Biomass Gasification via Hydrothermal Carbonization
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Solution Overview
Problem
Current biomass gasification processes face inefficiencies in energy conversion, equipment complexity, and flexibility issues, particularly in producing tar-free, low-methane, carbon monoxide, and hydrogen-rich synthesis gas, especially when dealing with inferior biomass like green clippings and agricultural waste.
Innovation Solution
A device and method utilizing hydrothermal carbonization to convert biomass into a high-energy-density carbonization char, which is then dried, ground into a suitable dust, and fed into an entrained flow gasification system, allowing for high-temperature, high-pressure processing with reduced energy input and equipment complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fluidized bed gasification is used to process biomass, then the process can handle various biomass types with relatively simple equipment, but the gas produced contains high tar and methane content requiring additional separation equipment
Solution Approach 1:
The gasification process is divided into two distinct stages: a first gasification stage operating at lower temperatures to convert biomass into NTV gas and coke, followed by a second high-temperature gasification stage that processes the coke to produce tar-free synthesis gas. This segmentation allows each stage to be optimized for its specific function, with the first stage handling biomass conversion and the second stage eliminating tars through high-temperature processing.
Solution Approach 2:
NTV gas and coke produced in the first gasification stage serve as intermediaries that are transferred to the second gasification stage. The NTV gas provides carbon monoxide and hydrogen to the second stage, while the coke serves as both fuel and carbon source. This intermediary approach allows the system to achieve tar-free synthesis gas by processing the intermediate products through high-temperature gasification.
2Object-generated harmful factors
If high-temperature entrained flow gasification is used to eliminate tars, then tar-free synthesis gas is produced, but the process requires complex equipment for solids transfer and operates at high pressure increasing equipment complexity
Solution Approach 1:
The process separates biomass processing from synthesis gas production into two distinct gasification stages. The first stage handles biomass conversion at lower temperatures, producing NTV gas and coke that can be conveyed to the second stage. This segmentation reduces the need for complex high-pressure solids handling equipment throughout the entire process, as only the second stage operates at high pressure.
Solution Approach 2:
The harmful tar components are extracted and eliminated in the second high-temperature gasification stage, where coke is gasified at temperatures above the ash melting point. This extraction of tars in a dedicated high-temperature zone allows the first stage to operate with simpler equipment, and the high-pressure synthesis gas production to occur only in the final stage.
3Loss of energy
If Carbo-V gasification process is used to achieve high conversion efficiency, then cold gas efficiency approaches fluidized bed gasification levels, but the process requires extensive solids transfer operations including crushing and conveying
Solution Approach 1:
The two-stage gasification process segments the conversion operations so that the first stage produces NTV gas and coke at lower temperatures with less stringent particle size requirements. The second stage then processes the coke at high temperatures to achieve high conversion efficiency and tar elimination. This segmentation reduces the need for extensive crushing and solids transfer equipment compared to single-stage high-temperature gasification.
Solution Approach 2:
The first gasification stage performs preliminary conversion of biomass into NTV gas and coke, preparing the material for the second stage. This preliminary action occurs at lower temperatures and pressure, requiring less complex equipment for material handling and preparation, while still achieving high overall conversion efficiency when combined with the second stage.
4Device complexity
If direct coupling of NTV reactor and entrained flow gasification is used, then process integration is achieved, but spatial and temporal separation of biomass processing and gasification is lost reducing flexibility
Solution Approach 1:
The process is segmented into two independent gasification stages that can operate semi-independently. The first stage processes biomass into NTV gas and coke, which can then be conveyed to the second stage. This segmentation allows for spatial and temporal separation, enabling the first stage to continue producing intermediates even if the second stage requires maintenance or adjustment, thereby increasing overall process flexibility and availability.
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 enhances energy efficiency, carbon utilization, and flexibility, enabling the production of tar-free, low-methane, carbon monoxide and hydrogen-rich synthesis gas with higher throughput and lower production costs compared to existing methods.
Implementation Method 1
the biomass is converted into a carbonization char in a carbonization reactor by hydrothermal carbonization at temperatures of 180-230 °C and a pressure of 20-30 bar
Implementation Method 2
the carbonization char is gasified in a high-temperature, high-pressure entrained flow gasification process to produce a fuel, synthesis or reducing gas
Implementation Method 3
the resulting NTV gas containing tar is exothermically gasified with the residual coke from dry gas cleaning in a high-temperature entrained flow gasification process at temperatures above the ash melting point
Implementation Method 4
the gasification gas cools down to approx. 800 to 900 °C
Data Source
Figure 1
AI summary
The present invention relates to a device for generating a synthesis gas (SG) from biomass (BM) by entrained-flow gasification. The device comprises a processing unit (1) in which the biomass (BM) is fed to a coarse comminuting device (2) which is connected downstream via a first sluice (3) to a pressurized carbonization unit (4) for the hydrothermal generation of carbonization coal (KK) from the biomass (BM). The carbonization unit (4) comprises at least one preheating device (5) and a carbonization reactor (6) that is arranged downstream of the preheating device (5) and is connected downstream via a second sluice (11) to at least one solid-liquid separation device (12, 13) for providing a fuel. Downstream of the solid-liquid separation device (12, 13), a drying device (16) for drying the fuel is provided, downstream of which is connected a comminution device (18) for comminuting the fuel into a combustible dust (BS) having particle sizes in a range from 55 µm to 500 µm. The device further comprises a transfer device (21) for transferring the fuel into an entrained-flow gasification unit (22), in such a manner that the processing unit (1) is coupled to the entrained-flow gasification unit (22). In addition, the present invention discloses a method for generating a synthesis gas (SG) from biomass (BM) by entrained-flow gasification, using a device according to the invention.