Cracking Furnace Indirect Heating for Tar Purification
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Solution Overview
Problem
Current methods for purifying gas from thermal treatment of biomass and waste, such as pyrolysis or gasification, are inadequate in removing tars and oily phases, leading to gas engines being unable to use the recovered gas safely due to residual impurities.
Innovation Solution
A cracking furnace with a vertical tubular enclosure and a coaxially arranged heating tube, where the gas is heated indirectly by a burner, creating a confined treatment zone for efficient heat exchange and rapid cracking of tars and oil phases, resulting in a gas suitable for use in gas engines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plasma torch is used for cracking, then tars and oily phases are cracked effectively, but the cost becomes relatively expensive
Solution Approach 1:
The patent replaces expensive plasma torches with a more economical indirect heating system using a fire tube and combustion chamber. This substitution uses conventional combustion technology rather than expensive plasma generation equipment, achieving similar cracking effectiveness at lower cost.
Solution Approach 2:
The patent replaces the plasma torch system with an indirect thermal cracking system using a fire tube heated by combustion. This substitutes a complex plasma generation system with a simpler thermal conduction-based system, reducing equipment cost while maintaining purification effectiveness.
2Ease of manufacture
If indirect heating of the pipe by heating gas is used, then cost is reduced, but purification of tars and oily phases is not thorough
Solution Approach 1:
The patent introduces a fire tube as an intermediary heat transfer medium. The fire tube is directly heated by combustion in the combustion chamber and then transfers this heat indirectly to the process pipe containing the gas to be cracked. This intermediary system enables thorough purification while maintaining the cost benefits of indirect heating.
Solution Approach 2:
The heating system is segmented into two distinct zones: a combustion chamber for generating heat and a fire tube for heat transfer. This segmentation allows the combustion process to occur separately from the cracking process, enabling more effective heat transfer to the process pipe and improving purification effectiveness while maintaining cost efficiency.
3Productivity
If the heating tube extends inside the chamber coaxially with the chamber, then heat exchange efficiency is improved and cracking is rapid, but device complexity increases
Solution Approach 1:
The fire tube serves multiple functions: it acts as a combustion chamber for generating heat, a heat transfer medium for heating the process pipe, and a structural support element. This multi-functionality achieves rapid cracking through efficient heat exchange while avoiding the need for separate heating devices, thereby limiting the increase in device complexity.
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 described configuration ensures thorough purification of tars and oily phases, producing a gas of sufficient purity for use in gas engines, with the furnace being relatively autonomous and cost-effective.
Implementation Method 1
the specific arrangement of the chamber and the heating tube creates a treatment zone in which the gas is well confined. This promotes heat exchange within the chamber between the gas being treated and the heating tube
Implementation Method 2
the indirect heating of the pipe by the heating gas then triggers a cracking reaction of the tars and oily phases contained in the gas
Implementation Method 3
the indirect heating of the pipe by the heating gas then triggers a cracking reaction of the tars and oily phases contained in the gas
Data Source
Figure 1~2
AI summary
The invention relates to a cracking furnace (1) containing a tubular vertical chamber (2) which comprises an inlet (4) for introducing a gas to be treated and an outlet (5) for removing said gas from the chamber, means for heating said gas which comprise a heating tube (9) extending vertically inside the chamber and coaxial with the chamber, the heating tube being shaped in such a way as to have a closed lower end and being arranged in such a way that the lower end thereof is arranged in the chamber and such that the upper end thereof is connected to a burner (13) of the heating means arranged outside the chamber. The invention also relates to an assembly comprising such a cracking furnace and a device for thermal treatment of biomass and/or waste, an outlet of which is connected to the inlet of said cracking furnace.