Lithium bromide solutions, vapor

Sudoh, M., Takuwa, K., lizuka, H., and Nagamatsuya, K. (1997). Effects of thermal and concentration boundary layers on vapor permeation in membrane distillation of aqueous lithium bromide solution. J. Membr. Sci. 131, 1. 

The high solubility of the salt and resultant low water vapor pressure (58) of its aqueous solutions ate usehil ia absorption air conditioning (qv) systems. Lithium bromide absorption air conditioning technology efficiencies can surpass that of reciprocal technology usiag fluorochlorocarbon refrigerants. 

Absorber is a component where strong absorber solution is used to absorb the water vapor flashed in the evaporator. A solution pump sprays the lithium bromide over the absorber tube section. Cool water is passing through the tubes taking refrigeration load, heat of dilution, heat to cool condensed water, and sensible heat for solution coohng. 

Lithium bromide is used in absorption, refrigeration and air-conditioning systems. A highly concentrated solution of the salt is an efficient absorbent of water vapor. The vapor pressure of such solution is very low. Other applications include the use of the salt as a swelling agent for wool, hair and other organic fibers as a catalyst in dehydrohalogenation reactions and as a sedative and hypnotic in medicine. 

Development of a Stable Aqueous Membrane. An aqueous LiBr membrane was fabricated by soaking a porous 47 mm diameter cellulose acetate/nitrate membrane in a 3 M LiBr solution for 24 hours. The membrane was then exposed to a vacuum for 5 hours to remove the water while leaving the lithium bromide. It was then placed into the apparatus shown in Figure 7 and exposed to a nitrogen mixture containing approximately 10 mmHg water vapor until the pores filled via condensation. 

C. Absorption Refrigeration. Water is the refngerant in the absorption process. To allow it to evaporate and condense at the right temperatures, the whole process is under vacuum. There is no compressor between the evaporator and the condenser. Rather, the water vapor from the evaporator is picked up by absorption in a salt solution. Lithium bromide is the salt most frequently used. 

Nasirzadeh K, Neueder R, Kunz W (2005) Vapor pressures, osmotic and activity coefficients of electrolytes in protic solvents at different temperatures. 3. Lithium bromide in 2-propanol. J Solution Chem 34 9-24... 

Data on the two lithium salts which are useful for air dehydration are presented in Table 11-9 and Figures 11-49 and 11-50. As shown in the figures, lithium bromide is considerably more soluble in water, and the saturated solutions of this salt have a lower vapor pressure than lithium chloride solutions at the same temperature and thus can provide a greater degree of dehydration. For most operations, however, the degree of dehydration provided by lithium... 

Hgure 11-49. Vapor pressure of saturated solutions of lithium chloride and bromide. Data of Foote Minerals Company (1956)... 

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