Measuring oil contamination in anhydrous ammonia can now be done quickly and accurately without the use of hazardous chemicals like hexane. OSS has developed a measurement system for oil contamination that allows small sample sizes and accurate results in minutes, saving your company time, money, and increasing safety for your employees. This green technology can be used in many applications, but this presentation demonstrates its use in ammonia as presented to the International Fertilizer Association, IFA.
As a new associate member of the International Fertilizer Association and on behalf of Orono Spectral Solutions, I want to thank the association for the opportunity to present this paper on a new method to measure oil in ammonia. We believe that the summit’s theme of "SHE Excellence: - A Foundation for Fertilizer Production" applies to the new test method. Originally CF Industries was scheduled to present a paper on this technology but due to a US Government Travel Warning and their internal policies they had to decline the opportunity.
When OSS joined IFA in January, we were pleased to see that this Technology summit had a theme of Safety, Health and Environment. The technology which I am about to describe addresses all three legs by the reduction in the amount of ammonia needed for testing and the elimination of the use and the need for disposal of Hexane.
As a brief history, OSS is a spin-off from the Laboratory for Surface Science and Technology at the University of Maine. The laboratory and thus the company, is focused on developing solid state surface technology that enables rapid, safe and accurate detection of unknowns and/or quantities of known materials. The application of the technologies include identifying unknown liquids or powders in shipping containers, boxes or packages.
The Tibbets Award is given by the US Department of Defense to honor small firms that exemplify notable lifetime achievement in innovation research. OSS received it in 2013. In 2016 the oil in ammonia technology was the basis for CF Industries’ Stephen R. Wilson corporate safety award winner. And this year the company’s technology has been nominated for the 2017 US EPA Presidential Green Chemistry Challenge Award.
The original objective of the technology was to measure oil in water. In particular, to dramatically reduce the time needed for an answer; to eliminate the need for a known hazardous, flammable, neurotoxin – Hexane; to simplify the procedure and to improve the safety for the technicians operating the tests. The cost savings is from the fast feedback and control for management and process engineers.
Once developed, one of the first and very unexpected uses of the technology was in measuring the oil concentration in the gulf of Mexico as a result of the British Petroleum Deep Water Horizon oil spill in 2010. Samples of surface water, subsurface water and sediment were taken and the technology provided immediate answers to where the oil was located and the concentration of oil at various points around the gulf. The technology has also been used to measure oil concentrations in the Canadian Alberta Tar Sands and waste water oil and grease content in factories around the world.
Measuring oil in ammonia is not a regulatory requirement but it is measured to ensure that product quality is within acceptable commercial performance requirements and that the manufacturing plant operation continues as originally designed. For agricultural application, excessive levels of oil in ammonia can lead to fouling “blocking” of application nozzles causing uneven distribution of nitrogen in the fields. For operations personnel the objective is to determine whether there are oil leaks into the product and then as quickly as possible eliminating the source of the problem before significant quantities of substandard ammonia is produced. CF Industries was looking for a system that would provide accurate results while eliminating many of the challenges of the current oil in ammonia measurement process.
The current process requires a significant amount of glassware, dangerous chemicals, hotplate and significant preparation all while under a laboratory air hood.
Hazmat logistics in use and disposal of chemicals. Is also required.
An overview of the current method is shown on this slide.
Collect 500 to 2,000 mls of ammonia (using large volumetric glassware) The issue here is transporting a large amount of ammonia from the sampling location to the laboratory. The ammonia is then allowed to evaporate. This is conducted in a controlled environment e.g., chemical fume hood, due to the known hazards associated with ammonia handling; After the ammonia has evaporated, the non-volatile contaminants are left behind and form a residue in the flask Approx 200 mL of hexane is then added to flask to re-suspend the residue, and this residue+hexane mixture is then transferred to a weighing pan This solution is heated and after the hexane evaporates, the remaining residue is weighed using a microbalance to finally determine the concentration of oil contamination in the original ammonia sample. However, what is left behind may not only be oil. Other contaminants, such as rust or other materials present in the system can be left and included in the weight of residual components. In all, the test takes over 8 hours, including 3 hours of technician time for one test.
