Accurate relative humidity and temperature measurement plays a critical role in the production and storage of chemicals in liquid and powdered form. The measurement instruments used in these processes must be able to cope with harsh conditions including high temperatures. When selecting your measurement technology, as well as reliability and accuracy it is also important to consider the lifetime cost and available installation options. 

Improve the efficiency of chemical drying

Drying processes like vacuum drying, commonly used in chemical processing industries, require accurate relative humidity and temperature measurement to operate energy efficiently. These kinds of processes are challenging because of the high temperatures and harsh chemicals involved, so the measurement technologies used must be robust enough to operate reliably in these conditions. 

Vaisala’s offering includes pressure-tight humidity and dew point instruments that are built to withstand high temperatures, providing stable, drift-free measurement. Instruments with Vaisala HUMICAP^® and DRYCAP^® technologies also include a chemical purge feature. This feature is useful when the sensor is exposed to solvents and vapors that may enter the polymer and change the sensor’s electrical properties. This manifests itself to the user as sensor drift. Chemical purge restores proper sensor performance by rapidly heating the humidity sensor, driving off any gas molecules that occupy the sensor’s polymer. Chemical purge can be initiated manually, or it can be set to run automatically at user defined intervals. For more information on the chemical purge feature, read this scientific paper.
 

Secure end-product quality through optimal storage conditions

The longer a chemical product is stored, the more important it is to ensure the storage conditions are optimal. Accurate and reliable humidity and temperature monitoring in chemical storage facilities is vital for safety reasons and to secure end-product quality. Many chemicals are sensitive to humidity – for example, some chemicals may react with water, causing the release of toxic vapor or even an explosive chemical reaction. 

Non-optimal humidity can also cause some powdered chemicals to form lumps, a phenomenon known as caking, which can cause problems with transportation and usage.
To make chemical storage monitoring as easy as possible, Vaisala offers a wide range of temperature and humidity probes that can be wall mounted and include an exchangeable probe to make maintenance quick and easy. 
 

Ensure safe use of glove boxes, reaction chambers, and vacuum chambers 

Humidity and temperature monitoring also help to increase safety when handling chemicals that are moisture or temperature reactive, either in glove boxes or when processing them in reaction chambers or vacuum chambers. For example, instruments with Vaisala DRYCAP® technology can be used in glove boxes to monitor and control the conditions inside the box. These instruments offer long-term stability, fast response times, and include a chemical purge feature to ensure they maintain high accuracy.

Easy data storage and access with cloud-based technology

Humidity and temperature measurements performed with Vaisala probes can be conveniently stored and accessed using the Vaisala Jade Smart Cloud system. The system allows you to log data, store it real-time, and access it from any location using a mobile device.

The key benefits of the system include:

• Scalability: As a modular system, Jade Smart Cloud can be scaled easily for a variety of purposes. Users can simply set up as many loggers and access points as they need and add more as their needs change. 
• Cloud storage: All data collected is stored in the cloud, meaning there’s no need to worry about IT infrastructure, security, system maintenance, or setting aside server space for data storage.
• Extremely good radio connectivity: Jade Smart Cloud’s wireless connectivity is based on LoRa radio technology, which is already widely respected. Vaisala has pushed it even further with modified features to ensure that it meets our customers’ most demanding requirements.
• Regular firmware updates: Jade Smart Cloud’s software updates automatically, with no action needed from the end user as the new firmware version is installed directly onto the local system from the cloud.
• Vaisala HUMICAP® sensors: Because the system uses proven HUMICAP sensors, it provides extremely stable and high-quality measurements.

Learn more about the Jade Smart Cloud system.

