A Quarterly Newsletter of Parr Instrument Company | June 2017 | Vol. 4 No. 2
New Product Update
Corrosion Studies with Parr Reactors
Conference Feedback Survey
Probes, Sensors, and Glands Overview
Level Sensing within Parr Reactors
What’s New with Calorimeters and Related Combustion Equipment?
A Brief History of Catalyst Basket Reactors
Troubleshooting and Maintenance of Parr Calorimeters
Parr Team Member Focus
Welcome to ParrNotes
We thought we would use this edition of our newsletter to review the topics we covered at our Dealer Sales Training Conference we held in May in Oberursel, Germany. For those of you who were there, we want to thank you for making the commitment to be with us. Parr had representation from 30 different countries at the conference and I was thrilled to see that. I hope you found the meetings and the subsequent content of this letter useful in your business. If you want additional elaboration on any of these topics, please reach out to us and we will help you. You always have an open invitation to visit us in Moline for any training needs. I welcome your feedback on the conference or any other topic of business.
I often say our company has a family atmosphere to it and I would say our dealer network around the world is much the same. Besides the importance of the work we do, it’s nice to get together with old friends. We would not be able to build our global brand without you.
With warm regards,
President & Chief Operating Officer
Click on the underlined section titles below to download the associated PowerPoint Presentation. A complete packet of all resources listed in this newsletter may be downloaded from Parr’s Dealer Extranet here. You must log in with dealer access to view the files. Please contact us at email@example.com if you need assistance. –
Presented by Tim Lehman
Parr Instrument Company is pleased to provide marketing packets for each of our two new products: the 2500 Micro Batch System and the 4878 Automated Liquid Sampler. These packets include a one page marketing bulletin, a page from the price list (195M), and a quotation template. The 4878 marketing packet also includes a “for internal use only” explanation of the benefits and limitations of the device and an FAQ document.
During the dealer sales conference in Oberursel last month, Tim Lehman presented information about these two products, which included a comparison between the 2500 Micro Batch System and the MRS 5000, as well as a brief description of the mechanism of sampling employed by the 4878. You may download a copy of Tim’s presentation here, which includes the 2500MBS vs MRS5000 comparison, and obtain a copy of the operating instructions for the 4878 here, which includes a step-by-step description of the sampling sequence used by the 4878.
Presented by Dr. Joe Lambert
Over the recent years, it has come to our attention that many end-users are using our stirred reactors for the study of corrosion. Sometimes the goal is to learn if corrosion will occur. Sometimes the goal is to quantify the rate of corrosion to plan for equipment lifetimes and replacement schedules. At our Training session in Germany, Joe Lambert gave a presentation to discuss such studies.
The first topic covered was that acids are responsible for most corrosion. The amount of acid present becomes a significant variable in the evaluation. The concentration of acid present is measured with a pH probe. Examples were given of various commercially available probes and the temperature and pressure ranges over which they can be used.
Discussion followed about evaluating corrosion of a coupon placed in the solution of concern and then measuring the weight loss experienced by the coupon button. Parr can provide coupons whenever needed. Parr has also provided stationary or rotating coupon holders.
Discussion then moved on to recognizing that corrosion is a chemical reaction which means there is a flow of electrons = current and, therefore it can be studied with techniques developed for the field of Electrochemistry.
Examples were given of commercially available three probe systems (reference, counter, and working electrodes) as well as associated required monitoring Transmitters.
Finally the corrosion experienced in pipelines by moving fluids can be simulated by making the working electrode spin at a desired speed to mimic the boundary layers found in actual pipelines. Parr is currently developing a Rotating Cylinder Electrode (RCE) for this purpose and hopes to have it released for sale this year. Download the RCE sales brochure for additional information.
2017 Dealer Conference Feedback Survey
If you attended the Dealer Conference, please take this short survey to let us know how we did.
Presented by Tim Lehman
Over the years, Parr has been asked to provide a variety of sensors and probes for use in our stirred reactors and pressure vessels. At times, we have been asked to provide a complete system including a sensor/probe, while at other times we have been asked to provide only the means for inserting a sensor/probe supplied by the end user. In either case, it is critical that the desired device is specified by the customer: manufacturer and part number must be provided.
Examples of probes Parr has provided or provided accommodation for include:
- FTIR Probes
- Sonic horns/probes
- Liquid level sensors*
- Multi-point thermocouples
- pH/ORP probes
- Corrosion probes*
- Electrical and mechanical feed-through(s) using glands
*See below for more detailed information about the use of these devices.
