Automatic Draft Control for Coke Oven Heat Recovery
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Solution Overview
Problem
Conventional coke plants face challenges in minimizing the loss of volatile gases and maintaining optimal operating conditions, particularly in Horizontal Heat Recovery (HHR) ovens, where negative pressure environments can lead to air leaks and inefficient heat recovery due to small cracks and openings, resulting in reduced efficiency and environmental pollution.
Innovation Solution
The implementation of an automatic draft control system that includes sensors to detect operating conditions such as oven draft, temperature, and oxygen concentration, and an actuator to adjust the uptake damper, ensuring targeted oven drafts and temperature ranges are maintained, while also redirecting exhaust gases through a network of heat recovery steam generators to prevent venting to the atmosphere during offline HRSG situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If HHR ovens operate under negative pressure to draw in air for combustion, then heat recovery efficiency is improved, but air leaks through cracks increase causing loss of volatile gases
Solution Approach 1:
The patent applies dynamics by making the damper positions adjustable and controllable rather than fixed. The uptake damper and primary air damper positions can be dynamically changed based on operating conditions to optimize the balance between maintaining negative pressure for heat recovery and minimizing air leaks through cracks.
Solution Approach 2:
The patent changes operational parameters (damper positions, pressure differentials) to resolve the contradiction. By adjusting the uptake damper and primary air damper positions, the system can modify the degree of negative pressure and air flow through cracks, thereby controlling the trade-off between heat recovery efficiency and volatile gas loss.
2Loss of substance
If uptake damper is closed to reduce air leaks, then volatile gases are retained, but oven draft decreases reducing combustion efficiency
Solution Approach 1:
The patent segments the air control function into two independent dampers: the uptake damper that controls overall exhaust flow and oven draft, and the primary air damper that controls air intake for combustion. This segmentation allows independent optimization of each function - the uptake damper can be adjusted to retain volatile gases while the primary air damper ensures sufficient oxygen supply for combustion efficiency.
Solution Approach 2:
The primary air damper acts as an intermediary element that mediates between the conflicting requirements of volatile gas retention and combustion efficiency. By controlling primary air intake separately from exhaust flow, it enables the system to maintain negative pressure for gas retention while still providing adequate oxygen for combustion through the sole flue.
3Device complexity
If manual control of dampers is used, then system complexity is reduced, but ability to maintain optimal operating conditions deteriorates
Solution Approach 1:
The patent implements feedback control by using sensors to detect operating conditions (oven pressure, temperature, air flow) and automatically adjusting damper positions to maintain optimal parameters. This feedback mechanism ensures stable operating conditions without requiring complex manual intervention, as the system self-regulates based on real-time measurements.
Solution Approach 2:
The control system performs self-service by automatically monitoring and adjusting damper positions based on sensor inputs. The system manages its own operation without external intervention, maintaining optimal combustion conditions and volatile gas retention through automated feedback loops, thereby reducing the need for complex manual control while improving reliability.
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 solution enhances the efficiency of coke production by maintaining optimal operating conditions, reducing air leaks, and preventing the venting of untreated exhaust gases, thereby improving energy recovery and environmental sustainability.
Implementation Method 1
a draft sensor configured to detect the oven draft
Implementation Method 2
a temperature sensor configured to detect an uptake duct temperature
Implementation Method 3
an oxygen sensor configured to detect an uptake duct oxygen concentration in the uptake duct
Implementation Method 4
fluidly connecting multiple heat recovery steam generators to the common tunnel
Implementation Method 5
Hot exhaust gases generated by the coke making process
Data Source
AI summary
A coke oven includes an oven chamber, an uptake duct in fluid communication with the oven chamber, the uptake duct being configured to receive exhaust gases from the oven chamber, an uptake damper in fluid communication with the uptake duct, the uptake damper being positioned at any one of multiple positions, the uptake damper configured to control an oven draft, an actuator configured to alter the position of the uptake damper between the positions in response to a position instruction, a sensor configured to detect an operating condition of the coke oven, wherein the sensor includes one of a draft sensor, a temperature sensor configured to detect an uptake duct temperature or a sole flue temperature, and an oxygen sensor, and a controller being configured to provide the position instruction to the actuator in response to the operating condition detected by the sensor.