Pyrolysis Reactor Mixer for Cyclone-Free Biomass Separation
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Solution Overview
Problem
Existing pyrolysis reactors face issues with clogging due to fine carbon particles accumulating in separating cyclones, leading to blockages, especially when dealing with biomass and tacky solid materials.
Innovation Solution
The reactor design incorporates a mechanical mixer and a configuration that ensures the average velocity of pyrolysis gas and entrained materials is comparable to their terminal falling velocity, allowing for substantial separation of pyrolysis gas and solid materials under gravitational force without a cyclone, preventing clogging by directing solid materials primarily through a second discharge and gas through a first discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cyclone separator is used to separate pyrolysis gas from solid particles, then separation efficiency is improved, but the cyclone becomes clogged by fine carbon particles over time
Solution Approach 1:
The invention extracts the harmful fine carbon particles from the gas stream at the source (in the reactor space) before they can reach and clog the cyclone separator. By using a mixer with controlled velocity to separate particles gravitationally in the reactor space itself, the particles are removed from the flow that would otherwise enter the cyclone, thus preventing clogging while maintaining continuous operation.
Solution Approach 2:
The mixer in the reactor space acts as an intermediary separation device between the pyrolysis zone and the cyclone separator. By controlling the mixer velocity to match terminal falling velocity, it creates a gravitational separation zone that intercepts fine particles before they proceed to the cyclone, serving as a protective intermediary that prevents the cyclone from becoming clogged.
2Productivity
If the reactor velocity is increased to improve gas flow, then productivity is improved, but separation of solid particles from gas deteriorates
Solution Approach 1:
The invention changes the velocity parameter of the mixer to match the terminal falling velocity of the particles. This specific parameter setting creates optimal conditions where particles can separate from the gas flow under gravitational influence while maintaining sufficient gas flow for productivity. The velocity is neither too high (which would prevent separation) nor too low (which would reduce productivity).
3Reliability
If a mechanical mixer is introduced to control particle velocity, then particle-gas separation is improved, but device complexity increases
Solution Approach 1:
The mixer serves multiple functions: it mixes the biomass and heat carrier material for efficient heat transfer, it controls the velocity of the particle-gas mixture to enable gravitational separation, and it acts as a separation device itself by allowing particles to settle. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
4Reliability
If the reactor space is modelled to block direct flow, then separation efficiency is improved, but pressure loss increases
Solution Approach 1:
The reactor space is designed to create a flow pattern where the gas and particles move through a controlled path that allows gravitational separation to occur. By modelling the reactor space to block direct flow, the invention creates conditions where particles can settle under gravity while the gas continues to flow, achieving separation without requiring additional energy input for complex separation mechanisms.
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 design effectively prevents clogging and ensures efficient separation of solids from pyrolysis gas, with all solid particles being separated in the reactor's mixer region, allowing for continuous operation without cyclone-induced blockages.
Implementation Method 1
a mechanical mixer is present in the reactor space for the purpose of mixing the incoming flow of biomass material with the incoming flow of preheated heat carrier material
Implementation Method 2
the maximum average velocity v of the pyrolysis gas and the thereby entrained material in the reactor space downstream of the mixer at a temperature in the range of about 400°C - 550°C is about as great as the terminal falling velocity, such that at least a substantial separation between the discharge flows of respectively pyrolysis gas and solid material takes place predominantly, and in any case for more than 50%, under the influence of gravitational force
Implementation Method 3
an at least more or less vertical baffle is situated in the reactor space which connects to the upper wall of the reactor space, whereby the flow from the mixer, comprising a mixture of pyrolysis gas and solid material, and/or the part-flows of pyrolysis gas and solid material can only reach respectively the first discharge and the second discharge by passing over the lower edge of the baffle
Data Source
Figure 1~4
AI summary
A device for pyrolysing biomass comprises: a reactor space; a first feed for biomass material connecting to the upper zone thereof; a second feed for heated heat carrier material connecting to the upper side of the reactor space; a first discharge for pyrolysis gas connecting to the upper zone of the reactor space at a distance from the first feed; and a second discharge for solid material, for instance carbon and heat carrier material, connecting to the underside of the reactor space. A substantial separation between the discharge flows of pyrolysis gas and solid material takes place predominantly under the influence of gravitational force, without interposing of a cyclone. The reactor space is modelled such that the direct flow from the first feed and the second feed to the first discharge is blocked. A mechanical mixer is present in the reactor space for the purpose of mixing the flow of biomass material with the flow of preheated heat carrier material.