Chapter 2.5 Measurements and control in freeze—desalination plants

Hahn, W.

doi:10.1016/0011-9164(86)90035-4

Cited by 8 publications

(5 citation statements)

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“…Freezing desalination has many advantages including theoretically lower energy consumption due to the lower heat of fusion compared to that of vaporization, and minimal scaling problems [27]. However, the complexity of the plant design required to handle the mixture of ice and water and the contamination of product water has hindered the wide commercialization of this process [27][28][29].…”

Section: Mechanisms Involving Phase Changementioning

confidence: 99%

Nanostructured materials for water desalination

et al. 2011

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Desalination of seawater and brackish water is becoming an increasingly important means to address the scarcity of fresh water resources in the world. Decreasing the energy requirements and infrastructure costs of existing desalination technologies remains a challenge. By enabling the manipulation of matter and control of transport at nanometer length scales, the emergence of nanotechnology offers new opportunities to advance water desalination technologies. This review focuses on nanostructured materials that are directly involved in the separation of water from salt as opposed to mitigating issues such as fouling. We discuss separation mechanisms and novel transport phenomena in materials including zeolites, carbon nanotubes, and graphene with potential applications to reverse osmosis, capacitive deionization, and multi-stage flash, among others. Such nanostructured materials can potentially enable the development of next-generation desalination systems with increased efficiency and capacity.

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Section: Mechanisms Involving Phase Changementioning

confidence: 99%

Nanostructured materials for water desalination

et al. 2011

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“…The process inefficiencies and heat leakages into the system necessitate the use of a heat removal system. In addition to the basic components shown in Figure 1 and the associated instrumentation and control systems for efficient operation, there are several auxiliary systems [5]. These include venting systems, feed deaerators and refrigerant strippers.…”

Section: The Freeze Concentration Processmentioning

confidence: 99%

“…Freeze concentration systems are divided into direct and indirect processes [3,5,27-301. Heist [29, 301 described extensively the various systems and the refrigeration cycles that can be employed.…”

Section: Freeze-concentration Technology Systemsmentioning

confidence: 99%

The Freeze Concentration Process and its Applications

Englezos

1994

Dev. Chem. Eng. Mineral Process.

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In this paper, the freeze concentration separation process is described and the status of its industrial applications is reviewed. The pilot plant and commercial applications in the chemical and food processing industry for desalination and environmental protection, and in the pulp and paper industry are summarized. The advantages of using this process in the various industrial sectors as well as the lirnitalions are delineated. The development of the clathrate hydrate process is also discussed. Finally, some anticipated developments are described.

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“…The resulting liquid refrigerant is recycled back into the crystallizer, and the product water is removed after exchanging heat with the feed in the feed-heat exchanger. The most important unit operations, when considering the economics of the overall separation process, are the crystallization stage (the formation of the crystals), and the separation and purification stage (the recovery of pure crystals) (Hahn, 1986;Heist, 1979).…”

Section: Basic Processmentioning

confidence: 99%

“…Freeze concentration systems can be divided into two groups, indirect (Heist, 1979;Hahn, 1986) and direct (TechCommentary 1988;Hahn, 1986;Emmermann et al 1973;Ziering et al 1974;Heist, 1979;. The system that is chosen to concentrate a particular solution will depend on the characteristics of the solution and the end-use of the product water.…”

Section: Technology Systemsmentioning

confidence: 99%

Crystallization of Mechanical Pulp Mill Effluents through Hydrate Formation for the Recovery of Water

Gaarder

Ngan

Englezos

1994

ACS Symposium Series

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This work presents data toward the development of a new zero-liquid discharge (ZLD) system, the aim of which is to concentrate a liquid effluent thereby recovering process water. The crystallization technology used in this work is clathrate hydrate crystal formation. A screening of clathrate hydrate formers was performed and three were chosen, propane, carbon dioxide, and a 30-70 mol% propanecarbon dioxide mixture. Experiments were carried out with these substances in a vessel that was immersed in a temperature controlled bath. The effluent samples used in this study were generated at four pulp mills, an unbleached and a bleached thermo-mechanical pulp mill (TMP1, TMP2), a bleached chemi-thermo-mechanical pulp mill (BCTMP), and a combined bleached BCTMP/TMP mill (CTMP).The aim of this work was two-fold. The prime objective was to study experimentally the formation of clathrate hydrate crystals in these effluents. Experiments were designed to measure: (1) The temperature and pressure conditions at which hydrates form in mechanical pulp mill effluent; (2) The induction time and the growth rate of crystal formation; and (3) The ability of this apparatus to concentrate the effluents in-situ. In addition, effluent characteristic tests were performed, and qualitative process characteristics were noted. A secondary objective was to perform a survey on the liquid effluents generated at TMP and CTMP mills. This survey focused on the type, concentration, source, and environmental impacts associated with the contaminants typically present in these effluents, on the current discharge regulations, and on the available treatment options.It was determined that hydrate crystals can form in these effluents at temperatures above the normal freezing point of water. The measurements were compared with similar hydrate formation data in pure water. It was also found that the presence of impurities did not cause any appreciable change in the hydrate crystal pressure and temperature formation conditions with the TMP and CTMP effluent samples, but that the BCTMP effluent, which had a high electrolyte and organic content, did affect these conditions. It was found that the induction period and growth rate of hydrate crystals are dependent on the driving force and the prior history of the effluent. And finally, that some level of in-situ concentration was attainable with our apparatus.

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Chapter 2.5 Measurements and control in freeze—desalination plants

Cited by 8 publications

References 0 publications

Nanostructured materials for water desalination

Nanostructured materials for water desalination

The Freeze Concentration Process and its Applications

Crystallization of Mechanical Pulp Mill Effluents through Hydrate Formation for the Recovery of Water

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