Biomass Pretreatment for Anaerobic Digestion Efficiency
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Solution Overview
Problem
Anaerobic digestion for energy valorization of biomasses is expensive and inefficient due to the progressive decrease in efficiency as volatile solids content increases, leading to reduced energy efficiency.
Innovation Solution
A method involving dilution of biomass with a thinner, followed by alkalization with a sodium hydroxide solution, hydrolysis at controlled temperatures, and neutralization using CO2 diffusion to enhance solubility and digestibility, resulting in high-purity biomethane production with low CO2 content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the volatile solids content in biomass is increased to improve energy density, then the energy content per volume increases, but the anaerobic digestion efficiency progressively decreases
Solution Approach 1:
The patent applies preliminary thermal treatment (heating to 80-90°C for 30-60 minutes) and alkaline treatment (pH 11-13) to the biomass before anaerobic digestion. This pre-treatment breaks down complex structures and solubilizes organic matter, making the volatile solids more accessible and digestible to microorganisms, thereby maintaining high digestion efficiency even with high volatile solids content biomass
2Productivity
If thermochemical hydrolysis is performed at high total solid content to reduce water usage, then process simplicity improves, but the efficiency of hydrolysis treatment decreases significantly
Solution Approach 1:
The patent changes the pH parameter to alkaline conditions (pH 11-13) and maintains moderate total solid content (5-20%) during thermochemical hydrolysis. This alkaline environment enhances the solubilization of organic matter and improves hydrolysis efficiency. The controlled solid content ensures sufficient heat and mass transfer while maximizing the breakdown of complex organic compounds into digestible forms
3Device complexity
If anaerobic digestion is performed without pre-treatment to simplify the process, then device complexity is reduced, but the energy efficiency and digestibility of biomass are insufficient
Solution Approach 1:
The patent implements a two-step pre-treatment process: thermal treatment (heating to 80-90°C for 30-60 minutes) followed by alkaline treatment (adjusting pH to 11-13). These preliminary actions solubilize organic matter, break down complex structures, and make biomass more digestible, significantly improving energy efficiency without requiring complex equipment
Solution Approach 2:
The patent utilizes parameter changes (temperature to 80-90°C and pH to 11-13) to enhance biomass digestibility. These parameter adjustments are achieved through simple heating and chemical addition, avoiding complex equipment while dramatically improving the energy efficiency of subsequent anaerobic digestion
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
Significantly increases anaerobic digestibility and energy efficiency, achieving over 100% performance with reduced energy consumption and improved biogas production.
Implementation Method 1
iii-3. Alkalizing the biomass of step iii-2 with a basic solution
Implementation Method 2
iv. hydrolyzing the mixture under application of heat, thereby obtaining a hydrolyzed biomass
Implementation Method 3
The former appears to be very promising since permits to solubilize up to 70% of the total solids forming the biologic sludges
Implementation Method 4
v. neutralizing the hydrolyzed biomass through diffusion of CO 2 from a biogas produced by anaerobic digestion
Implementation Method 5
vi. Performing anaerobic digestion, through a first anaerobic digestor of said hydrolyzed and neutralized sludge, thereby obtaining a biogas
Data Source
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AI summary
The present invention relates to a process for the treating and generating energy from biomass and a plant where the process is implemented, said process comprising the steps of (i) providing a biomass (1), and characterized by comprising the steps of: (ii) diluting the biomass (1) with a thinner up to a volatile solids content comprised between 0.5% and 1% of the volume of said biomass (1); (iii) alkalizing the biomass (1) of item ii with a basic solution (3), up to a pH comprised between 11.0 and 13.0, wherein said biomass (1) of item ii and said basic solution (3) are in a weight ratio comprised between 1 :20 and 1 :80; (iv) hydrolysing the alkalised biomass of item iii, for a time comprised between 30 and 90 minutes, at a temperature comprised between 55°C and 80°C, thereby obtaining a hydrolysed biomass (4); (v) neutralising the hydrolysed biomass (4) of item iv, through diffusion of C02 from a biogas produced by anaerobic digestion, thereby obtaining a hydrolysed and neutralised sludge (5); (vi) performing anaerobic digestion, through a first anaerobic digestor (6), of said hydrolysed and neutralised sludge (5), thereby obtaining a biogas (60), a first digestate (61), an anaerobic sludge (62).