmosis processes are increasingly developed because of their energy efficiency and the decentralization of numerous water stress areas. In this context, a reverse osmosis process powered by an innovative thermo-hydraulic desalination system using heat has been developed. This new process aims to autonomously produce fresh water from a brackish water source, compatible with the needs of a small remote village. This new reverse osmosis desalination process exploits a low temperature heat source (60–80 °C) such as the one delivered by solar flat-plate collectors. The heat is then converted into hydraulic energy by a thermodynamic engine cycle in which the expansion of the working fluid directly pressurizes the brackish water by means of hydro-pneumatic tanks, while energy from high pressure brine is recovered by an innovative hydraulic cylinder. Since previous numerical work on this process shown a specific energy consumption about 12 kWh m−3 for a 4 g L−1 brackish water, which is close to performances of relatable processes, an experimental full scale prototype has been built. The work presented here shows the results of the experiments conducted on this prototype, its behavior and performances. Numerical and experimental results are compared and discussed, and confirm the feasibility of the process. These tests show a promising cyclic functioning as the numerical results suggested. The freshwater production and salinity is remaining under the drinkability limit and the experimental specific energy consumption has been calculated to 25 kWh m−3. In order to reach better performances, transfer tanks needs to be improved to avoid heat transfer between working fluid and saltwater which leads to condensation issues, and another hydraulic cylinder design needs to be consider to avoid gasket abrasion.

Development and fluid fluctuation analysis of a novel valve-controlled energy recovery device for small-scale reverse osmosis desalination systems

Energy recovery devices (ERD) are vital for improving the energy efficiency of reverse osmosis (RO). Nevertheless, small-scale seawater RO systems are rarely equipped with ERDs, mainly because of the associated high capital and maintenance costs. Herein, we propose a new type of reciprocating switcher (RS)-ERD with dual self-boost hydraulic cylinders that can pre-pressurize the low-pressure hydraulic cylinder during stroke switching. The structure and working process of the pre-pressurization reciprocating switcher (PPRS)-ERD are presented, and mathematical models of the entire system are established. Based on these models, a detailed performance analysis is performed. Compared to the conventional RS-ERD, both the high pressure (HP) check valve cores and hydraulic cylinders move smoothly, which suggests that the vibrations of the check valves and cylinders can be neglected. The maximum pressure fluctuation amplitudes of HP seawater (HPS) at the outlet and HP brine (HPB) at the inlet are 0.015 MPa and 0.016 MPa, which represent decreases of 98.91 % and 98.87 %, respectively. The flow fluctuation amplitudes of HPS and HPB do not exceed 0.17 m3/h and 0.07 m3/h, which represent improvements of 95.34 % and 96.59 %, respectively.

A comparative study on the reducing flow rate design method for a desalination energy recovery pump as turbine

The energy recovery and utilization of high-pressure brine are the key to reduce the cost. Reducing flow rate method (RFM) was put forward firstly to adapt pump as turbine (PAT) to a wide range of operating conditions in this paper. In order to validate advantages of the new method, three different designs of PAT were obtained, respectively, based on three different methods, which were, respectively, selection design method, forward curved method and RFM. Based on numerical method, the external energy characteristics, axial force and internal flow patterns of PATs were analyzed. Results show that matching of the blade inlet angle and flow angle at the blade leading edge has a great influence on the turbine flow patterns which are directly related to the efficiency of PAT. A PAT designed by the new design method RFM improves both the hydraulic efficiency and shaft power under design and partial load conditions. Moreover, the axial force of the PAT designed by RFM is reduced, which can improve the reliability of the PAT operation with high rotating speed.

Drilling and completion technologies for deep carbonate rocks in the Sichuan Basin: Practices and prospects

