Category: TroubleShooting

Evaluation of Paint Booth

A manufacturer wanted to expand their operation of the paint booth. The paint booth’s capacity was limited by the emissions of Hexavalent Chromium.

The existing paint boot had a filtration system to collect the overspray as a primary control device. A previous consultant suggested adding a water scrubber as a secondary control device. They proposed to monitor the discharge water stream to show that the scrubber was in proper operation.

Adding a scrubber as a secondary control device is not an efficient use of control technology. Further, measuring the concentration in the water discharge stream does not effectively measure the control. If the filtration system collected more materials, then the hexavalent chrome going to the scrubber would be reduced and the concentration in the discharge would be less.

I decided to look at the entire process. The paint in the spray booth was a mixture of 3 component paint mixture, which only one has hexavalent chrome.  The Hexavalent Chrome emissions were calculated by assuming all of the Hexavalent Chrome that was in the paint were emitted.

The procedure called for mixing the paint for 30 minutes prior to spraying. I had an independent laboratory test the mixture after 30 minutes. The hexavalent chromium in the combine mixture was reduced to Tri-valent Chrome and considerably less before the mixing of the 3 components. The manufacturer was able to increase the production without adding additional air pollution control devices.

Roof Vent Overflow

A manufacturing company had filter press that had too much back pressure and occasionally when the filters were back washed the vents spilled materials on to the roof. The company was not able isolate this to a specific product or process. The spillage onto the roof caused rusting to the sheet metal. All other parts of the process were performing according to design conditions. I designed a trough to collect any spillage from the vents and piped them to the process sewer.

HPCH Yield Improvement

A company manufactured High Purity Calcium Hydroxide that had low yields. The annual capacity of the plant was relatively low at less than 10 tons per year. I installed measuring devices to measure rinse water flows and had samples analyzed for product. This had accounted for a portion of the product loss. Steps were taken to reduce this loss. In addition, there were losses associated with the rotary filter and material handling that were identified and corrected. Because of the low annual production and the high density of the small spills of material on the process floor had a significant impact in yields. Steps were made to prevent this material from spilling or reworking the spilled material.  After the measures were taken the yields were back up to design specifications.

Reestablishment of Clear Water Sewer

A chemical manufacturing plant had two sewer systems, a storm sewer and a process sewer that were in the past combined into a single sewer. Years later, added development caused the combine flow of the sewer exceed the design capacity of the treatment system during some storm events.

An investigation of the feasibility of separating at least a portion of the storm sewer was conducted. As no as-built copies of the complete sewer system were available, each manhole and source had to be mapped out.

After a complete update of the sewer maps, it was discovered that a neighboring property that was allowed to tie into the system also recently built a large warehouse that tied into the system. It was this stream, that was diverted to a new storm sewer system.