Page 385 - Air Pollution Control Engineering

08_chap_wang.qxd 05/05/2004 4:26 pm Page 360
360 Lawrence K. Wang et al.

1. Reported destruction efficiency, DE (%)
reported
2. Temperature of the emission stream entering the incinerator:
if no heat recovery, T ºF
e
if a heat exchanger employed, T (ºF)
he
3. Combustion temperature, T (ºF)
c
4. Residence time, t (s)
r
5. Maximum emission stream flow rate, Q (scfm)
e
6. Fuel heating value, h (Btu/lb)
f
3
7. Combustion chamber volume, V (ft )
c
8. Flue gas flow rate, Q (scfm)
fg
5.3. Decision for Rebuilding, Purchasing New or Used Incinerators
Technical innovations have changed the landscape of the incinerator market.
These advances have dramatically impacted the economics of VOC control and cre-
ated new options for meeting future clean air regulations. The durability of inciner-
ators themselves contributes to this picture. The physical structure of an incinerator
unit may have years of remaining life, but its operating efficiency may no longer
meet current needs. What does a plant do when faced with changing regulations or
process expansion?
There is no easy answer and multiple options need to be explored. For example, many
of the new incinerator innovations can be retrofitted into existing units. This means a plant
engineer may be able to improve the VOC destruction, thermal efficiency, and capacity of
the existing system while lowering its operating costs and expanding process flexibility.
In addition, the growing popularity of incinerators in industry is creating an increasing
supply of used systems for sale. Often these units can be cost-effectively upgraded to
increase VOC destruction efficiency or add needed capacity.
Further fueling the changing face of emission control options, the price of new
incinerators has dropped significantly in recent years. Two typical examples on how
to make decisions on rebuilding, purchasing new, or purchasing used incinerators have
been presented in a recent technical article (23). In case the plant manager decides to
purchase new process equipment, thermal incinerators (thermal oxidizers) are commer-
cially available (24,25). More technical information on thermal oxidizers is available
elsewhere (28–31).
5.4. Environmental Liabilities

The risk management process provides a framework for managing environmental
liabilities. It is composed of the identification, quantification, and ultimate treatment of
loss exposures. Indelicato (26) has outlined several strategies than can be used singularly
or in combination for the risk management to accomplish two objectives: (1) to control
losses and (2) to minimize the financial impacts resulting from the loss.

6. DESIGN EXAMPLES
Example 1

Develop a calculation sheet for thermal incineration (4) before performing design and
technical calculations.