Water-Cooled Grate Block Layout for Uniform Hotspot Cooling
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Solution Overview
Problem
Existing combustion grates for waste incineration suffer from high thermal stress and wear due to uneven material distribution, leading to reduced service life and inefficient cooling performance, particularly at 'heat hotspots' where coolant contact is limited.
Innovation Solution
A grate block design featuring a planar cavity with a distribution element to evenly distribute cooling fluid across the cavity, preventing turbulence and air inclusion, and a partition to ensure uniform cooling, enhancing cooling capacity and reducing thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling channels or cooling lines are used to cool the grate blocks, then the cooling capacity is improved in certain areas, but the cooling coverage is insufficient leading to heat hotspots on the combustion surface
Solution Approach 1:
The cooling system is segmented into multiple independent cooling lines arranged in rows, with each cooling line serving a specific region of the grate block. This segmentation allows for distributed cooling coverage across the entire combustion surface, eliminating the heat hotspots that occur with centralized cooling channels.
Solution Approach 2:
Different regions of the grate block are provided with localized cooling lines positioned directly beneath high-thermal-stress areas. The cooling lines are strategically placed to match the thermal load distribution, ensuring that each local region receives appropriate cooling coverage proportional to its thermal demands.
2Use of energy by moving object
If deflectors are used to form meandering water channels, then the cooling path is extended, but the cooling performance is impaired directly above the deflectors where coolant has no contact with the upper wall
Solution Approach 1:
The deflectors that created dead zones in previous designs are removed. Instead, straight cooling lines are installed that extend fully beneath the combustion surface, ensuring continuous coolant contact with the upper wall across the entire grate block width and length, eliminating heat hotspots.
Solution Approach 2:
The cooling system transitions from a meandering two-dimensional path with deflectors to a multi-row arrangement of parallel cooling lines. This dimensional reorganization ensures comprehensive coverage beneath the combustion surface without creating dead zones, maintaining constant coolant contact with the upper wall.
3Area of stationary object
If cooling lines run perpendicular to the feed direction and are deflected outside the grate blocks, then the cooling lines are positioned for heat exchange, but turbulence and bubble formation occur reducing cooling capacity
Solution Approach 1:
Flow straightening elements are installed at the inlet of each cooling line to pre-condition the coolant flow before it enters the heat exchange region. These elements eliminate turbulence and bubble formation upstream, ensuring laminar, stable flow throughout the cooling line and maximizing heat exchange efficiency.
Solution Approach 2:
Flow straightening elements act as intermediaries between the coolant supply and the cooling lines. These elements mediate the flow transition, converting turbulent inlet flow into smooth, laminar flow that maintains stable contact with the grate block underside, preventing bubble formation and ensuring reliable cooling.
4Reliability
If the coolant flow is not consistent, then turbulence and bubble formation occur in the cooling lines, but maintaining consistent flow reduces cooling capacity through improper distribution
Solution Approach 1:
Flow straightening elements are positioned at the inlet of each cooling line to pre-condition the coolant before it enters the heat exchange region. This preliminary action ensures laminar flow establishment and consistent distribution throughout the cooling system, preventing both turbulence and improper flow patterns.
Solution Approach 2:
The cooling system is divided into multiple independent cooling lines, each with its own flow straightening element and inlet. This segmentation allows each line to maintain independent, consistent flow patterns, ensuring uniform coolant distribution across all regions of the grate block without interference from turbulence in adjacent lines.
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 improved cooling performance reduces thermal stress and wear on the grate blocks, minimizing maintenance and increasing the operational efficiency and longevity of the combustion plant.
Implementation Method 1
the grate bars are normally cooled from below, i.e., on the side of the combustion grate opposite the combustion process, using a coolant or cooling fluid
Implementation Method 2
Water or air is typically used as the coolant, as a result of which the grate blocks are referred to as air-cooled or water-cooled
Data Source
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AI summary
A cooled grate block (1) as part of a grate for a plant for the thermal treatment of waste, comprising: a block body (3) designed as a casting with an outer support surface (7) for the waste to be treated, a planar cavity (50) arranged directly below the support surface (7) for receiving a cooling fluid, a fluid supply line (52) and a fluid discharge line (54) which are connected to the cavity (50), at least one deflection element (66) arranged in the cavity (50) to direct a cooling fluid in the cavity (50) from the fluid supply line (52) to the fluid discharge line (54), and a distribution element (74) arranged in the end face (11) of the cavity (50) for distributing the cooling fluid fed into the cavity (50) through the fluid supply line (52), characterized in that the planar cavity (50) has a surface extending from the bottom (51) to upper wall (5) has a partition wall (60) extending to the upper wall,which extends from the front wall (15) towards the rear wall (68) of the cavity (50), forms a passage (64) in the area of the rear wall (68) and divides the cavity (50) into two fluid-conducting compartments (62).