In limestone-gypsum FGD (flue gas desulfurization) systems, online pH analyzers are used to control the consumption of a desulfurization agent (lime). The heavy lime scaling on the pH electrode is of great concern in the pH measurement. Frequent cleaning of the electrodes with acid is required to ensure accurate measurements, adding to the maintenance workload and cost. The SENCOM technology provides predictive maintenance, and FU20-FTS can withstand the harsh conditions of the scrubber. SENCOM™ features real-time diagnostics, sensor wellness for early detection of sensor failure and replacement, and proactive maintenance. So it saves both time and expense and, at the same time, ensures precise pH measurement over long periods.
– Improves the efficiency of a limestone-gypsum flue gas desulfurization system
– Ensures stable, continuous pH measurement
– Reduces operating costs
– Provides predictive maintenance
The limestone-gypsum flue gas desulfurization consists of two processes: absorption and oxidation.
Reaction formula; Ca(OH)2 + CO2 -> CaCO3 + H2O, 2CaCO3 + 2SO2 + 1/2H2O -> 2CaSO3·1/2H2O + CO2
In this process, it is crucial to promote the reaction of calcium (Ca) and to achieve a target desulfurization rate. The liquid’s pH, concentration, temperature, and liquid/gas ratio affect the absorption rate. When the pH of the absorbing solution is below 5, calcium hydrogen sulfite (Ca(HSO3)2) is generated. Ca(HSO3)2 is converted into sulfur dioxide (SO2) in a reversible reaction, lowering the desulfurization rate. When the pH of the absorbing solution is 7 or higher, carbon dioxide (CO2) in the flue gas reacts with calcium (Ca) to produce calcium carbonate (CaCO3). This increases lime consumption. Since pH influences the subsequent oxidation process, the pH of the absorbing solution should be kept between 5 and 6.
Reaction formula: CaSO3·1/2H2O + 1/2O2 + Aq -> CaSO4·1/2H2O + Aq
In this process, calcium sulfite (CaSO3·1/2H2O) from the absorption process is oxidized with air to calcium sulfate (CaSO4) under about 500 kPa pressure and 50 to 80 °C temperature. The pH of the absorbing solution in the absorber is around 6. It should be kept at about 4 by adding acid from the cooling tower.
Deposits of crystalline substances (e.g., CaCO3) on electrodes in limestone-gypsum flue gas desulfurization systems decrease the accuracy of pH measurements. Because of the design of FU20 sensors, the lifetime of the sensors will be higher. And also, cleaning the electrodes and reducing maintenance time and cost are key points to consider when selecting a pH analyzer for the system. /HCNF option of FU20 sensors for cleaning can be suggested for easy maintenance. Acid cleaning is done with a 5% hydrochloric acid solution.
FLXA202 /FLXA21 2-wire pH/ORP measurement system; General purpose, Intrinsic safety
FLXA402 4-wire pH/ORP measurement system; General purpose
SENCOM™ Smart Adapter (optional)
The reusable smart adapter, SA11, offers full measuring parameter functionality of analog sensors equipped with a Variopin connector and Yokogawa ID chip. The SA11 automatically recognizes the installed sensor and prepares the proper configuration. SENCOM™ technology allows sensors to transmit and receive data when connected to a transmitter/analyzer or a PC. The SMART digital sensors maintain specific measurement and calibration data on an integrated chip that is an integral part of the sensor, providing easy plug-and-play solutions.
Option 1: FU20-FTS Differential pH/ORP sensor
Differential sensor technology is unique to the industry. In this type of sensor, the reference cell is made of glass with no porous junction. No electrolyte is in contact with the process, ensuring a stable measurement and virtually maintenance-free. These sensors are intended for inline aggressive and harsh process control applications with some sodium content.
1. Extended sensor lifetime
2. Less maintenance requirement
3. No electrolyte depletion
4. Unaffected by the pressure changes
5. Less reliance on pH-regulating chemicals
*Calibration of differential pH sensors: A differential pH sensor needs pH buffers with the same ionic strength as the sodium reference because the sodium reference will change as the ionic strength changes. Yokogawa can supply these specific pH buffers, please check spare parts at GS 12B06J03-05EN-P
Option 2: FU20-NPT pH/ORP Combination sensor
The FU20 combination sensor shows how Yokogawa applies the motto “Simply the best” to sensor technology. The wide body sensors (26 mm diameter) hold four unique elements in one unbreakable PPS40GF (RytonTM) or PVDF body. Installation is simple with the integrated industrial 3/4” tapered thread. The large volume of gelled electrolyte and the double junction reference system slow down depletion and poisoning, extending the lifetime. The system is targeted at those applications where simplicity will result in accurate and reliable pH- or redox measurements. This sensor will be an excellent choice in 90% of the known applications.
1970년대 중반, Yokogawa는 EBS 전기 제어 시스템 (EBS Electric Control System)의 출시와 함께 전력 사업에 진출했습니다. 그 이후로 Yokogawa는 전 세계 고객에게 최상의 서비스와 솔루션을 제공하기 위한 기술과 역량의 개발을 꾸준히 지속해 왔습니다.
Yokogawa는 역동적인 글로벌 전력 시장에서 더욱 적극적인 역할을 수행하기 위해 글로벌 전력 솔루션 네트워크를 운영했습니다. 이로 인해 Yokogawa 내에서 보다 긴밀한 팀워크가 가능해져서 글로벌 리소스와 업계 노하우를 하나로 모았습니다. Yokogawa의 전력 산업 전문가들은 각 고객에게 정교한 요구 사항에 가장 적합한 솔루션을 제공하기 위해 협력합니다.
The FLEXA™ series analyzers are used for continuous on-line measurements in industrial installations. With an option for single or dual sensor measurement, they are the most flexible two-wire analyzer available.
FLEXA ™ 시리즈 분석기는 산업용 설비의 연속 온라인 측정에 사용됩니다. 단일 또는 이중 센서 측정 옵션이 있어 가장 유연한 2 선식 분석기입니다.
PH20, FU20, FU24는 올인원 타입의 pH 와 ORP 센서로서 Yokogawa가 "Simple is best" 이라는 모토를 센서 기술에 어떻게 적용하는 지를 보여줍니다.
Reusable SMART adapter, requiring only the analog sensor to be disposed of when it reaches the end of its lifetime. With the SENCOM 4.0 platform, Yokogawa delivers reduced costs and waste while contributing to its long-term business goals of a sustainable future for all.
pH 전극 및 센서는 pH 측정의 감지 부분입니다. Retractable, flow-though, 침적 및 직접 삽입을 포함한 다양한 설치 옵션이 있습니다.
적절한 pH 전극 / 센서 선택은 최적의 측정 결과를 위해 중요합니다.