What is a double-pressure boiler?

The inlet and outlet flue of the waste heat boiler is provided with expansion joints to absorb the expansion of various components of the boiler. Moreover, the boiler body is equipped with expansion guide device to ensure the free expansion of the furnace body, limit the displacement and prevent the deformation and vibration of the furnace body. In order to ensure the sealing effect of the waste heat boiler, the overall layout of the waste heat boiler adopts the membrane wall structure, which not only ensures the sealing and insulation effect, but also reduces the accumulation of ash slag and improves the efficiency of the waste heat boiler.

Double-pressure boiler means that there are two groups of water circulation with different working pressures in the boiler to produce two kinds of new steam with different pressures, so it is called double-pressure boiler. Double-pressure boiler is usually used as waste heat boiler, which has the advantage of improving the equivalent heat efficiency of waste heat boiler.

Why should we set up two groups of water circulation with different pressures?

This is because the waste heat boiler usually does not have an air preheater to recover the low temperature heat energy of flue gas, so the flue gas temperature mainly depends on the temperature when flowing through the feed water heater. The maximum temperature of flue gas in the waste heat boiler is lower than that of the ordinary boiler, which results in that the steam flow generated by the waste heat boiler is smaller than that of the ordinary boiler under the same flue gas flow, that is, the steam gas ratio is smaller.

There are node temperature difference and approach point temperature difference in the steam boiler. Therefore, if the steam to gas ratio is small, the flue gas temperature of the feedwater heater after the evaporator will drop slowly, and the flue gas temperature of the boiler will be high. In order to improve the thermal efficiency of the waste heat boiler, the double-pressure boiler appeared. Add another set of water circulation with low temperature and pressure in the double-pressure boiler. Because of its low evaporation temperature, it can effectively reduce the emission temperature of flue gas and improve the thermal efficiency of the boiler.

Compared with single-pressure waste heat boiler, the disadvantage is that the system is a little complex.

In some cases with higher requirements for thermal efficiency, there are three-pressure waste heat boilers. The equivalent thermal efficiency is higher (but the improvement is not as large as that from single pressure to double pressure), and the system is also more complex.

The above is Jiangsu Sifang Clean Energy Equipment Manufacturing's answer to this question. If you have any questions about other boiler related issues, please consult Jiangsu Sifang Clean Energy Equipment Manufacturing's online customer service or call 0516-85871846 or 0516-85532705. Jiangsu Sifang Clean Energy Equipment Manufacturing's professional technicians will answer your questions in time.