Example illustrations of some of these probes may be found in this presentation.
Please contact Parr Technical Service for questions about how to accommodate your customers’ probes in a Parr reactor or pressure vessel.
Level Sensing within Parr Reactors
Presented by Dr. Joe Lambert & Tim Lehman
Many customers would like to know the amount of liquid present in their reactors. Although windows are one solution that can be offered, it is often the case that the end-user would like to have an event occur based on an electronic signal of the measured level of liquid in the vessel. This event might be the triggering of an alarm or perhaps the opening of a valve to let more liquid out of or into the vessel.
A presentation was given to discuss the physical limitations of commercial probes and why they are not amenable to our small laboratory reactors with limited head space and the need to avoid obstructing the magnetic drive.
Discussion continued on the various types of level control that can be offered by means of sensing with a multi-point thermocouple or using sonic sensors employing technologies from the realm of sound waves.
Also discussed were examples of other type of probes used for in-situ measurements of contents of the reactor, among them: a number of different types of FTIR sensors. Some examples of sonication probes used for the physical disruption of reactor contents were also discussed.
Presented by Dr. Jay Albert
The presentation given by Jay Albert at the 2017 Parr Dealer Conference in Oberursel, Germany focused on the new 6050 Calorimeter, several recent special purpose combustion vessels and calorimeter / combustion vessel safety.
The important features of the 6050 Calorimeter using the 1110 Combustion Vessel was offered along with a summary of the PC based user interface. The uses of the A1570DD4 Exhaust Adapter for the 1110 Vessel were described. The new 1109X High Pressure Micro Combustion Vessel was presented.
Custom combustion vessels for evaluating the performance of electric squibs (914429) and a test fixture for assessing fuel rich pyrotechnic starter compositions (916243) were discussed. These vessels are used for gathering pressure profiles during the combustion or reaction.
The design of a high pressure strand burner with optical windows for measuring the combustion rate of solid propellants was also shown.
The presentation concluded with two case studies related to calorimeter and combustion vessel safety. The first study emphasized the importance of properly tightening the 397A Compression Nut associated with the outlet valve on the 1108 and similar combustion vessels. Awareness of the anticipated energy release associated with the combustion of the analysis sample was mentioned. A case history illustrating the evaluation tactics of the failure of an older 1356 Calorimeter was reviewed. This calorimeter was routinely used to analyze industrial sewage sludge with samples having wide ranging compositions and combustion characteristics.
A Brief History of Catalyst Basket Reactors
Presented by Dr. Joe Lambert
The tubular reactor is by far the simplest reactor mechanically. It has no moving parts. Performing and understanding the kinetics in such a reactor present some challenges. One can only measure the concentration of reactants (Ci) before they enter the reactor inlet and the concentration of product species (Co) at the outlet of the reactor.
To evaluate the rate of reaction one must integrate the change in concentration over the length of the reactor.
Where Xi is inlet concentration, Xo is outlet concentration, R is reaction rate, W is weight of catalyst, and F is feed rate of reactants.
It should be noted that implicit in this discussion is indication that one does not know where in the reactor the reaction took place or how much catalyst was actually required to achieve the measured level of conversion.
One way to accomplish this is to run the reaction under ideal conditions of a Plug Flow Reactor (PFR) in which complete radial mixing and zero axial mixing is achieved. One can then shorten the catalyst bed. In the limit that the bed becomes infinitely small, one is assured of exactly where the reaction took place:
Now the difficulty becomes that with a bed so small, very little reaction takes place and it becomes increasingly difficult to measure the change in conversion (Ci and Co). To overcome this problem, one can imagine recycling some of the product to the inlet.
This idea implies that if we put a series of completely mixed, stirred reactors in series, we can achieve essentially a tubular plug flow reactor.
To achieve such a completely mixed, stirred reactor, Josef Berty, while working with Union Carbide back in the 1970’s, created an internal recycle reactor that has become known as a Berty Reactor and became the first of many reactors sold by Autoclave Engineers. This reactor featured a spinning impeller that forced gas up the internal side walls of the reactor and forced it down through a central packed bed of catalyst to then repeat that path to achieve complete mixing and full recycle.
This impeller, however, was not powerful enough to push liquids along a similar path and as the era of coal liquefaction arrived, a new type of reactor was needed to perform Three-phase (gas/liquid/solid) reactions.
