Cleaning of Process Equipment and Piping: A Complete How-to Manual

Process equipment and piping in chemical and petrochemical plants and petroleum refineries have to be cleaned periodically as part of normal maintenance operations to remove fouling that interferes with process flow, heat transfer, or other operations. Cleaning is also necessary to allow safe personnel entry prior to equipment inspection, repairs, or modifications. Most cleaning operations are expensive and time-consuming and need to be planned, budgeted, and carried out in a timely fashion to ensure minimum interference with normal process or maintenance operations. Certain process equipment and piping may also have to be cleaned prior to being put into service for the first time. Such pre-commission cleaning removes rust, dirt, and other debris that formed or entered during fabrication, shipment, or erection, and that are likely to cause damage after start-up. This manual, which was prepared under MTI Project 69, covers cleaning of process equipment and piping in chemical plants, petrochemical plants and petroleum refineries. Practical information and guidance is provided for plant engineers and operators who, from time to time, are charged with planning various cleaning operations that will be carried out either by in-house maintenance personnel or outside cleaning contractors. Sufficient information is given to enable the nonspecialist to either propose cleaning procedures or evaluate cleaning procedures proposed by others. The manual enumerates a multitude of factors that need to be considered before a cleaning operation is started, including timing, alternative methods, costs, manpower requirements, safety concerns, and waste disposal issues.

Table of Contents:
Section I: Reasons for Cleaning Process Equipment and Piping. Optimum cleaning cycles. Development of cleaning technology. Common cleaning methods. Special cleaning methods. Process equipment and piping most often cleaned. Process equipment and piping most often pre-commission cleaned. Section II: Causes of Fouling. Types of fouling. Fouling samples. General characteristics of fouling. Solubility of fouling. Chemical analysis of fouling. Section III: Planning a Cleaning Project. Assignment of responsibilities. Project definition. Timing of the cleaning project. Direct costs of the cleaning project. In-house versus contract cleaning. Soliciting competitive bids. Bid evaluation and contractor selection. Cleaning contract. Section IV: Managing a Cleaning Project. Preparation of detailed cleaning procedure. Permits, bonds and insurance. Site preparation. Safety measures. Monitoring and testing during the cleaning operation. Disposal of cleaning debris and spent cleaning chemicals. Preparation of final report. Section V: Cleaning Shell-and-Tube Heat Exchangers and Air Coolers. Pre-commission cleaning of heat exchangers. Heat exchanger fouling. Design criteria which minimize fouling. Operating practices which minimize fouling. Onstream mechanical cleaning systems. Design criteria which facilitate cleaning. Effect of heat exchanger metallurgy on cleaning options. Monitoring heat exchanger performance. Calculating the cost of heat exchanger fouling. General cleaning procedures for fouled heat exchangers. Specific cleaning procedures for fouled heat exchangers. Airside cleaning of air coolers. Section VI: Cleaning Fired Heaters. Pre-commission cleaning of fired heaters. Fouling of fired heaters. Design criteria which minimize fouling. Operating practices which minimize fouling. Design criteria which facilitate cleaning. Effect of tube metallurgy on cleaning options. Monitoring fired heater performance. Calculating the cost of fouling in fired heaters. General cleaning procedures for fouled tubes in fired heaters. Cleaning procedures for the inside of heater tubes. Cleaning procedures for the outside of heater tubes. Section VII: Cleaning Pressure Vessels. Pre-commission cleaning of pressure vessels. Pressure vessel fouling. Design criteria which minimize fouling. Operating practices which minimize fouling. Design criteria which facilitate cleaning. Effect of pressure vessel metallurgy on cleaning options. Monitoring pressure vessel fouling. General cleaning procedures for fouled pressure vessels. Vessel hazards. Specific cleaning procedures for fouled pressure vessels. Section VIII: Cleaning Storage Tanks. Pre-commission cleaning of storage tanks. Storage tank fouling. Design criteria which minimize fouling. Operating practices which minimize fouling. Design criteria which facilitate cleaning. Effect of storage tank metallurgy on cleaning options. Monitoring storage tank fouling.