Hydrogen Production from Aqueous Effluents via Nanofiltration and Electrolysis
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Solution Overview
Problem
Current methods for producing hydrogen from agricultural effluents, such as pig slurry and sewage plant sludge, are energy-intensive, environmentally unfriendly due to high CO2 emissions, and face challenges with chloride ions in seawater, while existing recovery techniques for slurry result in nitrogen pollution and ammonia emissions.
Innovation Solution
A process involving nanofiltration, ammonia stripping, reverse osmosis, and electrolysis of aqueous liquid effluents to produce hydrogen gas and ammonium sulphate, utilizing heat from electrolysis to enhance ammonia volatility and employing renewable energy sources like photovoltaic collection and wind turbines, with ceramic nanofiltration membranes and controlled pressure differentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If steam reforming of biogas is used to produce hydrogen, then hydrogen production is achieved, but 9 kg of CO2 are released into the atmosphere for every 1 kg of hydrogen produced
Solution Approach 1:
The invention extracts and removes CO2 from the biogas stream before the reforming process through acidification and decarbonation steps. CO2 is separated from the biogas and replaced with water vapor, so that the reforming reaction produces hydrogen without the harmful CO2 emissions that would normally result
Solution Approach 2:
The invention converts the harmful CO2 component of biogas into a useful product. By acidifying the biogas and reacting with calcium oxide, CO2 is captured and converted into calcium carbonate, which can be used as a fertilizer or soil amendment, thus transforming a harmful emission into a beneficial product
2Quantity of substance
If stripping methods are used to extract ammoniacal nitrogen from liquid fraction, then ammonium sulphate fertiliser is produced, but a lot of energy is consumed
Solution Approach 1:
The invention changes the pH parameter of the liquid fraction through acidification (adding sulfuric acid), which transforms ammoniacal nitrogen into ammonium ions. This parameter change enables ammonia stripping to occur at lower temperatures and with lower energy consumption compared to conventional thermal stripping methods
3Quantity of substance
If seawater is used for electrolysis to produce hydrogen, then fresh water consumption is reduced, but chloride ions corrode the anode and prevent or limit oxidation-reduction reactions
Solution Approach 1:
The invention extracts and removes chloride ions from the seawater through ion exchange resins before the water undergoes electrolysis. This extraction eliminates the corrosive effect of chloride ions on the electrolyser anode while still allowing the use of seawater as the source, thus resolving the contradiction between reducing fresh water consumption and maintaining electrolyser reliability
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 process reduces energy consumption, minimizes environmental impact by lowering CO2 emissions, and effectively recovers ammonia as ammonium sulphate from diverse effluents, including urine, with significant reductions in nutrient content and energy usage.
Implementation Method 1
nanofiltration of said aqueous liquid effluent or said mixture of aqueous liquid effluents so as to obtain a permeate
Implementation Method 2
treatment by reverse osmosis of at least part of the permeate extracted from the ammonia stripping unit after said ammonia stripping step
Implementation Method 3
electrolysis of at least part of said osmosis aqueous solution so as to decompose said part of said osmosis aqueous solution into at least gaseous dihydrogen
Implementation Method 4
ammonia stripping of the permeate from said nanofiltration step in an ammonia stripping unit so as to obtain ammonium sulphate
Data Source
AI summary
The invention concerns a process for producing gaseous dihydrogen and ammonium sulphate from an aqueous liquid effluent containing organic and inorganic materials or a mixture of aqueous liquid effluents,said process comprising the following steps:nanofiltration of said aqueous liquid effluent or said mixture of aqueous liquid effluents so as to obtain a permeate;ammonia stripping of the permeate from said nanofiltration step in an ammonia stripping unit so as to obtain an ammonium sulphate;treatment by reverse osmosis of at least part of the permeate extracted from the ammonia stripping unit after said ammonia stripping step, so as to obtain an osmosed aqueous solution;electrolysis of at least part of said osmosis aqueous solution so as to decompose said part of said osmosis aqueous solution into at least gaseous dihydrogen.