Multi-stage Condensation for Biomass Pyrolysis Slurry Stability
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Solution Overview
Problem
The existing methods for producing rapid pyrolysis products from biomass for entrained flow pressure gasification face challenges such as instability and segregation of slurry components during storage and transport, leading to safety risks and logistical difficulties in large-scale applications.
Innovation Solution
A method involving multi-stage condensation to separate pyrolysis products, where smoldering tar is condensed above the dew point and smoldering water is separated between 0°C and the dew point, followed by mixing the stable components into a homogeneous slurry just before gasification, ensuring a consistent composition and reducing the risk of segregation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pyrolysis products are mixed into a slurry for transport and storage, then they can be easily handled and transported, but the slurry becomes unstable and undergoes segregation during storage and transport
Solution Approach 1:
The patent applies segmentation by separating the pyrolysis condensate into different fractions based on their properties. The condensate is divided into a water-soluble fraction and an organic fraction, which are then handled and transported separately or in controlled combinations, preventing the segregation that occurs when all components are mixed into a single unstable slurry.
Solution Approach 2:
The patent utilizes parameter changes by controlling the temperature during condensation and separation processes. By condensing the pyrolysis vapors at specific temperature ranges and adjusting the phase state of different components, the method enables stable separation and handling of pyrolysis products, transforming the unstable slurry into stable, transportable fractions.
2Duration of action of stationary object
If the slurry is stored for extended periods, then transport logistics are improved, but phase separation occurs with formation of aqueous and organic phases
Solution Approach 1:
The patent applies preliminary action by performing separation of the pyrolysis condensate into stable fractions before storage and transport. By pre-separating the condensate into water-soluble and organic fractions with different storage characteristics, the method enables each fraction to be stored for extended periods without the phase separation problems that affect mixed slurries.
3Stability of the object's composition
If aqueous phase separates with low calorific value, then storage stability is reduced, but excessive oxygen occurs in the gasifier leading to explosion risks
Solution Approach 1:
The patent uses an intermediary approach by introducing a separation and control system between the pyrolysis process and the gasifier. The condensate is separated into controlled fractions, and the composition is regulated before entering the gasifier, preventing the formation of low-calorific aqueous phases that could cause oxygen excess and explosion risks in the gasification process.
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 results in stable and transportable pyrolysis products that can be easily mixed into a homogeneous slurry, reducing the risk of explosions and improving the safety and efficiency of biomass gasification by maintaining a consistent composition and preventing phase separation.
Implementation Method 1
Fast pyrolysis is used to convert carbon-containing feedstocks such as biomass into a lot of liquid pyrolysis condensate (pyrolysis oil) and a little solid pyrolysis coke and pyrolysis gas
Implementation Method 2
The pyrolysis vapors are condensed in several condensation stages, with separation of one component at each condensation stage
Implementation Method 3
smoldering tar is condensed above the dew point and smoldering water is separated between 0°C and the dew point
Data Source
AI summary
Process for production and preparation of rapid pyrolysis products from biomass for pressurized entrained-flow gasification comprising heating the biomass in the absence of oxygen in a pyrolysis reactor, in which process a temperature between 400 and 600°C is established for one to 50 seconds and the biomass reacts to form porous pyrolysis coke, pyrolysis condensate and pyrolysis gas, the pyrolysis gases are removed and vaporous components of the pyrolysis condensate are condensed in a plurality of condensation stages, condensed components being separated off in each condensation stage. The object is to improve the process in such a manner that, in particular, the risk of unwanted separation of the pyrolysis condensate and/or slurry before entry into the pressurized entrained-flow gasifier is reduced. The object is achieved by a means that in the first condensation stage a coke-condensate mixture is separated off at temperatures above the dew point of water, and in at least one following condensation stage an aqueous solution, called low-temperature carbonization wastewater, of oxygenated organic compounds is condensed and separated at temperatures between 0°C and 90°C.