(54f) Which One of These Usual Suspects Is the Culprit? High-Quality Distributor or High-Quality Packing?

In a chemical plant, a new unit (K3) was built as a carbon copy of an existing one (K2, sister plant). That existing unit, K2, was itself a copy of another unit (K1, mother plant). The main distillation columns in all the units were equipped with high-capacity structured packing and high-performance distributors. The columns were working nicely and meeting strict product purity specs, except the new column in K3. The product was not pure enough and caused loss of product and a daily negative financial impact. This forced K3 to be operated at minimum rates to mitigate the losses.

The plant went through several shutdowns, multiple testing, changing column internals and operating parameters. However, the shortfall continued to exist.

This presentation covers the step-by-step troubleshooting activities to follow the leads of usual suspects, packing vs. distributor, which reveals a lot more than just answering the questions below and gets the column product back to specification and even exceed all other units, K2 and K3. At 100% rates, the overhead product losses went from >4% to <0.5% whereas the bottom impurity content reduced from >.05% to <0.004%. There was a significant reduction in utility usage as a result of relaxed operating parameters.

So, the question is “Which of the Two Usual Suspects Was the Culprit? High-Quality Distributor or High-Quality Packing?”- It took 6 shutdowns amounting to 120 days within 4 years and a ton of product loss to eventually find the guilty one.