Countercurrent Trickle Bed Hydrogenation for Sugar Alcohol Production
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Solution Overview
Problem
Existing methods for producing sugar alcohols face challenges such as high hydrogen gas consumption, high pressure requirements, and low production efficiency, which hinder industrialization and increase costs.
Innovation Solution
A continuous gas-liquid countercurrent method using a trickle bed reactor with Raney nickel or Raney copper catalysts, where biomass sugar solution and hydrogen gas flow countercurrently through a catalyst bed to enhance mass transfer and reduce residence time, optimizing conditions like flow rates, pressures, and temperatures for improved conversion and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If batch hydrogenation is used in batch reactors, then catalysts are easily lost by mechanical agitation, but catalyst recovery becomes difficult
Solution Approach 1:
The patent uses a fixed-bed reactor configuration where the catalyst is immobilized on a support structure, acting as an intermediary between the liquid sugar solution and hydrogen gas. This allows the catalyst to remain stationary and easily recoverable while still facilitating the hydrogenation reaction effectively.
Solution Approach 2:
The patent extracts the catalyst from the moving liquid phase by fixing it in a stationary bed, separating the catalyst recovery function from the reaction process. This allows the catalyst to be easily removed and reused without being mixed with the product stream.
2Productivity
If high flow rates and high pressure are used to ensure thorough hydrogenation, then conversion rate improves, but hydrogen consumption and cost increase
Solution Approach 1:
The patent optimizes reaction parameters including using moderate hydrogen pressure (0.1-1.0 MPa) and controlled flow rates to achieve efficient hydrogenation without excessive hydrogen consumption. The fixed-bed configuration allows for optimized contact time between reactants and catalyst at lower pressures.
Solution Approach 2:
The continuous flow system ensures steady-state operation where hydrogen gas and sugar solution continuously pass through the catalyst bed, maintaining constant reaction conditions and efficient mass transfer without requiring high pressure spikes or excessive hydrogen flow rates.
3Productivity
If high pressure hydrogen gas is used, then hydrogenation efficiency improves, but safety issues and cost increase
Solution Approach 1:
The patent changes the pressure parameter from high pressure (8-17 MPa in prior art) to moderate pressure (0.1-1.0 MPa) while maintaining effective hydrogenation through the fixed-bed reactor design and optimized gas-liquid countercurrent flow, thereby eliminating safety risks associated with high-pressure hydrogen storage and handling.
4Manufacturing precision
If long residence time is used, then conversion is complete, but production efficiency decreases
Solution Approach 1:
The continuous flow system maintains steady-state operation where reactants continuously pass through the catalyst bed, achieving complete conversion within a short residence time. The constant flow ensures that fresh catalyst sites are continuously available, preventing the need for long batch processing times.
Solution Approach 2:
The fixed catalyst bed acts as an efficient intermediary that facilitates rapid hydrogenation reactions, allowing complete conversion to occur quickly as the liquid phase continuously contacts the catalyst surface, thereby reducing residence time while maintaining high conversion efficiency.
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 method significantly reduces hydrogen gas usage and pressure, enhances production efficiency, and maintains high conversion rates and yields of sugar alcohols, making it suitable for industrial-scale production.
Implementation Method 1
the biomass sugar solution and the hydrogen gas pass through a catalyst bed in a gas-liquid countercurrent manner for hydrogenation reduction to obtain a biomass sugar alcohol solution
Implementation Method 2
introducing hydrogen gas from a gas phase inlet to the trickle bed reactor from bottom to top, wherein the biomass sugar solution and the hydrogen gas pass through a catalyst bed
Implementation Method 3
the biomass sugar solution and the hydrogen gas pass through a catalyst bed in a gas-liquid countercurrent manner for hydrogenation reduction
Data Source
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AI summary
Provided is a method for continuous gas-liquid countercurrent preparing sugar alcohol, the method includes: in a gas-liquid countercurrent trickle bed reactor, pouring a biomass sugar solution from a liquid phase inlet into the trickle bed reactor from top to bottom, and introducing hydrogen gas from a gas phase inlet to the trickle bed reactor from bottom to top; the biomass sugar solution and the hydrogen gas pass through a catalyst bed in a gas-liquid countercurrent manner for hydrogenation reduction to obtain a biomass sugar alcohol solution. By highly efficiently intensifying the gas-liquid-solid three-phase mass transfer and shortening the residence time, the method for continuous gas-liquid countercurrent preparing sugar alcohol provided by the present disclosure realizes the continuous hydrogenation of the biomass sugar solution, and substantially improves the conversion rate of the biomass sugar and the yield of the corresponding sugar alcohol.