The exploration and development of oil and gas resources in the Sichuan Basin is shifting to the deeper strata. The deep and ultra-deep wells in deep carbonate gas reservoirs are faced with many difficulties, such as multiple pressure systems, poor drillability, ultra-high pressure, ultra-high temperature and high sulfur content, which bring great challenges to drilling and completion engineering. In order to ensure the smooth exploration and development of deep carbonate oil and gas resources in the Sichuan Basin, the overall concept of combining field practice and technological research is followed. During the 13th Five-Year Plan, a batch of ultra-deep wells (well depth about 8000 m) have been drilled fast and safely (such as Well SYX133 in the Shuangyushi structure), and great progresses have been achieved in the experimental research of the support technologies in drilling and completion of deep and ultra-deep wells. And the achievements are as follows. First, the optimization of non-standard well structure, combined with the application of precisely managed pressure drilling technology and under-pressure plugging technology, lays a foundation for the optimized fast drilling and the safe reaching of geological targets. Second, a high-efficiency customized PDC drill bit is comprehensively optimized, popularized and applied, which effectively improves the average rate of penetration (ROP) in difficult-to-drill formations. Third, the development and application of drilling fluids (e.g. being resistant to high temperature of 200 °C and anti-composite brine) and active under-pressure plugging technology effectively reduces downhole complexities while drilling the complex formations, such as high temperature and high pressure brine and circulation loss. Fourth, when precisely managed pressure drilling and precisely managed pressure cementing methods are applied in the strata with a narrow density window, multiple pressure systems and pressure sensitivity, the average drilling and completion fluid loss is reduced by more than 90%, and the complexity treatment time is cut down by more than 85%, and the cementing quality pass rate is increased by more than 20%. Fifth, the integrated application of ROP improvement technologies and tools (e.g. air drilling) results in a great reduction of drilling cycle and cost. It is concluded that the experimental research achievements provide basic support for the fast development of natural gas resources in the Anyue Gas Field, Sichuan Basin, and the great discovery of the Permian and Devonian natural gas resources in the northwestern Sichuan Basin. What's more, in order to adapt to the development of the deep natural gas (over 9000 m) in the Sichuan Basin during the 14th Five-Year Plan, it is necessary to speed up researches on drilling and completion technologies in nine aspects, e.g. high-temperature downhole tools and working fluid.

Theoretical analysis and auxiliary experiment of the optimization of energy recovery efficiency of a rotary energy recovery device

A rotary energy recovery device (RERD), as the energy saving equipment of seawater desalination system, has a great significance on reducing the energy consumption and permeate cost of the system. The high or low energy recovery efficiency directly determines whether the engineering application of the RERD can be widely used. In this paper, firstly, based on the calculation formula of energy recovery efficiency, the main impact factors of efficiency were analyzed theoretically, including processing capacity, the high and low pressure differentials, and the leakage of the device. Secondly, in order to carry out some required auxiliary tests smoothly, a new RERD was designed and manufactured, and a complete SWRO desalination system was also established. The results depicted that the energy recovery efficiency reached the maximum and the corresponding optimal processing capacity was about 12.15m3/h when the pressure of the low pressure seawater was 1.0bar, that of the high pressure brine was 60.0bar, and leakage of the device was 0.6m3/h. Furthermore, when processing capacity was kept 13m3/h constant and the efficiency was required to exceed 94%, under the existing operating conditions, the maximal leakage of the device was needed no more than 0.43m3/h.

