Common Tunnel HRSG Layout for Coke Oven Exhaust Gas Sharing
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Solution Overview
Problem
Conventional coke-making facilities face challenges in minimizing the loss of volatile gases and hazardous pollutants due to small cracks and openings in refractory structures, particularly in Horizontal Heat Recovery (HHR) ovens operating under negative pressure, which can lead to the venting of hot exhaust gases to the atmosphere during offline HRSG conditions.
Innovation Solution
The implementation of a gas-sharing system that redirects hot exhaust gases from an offline HRSG to online HRSGs through an expanded common tunnel with increased draft and parallel HRSG configurations, eliminating the need for bypass exhaust stacks and enhancing energy recovery by maintaining negative pressure within the coke plant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If HHR ovens operate under negative pressure to draw in air for combustion, then heat recovery efficiency is improved, but volatile gases and hazardous pollutants can leak into the atmosphere through cracks and openings
Solution Approach 1:
The patent converts the harmful effect of negative pressure (which causes pollutant leakage through cracks) into a beneficial feature by designing the system so that the same negative pressure draws in air for combustion and prevents volatile gas escape. The negative pressure becomes advantageous when properly managed through the gas-sharing system and parallel HRSG configuration, turning a potential harm into the mechanism for efficient combustion and heat recovery.
Solution Approach 2:
The patent changes the operational parameters by implementing parallel HRSG configurations and gas-sharing systems that allow flexible control of pressure conditions. This enables the system to maintain optimal negative pressure for heat recovery while preventing pollutant leakage through coordinated operation of multiple HRSGs and controlled air intake.
2Reliability
If an HRSG goes offline for maintenance or operation, then individual HRSG reliability is improved, but hot exhaust gases are vented to the atmosphere causing energy loss
Solution Approach 1:
The patent merges multiple HRSGs into a parallel configuration with a common tunnel system, allowing exhaust gases from online HRSGs to be shared and redistributed to other online HRSGs when one goes offline. This combining of resources ensures continuous energy recovery without venting to atmosphere, maintaining system reliability while preventing energy loss.
Solution Approach 2:
The patent creates a universal gas-sharing system where the common tunnel and parallel HRSG configuration allow any online HRSG to receive and process exhaust gases from any other online HRSG. This multi-functional arrangement ensures that the system can maintain full energy recovery capability regardless of which specific HRSG is offline, making the system adaptable and resilient.
3Temperature
If refractory structures are used in HHR ovens, then high temperature resistance is improved, but small cracks and openings form during operation allowing gas leakage
Solution Approach 1:
The patent accepts that refractory structures will develop cracks under high temperature operation but converts this potential harm into a benefit by designing the negative pressure system to draw air through these cracks for combustion rather than allowing volatile gases to escape. The cracks become unintended air intake points that support the combustion process.
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 prevents the discharge of hot exhaust gases to the atmosphere, increases the efficiency of the cogeneration plant, and allows for the operation of more ovens per HRSG, thereby optimizing energy utilization and reducing environmental impact.
Implementation Method 1
expanded common tunnel with increased draft
Implementation Method 2
maintaining negative pressure within the coke plant
Data Source
AI summary
A coke plant includes multiple coke ovens where each coke oven is adapted to produce exhaust gases, a common tunnel fluidly connected to the plurality of coke ovens and configured to receive the exhaust gases from each of the coke ovens, multiple standard heat recovery steam generators fluidly connected to the common tunnel where the ratio of coke ovens to standard heat recovery steam generators is at least 20:1, and a redundant heat recovery steam generator fluidly connected to the common tunnel where any one of the plurality of standard heat recovery steam generators and the redundant heat recovery steam generator is adapted to receive the exhaust gases from the plurality of ovens and extract heat from the exhaust gases and where the standard heat recovery steam generators and the redundant heat recovery steam generator are all connected in parallel with each other.