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.
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.
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 were calculated for the product costs but benefits of additional production capacity have not been provided.
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:
- Improved employee and facility productivity
- Improved product quality – including fewer reworks
- Improved public image through the elimination of the potential for chlorine emissions
- Achievement of sales and production goals
- Lower employee dust and ergonomic exposure levels
- Improved employee morale due to less manual handling, lower PPE requirements, and a cleaner workplace.