Drying Gas Temperature Control in IGCC Carbonaceous Feedstock
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In IGCC systems, the limited upper temperature of the drying gas restricts the drying efficiency of carbonaceous feedstocks with high moisture content, leading to potential dew condensation and agglomeration issues during coal transportation and reduced gasification efficiency, limiting the types of fuels that can be used.
Innovation Solution
A carbonaceous feedstock gasification power generation facility that includes a system for bleeding high-temperature and low-temperature flue gases from a heat recovery steam generator and adjusting their mixture to achieve a higher drying gas temperature, using an extreme high-temperature flue gas line to increase the drying gas temperature further, along with temperature adjustment means and NOx concentration control to optimize drying efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drying gas temperature is increased to improve drying efficiency of high-moisture carbonaceous feedstocks, then the drying efficiency improves, but the NOx concentration in the discharged flue gas increases beyond regulation values
Solution Approach 1:
The flue gas flow is segmented into multiple paths: a first flue gas line that bypasses the denitration device for high-temperature drying, and a second flue gas line that passes through the denitration device for low-NOx discharge. This segmentation allows the system to use high-temperature flue gas for drying while treating a separate portion for emission control, resolving the contradiction between drying efficiency and NOx concentration.
Solution Approach 2:
The patent introduces an intermediate high-temperature flue gas line that serves as a mediator between the high-temperature source and the drying process. This intermediate pathway allows selective extraction of high-temperature flue gas for drying purposes without subjecting the entire flue gas flow to high temperatures, thereby enabling efficient drying while maintaining NOx control through the denitration device for the main discharge flow.
2Object-generated harmful factors
If the drying gas temperature is limited to maintain denitration efficiency, then the NOx concentration is controlled, but the drying efficiency of high-moisture feedstocks becomes insufficient
Solution Approach 1:
The system segments the flue gas utilization into two functional streams: one stream (first flue gas line) is dedicated to providing high temperature for drying with bypass of the denitration device, while another stream (second flue gas line) passes through the denitration device to ensure NOx control for discharge. This segmentation allows each stream to optimize for its specific function, resolving the contradiction between temperature requirements for drying and temperature constraints for denitration efficiency.
Solution Approach 2:
Different portions of the flue gas are assigned different temperature qualities based on their destination: high-temperature quality is directed to the drying process where it is needed, while the main discharge flow maintains lower temperature quality suitable for denitration and emission control. This local differentiation of thermal quality allows simultaneous optimization of both drying efficiency and NOx control.
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 allows for sufficient drying of carbonaceous feedstocks with high moisture content, expanding the range of usable fuels and improving gasification efficiency by increasing the drying gas temperature beyond the conventional limits, thus preventing transportation issues and enhancing power generation capabilities.
Implementation Method 1
an upstream-side heat exchange portion (92) made up of one or more heat exchangers
Implementation Method 2
a downstream-side heat exchange portion (94) made up of one or more heat exchangers
Implementation Method 3
an in-furnace denitration device (93)... setting the NOx concentration of the drying gas being discharged to the atmosphere to a regulation value or less
Implementation Method 4
a high-temperature flue gas line (31H) that bleeds a high-temperature flue gas from the furnace... and supplies the high-temperature flue gas to the pulverizing device (1) as a drying gas
Implementation Method 5
a low-temperature flue gas line (31L) that bleeds a low-temperature flue gas from the furnace... and supplies the low-temperature flue gas to the high-temperature flue gas line (31H) or directly to the pulverizing device (1)
Data Source
AI summary
A carbonaceous feedstock gasification power generation facility, and a method for regulating a gas for drying gas this carbonaceous feedstock, are disclosed with which it is possible to expand the range of the types of carbonaceous feedstocks that can be used. High-temperature exhaust gas, low-temperature exhaust gas and extreme high-temperature exhaust gas are bled from the furnace respectively at a high-temperature bleed position, a low-temperature bleed position and an extreme high-temperature bleed position. When these exhaust gases are mixed, the flow volume of the extreme high-temperature exhaust gas supplied to at least one of the exhaust gases, that is, the high-temperature exhaust gas or the low-temperature exhaust gas, is adjusted such that the temperature of at least one of these exhaust gases, that is, the high-temperature exhaust gas or the low-temperature exhaust gas, reaches a prescribed temperature.