Electric Heater Cavity Design for Hydrocarbon Stream Heating

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Solution Overview

Problem

Existing electric heaters for hydrocarbon process streams face inefficiencies due to non-uniform heat transfer, high thermal resistances, and the generation of carbon dioxide from combustion, which can lead to hot spots and metal-catalyzed coking.

Innovation Solution

The development of new electric heater designs featuring a body with a cavity and a plurality of electrical heating elements arranged along the flow direction, with adjustable heat flux and thermal conductivity zones to optimize heat transfer and reduce coking risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If fired heating is used to heat hydrocarbon process streams, then heating capability is provided, but thermal efficiency is low (only 60% of thermal energy is transferred) and carbon dioxide emissions are generated

Engineering Contradiction:

Improvethermal efficiencyVSAvoidcarbon dioxide emissions

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the fired heating system (combustion-based thermal system) with an electric heating system. The electric heater uses electrical energy to generate heat through resistive heating elements, eliminating the combustion process that produces CO2 emissions. This substitution transitions from a chemical/thermal system to an electrical system, achieving both improved thermal efficiency (electric heaters can transfer nearly 100% of generated heat to the process stream) and elimination of carbon dioxide emissions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If high heat flux is applied in fired heating, then heating efficiency improves, but hot spots are created in metallic conduit leading to metal catalyzed coking

Engineering Contradiction:

Improveheating efficiencyVSAvoidhot spots and coking

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies different heat flux levels to different zones within the heater cavity. The heating elements are arranged and controlled to provide higher heat flux in the central region and lower heat flux near the metallic walls. This non-uniform heat distribution prevents localized overheating (hot spots) at the walls that would cause metal catalyzed coking, while maintaining high overall heating efficiency through optimized heat flux in the bulk fluid region.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the heat flux parameter spatially within the heater by using multiple heating elements with different power levels or by positioning elements at different distances from the process stream. This parameter variation allows the system to maintain high heating efficiency in the bulk fluid while reducing heat flux near metallic surfaces to prevent coking, thus resolving the contradiction between heating efficiency and hot spot formation.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If electric heating elements are arranged to provide high heat flux for efficient heating, then heating efficiency improves, but non-uniform heat transfer occurs creating hot spots

Engineering Contradiction:

Improveheating efficiencyVSAvoidheat distribution uniformity

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent implements spatially varying heat flux distribution by arranging heating elements to provide different heat flux levels in different zones. The central heating elements operate at higher power to efficiently heat the bulk process stream, while heating elements near the walls operate at lower power or are thermally isolated from the metallic walls. This local quality variation achieves both high overall heating efficiency and uniform heat distribution, preventing hot spots.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

These designs enhance heat transfer efficiency, reduce the risk of hot spots and coking, and minimize carbon dioxide emissions by optimizing the arrangement and thermal properties of the electrical heating elements.

Implementation Method 1

a plurality of electrical heating elements extending into the cavity, the electrical heating elements arranged along a direction of flow from the inlet to the outlet

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS20250142677A1Electric heater for heating a hydrocarbon process stream

Publication Date: 2025.05.01 UOP LLC

AI summary

Electric heaters for heating a hydrocarbon process stream. The electric heater has a cavity with parallel walls which may provide a rectangular cross section to the cavity. The parallel side walls may be parallel to a longitudinal axis of the electrical heating elements which extend into the cavity to transfer heat to fluid passing there through. Various configurations and orientations of the electrical heating elements are provided.