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Save costs and energy, and improve process control with accurate measurement of liquid chemical concentration

The concentration of liquid chemicals may change several times during processing. Typical processes include the following:

• Mixing/blending/reaction: The objective of the reaction process, where ingredients are continuously mixed in a series of static mixers, is to achieve the final required value of a product. An example application is detergent blending.
• Filtration/separation: Filtration is used to separate undissolved particles from a liquid, beginning with coarse filtration using separators, decanters, or settling tanks and ending with final polishing. The efficiency of the filtration process impacts the overall productivity. An example application is pure water treatment with chemical precipitation.
• Verification/quality control: Controlling a product’s composition helps to ensure high-performance materials with exactly the right properties. Maintaining consistent quality can lead to substantial savings. Precise product concentrations also minimize the need for further treatment. An example application is product quality control in the polymerization process.
• Distillation/dilution: Distillation is used to separate alcohol from a fermented product and to separate different alcohols – such as methanol, ethanol, and propanol – from each other. Many concentrated chemicals also need to be diluted before use. The dilution process can be monitored in the tank or in a circulation line. Concentration measurement is a vital tool when performing dilution. An example application is the autoxidation process in hydrogen peroxide production.
• Product identification: For safety reasons and to avoid cross-contamination, it is critical to ensure that the right chemical is fed to the right tank during loading, unloading, or custody transfer. In-line Vaisala process refractometer differentiates chemicals in liquid form based on their distinctive refractive index. An example application is the chemical interface identification in loading/ unloading operation. 

The in-line process refractometer can be used to provide real-time measurements of liquid concentration in all these processes. The technology eliminates the need for time-consuming manual sampling and the risk of measurement drift due to, for example, turbulence. The technology is low maintenance, with no moving parts that require regular replacement, meaning it has a low cost of ownership compared to density meters.
Learn more by watching our webinar: All you need to know about in-line liquid concentration and density measurement.

Furthermore, the in-line process refractometers can withstand corrosive chemicals and high temperatures thanks to their digital measurement principle, and measurements are not affected by air bubbles or the color of the liquid being measured. If needed, a wash system can also be included to keep the prism clean, thereby ensuring accurate measurement.

Discover the technology behind the Vaisala HUMICAP® and DRYCAP® technologies used in Vaisala’s humidity probes, and learn more about Vaisala in-line process refractometers.

This blog is first in a three-part series on how in-line process refractometers can optimize API processes.

The creation of Active Pharmaceutical Ingredients (APIs) is a critical part of pharmaceutical production. API formulation typically begins with loading chemicals into a reactor where chemical bonds are broken, and new bonds formed. After reaction, the active ingredient is separated through downstream purification steps, such as centrifugation and filtration. Typically, the API is recovered as a solid from the liquid phase and the solvent used is recovered in dedicated solvent recovery units.  Solvent recovery is important in the pharmaceutical industry because it helps to reduce costs and environmental impact. The final API solid is then dried before it can be used as an intermediate or to formulate the final drug product.

Developing and optimizing pharmaceutical manufacturing processes can be a complex and lengthy process, taking several years to complete. In order to streamline these processes and bring drugs to market faster, it is important for pharmaceutical companies to focus on creating efficient processes that are scalable and reproducible at a commercial scale. The implementation of the FDA’s Process Analytical Technology (PAT) framework, including the use of in-line measurement instrumentation, offers a valuable opportunity for pharmaceutical process development and scale-up through the collection and analysis of data for process understanding, design and optimization. PAT tools help to ensure quality is integrated into the design and that processes produce products of consistent quality that meet the required specifications. 

Using refractive index as part of PAT

Refractive index (RI) has proven to be a useful Process Analytical Technology (PAT) tool for the development, design, and continuous optimization of API manufacturing processes. Continuous, in-line measurement of RI provides data and process insight that aids in understanding and designing different manufacturing steps. The data allows for the creation of process profiles that can be used for detecting deviations and ensuring process equivalence. The Vaisala refractometer provides trend data with the high reliability and reproducibility required in pharma manufacturing. Refractive index measurements are not affected by the presence of gas bubbles, solid particles, or color of the liquid. These features of refractive index make it ideal for many applications in the API manufacturing process.  

Refractive index is a fundamental physical property of liquids and is generally not dependent on the quantity of the sample measured. This simplifies scaling up processes from lab to pilot, and then to full scale production.  

Trend data is obtained in real time and can be compared to the design process profile obtained by RI, which determines process equivalence and aids in evaluating and determining other critical process parameters, tolerances, and optimal operating conditions. Furthermore, process profiles from RI data have aid in identifying problems during scale-up and for continuous optimization of existing processes. 

