Fluidized Bed Reactor Hydropyrolysis Temperature Control
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Solution Overview
Problem
Conventional fluidized bed reactors face challenges in maintaining temperature control and ensuring adequate heating and dispersion of biomass feedstock during hydropyrolysis, leading to operability issues and reduced yield of desired products.
Innovation Solution
The process involves supplying a biomass feedstock, hydrogen fluidizing gas, and a deoxygenating catalyst to a fluidized bed reactor with a mixing zone and a bulk reactor zone, where the biomass is rapidly heated and dispersed in the catalyst, producing a hydropyrolysis reactor output comprising non-condensable gases, partially deoxygenated products, and char.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fluidized bed reactor operates at minimum inlet temperature to prevent operability issues, then reactor inlet temperature is maintained, but reactor outlet temperature exceeds maximum allowable temperature due to exothermic heat generation
Solution Approach 1:
The reactor is divided into two distinct zones: a mixing zone at the bottom where biomass is introduced and rapidly heated, and a bulk reactor zone above where the hydropyrolysis reaction occurs. This segmentation allows different temperature conditions to prevail in different regions, preventing excessive outlet temperature while maintaining minimum inlet temperature for operability.
Solution Approach 2:
A catalyst recirculation stream acts as an intermediary, transferring heat from the hot bulk reactor zone back to the mixing zone. This heat transfer mechanism allows the system to maintain minimum inlet temperature without requiring excessive quench gas, thereby controlling outlet temperature while ensuring reliable operation.
2Temperature
If conventional fluidized bed reactor uses excessive quench gas or ballast gas to control outlet temperature, then reactor outlet temperature is reduced, but economic efficiency decreases
Solution Approach 1:
The system uses its own internal resources (catalyst recirculation stream) to control temperature rather than relying on external quench gas or ballast gas. The catalyst stream naturally circulates and transfers heat within the reactor, eliminating the need for additional cooling agents and improving economic efficiency while maintaining temperature control.
3Device complexity
If conventional fluidized bed reactor relies on natural heating and dispersion of biomass, then reactor structure is simple, but biomass heating rate and dispersion are insufficient leading to reduced pyrolysis yield
Solution Approach 1:
The mixing zone performs preliminary heating and dispersion of biomass before it enters the bulk reactor zone. By pre-heating the biomass in this dedicated zone using the catalyst recirculation stream, the system ensures rapid heating and adequate dispersion without adding complex mechanisms throughout the entire reactor, thereby maintaining simplicity while improving pyrolysis yield.
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 approach allows for efficient temperature management within the reactor, ensuring the minimum inlet temperature is maintained while preventing excessive outlet temperatures, and facilitates rapid heating and dispersion of the biomass, thereby enhancing the yield and quality of the hydropyrolysis products.
Implementation Method 1
a fluidized bed reactor for hydropyrolysis of a biomass feedstock
Implementation Method 2
contacting the biomass feedstock with a catalyst in the fluidized bed
Implementation Method 3
the heat generated by the exothermic hydrodeoxygenation reaction occurring inside the reactor
Implementation Method 4
hydropyrolysis of a biomass feedstock
Data Source
AI summary
A process includes a.) supplying a biomass feedstock, a fluidizing gas having hydrogen, and a catalyst recirculation stream having deoxygenating catalyst to a mixing zone of a fluidized bed reactor; b.) allowing the biomass feedstock, the fluidizing gas and the deoxygenating catalyst to move upwards through the fluidized bed reactor from the mixing zone to a bulk reactor zone; c.) allowing the biomass feedstock to contact the deoxygenating catalyst in the presence of the fluidizing gas in the bulk reactor zone of the fluidized bed reactor to produce a hydropyrolysis reactor output including at least one non-condensable gas, a partially deoxygenated hydropyrolysis product and char; and d.) withdrawing at least a portion of the deoxygenating catalyst from the bulk reactor zone to form the catalyst recirculation stream that is supplied to the mixing zone in step a).