An economic cement production strongly depends on energy efficiency in production processes and on securing a high product quality. Hereby, the co‑incineration of alternative fuels in substituting primary fuels is gaining more importance. Therefore it is necessary to continuously monitor the processes with analyzing systems, also in order to comply with the relevant emission limit values.
SICK analyzing systems are highly qualified for cement applications. With its wide range of products SICK is able to provide the optimal solution for all relevant parameters, even at high temperature and / or high dust conditions. SICK, is the only manufacturer with own solutions for dust, gas flow, pollutants, reference gases, and data evaluation systems.
Pulverized coal is a common fuel in a cement plant. Due to safety reasons, monitoring of CO concentration in coal bunkers and coal mills is an essential issue. Increasing CO concentrations may indicate a smouldering fire and require immediate counter measures. In addition, O2 concentrations provide significant information for coal mills which are operated under inert gas purging: By monitoring the oxygen concentration during the grinding process the entrance of false air into the system can be detected at an early stage. Herewith the danger of explosion or fire can be minimized. Our solution:
MKAS Compact analyzing system
The raw material enters the kiln via pre-heater and pre-calciner. ln the kiln, the sintering process takes place at temperatures up to 1.400 °C. The final product, clinker is leaving the kiln at the opposite end for further processing. Producing high quality clinker is requiring accurate control of energy input: Insufficient heat will leave unconverted lime while excess heat increases fuel consumption and could damage the kiln. Energy input and optimal combustion conditions can be derived from gas analysis data taken from the process gas at kiln inlet. Application task is to continuously monitor the concentration of CO, NO and O2 and in some cases CO2 and SO2 inside the kiln close to the raw material inlet under extreme conditions such as:
SICK provides for these conditions the optimal sampling and analyzing systems. Our solution:
In addition to the rotary kiln, modern cement plants are equipped with a multistage cyclone pre-heater and a pre-calciner. The pre-heater is using the excess heat from the kiln and the pre-calciner. Pre‑heating and pre‑calcining of the raw material shorten the sintering process in the kiln, the overall fuel consumption is reduced. Control parameters at the pre-heater are CO, NO, O2 and SO2. Our solution:
MKAS analyzing system with SIDOR analyzer
For environmental compliance the exhaust gases from the production processes have to be dedusted. In addition, the dedusting processes are used for material recovery ( e.g. in the coal mill). Electrostatic precipitators are commonly used for dedusting of the hot exhaust gases from pre-heater, pre-calciner and kiln. For cold exhaust gases (from coal mill, etc.) and for material recovery bag filters are used. In order to detect bag leaks and to ensure compliance with the relevant emission limits SICK dust analyzers are used. Our solution:
DUSTHUNTER SP100 dust monitor
The efficiency of an electrostatic precipitator is strongly depending on the conductivity of the dust particles. In the pre-heater, the dust particles are humidified to increase conductivity. The sprayer intensity is controlled by continuously monitoring the gas volume flow. Our solution:
FLOWSIC100 gas flow monitor
To protect the electrostatic precipitator (ESP) from electric sparks or explosions a fast CO measurement at the filter inlet is required. In case of CO peaks, the filter can be shut down in time and be prevented from serious damages. For ESP protection SICK offers an extractive solution with optimized resonse behavior. Our solution:
Extractive measurement: MKAS analyzing system with SIDOR analyzer
Depending on the kind of fuel used and local environmental regulations, a number of pollutants, preferably CO, NOx and SO2 are to be monitored continuously in the flue gas at the stack along with dust (particulate matter, PM), gas flow, and the reference values H2O, temperature and O2. The monitored data is transferred to a specific data acquisition system for further processing and reporting to the authorities. In case of co‑incineration of alternative fuels, additional components such as HCl, HF, Hg and TOC may be required to be monitored as well. Monitoring equipment used for CEM applications must be approved by the government (for example Waste Incineration Directive 2000/76/EC), precondition is an approval test according to EN 15267-3, and fulfilling the quality standard EN 14181. Our solutions: