Offices in ENGLAND, USA, CHINA, INDIA Representation Worldwide
Process Safetyand & Optimisation Calorimetry Battery Safety Battery Performance Studies
Welcome to THT’s latest newsletter! As well as updates from our international offices, we are pleased to include a selection of latest developments and application notes from our test laboratory.
India In India, demand for the RSD Rapid Screening Device is strong. Since the last eNewletter, our representatives KAN-THT have sold six new systems to academic and pharmaceutical laboratories across India.
China Earlier in the month, Danny Montgomery visited the Nanjing University of Science and Technology. NUST have a large safety lab with many calorimeters including a THT ARC, RSD and uRC. Danny gave a talk on the application of THT instruments to process safety at a process safety conference hosted by Professor Chen. Two days of training on THT was carried out at the NUST process safety lab. We welcome Mr. Hengwei Liu to our China Office as Battery Applications Specialist. Previously Hengwei was a THT ARC user at Tsinghua University, Beijing. 2
In response to the increased demand Mr Rao Mallikharjaun has joined the sales team as South Regional Manager. KAN-THT will be exhibiting at P-MEC / CPhI Mumbai, India. 2-4 December. Booth number O32 UK Ben Watson joins THT to continue our success in providing innovative instruments and software to gain quantitative heat and pressure data from the widest range of reactive chemicals and materials. Ben joins as as Electronics and Manufacturing Production Team Manager and comes with a wealth of experience within the Industry. We welcome Ben’s appointment and are confident he will play a key role in providing and implementing high quality solutions for our clients.
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ARC Detection of Exothermic Reactions: Onset and Sensitivity The ARC combines the best of both, but has limitations. With step heating onset is determined after multiple isothermal periods, sensitivity is ‘high’ due to the large sample mass; heat release is quantified by extent of temperature rise. However the features are combined to give technology that replicates potential runaway reaction safely in a lab. High sensitivity is not a major feature; classic ARC tests are carried out overnight and in this time period quality temperature and pressure data that mimics a runaway reaction in real life is obtained. Onset is classically determined when the temperature rise rate measured in the ARC is greater than 0.02°C/min. From onset, the rate increases as the temperature rises. Typically if
a lower rate (eg 0.005°C/min) is selected as the criterion for onset, not much more information may be obtained but the test would take a much longer time (perhaps an additional 24 hours). However, there are times (eg onset of explosive materials, evaluation of additives, quantifying minor low temperature impurity reactions) when detection at low heat release rate is useful. Onset at 0.005°C/min can easily be accomplished, but the THT esARC system can be used to determine and quantify heat release at rates of 0.002°C/min and even 0.001°C/min. This has been achieved by improved control algorithms and makes the THT ARC system unique and has higher sensitivity than other commercial adiabatic calorimeters. The data below illustrates THT esARC calorimeter stability and onset detection.
In the data shown, an esARC was calibrated at 0.005°C/min and this was followed by a drift check; all rates were below 0.005°C/min and, as illustrated, where most challenging (higher temperatures) the rate is typically near 0.001°C/min. Onset is seen in the graphs where detection at 0.002°C/min is simply achieved. Such performance has never been published by any competitor calorimeter, and it is suggested the stability of the esARC allows it to have a level of detection which provides 10 to 50 times greater sensitivity. Contact THT for full details of the performance of the esARC system in sensitivity and other aspects. 3
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RSD
µRC Solid Addition Accurate measurements of the enthalpy of dissolution of solid compounds is an area of increasing interest. In response, THT has made a major improvement to the design of the solid addition accessory. During development we found that immersing the tube in water is not necessary for isothermal equilibrium – and suffers from issues such as possible water ingress and potential of interference of the stirrer. The new solid addition accessory consists of Stainless Steel Sample Delivery Tube (5mm ID, 30mm length); Modified PTFE & Stainless Steel Shunt; Reusable Teflon plug; Teflon Plunger; Standard Glass Vial and Standard Vial Lid. Vial Delivery Tube
PTFE Shunt/Cap
Vial Lid
Teflon Plug
Stainless Steel Shunt
Teflon Plunger
New Applications: Quality Control / Rapid Screening Rapid screening and quality control are at the heart of key applications for the RSD. This is because the RSD has the ability to measure up to 6 sample simultaneously, to carry out a test in 1 hour. Application 1: Highest Sensitivity Waste streams; recycling of solvents. Solvent recovery, waste recycling… important aspects of Eco-friendliness as well as economy. Consider a solvent to be distilled for re-use. In a pharmaceutical manufacturing process the solvent may carry over 1-2% of a reactive ingredient. How much? Determining a small quantity presents challenges to most calorimeters as the 98-99% solvent acts to absorb heat in any analysis. Rapid RSD scanning is the answer. See the real raw RSD data below with 3 samples of DTBP in toluene at 1%, 2% and 3% level.
