Powder Fuel Burner With Center Flow Blocker for Coke Ignition
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Solution Overview
Problem
Conventional burners are not suitable for directly combusting flame-retardant fuels like petroleum coke due to inappropriate air-fuel ratios, and adopting indirect combustion systems increases equipment costs.
Innovation Solution
A powder fuel burner design with a cylindrical air-fuel mixture conveying tube, swirl vane, and center flow blocker that adjusts the air-fuel ratio locally to improve ignitibility of flame-retardant fuels by reducing the air-fuel mixture's effective ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an indirect combustion system is adopted to achieve suitable air-fuel ratio for flame-retardant powder fuel, then ignitibility is improved, but equipment cost increases due to additional solid-gas separator and storage tank
Solution Approach 1:
The invention changes the air-fuel ratio parameter by introducing a secondary air supply system that injects additional air into the combustion chamber. This allows the burner to achieve the lower air-fuel ratio needed for flame-retardant fuels like petroleum coke without requiring solid-gas separation or storage tanks, thus improving ignitibility while avoiding increased equipment complexity
Solution Approach 2:
The invention segments the air supply into two distinct paths: conveying air that transports the powder fuel from the pulverizer, and secondary air that is independently supplied through the air-fuel mixture supply passage. This segmentation allows precise control of the air-fuel ratio by regulating secondary air flow, achieving suitable combustion conditions for flame-retardant fuels without additional equipment
2Device complexity
If conventional air-fuel mixture is used for pulverized coal, then equipment simplicity is maintained, but ignitibility is insufficient for flame-retardant powder fuel
Solution Approach 1:
The invention performs preliminary action by pre-mixing the powder fuel with secondary air in the air-fuel mixture supply passage before injection into the combustion chamber. This preliminary mixing ensures that the air-fuel ratio is optimized for flame-retardant fuels before combustion begins, improving ignitibility while maintaining equipment simplicity through direct injection
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 design allows for stable combustion of flame-retardant fuels like petroleum coke with improved ignitibility and reduced NOx generation, without the need for additional equipment.
Implementation Method 1
a swirl vane mounted at the distal end of the air-fuel mixture conveying tube
Implementation Method 2
a rod-shaped center flow blocker mounted on a center axis of the air-fuel mixture conveying tube at a position upstream of the swirl vane in a conveying direction of the air-fuel mixture
Implementation Method 3
a cylindrical air-fuel mixture conveying tube, through which an air-fuel mixture is conveyed and which injects, from a distal end thereof, the air-fuel mixture into the combustion chamber
Data Source
AI summary
A powder fuel burner mounted in a combustion chamber of a boiler includes: a cylindrical air-fuel mixture conveying tube, through which an air-fuel mixture is conveyed and which injects, from a distal end thereof, the air-fuel mixture into the combustion chamber, the air-fuel mixture being a mixture of a powder fuel and conveying air; a swirl vane mounted at the distal end of the air-fuel mixture conveying tube; and a rod-shaped center flow blocker mounted on a center axis of the air-fuel mixture conveying tube at a position upstream of the swirl vane in a conveying direction of the air-fuel mixture, the center flow blocker including a cylindrical surface that is concentric with the air-fuel mixture conveying tube and that extends in a direction of the center axis.