Outer drying steam triple-effect heat exchange system

Abstract

The invention relates to an outer drying steam triple-effect heat exchange system. A flow divider is arranged in the liquid phase space of a water-bath-type saturated steam generator, and a steam discharge pipeline of the flow dividier is sequentially provided with a steam water separator and a steam drying heat exchanger; overheated steam enters the flow divider through a pressure control valve; wet saturated steam from the saturated steam generator is heated into dry saturated steam by overheated steam; the dry saturated steam enters a main steam heat exchanger and becomes high-temperature condensation water after materials are heated for the third time; flash steam of the high-temperature condensation water heats the materials in the flash steam heat exchanger for the second time; condensed flash steam enters the condensation water heat exchanger; the condensation water in the high-temperature condensation water continuously releases sensible heat to heat the material for the first time; the condensation water after temperature reduction enters a water collecting tank, and is pumped into the saturated steam generator by a water supplying pump; and the aperture of the pressure control valve is regulated by a PLC (programmed logic controller) according to the material outlet temperature. The system achieves cascading utilization of steam heat energy, guarantees that the steam heat energy can be used up, and improves the energy efficiency.

Description

technical field [0001] The invention relates to a steam heat exchange system, in particular to an external drying steam three-effect heat exchange system. Background technique [0002] In indirect heat exchange, the heat exchange efficiency of saturated steam is higher than that of superheated steam, and the higher the degree of superheat, the lower the heat exchange efficiency. When there is only superheated steam source, it is necessary to reduce the temperature of the superheated steam to reduce the degree of superheat. Generally, steam desuperheaters such as spray desuperheater, surface desuperheater, etc. are used. The lower the superheat after desuperheating, the more serious the steam will be with water, and the worse the steam quality will be. If it is necessary to reduce the steam temperature to the saturation temperature corresponding to the required steam pressure, a water-bath saturated steam generator is usually used, also known as a water-bath steam desuperhea...

AI Technical Summary

Problems solved by technology

The shortcomings of the existing water-bath saturated steam generators are: the water content in the saturated steam is high, and the steam quality is poor

After the high-temperature condensed water enters the condensed water pipe, the pressure drops continuously along the way, part of the high-temperature condensed water flashes into steam, the volume expands by more than 1000 times, and the flow rate increases by about 10 times, which is very easy to form steam resistance; after the steam resistance, the back pressure of the trap increases , the pressure difference between the two ends of the trap decreases, and the drainage capacity decreases, resulting in the condensed water generated in the heat exchanger cannot be removed in time, the efficiency of the heat exchanger decreases, and the material temperature cannot meet the process requirements, thus affecting normal production

In order to ensure production, it is often necessary to open the shut-off valve in parallel with the steam trap for direct discharge. The steam pressure leaked from the shut-off valve offsets the steam resistance; although the production is guaranteed, the steam utilization rate is reduced and the steam consumption per unit product is increased.

Therefore, the heat exchange efficiency and energy efficiency of the existing heat exchange system are relatively low.

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