The design allows for up to 400mg of powder to be manually added to the µRC sample vial. More details are given in our Technical Applications Note. The uRC brochure can also be viewed in full online. Hydrogenation Many chemical processes, particularly in industry, require substrates which exist in the gas phase under typical reaction conditions. Furthermore, the transformations discovered in recent years are almost ubiquitous in requiring catalysts. While many novel systems are homogeneus, a solid support will promote high turnover numbers and improved recyclability. Results from 1% (top) 2% (middle) and 3% (bottom)
for exploring kinetics and determining the reaction enthalpies of these processes. In our most recent Technical Applications Note the hydrogenation enthalpy of Octene to Octane has been studied at ambient pressure with a palladium catalyst.
Request THT RSD Technical Application Notes
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October 2014 Newsletter
Application 2: Resins Quality control of resins is of importance firstly to fully characterise the recipe and then to determine batch variations Curing prior to release from the reactor can lead to a solid and a large cost! To develop new formulations, understanding the amount of additives, many tests are likely to be required and these carried out under isothermal conditions. The key parameter to determine is onset temperature and time prior to exothermic reaction; an induction time. Because tests could take hours or even days the use of multiple samples per test is of great value. The results shown below for a test with three samples and the data is imported into ARCCal for convenience and to extend the analysis ability (for example to determine time to full curing). Repeatability is shown in the table. Temperature as a Function of Time
250 200 Heat (J/g)
RSD
rates. Firstly by the ‘classical’ method of measuring peak area and by use of a calibration derived from a prior test with a known heat release to scale the heat axis. Secondly by theoretical calculation based upon knowledge of heat exchange and heat transfer and model development.
1 150
2 3
100
4 50 0 5% DTBP
10% DTBP
15% DTBP
Four tests with 5%, 10% and 15% DTBP. Method used: calibration with 10% DTBP Standard Sample (triplicate prior test). Calibration constant = 7.2. And below tests at differing heat rate.
250
Temperature as a Function of Time
Heat (J/g)
200 2.5°C/min
150
4°C/min
100
6°C/min
50 0 5% DTBP
10% DTBP
15% DTBP
Predicted Time to Max Rate
Temp °C
Time 1 (min)
Time 2 (min)
Time 3 (min)
70
600
550
565
80
30
310
325
90
180
190
205
100
120
130
145
120
45
45
60
Improved Software: Thermokinetic Analysis The RSD is designed as a screening tool but, with good thermal control and heat measurement, the RSD allows repeatability of data and the ability to measure heat of reaction. Any calorimeter similar to the RSD (multipurpose, thermal ramping, large sample, lower cost) is not designed for quality quantitative measurements. However measurement of Heat of Reaction is possible to a reliability of 5-10% within a range of heat release amounts and
The data above show a series of RSD tests, repeated at differing heat release values and at differing ramp rates. A prior calibration constant was used. Heat releases for 5%, 10% and 15% peroxide are near 60 J/g, 120 J/g and 180 J/g. In house testing has shown that the method is most reliable when the total heat release is 100-1000J, released on a time period of 0.5 - 15 minutes. Best results are obtained when calibration is done with a sample where the known heat release is similar to that being measured. Nevertheless the new RSD software enhances the quantitative nature of the RSD.
Š Thermal Hazard Technology 2014 All rights reserved.
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Offices in ENGLAND, USA, CHINA, INDIA Representation Worldwide