Angled Injection Lance for Cement Kiln NOx Reduction
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Solution Overview
Problem
Conventional lance systems for injecting reagents into combustion gases in cement works and other industrial processes face challenges such as rapid caking due to high dust loads, leading to reduced effectiveness and increased maintenance costs, as well as inefficiencies in reaching the central areas of large reaction chambers.
Innovation Solution
A lance system with a cladding tube and injection lance where the nozzle is angled relative to the cladding tube, allowing for a gap that reduces caking and enables better coverage of the reaction chamber, utilizing two concentric enveloping air curtains to protect the nozzle and ensure effective reagent distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lance systems are used in high dust load environments, then reagent injection is achieved, but rapid caking occurs leading to reduced effectiveness and increased maintenance
Solution Approach 1:
The lance system is divided into two separable parts: a cladding tube that remains in the reaction chamber and an injection lance that can be removed for maintenance. This segmentation allows the injection lance to be easily replaced when caked, while the cladding tube remains in place, significantly reducing maintenance time and improving reliability.
Solution Approach 2:
A gap is introduced between the injection lance and cladding tube, filled with enveloping air that acts as a protective intermediary layer. This air curtain prevents direct contact between dust-laden flue gases and the nozzle, reducing caking on the injection lance while maintaining effective reagent delivery.
2Ease of operation
If wall nozzles are used in large reaction chambers, then installation is simple, but central areas cannot be reached effectively
Solution Approach 1:
The injection lance is designed to be movable and adjustable within the cladding tube, allowing it to be positioned at different angles and locations. This dynamic positioning capability enables the system to reach central areas of large reaction chambers while maintaining ease of installation through the removable lance design.
Solution Approach 2:
The system transitions from fixed wall-mounted nozzles to an adjustable internal lance configuration. The injection lance can be oriented at various angles (0-90 degrees relative to the cladding tube axis), adding dimensional flexibility that enables coverage of central reaction chamber areas that wall nozzles cannot reach.
3Productivity
If long lances are used to reach central areas, then coverage improves, but maintenance becomes more difficult and time-consuming
Solution Approach 1:
The lance system is segmented into a long cladding tube that remains in the reaction chamber and a removable injection lance. This allows the injection lance to be easily pulled out for maintenance regardless of its length, solving the problem that long lances would be difficult to maintain if they were fixed structures.
Solution Approach 2:
The injection lance is extracted as a separate removable component from the cladding tube. This extraction allows the injection lance to be completely removed from the reaction chamber for cleaning and maintenance, while the cladding tube remains in place, significantly reducing maintenance difficulty and time even for long lance configurations.
4Productivity
If reagent is injected directly into flue gas, then pollutant reduction is achieved, but reagent is wasted due to rapid mixing and insufficient reaction time
Solution Approach 1:
The reagent is pre-mixed with air in the injection lance before exiting into the flue gas. This preliminary mixing creates a controlled air-reagent mixture that enhances atomization and extends the reaction time in the reaction chamber, preventing rapid mixing with flue gas and reducing reagent waste while improving pollutant reduction efficiency.
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 lance system allows for longer maintenance intervals, improved reagent distribution, and reduced caking, enabling more efficient pollutant reduction with lower reagent usage and compliance with stricter NOx emission limits.
Implementation Method 1
The nozzle (8) of the injection lance (7) is aligned in relation to the internal opening of the end plate (9) so that the nozzle (8) can inject the reagent through the internal opening of the end plate (9)
Implementation Method 2
the cladding tube has an end plate at its distal end, which delimits the interior of the cladding tube to the outside
Implementation Method 3
utilizing two concentric enveloping air curtains to protect the nozzle and ensure effective reagent distribution
Implementation Method 4
Methods and devices of the aforementioned type are already known. The reactants are, for example, ammonia and/or urea, which can reduce the proportion of nitrogen oxides in the flue gas
Implementation Method 5
Thermal NO x essentially occurs at temperatures greater than about 1,200°C to 1,500°C, because it is only at these temperatures that the molecular oxygen present in the air noticeably changes into atomic oxygen (thermal oxidation)
Data Source
Figure 1
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Figure 3~4
AI summary
The invention relates to a lance system (1) for introducing reagents by means of a nozzle (8) into reaction chambers (2) through which combustion gases (3) flow, wherein the lance system (1) comprises: - a sheath tube (6) configured to be arranged at least partially within the reaction chamber (2); - an injection lance with a feed tube for a liquid reagent, optionallya supply tube for compressed air, and with the nozzle for injecting the reagent, wherein the injection lance can be inserted into the casing tube; characterized in that the casing tube (6) has a closing plate (9) at its distal end, which limits the interior of the casing tube (6) to the outside, wherein the closing plate (9) has an internal opening (11) for arranging the nozzle (8) and the plane of the closing plate (9) of the casing tube (6) is arranged at an angle of 25 to 65° to the longitudinal axis of the casing tube, the longitudinal axis of the nozzle (8) of the injection lance (7) in the installed state is angled at an angle of 25 to 65° to the longitudinal axis of the casing tube (6) and is inclined towards the closing plate (9); and the nozzle (8) of the injection lance (7) is arranged and aligned in relation to the inner opening of the end plate (9) so that the nozzle (8) can inject the reagent through the inner opening (11) of the end plate (9).The invention further relates to a reaction chamber (2) designed to be permeated by combustion gases, wherein the reaction chamber (2) contains at least one lance system (1) according to the invention; and a method for injecting reagents in the form of fluids into combustion gases (3) within a reaction chamber (2) permeated by these combustion gases (3), wherein the reagents are injected into combustion gases (3) permeating the reaction chamber (2) by means of at least one lance system (1) according to the invention.