Analysis of Absorption Cooling and MD Desalination Cogeneration System

This work experimentally evaluates and compares the performance of four membrane distillation (MD) units with and without an internal gap rotating impeller blade. The novelty of the current study lies in the installed impeller within the condensation cavity and the impeller design parameters. The investigated MD units include a novel modified water-gap MD (M-WGMD) system featuring an internal impeller blade; a novel modified air-gap MD (M-AGMD) system with an internally rotating impeller blade; a regular water-gap MD (WGMD) process; and a conventional air-gap MD (AGMD) system. The evaluated system performance index includes gained output ratio (GOR) and vapor flux. The performance of the four MD systems is assessed and compared against each other under the same test conditions for various system design and operating variables, including impeller blade material, impeller blade angle, saline feed temperature, coolant temperature, and saline feed flowrate. Findings indicate that M-WGMD and WGMD systems (modified and conventional) produce higher flux than M-AGMD and AGMD units. Meanwhile, air-gap MD units (AGMD and M-AGMD) exhibits better energy efficient (higher GOR) than WGMD and M-WGMD systems. Furthermore, modified MD systems recorded superior performance compared to conventional MD systems and the blade angle effect is more influential than the blade material. At 80 °C feed temperature and 3200 mg/L feed salinity, the M-WGMD reaches a maximum flux of 128.39 kg/m2h and a GOR of 0.7702. On the other hand, the WGMD attained a flux of 67.32 kg/m2h and a GOR of 0.6199. The M-AGMD recorded a flux of 30.20 kg/m2h and a GOR of 0.8696. For the AGMD system, the GOR and the flux values are 0.7357 and 15.58 kg/m2h, respectively.

Hybrid multi-stage flash (MSF) and membrane distillation (MD) desalination system for energy saving and brine minimization

Mechanical vapor compression—Membrane distillation hybrids for reduced specific energy consumption

Direct contact membrane distillation (DCMD) process for simulated brackish water treatment: An especial emphasis on impacts of antiscalants

Performance simulation of solar-driven absorption heat pump-membrane distillation system for combined desalination brine concentration with feed recirculation and cooling applications

The assessment of microorganism growth in the membrane distillation system

In this paper, we present the treatment of humic acid solution via carbon nanotube immobilized membrane (CNIM) distillation assisted by air sparging (AS). Carbon nanotubes offer excellent hydrophobicity to the modified membrane surface and actively transport water vapor molecules through the membrane to generate higher vapor flux and better rejection of humic acid. The introduction of air sparging in the membrane distillation (MD) system has changed the humic substance fouling by changing the colloidal behavior of the deposits. This modified MD system can sustain a higher run time of separation and has enhanced the evaporation efficiency by 20% more than the regular membrane distillation. The air sparging has reduced the deposition by 30% in weight and offered lesser fouling of membrane surface even after a longer operating cycle. The water vapor flux increased with temperature and decreased as the volumetric concentrating factor (VCF) increased. The mass transfer coefficient was found to be the highest for the air sparged—carbon nanotube immobilized membrane (AS-CNIM) integrated membrane distillation. While the highest change in mass transfer coefficient (MTC) was found for polytetrafluoroethylene (PTFE) membrane with air sparging at 70 °C.

Zero liquid discharge treatment of brackish water by membrane distillation system: Influencing mechanism of antiscalants on scaling mitigation and biofilm formation

The main challenge for implementing an industrial-scale membrane distillation (MD) system is its associated thermal power demand and resulting operational cost, which hinders the commercialization of the technology, even after forty years of its evolution and development. Nevertheless, an enormous amount of waste heat releasing from the nano-electronics facilities provides MD an opportunity to showcase its potential for treating industrial wastewater discharging from the facilities. In this work, a waste heat driven MD system for a plant capacity of 15 m3/h was analyzed in terms of its thermal power demand and unit wastewater treatment cost. The economic analysis was performed using the factored estimate method. The results show that the thermal power requirement of the industrial-scale MD system was 12.38 MW, and the unit water treatment cost can vary between 3-23 $/m3, based on plant type (i.e., retrofitted facility or new wastewater treatment facility).•Determination of various industrial waste heat sources in typical nano-electronics fabrication facilities via interviews of related professionals, and designed industrial-scale waste heat integrated MD system for nano-electronics industries•Mass and energy balances around the industrial-scale MD system for wastewater treatment in nano-electronics industries•Equipment design for the purpose and performed economic evaluation of the MD system by customizing factored estimate method

Although the costs of desalination have declined, traditional desalination systems still need large amounts of energy. Recent advances in direct contact membrane distillation can take advantage of low-quality renewable heat to desalinate brackish water, seawater, or wastewater. In this work, the performance of a direct contact membrane distillation (DCMD) system driven by salt-gradient solar ponds was investigated. A mathematical model that couples both systems was constructed and validated with experimental data available in the scientific literature. Using the validated model, the performance of this coupled system in different geographical locations and under different operational conditions was studied. Our results show that even when this coupled system can be used to meet the future needs of energy and water use in a sustainable way, it is suitable for locations between 40°N and 40°S that are near the ocean as these zones have enough solar radiation, and availability of excess water and salts to operate the coupled system. The maximum freshwater flow rates that can be obtained are on the order of 3.0 L d−1 per m2 of solar pond (12.1 m3 d−1 acre−1), but the expected freshwater production values are more likely to be on the order of 2.5 L d−1 per m2 of solar pond (10.1 m3 d−1 acre−1) when the system operates with imperfections. The coupled system has a thermal energy consumption of 880 ± 60 kWh per m3 of distillate, which is in the range of other membrane distillation systems. Different operational conditions were evaluated. The most important operating parameters that influence the freshwater production rates are the partial pressure of air entrapped in the membrane pores and the overall thermal efficiency of the coupled system. This work provides a guide for geographical zone selection and operation of a membrane distillation production system driven by solar ponds that can help mitigate the stress on the water-energy nexus.

Cradle-to-grave life cycle assessment of membrane distillation systems for sustainable seawater desalination

An economic evaluation of renewable energy-powered membrane distillation for desalination of brackish water

Effect of salt and metal accumulation on performance of membrane distillation system and microbial community succession in membrane biofilms

Chapter 14 - Membrane Distillation Hybrid Systems

Chapter 15 - Economics, Energy Analysis and Costs Evaluation in MD