Fast Pyrolysis Heat Exchanger with Indirect Heat Carrier

Solution Overview

Problem

Existing fast pyrolysis systems face challenges in efficiently transferring heat to biomass in an oxygen-free environment, leading to compromised oxygen integrity, difficulty in harvesting bio-char, and imprecise temperature control.

Innovation Solution

A closed loop multi-tube heat exchanger system with a vacuum-activated hot gas blow back filter, which uses a heat carrier to transfer heat indirectly to biomass, maintaining an oxygen-free environment and allowing for precise temperature control and char harvesting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If direct surface contact heat transfer is used, then heat transfer efficiency is improved, but the required surface area becomes very large requiring a larger reactor

Engineering Contradiction:

Core Design Contradiction:

PowerVSVolume of moving object

Solution Approach 1:

The patent introduces a heat carrier (sand, steel shot, or ceramic shot) as an intermediary substance to transfer heat from the furnace to the biomass. This heat carrier circulates between the furnace and reactor, enabling efficient heat transfer without requiring direct surface contact between the heating elements and biomass, thus reducing the required reactor surface area and volume.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by stationary object

If an open loop furnace is used to move heat carrier and char mixture, then heat carrier can be re-heated, but the oxygen free integrity is compromised and char cannot be harvested

Engineering Contradiction:

Core Design Contradiction:

Use of energy by stationary objectVSReliability

Solution Approach 1:

The system is divided into separate functional zones: an oxygen-free reactor where pyrolysis occurs and char is produced, and a separate furnace where the heat carrier is re-heated. The heat carrier is circulated between these zones, allowing the reactor to maintain oxygen-free integrity while the furnace provides necessary heating without compromising the oxygen-free environment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The heat carrier serves as an intermediary that transfers thermal energy from the furnace to the biomass in the reactor without direct contact between the biomass and the furnace environment. This allows the heat carrier to be heated in the furnace and then transferred to the oxygen-free reactor, maintaining oxygen-free integrity while enabling heat carrier re-heating.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If mechanical separation systems like cyclones are used, then larger particles can be removed, but fine char particles remain in the vapor

Engineering Contradiction:

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent employs a ceramic baghouse filter with porous structure to separate char particles from the vapor stream. The porous ceramic material allows vapor to pass through while trapping both large and fine char particles, achieving high removal efficiency and precise separation that mechanical cyclones cannot accomplish alone.

Inventive Principle:

Principle #31Porous materials

4Productivity

If ceramic baghouse is used to filter vapor, then char particles can be removed, but vapor condenses on the bags forming a hard crust

Engineering Contradiction:

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The system maintains the ceramic baghouse filter at elevated temperatures to prevent vapor condensation. By controlling the temperature parameter of the filter, the system keeps the vapor in a gaseous state as it passes through the porous ceramic bags, allowing char particle removal without forming a hard crust that would block the pores and stop operation.

Inventive Principle:

Principle #35Parameter changes

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

The system achieves efficient and economical heat transfer to biomass, maintains oxygen-free integrity, allows for precise temperature control, and enables the harvesting of bio-char, thereby improving the overall efficiency and viability of fast pyrolysis processes.

Implementation Method 1

A closed loop multi-tube heat exchanger system with a vacuum-activated hot gas blow back filter, which uses a heat carrier to transfer heat indirectly to biomass

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

vacuum-activated hot gas blow back filter

Methodology Applied

Scientific EffectFiltration: Filter (physical)

Implementation Method 3

vacuum-activated hot gas blow back filter

Methodology Applied

Scientific EffectVacuum: Vacuum

Data Source

PatentUS12331249B2Fast pyrolysis heat exchanger system and method

Publication Date: 2025.06.17

AI summary

A fast pyrolysis heat exchanger system for economically and efficiently converting biomass and other combustible materials into bio-oil. The system employs multiple closed loop tubes situated inside the heat exchanger. As a granular solid heat carrier is deposited at the top of the heat exchanger and caused to move downwardly therethrough, heat is transferred from the tubes to the heat carrier which is then transferred to a reactor where it is placed in contact with the combustible materials.