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This section provides an overview of typical heat exchanger applications, available industry technology and standards, and the Company’s normal degree of involvement in heat exchanger design and selection.
100 General Information Abstract This section provides an overview of typical heat exchanger applications, available industry technology and standards, and the Company’s normal degree of involvement in heat exchanger design and selection Chevron Corporation Contents Page 110 Types of Exchangers and Applications 100-2 120 Industry Codes and Practices 100-2 130 Company Practice 100-3 100-1 December 1989 100 General Information Heat Exchanger and Cooling Tower Manual 110 Types of Exchangers and Applications The type of exchanger used for a given service depends on process, safety and operating requirements, and economics Selection of the most economical heat exchanger in a given service includes the initial cost of the exchanger, installation costs, maintenance costs, incremental pumping and compression costs, and where applicable, utility system investment and energy requirements As an example, the initial cost of a water-cooled shell and tube heat exchanger will be much less than an air-cooled heat exchanger for the same service However, the cost of the cooling water supply, including makeup water, chemical treatment, blowdown disposal, the cooling tower and fans, water circulation pumps, and piping to and from the water-cooled exchanger, often more than offset the lower first cost of the water-cooled exchanger Operating and maintenance costs for water coolers are also more than for air coolers Air cooling is usually more economical than water cooling when the required process fluid outlet temperature is 20°F or more over the design ambient air temperature Specific air cooler types, and their applications and limitations, are discussed in Section 600 In most cases, a custom designed shell and tube heat exchanger will be the economical choice Specific varieties of shell and tube exchangers, and their applications and limitations, are discussed in Section 400 Pre-engineered double pipe or small multitube hairpin heat exchangers compete with custom designed shell and tube exchangers and are usually economical when the required heat transfer surface area is less than about 1000 square feet Information on small pre-engineered exchangers is given in Section 400 Plate and frame heat exchangers may be economical where weight and space are highly valued, alloy material is required, pressures and temperatures are moderate (less than 200 psig and 250°F), and fluids are compatible with rubber gaskets Titanium plate and frame exchangers on offshore platforms in sea water/fresh water service are appropriate applications 120 Industry Codes and Practices The Company uses Heat Transfer Research Inc (HTRI) technology, supplemented by Company experience, for design and evaluation of thermal and hydraulic performance of heat exchangers HTRI conducts large scale tests of heat exchangers and incorporates the results into reports and computer programs HTRI has tested extensively shell and tube exchangers in boiling, condensing and single phase service, and completed limited testing of air coolers and plate and frame exchangers HTRI information is contract confidential and should not be disclosed outside of the Company Mechanical design of exchangers is based on standards developed by the American Society of Mechanical Engineers (ASME), Tubular Exchanger Manufacturers Association (TEMA), American Petroleum Institute (API), and Chevron December 1989 100-2 Chevron Corporation Heat Exchanger and Cooling Tower Manual 100 General Information ASME covers mechanical design of pressure vessel components (shells, channels, tubesheets, headers and some aspects of large flanges), and imposes restrictions on piping, instrumentation and inspection of steam boilers TEMA addresses shell and tube heat exchangers only, and covers nomenclature, fabrication tolerances, standard tube sizes, standard clearances, minimum plate thickness, and minimum tie rod requirements TEMA also provides tubesheet design rules that differ from ASME tubesheet design rules TEMA tubesheet rules are used for most shell and tube exchangers ASME tubesheet rules are used for stayed fixed tubesheet steam boilers, and air cooler headers API standards address mechanical design criteria of shell and tube exchangers, and air-cooled exchangers There are no industry standards for double pipe, multitube hairpin or plate and frame heat exchangers Fouling, corrosion, tube vibration, leak tightness of flanges, and safe design for tube rupture pressure transients are also discussed in this manual because the subjects are beyond the scope of industry standards (See Sections 200, 300 and 500.) 130 Company Practice Company practices vary Some locations normally specify all geometric parameters that affect thermal and hydraulic performance of shell and tube exchangers, with due consideration for fouling, corrosion, tube vibration, and maintainability Mechanical design is then left to the manufacturer, subject to the Company’s specified criteria and standards Other locations only specify the fluid streams, flow rates, and desired thermal performance They rely on Vendors to the mechanical and thermal design, and have reported satisfactory results Experience with shell and tube exchanger manufacturers also varies Some facilities have experienced problems with manufacturers’ designs for controlling tube vibration, fouling, corrosion, and thermal and hydraulic performance, whereas other locations routinely leave these design considerations to the manufacturer and experience no problems Thermal, hydraulic, and mechanical design of air coolers are usually completed by the manufacturer, subject to the Company’s specified criteria and standards Air coolers are used to condense and cool low viscosity fluids Vendors have adequate expertise in these services, and in air side design, including fan design, hub seals, tip seals, auto-variable blade control, etc If fouling is a potential problem, the Company must take responsibility for it and advise the Vendor how to control it Tube vibration is not a problem in air coolers Double pipe and small multitube hairpin exchangers are pre-engineered and have proprietary components They are preferred for small duty, low viscosity, single phase services The Company normally selects specific models from catalog information Chevron Corporation 100-3 December 1989 ...100 General Information Heat Exchanger and Cooling Tower Manual 110 Types of Exchangers and Applications... Chevron December 1989 100-2 Chevron Corporation Heat Exchanger and Cooling Tower Manual 100 General Information ASME covers mechanical design of pressure vessel components (shells, channels, tubesheets,... phase service, and completed limited testing of air coolers and plate and frame exchangers HTRI information is contract confidential and should not be disclosed outside of the Company Mechanical