Optimizing solvent swap

Solvent swap, a common step in API production, aims to replace the original solvent from reaction, with a solvent more suitable for the next processing step. Solvent swap is typically done by distillation. During distillation, RI measurements are used to monitor top (post-condenser) and bottom product liquid concentrations, e.g., to ensure the correct concentration of API or solvent is obtained, to identify the right point for more solvent addition, and to reduce overall solvent consumption. During process development, RI can also be used to obtain important data for design such as vapor–liquid equilibrium (VLE) data. 

In-line measurements are also useful to identify problems in the process. For example, in one customer case, trend data from the Vaisala refractometer was used during process scale-up to establish process equivalence from two facilities (one in US and one in Europe) and the lab process profile. Thanks to the in-line data from the refractometer, this customer discovered that the US plant was not behaving as designed and required an additional swap step to achieve the same purity achieved in the design in the lab and the EU pilot facility. In this case, the RI trend data was an invaluable troubleshooting tool that helped ensure they could achieve optimal operating conditions in all facilities. 

By using refractive index measurements, our customer identified deviations from lab to pilot. They were then able to take immediate corrective actions, which led to savings in solvent consumption and increased product yield. The customer had used refractive index measurements from early stage in the laboratory in order to study the mixture, obtain VLE data and a process profile, and to design the swap process. Scaling up from lab to pilot was simplified by in-line refractive index measurements.

Refractive index measurements are a powerful PAT tool for the design, monitoring, and optimization of solvent swap processes, as well as a valuable trending tool for process insight and troubleshooting.  
 

Spray drying is a common sight in the manufacture of dairy products like whey protein concentrate (WPC) and lactose as well as in pharmaceutical manufacturing. The process creates dry powder from a liquid or slurry in a single step by quickly drying it using hot gas. Stable and accurate measurements of humidity, total solids (TS), and temperature, can help you make big savings in energy consumption and costs without compromising end-product quality.

Monitoring the right parameters is critical 

Spray drying is used in a variety of different industrial production processes to:
•    increase product shelf life
•    make products easier to handle during packaging, transportation, and storage
•    prevent microbial growth 
•    ensure product quality
•    save energy
•    increase yields

To optimize your spray drying process there are a few key process-critical parameters to keep an eye on: the soluble solid content of the feed to the dryer (typically measured in Brix or total solids (TS) and the inlet and outlet air humidity and temperature. 

Image: Accurate Relative humidity (RH), temperature (T) and the feed line Total solids (TS) measurements are critical for ensuring efficient spray drying

Spray drying monitoring using stable, reliable, and accurate measurement instruments will ensure that your product is dried sufficiently to avoid microbial growth – which is particularly important with food products – but not overdried, which can negatively impact product quality and result in excessive energy consumption and costs. With energy costs currently skyrocketing, ensuring efficiency is at the top of everyone’s agenda.

Optimizing processes with accurate Brix and TS measurements

Manufacturers can improve productivity by automating and optimizing their processes using in-line Brix and total solids (TS) measurement provided by the Vaisala K-PATENTS Sanitary Refractometer PR-43-AC. 

For example, in whey protein and lactose production – important food supplements that are commonly concentrated and preserved as powder – reliable, accurate in-line concentration measurement helps to control and adjust concentration levels after ultrafiltration and at
the evaporator inlet. Precise concentration measurement from the evaporator outlet helps to optimize energy consumption and ensures the correct feed product concentration to the spray dryer or crystallizer. 

In yeast production, where spray drying is used to dry the yeast extract to a fine powder or granulated particles, in-line concentration measurement can be used to control dilution of molasses at the initial stage, control fermentation progress, and measure the concentration of yeast extract to ensure the target dry solids level is achieved. 

Save energy and costs with accurate humidity and temperature measurement

As well as spray drying, humidity measurements are a key factor in optimizing a variety of other high temperature drying processes, including fluid bed drying and baking. When spray drying whey Vaisala’s humidity and temperature probes can be used to measure humidity and temperature in the dryer’s inlet and outlet air.

The inlet air humidity data is used to control the process, while the outlet air humidity data correlates with the moisture content of the powder. This means it can be used as an indicator of the final product quality. Finding the perfect balance saves time and energy by avoiding overdrying.

If you want to see for yourself how accurate humidity measurements can help you increase energy efficiency and improve quality and yields in your process, try our interactive drying simulator.