Problem
A manufacturer of insulation films for the electronics industry
needed to evaluate the capabilities of four existing oxidizers that
treated emissions from its coating lines. The company was concerned
that, due to oxidizer deficiencies, it would not meet regulatory
requirements. The oxidizers had been manufactured by two different
companies. One of them was no longer in business; the other was
unable to provide an adequate solution. The customer needed an
experienced engineering company that could accurately identify the
oxidizers' deficiencies and provide quality repairs.
Action
After evaluating the service capabilities of several equipment
manufacturers and engineering consultants, the company chose the
full-service solution of Anguil Environmental Systems, Inc.
Anguil's thorough preventive maintenance evaluation of the four
oxidizers provided detailed recommendations to improve the
oxidizers' performance. The most urgent recommendation saved the
company thousands of dollars in operating costs and put the company
in compliance.
Solution
Anguil's rigorous 75-point preventive maintenance evaluation
(PME) discovered minor problems with three of the units and a major
problem with the largest oxidizer, a 13,500 SCFM catalytic
oxidizer. Anguil's recommendations for the three smaller oxidizers
greatly improved their safety and performance. Many of the
cost-saving suggestions were easily performed by the plant's
in-house maintenance staff. The larger 13,500 SCFM oxidizer,
however, required more intensive application engineering and a
comprehensive air pollution control solution.
The 13,500 oxidizer uses a primary and secondary
heat exchanger. The primary heat exchanger recovers energy from the
combustion chamber exhaust and transfers it to the incoming process
air stream to reduce fuel consumption. The secondary heat exchanger
recovers additional energy from the primary heat exchanger outlet
flow and uses this energy to preheat an air source used in the
process. In this case, the secondary heat exchanger is integral to
the plant's coating process; it is used to heat the tower dryer of
the AISCO coating machine. The plant engineers had noticed a steady
decline in the heat available from the oxidizer and secondary heat
exchanger. By the time of Anguil's investigation, the oxidizer took
up to six hours to sufficiently heat the coater before production
could begin. During the six hours of warm-up, the oxidizer had to
be supplied with natural gas. This tremendous fuel consumption led
to extremely high operating costs.
Anguil's internal inspection revealed major damage to the heat
exchanger. A third of the front tubes had separated from the bottom
plenum and deformed into the second row of tubes, effectively
blocking around 25% of flow through the remainder of the exchanger.
Anguil's evaluation also pinpointed several areas where the airflow
was bypassing the exchanger, traveling in the gaps between the
exchanger and the ceramic insulation and passing through tears in
the tubesheet and top plenum. The combination of bypass areas and
the tubesheet tears allowed solvent vapors to bypass the combustion
chamber, which greatly lowered the destruction efficiency of the
oxidizer.
Anguil performed a destruction efficiency test on the oxidizer
when the coated web used 100% toluene as a solvent. Under normal
conditions, an oxidizer of this type should have little difficulty
in attaining better than 98% destruction efficiency. Due to the
airflow bypassing the combustion chamber, the oxidizer was
achieving only 93.6% destruction efficiency and did not meet
regulatory emission requirements.
Replacing the oxidizer would have drastically interrupted the
customer's manufacturing schedule and resulted in capital cost
increases that were unacceptable. Anguil's solution, however,
eliminated any production disruptions by performing repairs and
design enhancements over several process downtimes. The first step
was to immediately replace both the primary and secondary heat
exchangers. Anguil designed, manufactured and installed replacement
exchangers for this oxidizer. The dismantling, removal and
replacement of the exchangers were performed over a three-day
weekend when the customer had a scheduled plant shutdown.
The replacement heat exchangers significantly improved the
performance of the 13,500 SCFM oxidizer. Previously, the oxidizer
had to be run for up to six hours to meet the necessary temperature
at a fuel cost estimate of $266/per startup. The process air
temperature required for the coating machine is now achieved in one
hour. The improved efficiency results in operating cost savings of
approximately $230 per startup and up to $30,000 annually. The
economic impact of the retrofitted heat exchangers went beyond fuel
savings; the improved start-up time has reduced plant downtime and
increased worker production. The new heat exchangers have also
improved the destruction efficiency of the oxidation system and put
the company in compliance.
Anguil's analysis detailed other cost saving suggestions for the
company, including:
- Ductwork adjustments for more efficient oxidizer operation
- Heat exchanger maintenance suggestions for all four
oxidizers
- Review of safety controls and upgrade recommendations
- Variable Frequency Drive for the fan on the largest oxidizer to
accommodate airflow changes more efficiently
- Burner maintenance suggestions
Anguil also performed airflow analysis of all processes. This
information will help the company plan for future growth with
additional coating lines.
The retrofitted system is currently exceeding the regulatory
requirements and providing an efficient heat source for the coating
lines. The Anguil service team's expert troubleshooting and quality
turnkey solution capabilities have led to another satisfied
customer.