Case Study 11:
Chemical Substitution; Process Containment
Description of Operation
The company makes a proprietary product
that is used in the manufacturing of hybrid car batteries.
The product is manufactured at the nano-scale and has the
potential to become part of a significant growth industry given
the focus on reducing the USA’s
carbon-based energy dependence. The operation
prior to the intervention was a batched-based production process
involving nine steps which included manual handling and
potential employee nano-particle and ergonomic exposures at each
step.
Hazard Identification
In addition to the threat of inhalation of
nano-sized particulates the existing process used titanium
tetrachloride (TiCl4) as a catalyst. Titanium
tetrachloride is very irritating to the eyes, skin, mucous
membranes, and lungs. The use of TiCl4 required extra levels of
worker protection during the addition of the compound as well as
the use of pollution control equipment to scrub out the chlorine
gas from the production process before it was exhausted to the
atmosphere. In one case, a breakthrough of chlorine gas through
the scrubber system occurred, resulting in an air quality
violation and fine from the city.
In addition to the TiCl4 catalyst,
the old operation involved the manual transfer of lithium and
titanium compounds in a nine-step batch manufacturing process.
Each step involved the open-air transfer of product, creating
the potential for air and skin exposures as well as the
ergonomic hazards associated with the manual handling of
50-pound bags.
Hazard Intervention
The intervention involved redesign of the
production process, changing the way the final nano-product was
manufactured. As part of the intervention new
capital equipment was purchased that reengineered or enclosed
several of the existing process steps and as a result eliminated
seven manual handling operations. The
redesigned process now only requires manual handing at the
beginning and end of the production process. Modifying
the process also allowed for the elimination of TiCl4 for use as
a catalyst in the process thus eliminating the potential for
operator and community exposures to the material and its
decomposition products.
Impacts of the Intervention
In addition to the elimination of TiCl4 the
equipment containment also reduced exposure to the final nano-product
particulates at three points in the process. Previously,
operators were required to wear acid/dust respirators and now
are wearing simple air-purifying respiratory protection at the
first and last process steps, where loading of the raw materials
and unloading of the finish product occurs. By
changing the process the need to maintain and comply with air
quality permits associated with chlorine emissions was also
eliminated.
The redesign of the process also
contributed significant production-related advantages.
The new process has the capability of increasing the
production output by a factor of 10 in the same building space.
The production capacity increase has required the
doubling of the production staff running the new process,
resulting in a five-fold increase in product produced.
Financial Metrics
Financial metrics were calculated for the
product costs but benefits of additional production capacity
have not been provided.
Lessons Learned
By utilizing IH principles and practices of
elimination and product containment, the project was able to
achieve reductions in the potential for both employee and
community exposures to potentially hazardous substances. This
was accomplished by integrating IH concepts into a major process
redesign which significantly expanded production capacity.
This resulted in the benefit of increasing production
output and subsequent revenue opportunities as well as improving
employee health and welfare at several levels.
Specific benefits of the project
intervention included:
1. Improved employee and facility productivity
2. Improved product quality – including fewer reworks
3. Improved public image through the elimination of the
potential for chlorine emissions
4. Achievement of sales and production goals
5. Lower employee dust and ergonomic exposure levels
6. Improved employee morale due to less manual
handling, lower
PPE requirements,
and a cleaner workplace.
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