The first of these reactors came from the laboratory of Prof. James Carberry at the University of Notre Dame. In this reactor, catalyst was packed into four lobes of an internally-stirred “cruciform” basket.
Although highly recognized for its innovative approach of moving the catalyst through the fluid, as opposed to moving the fluids through the catalyst, this reactor had an issue because particles located furthest from center traveled much faster than those near the center. This created different hydrodynamics of flow on different catalyst particles.
To overcome this problem, John Mahoney at Amoco Oil Company, recognized that it would be good to just pack the outer edge of each lobe. But as this would significantly reduce the amount of catalyst, the end result was to pack the catalyst in an annular basket.
This gives rise to what has become known as the Mahoney Spinning Basket reactor. One of the difficulties found with this style of agitation was that when operated in more viscous fluids, each catalyst particle sits in the wake of the particle in front of it.
This issue was resolved by a colleague at Amoco, Dr. Ken Robinson. Ken’s approach was to return to the concept of passing the fluid through the catalyst but retaining the annular packed bed of catalyst.
Although spinning basket reactors are mechanically more complicated, the mathematics of the recycle (gradientless, or CSTR) is that the rate equations now involve a simpler subtraction of concentrations, rather than a mathematical integration.
W/F = (Co-Ci) / R
This “Robinson- Mahoney” reactor featured a multi-bladed impeller in the center intended to throw liquids through the catalyst bed. It was later noticed that this impeller did not move fluids through the top, center, and bottom of the bed at the same velocities. An improvement patent (US# 4,594,228) was issued to Joseph Lambert (Joe) of Standard Oil of Ohio (SOHIO) on June 10, 1986. The improved impeller added pitched blades to the top and bottom of the original impeller to provide improved recycle and a more consistent flow.
Still not totally happy with the performance, Joe went back to the drawing boards upon his arrival at Parr Instrument Company and did some further improvements. To achieve uniform flow from the top to the bottom of the catalyst bed, it was assumed that a bed packed with white candies having a red outer coating to simulate catalyst particles should all turn a white color when subjected to a water flow created by the ideal impeller. The end-result was the current version of what Parr calls the “Static Basket”. Note the uniquely shaped impeller:
This Static Basket design is recommended for liquid/solid and gas/liquid/solid reactions. It is available in a version with a 50 cc catalyst bed for use in Mini-Series reactors and also in a version with a 150 cc bed for the 1- and 2-Liter reactors. The Parr Dynamic Basket is the more common choice for gas/solid reactions. It is available in a version with a 150 cc bed for use in our 1- and 2-Liter reactors. This spinning basket reactor features improved baffling to avoid wake issues.
Presented by Dr. Andrei Yermalayeu
Even a simple problem of misfire can be caused by various underlying problems: wet cotton thread, issues with the stirrer, lead wire continuity, difficultly igniting the sample, other hardware or experimental issues. It is impossible to provide a troubleshooting flowchart for each situation. Thus a more fruitful approach is to define the ideal experiment, and try to understand what went wrong. The list of necessary conditions for a successful experiment is rather brief.
First, there must be a thermal balance within the calorimeter, and between the calorimeter and its surroundings. This must happen in order for the calculations based on a theoretical calorimeter model to be valid. Essentially, the stirrer must mix the water in the calorimeter uniformly, the jacket temperature must be stable, and there should be no significant energy flow in the surroundings, i.e. direct sunlight or air conditioning vent exhaust. Second, the calorimeter and the vessel must be in good shape, no water or gas leaks, and no corrosion present. The vessel must be loaded correctly and filled with oxygen. Third, the temperature measurement must be free of flaws. Fourth, the sample must be burnable, and if possible in a repeatable manner.
Whenever a problem occurs it is important to understand whether this problem originates from the sample or the calorimeter. It is pretty straightforward to tell: if the problem does not occur while using benzoic acid, then this is a sample issue and should be resolved by correct sample preparation.
If it is determined that there is an issue with the calorimeter, it is important to remember that the majority (> 90%) of issues in the field are solved by doing routine maintenance.
Essentially any problem with the calorimeter should be viewed from the standpoint to determine which of the necessary conditions for the experiment was violated. For example the pre-period and post-period timeouts are the consequence of the violation of the first necessary condition – the thermal balance. Underlying problems in this case are usually stirrer failure, jacket temperature regulation issues, water leaks, or solenoid malfunction.
In any case, if you experience a problem with a Parr product, give us a call or send an email, we are always ready to help.
