Abstract: SICK MAIHAK GmbH, an analytical technology expert, provides a wide range of process control equipment for cement plants. 1. Introduction Currently, approximately 1.8 billion tons of cement are produced globally at the cost of high energy costs and the generation of large amounts of CO2, COx, and dust. Rising energy prices and stringent safety and environmental requirements make reliable process control particularly important: it can reduce problems and ensure the economical use of raw materials and fuels. SICK MAIHAK GmbH, an analytical technology expert, has a broad product range and global service capabilities, providing testing services for the cement industry under both necessary and challenging conditions, and offering complete sets of customized analytical equipment for cement plant operators. Every step of the production process requires monitoring, and most of it is related to gas and dust emissions. After the pre-drying stage, the raw materials need to be ground together with additives from the beginning and stored in silos as cement raw meal. Rotary blade switches or hammer level indicators manufactured by SICK MAIHAK are used to prevent material blockage and overloading. The same situation can be avoided when the final cement clinker is mixed with additives used to produce different types of cement, stored in the silo, and then transported on the conveyor line later in the process, resulting in blockages and overloading. Between these two processes lies the calcination process, which is mostly carried out in the preheater tower (with or without a preheater) and rotary kiln. 2. Special Probes The preheater tower is the most important sampling point, where raw materials are dried and pre-decomposed at continuously rising temperatures. CO, CO2, and O2 are monitored here to regulate secondary combustion in the preheater tower and preheater. High temperatures, high dust concentrations, and low pressure make detection extremely difficult. At the top of the preheater tower, where temperatures reach 400°C, SICK MAIHAK recommends installing a reflux probe with an inlet filter and an extraction detection device. A cooling sampling probe, such as the SCP3000, is needed in the lower-stage cyclone or preheater area where temperatures reach 1000°C. Even under such challenging conditions, this probe provides accurate detection, despite the rapid drop in O2 in this area. CO2/O2 detection in the preheater tower can be extended to the analysis of NO gas. To reduce NO emissions, it allows for optimized control of secondary combustion. Monitoring of primary combustion (coal, oil, or natural gas) and cement quality is required at the rotary kiln inlet, where detection conditions are extremely challenging, with gas temperatures reaching 1400°C and dust concentrations as high as 2 kg/m³. To prevent clogging, wear, and raw material falling onto the probe, the SCP 3000 gas sampling system, with its water-cooled probe, is ideally suited for this application. The extraction device consists of a probe with a filter, mounted on a telescopic device for easy removal from the furnace. A rotating mechanism ensures raw material is shaken out of the probe at regular intervals. An automatic reflux device controlled by compressed air increases the efficiency of the probe and filter. For subsequent analysis, SICK MAIHAK offers analytical cabinets specifically designed for the cement industry, equipped with the MKAS 710-C unit of the S710 standard system. For direct detection of high SOx gases, the MCS 100E HW analytical cabinet is most suitable. The company has the capability to provide optimized analytical devices for different process conditions (e.g., waste tire incineration). [align=center] Figure 1 MKAS 700 Analytical Cabinet[/align] 3. Smoke drying is easier for testing in wet-process cement production. Because the entire calcination process takes place in a rotary kiln, all the moisture in the slurry must be evaporated, thus consuming twice the energy compared to dry-process production. The temperature at the rotary kiln inlet is only about 150°C; however, due to the rotation of the raw slurry, the flue gas becomes a problem here. These gases must be controlled using extended drying sampling tubes and reflux probes. A suitable drying adapter can dry the smoke before it reaches the filter. [align=center] Figure 2 SCP 300 Gas Sampler[/align] The calcined clinker is cooled to 300–100°C. The hot gas generated during the cooling process can be used as preheating air for the burner or to dry the raw meal or coal. Depending on its intended use, dust in the clinker must be removed first. The filter is monitored using a dust monitor (FW 56) and a level indicator (Maihak MBA200). Dust from the preheater tower and other areas of the plant must also be removed. For this purpose, the electrostatic precipitator must be protected against explosion by monitoring the inlet CO concentration; the GM950 in-situ analyzer is most suitable. To prevent dust accumulation, the filter is monitored using a level indicator. To control the hydration of the inlet gas of the electrostatic precipitator, the FLOWSIC100 volumetric flow meter is suitable. 4. Explosion Protection: If the cement plant uses coal as fuel, extra caution is required. When grinding wet coal, the accumulated coal dust poses a risk of spontaneous combustion; using inert gas can eliminate this hazard. Monitoring can be achieved by detecting the oxygen concentration in the mill and exhaust gas before dust removal. A rapid positioning analyzer (ZIRKOR302) or an extraction device equipped with an analyzer (S700) is ideal. If CO concentrations in the mill, dust collector, pulverized coal silo, or coal hopper are monitored simultaneously, the S700 analyzer is most advantageous because it can detect fires at an early stage. Changes in CO concentration indicate an impending fire hazard. Dust from the coal hopper, coal mill, and coal mill dust collector can be detected using Maihak MBA200 and/or Maihak LOT369 level indicators. The FW56 dust monitor is responsible for monitoring the efficiency of the dust collector system. 5. Emission Monitoring Emissions from the entire plant must be monitored according to the regulations stipulated by the environmental protection company. In Germany, the standards stipulated by TA-Luft apply, or if waste is burned, the standards valid under IEC 2000/76 of the European Community apply. In North America, NOx monitoring is emphasized, while in the Far East, HCl emissions are often monitored when waste is burned. For emission monitoring of systems burning conventional fuels, SICK MAIHAK offers extraction (MKAS 710) and location-based detection technologies (GM31, GM35). For waste incineration plants, it is recommended to use an extractive MCS 100E HW analyzer, combined with THC (Euro FIB) for mercury detection (MERCEM). Measuring reference values ​​(O2, volumetric flow rate, pressure, temperature) and dust, as well as collecting and evaluating MEAC2000 detection values, provides a complete emissions monitoring system.