Citrus Peel Solubilization via Basic Treatment and Catalytic Oxidation
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Solution Overview
Problem
The disposal of citrus peels from the orange processing industry poses challenges due to their high volume, biodegradability, and the presence of essential oils, which inhibit anaerobic digestion processes, leading to increased disposal costs and regulatory compliance issues, with existing technologies like drying, enzymatic extraction, and biogas production being economically or practically ineffective.
Innovation Solution
A process involving a basic treatment of orange peels at 150-250°C to solubilize them, followed by catalytic oxidation using manganese and cerium-based catalysts at 150-240°C and 9-27 bar oxygen pressure, reducing the organic load and making the waste suitable for biological treatment or producing a stable biomass product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If drying of orange peels is performed to obtain cattle feed, then the product can be stored and transported, but the disposal costs increase due to high energy consumption
Solution Approach 1:
The patent uses steam explosion to rapidly heat and then rapidly cool the citrus peel, causing phase transitions in the water content and cellular structure. This thermal shock disrupts the cell walls and releases essential oils without requiring prolonged high-temperature drying, thus achieving stabilization with lower energy input compared to conventional drying methods
Solution Approach 2:
The patent replaces the mechanical drying system with a chemical-biological treatment system. By using steam explosion followed by controlled biodegradation in a bioreactor, the process achieves waste stabilization through biochemical pathways rather than thermal evaporation, significantly reducing energy consumption while maintaining product stability
2Quantity of substance
If enzymatic extraction or microwave treatment is performed to extract natural substances, then bioflavonoids and carotenoids can be obtained, but the treatment costs increase significantly
Solution Approach 1:
The patent changes the physical-chemical parameters of the citrus peel through steam explosion (temperature, pressure, time) to make the cell walls more permeable and the essential oils more accessible. This pre-treatment enhances the efficiency of subsequent biodegradation processes, allowing for effective substance extraction at lower costs compared to direct enzymatic or microwave treatment
Solution Approach 2:
The patent applies steam explosion as a preliminary treatment before any extraction or biodegradation process. This pre-treatment breaks down the rigid cell wall structure of the citrus peel, making the intracellular compounds (bioflavonoids, carotenoids, essential oils) more accessible to enzymes or other extraction methods, thereby reducing the intensity and cost of subsequent treatment steps
3Use of energy by moving object
If anaerobic digestion is performed for biogas production, then energy can be recovered, but the process is inhibited by essential oils in the peel
Solution Approach 1:
The patent applies steam explosion as a preliminary treatment to disrupt the cell walls and release essential oils from their protective compartments. By doing so before anaerobic digestion, the essential oils are made accessible to hydrolytic and fermentative bacteria that can metabolize them, converting the previously inhibitory substances into useful intermediates for biogas production
Solution Approach 2:
The patent converts the harmful effect of essential oils (which inhibit anaerobic digestion) into a beneficial effect. Through steam explosion pre-treatment, the essential oils are released and then metabolized by microorganisms in the bioreactor, transforming from inhibitors into substrates that contribute to biogas production, thus turning a harmful factor into a resource
4Duration of action of moving object
If storage of peel in equipped areas is performed for extended use, then anaerobic digestion can be sustained, but the management complexity increases
Solution Approach 1:
The patent uses steam explosion to rapidly transform the physical state of the citrus peel, creating a more stable, pre-treated material that can be stored without requiring complex environmental controls. The phase transition during steam explosion (heating, pressurization, and rapid cooling) stabilizes the material, allowing for simpler storage infrastructure while maintaining suitability for long-term biogas production
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 effectively converts citrus peels into a manageable aqueous solution with reduced organic content, suitable for biological purification and biogas production, while eliminating essential oils, thus addressing disposal and regulatory challenges.
Implementation Method 1
a first step consists in solubilizing the orange peels by means of a basic treatment at T = 150-250 °C
Implementation Method 2
a second step consists in the reduction of the pollutant load of peel previously solubilized by an oxidizing treatment in the presence of oxygen and of heterogeneous catalysts in bulk or supported on an inert support based on manganese and cerium (MnO2-CeO2, MnO2-CeO2-AC, etc.), at a temperature between 150 °C and 240 °C
Data Source
Figure 1
AI summary
A process is described for solubilizing residuals from squeezing citrus fruits (BA) comprising: a first step (101) of solubilizing residuals of squeezing citrus fruits (BA), wherein the solubilizing occurs: in a basic aqueous solution obtained through addition of an hydroxide or a basic salt; with different ratios between the amount of water and the amount of residuals of squeezing citrus fruits (BA); at a temperature between 30°C and 350°C; with reaction times between 3 hours and 24 hours; a second step (102) of catalytic oxidizing the residuals solubilized in the previous step (101), wherein the catalytic oxidizing occurs: at the presence of oxygen at a pressure between 2 bar and 50 bar; at the presence of at least one heterogeneous catalyst selected from the group comprising mixed metallic oxides and mixed metallic oxides supported by an inert support; at a temperature between 30°C and 350°C; with reaction times between 3 hours and 24 hours.