flue gas waste heat recovery

High tech and innovative technology: a flue gas waste heat recovery system that prevents acid dew point corrosion!

1、 The function of flue gas waste heat recovery system:

1. Heat the boiler to replenish water and increase the inlet water temperature of the deaerator.

2. Raise the inlet air temperature of the air preheater and assist in adjusting the heating of desalinated water.

3. Used to heat the flue gas after desulfurization and increase the exhaust temperature.

4. Equipped with a heat pump system to provide cooling and heating for the thermal system and office area.

2、 Advantages of flue gas waste heat recovery system:

1. Reliable - Installed on the boiler bypass flue, the energy-saving system can be independently controlled without affecting the normal operation of the boiler.

2. Energy saving - reducing energy consumption, increasing steam production rate per ton of coal, and increasing boiler output can steadily improve boiler thermal efficiency by more than 1.5%.

3. Water saving - While recovering heat energy, reducing the exhaust temperature of the secondary desulfurization system can save a lot of water for desulfurization processes.
4. Corrosion prevention - adjustable and controllable metal wall temperature not lower than the condensation point (acid dew point) of sulfuric acid vapor, fundamentally solving the problem of equipment acid dew corrosion.
5. Emission reduction - saving energy consumption is the greatest emission reduction, reducing CO ₂ and NOx emissions while effectively reducing dust emissions.

3、 The principle of flue gas waste heat recovery system:

The inside of the heat exchange tube is phase change heat exchange, while the outside is convective heat exchange. In contrast, the phase change heat transfer coefficient is much higher than the convective heat transfer coefficient, so the wall temperature is mainly affected by the medium inside the tube, but not by the medium outside the tube.

Phase change heat transfer technology utilizes the technical principle of phase change heat transfer in heat pipe technology to create the concept of "phase change section". The concept of "phase transition section" is to creatively construct a whole heat pipe from the independent heat pipes in the original heat pipe heat exchanger; Ensure that the minimum wall temperature of the heating surface in the "phase transition section" has only a slight gradient temperature drop; At the same time, the temperature of the heated medium (such as air, water, etc.) is appropriately increased using the "phase transition stage"; A new concept of using "wall temperature" as the first design parameter for heat exchangers has been proposed, which changes the functional relationship between exhaust gas temperature and metal wall temperature. The metal wall temperature of the heat exchanger is in a controllable and adjustable state, and the preheated air and water can ensure the safety of downstream equipment, solving the problem of low-temperature corrosion; Recovering waste heat from flue gas through the heated medium to achieve energy-saving goals.

So, by controlling the saturation temperature of the internal medium, it is possible to achieve controllable and adjustable wall temperature of the phase change flue gas waste heat recovery system.
                         

4、 Energy saving calculation of phase change flue gas waste heat recovery system:

1. Calculation formula for heat recovery

In the formula: Vg - flue gas flow rate, unit: Nm3/h;

ρ g - smoke density, taken as 1.295 kg/Nm3;

Cpg - specific heat of flue gas, taken as 1.12 kJ/(kg. ℃);

Δ T - Temperature difference between the smoke before and after the application of the composite phase change heat exchanger, unit: ℃;

φ - Boiler heat retention coefficient;

Q - Heat recovery of phase change heat exchanger, unit: KW.

2. Calculation formula for equivalent coal consumption
          
In the formula: Q - heat recovered by the phase change heat exchanger, unit: KW;

HR - Annual operating hours of boiler;

Qnet - calorific value of coal, unit: kCal/kg;

η - boiler efficiency;

860- Conversion coefficient between "kcal" and "kWh" units;

Gc - Annual coal saving of the boiler.

Specification parameters:

              
          Need to know more: Thermal Energy Recovery Division
 

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