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[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What are the minimum and maximum velocity limits in water service within heat exchangers for different tube materials?"
},
{
"role": "assistant",
"content": "According to the provided table, the minimum and maximum velocity limits in water service for different tube materials are:\n\n* Admiralty Brass: Minimum 3.0 ft/s (0.9 m/s), Maximum 8.0 ft/s (2.4 m/s)\n* Carbon Steel: Minimum 3.0 ft/s (0.9 m/s), Maximum 10.0 ft/s (3.0 m/s)\n* Cupro-Nickel 70/30: Minimum 3.0 ft/s (0.9 m/s), Maximum 10.0 ft/s (3.0 m/s)\n* Cupro-Nickel 90-10: Minimum 3.0 ft/s (0.9 m/s), Maximum 10.0 ft/s (3.0 m/s)\n\nAdditionally, for Incoloy 825 or Inconel 625 tubes, the maximum tube inlet velocity is 30 feet per second (9 meters per second)."
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What is the design pressure for cooling water?"
},
{
"role": "assistant",
"content": "13 barg."
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "How is the tube length selected for heat exchangers?"
},
{
"role": "assistant",
"content": "1. 6.1m 2. For straight tubes, standard tube lengths of 2440, 3050, 3660, 4880, 6100 and 7315 mm shall be used. For U-tubes, the maximum tube length shall be 7315 mm. The ratio of tube length to tube bundle outer diameter for removable bundles should not exceed 12 : 1. During the design stage the ease of handling of the tube bundle and exchanger shall be ensured. Tube lengths exceeding 7315 mm shall be subject to the approval of the Principal. The tube length for vertical thermosyphon reboilers shall not exceed 6100 mm."
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "1. fouling resistance for water 2. fouling factor for water"
},
{
"role": "assistant",
"content": "0.00035 m²-°C/W"
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What are the selection criteria for U-tube bundle heat exchangers?"
},
{
"role": "assistant",
"content": "1. U-tubes shall not be used if the fouling resistance exceeds 0.00052 m².K/W. 2. Tube-side fouling can be removed by chemical cleaning."
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What are the selection criteria for Fixed tubesheet heat exchangers?"
},
{
"role": "assistant",
"content": "Stresses caused by differential expansion between the tubes and the shell shall not exceed the design stress limits. A floating-head type or U-tube type heat exchanger should be selected if flexibility is required to avoid overstressing. The use of a flexible shell element is allowed only if required by specific process requirements and shall be agreed by the Principal. - Shell side fluid is non-fouling, or shell side fouling can be removed by chemical cleaning. Start-up, turn down and other operating scenarios shall be considered. Winter conditions, steaming out conditions, etc. shall be considered. Inspection requirements shall be considered"
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What are the conditions for using longitudinal baffles in heat exchangers?"
},
{
"role": "assistant",
"content": "the longitudinal baffle is welded to the shell (maximum allowable shell side pressure drop to be less than 0.7 bar)"
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What standards should shell-and-tube heat exchangers comply with?"
},
{
"role": "assistant",
"content": "Exchangers shall comply with TEMA Class R, API 660/ISO 16812, and the ASME Boiler and Pressure Vessel Code, Section VIII Division 1, and shall be suitable for ASME Code stamping when required."
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What cathodic protection measures should be used when the fluid is corrosive?"
},
{
"role": "assistant",
"content": "The requirements for the cathodic protection of heat exchangers using sacrificial anodes, impressed current systems or internal coatings are given in PTS 30.10.73.10. "
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "How can harmful oxide films on copper-nickel alloy tubes be detected?"
},
{
"role": "assistant",
"content": "In addition to the requirements of the standards for copper nickel tubes, an electrochemical test has to be specified to ensure that harmful oxide films which can form during fabrication are completely removed. These oxide films will cause severe pitting as they are more noble than the bare tube material. The electrochemical test procedure and requirements are given in (Appendix 2)."
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What should the tube-side velocity be for air-cooled heat exchangers?"
},
{
"role": "assistant",
"content": "The minimum flow velocity should be 1.0 m/s."
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What should the air design temperature be when designing air-cooled heat exchangers?"
},
{
"role": "assistant",
"content": "Under non-critical process conditions, the air design temperature shall be the higher of the following: - the highest air temperature which is exceeded for 400 hours per year; - 4 °C lower than the highest air temperature which is exceeded for 40 hours per year."
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What is the maximum allowable velocity in water service containing solids?"
},
{
"role": "assistant",
"content": "When the water carries solids, the maximum velocity shall be reduced by 20%."
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What is the fouling resistance for waxy crude in a distillation unit?"
},
{
"role": "assistant",
"content": "The fouling resistance for waxy crude is 0.57 x 10^-3 m²K/W."
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What is the pressure drop multiplier to consider when designing heat exchangers?"
},
{
"role": "assistant",
"content": "For fouling resistance between 0.00009 and 0.00033 m²K/W, the multiplier should be 1.1. For fouling resistance between 0.00034 and 0.00085 m²K/W, the multiplier should be 1.2. For fouling resistance between 0.00086 m²K/W and higher, the multiplier should be 1.5."
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What is the minimum tube diameter required for AIR COOLED EXCHANGERS?"
},
{
"role": "assistant",
"content": "The minimum tube diameter for air-cooled exchangers should be 1 inch (25 mm) outer diameter (OD) according to the provided specifications."
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What is the minimum wall thickness for steel tubes of AIR COOLED EXCHANGERS?"
},
{
"role": "assistant",
"content": "The minimum wall thickness for 1 inch (25 mm) to 1½ inches (38 mm) OD carbon steel or ferritic low alloy steel tubes is 0.109 inch (2.77 mm)."
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What is the maximum allowable design temperature for aluminum fins?"
},
{
"role": "assistant",
"content": "(1) The maximum allowable design temperature for aluminum fins wrapped under tension and mechanically embedded in grooves shall be 750°F (400°C). (2) The maximum allowable design temperature for inner tubes mechanically bonded to aluminum outer tubes from which fins have been formed by extrusion shall be 550°F (290°C). (3) The maximum allowable design temperature for aluminum footed fins wrapped under tension shall be 270°F (130°C). (4) The maximum allowable design temperature for knurled aluminum fins wrapped under tension shall be 350°F (180°C)."
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What losses should be included in the pressure drop on the shell side?"
},
{
"role": "assistant",
"content": "Pressure drops shall include entrance and exit losses. "
}
] |
[
{
"role": "system",
"content": "您是工程領域專家"
},
{
"role": "user",
"content": "What should be the minimum mean radius for U-bends in heat exchanger tubes?"
},
{
"role": "assistant",
"content": "The minimum mean radius should be 1.5 times the tube's outer diameter."
}
] |
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