Pulverized Coal Injection for Mercury Capture in Cement Preheaters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cement plants are significant sources of mercury emissions, and existing methods for reducing these emissions are costly and require extensive reconfiguration, necessitating a cost-effective and easily implementable solution.
Innovation Solution
Injecting pulverized coal into preheater cyclones of cement plants, where it undergoes steam activation and is enhanced with bromine-containing substances to absorb mercury, which is then collected with other particulates, allowing for recirculation and repeated mercury capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If activated carbon is injected into the gas stream to capture mercury, then mercury emissions are reduced, but the cost and complexity of the system increases
Solution Approach 1:
The invention extracts the mercury capture function from a separate activated carbon injection system and integrates it into the existing preheater cyclones. By removing the need for separate carbon injection equipment and utilizing the existing cyclone structure, the system reduces complexity while maintaining mercury removal capability.
Solution Approach 2:
The preheater cyclones, which already serve the function of separating particulates from the gas stream, are given an additional function by injecting pulverized coal into them. This multi-functional approach allows the same equipment to handle both particulate separation and mercury capture without requiring separate dedicated systems.
2Object-generated harmful factors
If activated carbon is injected into the gas stream to capture mercury, then mercury emissions are reduced, but the cost of implementation increases
Solution Approach 1:
The invention uses pulverized coal, which is a cheap and readily available material, as the mercury capture medium instead of expensive activated carbon. The coal is injected into the preheater cyclones, undergoes steam activation in situ, and is then removed with the waste coal from the preheater system, providing a cost-effective solution.
Solution Approach 2:
The system uses the steam already present in the preheater tower to activate the pulverized coal for mercury capture. The existing steam serves a dual purpose: preheating the incoming raw materials and activating the coal particles for mercury adsorption, eliminating the need for separate activation equipment or additional energy input.
3Ease of manufacture
If pulverized coal is injected into preheater cyclones for mercury capture, then emission reduction cost is lowered, but the effectiveness of mercury capture must be maintained
Solution Approach 1:
The invention changes the physical and chemical parameters of the pulverized coal by subjecting it to steam activation in the high-temperature environment of the preheater cyclones. This transformation converts the coal into an activated state with high mercury adsorption capacity, ensuring effective mercury capture despite using a cheaper material like coal instead of activated carbon.
Solution Approach 2:
The system creates a composite material by combining pulverized coal with steam activation in the preheater cyclones. The coal particles undergo chemical and physical changes during activation, forming a composite structure that enhances their mercury capture capability while maintaining the cost advantages of using coal as the base material.
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 method effectively reduces mercury emissions at a low cost, achieving significant emission reductions without requiring extensive modifications to existing cement plant infrastructure.
Implementation Method 1
where it undergoes steam activation and is enhanced with bromine-containing substances to absorb mercury
Implementation Method 2
the mercury is captured and held by the activated carbon particles
Implementation Method 3
The particles are then collected by a particulate collection device, such as an electrostatic precipitator or a baghouse filter
Data Source
AI summary
This invention provides a method for reducing mercury emissions from a cement plant comprising at least a particulate collection device and a preheater tower comprised of one or more preheater cyclones. The method comprises injecting pulverized coal into at least one preheater cyclone of said cement plant.