Issues with the current process include - Sample size is 500 to 2,000 mls, depending on the current process and number of tests to be run. - The process is complex and lengthy - Hexane is a flammable solvent, a known neurotoxin, costly and difficult to dispose as it is classified as a regulated agent in both the US clean air and clear water act. Health Hazard – 1 Slightly Hazardous Fire Hazard – 3 Below 100 F (38 C)] Instablity – 0 Stable
1. The main components of the process are shown on this slide. 2. An extractor, a syringe and wand, a Fourier Transform Infrared Spectroscopy, FTIR, unit 3. Desk top computer
The new process is shown on this slide 1. Collect a small sample – 50 mls is more than enough 2. Extracting a sample means taking a syringe and extracting 10 mls of sample and pushing it through an extractor 3. The extractor is then placed into an FTIR Beam for analysis. Within a few minutes the process is complete with a permanent picture of the specific scan from the sample. 4. In approximately 20 minutes there is an accurate determination of oil content in ammonia in triplicate. The three samples can be retained for further analysis and quality confirmation.
Fourier Transform Infrared Spectroscopy (FTIR) is a technique which is used to obtain an infrared spectrum of absorption or emission of a solid, liquid or gas. An FTIR spectrometer simultaneously collects high spectral resolution data over a wide spectral range. The first low cost spectrophotometer was produced in 1957 but due to the complex calculations required to get meaningful data, only became practicable with the advent of mini-computers in 1965.
So how does this work? Maybe we could think of it in this way. Assume that the incoming beam has the colors of the rainbow. Depending on the material on the membrane, some colors will pass through and others will be absorbed. The specific light colors that are absorbed identifies the material in the membrane. How much light color is absorbed defines the quantity.
The quantitative determination is possible, due to something called the Beer-Lambert law. Double the concentration, and you double the absorption, etc. This is a simple but very effective method of quantitative analysis when we have well-defined peaks due to components of interest.
From this chart, the absorbance band at 2920 corresponds to the anti-symmetric CH2 stretch vibrational mode in oil, where the peak height corresponds to the concentration of oil. The other peak at 2850 is also associated with a different CH2 vibrational mode, symmetric CH2 stretch, of the same molecule. 2920 is more commonly used since it is the dominant peak in the spectrum. So for measuring oil in ammonia, we know that oil has an absorbance level at 2920. Using the height of the peak at that absorbance vs. a standard, the amount of oil can be calculated. It should also be noted that the peak at 2920 is only measuring oil content. There is no interference from other contaminants that may be present in the ammonia. These calculations are done automatically by the software programs designed specifically for the material being tested, in this case, ammonia. The specific spectra from a collected sample can be saved and compared vs. other samples and can be saved for future reference.
So the process is to obtain a minimum size sample to run a test in triplicate using 10 mls per sample. The 10 mls of sample are pushed through an extractor with the solid state membrane. The membrane is then placed into the beam of the FTIR unit and a result is presented within a minute. The process can be repeated as frequently as desired. Permanent records exist both from the scan chart which is permanently stored within electronic filing system. It is also a permanent record from the actual retained sample. It can be retested and will provide the same result for up to a year. Currently DEF samples are saved for several months for that quality purpose alone. So the test is simple, what about the results and accuracy?
This chart illustrates the accuracy of the technology in determining oil in ammonia. In this particular instance, Mineral Oil was used as the spiking ingredient. The offset at “0” is due to the fact that the ammonia already had some residual oil contamination in it. As the chart shows, ammonia was spiked with two levels of mineral oil, 6 ppm and 14 ppm. The resulting R squared calculation is almost one indicating that there is nearly perfect correlation from the data. It would also be worth mentioning that there are solid state standards that are used to calibrate the FTIR instrument for operation.
This slide summarizes the advantages of the technology vs. the current method. These advantages are the ones found in the laboratory. What this comparative lists do not show is the advantages for the operations people and the site in general. A 20 minutes vs. an 8 hour minimum turn around time means that issues can be identified much more quickly, actions to repair problems can be confirmed more rapidly and this all leads to less material that is outside of specification. Thus a significant financial benefit in terms of a reduction in reworked material or material on product quality hold.
Although the presentation today has focused on the measurement of oil in ammonia, the technology is fully applicable to the systems listed on this slide. Any fluid system not listed can be investigated to determine the applicability of the technology. I would like to highlight one area of development and that is the water in ammonia test method.