Optimising Cheese Brining Times

In this article we detail the work conducted during MISG2014 on the brining of Gouda cheese for the Fonterra Cooperative Group. We consider three different mathematical models that aim to predict the salt content of cheese post-brining. The first is a diffusion model that accounts for the interstitial volume that is available for salt and water transport within the cheese. It predicts moisture content that agrees closely with data provided by Fonterra, and we show how modifications to the salt diffusivity and partial molar volume can improve the accuracy of the salt content predictions. The second model considers the moisture in the cheese to be in two phases---free moisture that contributes to the porosity of the cheese and is accessible to salt diffusion, and water that is bound by the cheese protein. The third model, referred to here as the salt-uptake model, is a reaction-diffusion model that considers salt being bound to the cheese matrix as it diffuses through the cheese. More work is required on this model to be able to draw conclusions regarding the cheese brining process. References P. W. Atkins. Physical Chemistry . Oxford University Press, 4th edition, 1990. G. Aylward and T. Findlay. SI Chemical data . John Wiley and Sons, 1974. D. A. G. Bruggeman. Calculation of the various physical constants of heterogeneous substances. I: Dielectric constants and conductivities of mixtures of isotropic substances. Annalen der Physik , 25:636–664, 1935. doi:10.1002/andp.19354160705 . G. Carey, N. Fowkes, A. Staelens, , and A. Pardhanani. A class of coupled nonlinear reaction diffusion models exhibiting fingering. Journal of Computational and Applied Mathematics , 166(1), 2004. doi:10.1016/j.cam.2003.09.037 . R. Datta and S. A. Vilekar. The continuum mechanical theory of multicomponent diffusion in fluid mixtures. Chemical Engineering Science , 65:5976–5989, 2010. doi:10.1016/j.ces.2010.08.022 . C. J. D. Fell and H. Hutchison. Diffusion coefficients for sodium and potassium chlorides in water at elevated temperatures. Journal of Chemical and Engineering Data , 16:427–429, 1971. doi:10.1021/je60051a005 . Fonterra Co-Operative Group. Personal communication. 2014. T. J. Geurts, P. Walstra, , and H. Mulder. Transport of salt and water during salting of cheese. 1: Analysis of the processes involved. Netherlands Milk and Dairy Journal , 28:102–129, 1974. T. P. Guinee. Salting and the role of salt in cheese. International Journal of Dairy Technology , 57(2):99–109, 2004. doi:10.1017/S0022112003005512 . T. P. Guinee and P. Fox. Sodium chloride and moisture changes in romano–type cheese during salting. Journal of Dairy Research , 50:511–518, 1983. doi:10.1017/S002202990003274X . J. A. Luna and M. S. Chavez. Mathematical model for water diffusion during brining of hard and semi–hard cheese. Journal of Food Science , 57:55–58, 1992. doi:10.1111/j.1365-2621.1992.tb05423.x . K. Mandl, R. W. Hartel, and W. Wendorff. Effects of moisture and salt migration on cheese firmness in cheese–in–sausage products. Journal of Food Engineering , 91:164–172, 2009. doi:10.1016/j.jfoodeng.2008.08.022 . MATLAB. version 8.1 (R2013a) . The MathWorks Inc., Natick, Massachusetts, 2013. W. Messens, K. Dewettinck, and A. Huyghebaert. Transport of sodium chloride and water in gouda cheese as affected by high–pressure brining. International Dairy Journal , 9:569–576, 1999. doi:10.1016/S0958-6946(99)00126-0 . M. R. Payne and K. R. Morison. A multi–component approach to salt and water diffusion in cheese. International Dairy Journal , 9:887–894, 1999. doi:10.1016/S0958-6946(99)00157-0 . M. Turhan and G. Kaletunc. Modeling of salt diffusion in white cheese during long–term brining. Journal of Food Science , 57:1082–1085, 1992. doi:10.1111/j.1365-2621.1992.tb11269.x . H. Weingartner. Self–diffusion in liquid water. A reassessment. Zeitschrift fur Physikalische Chemie , 132:129–149, 1982. doi:10.1524/zpch.1982.132.2.129 .

Analysis, experiment and application of a power-saving actuator applied in the piston type energy recovery device

A piston type energy recovery device (ERD) can reduce the power consumption of seawater desalination system effectively, but the necessity of the oil hydraulic actuator for the ERD weakens the economics of the device and brings peripheral issues such as increased footprint. In this paper, a water hydraulic actuator driven by the high pressure brine of the desalting system is proposed to resolve the above problem and applied in the piston type reciprocating-switcher ERD (RS-ERD) to testify its effectiveness. The superiority evaluation proves that a reduction of up to 90.3% of the driving power consumption can be obtained by using the water hydraulic actuator, whose capital and maintenance costs are significantly lower than that of the oil hydraulic actuator. The experiments in the emulate test platform show that the RS-ERD with the water hydraulic actuator is operationally feasible and achieves high energy recovery efficiency of above 97%, except the existence of pressure pulsation (23.1%) in high pressure brine stream. Additionally, long term demonstration in the nanofiltration desalination system proves that the RS-ERD with water hydraulic actuator has a good operational reliability whose pressure pulsation has been dramatically minimized to 3.3% while maintaining the efficiency as high as 96%.

New Strong Inhibitory Polyamine Drilling Fluid System Research in Yubei Area

Yubei area exist thick mud shale, mudstone, gypsum mudstone and high pressure brine formation. In the course of drilling, the problems are most conspicuous which include well bore instability, bit balling and so on. In allusion to complex formation and complex accident, the polyamine form strong inhibitory polyamine collapse prevention drilling fluid on the basis of KCl-polysulfonate drilling fluid system was used in Yubei area. After the analysis on the mechanism of the strong inhibitory polyamine polymer drilling fluid system, the polyamine performance evaluation test made in laboratory shows that the drilling fluid system has good rheological property, high temperature resistance, clay and salt water pollution resistance. This drilling fluid system cooperate with KCl improve the ability of inhibition of drilling fluid, meet the requirements of stabilize borehole wall, which carried on the field test in YB A well has obtained good application effect.

Mass transfer dynamics during high pressure brining of chicken breast

The objectives of this study were to investigate the changes in mass transfer, textural properties and water holding capacity of chicken breast when brine treated under different pressures. Chicken breasts were treated for up to 20min in 4% sodium chloride solution under five pressures: 50, 100, 150, 200, and 300MPa at 25±1°C. The results indicated that the total weight and water uptake of the chicken breast increased with increasing pressure up to 150MPa, and then decreased with further pressure increase up to 300MPa. Chicken breast samples brined at 150MPa, with a sodium chloride effective diffusivity value of 2.96×10−8m2/s, exhibited minimum hardness and maximum water holding capacity. In general, pressure treatment at 150MPa was found to be the most suitable level for curing based on its higher yield, effective diffusivity and improved texture and water holding capacity.

