30. Engineering Design Guidelines For Furnaces - KLM Technology ...

KLM TechnologyGroupPractical EngineeringGuidelines for Processing PlantSolutionsFURNACE(ENGINEERING DESIGN GUIDELINES)Page 20 of 80Rev: 02May 2012Heat Density - The rate of heat transfer per unit area to a tube, usually based on totaloutside surface area.Heat Duty - The total heat absorbed by the process fluid, usually expressed in MBtu/hrInduced Draft - Use of a fan to provide the additional draft required over that supplied bythe stack, to draw the flue gas through the convection section, and any downstream heatrecovery equipment.Lower Heating Value (LHV) - The theoretical heat of combustion of a fuel, when nocredit is taken for the heat of condensation of water in the flue gas.Mass Velocity - The mass flow rate per unit of flow area through the coil. Typical unitsare lb/s-sq. ft.Natural Draft - System in which the draft required to move combustion air into the heaterand flue gas through the heater and out the stack is provided by stack effect alone.Net Fuel - The fuel that would be required in the heater if there were no radiation losses.One-Side Fired Tubes - Radiant section tubes located adjacent to a heater wall haveonly one side directly exposed to a burner flame. Radiation to the back side of the tubesis by reflection/ re-radiation from the refractory wall.Pass - A coil that transports the process fluid from fired heater inlet to outlet.Radiant Section - The section of the fired heater in which heat is transferred to theheater tubes primarily by radiation from high-temperature flue gas.Service Factor – A measure of the continuity of operation, generally expressed as theratio of total running days for a given time period to the total calendar days in the period.Shield Section - The first two tube rows of the convection section.Sootblower - A steam lance (usually movable) in the convection section for blowing sootand ash from the tubes using high-pressure steam.These design guideline are believed to be as accurate as possible, but are very general and not for specific designcases. They were designed for engineers to do preliminary designs and process specification sheets. The finaldesign must always be guaranteed for the service selected by the manufacturing vendor, but these guidelines willgreatly reduce the amount of up front engineering hours that are required to develop the final design. The guidelinesare a training tool for young engineers or a resource for engineers with experience.This document is entrusted to the recipient personally, but the copyright remains with us. It must not be copied,reproduced or in any way communicated or made accessible to third parties without our written consent.