Formic Acid Production via Bipolar Membrane Electrodialysis
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Solution Overview
Problem
Current methods for producing formic acid from carbon dioxide are inefficient, often requiring pure carbon dioxide, high energy input, and result in formate contamination, while lacking a durable and cost-effective process that can utilize sustainable electrical energy and handle dilute carbon dioxide sources like air or flue gases.
Innovation Solution
A process combining carbon capture with hydrogenation and bipolar membrane electrodialysis, where carbon dioxide is contacted with an alkaline solution, converted to formate, and then processed through bipolar membrane electrodialysis to produce a concentrated formic acid solution, recycling the alkaline solution, which can further convert formic acid to formaldehyde using renewable hydrogen sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If carbon dioxide is captured using conventional ammonia capture solvent and hydrogenated, then formate salt is produced, but the conversion rate to formic acid is low and formate contamination remains high
Solution Approach 1:
The patent replaces conventional thermal distillation with bipolar membrane electrodialysis (BMED) to separate formic acid from formate salts. BMED uses electrochemical principles with bipolar membranes that generate H+ and OH- ions at interfaces, enabling formic acid concentration in the acid compartment while regenerating alkaline solution in the base compartment, achieving both high purity and high conversion rate simultaneously
Solution Approach 2:
The patent changes the separation mechanism from thermal-based distillation to electrochemical-based electrodialysis. By applying electrical potential across bipolar membranes, the system achieves selective ion transport that concentrates formic acid while regenerating alkaline capture solution, overcoming the limitations of thermal methods
2Productivity
If pure carbon dioxide is used as feedstock, then formic acid production efficiency improves, but the requirement for pure CO2 increases process complexity and cost
Solution Approach 1:
The alkaline solution serves multiple functions: (1) captures CO2 from dilute sources like air or flue gas, (2) provides the alkaline environment for hydrogenation to formate, and (3) is regenerated by BMED for reuse. This multi-functionality eliminates the need for pure CO2 concentration steps and simplifies the overall process
Solution Approach 2:
The BMED system self-regenerates the alkaline capture solution from the formate-containing alkaline stream. The bipolar membranes automatically generate OH- ions in the base compartment, restoring the alkaline solution's CO2 capture capacity without requiring external chemicals or energy-intensive thermal processing
3Manufacturing precision
If conventional distillation is used to concentrate formic acid, then pure formic acid can be obtained, but energy consumption increases significantly
Solution Approach 1:
The patent replaces thermal distillation with electrochemical electrodialysis. BMED uses electrical energy to drive ion migration across selective membranes, concentrating formic acid in the acid compartment while simultaneously regenerating alkaline solution, achieving energy efficiency superior to thermal methods
Solution Approach 2:
The patent changes from thermal energy input to electrical energy input for concentration. By applying controlled electrical potential across the electrodialysis stack, the system achieves formic acid concentration without the high temperatures required for distillation, reducing overall energy consumption
4Adaptability or versatility
If dilute carbon dioxide sources like air or flue gas are used, then sustainability improves, but the capture efficiency decreases
Solution Approach 1:
The alkaline solution is designed to universally capture CO2 from various dilute sources including air (Direct Air Capture) and flue gases. The high alkalinity and continuous regeneration capability enable efficient CO2 uptake from low-concentration streams, making the process adaptable to diverse sustainable feedstocks
Solution Approach 2:
The BMED system continuously regenerates the alkaline capture solution, maintaining its CO2 capture capacity throughout operation. This continuous regeneration enables sustained high-efficiency capture from dilute sources without interruption or loss of capture performance over time
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 integrated process efficiently produces concentrated formic acid with minimal formate contamination, utilizing dilute carbon dioxide sources and sustainable energy, reducing energy consumption and operational costs, and enabling the production of formaldehyde from carbon dioxide.
Implementation Method 1
a carbon capture step wherein a source of carbon dioxide is contacted with an alkaline solution to obtain a solution comprising carbonate and/or bicarbonate
Implementation Method 2
subjecting the solution comprising carbonate and/or bicarbonate to a hydrogenation step in the presence of a catalyst to obtain a solution comprising formate
Implementation Method 3
subjecting the solution comprising formate obtained in step (c) to bipolar membrane electrodialysis to obtain a concentrated formic acid solution and a recovered alkaline solution
Data Source
AI summary
The invention concerns a process and modular system for producing formic acid from a source of carbon dioxide. The process according to the invention comprises (a) a carbon capture step wherein a source of carbon dioxide is contacted with an alkaline solution to obtain a solution comprising carbonate and/or bicarbonate; optionally (b) subjecting the solution comprising carbonate and/or bicarbonate to alkaline water electrolysis, wherein carbonate present in the solution comprising carbonate and/or bicarbonate is converted to bicarbonate and H2O is converted into H2 and O2; (c) subjecting the solution comprising carbonate and/or bicarbonate to a hydrogenation step in the presence of a catalyst to obtain a solution comprising formate; and (d) subjecting the solution comprising formate obtained in step (c) to bipolar membrane electrodialysis to obtain a concentrated formic acid solution and a recovered alkaline solution, wherein the recovered alkaline solution obtained in step (d) is recycled back to step (a). The concentrated formic acid solution obtained from step (d) may be subjected to a hydrogenation step in the presence of a hydrogenation catalyst to obtain a concentrated formaldehyde solution.