Horizontal Reactor for Char Surface Area and Syngas Yield
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Solution Overview
Problem
Existing processes for producing a char product with high BET surface area and improving the yield of gaseous fraction in tubular reactors are limited in achieving optimal results, particularly in terms of BET surface area and syngas yield.
Innovation Solution
A process involving torrefied biomass particles with 60-80 wt% volatile content, where the particles are fed to a horizontally positioned reactor furnace and contacted with a reactive gaseous mixture of steam and oxygen, with a specific oxygen-to-steam ratio and temperature control to enhance BET surface area and gaseous fraction yield, including carbon monoxide, hydrogen, and hydrocarbons, by optimizing the distribution of oxygen and steam along the reactor length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If more oxygen and steam is supplied to the downstream end part of the reactor, then the BET surface area of the char product is increased, but the temperature of the gaseous fraction becomes lower which may affect syngas quality
Solution Approach 1:
The patent applies local quality by differentiating the oxygen and steam supply along the reactor length. More oxygen and steam are supplied to the downstream end part compared to the upstream end part. This creates different reaction conditions in different zones: the downstream zone produces char with higher BET surface area through enhanced oxidation, while the upstream zone maintains higher temperatures for syngas production. The non-uniform distribution resolves the contradiction by allowing each zone to optimize for its specific function.
2Area of stationary object
If the total amount of oxygen supplied to the reactor furnace is increased, then the BET surface area of the char product is improved, but the yield of the gaseous fraction decreases
Solution Approach 1:
The patent resolves this contradiction through local quality by spatially distributing oxygen supply. While the total oxygen amount is optimized for char production, the distribution is non-uniform: downstream end part receives more oxygen to maximize char surface area, while upstream end part receives less oxygen to preserve gaseous fraction yield. This spatial differentiation allows simultaneous optimization of both competing objectives.
Solution Approach 2:
The reactor is segmented into upstream and downstream end parts with different oxygen supply rates. This segmentation allows independent optimization of reaction conditions in each zone: the downstream zone is optimized for char surface area through higher oxygen concentration, while the upstream zone is optimized for gaseous fraction production through lower oxygen concentration. The segmentation principle enables the system to achieve both high BET surface area and high gaseous fraction yield.
3Speed
If the temperature in the reactor furnace is increased, then the reaction rate is improved, but the ash compounds may melt and form slag
Solution Approach 1:
The patent applies local quality by creating different temperature zones through non-uniform oxygen and steam distribution. The downstream end part, receiving more oxygen and steam, operates at lower temperatures that prevent ash melting and slag formation, while the upstream end part maintains higher temperatures for enhanced reaction rate. This spatial temperature differentiation resolves the contradiction between reaction rate and slag prevention.
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 process achieves a higher BET surface area for the char product and increases the yield of the gaseous fraction, resulting in improved syngas production, while maintaining ash compounds in a usable form for recycling and ensuring no slag formation.
Implementation Method 1
the particles of the torrefied biomass are contacted in the solids pathway zone with a reactive gaseous mixture comprising of steam and oxygen
Implementation Method 2
a char product having a high BET surface area and gaseous fraction comprising of carbon monoxide, hydrogen and hydrocarbons starting from particles of a torrefied biomass
Implementation Method 3
the temperature in the reactor furnace is between 400 and 800° C. and the solid residence time in the solids pathway zone is between 10 and 80 minutes
Data Source
AI summary
The invention is directed to a process to continuously prepare a char product having a high BET surface area of above 400 m2/g and gaseous fraction comprising of carbon monoxide, hydrogen and hydrocarbons starting from particles of a torrefied biomass in an elongated and substantially horizontally positioned reactor furnace. A reactive gaseous mixture of steam and oxygen is supplied to the solids in the reactor and more oxygen and steam is supplied to the downstream end part of the reactor as compared to the amount of oxygen supplied to the upstream end part.