Coarse Fluxing Agent Filter Conditioning in Gasification
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Solution Overview
Problem
The existing particulate filtration systems in gasification processes face inefficiencies due to deep infiltration of char particles into filter elements, leading to increased back-pulse gas pressure, reduced filter lifespan, and decreased operational availability, as well as the need for premixing fluxing agents with carbonaceous feedstock, which reduces gasification efficiency.
Innovation Solution
Introducing a selectively-sized, coarse fluxing agent into the raw synthesis gas stream upstream of the particle filtration device to condition the filter elements, preventing deep penetration of char particles and allowing for easier removal, while recycling the fluxing agent and char back to the gasification reactor to eliminate the need for premixing and enhance carbon conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If back-pulsing is used to remove filter cake, then filter element permeability is restored, but small particles trapped within pores are not effectively dislodged and infiltration decreases lifespan
Solution Approach 1:
The patent applies preliminary action by introducing a coarse particulate fluxing agent into the synthesis gas stream before it enters the filter elements. This fluxing agent pre-conditions the filter elements by filling pores and creating a protective layer, preventing fine char particles from penetrating deeply into the filter media. This preliminary protection reduces the need for high back-pulse pressures and extends filter element lifespan.
2Reliability
If filter elements are replaced, then filtration efficiency is restored, but new filters have increased permeability to char particles requiring conditioning time that decreases operating availability
Solution Approach 1:
The coarse particulate fluxing agent is introduced immediately upon filter element installation, performing preliminary conditioning action. The fluxing agent particles are larger than filter pores and deposit on the filter surface, creating an immediate protective layer that prevents fine particle infiltration. This eliminates the need for extended conditioning periods and restores full operating availability immediately.
Solution Approach 2:
The fluxing agent acts as an intermediary substance between the synthesis gas stream and the filter elements. It mediates the interaction by forming a protective interface layer that prevents direct contact between fine char particles and filter pores, thereby protecting the filter elements while maintaining operational productivity.
3Reliability
If fluxing agent is premixed with carbonaceous feedstock, then ash fusion temperature is reduced and slag viscosity decreases, but overall gasification efficiency is reduced due to mixing step and reduced feedstock addition rate
Solution Approach 1:
The patent extracts the fluxing agent addition step from the feedstock preparation process. Instead of premixing fluxing agent with carbonaceous feedstock, the fluxing agent is introduced separately into the synthesis gas stream downstream of the gasifier. This separation eliminates the mixing step constraint and allows maximum feedstock addition rates while still achieving the desired slag fluidity benefits.
Solution Approach 2:
The fluxing agent is continuously introduced into the synthesis gas stream at the optimal point downstream of the gasifier. This continuous addition ensures consistent slag conditioning without interrupting the feedstock gasification process, maintaining continuous high-rate feedstock addition while achieving reliable slag drainage.
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 extends filter element lifespan by reducing differential pressure and improves gasification efficiency by maintaining permeability, allowing for increased carbon feedstock rate and efficient slag drainage, while minimizing the time required for filter conditioning.
Implementation Method 1
depositing a thin layer of the fluxing agent onto and within the pores the filter elements, thereby conditioning the filter elements and decreasing the subsequent permeability of the filter elements to entrained char particles
Implementation Method 2
A cyclone creates a vortex of gas that facilitates the removal of a large percentage of the entrained particulate matter
Implementation Method 3
directing a periodic pulse of high-pressure gas backwards through the filter elements (known as 'back-pulsing') in order to dislodge at least a portion of the accumulated filter cake
Implementation Method 4
the addition of certain minerals to the gasification reactor reduces the fusion temperature of the ash generated by the gasification of carbonaceous material. A reduction in the ash fusion temperature decreases the viscosity of the mineral slag formed during gasification
Data Source
Figure 1
AI summary
Improvements in a gasification system and process for gasifying carbonaceous feedstock with improved energy efficiency. Improved methods and systems for more efficient removal of particulates from a raw synthesis gas while simultaneously providing a novel mechanism for fluxing agent addition to the gasification reactor. A conditioning agent, in the form of coarse fluxing agent particles, is added to the raw synthesis gas upstream from the particle filtration unit. The contitioning agent allows more rapid turnaround of the filtration unit following filter element replacement, extend filter life, facilitates the removal of filter cake from the particle filters, and combines with removed filter cake for recycling to the gasifier. Addition of fluxing agent via this route eliminates the need to premix fluxing agent with the carbonaceous feedstock, thereby maximizing the rate of feedstock addition to the gasification reactor.