The relation between Cu/Au ratio and formation depth of porphyry-style Cu–Au ± Mo deposits

Constraints on gold and copper ore grades in porphyry-style Cu–Au ± Mo deposits are re-examined, with particular emphasis on published fluid pressure and formation depth as indicated by fluid inclusion data and geological reconstruction. Defining an arbitrary subdivision at a molar Cu/Au ratio of 4.0 × 104, copper–gold deposits have a shallower average depth of formation (2.1 km) compared with the average depth of copper–molybdenum deposits (3.7 km), based on assumed lithostatic fluid pressure from microthermometry. The correlation of Cu/Au ratio with depth is primarily influenced by the variations of total Au grade. Despite local mineralogical controls within some ore deposits, the overall Cu/Au ratio of the deposits does not show a significant correlation with the predominant type of Cu–Fe sulfide, i.e., chalcopyrite or bornite. Primary magma source probably contributes to metal endowment on the province scale and in some individual deposits, but does not explain the broad correlation of metal ratios with the pressure of ore formation. By comparison with published experimental and fluid analytical data, the observed correlation of the Cu/Au ratio with fluid pressure can be explained by dominant transport of Cu and Au in a buoyant S-rich vapor, coexisting with minor brine in two-phase magmatic hydrothermal systems. At relatively shallow depth (approximately <3 km), the solubility of both metals decreases rapidly with decreasing density of the ascending vapor plume, forcing both Cu and Au to be coprecipitated. In contrast, magmatic vapor cooling at deeper levels (approximately >3 km) and greater confining pressure is likely to precipitate copper ± molybdenum only, while sulfur-complexed gold remains dissolved in the relatively dense vapor. Upon cooling, this vapor may ultimately contract to a low-salinity epithermal liquid, which can contribute to the formation of epithermal gold deposits several kilometers above the Au-poor porphyry Cu–(Mo) deposit. These findings and interpretations imply that petrographic inspection of fluid inclusion density may be used as an exploration indicator. Low-pressure brine + vapor systems are favorable for coprecipitation of both metals, leading to Au-rich porphyry–copper–gold deposits. Epithermal gold deposits may be associated with such shallow systems, but are likely to derive their ore-forming components from a deeper source, which may include a deeply hidden porphyry–copper ± molybdenum deposit. Exposed high-pressure brine + vapor systems, or stockwork veins containing a single type of intermediate-density inclusions, are more likely to be prospective for porphyry–copper ± molybdenum deposits.

Technical and economic comparison between PV-RO system and RO-Solar Rankine system. Case study: Thirasia island

This paper presents the technical characteristics as well as an economic comparison of two autonomous desalination systems. The first system concerns the laboratory experimental results of a direct coupled PV-SWRO desalination system without batteries equipped with a hydraulic energy recovery device of the Clark pump type. The PV system consists of 18 Arco-Solar monocristaline PV panels, with total peak power of 846 W. These panels are directly connected to a brushless DC motor of 510 W, powering a rotary vane pump as low pressure pump. The clark pump utilizes the high pressure brine to intensify the feed pressure to the RO desalination system. The desalination system has a capacity of 0.1 m 3/h. The specific energy recovery of this system has been experimentally found to be in the range of 3.8–6 kWh/m 3 depending on the feed water temperature and the feed water salinity. The second system is an organic solar Rankine system for RO desalination. The heat produced by the solar collectors’ field is transformed to mechanical power through an organic Rankine cycle process. The shaft power produced drives the high pressure pump of the RO unit, initiating the desalination process. The prototype system consists of vacuum tube solar collectors 90 m 2, a Rankine engine of 100 kW and an RO unit of 0.3 m 3/h. The energy recovery system of the RO unit consists of a pair of axial piston pumps (APP) manufactured by Danfoss. One of them operates reversely, as turbine, exploiting the hydraulic energy of the brine stream. The aim of the economic analysis is not only to estimate the cost of each system but also to compare them on the same basis, in order to allow a meaningful comparison. Hence, each system cost is determined having utilised the same economic assumptions like interest, operating expenses, etc. Moreover, these desalination systems can provide sufficient amounts of potable water for the local needs of a small island, like Thirasia, (Cyclades, Greece) at a cost as low as 7.77 ɛ/m 3, very close to that of water hauling.

