How to convert the gas production rate when boiler steam pressure decreases from high to low?
Thread Content
Our company has a boiler with a design pressure of 1.6 MPa and a production capacity of 65 t/h. The gas generation pressure for this boiler has now been changed to 1.2 MPa. I would like to ask everyone how many tons of steam this boiler can produce per hour (I really don’t know how to make the conversion)
This calculation is actually quite simple; you need to perform it using parameters such as the feedwater temperature, the temperatures of the primary and secondary air, the boiler’s thermal efficiency, and the blowdown rate. The table below is a simple calculation table; when only the parameters change, the amount of gas produced changes very little. | Serial No. | Item | Unit | Data |
| --- | --- | --- | --- |
| 1 | Rated evaporation capacity | t/h | 6565 |
| 2 | Rated pressure | MPa | 1.61.2 |
| 3 | Rated steam temperature | °C | 205193 |
| 4 | Feedwater temperature | °C | 2020 |
| 5 | Primary air preheating temperature | °C | 150150 |
| 6 | Secondary air preheating temperature | °C | 150150 |
| 7 | Flue gas temperature | °C | 150150 |
| 8 | Thermal efficiency | % | 90%90% |
| 9 | Boiler blowdown rate | % | 2%2% |
| 10 | Heat loss due to incomplete combustion | % | 4%4% |
| 11 | Enthalpy of superheated steam Hish, skJ/kg | | 2,796.52,790.3 |
| 12 | Enthalpy of saturated water His,w kJ/kg | | 872.1815.0 |
| 13 | Enthalpy of feedwater Hif,w kJ/kg | | 85.585.1 |
| 14 | Heat output of the boiler Q kJ/h | | 1.77E+081.77E+08 MW49.23349.108 |
| 15 | Calculated fuel consumption | w kg/h | 9,4199,395 |
| | Smoke gas calculation basis | Vt/h | 9.429.39 |
| 16 | Total fuel consumption | kg/h | 9,8119,786 |
| | t/h | 9.819.79 |
| 17 | Gas production rate per ton of raw coal | t steam/t coal | 6.62506.6419 |
| 18 | Gas production rate per ton of standard coal | t steam/tce | 9.27499.2986 |
As can be seen from the data in the table, the variation in coal consumption is extremely small, only about 20 kg. The parameters of the steam produced are not much changed; if it is saturated steam, the gas production volume of such industrial boilers will not vary significantly. However, this is different if superheated steam is produced. It is necessary to provide the parameters of the steam produced by the boiler in the past as well as the parameters required now in order to make accurate calculations.
| --- | --- | --- | --- |
| 1 | Rated evaporation capacity | t/h | 6565 |
| 2 | Rated pressure | MPa | 1.61.2 |
| 3 | Rated steam temperature | °C | 205193 |
| 4 | Feedwater temperature | °C | 2020 |
| 5 | Primary air preheating temperature | °C | 150150 |
| 6 | Secondary air preheating temperature | °C | 150150 |
| 7 | Flue gas temperature | °C | 150150 |
| 8 | Thermal efficiency | % | 90%90% |
| 9 | Boiler blowdown rate | % | 2%2% |
| 10 | Heat loss due to incomplete combustion | % | 4%4% |
| 11 | Enthalpy of superheated steam Hish, skJ/kg | | 2,796.52,790.3 |
| 12 | Enthalpy of saturated water His,w kJ/kg | | 872.1815.0 |
| 13 | Enthalpy of feedwater Hif,w kJ/kg | | 85.585.1 |
| 14 | Heat output of the boiler Q kJ/h | | 1.77E+081.77E+08 MW49.23349.108 |
| 15 | Calculated fuel consumption | w kg/h | 9,4199,395 |
| | Smoke gas calculation basis | Vt/h | 9.429.39 |
| 16 | Total fuel consumption | kg/h | 9,8119,786 |
| | t/h | 9.819.79 |
| 17 | Gas production rate per ton of raw coal | t steam/t coal | 6.62506.6419 |
| 18 | Gas production rate per ton of standard coal | t steam/tce | 9.27499.2986 |
As can be seen from the data in the table, the variation in coal consumption is extremely small, only about 20 kg. The parameters of the steam produced are not much changed; if it is saturated steam, the gas production volume of such industrial boilers will not vary significantly. However, this is different if superheated steam is produced. It is necessary to provide the parameters of the steam produced by the boiler in the past as well as the parameters required now in order to make accurate calculations.
Perhaps my question wasn’t expressed clearly. What I mean is: for a saturated steam boiler with a gas generation capacity of 65 t/h and a gas generation pressure of 1.6 MPa, under unchanged other conditions, by how much can the hourly gas generation capacity increase when the gas generation pressure is reduced to 1.2 MPa?
When the steam generation rate is 65 t/h, the coal consumption is 9,419 kg/h for saturated steam at 1.6 MPa, and 9,395 kg/h for saturated steam at 1.2 MPa. If you replace the coal consumption value of 9,395 with 9,419, can’t you still calculate the steam generation rate? What? Can’t you do this conversion?