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PROCEDURE NO. PTD-DGS-112 PAGE OF 1 52 PROCESS TECHNOLOGY PROCEDURES PREPARED B

PROCEDURE NO. PTD-DGS-112 PAGE OF 1 52 PROCESS TECHNOLOGY PROCEDURES PREPARED BY W. McMechen DATE 13 November 2003 DEPARTMENT: PROCESS ENGINEERING APPROVED BY A. Bourji SUBJECT: WINTERIZATION DESIGN GUIDE REVISION DATE 30 June 2004 REV. 2 Table of Contents 1.0 SCOPE.............................................................................................................................1 2.0 RESPONSIBILITIES........................................................................................................3 3.0 DEFINITIONS..................................................................................................................5 4.0 PROCEDURE..................................................................................................................7 4.1 General Information............................................................................................7 4.2 Protection Methods.............................................................................................8 4.3 Evaluation Considerations...............................................................................10 5.0 HEAT TRACING............................................................................................................13 5.1 General...............................................................................................................13 5.2 Steam Tracing...................................................................................................15 5.3 Electric Tracing.................................................................................................19 6.0 PROTECTION OF PIPING............................................................................................20 6.1 Underground Piping.........................................................................................21 6.2 Process Piping Above Grade...........................................................................21 6.2.1 Protection Guidelines............................................................................21 6.2.2 Protection with Heat Tracing and Insulation.........................................22 6.2.3 Protection with Other Methods.............................................................29 6.3 Water Piping......................................................................................................30 6.3.1 Protection Guidelines............................................................................30 6.4 Utility Piping......................................................................................................36 6.5 Fire Water systems...........................................................................................37 7.0 PROTECTION OF EQUIPMENT...................................................................................38 7.1 Tanks..................................................................................................................38 7.2 Vessels...............................................................................................................39 7.3 Pumps.................................................................................................................41 7.4 Air Cooled Heat Exchangers............................................................................43 7.5 Machinery...........................................................................................................44 8.0 PROTECTION OF INSTRUMENTS..............................................................................46 8.1 General Requirements......................................................................................46 8.2 Specific Requirements.....................................................................................48 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 1 52 1.0 SCOPE This design guide covers minimum general requirements for design of cold weather protection for piping, equipment and instruments. Specific requirements for protection devices or installation details are not covered in this guide. The purpose of winterization is to provide a facility that is both operable and maintainable during extended periods of low ambient temperature, giving due consideration to the design 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 2 52 of equipment and piping systems such that low temperatures do not impair performance or operation. The facility should be designed to protect against the following conditions: • Freezing of process and utility fluids • Congealing of viscous fluids • Pour point suppression • Condensation that may lead to corrosive compounds • Any undesirable separation that may occur at low ambient temperatures • Start-up problems under severe winter conditions 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 3 52 • Hydrate formation 2.0 RESPONSIBILITIES The Process Engineer establishes requirements with the Client for winterizing and the minimum design and maximum ambient temperatures to be used in designing the piping, instrumentation, and equipment. The Process Engineer also determines where thermal insulation is required and describes the details on the P&IDs and line lists for piping, instrumentation and equipment. 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 4 52 The Mechanical Engineer prepares the specifications for insulation materials and thickness, coordinates the winterizing/insulation requirements with the equipment suppliers and reviews the P&IDs/vendor drawings to ensure the correct depiction of equipment requirements. The Control Systems Engineer reviews the P&IDs and instrument drawings to ensure the correct depiction of the instrument winterization/insulation requirements. 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 5 52 Piping Design establishes the configuration details for winterizing pipe, indicates the insulation and winterizing requirements on its drawings, and assists in the final review of winterizing and insulation design. 