Three-coil-pipe fuel gas smoke turbulent flow heat exchange device and method

Abstract

The invention relates to a three-coil-pipe fuel gas smoke turbulent flow heat exchange device and method. According to the device, a combustor, an inner-layer round coil pipe, a middle-layer round coil pipe and an outer-layer flat coil pipe serve as main bodies, the design including the inner-layer coil pipe, the middle-layer coil pipe and the outer-layer coil pipe is adopted, smooth coil pipes onthe inner layer and the middle layer are arranged in a staggered mode, so that a radiation closed hearth is formed; the flat coil pipe is adopted on the outer layer to cool and condense flue gas, sothat the heat efficiency of the boiler is effectively improved; and while the flue gas is cooled and condensed, the viscous resistance of the flue gas is increased, so that the flowing state of the flue gas is changed from turbulent flow to laminar flow, the heat exchange coefficient is increased, and the cooling and condensing capacity of the flue gas is enhanced. The inner-layer round coil pipeand the middle-layer round coil pipe are arranged in the staggered mode to form the radiation closed hearth, radiation heat can be greatly absorbed by the flue gas exhausted by the combustor accordingto the radiation quadruplicate law; and compared with an existing one-return-stroke flat coil pipe heat exchange wall, the manufacturing process is simpler, the heat exchange coil pipes are more compact, and the manufacturing cost is lower.

Description

technical field [0001] The invention relates to the technical field of enhanced heat transfer, high efficiency and energy saving, in particular to a three-coil gas flue gas turbulent heat exchange device and method. Background technique [0002] Natural gas is being widely used as a clean and environmentally friendly high-quality energy, and gas coil boilers are also required for future development as energy-saving and environmentally friendly products. Currently used gas coil boilers, one is that two heat exchange coils are set independently of each other and stacked together, only a single coil heat exchange during operation makes the thermal efficiency low, and it is impossible to make the best use of everything; The tubes are all flat coil tubes, and the manufacturing process of hydroformed flat coil tubes is complicated. It needs to be rolled and welded into round tubes by steel plates, and then the round tubes are cold-processed and deformed into oblong cross-section f...

AI Technical Summary

Problems solved by technology

Currently used gas coil boilers, one is that two heat exchange coils are set independently of each other and stacked together, only a single coil heat exchange during operation makes the thermal efficiency low, and it is impossible to make the best use of everything; The tubes are all flat coil tubes, and the manufacturing process of hydroformed flat coil tubes is complicated. It needs to be rolled and welded into round tubes by steel plates, and then the round tubes are cold-processed and deformed into oblong cross-section flat tubes, and the straight flat tubes are cold-processed and wound Coiled tubes are finally stress-relieved and annealed to obtain the finished coiled tube unit; during the processing of the coiled tubes, the amount of cold working deformation is large, and there are residual stresses and lattice defects; The number of turns, which greatly increases the total heat transfer area of ​​the coil and the weight of the boiler; third, the traditional gas-fired coil boiler has special requirements for heat transfer, the heat exchanger is large in size, and the smoke and wind resistance is large. The operating costs are high, and the exhaust gas temperature cannot meet the requirements, making it difficult to apply

[0003] In addition, every 1m 3 There are about 2.1-2.3m in the combustion products of natural gas (methane accounts for about 85%) 3 The latent heat steam is converted according to the calorific value of 8000-8500 kcal per cubic meter of natural gas, and the latent heat of water vapor at 0.1MPa and 100°C is 2257kj / kg. The latent heat loss of steam in the low heating value accounts for about 9.57% of the total heat of natural gas combustion. However, this part of the heat has not been fully utilized in the current boilers, so the demand for natural gas in gas-fired boilers has been high, resulting in huge energy losses

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