SOFC Anode Off-Gas Reflux for Bioethanol Distillation Energy Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current combined systems of bioethanol producing devices and solid oxide fuel cells (SOFCs) do not adequately enhance electric power generation efficiency and reduce energy consumption for distillation of fermented liquids.
Innovation Solution
The method involves refluxing a part of the anode off-gas from the SOFC back to the mash column to control the ethanol concentration of the water-containing ethanol vapor supplied to the reforming device within a range of 25 to 35% by weight, and utilizing catalytic combustors to combust anode and cathode off-gases for heat generation, which is used to heat the reforming device and mash column.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ethanol concentration is increased to 99.5% by weight for automobile fuel, then fuel quality is improved, but energy consumption for distillation-purification increases significantly
Solution Approach 1:
The invention changes the operating parameters of the SOFC (temperature, pressure, fuel composition) to enable direct use of low-concentration ethanol (25-35% by weight) without requiring high-concentration purification. The reforming device operates at temperatures that facilitate in-situ reforming of ethanol to hydrogen, eliminating the need for energy-intensive distillation to achieve 99.5% ethanol concentration.
Solution Approach 2:
The invention extracts and utilizes the chemical energy directly from the ethanol fermentation broth (25-35% concentration) through the reforming device and SOFC system, bypassing the traditional distillation step. The reforming device extracts hydrogen from ethanol in-situ, and the SOFC converts this hydrogen to electricity, removing the need for energy-consuming high-concentration purification.
2Manufacturing precision
If a distillation column is used to enrich ethanol to high concentration, then fuel quality is improved, but equipment cost and energy consumption increase
Solution Approach 1:
The invention removes the distillation column from the system by extracting and utilizing low-concentration ethanol (25-35%) directly through the reforming device. The reforming device performs in-situ conversion of ethanol to hydrogen, eliminating the need for complex distillation equipment while maintaining system effectiveness.
Solution Approach 2:
The SOFC system performs self-service by directly utilizing the ethanol fermentation broth (25-35% concentration) as fuel without requiring external purification equipment. The reforming device and SOFC work together to convert the low-concentration ethanol directly into electrical energy, making the system self-sufficient and eliminating complex distillation equipment.
3Ease of operation
If anode off-gas is discharged without utilization, then system operation is simplified, but energy waste increases
Solution Approach 1:
The invention recovers the energy contained in the anode off-gas by introducing it back into the reforming device. The off-gas, which contains unreacted hydrogen and other combustible components, is reused as fuel in the reforming process, thereby recovering energy that would otherwise be wasted and improving overall system efficiency.
Solution Approach 2:
The invention merges the anode off-gas stream with the fuel feed to the reforming device, combining waste gas with fresh fuel sources. This integration allows the off-gas to be reused productively in the reforming process, eliminating energy waste while maintaining system operational simplicity.
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
This approach enhances the electric power generation efficiency of the SOFC, increases the utilization rate of combustible components, and minimizes the energy consumption for distillation by optimizing ethanol concentration and heat utilization.
Implementation Method 1
a mash column that distills a fermented liquid formed in a fermenting vessel of a bioethanol producing device to distill off a water-containing ethanol vapor from an overhead thereof
Implementation Method 2
distill off a water-containing ethanol vapor from an overhead thereof
Implementation Method 3
a reforming device that forms a reformed gas from the water-containing ethanol vapor
Implementation Method 4
a solid oxide fuel cell that is operated with the reformed gas as a fuel
Implementation Method 5
utilizing catalytic combustors to combust anode and cathode off-gases for heat generation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention is to provide, in a combined system of a bioethanol producing device and an SOFC, a method that is capable of further enhancing the electric power generation efficiency of the SOFC, and is also capable of achieving further reduction of the energy required for distillation of the fermented liquid. A part of an anode off-gas is refluxed to the water-containing ethanol vapor line from the mash column to the reforming device at a reflux ratio ((flow rate of reflux gas) / (flow rate of (anode off-gas) - (reflux gas))) of from 1 to 2. The ethanol concentration of the water-containing ethanol vapor is controlled by refluxing, to a range of from 25 to 35% by weight with water contained in the anode off-gas of the solid oxide fuel cell.