3.0 DEFINITIONS Process. The term “Process” is used to denote the department, group or engineer who develops the PFDs and P&IDs. The term ”Process” could refer to Process Engineers, Process Systems Engineers or Mechanical Systems Engineers. 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 6 52 Mechanical. The term “Mechanical’ is used to denote the department, group or engineer who handles the static and rotating equipment. Control Systems. The term “Control Systems” is used to denote the department, group or engineer who handles the instrumentation. The words “Instrumentation or Instrument” are often substituted for “Control Systems”. Piping. The term “Piping” is used to denote the department, group or engineer who handles the design of the piping as will as tie-in locations. 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 7 52 4.0 PROCEDURE 4.1 General Information The requirement for winterization and the minimum design ambient temperature should be established with the client before winterizing or insulation is applied. The project specified thermal insulation criteria and specifications should be obtained before insulation thickness requirements for heat traced lines and equipment are added to the line summary or equipment descriptions. In absence of project specified insulation tables for 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 8 52 heat tracing applications use the insulation tables for heat conservation provided in the Line List Input Design Guide, PTD-DGS-128. 4.2 Protection Methods The following methods should be considered for cold weather protection of piping, equipment, and instruments: a. Draining of piping and equipment when not in service. 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 9 52 b. Recirculation and bypass lines to maintain partial circulation. c. Agitation or intermittent flow through idle piping and equipment. d. Sheltering. e. Insulating to retain heat. f. Flushing, purging, or displacing process fluid with a nonfreezing fluid. 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 10 52 g. Heat tracing to apply heat and insulating to retain it. h. Heaters. i. Using antifreeze solutions or diluting streams with lighter, nonfreezing fluids. 4.3 Evaluation Considerations 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 11 52 a. Sealing, purging or displacing process fluid with nonfreezing fluid or heat tracing have significantly higher initial, operating, and maintenance costs than other alternative winterization methods. b. Draining of piping, intermittent flow, sealing, purging, or displacing process fluid with nonfreezing fluid require coordination with operational procedures and careful selection of block valve location. Block valves should be accessible, and they should eliminate dead legs or permit lines to be self-draining. Additionally, they should be located so that idle pipe or equipment can be fully drained or displaced. 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 12 52 c. Recirculation lines maintain back-flow through spare pumps for cold weather protection or to keep the temperature of the pump at a certain level due to mechanical requirements. d. In order to protect piping when the connected equipment is isolated, a minimum-flow continuous bypass line can be installed around the equipment. e. Insulation is an economical method for cold weather protection. Adding heat tracing increases the degree of protection. 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 13 52 f. Insulation without heat tracing requires the use of non-wetting insulation, cellular glass or perlite 5.0 HEAT TRACING 5.1 General 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 14 52 5..1.1 For process systems that carry fluids with critical temperatures (pour point, freeze point, flow point) above 50°C, the heat tracing system should have sufficient capability to maintain the fluid 30°C above the critical temperature. 5..1.2 For process systems that carry fluids with critical temperatures (pour point, freeze point, flow point) above the design cold weather temperature, but less than 50°C, the heat tracing system should have sufficient capability to maintain the fluid temperature 5-15°C above the critical temperature. 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 15 52 5..1.3 The heat tracing system should have the capability to heat a line sufficiently within a twelve-hour period to permit initial circulation after the line has cooled to the winter design temperature, if steam tracing is used. Electrical tracing systems will not need to meet this requirement unless otherwise specified. 5.2 Steam Tracing Note that steam tracing is not temperature controlled and, if used exclusively for winterization, should be turned off once the threat of freeze is over. 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 16 52 5.2.1 Steam tracing systems should be designed in accordance with specifications issued for a particular project. 5.2.2 In systems where the process fluid is heat sensitive, volatile, or corrosive at the tracer temperature, the tracers should be separated from the pipe by approximately ½" with insulation tape wrapped around the tracer or with insulation blocks at approximately 2-foot intervals. 5.2.3 Steam tracing systems should have the capability of raising the temperature of the stagnant fluid from the specified project cold weather design temperature, to either 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 17 52 30°C (paragraph 5.1.1) or 15°C (paragraph 5.1.2) above the critical temperature in a twelve-hour period. 5.2.4 The use of heat conductive cement or steam-jacketed lines should be considered where applicable. Heat conductive cement eliminates hot spots and should be considered. 5.2.5 Depending on the process temperature, the design should consider piping steam- out and associated temperatures if they are higher than the normal operating level. 5.2.6 Selection of design steam pressure should consider the following factors: 196692140.doc WINTERIZATION DESIGN GUIDE PROCEDURE NO. PTD-DGS-112 REV. 2 DATE 30 June 04 PAGE OF 18 52 a. The stability of the process fluid at steam tracing uploads/Management/ winterization-design-guide.pdf