Steam-Exploded Biomass Fuel Additives for Heat Transfer Surface Protection
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Solution Overview
Problem
The co-firing of biomass with coal in power plants leads to increased slagging and fouling of furnaces and heat exchangers, along with corrosion of heat transfer surfaces due to the chemical and mechanical effects of flue gases, which reduces heat transfer efficiency and shortens equipment lifespan.
Innovation Solution
Steam explosion treatment of biomass followed by the addition of suitable combustion additives to the biomass-based fuel, which simplifies grinding and reduces fouling and corrosion on heat transfer surfaces by altering the ash melting point and chemical composition of flue gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If biomass is co-fired with coal, then renewable energy production is improved, but fouling and slagging of heat transfer surfaces worsen
Solution Approach 1:
The biomass undergoes steam explosion treatment before combustion to pre-modify its structure and reduce fouling potential. This preliminary action breaks down the biomass structure and removes substances that would otherwise cause severe fouling during co-firing with coal
Solution Approach 2:
The invention changes the chemical composition parameters of the biomass fuel by adding specific additives (such as calcium compounds, magnesium compounds, or silicon compounds) that modify the ash melting point and chemical reactivity, thereby reducing fouling and slagging on heat transfer surfaces
2Productivity
If biomass is ground to fine powder, then combustion efficiency is improved, but energy consumption and equipment wear worsen
Solution Approach 1:
Steam explosion treatment is applied to biomass before grinding to pre-fragment the material structure. This preliminary action makes the biomass more brittle and easier to grind, reducing the energy required for size reduction while still achieving the fine powder necessary for efficient combustion
3Ease of manufacture
If steam explosion treatment is applied to biomass, then grindability is improved, but process complexity worsens
Solution Approach 1:
The steam explosion treatment is implemented as a preliminary step in the biomass preparation process. By performing this treatment before grinding and combustion, the process leverages the improved grindability of steam-exploded biomass while integrating the complexity into a standardized pre-treatment stage
4Reliability
If combustion additives are added to biomass, then corrosion resistance of heat transfer surfaces is improved, but fuel preparation complexity worsens
Solution Approach 1:
Combustion additives (such as calcium compounds, magnesium compounds, or silicon compounds) are introduced as intermediary substances that mediate between the biomass combustion products and the heat transfer surfaces. These additives form protective layers or modify flue gas chemistry to reduce corrosion, while the fuel preparation system is designed to incorporate these additives in a manageable way
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 steam explosion process makes biomass easier to grind and reduces the energy required for grinding, while additives minimize fouling and corrosion, enhancing heat transfer efficiency and extending equipment lifespan.
Implementation Method 1
steam explosion treatment of biomass followed by the addition of suitable combustion additives to the biomass-based fuel, which simplifies grinding
Implementation Method 2
additives minimize fouling and corrosion, enhancing heat transfer efficiency and extending equipment lifespan
Data Source
Figure 1a~1b
Figure 1c~2
Figure 3a
AI summary
Biomass based fuel configured to reduce chemical and/or mechanical effects of flue gas on heat transfer surfaces. The biomass based fuel comprises steam-exploded biomass and some combustion additive. The combustion additive is selected from a group of additives that are capable of reducing chemical and/or mechanical effects of flue gas on heat transfer surfaces. The combustion additive may comprise fouling-reducing additive and/or an additive reducing corrosion potential. In addition, a method for manufacturing biomass based fuel configured to reduce chemical and/or mechanical effects of flue gas on heat transfer surfaces. The method comprises providing biomass and steam into a reactor; maintaining said biomass and said steam simultaneously in the reactor, in a pressure of at least 10 bar(a) and at a temperature from 180 °C to 250 °C for at least 2 minutes; and decreasing the pressure in the reactor and/or conveying biomass out of the reactor such that the pressure of the environment of the biomass decreases below 5 bar(a), to produce steam- exploded biomass. The method further comprises adding some combustion additive to the biomass and/or the steam-exploded biomass.