5t/h Waste Heat Boiler Used in Rotary Lime Kiln Production Line Project
Type Selection and Technical Parameters of Guangdong 5t/h Low Temperature and Low Pressure Waste Heat Boiler
1. Flue gas waste heat conditions of the project
1) Lime rotary kiln: two lines of 600t/d (one of which has not been built), and the current production is basically constant. The outlet temperature of waste heat flue gas from lime furnace is 292 ℃. The flue gas volume is about 80000Nm3/h; there is no specific data on the flue gas
| ingredients | N2 | CO2 | H2O | SO2 | O2 |
| Content (V%) | 60.84 | 27.65 | 3.6 | 0.02 | 7.9 |
The calculated total enthalpy of flue gas is: 52947651KJ/h. Due to the low sulfur content of the flue gas, the exhaust gas temperature of the waste heat boiler can reach 130-135°C, and the heat utilization of the waste heat of the flue gas is: 34692765KJ/h.
2. Waste heat boiler selection and technical parameters
The heat source of the boiler in this project comes from the flue gas discharged from the lime kiln. The boiler operates under negative pressure and requires good sealing. According to the flue gas and operation characteristics of the boiler, in order to improve the thermal efficiency of the boiler and make the boiler operate safely and stably, the following corresponding measures have been taken in the entire design of the boiler.
(1) The work is safe and reliable. The boiler design adopts the widely used horizontal flue type natural circulation waste heat boiler. The evaporation heating surface is designed according to the maximum flue gas parameters, leaving a margin to ensure that it can adapt to fluctuating flue gas parameters. A reasonable structure is adopted to ensure the safety of water circulation.
(2) Light weight and small size.
(3) Strong mobility. This type of boiler has small water capacity and fast start-up speed.
(4) The structure is simple, easy to manufacture and easy to install.
(5) The integrated frame structure makes boiler installation easier.
(6) The furnace wall adopts a metal guard plate; the manhole, the wall pipe (collector), and the joints of the guard plate are fully sealed; the header on the heating surface is built-in to ensure that the boiler does not leak.
Boiler indoor layout, all-steel structure, balanced ventilation, natural circulation drum boiler, and main technical parameters of a single waste heat boiler are shown in the table below:
| Rated evaporation | 5 t/h |
| Normal output | 4.79t/h |
| Rated steam pressure | 0.7 MPa |
| Rated steam temperature | 210°C |
| Feed water temperature | 105°C |
| Oxygen removal method | vacuum deaeration |
| quantity | 2 units |
Boiler thermal characteristics (rated conditions)
| Smoke loss | % | 24.5 |
| heat loss | % | 2 |
| Calculation of thermal efficiency | % | 73.5 |
| Total flue gas consumption | Nm3/h | 81000 |
| Inlet flue gas temperature | ℃ | 260 |
| exhaust temperature | ℃ | 130 |
3. Turbine generator set
According to the steam consumption of ~8.03kg/kwh steam turbine generator set at low temperature and low pressure, the power generation of steam turbine: 2x4790/8.03=1193KW. It can install a 1.2MW pure condensing turbogenerator set.
The main performance parameters of the steam turbine generator set are as follows:
- steam turbine
Rated power: 1.2MW
Inlet steam pressure: 0.5MPa
Inlet steam temperature: 200°C
Exhaust steam pressure: 0.01MPa
Number of units: 1
--dynamo
Rated power: 1.2MW
Speed: 3000r/min
Export voltage: 400V
Power factor: 0.80
Number of units: 1