英语翻译In theory,a large amount of energy can be extracted from

英语翻译In theory,a large amount of energy can be extracted from the reversible mixing of a dilute stream with the ammonia–carbon-dioxide solution .Using low-grade heat at 50 °C,the thermal energy needed to separate the diluted ammonia–carbon-dioxide solution into water (low-concentration stream),and ammonia and carbon dioxide (that reform the high-concentration stream) is 358 MJ m-3 for a 1 M solution and 593 MJ m-3(165 kWh m-3) for a 2 M solution.Highly soluble inorganic salts,such as sodium chloride,can also be used in closed-loop heat engines with separation processes that use low-grade heat.For example,membrane distillation uses a vapour pressure gradient created by the temperature difference across the membrane to transport water vapour through microporous hydrophobic membranes.Thermal-energy requirements or membrane distillation can range from 40 kWh m-3 to 650 kWh m-3,depending on membrane properties,system design,heat source and operating temperature.To successfully implement closed-loop systems that use synthetic solutions,several challenges need to be addressed.The main challenge for PRO is the development of membranes with sufficient mechanical strength to withstand the high hydraulic pressures that occur with very high salt concentrations.For membrane distillation to be viable in these systems,efficient and low-cost membranes need to be developed.