Presentation on theme: "Adventures in ‘Real World’ Chemistry David M. Manuta, Ph.D., FAIC, President, Manuta Chemical Consulting, Inc. Waverly, OH 45690-1208 November 11, 2002."— Presentation transcript:
Adventures in ‘Real World’ Chemistry David M. Manuta, Ph.D., FAIC, President, Manuta Chemical Consulting, Inc. Waverly, OH 45690-1208 November 11, 2002 at SUNY Binghamton
Mission Statement: The Application of Fundamental Chemical Principles to Solve Problems. Vision Statement: To Solve Problems That Aren’t in Any Book. Business Objective: Have I Applied My Specialized Knowledge to Help Others Who Under Other Circumstances Wouldn’t Be Able to Help Themselves?
Manuta Chemical Consulting, Inc. (MC 2 ) has been involved in many interesting scientific investigations. Among these investigations are: Chemistry Issues in the Uranium Enrichment Process Participating in the Shut Down of a Manufacturing Plant in Nevada Unusual Chemical Reactions in an Aluminum Fire
Typical investigations require the client to allow a “site visit.” In addition, the advent of the Internet enables the investigator to bring “the Library” home. Some valuable reference volumes are: CRC Handbook of Chemistry and Physics Chemical Engineering for Chemists by Griskey College Physics by Serway and Faughn General Chemistry by Brady Organic Chemistry by Solomons Physical Science by Shipman, Adams, and Wilson
Some Chemical Reactions in Uranium Enrichment UF 6 (g) + 2 H 2 O(g) UO 2 F 2 (s) + 4 HF(g) (1) UF 6 is uranium hexafluoride, an easily sublimed solid, and UO 2 F 2 is uranyl fluoride, a high melting point solid. The designations (g) and (s) are for gas and solid, respectively.
UO 2 F 2 (s) + 2 ClF 3 (g) UF 6 (g) + ClF(g) + ClO 2 F(g) (2) ClF 3 is chlorine trifluoride, ClF is chlorine monofluoride and ClO 2 F is chloryl fluoride. This disproportionation reaction is used to recover uranium hexafluoride from solid uranium deposits, primarily as uranyl fluoride, from the process piping.
Fluorine chemistry is important in uranium enrichment and in the recovery of uranium hexafluoride. In-leakage of water vapor into the below atmospheric pressure uranium enrichment gaseous diffusion cascades is responsible for the chemical reaction producing uranyl fluoride and hydrogen fluoride. The thermodynamics pertaining to hydrogen fluoride formation are favorable in uranium enrichment gaseous diffusion cascades.
When the ratio of water to uranium hexafluoride is less than 2:1, other intermediate uranium oxofluoride compounds (U-O-F) are formed. This work was presented in two papers at the A.C.S. National Meeting in Chicago, IL in 1995. Hydrogen fluoride is considered to be ubiquitous in gaseous diffusion cascades and an infrared method has been devised to detect and quantify it. This work was presented in a paper at the A.C.S. National Meeting in San Francisco, CA in 1997.
Shutting a Plant Down in Nevada Advanced Specialty Gas (ASG) facility in Dayton, NV was a manufacturer of nitrogen trifluoride (NF 3 ). This gas has been used as a rocket propellant and has an application in the manufacture of circuit boards. With the phase out of sulfur hexafluoride (SF 6 ), due to greenhouse gas and global warming issues, the demand for NF 3 has grown in recent years.
ASG obtained a special use permit from the Lyon County (NV) Board of Commissioners to manufacture NF 3. The special use permit enabled ASG to keep ammonia (NH 3 ) and hydrogen fluoride (HF) on site. The balanced chemical reaction to produce NF 3 is: NH 3 (g) + 3 HF(g) NF 3 (g) + 3 H 2 (g) (3) The special use permit indicated the amounts of NH 3 and HF that Lyon County would allow ASG to store on-site.
In my investigation, among other findings: I was surprised to learn that ASG was allowed to keep more NH 3 on-site than HF. The HF became the limiting reagent in the NF 3 manufacturing process. I was also surprised to learn that the H 2 was vented out a smoke stack. No attempt, to the best of my knowledge, was made to recover it.
ASG had three releases to the environment and one explosion which blew the roof off of their lab between 1997 and 2000. The explosion also started a brush fire in the immediate area of the plant. It was after the explosion and brush fire that my expert services were requested. The owner of the real estate contiguous to the plant recognized that he would be unable to sub-divide his land for residential housing as long as the ASG plant continued to operate in Dayton, NV. I was retained, primarily, to protect this man’s investment.
