Performance of new generation membrane distillation membranes

2009 ◽  
Vol 9 (5) ◽  
pp. 501-508 ◽  
Author(s):  
Jianhua Zhang ◽  
Mikel Duke ◽  
Eddy Ostarcevic ◽  
Noel Dow ◽  
Stephen Gray ◽  
...  
Keyword(s):  
Pore Size ◽  
Flow Rate ◽  
Waste Heat ◽  
Low Cost ◽  
Membrane Distillation ◽  
Inlet Temperature ◽  
Heat Sources ◽  
Water Recovery ◽  
Operational Conditions ◽  
Small Pore

Membrane distillation has been a known desalination process for many years, but its commercial implementation has been hampered by low water fluxes and the need for low cost heat sources. With greater emphasis being placed on energy efficiency, membrane distillation coupled with waste heat or solar heat sources to drive the process is being reconsidered. In particular, the use of membrane distillation to treat brine concentrates is receiving renewed attention, as it results in increased water recovery and lower brine discharges, and high salt concentrations do not increase the driving force requirements for membrane distillation. In this paper, four different membranes, one made of polyvinylidenefluoride (PVDF) and three made of polytetrafluoroethylene (PTFE) of different pore sizes, were assessed the performance in membrane distillation under different hot feed flow rates and inlet temperatures. The results show that the PTFE membranes had a much higher flux than that of PVDF at the same operational conditions, and PTFE membranes of large pore size produced higher flux than that of the small pore size. The results also showed that increasing the flow rate of the hot feed and its inlet temperature increased the flux, but the rates of increase decreased with increasing flow rate and inlet feed temperature.

scholarly journals Experimental evaluation of two consecutive air-gap membrane distillation modules with heat recovery

2020 ◽  
Vol 20 (5) ◽  
pp. 1678-1691 ◽  
Author(s):  
Mostafa Abd El-Rady Abu-Zeid ◽  
Gamal ElMasry
Keyword(s):  
Water Temperature ◽  
Flow Rate ◽  
Heat Recovery ◽  
Waste Heat ◽  
Water Flow Rate ◽  
Membrane Distillation ◽  
Air Gap ◽  
Feed Water ◽  
System Productivity ◽  
Air Gap Membrane Distillation

Abstract Two rectangular modules with a total interior membrane surface area of 13.53 m2 were consecutively combined to evaluate the use of heat recovery in an air-gap membrane distillation (AGMD) system. Several operating inlet parameters including feed water temperature, mass water flow rate and salinity were investigated. The experimental results revealed that the performance of the system was improved by virtue of efficient heat recovery resulting from combining two AGMD membrane modules in series. Under optimal inlet operating parameters of cooling water temperature of 20 °C, salinity of 0.05% and flow rate of 3 l/min, the system productivity (Pp) increased up to 192.9%, 179.3%, 176.5% and 179.2%, and the thermal efficiency (ηth) by 261.5%, 232.6%, 239.4% and 227.3% at feed water temperatures of 45 °C, 55 °C, 65 °C and 75 °C, respectively. Concurrently, the specific waste heat input (Ew.h.i) decreased by 6.7%, 4.7%, 5.6% and 2.7% due to the efficient heat recovery. The results confirmed that heat recovery is an important factor affecting the AGMD system that could be improved by designing one of the two AGMD modules with polytetrafluoroethylene (PTFE) hollow fibers with a flow length shorter than the other one having a salt rejection rate of 99%.

Numerical Modeling and Simulation of Condensation Heat Transfer in a Bundle of Transport Membrane Tubes for Waste Heat and Water Recovery

2011 ◽  
Author(s):  
Cheng-Xian Charlie Lin ◽  
Dexin Wang ◽  
Ainan Bao
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Flue Gas ◽  
Transport Model ◽  
Waste Heat ◽  
Numerical Study ◽  
Tube Bundle ◽  
Inlet Temperature ◽  
Water Recovery ◽  
Species Transport

