Study On Optimization And Application Of Flow And Heat Transfer Of Flue Gas In Heat Recovery Device

With the implementation of the world's sustainable development strategy, optimization of energy structure and development of low-carbon economic, it has been put a higher demand for efficient use of natural gas. Flue gas condensation heat recycling device is a device added in the thermal power equipment recycling the tail gas waste heat and plays significant role in the energy field. It is becoming a hot topic in fields of international energy resources environment and engineering application department to development new technology equipments on high efficiently using natural gas.This paper aimed at optimizing flue gas condensation heat recycling device. Using theoretical analysis, numerical simulation and experimental method of combining engineering, study on the flow and heat transfer of flue gas in flue gas condensation heat recycling device and optimize the device structure.For flue gas condensation in the flue gas heat recovery device using vertical flow and horizontal flow of two cases, used CFD software Fluent to simulate the flow field and temperature field of the flue gas condensing heat recycling device. Combined with the measured results of the engineering application, optimized the device structure.Explore the formula matching on the flue gas heat recovery device. With the CFD software Fluent to simulate the flow field of it and analyze the relationship between flue gas flow resistance R and the inlet velocity v. Obtained in the v=1.0～3.0m/s range of 1 to 7 layers of the main section of the flue gas heat exchanger fitting formula for the resistance R=a·vb.It presents an application of flue gas condensing heat recovery system for gas boiler energy saving engineering. When the gas-fired boiler of 2.5MW at part load (53%) operating conditions, the flue gas temperature dropped from 130℃to 40℃the boiler efficiency can be increased more the 9% and the total efficiency is up to 106%. That can save gas 15.3Nm3/h, the entire heating season, it can save gas by 51660Nm3/a, fuel savings by 10 million Yuan/a. The energy-saving effect is remarkable. Combined with the measured data, analyses the energy-saving on heat recycling system and the regulation and operation of boiler systems. Based on the analysis, provides some optimized schemes for the existing boiler system.The results for the study provides a reference for similar multi-component heat and mass transfer, provides a technical support for optimizing the flue gas heat recovery device, and provides the basis for the optimal operation of the boiler system. It is important for both theoretical and practical issues.