Strategies of Successful Distillation Equipment Revamps
Part 1: Determining Existing Distillation Equipment Capacities
Karl Kolmetz,
Daniel R Summers,
Dr. Wai Kiong Ng
Ryan Pitt
Westlake Group
Prepared for,
DISTILLATION 2005,
2005 Spring AIChE Meeting
Atlanta, Georgia,
April 10-14, 2005
Abstract
Successful unit operation revamps are those which have a high return on investment and low life cycle cost. Life cycle cost may include original capital, energy, operation, and maintenance cost over a typical life span of 10 years. For simplicity, some life cycle cost evaluations only include originally capital and energy cost. Distillation equipment is typically greater than 25% of total original capital cost and normally easiest to upgrade, as compared to rotating equipment.
Operational Plants have an original capital value per yearly production. For example, a new ethylene plant ISBL (inside the battery limit not including utilities and tank farms) might have a cost of US$ 400.00 per KTA (thousand tones per annum). A new 300 KTA ethylene plant might cost US$ 120,000,000.00. To be a cost effective revamp, the revamp should have less cost than the cost per ton of a new plant. With the proper selection of key items this can easily be accomplished, while also improving the life cycle cost.
Successful revamps generally have several key steps. The first step is a high load test to accurately determine the existing distillation equipment’s available capacity. The second step is to reconcile the data gathered in the high load test by a heat and material balance. This normally utilizes distillation software such as Pro II. The third step is with the reconciled data, rate the existing equipment verses it’s designed and target values. The fourth step is to select the key items to be upgraded with the maximum return on investment.
Planning and executing a high load test is a critical part of any successful revamp. It can identify and / or eliminate key equipment to be replaced or retained. Completion of an accurate high load test can simplify the steps, which follow, with the ultimate result – a successful revamp.