In this paper, a numerical study has been carried out to investigate the heat and mass transfer with condensation in a transport membrane tube bundle, which is used for recovering both heat and water from combustion flue gas. The tube wall is made of a specially designed porous material that is able to extract condensate liquid from the flue gas. The flue gas investigated consists of one condensable water vapor (H2O) and three noncondensable gases (CO2, O2, and N2). A simplified multi-species transport model was developed for the heat and mass transfer of flue gas. The condensation-evaporation process was simulated as a two-step chemical reaction. The RNG two-equation turbulence model was used for the turbulent flow. The numerical study was conducted within ranges of Reynolds number of 1.0×103–7×104 based on hydraulic diameter of flue gas channel, and 6.4×100–3.3×102 based on inner diameter of the water tube. Flue gas inlet temperature is within the range of 333.2–360.9 K, while the water inlet temperature is within the range of 293.9–316.7 K. Numerical results were compared with experimental data obtained in a parallel effort. It has been found that the developed multi-species transport model was able to predict the flue gas heat and mass transfer in the tube bundle with fairly good accuracy. The heat and mass depletion levels decrease with the increase of the flue gas Reynolds numbers. A new Nusselt number correlation was developed for flue gas convection in the tube bundle. Detailed results about temperature, mass fraction, enthalpy, and skin fraction factors are also presented and discussed.

scholarly journals Study on the performance of Double-pipe phase heat exchangers in waste heat recovery with heat storage and discharge

2021 ◽  
Vol 2076 (1) ◽  
pp. 012002
Author(s):  
Quanying Yan ◽  
Yuan Guo ◽  
Chao Ma
Keyword(s):  
Heat Exchange ◽  
Flow Rate ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Storage Time ◽  
Heat Storage ◽  
Waste Heat ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Double Pipe

Abstract The heat transfer performance of the double-pipe phase change heat storage and exothermic device and its cycle system for waste heat recovery was studied experimentally. 10 different experimental conditions were set by adjusting the inlet temperature, inlet flow rate and heat storage time of the phase change heat storage and exothermic device to study the changes of the outlet temperature, heat exchange and the inlet and outlet temperature of the heat sink of the heat-using device. The experimental results show that the higher the inlet temperature, the higher the flow rate and the longer the heat storage time, the higher the average heat exchange and the longer the heat release time of the heat exchanging device. The phase heat exchanger designed and used in this experimental research provides a certain experimental basis and data reference, which can be used for waste heat recovery in industrial and other fields.

Investigation of the Bottoming Cycle for High Efficiency Combined Cycle Gas Turbine System With Supercritical Carbon Dioxide Power Cycle

2015 ◽  
Author(s):  
Seong Kuk Cho ◽  
Minseok Kim ◽  
Seungjoon Baik ◽  
Yoonhan Ahn ◽  
Jeong Ik Lee
Keyword(s):  
Gas Turbine ◽  
Flow Rate ◽  
High Efficiency ◽  
Waste Heat ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Power Cycle ◽  
Turbine Inlet ◽  
Steam Cycle

The supercritical CO2 (S-CO2) power cycle has been receiving attention as one of the future power cycle technology because of its compact configuration and high thermal efficiency at relatively low turbine inlet temperature ranges (450∼750°C). Thus, this low turbine inlet temperature can be suitable for the bottoming cycle of a combined cycle gas turbine because its exhaust temperature range is approximately 500∼600°C. The natural gas combined cycle power plant utilizes mainly steam Rankine cycle as a bottoming cycle to recover waste heat from a gas turbine. To improve the current situation with the S-CO2 power cycle technology, the research team collected various S-CO2 cycle layouts and compared each performance. Finally, seven cycle layouts were selected as a bottoming power system. In terms of the net work, each cycle was evaluated while the mass flow rate, the split flow rate and the minimum pressure were changed. The existing well-known S-CO2 cycle layouts are unsuitable for the purpose of a waste heat recovery system because it is specialized for a nuclear application. Therefore, the concept to combine two S-CO2 cycles was suggested in this paper. Also the complex single S-CO2 cycles are included in the study to explore its potential. As a result, the net work of the concept to combine two S-CO2 cycles was lower than that of the performance of the reference steam cycle. On the other hand, the cascade S-CO2 Brayton cycle 3 which is one of the complex single cycles was the only cycle to be superior to the reference steam cycle. This result shows the possibility of the S-CO2 bottoming cycle if component technologies become mature enough to realize the assumptions in this paper.

Development and Testing of a 10 MWe Supercritical CO2 Turbine in a 1 MWe Flow Loop

2020 ◽  
Author(s):  
Jeffrey Moore ◽  
Stefan Cich ◽  
Meera Day-Towler ◽  
Jason Mortzheim
Keyword(s):  
Power Density ◽  
High Efficiency ◽  
Environmental Changes ◽  
Waste Heat ◽  
Test Facility ◽  
Thermal Mass ◽  
Inlet Temperature ◽  
Heat Sources ◽  
Steam Turbines ◽  
Flow Loop

