Scraping Device for Lignocellulosic Biomass Pretreatment Reactor
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Solution Overview
Problem
The formation of deposits on the interior walls of reactor vessels during lignocellulosic biomass pretreatment reduces reactor efficiency and requires frequent shutdowns, leading to increased production costs and reduced sugar yields.
Innovation Solution
A pretreatment arrangement with a scraping device having a shaft and blades that rotate along the reactor's longitudinal center line, scraping deposits without contacting the walls, combined with a gas valve to manage pressure fluctuations and a sluice vessel for controlled biomass discharge, ensuring a stable and efficient pretreatment process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If biomass is pretreated in a closed reactor vessel at elevated temperatures and pressures, then the cellulose becomes increasingly accessible to cellulolytic enzymes and sugar yields improve, but deposits form on the interior walls of the reactor reducing reactor efficiency and capacity
Solution Approach 1:
The scraping device performs preliminary action by continuously removing deposits before they can accumulate to problematic levels. The rotating scraping blades constantly contact the reactor interior walls to prevent deposit buildup, ensuring the reactor maintains full capacity and operational stability throughout the pretreatment process.
Solution Approach 2:
The scraping device is configured to be self-regulating, where the deposit layer itself guides the scraping action. As deposits form on the interior walls, the scraping blades automatically engage with them through the flexible membrane's contour-following mechanism, eliminating the need for separate deposit detection or intervention systems.
2Reliability
If a scraping device with shaft extending into the lower portion of the reactor is used, then deposits can be scraped from the walls, but the shaft itself becomes a surface for deposit formation and reduces the effective reactor volume
Solution Approach 1:
The invention extracts the shaft from the lower portion of the reactor vessel, eliminating the problematic element that caused deposit formation. The scraping blades are supported entirely within the upper portion, removing the shaft's interference with the liquid phase and its role as a deposit-nucleating surface, thereby maximizing effective reactor volume.
Solution Approach 2:
The scraping device transitions from a three-dimensional shaft extending into the liquid phase to a two-dimensional blade assembly that follows the contour of the reactor walls. This dimensional change allows the scraping function to be performed without occupying reactor volume or interfering with the biomass processing space.
3Reliability
If the scraping blades contact the interior walls of the reactor, then deposits can be effectively removed, but the blades may damage the reactor walls or become clogged with deposits
Solution Approach 1:
The scraping blades are constructed as flexible membranes that conform to the reactor's interior contour. This flexibility allows the blades to maintain continuous contact with the walls for effective deposit removal while accommodating surface irregularities and preventing concentrated stress points that could cause wall damage or blade clogging.
Solution Approach 2:
The scraping blades are designed with curved surfaces that match the cylindrical contour of the reactor interior. This curvature ensures uniform distribution of scraping pressure along the wall surface, preventing localized overheating or mechanical damage to the reactor walls while maintaining consistent deposit removal efficiency.
Data Source
AI summary
The present disclosure generally relates to a pretreatment arrangement (100) for pretreatment of lignocellulosic biomass comprising a reactor vessel (101) extending along a longitudinal center line (102) and having an upstream inlet (103) for receiving biomass and a downstream outlet (104) for discharging biomass. The pretreatment arrangement (100) further comprising a scraping device (108) configured to scrape the interior walls (111) of the reactor vessel (101) and prevent the formation and build-up of deposits.