Lyon County had previously hired experts who did not have experience in fluorine chemistry. As a result, little progress had been made regarding ASG. I testified before the Lyon County commissioners in their chambers and I was specific in identifying the unsafe practices at the facility. The Lyon County commissioners one week later voted 3-2 to revoke ASG’s special use permit. This action effectively shut the ASG facility down. Copies of my technical report plus articles from the Carson City and Reno newspapers are available.
The Chemistry of an Industrial Aluminum Fire In December 1998, there was a fire at the Portsmouth Gaseous Diffusion Plant in Piketon, OH. I was tasked by senior plant management to determine the cause and origin of the fire. I also was tasked with supervising the on-site laboratory studies of gaseous and solid samples brought out of the damaged process equipment.
Unusual chemical reactions in the fire 2 Al(s) + 3 UF 6 (g) 2 AlF 3 (s) + 3 UF 4 (s) (4) AlF 3 is aluminum fluoride UF 4 is uranium tetrafluoride 2 Al(s) + 6 HF(g) 2 AlF 3 (s) + 3 H 2 (g) (5) These two reactions apparently started the fire. Rotating equipment made out of aluminum started to melt and the molten aluminum then reacted with the available fluorine-bearing compounds to produce aluminum fluoride and considerable amounts of heat.
2 Al(s) + 3 UO 2 F 2 (s) 2 AlF 3 (s) + 3 UO 2 (s) (6) 14 Al(s) + 3 C 2 F 4 Cl 2 (g) 4 AlF 3 (s) + Al 2 Cl 6 (g) + 2 Al 4 C 3 (s) (7) Additional chemical reactions producing aluminum fluoride took place, culminating in the catastrophic loss of coolant (R-114 is C 2 F 4 Cl 2 ). The coolant was actually consumed in the fire. Al 2 Cl 6 is aluminum chloride Al 4 C 3 is aluminum carbide.
The series of chemical reactions producing aluminum fluoride effectively created the “fluorine-analog” of the Thermite reaction. In order to generate aluminum carbide, temperatures in excess of 2000°C (3632°F) in a hydrogen-rich or a reducing atmosphere were necessary. If the intense thermal conditions and/or the hydrogen were not available to the molten aluminum, the carbon present in the R-114 was found to have deposited in the process piping as a “sooty residue.”
In the fluorine-rich environment which existed in the process piping, both the aluminum carbide and the aluminum chloride were converted to aluminum fluoride. The aluminum carbide was identified in regions of the process piping where little exposure to fluorinated material existed. Many of these chemical reactions and the conditions necessary for them to take place were cited in: The Chemist, March/April 2000, pp. 21-24.
When the process piping, was opened, the solid had burst into flames. The relevant reaction is: Al 4 C 3 (s) + 6 H 2 O(g) 2 Al 2 O 3 (s) + 3 CH 4 (g) (8) The formation of aluminum oxide (Al 2 O 3 ) generates so much heat that the methane (CH 4 ) produced burst into flames; its flash point had been exceeded. When the flashing of the methane was observed, I was tasked with determining what had happened. Brady’s General Chemistry text has a section on aluminum carbide.
14 Al(s) + 3 C 2 F 4 Cl 2 (g) 4 AlF 3 (s) + Al 2 Cl 6 (g) + 2 Al 4 C 3 (s) (7) Equation (7) summarizes the catastrophic reaction of the molten aluminum with the R-114 coolant. This balanced redox reaction requires a transfer of 18 electrons! The thermodynamics associated with equation (7) and several other chemical reactions in the fire were cited in: The Chemist, September/October 2000, pp. 19-24.
On-going work Exposure to the allegedly hazardous ingredient in a commercial product. This southeastern KY legal case has demonstrated how little chemistry the attorneys for a multi-national company actually know. A group of insurance companies have paid for property damage resulting from the explosion of a fireworks magazine in western PA. My task has been to apply the chemistry and physics to determine the radius of the “circle of causation.” This is to compel the owner of the magazine to reimburse the insurers for the damage that was caused by the explosion.
Industrial troubleshooting at the Paducah Gaseous Diffusion Plant in western KY. Several legal cases are in development regarding occupational exposure and laboratory methodology throughout this country.