Abstract sCO2 power cycles offer improved cycle efficiencies compared with traditional steam Rankine cycles. However, the turbomachinery required to support such a cycle does not exist at a commercial scale and requires development. This paper describes a new 10 MWe scale sCO2 turbine was developed and demonstrated in an sCO2 closed-loop recompression Brayton cycle. Since this turbine was developed for Concentrating Solar Power (CSP) applications, a target inlet temperature of over 700°C was chosen using funding from the US DOE SunShot initiative and industry partners. However, it can be applied to traditional heat sources such as natural gas, coal, and nuclear power. Traditional Rankine steam cycle thermal efficiencies are typically in the 35–40% range, but can be as high as 45% for advanced ultra-supercritical steam cycles. The sCO2 cycle can approach 50% thermal efficiency using externally fired heat sources. Furthermore, this cycle is also well suited for bottoming cycle waste heat recovery applications, which typically operate at lower temperatures. The high-power density and lower thermal mass of the sCO2 cycle results in compact, high-efficiency power blocks that can respond quickly to transient environmental changes and transient operation, a particular advantage for solar, waste heat, and ship-board applications. The power density of the turbine is significantly greater than traditional steam turbines and is comparable to liquid rocket engine turbo pumps. This paper describes the design and construction of the turbine and provides additional testing of the 10 MWe turbine in a 1 MWe test facility including a description of rotordynamics, thermal management, rotor aero and mechanical design, shaft-end and casing seals, bearings, and couplings. Test data for the turbine is included, as it achieves its operational goal of 715°C, 250 bara, and 27,000 rpm.

scholarly journals Employing full factorial design and response surface methodology for optimizing direct contact membrane distillation operational conditions in desalinating the rejected stream of a reverse osmosis unit at Esfahan refinery–Iran

2018 ◽  
Vol 19 (2) ◽  
pp. 492-501 ◽  
Author(s):  
M. Ebadi ◽  
M. R. Mozdianfard ◽  
M. Aliabadi
Keyword(s):  
Response Surface Methodology ◽  
Reverse Osmosis ◽  
Flow Rate ◽  
Direct Contact ◽  
Membrane Distillation ◽  
Permeate Flux ◽  
Operational Conditions ◽  
Direct Contact Membrane Distillation ◽  
Full Factorial ◽  
Feed Temperature

Abstract Optimized condition for desalination of the reverse osmosis (RO) rejected stream from Esfahan Oil Refining Company (EORC) using direct contact membrane distillation (DCMD) with polytetrafluoroethylene (PTFE) membrane was investigated here, having designed a set of 34 experiments using response surface methodology (RSM) and full factorial design (FFD) modelling, carried out in a laboratory scale set-up built for this purpose. Statistical criteria for validation, significance, accuracy and adequacy confirmed the suitability of the quadratic polynomial model employed. Response plots and regression equations suggested that the permeate flux response improved with increased feed temperature, reduced permeate temperature and enhanced feed flow rate. Optimizing DCMD process showed that maximum permeate flux of 60.76 L/m2·h could be achieved at the following optimum operational conditions: feed temperature and flow rate of 70 °C and 2 L/min, respectively, as well as the permeate temperature of 15 °C. At this point, the mean annual energy required for 90% water recovery (36 m3/h off the RO brackish rejected stream) at EORC refinery was found to be 96 GJ, which could be supplied using solar or conventional energy systems at Isfahan, facing a very critical water shortage at present.

The Effects of Parameters on HRSG Thermodynamic Performance

2013 ◽  
Vol 774-776 ◽  
pp. 383-392 ◽  
Author(s):  
Hong Cui Feng ◽  
Wei Zhong ◽  
Yan Ling Wu ◽  
Shui Guang Tong
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Flue Gas ◽  
Waste Heat ◽  
Steam Pressure ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Pinch Point ◽  
Water Steam

Changes of inlet temperature, mass flow rate and composition of flue gas, or of water/steam pressure and temperature in heat recovery steam generator (HRSG), all will modify the amount of waste heat recovered from flue gas; this brings forward a desire for the optimization of the design of HRSG. For single pressure HRSGs with given structures and specified values of inlet temperature, mass flow rate and composition of flue gas, the steam mass flow rate and gas outlet temperature of the HRSG are analyzed as functions of several parameters. This analysis is based on the laws of thermodynamics, incorporated into the energy balance equations for the heat exchangers. Those parameters are superheated steam pressure and temperature, feedwater temperature and pinch point temperature difference. It was shown that the gas outlet temperature could be lowered by selecting appropriate water/steam parameters and pinch point temperature difference. While operating with the suggested parameters, the HRSG can generate more high-quality steam, a fact of great significance for waste heat recovery from wider ranges of sources for better energy conservation.

