Refinery furnace selection: which heater type is most commonly used to raise crude oil temperature before it enters the atmospheric fractionation tower?

Introduction:
Before crude oil enters the atmospheric distillation column, it must be heated to near its flash zone temperature to vaporize distillable fractions. The equipment choice impacts fuel efficiency, coking tendency, and run length. This question focuses on the standard refinery practice for front-end heating of crude feeds.

Given Data / Assumptions:

• Service: preheating crude oil to 320–380°C (typical range) before fractionation.
• Large throughputs and continuous operation.
• Fuel firing with heat recovery via preheat trains is common.

Concept / Approach:
The industry-standard unit is a pipestill fired heater (often called the crude furnace). Crude flows through tubes in radiant and convection sections, picking up heat from combustion gases. Electric immersion heaters are unsuitable for such high flow and temperature duties at scale; steam coil heaters cannot achieve the required final temperature economically for large crude rates.

Step-by-Step Solution:
Identify duty: bring crude to flash-zone approach temperature.Select heater capable of high, controllable outlet temperatures with good film coefficients: pipestill fired heater.Confirm practicality: widely used, compatible with heat-integration trains.

Verification / Alternative check:
Typical PFDs show crude preheat by heat exchangers (against product side-draws) followed by a pipestill furnace to reach the final target temperature before the atmospheric column.

Why Other Options Are Wrong:

• Electric immersion: impractical at refinery crude rates and temperatures.
• Steam coils: limited approach temperature and high steam consumption.
• None of these: contradicts common practice.

Common Pitfalls:
Ignoring tube metal temperature limits and coking risk; these are handled by proper firing, residence time control, and decoking schedules in pipestill heaters.

Final Answer:
Pipestill fired heater (crude furnace)