Chemical Processing - November 2007 - (Page 36)

At one renery, six heat exchangers in a catalytic cracker recovery unit’s refrigeration section required maintenance. They weren’t operating ef ciently; examination showed severe tube corrosion and pitting. Two of the six exchangers needed complete retubings due to age and damage over time. The four remaining exchangers had only been operating for three years but still had telltale wear and tear, corrosion and pitting. Re nery management opted to apply coatings to all six exchangers to prevent further damage and to decrease fouling from sulfate-reducing bacteria. By coating all the equipment, ongoing preventive maintenance would suf ce to reduce stoppages, repairs, replacements and the need for any retubings — and the unit would see better performance from the equipment in the refrigeration section. Once the tubes were coated, the pressure performance stabilized. After retubing and coating, the coolant uid pressure in the two older heat exchangers dropped 10% from its previous 230 psi to within a steady range of 190 to 200 psi. The additional cooling eliminated all gas recycling and kept the unit at a 96% recovery rate, even in the hottest summer months, which amounts to an extra 1,000-bbl/d output. In contrast, the regular and long-duration cleaning cycles previously required caused lost production of 10,000 bbl/d. During their rst three years of “bare” pipe service, the four younger exchangers experienced an increase in pressure drop of 15 psi per year. Once the tubes were coated, the pressure performance stabilized. The re nery expects a 10-year minimum coating life for the exchangers, given some minor tubesheet touchups during maintenance periods. Af©2007 Rotex, Inc. Dry Screening Reaches New Heights The new APEX™ Screener from Rotex, Inc. is the smart solution for dry screening. The APEX delivers higher productivity and lower operating costs with the same efficiency and gyratory-reciprocating motion as the ROTEX® Screener. The new APEX increases up-time with side access doors that enable quick screen changes and cleaning by one person. To find out how the new APEX™ can increase your productivity, go to rotex.com/apex, or call 1-800-453-2321. www.chemicalprocessing.com http://www.smithco-eng.com http://www.smithco-eng.com http://www.smithco-eng.com http://rotex.com/apex http://rotex.com/apex http://rotex.com/apex http://www.chemicalprocessing.com

Table of Contents Feed for the Digital Edition of Chemical Processing - November 2007

Chemical Processing - November 2007 Contents From the Editor ChemicalProcessing.com Field Notes In Process Energy Saver Compliance Advisor PAT isn't Standing Pat Pursue the Perfect Plant Eliminate Exchanger Tubing Troubles Portable Conveyor Speeds Paint Production Process Puzzler Plant InSites Equipment & Services Product Spotlight/Classifieds Ad Index End Point

Chemical Processing - November 2007

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.