Advances in seawater membrane distillation (SWMD) towards stand-alone zero liquid discharge (ZLD) desalination

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Helen Julian ◽  
Novesa Nurgirisia ◽  
Putu Doddy Sutrisna ◽  
I. Gede Wenten
Keyword(s):  
Sea Water ◽  
Low Cost ◽  
Detailed Comparison ◽  
Pilot Scale ◽  
Membrane Distillation ◽  
Water Recovery ◽  
Feed Concentration ◽  
Liquid Discharge ◽  
Salt Recovery ◽  
Push Forward

Abstract Seawater membrane distillation (SWMD) is a promising separation technology due to its ability to operate as a stand-alone desalination unit operation. This paper reviews approaches to improve laboratory-to-pilot-scale MD performance, which comprise operational strategies, module design, and specifically tailored membranes. A detailed comparison of SWMD and sea water reverse osmosis is presented to further analyze the critical shortcomings of SWMD. The unique features of SWMD, namely the ability to operate with extremely high salt rejection and at extreme feed concentration, highlight the SWMD potential to be operated under zero liquid discharge (ZLD) conditions, which results in the production of high-purity water and simultaneous salt recovery, as well as the elimination of the brine disposal cost. However, technical challenges, such as thermal energy requirements, inefficient heat transfer and integration, low water recovery factors, and lack of studies on real-case valuable-salt recovery, are impeding the commercialization of ZLD SWMD. This review highlights the possibility of applying selected strategies to push forward ZLD SWMD commercialization. Suggestions are projected to include intermittent removal of valuable salts, in-depth study on the robustness of novel membranes, module and configuration, utilization of a low-cost heat exchanger, and capital cost reduction in a renewable-energy-integrated SWMD plant.

scholarly journals Facile fabrication of paper-based flexible thermoelectric generator

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Zuoyuan Dong ◽  
Hua Liu ◽  
Xin Yang ◽  
Jichen Fan ◽  
Hengchang Bi ◽  
...  
Keyword(s):  
Waste Heat ◽  
Low Cost ◽  
Commercial Application ◽  
Heat Sources ◽  
Wearable Electronics ◽  
Vacuum Filtration ◽  
Facile Fabrication ◽  
Self Powered ◽  
Human Powered ◽  
Flexible Thermoelectric

AbstractPaper, as a foldable, pollution-free, and low-cost material, has become a suitable support substrate for producing flexible thermoelectric (TE) generators to realize waste heat recycling and the application of human-powered electronic devices. We propose a facile fabrication method to modify cellulose paper with inorganic TE powders via vacuum filtration, making a modified paper that possesses good thermoelectric properties. By connecting the modified paper to copper foils, flexible paper-based TE generators (PTGs) are fabricated. The obtained PTG with three units of P–N modules can generate an output voltage of ∼41.2 mV at a temperature difference of 50 K. Based on this modified paper, a thermal sensor that responds to heat sources, such as fingers, is proposed with a rapid response time of 0.25 s. This work offers a promising strategy for the simple fabrication of PTGs, paving the way for achieving the commercial application of self-powered wearable electronics.

BIO-FUEL PRODUCTION FROM CARBONDIOXIDE GAS USING S. elongatus PCC 7942 FROM CYANOBACTERIA

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Delia Teresa Sponza ◽  
Cansu Doğanx
Keyword(s):  
Flow Rate ◽  
Maximum Yield ◽  
Butanol Production ◽  
Fuel Production ◽  
Cost Analyses ◽  
Operational Conditions ◽  
O2 Concentration ◽  
The Cost ◽  
Pcc 7942 ◽  
Dissolved O2

The scope of this study, is  1-butanol production from CO2 with S. elongatus PCC 7942 culture. The yields of 1-butanolproduced/CO2utilized have been calculated. The maximum concentration of produced 1- butanol is 35.37 mg/L and 1-butanolproduced/CO2utilized efficiency is 92.4. The optimum operational conditions were  30°C temperature, 60 W intensity of light, pH= 7.1, 120 mV redox potential, 0.083 m3/sn flow rate with CO2 and 0.5 mg/l dissolved O2 concentration. Among the enzymes on the metabolic trail of the production of 1-butanol via using S. elongatus PCC 7942 cyanobacteria. At maximum yield; the measured concentrations are 0.016 µg/ml for hbd; 0.0022 µg/ml for Ter and 0.0048 µg/ml for AdhE2. The cost analyses necessary for 1-butanol production has been done and the cost of 1 litre 1-butanol has been determined as maximum 1.31 TL/L.

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