MEASUREMENT & TESTING Permanent process control in cement kilns
Permanent and uninterrupted process control in cement rotary kilns is required to increase clinker quality and output, reduce harmful emissions and to decrease maintenance costs of plant infrastructure / prevent plant downtime.
This can be achieved with the CEMTEC kiln probe system produced by ENOTEC in Germany. CEMTEC is self-monitoring and self-cleaning which enables uninterrupted flue gas analysis.
The difficulty of the sample gas extraction from cement kilns has long been a common problem for Control & Instrumentation departments and cement plant operators.
The measuring point at the kiln inlet chamber is notoriously difficult because of the challenging conditions of high and sticky dust loading (blocking of probes), corrosive flue gas (corrosion and blocking of heated gas extraction lines) and heterogeneous fuel (increased RDF).
Additionally the trend of increased use of RDF (Refuse Derived Fuel) causes combustion related challenges as the secondary fuel feed rate needs to be optimally controlled by the measurement data. Combustion control:
Main combustion parameters, O2 , NOx permanent measurements enable reduction of CO2
and CO, need to be monitored and tightly controlled, which among other things enables the production of permanently high clinker quality. Importantly these emissions and help keep NOx
emissions below abatement limits. Additionally NH3
denitrification spraying system - the relationship between NOx Keeping excess O2
Low excess O2 automatically results in low NOx Low excess CO results in reduced CO2 Low O2
slip can be reduced because of increased efficiency of the SNCR in the kiln inlet chamber and ammonia water consumption of the SNCR system are directly connected.
and CO low after combustion from the kiln main burner is the most important objective from a process control point of view: production / emissions and a lowered requirement of ammonia input for NOx
and low CO after combustion is thus an indicator of finely-tuned main burner combustion. On the other hand, high excess O2
controlling a combustion process which can only be guaranteed by permanent process control.
Prevention of plugging: Simple measures also have a large impact: By limiting the dust intake into the kiln sample probe, the automatic requirement for purging is decreased. During the purging process, no process measurements are possible so the availability of measured values decreases. Sticky dust deposits within the sample probe often need to be cleaned manually by maintenance staff. This is difficult and dangerous work.
Plugging of the probe entrance is typical for probes without a plunger system which necessitates manual cleaning in short intervals. Limiting dust ingress in addition to an effective filter system is key to delivering dust free sample gas to downstream analyzers.
Prevention of sticking:
Due to the probe being inserted into the kiln for prolonged periods, most probes on the market are prone to getting stuck in the process due to being “cemented in” at the duct flange where the cement mix / raw meal is stationary and due to being pre-calcined, will start to harden. A stuck probe is prone to bending at some stage and will need to be pulled out with a pulley system if the retraction motors don’t have sufficient torque or if other mitigation properties aren’t available.
Solution:
In over 100 installations worldwide, the German designed and built CEMTEC probe system continues to impress through its ability to self-clean and self-monitor to the extent of being fully autonomous 24/7 and deliver dust-free sample gas to downstream analyzers for permanent process control and monitoring.
The internal probe plunger removes deposits from the probe entrance in regular intervals to ensure continuous gas extraction.
The probe rotation motor rotates the probe +/- 45 ° in regular intervals to prevent sticking and bending.
The low dust ingress construction and large surface area internal filter ensures a continuous flow of dust free sample gas.
All powerful motors are pneumatically driven and are as such independent of the plant’s power supply.
The CEMTEC probe system requires only one maintenance cycle per year which coincides well with the plant planned maintenance for repairs to e.g the refractory lining. This ensures highest possible efficiency.
Additionally, because of the effect of the CEMTEC to decrease plant wear & tear, the operation time between plant shutdowns can be increased which results in increased clinker output.
More information omline:
ilmt.co/PL/qxMj For More Info, email:
www.enotec.com
56760pr@reply-direct.com
email: For More Info, email:
sean.turner@enotec.com @ENOTEC CEMTEC®
Gas sampling probe system for cement kilns
Continuous gas measurement in cement kilns Self-cleaning and self-monitoring probe system 95% availability of process values Increased fuel efficiency / reduced emissions High SNCR efficiency, reduced ammonia slip Reduced destruction of refractory lining
reduction. Additionally this is an indicator of fuel efficiency. emissions and is less damaging to plant infrastructure, such as to the refractory lining, causing less downtime of the plant for repairs. after combustion is wasteful and higher CO concentrations are usually the result of an oxygen deficient combustion (lambda < 1). This is the importance of precisely
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ANNUAL BUYERS’ GUIDE 2022
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