Modular Heat Recovery Steam Generator Installation
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Solution Overview
Problem
Modular heat recovery steam generator construction faces a trade-off between on-field installation cost and shipping cost, with high pre-fabrication leading to high shipping costs and low pre-fabrication resulting in high on-field installation costs, posing safety hazards and inefficiencies during installation and transportation.
Innovation Solution
A method involving pre-assembling HRSG modules with the open side facing downward and side casing upward, allowing exterior structural steel attachment in a horizontal position without lifting, reducing installation and transportation costs and improving safety by lowering the center of gravity and eliminating the need for elevated work.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a high degree of pre-fabrication is provided to reduce on-field installation cost, then on-field installation cost is reduced, but shipping cost increases
Solution Approach 1:
The module is pre-assembled with the functional unit housed in the casing structure before transportation, allowing preparation work to be done in advance at a controlled environment rather than at the installation site. This resolves the contradiction by enabling sufficient pre-fabrication to reduce on-field installation cost while maintaining a manageable degree that controls shipping cost.
Solution Approach 2:
The HRSG is divided into modular units that can be pre-assembled to a specific degree and then transported. This segmentation allows optimization of the pre-fabrication level - not too minimal to keep shipping cost high, not too extensive to make shipping cost prohibitive - thereby resolving the cost trade-off.
2Ease of manufacture
If the module is arranged with open side facing upward for traditional installation, then structural steel attachment is simplified, but safety hazards increase due to elevated work requirements
Solution Approach 1:
Instead of the traditional approach where the open side faces upward during installation, this invention inverts the orientation so the open side faces downward. This inversion allows structural steel to be attached at ground level rather than requiring workers to perform elevated work, thereby eliminating safety hazards while maintaining attachment feasibility.
Solution Approach 2:
By orienting the module with the open side facing downward, the attachment work is performed at ground level (equipotential with worker position) rather than at elevated positions, eliminating the need for workers to work at heights and thus removing the associated safety hazards.
3Stability of the object's composition
If the module is lifted to vertical position before attaching structural steel, then proper alignment is achieved, but installation time and cost increase
Solution Approach 1:
The module is attached to the structural steel in a horizontal position before being lifted to the vertical position. This preliminary attachment at ground level allows for easier alignment and connection work, saving time compared to lifting the heavy module first and then attempting alignment at elevated position.
Solution Approach 2:
Instead of the conventional sequence of lifting first then attaching, this invention inverts the sequence by attaching in horizontal position first and then lifting to vertical position. This inversion reduces installation time by performing attachment work at ground level where access and maneuverability are superior.
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 reduces installation and transportation costs, enhances safety, and achieves a balance between pre-fabrication and shipping costs, with potential savings of $600,000-$800,000 in total installed cost for combined cycle installations.
Implementation Method 1
The heat exchanger tubes carry a medium comprising water and/or steam to which heat from the exhaust gas is transferred, to produce steam at high temperature and pressure
Implementation Method 2
A heat recovery steam generator or HRSG is an energy recovery heat exchanger that recovers heat from a hot gas stream
Data Source
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AI summary
A method for installing a heat recovery steam generator (1) with a plurality of preassembled modules (10) includes arranging a pre-assembled module (10) at an installation site. The pre-assembled module (10) includes a functional unit of the heat recovery steam generator (1) housed in a casing structure (12). The casing structure (12) includes a top casing (12a), a bottom casing (12b) and a side casing (12c). An open side (15) is defined opposite to the side casing (12c). The module (10) is arranged horizontally at the installation site with the open side (15) facing downward and the side casing (12c) facing upward. The method includes attaching a structural steel (13) to the side casing (12c) in a horizontal position without lifting the module (10). The module (10) with the attached structural steel (13) is lifted to a vertical position and secured to a foundation (60). Also described is a method for pre-assembling the module (10) and a method for transporting the pre-assembled module (10) to the installation site.