Maintenance and Safety
Regular maintenance is important not only to get good results and avoid technical issues, but it is also crucial for safety. An oxygen combustion vessel normally contains 30 bars of highly reactive pure oxygen. However not many users realize that during the ignition the internal pressure builds up in a matter of seconds, and depending on the rate of burning, the peak pressure may be multiple times higher than the initial filling pressure. That’s why it is especially important to avoid explosions in oxygen combustion vessels not designed to handle it. During this pressure rise the sealing is subjected to significant stress during this short time frame, and if there is any problem, it can lead to a burn through with hot gases, destroying the vessel and surroundings.
Each oxygen combustion vessel has a maximum working pressure limit. Because it is not possible in the majority of the cases for the user to tell the burning rate characteristics of the sample, it is common practice to set forth an energy limit for each oxygen combustion vessel type. This value can be found in the supporting documentation to the calorimeter. Overshooting this value compromises the vessel integrity, subjecting the user to unnecessary danger.
Parr guarantees that the user receives a safe product. There are multiple manufacturing and testing steps that ensure that our product meets or exceeds the requirements. First, Parr oxygen combustion vessels are designed with safety in mind and according to the regulatory guidelines. Then the production starts with material tensile testing. Specimens of a received material, taken from determined locations, are stretched until torn to determine the strength of the material. If the measured parameters are less than required the material is rejected.
Each built oxygen combustion vessel is subjected afterwards to a hydrostatic test with a pressure of approximately 1.5 times higher than the maximal working pressure, and inspected dimensionally. If passed it is further subjected to combustion of twice the normal amount of benzoic acid under elevated oxygen pressure, observed for any gas leaks, and again inspected dimensionally. In both those tests, metal must show no permanent deformation, otherwise the vessel is rejected.
It is a Parr duty to deliver a safe vessel, but it is the user’s duty to support this safety by performing necessary maintenance throughout the product life. There are two main components that can compromise the vessel’s safety. First, is the wear and tear of the O-rings. As it was mentioned above any gas leak can turn the vessel into a fire breathing pit during the ignition phase. Thus damaged O-rings may seal at 30 bars, but fail when the pressure peaks. Hence it is essential to inspect regularly the condition of the O-rings. At any presence of decay, or damage, they must be replaced. 500 firing maintenance is meant to refresh O-rings, and it must be done after 500 firings, 6 months, or any observed degradation, whichever comes first.
Another component that may compromise the integrity of the vessel is corrosion. Whereas corroded electrodes can produce misfires, corroded sealing surfaces and walls compromise the sealing and metal strength. It is crucial to perform 5000 firing maintenance by sending a vessel back to Parr for inspection. During this procedure Parr not only reconditions the vessel but also performs hydrostatic and leak tests in order to determine whether the vessel is still safe to use.
Pictures from the Sales Conference
It was great to share ideas and time with our colleagues and friends who were able to make it to Oberursel. Click on the gallery below to see pictures from the event.
Parr Team Member Focus
Tony Dietzel, Technical Sales Representative
Tony holds a Bachelors of Business Administration degree from the University of Wisconsin – Whitewater where he also minored in economics and chemistry. After college, Tony lived in South Dakota until he relocated to the Quad Cities in 2010 to join Parr’s Sales Department. As one of Parr’s technical sales representatives, Tony provides customer service and technical support to customers and representatives both domestically and abroad. While Tony enjoys many aspects of his job he says what he likes most is that it allows him to interact with very intelligent people who have research and equipment design needs that are always changing. Tony is glad that he is able “to have a hand in helping our customers design custom systems that may help solve some of the world’s challenges.”
Originally from Kieler, Wisconsin, Tony now resides in Davenport with his wife Amy and their daughter Ellie who will be turning two later this month. Tony and Amy are expecting their second child in late July. Outside of work, Tony spends his time with his family, playing basketball, biking, and working on home improvement projects. Despite his busy schedule, Tony is an avid sports fan and makes time to support two of his favorite home state teams: the Green Bay Packers and Wisconsin Badgers.
Tony’s knowledge of Parr products, dedication, and friendly personality make him a very valuable asset to the Parr Team.
254th ACS Fall National Meeting and Exposition
August 20-24, 2017
Please visit us at Booth #2001
August 27-31, 2017
Look for our representatives from Parr Instrument Company GmbH & USA
September 3-7, 2017
Prague, Czech Republic
Look for our representatives from Parr Instrument Company GmbH
View our complete 2017 Trade Show schedule.