Parametric analyses of energy consumption and losses in SWCC SWRO plants utilizing energy recovery devices

The reduction of energy consumption constitutes one of the major thrust areas of research in SWRO desalination process industries. The cost of energy in the SWRO process is usually about 30 to 50% of the total production cost of water and can be as much as 75% of the operating cost, depending on the cost of electricity. Thus, energy forms the major contributing factor in determining the water production cost. Hence reducing the energy consumption, which is mainly due to wastage of energy in high-pressure brine, is a major goal of desalination industries. Excepting Jeddah and Al-Birk, all the SWCC SWRO plants are equipped with several types of energy recovery devices, which are utilized to recover otherwise wasted energy in the reject. These energy recovery devices (ERD) are of varying efficiencies and their ability to recover the wasted energy is different in each case. ERD performance is very much dependant on the operating parameters such as flow as well as pressure, which of course is influenced by the feed water temperature. This paper describes in detail the performance of several ERD systems used in various SWCC SWRO plants and compares their efficiencies with regard to operating conditions for a period of one year and its effect on total energy saving and total power consumption by the high pressure pump in addition to the energy loss occurring in the process stream of SWRO plants. The average overall efficiency of the ERDs ranged from 3.2% to 65% which enabled savings of about 1.5% to 27% of total energy consumed by the high pressure pump. The average power consumed by the high pressure pump was in the range of 5.56–7.93 kWh/m 3. However, it was observed that a substantial amount of energy is lost by throttling that ranged from 6.4% to 21.8% of the total energy input to the high pressure pump. It was found that only at Al-Jubail plant, the performance of ERD was affected by the seasonal variation in operation parameters and for the rest of the plants the variation was not large enough to cause any significant change in the ERD performance.

Preliminary design of an underground reservoir for pumped storage

The current interest in the potential utilization of subsurface space for the storage of a wide variety of materials is responsive to the increasing pressures of environmental concerns, particularly as it applies to the development of urban or suburban space. These pressures, in conjunction with the continuing development of underground excavation technology, combine to provide a situation within which the concept of subsurface space utilization is becoming increasingly attractive relative to more conventional surface developments. Underground pumped storage is currently an economically viable alternative to the conventional above ground type of facility, and is made increasingly attractive by consideration of the reduced environmental impact, which the underground concept make possible. This paper is intended to provide an introduction to the engineering challenges of underground pumped storage, with particular reference to a limestone mine located some 671 m below the ground surface and having a volume of 9.6 million m3. To this end, the paper presents the numerical modeling and analyses to establish a powerhouse setting that would provide both a structurally stable excavation under the loading conditions imposed by the high-pressure brine, and eliminate the possibility of significant brine inflow to the excavated caverns.

Transport of sodium chloride and water in Gouda cheese as affected by high-pressure brining

Abstract The possibility of accelerating Gouda cheese brining by high-pressure treatment (100–500 MPa, 15–130 min) was investigated by comparison of the salt uptake of pressure-brined and nonpressure-brined Gouda cheese cylinders (∼8 g). The total amount of salt taken up by the cylinders was proportional to the square root of the brining time and was not influenced by pressure brining. In contrast, the water loss of the cheese cylinders was reduced by pressure brining at pressures above 200–300 MPa. No additional effect of a three-cycle process at 400 MPa was noticed on the salt uptake and water loss of the cheese cylinders. Moreover, the salt and water profiles of cheese (∼1.5 kg) brined for 24 h at 0.1 and 400 MPa were unaffected by high pressure. It was concluded that the salt uptake and salt diffusion cannot be accelerated by high-pressure brining, under the conditions specified.

Pressure exchange system for energy recovery in reverse osmosis plants

By application of a pressure exchange system (PES), which is already in use in other domains, a considerably higher efficiency of energy recovery in reverse osmosis (RO) systems may be achieved than with the use of reverse running pumps or turbines. The PES is suited, above all, for larger plants, i.e., approx. ≥2000 m 3/d permeate production. It enables a simple, variable adaption of discharge volume and has, due to its design and direct pressure transmission of high pressure brine to the feed, an efficiency value of approximately 98%. Therefrom results an economic energy recovery, amortization times for such systems varying between 2 and 4 years depending on the place of operation. The following are presented and explained: (1) technical details of the PES; (2) practical experience with PES in the mining industry with pressures between 4 and 16 MPa; (3) conception of the application in RO systems with individual and parallel trains; (4) economical calculations at the example of a demonstration system; and (6) concept and design of a demonstration system for an existing RO plant.