Dual Bed Gasification System Tar Management
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Solution Overview
Problem
Circulating fluidized-bed-thermal decomposition poly-generation technologies face issues with tar separation leading to blockages and corrosion, and rely heavily on boiler heat, limiting system reliability and stability.
Innovation Solution
A solid fuel grade gasification-combustion dual bed poly-generation system incorporating a circulating fluidized-bed combustion boiler, a gasification boiler, a synthesized gas purification unit, and a methanation unit, where the system integrates fuel utilization through dual fluidized-beds, steam generation, and methanation to produce clean energy products, including electricity, heat, and natural gas, with ash recycling and tar utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thermal decomposition technology is used for poly-generation, then electricity and synthesized gas can be produced, but tar separation becomes difficult causing blockage and corrosion to pipes and valve systems
Solution Approach 1:
The patent converts the harmful tar byproduct into a useful fuel resource. The tar collected from the gasification process is burned in a dedicated tar burning chamber to generate heat, which is then used to produce steam. This transforms the harmful tar into a beneficial energy source, eliminating the blockage and corrosion problems while providing additional steam for the poly-generation system.
Solution Approach 2:
The patent extracts and removes the tar from the synthesized gas stream through a condensation and separation system. By cooling the synthesized gas, tar condenses and is separated from the gas phase, allowing the clean gas to proceed to power generation while the tar is directed to the burning chamber for energy recovery.
2Productivity
If thermal decomposition system excessively depends on boiler heat, then poly-generation can be achieved, but system reliability and stability are seriously affected
Solution Approach 1:
The patent segments the thermal decomposition process into two distinct boilers: a gasification boiler that produces synthesized gas and a combustion boiler that produces steam. This segmentation allows each boiler to operate independently with optimized conditions, improving system reliability while maintaining poly-generation capability through the coordination of both units.
Solution Approach 2:
The patent changes the operational parameters by introducing a dual-boiler system with different heating conditions. The gasification boiler operates with controlled oxygen input for partial oxidation, while the combustion boiler operates with excess oxygen for complete combustion. This parameter differentiation enables stable operation and improves system reliability while maintaining high poly-generation output.
3Loss of energy
If dual fluidized-beds are integrated for combustion and gasification, then complete fuel utilization is achieved, but device complexity increases
Solution Approach 1:
The patent merges the combustion and gasification processes into an integrated dual-fluidized-bed system. Both boilers share common fuel feeding mechanisms, ash handling systems, and steam generation networks. This merging approach achieves complete fuel utilization by processing different portions of fuel through complementary processes while minimizing the increase in device complexity through shared infrastructure.
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
The system achieves stable and efficient operation, complete fuel utilization, reduced tar yield, improved gasification efficiency, and enhanced product utilization, addressing the limitations of existing technologies by integrating combustion and gasification processes and utilizing steam and CO2 as gasifying agents.
Implementation Method 1
The heat generated during combustion is used to produce steam
Implementation Method 2
A gasifying agent for gasification is sent into the gasification boiler fluidizing air inlets and then flows into the circulating fluidized-bed gasification boiler
Implementation Method 3
flue gas generated during combustion enters at least a primary combustion boiler cyclone separation unit
Implementation Method 4
The methanation unit converts the fed synthesized gas into synthesized natural gas
Implementation Method 5
uses water as a cooling media to cool the synthesized gas in a heat exchange mode
Implementation Method 6
the oil-water separation occurs on at least one part of the sewage generated during cooling
Data Source
AI summary
The present invention demonstrates a solid fuel grade gasification-combustion dual bed poly-generation system, comprising a combustion system, a gasification system, a synthesized gas cooling and purifying system and a synthesized gas methanation system. The combustion system is connected with the gasification system through a circulating material return system. The gasification system mainly adapts the circulating fluidized-bed combustion mode. The gasification system adapts the fluidized-bed incomplete gasification method and the generated semi-coke is returned to the combustion system for re-utilization. The synthesized gas purifying and cooling unit adapts water cycling and combustible recycling. The by-products, CO2 and steam, in the methanation unit can be recovered, so the maximum utilization rate of energy in this system is realized.