Troubleshooting mechanical problems

John J. France of Sulzer Chemtech USA Inc. provided expert information on troubleshooting distillation columns to the Rio Grand Chapter of AIChE. Checklists were provided for troubleshooting mechanical problems based on considerable successful field experience. This portion of the presentation is presented here with permission. 

Catalyst circulation can also be limited by mechanical problems with the slide/plug valves. They may have limited travel or will not open fully. This is indicated by the lack of response when an adjustment is made. The differential pressure and the flow will not change. Troubleshooting the valves is a function of the valve design and the vendor will supply troubleshooting information,... 

If you were fo divide all refinery knowledge into three equal parts, fluid catalytic cracking unit (FCCU) technology would encompass one full portion. Not only is an FCCU the economic heart of most refineries, but advances in catalyst and mechanical design constantly expand the scope of the troubleshooter s problem. 

Troubleshooting and Diagnostics (mechanical and non-mechanical problems, determination of probable problem cause, mechanic s responsibilities.)... 

Thermal analysis (TA) consists of a family of analytical techniques in which a property of the sample is monitored against time or temperature while the temperature of the sample is programmed. The properties include weight, dimension, energy take-up, differential temperature, dielectric constant, mechanical modulus, evolved gases, and other, less common attributes. The application of thermal analysis is widespread within the polymer and elastomer industries. Thermal analyzers are used to qualify a material for fitness of use and to troubleshoot processing problems. Thermal analysis consists of three primary techniques that may be used individually or in combination ... 

Problems with the mechanics of a procedure can involve an improperly diluted sample (perhaps manifested by an absorbance reading that is greater than specified or expected), an obstruction in the sample or reference beam, an improperly aligned source or mirror, the incomplete programming of a scan, or improper or inappropriate software entry. In these cases, the operator will need to carefully examine his or her technique or procedure, or instrumental parameters, such as the optical path, perhaps with the help of the instrument troubleshooting guide, to solve the problem. 

With its wealth of information and rare focus solely on the subject, this book provides practical tools to help readers better understand these and other problems and then develop optimal solutions and strategies. It discusses mechanisms of organic acid antimicrobial action and facilitates troubleshooting techniques regarding problems with preservatives and microorganisms. It also shows how to predict the effectiveness of a preservation method or application. 

Discrepancies in performance may be caused by deviations in physical properties of fluids, flow rates, inlet temperatures, mechanical construction of the equipment, or by problems caused during the installation of the equipment. The troubleshooter should first check to see that compositions, flows, temperatures, and physical properties agree with those specified for design. He should then examine the equipment drawings to determine if the problem could lie in the manner in which the equipment was constructed, or in the manner in which the equipment has been installed. After these basic items have been reviewed, the checklist below outlines some questions that should be raised. 

Each of these will be discussed in further detail below. Other troubleshooting areas, not discussed, include mechanical failures, damages from fire and explosion, and problems with auxiliaries. Kister Lieberman, and Saletan provide details on troubleshooting. 

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