CleaverBrooks CBEX-DE, Эксплуатация и обслуживание

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Introduction
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CBEX -DE
The CBEX-DE is a 2-pass dry-back design. The flame originates in the furnace. As the combustion gases travel
down the furnace and through the firetubes, heat from the flame and combustion gases is transferred to the
water to generate steam.
For lower emissions the CBEX-DE firetube boiler line is designed to incorporate induced Flue Gas Recirculation
(FGR). FGR may be used when firing either natural gas and/or light oil.
The FGR system mixes a portion of the relatively cool flue gas from the exit of the second-pass tubes with the
incoming combustion air to reduce the furnace flame temperature, thereby reducing NOx emissions. In this
approach, the combustion air fan handles both the combustion air and the recirculated flue gases. Carbon mon-
oxide (CO) emissions also tend to be lower due to increased turbulence caused by the addition of the flue gases
into the combustion air stream.
The low emission design can affect the selection of the combustion air fan, motor, burner, and other components.
Several different system configurations are available, depending on the requirements for NOx emissions and the
fuels used. All systems use similar primary components, but fan and motor sizes as well as the FGR damper may
differ.
Installation should conform to state and local codes. Prior to installation, the proper authorities having jurisdic-
tion are to be consulted, permits obtained, etc.
CBEX-DE boilers offer compliance with multiple insurers’ requirements. Equipment provided may vary depending
on insurance.
Steam boilers are built for a specific design pressure, which is the pressure used in calculating the minimum per-
missible thickness or physical characteristics of the pressure vessel components. Typically, the safety valves are
set at or below design pressure.
Care taken in placing the pressure vessel into initial service is vital. The waterside of new boilers and new or
remodeled steam or hot water systems may contain oil, grease, or other foreign matter. Waterside care will con-
tinue to be important throughout the lifetime of the boiler. A boilout method for new boilers, as well as general
waterside care information, can be found in Chapter 2.
1.1.1 — Construction
Steam boilers designed for 15 psig and hot water boilers designed for 250º F at 125 psi or less are constructed
in accordance with Section IV, Heating Boilers, of ASME Code.
Steam boilers designed for operating pressures exceeding 15 psig are constructed in accordance with Section I,
Power Boilers, of the ASME Code. Hot water boilers designed for operating temperatures above 250º F or 125
psi are likewise built to Section I of the ASME Code.