Semi-Continuous Sludge Hydrolysis Reactor Pressure Control
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Solution Overview
Problem
Current thermal hydrolysis processes for sludge treatment are complex, costly, and inefficient, with issues such as reactor clogging, high steam consumption, and limited dryness of treated sludge, while also requiring extensive maintenance and multiple treatment lines.
Innovation Solution
A semi-continuous thermal hydrolysis process that pressurizes sludge to 2-16 bar, injects live steam to 120-200°C, and applies a thermal hydrolysis cycle in parallel reaction spaces without steam injectors, using a common gas overhead for pressure balancing and reduced equipment complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If steam injectors are installed in thermal hydrolysis reactors to distribute steam at several points, then steam distribution efficiency is improved, but device complexity and construction cost increase due to multiple gateways
Solution Approach 1:
The invention removes steam injectors from the reactor system entirely. Instead of installing multiple injectors throughout the reactor height, the system uses a single steam injection point at the top of the reactor, allowing steam to distribute naturally through the sludge column without requiring complex injector infrastructure or multiple gateways for maintenance
Solution Approach 2:
The invention segments the thermal hydrolysis process into three independent reaction spaces operating in parallel with staggered cycles. This allows continuous sludge treatment while simplifying each individual reactor's steam injection requirements, as each reactor handles a discrete batch rather than requiring continuous steam distribution throughout
2Productivity
If multiple thermal hydrolysis reactors operate in parallel with staggered cycles, then continuous sludge treatment is achieved, but equipment complexity and investment cost increase
Solution Approach 1:
The system divides the continuous treatment requirement into three separate reaction spaces that operate in parallel with staggered batch cycles. Each reactor treats discrete batches sequentially, but the combined output of all three reactors provides continuous sludge treatment capability, maintaining productivity while simplifying individual reactor design
Solution Approach 2:
By staggering the operational cycles of the three reaction spaces, the system ensures that while one reactor is in the heating phase, another is in the reaction phase, and a third is in the discharge phase. This continuous cycling of different reactors maintains uninterrupted sludge treatment without requiring complex coordination or additional equipment
3Loss of energy
If flash steam is injected into sludge bed through steam injector, then heat recovery efficiency is improved, but pressure drops increase due to injector configuration and sludge height
Solution Approach 1:
Instead of injecting steam from the bottom up through the sludge bed (which causes pressure drops), the invention inverts the approach by injecting steam from the top down. Flash steam is introduced at the top of the reactor and flows downward through the sludge column, utilizing gravity to maintain pressure while still achieving effective heat transfer and hygienization
4Reliability
If reactors are equipped with multiple gateways for steam injector maintenance, then steam injection reliability is improved, but ease of manufacture and construction cost worsen
Solution Approach 1:
The invention completely removes steam injectors from the reactor system, eliminating the need for multiple gateways and complex maintenance infrastructure. A single steam injection point at the top of the reactor provides sufficient steam distribution without requiring removable components or specialized access points, greatly simplifying reactor construction and maintenance
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 ensures efficient sludge treatment with reduced equipment complexity, lower steam consumption, and higher dryness of treated sludge, while maintaining hygienization and solubilization effectiveness, and allows continuous sludge handling with fewer maintenance needs.
Implementation Method 1
the pressurization of sludge to be treated at a reference pressure of between 2 bar a and 16 bar a
Implementation Method 2
the injection of live steam into said pressurized sludge so as to bring the temperature thereof between 120°C and 200°C
Implementation Method 3
a gaseous headspace common to said at least three reaction spaces being provided, and the pressure in said common gas headspace being measured and maintained substantially constant at said reference pressure
Implementation Method 4
maintaining said batch of sludges in said reaction space for a time sufficient for its thermal hydrolysis
Implementation Method 5
transform the organic matter they contain into easily biodegradable soluble matter
Data Source
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AI summary
A process for thermal hydrolysis of sludge, comprising: the pressurization of sludge to be treated (2) at a reference pressure between 2 bar a and 16 bar a, the injection of live steam (3) into said pressurized sludge so as to bring the temperature thereof to between 120°C and 200°C, the application to the sludge of a thermal hydrolysis cycle consisting in: a) conveying a sludge batch into a reaction space (7a, 7b, 7c); b) maintaining the sludge batch in said reaction space (7a, 7b, 7c) for a period sufficient for thermal hydrolysis thereof; and c) emptying said sludge batch out of said reaction space, the depressurization (10) of the hydrolized sludge and the discharge thereof (11), the application to the sludge of a thermal hydrolysis cycle being carried out in parallel in at least three reaction spaces (7a, 7b, 7c), in each of which a succession of treatment cycles is carried out, each of the reaction spaces being dedicated to the treatment of distinct sludge batches, steps a), b), and c) of said treatment cycles being offset in time from one reaction space to the other, a gaseous headspace common (12) to said at least three reaction spaces being controlled, and the pressure reigning in this common gaseous headspace being measured (15) and kept essentially constant at the reference pressure. A facility for carrying out this process.