Flue Gas Water Recovery by Indirect Cooling Technology for Large-Scale Applications: A Review

With social development and economic enhancement, energy is facing significant worldwide demand, and fossil fuels are the prime energy sources for various energy systems over past decades. Furthermore, among fuel-consumed applications, power plants are the primary source of energy consumption. There is a lot of waste heat and steam accompanied by the latent heat produced in the exhaust flue gas. Therefore, the latent heat recovery from the flue gas plays an important role in increasing the efficiency of the system and saving water. To recover the heat and mass in power plants, three primary methods are proposed to condense the vapor based on previous studies: (1) flue gas condensation technology, (2) liquid desiccant-based dehydration (LDD) technology and (3) membrane technology. This paper mainly reviews and summaries the indirect cooling technology in flue gas condensation technology. The numerical simulation and theory of flue gas condensation are introduced. Different heat exchanger types and conducted experiments are also summarized. The performance of the indirect cooling technology is affected not only by its own configuration and design but also by the flue gas inlet temperature, velocity, water vapor mass fraction, etc. The major concerns and outlook of practical applications for further study are attributed to the heat exchanger size and cost, acid corrosion, ash accumulation in flue gas, etc.