Online carbon-sulfur analyzer

Product Overview

The ITECA online carbon–sulfur analyzer is a fully automated, in-line quality‑control instrument specifically designed for the cement grinding stage. It addresses the core requirements of automatic sampling of finished cement after grinding, sample pretreatment, rapid carbon–sulfur analysis, and real-time data feedback, replacing traditional manual sampling and laboratory‑based offline chemical analysis. This enables unmanned operation across the entire workflow—from sampling and sample delivery to sample preparation and high‑temperature combustion infrared analysis.

The product is deeply aligned with the digital transformation needs of smart cement plants, seamlessly integrating with DCS systems and cement batching optimization software. It provides high‑frequency, real‑time SO₃ and CO₂ measurement data for adjusting clinker, gypsum, and blended material ratios, enabling precise estimation of gypsum dosage and the proportion of blended materials. By addressing longstanding industry challenges—such as the lag inherent in manual testing, poor sample representativeness, and significant labor costs—it serves as a core online quality‑control solution for ensuring stable cement quality at the plant outlet and optimizing grinding‑related economic efficiency.

Industry Pain Points and Application Requirements

In the cement grinding process, sulfur trioxide (gypsum) and carbon dioxide (mineral admixtures) are key parameters for controlling cement setting time, final‑product strength, and the economic viability of admixtures. However, the conventional manual offline testing approach faces multiple bottlenecks:

1. Strong detection lag: The entire process—collecting ground‑material samples and sending them to the laboratory for ignition‑loss analysis—takes a considerable amount of time. Moreover, after adjustments to the raw‑material mix, data feedback is severely delayed, making it impossible to promptly regulate the feed rates of clinker, gypsum, and blended materials.
2. Poor sample representativeness: Manual single-point sampling fails to capture the entire cross-section of the chute, leading to sample segregation and distorted analytical results, while the grade‑control pass rate remains persistently unstable.
3. High labor and time costs: It requires laboratory technicians to conduct regular, scheduled sampling, sample preparation, and ignition‑based analysis, resulting in a cumbersome workflow that consumes substantial manpower at the analytical workstations.
4. Lack of an intelligent closed loop: Offline measurement data cannot be integrated into the batching optimization system in real time, forcing post‑hoc, reactive adjustments to mix proportions and making fully automated, intelligent control of the grinding process difficult to achieve.
5. Limited economic benefits: Fluctuations in gypsum content can easily lead to abnormal cement setting, and the dosage of blended materials cannot be precisely controlled, making it impossible to maximize the proportion of admixtures and reduce production costs while remaining compliant.

As the cement industry accelerates its digital and intelligent transformation, high‑frequency, fully automated online carbon–sulfur analyzers have become essential equipment for the smart upgrade of cement grinding units.

Core Technological Advantages

1. Full‑section helical sampling ensures high sample representativeness: A variable-pitch helical sampler is employed to fully cover the cross-section of the discharge chute, eliminating sampling blind spots. Paired with a piston‑driven secondary reduction mechanism, it mitigates measurement errors caused by material segregation.
2. High-frequency continuous monitoring, compatible with dynamic ingredient adjustment: A single unit can serve two cement mills, performing up to five carbon–sulfur analyses per hour. High‑frequency data is matched in real time to mill feed fluctuations, enabling real‑time fine‑tuning of the batching process.
3. End-to-end automation, fully unmanned operation: Automated sampling, scrap material reclamation, sealed conveying, reagent addition, high‑temperature combustion, infrared detection, and residue removal are all performed automatically by a robotic system, eliminating the need for manual intervention, minimizing human error, and significantly reducing the laboratory’s workload.
4. Multi-system data interoperability enables a closed-loop formulation process: Standard configuration includes 4–20 mA, Modbus, and Prefinet communication interfaces; measurement data is uploaded in real time to the central DCS and batching optimization software, which automatically generates proportioning adjustment parameters, enabling intelligent closed-loop control of the grinding system.
5. Adaptable to multiple operating conditions, ensuring long-term stable industrial operation: The system features a fully modular design, equipped with automated dust removal, crucible self‑cleaning, and residual material recovery systems, enabling 24‑hour continuous operation. Its sampling and conveying mechanisms are tailored to handle cement dust and highly abrasive conditions, having undergone long‑term industrial validation on multiple domestic cement production lines, ensuring stable and reliable performance.
6. Dual‑parameter simultaneous output from a single device: A single analysis simultaneously measures carbon and sulfur content, enabling rapid calculation of the blending‑material and gypsum addition rates; one system covers the two key quality‑control parameters in the grinding process.

