Preparation of Fired Heater Specs

1. Purpose

This procedure outlines heater project specifications preparation.

2. Preparation of Information

The Process Engineer submits fired heater design basis information to the Heater Group approximately 2 weeks prior to the P&ID drafting consultation.

2.1 Process Specification Heater Summary Sheet, English and Metric

The Process Engineer reviews the process specifications heater summary sheet. If the heater outlet pressure on the summary sheet and in the process datafile is equal or close (±5 percent) to the heater outlet pressure determined in the hydraulics, no changes are required. If the two pressures are substantially different, the Heater Specialist will consult the Process and Project Engineers prior to modifying the data. When changing the heater outlet pressure on the heater summary sheet, the Process Engineer shall also update the process datafile for the new conditions. If the heater outlet conditions and/or column conditions are changed, create a new Heater Summary Sheet with the correct process datafile and resend it to the Heater Specialist.

If the heater outlet is all liquid (0% vaporization), the agreement in heater outlet pressure between the hydraulics and the process datafile is less important and the process datafile does not require adjustment.

2.2 Heater Design Contingency

If a special contingency is added to the heater design above the normal process design case, the Process Engineer shall indicate the basis for the contingency (e.g., start-up, fouled upstream exchanger, customer request). Indicate whether or not to consider the contingency case at the same percent vaporization, increasing flow rate to heater; at the same flow rate, increasing percent vaporization; or at a lower inlet temperature, keeping flow rate and percent vaporization the same as the normal case. If the inlet temperature is decreased, the Process Engineer creates a datafile with the appropriate heater inlet conditions.

2.3 Heater Design Pressure

If the Process Engineer submits the heater information to the Heater Specialist before the process hydraulics have been finalized, show the design pressure as estimated (est.). When final design pressures are available, transmit this information separately in writing to the Heater Specialist as a revision to the previously submitted information. Include estimated design pressures and coil pressure drops for steam coils (preheat, generation and superheat), if available. The Heater Specialist conducts the steam system design calculations for the steam system and auxiliaries. The Heater Specialist establishes the design pressures for the steam system and auxiliaries based upon the pressure drop determinations.

2.4 Equipment Name (Service) and Item Number

The equipment Name (Service) corresponds exactly with the Equipment List (Project Specification 112).

2.5 Basic Engineering Design Questionnaire (BEDQ)

The Project Manager confirms that the Heater Specialist has the latest version of the BEDQ. If the BEDQ has been revised, supply the Heater Specialist with updated fuels and heater sections.

2.6 Waste Gas/Liquid Streams

The Process Engineer shall provide information (flow, composition, temperature, pressure) on all waste gas streams burned in the heater(s). These waste streams may originate from other units in the complex. The Heater Specialist shall discuss with the Project Manager and other Process and Project Engineers exactly where and how to handle these streams. Provide similar information (mass flow, viscosity, gravity, temperature, etc.) for any waste liquid streams to be burned.

2.7 Project Manger Input

The Heater Specialist shall discuss anticipated heater design requirements with the Project Manager to determine if any decisions have been made based upon previous discussions with other Heater Specialists. The Project Manager shall supply specific design basis information for special heater requirements, such as common convection sections, steam generation, air preheat, and common or individual stacks. Any low or no flow requirements for steam superheaters and other coils shall also be identified.

2.8 Turndown Requirements

Provide information on any special turndown requirements below the standard 60 percent of normal, including process flow, duty, temperature, and pressure.

2.9 Fuel Gas Treatment

When there are multiple units with fired heaters within a complex, indicate under which project number the Project Specification 965 – Fuel Gas Preparation System will be issued. The Project Manager will determine whether multiple fuel gas preparation systems will be needed based on plot plan. The Project Engineer will complete the 965 Specification.

3. P&ID Considerations

Ask the Heater Specialist to review the heater design basis prior to the P&ID drafting consultation, especially if the heater is complicated or if a Project Specification 201 - Inflection Point Engineering Heaters is generated. The Heater Specialist provides input to or participates in the P&ID consultation to assure that the most appropriate P&ID modules are selected for drafting.

The Project Engineer ensures that the P&IDs accurately reflect the requirements of the Heater Project Specifications. If the heater project specifications are not complete before the end of the P&ID check, the Heater Specialist participates in the check to assure that the P&ID accurately reflects the pending heater design specification.

4. Specification Tool

The 201, 202 and 207 heater specifications will be prepared using Tool . This will be done by a Heater Specialist.