c) The quantity of makeup water is calculated:

M = (%M/100) x F

or (28/100) X 5.3 kg/s (42,105 lb/hr)

M = 1.5 kg/s (11,789 lb/hr)

d) The quantity of condensate return is calculated:

EQUATION

R = F - M = 5.3 1.5 = 3.8 kg/s (30,316 lb/hr)

(13)

3-1.6.3

condensate returned represents the combined loss from the system of both steam and

condensate. These losses may result from leakage of steam, consumption of steam by

the process equipment, leakage of condensate, or deliberate discharge of contaminated

condensate. The total water loss can be calculated:

EQUATION

L=ER

(14)

where

L = total steam and condensate losses, kg/s (lb/hr)

E = steam generated, kg/s (lb/hr)

R = condensate return, kg/s (lb/hr)

EXAMPLE 3-3:

a) The steam losses from the boiler described in Examples 3-1 and 3-2 can

be calculated:

EQUATION

L = E - R = 5.0 3.8 = 1.2 kg/s (9684 lb/hr)

(15)

b) This relationship and the information from the previous examples are

presented in Figure 3-9.

3-1.6.4

evaluating boiler system efficiency can be developed by monitoring the system's water

conductivity values, measuring the quantity of steam generated, and performing the

required calculations after a regularly scheduled interval of time. An increase in steam

loss may indicate a new leak, a size increase in existing leaks, a new consumption of

steam, or condensate losses. Additionally, calculations of boiler system efficiency can

provide a good basis for estimating savings in steam cost resulting from maintenance

efforts to reduce steam and condensate losses.

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