System Composition

The ITECA online carbon–sulfur analysis system features a modular, split‑design architecture, comprising three core modules: a sampling unit, a sample‑transfer system, and the main carbon–sulfur analyzer. It offers flexible installation and convenient on‑site operation and maintenance.

1. Sampler Unit: Each mill is equipped with an independent screw‑type sampling system, integrating a variable‑pitch screw sampler, a piston‑type secondary sampler, a rapping motor, a residual‑material recovery pipeline, and an on‑site control cabinet. Installed on the inclined chute or bucket‑elevator chute downstream of the cement mill, it enables automated sampling and quantitative sub‑sampling of finished cement, while automatically returning excess material to the production line. A dedicated sample‑retention branch is provided in parallel to meet routine physical‑ and chemical‑analysis sampling requirements.
2. Transmission System: It consists of a sealed conveying pipeline, a power-driven blower, and a buffer hopper. For short distances, material is discharged by gravity; for conveying distances exceeding 5 m, it can be equipped with a chain‑type zip conveyor for horizontal transport, with a maximum conveying distance of 20 m. The entire system is fully enclosed, preventing dust leakage and protecting the sample from moisture and contamination.
3. Analyzer Unit: It integrates a crucible storage rack, an automated reagent‑addition unit, a high‑precision electronic weighing module, a 1300°C high‑frequency combustion furnace, an infrared gas analyzer, a cleaning robotic arm, and a PLC‑based intelligent control system, enabling fully automated execution of the entire workflow: sample weighing, flux addition, high‑temperature combustion, gas analysis, automatic removal of residues, and data processing and output.

Detection Principle

The instrument employs high-frequency induction–high-temperature combustion coupled with infrared absorption detection, ensuring a stable and highly efficient analytical process.

The cement sample exiting the mill is collected via a screw sampler, subjected to a two-stage reduction process, and then conveyed in a sealed stream to the analyzer. The instrument automatically and accurately weighs out 1.0 g of the standard sample.

The system automatically adds iron and tungsten fluxes, feeds the charge into a high‑temperature induction furnace, introduces 99.5% pure oxygen, and raises the furnace temperature to 1300°C.

In the sample, gypsum decomposition releases SO₂/SO₃, while the decomposition of reactive carbonate admixtures releases CO₂; the resulting gas mixture is then fed into the infrared detection unit.

Infrared analyzers measure the concentrations of CO₂ and SO₃ gases, while the system’s built-in proprietary algorithms convert these measurements into the total carbon and total sulfur contents of the sample, enabling more precise estimation of gypsum content and the proportion of active mineral admixtures.

This measurement principle has been extensively validated in numerous industrial projects across the global cement industry, offering a wide measurement range and excellent repeatability, fully aligning with the online control standards for cement grinding and batching.

Application Value and Benefits

1. Stabilize the quality of finished cement: Real-time carbon and sulfur data dynamically adjust the proportions of clinker, gypsum, and blended materials, rigorously control the sulfur trioxide content, stabilize cement setting time and strength, and significantly improve the pass rate of outgoing cement.
2. Optimizing production costs: Precisely control the maximum compliant blending ratio of supplementary materials, reduce clinker consumption, stabilize gypsum addition, minimize raw material waste, and significantly lower the overall grinding production cost.
3. Reduce headcount and boost efficiency, lowering the labor burden: Eliminates the need for laboratory technicians to perform routine on-site sampling and offline ignition‑based analysis, reduces manpower requirements at the analytical workstation, and mitigates the physical strain associated with on-site dust‑exposure work.
4. Reducing the risk of production fluctuations: Detect anomalies in gypsum and blended material parameters in advance, and adjust the feeding equipment proactively to prevent the production of non‑conforming cement batches.
5. Enhance the smart factory management and control system: Address the shortcomings in online real-time monitoring within the grinding section, establish end-to-end data connectivity across the entire process—from raw materials to grinding and finished products—and support closed-loop intelligent control of the cement production line.