A new and similar test method to the oil in ammonia method is currently under review by the US Department of Transportation. The advantages here are speed, accuracy and safety.
To summarize, a new oil in ammonia test method has been developed and is being used by large ammonia manufacturers. The technology impacts safety, health and environment matters and also has a significant financial benefit to the customer.
Finally, I would like to mention that in the time that I have presented this paper today, the laboratory technician would have completed his or her 3 oil in ammonia tests.
Measuring Oil in Ammonia - OSS ClearShot Technology
Orono Spectral Solutions, USA
Safely, Quickly and
Oil in Ammonia
Summit Theme - SHE
• Safety – reducing exposure to ammonia
• Health – eliminating the use of a known
extremely flammable, neurotoxin, n-Hexane.
• Environment – no longer need to dispose of
Technology addresses all three areas of SHE principles
Orono Spectral Solutions
• Spinoff of University of Maine (US) Laboratory
for Surface Science and Technology
• Awarded 14 government projects ($8.6 M)
• 2013 Tibbets Award & 2016 CF Safety Award
Leading edge solid state surface technology driven organization
Genesis of the Technology
• Using solid state technology developed to test in
any fluid system
• Objectives - Speed, accuracy, safety and cost
– Gulf of Mexico - Deep Water Horizon (BP) spill
– Alberta Tar Sands – oil concentration
Initial focus - a radical improvement to measuring oil in water
Measuring oil in Ammonia
• CF Industries looking for solutions to
– Safely test oil contamination in ammonia
– Quickly identify process control issues
– Reduce corporate risk
Request from a leading ammonia manufacturer led to application
Materials Required to Measure
Glassware, hot plate and dangerous chemicals
Oil Determination – Process
Mass corresponds to
Test Time: 8+ hours Tech Time: 3+ hours
Current method is long, complex, dangerous and costly
• Large sample size
• Safety risk: carrying sample through the plant
• Solvent (n-Hexane) & acid use
• Complex process
• Time consuming
• One “shot”
Issues with the Current Process
Several factors with current method are driving development
Materials Required to Measure
No glassware, no chemicals, no heating
New Process Summary
Extract Sample Place in FTIR
Time: < 20 minutes
3050 3000 2950 2900 2850 2800 2750
Absorbance / Wavenumber (cm-1) Paged X-Zoom CURSOR
File # 1 : BASELINE 11/5/2007 6:47 PM Res=8
disk 1 background after 10 ml ~30ppm oil in water
Simple, quick, accurate and less costly process address SHE
A =- log10 = e l c
A = absorbance
e = absorptivity
c = concentration
Infrared technology enables precise quantitative measurement
Oil in Ammonia Output
Oil absorbance at 2920 and height relates to concentration
3050 3000 2950 2900 2850 2800 2750
• Sample 10 mls for each test - triplicate
• Place the extractor into the FTIR beam
• Program provides operator with a ppm oil level
• Permanent record of the results
Summary of New Process
Simple, accurate, safe and creates a permanent record
Measurement of Known Amount
Spiking amount of mineral oil and measuring using technology
Method Performance Summary Data
Method Detection Limit 0.2 mg/L (ppm)
Detection Range 0.2 – 20 mg/L (ppm)
Precision at 3.5 mg/L 12%
Benefits of the New Process
Proven overwhelming advantages of new technology
• Fragile Glassware
• 500+ mL Ammonia (1 sample)
• Boiling Water, Hot Plate
• Hexane, Hydrochloric Acid
• 1-Day Turnaround Time
• 3 Hours for Lab Technician
• Hazardous Waste
• Operating Cost
• No Glassware
• 30 mL Ammonia (3 samples)
• No Heat Source Required
• No Additional Chemicals
• 20-Minute Turnaround Time
• 20 Minutes for Lab Technician
• Recyclable, Reusable Filters
• EPA Green Chemistry
• Operating Cost 25 – 30% less
Old Method New Method
• Oil in Water, UAN, Urea and Air
• Development options
– Water in ammonia 0.2 to 0.5%
– Low water content < 30 ppm
• Development for oil and gas industry
Additional testing options for the technology
Sound science and proven SHE advantages
• Safety – Significantly improve safety
• Health – Eliminate hazardous chemical use
• Environmental – No hazardous waste
• Financial Impact – At lower operating cost and
improves corporate sustainability