If a boiler is rated at 30,000 lb/hr with a 5% blowdown loss, what is the minimum size feed water pump required to supply this boiler in gal/hr?

If a boiler is rated at 30,000 lb/hr with a 5% blowdown loss, what is the minimum size feed water pump required to supply this boiler in gal/hr?

• A. 2500 gal/hr
• B. 3795 gal/hr
• C. 4000 gal/hr
• D. 5000 gal/hr

Answer: (B)

To determine the minimum size of the feed water pump required for a boiler rated at 30,000 lb/hr with a 5% blowdown loss, it is essential to calculate the total water input needed to account for that loss. First, understand that the blowdown loss represents a portion of the water that is removed from the boiler to maintain water quality and is not returned to the feed water system. If the blowdown loss is 5%, it indicates that for every 100 units of water, 5 units are lost, meaning 95 units remain. To calculate the total required input of water, you need to figure out the amount of water that has to be supplied to the boiler, which includes both the steam produced and the blowdown loss. This can be formulated as: Total water needed = Boiler rating + Blowdown loss The blowdown loss can be calculated as 5% of the boiler’s output. Here’s how this works: 1. Calculate the blowdown loss: \[ \text{Blowdown loss} = 30,000 \, \text{lb/hr} \times 0.05 = 1,500 \, \text{lb/hr} \] 2. Now

To determine the minimum size of the feed water pump required for a boiler rated at 30,000 lb/hr with a 5% blowdown loss, it is essential to calculate the total water input needed to account for that loss.

First, understand that the blowdown loss represents a portion of the water that is removed from the boiler to maintain water quality and is not returned to the feed water system. If the blowdown loss is 5%, it indicates that for every 100 units of water, 5 units are lost, meaning 95 units remain.

To calculate the total required input of water, you need to figure out the amount of water that has to be supplied to the boiler, which includes both the steam produced and the blowdown loss. This can be formulated as:

Total water needed = Boiler rating + Blowdown loss

The blowdown loss can be calculated as 5% of the boiler’s output. Here’s how this works:

1. Calculate the blowdown loss:

[

\text{Blowdown loss} = 30,000 , \text{lb/hr} \times 0.05 = 1,500 , \text{lb/hr}

]

2. Now