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Phase separation

Benefits for the user include:

  • immediate detection of phase transitions (response time less than 1 s)
  • replacement of manual, visual or indirect detection methods (e.g. timing)
  • improvement of the product yield
  • saving of energy and material costs
  • optimal plant control through online information about the state of the process
  • increased plant reliability by continuous monitoring

Using the latest digital signal processing technology ensures a highly accurate and fail-safe measurement of the absolute sonic velocity and the concentration. 

In addition, integrated temperature sensors, a sophisticated sensor design and the know-how resulting from numerous series of measurements and many applications guarantee a high reliability of the system with a long lifetime.

Advantages of the measuring method are:

  • absolute sonic velocity as a well-defined and retraceable physical value
  • independent of color, conductivity and transparency of the process liquid
  • installation directly into pipelines as well as tanks or vessels
  • robust and completely metallic sensor design without gaskets or moving parts
  • maintenance-free
  • corrosion resistance by using special material
  • use at temperatures up to 200 °C
  • high, drift-free measuring accuracy even with high concentration of gas bubbles
  • connection of up to four sensors per controller
  • forwarding of measuring results through fieldbus (Profibus DP, Modbus), analogue outputs, serial interface or Ethernet

1. Process

1.1 Phase separation in pipelines

The precise detection of different phases in a pipeline is necessary in various industries. Often different products flow through the same pipe, but every single product is supposed to end in a different location. 

In applications in which product A is discharged by product B, the intermediate phase is to be separated. For example, in breweries, different kinds of beer are bottled in succession, whereas the first and last runnings are removed from circulation and return into the brewing process. 

Safety aspects are relevant in applications with high-risk potential. In particular, the monitoring in multi-fuel pipelines for the petrochemical industry provides not only data about the product quality (incoming goods), but also avoids incorrect filling of storage tanks and thus serious accidents. 

In the petrochemical industry, different fuels are conveyed over very long distances in just a pipeline. Here the rapid detection of the different products as well as the quality monitoring are focused.

1.2 Phase separation in batch processes

In batch processes the product phases are separa-ted due to the physical and chemical properties of each product. 

Application example 1: organics
In the production of cosmetics, a salt-containing aqueous phase is separated from an primary pro-duct phase. The aqueous lower phase is disposed via sewage-works. The upper phase of the primary product is slightly hazardous to water and only moderately biodegradable. Therefore, this phase must not be discharged into sewage. The rapid and reliable detection of the primary product phase has the highest priority to prevent discharging into the effluent via an immediate shutdown. 

Optical measuring methods may not be used here, because different colours may occur during the phase separation. In addition, a mixed layer may form, which can be critical for the optical measure-ment due to contamination effects.

Application example 2: biodiesel / glycerol 
In the manufacture of biodiesel, glycerol is produced as a by-product. The mixture of the two substances is conveyed in large settling tanks and then has several hours to separate. The LiquiSonic® sensors are usually installed into the outlet of the tank. By the detection of the phase transitions, the valve is activated and the biodiesel and the glycerol is supplied to the processing. The intermediate phase returns to the separation process.

Application example 3: integrated valve solution 
Various vessel configurations such as agitators, double casing features or coatings prohibit the integration of additional sensor technology. Therefore, SensoTech developed with a fsmous manufacturer of bottom outlet valves (BOV) a sensor solution that is integrated directly into the valve disc. So the only existing process connection at the outlet will be used optimally. The sensor detects the phases directly at the drain of the vessel. That means, the detection takes place in the vessel, so there is no dead space.

1.3 Phase separation in continuous processes

In a continuous process, one or more sensors control the separation of a process stream. In this case, only the phase-specific value of sonic velocity is monitored and kept constant. 

Often, the product concentration of the carrier pha-se varies in the inlet. This quickly shifts the height of the phase boundary. Thus, the carrier phase could be pulled off with the product, which greatly affects the purity. 

In process the separation is made via one pump in each of the two outlet pipes. In this way, for example, the continuous separation of a reaction mixture can be controlled. The advantages of the LiquiSonic® measuring and analyzing technology are both the extremely fast response time of less than 1 s and the connection of up to four sensors to only one LiquiSonic® controller. The controller processes all measuring values and passes the data to the process control system.

Depending on the type of vessel and process objectives different installation variants are possible, which are shown in the illustration below.

Installation variant 1 
Most commonly, the sensors are installed on the side of the vessel. The requirement of the central sensor (measuring point 2) depends on the application and the forming of the intermediate phase.

Installation variant 2 
By the use of a single sensor of a length of up to  4 m, the phase profile of the entire vessel can be determined. By mounting the sensor on a movable carriage, for example, and in combination with a distance meter, the phase boundaries can be accu-rately determined in their current height.

Installation variant 3 and 4 
In vessels in which connections are not provided at the side or cannot subsequently be realized, the sensors are positioned directly in the vessel or by using a submerged tube in the right place, for example at heated double jacket vessels. Using a submerged tube, the sensor electronics are moun-ted apart at a distance of up to 15 m to the vessel.

