The Boiler Blowdown Rate Calculator helps determine the amount of water that must be discharged (or "blown down") from a boiler to control the concentration of dissolved solids. Blowdown is essential to maintain boiler efficiency and prevent scale, corrosion, and other operational problems. The calculator enables operators to optimize the blowdown rate, ensuring efficient boiler operation without excessive water or energy waste.
Formula of Boiler Blowdown Rate Calculator
The blowdown rate is calculated using the following formula:
Where:
- Blowdown Rate (%) is the percentage of total water that needs to be discharged.
- Feedwater Rate is the amount of water fed into the boiler (kg or lbs per hour).
- Feedwater TDS refers to the total dissolved solids in the feedwater, measured in ppm.
- Boiler Water TDS refers to the total dissolved solids in the boiler water, also in ppm.
This calculation helps maintain the right balance between water quality and boiler performance, keeping TDS within safe limits.
General Reference Table for Boiler Blowdown Rates
Here is a general table that estimates blowdown rates for various boiler conditions:
| Boiler Size (kg/hr) | Feedwater TDS (ppm) | Boiler Water TDS (ppm) | Blowdown Rate (%) |
|---|---|---|---|
| 5000 | 100 | 3000 | 3.33 |
| 10000 | 200 | 4000 | 5.00 |
| 15000 | 150 | 4500 | 3.45 |
| 20000 | 100 | 5000 | 2.08 |
This table helps operators quickly assess approximate blowdown rates without the need for constant calculations.
Example of Boiler Blowdown Rate Calculator
Scenario:
A boiler has a feedwater rate of 10,000 kg/hr, with a feedwater TDS of 200 ppm and boiler water TDS of 4,000 ppm.
Step 1: Use the formula: Blowdown Rate (%) = (10,000 * 200) / (4,000 - 200)
Blowdown Rate (%) = 2,000,000 / 3,800
Blowdown Rate (%) ≈ 5.26%
The operator would need to blow down about 5.26% of the boiler water to maintain efficiency.
Most Common FAQs
Blowdown prevents the buildup of dissolved solids, which can cause scale and corrosion, leading to reduced efficiency and potential damage.
The frequency depends on boiler conditions, but regular monitoring of TDS levels ensures blowdown is perform as needed without excessive water loss.
Excessive blowdown wastes water and energy, increasing operating costs unnecessarily.