2. LiquiSonic® system

2.1 LiquiSonic® 30

The LiquiSonic® 30 system consists of one or more senors and one controller.

Each sensor works autonomously and can be used in different applications. The liquid-wetted parts of the sensor are made of stainless steel DIN 1.4571 as standard. In chemical aggressive liquids the sensor is made of special corrosion-resistant material. The rugged, completely enclosed design requires no gaskets or “window”, making it totally maintenance-free. 

Additional sensor features such as flow / stop or full / empty pipe monitoring greatly advance process control. The LiquiSonic® high-power technology stabilizes measuring results, even when facing gas-bubble accumulations or large-scale signal attenuation through the process flow.

The special sensor electronics is integrated in a closed die-cast housing with a protection degree of IP65. If necessary, the electronics housing can be mounted apart from the sensor. 

The data can be transmitted in several defined analog or digital forms or through different fieldbus interfaces to communicate with process control systems or computers. 

The controller features an integrated data logger which can store up to 2 GB of process information with up to 32 (optional 99) data sets for different process liquids. For processing on the PC, the data can be transferred via network or USB port. In addition, the controller enables creating easily process reports for documentation purposes. The event log records states and configurations such as manual product switches, alarm messages or system states.

2.2 Accessories

2.2.1 Controller and field housing

The controllers are designed for rack-mounted systems. It is also available with a 19“ housing 3RU. 

In order to be able to mount controllers into the field, two variants of field housings made of plastic or stainless steel can be delivered, which meet on-site conditions in an optimal way.

2.2.2 Fieldbus

The fieldbus option provides the possibility to integrate the controller in a PCS or to automate the process flow via PLC. Beside the transfer of measuring values like concentration and temperature it is also possible to exchange parameters and control data (for example product switch). 

The controller supports different fieldbus systems and follows the standards recommended by the respective standards organizations. Common variants are Modbus and Profibus DP.

3. Quality and support

Enthusiasm for technical progress is the driving force behind our company as we seek to shape the market of tomorrow. As our customer you are at the centre of all our efforts and we are committed to serving you with maximum efficiency. 

We work closely with you to develop innovative solutions for your measurement challenges and individual system requirements. The growing complexity of application-specific requirements means it is essential to have an understanding of the relationships and interactions involved. 

Creative research is another pillar of our company. The specialists in our research and development team provide valuable new ways to optimize product attributes, such as testing new types of sensor designs and materials or the sophisticated functionality of electronics, hardware and software components. 

Our SensoTech quality management also only accepts the best production performance. We have been certified according to ISO 9001 since 1995. All device components pass various tests in different stages of production. The systems have all gone through an internal burn-in procedure. Our maxim: maximum functionality, resilience and safety. 

This is only possible due to our employee`s efforts and quality awareness. Their expert knowledge and motivation form the basis of our success. Together we strive to reach a level of excellence that is second to none, with a passion and conviction in our work. 

Customer care is very important to us and is based on partnerships and trust built up over time. As our systems are maintenance free, we can concentrate on providing a good service to you and support you with professional advice, in-house installation and customer training. 

Within the concept stage we analyse the conditions of your situation on site and carry out test measurements where required. Our measuring systems are able to achieve high levels of precision and reliability even under the most difficult conditions. We remain at your service even after installation and can quickly respond to any queries thanks to remote access options adapted to your needs. 

In the course of our international collaboration we have built up a globally networked team for our customers in order to provide advice and support in different countries. We value effective knowledge and qualification management. Our numerous international representatives in the important geographical markets of the world are able to refer to the expert knowledge within the company and constantly update their own knowledge by taking part in application and practice-oriented advanced training programs. Customer proximity around the globe: an important element of our success worldwide, along with our broad industry experience.

Innovative sensor technology

SensoTech is a provider of systems for the ana-lysis and optimization of process liquids. Since our establishment in 1990, we have developed into a leading supplier of process analyzers for the inline measurement of liquid concentration and density. Our analytical systems set bench-marks that are used globally. 

Manufactured in Germany, the main principle of our innovative systems is to measure ultrasonic velocity in continuous processes. We have perfected this method into an ext-remely precise and remarkably user-friendly sensor technology. Beyond the measurement of concentration and density, typical applications include phase interface detection or the monito-ring of complex reactions such as polymerization and crystallization. 

Our LiquiSonic® measuring and analysis systems ensure optimal product quality and maximum plant safety. Thanks to their enhancing of effi cient use of resources they also help to reduce costs and are deployed in a wide variety of industries such as chemical and pharmaceutical, steel, food technology, machinery and plant engineering, car manufacturing and more. 

It is our goal to ensure that you maximize the potential of your manufacturing facilities at all times. SensoTech systems provide highly accurate and repeatable measuring results even under difficult process conditions. Inline analysis eliminates safety-critical manual sampling, offering real-time input to your automated system. Multi-parameter adjustment with high-performance configuration tools helps you react quickly and easily to process fluctuations. 

We provide excellent and proven technology to help improve your production processes, and we take a sophisticated and often novel approach to finding solutions. In your industry, for your applications – no matter how specific the requirements are. When it comes to process analysis, we set the standards.