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Hydrogen Properties for Energy Research (HYPER) Lab Ian

ME 527 Lesson 39: Fluid Friday – Helium

We’ve now come to an end of our list of cryogenic fluids arriving at helium:

  1. Krypton (119.73 K)
  2. Methane (111.67 K)
  3. Oxygen (90.188 K)
  4. Argon (87.302 K)
  5. Fluorine (85.037 K)
  6. Carbon Monoxide (81.64 K)
  7. Nitrogen (77.355 K)
  8. Neon (27.104 K)
  9. Deuterium (23.31 K)
  10. Hydrogen (20.369 K)
  11. Helium (4.222 K)

Discovery, origins, and current usage

Evidence of helium was first discovered in 1868 while looking at spectral lines of our sun. It was later liquefied by Kammerlingh-Onnes, who discovered it’s supercritical properties and won the Nobel prize.

 

Fixed Properties

Helium is unique among the cryogenic fluids due to a change of phase from classical to quantum fluid behavior known as a superfluid. This occurs at what is known as the Lambda line, or lambda point (2.17 K at 1 atm):

In the superfluid state the liquid is quantized with no viscosity, extremely fast thermal conductivity and sound speed, etc.

Obviously below the lambda line our classical “macroscale” thermodynamics ceases to remain valid. That’s why we’re restricting ourselves to helium I.

Helium EOS fixed points

Surface of State

Helium Pressure versus Temperature

Helium Pressure versus density

Helium isochoric heat capacity versus temperature

Helium sound speed versus temperature

Helium Gruneisen versus Temperature

Helium phase identification parameter versus temperature

 

ME 527 Lesson 36: Fluid Friday – Deuterium

Now that we are familiar with hydrogen, we will cover it’s only stable isotope, Deuterium on our list of cryogenic:

  1. Krypton (119.73 K)
  2. Methane (111.67 K)
  3. Oxygen (90.188 K)
  4. Argon (87.302 K)
  5. Fluorine (85.037 K)
  6. Carbon Monoxide (81.64 K)
  7. Nitrogen (77.355 K)
  8. Neon (27.104 K)
  9. Deuterium (23.31 K)
  10. Hydrogen (20.369 K)
  11. Helium (4.222 K)

Introduction and Discovery

Deuterium, also known as heavy hydrogen, is one of two stable isotope of hydrogen. Deuterium comes from the Greek deuteros meaning “second” referring to the two particles (proton + neutron) in the nucleus.  Deuterium accounts for 0.0156% of the hydrogen in the oceans or one in 6420 hydrogen atoms.  Deuterium was created during the Big Bang and accounts for 0.0013% of the Universe.

Deuterium was discovered by Harold Urey in 1931.  He predicted that their would be a difference between the vapor pressure of pure hydrogen and it’s heavier isotopes. He developed a method to isolate the heavier isotope through the distillation of liquid hydrogen. This lead to Urey receiving the Nobel Prize in Chemistry in 1934 “for his discovery of heavy hydrogen”.

Similarly to hydrogen, deuterium also has 2 spin isomers denoted as orthodeuterium and paradeuterium. Contrary to hydrogen and tritium, the lower-energy, even-states are denoted “ortho” for deuterium, while the higher-energy, odd-J states are denoted “para.” This is due to the ortho-para compositions at room temperature are different for deuterium than they are for hydrogen because deuterium has nuclear spin of +1 whereas hydrogen has a nuclear spin of +1/2.

Uses and Production

Deuterium is used as fuel in nuclear fusion reactors like the National Ignition Facility (NIF) and ITER (in development). Deuterium is also used in NMR spectroscopy, as a stable isotope tracer, nuclear weapons, and medicine for deuterated drugs.  Research grade deuterium gas costs $1,112 for 500 standard liters which equates to $12.38 per gram!  This price can be reduced to $1/L for larger orders of research grade deuterium.  Due to the military applications, the deuterium market is very secretive and little information is available to the public. After a discussion with a Linde representative, I was able to learn that the deuterium market has rapidly grown over the last 10 years because of it’s use in the manufacturing of semiconductors and fiber optics. Linde is the largest producer of deuterium in the world producing millions of liters a years.

Due to the small differences in molecular mass, it is energy intensive and expensive to separate the isotopes of hydrogen.

H2 Combinations

Deuterium can be separate from the other hydrogen isotopes through several processes including chemical exchange, thermal diffusion, cryogenic distillation, electrolysis, and permeation.The most common method for producing deuterium is through electrolysis of heavy water, D2O, which is widely used in heavy water reactors. Until it’s closure in 1997, the Bruce Heavy Water plant in Ontario, Canada was the largest producer of D2O utilizing the Girdler Sulfide process.  This is an isotopic exchange process between H2S and H2O:  H2O + HDS ⇌ HDO + H2S. After several iteration this process is able to enrich the water to 15-20% D2O where it can then be purified using distillation or electrolysis.  This process takes 340,000 kg of feed water to produce 1 kg of heavy water.

D2O Production Overview

Canada is the largest producer and consumer of heavy water where it is used to cool their CANDU reactors. The price of heavy water is $300 per kg (2001).

D2O Production

 

 

Fixed Properties

D2 Fixed Properties

Surface of State

Only the equation of state for normal deuterium is included in REFPROP.  The variation in thermophysical properties between orthodeuterium and paradeuterium were not significant enough to warrant separate equation to be include in REFPROP.

Critical Isotherm

Though the rectilinear diameter has a slight change in the curvature, the critical isotherm exhibits correct thermodynamic behavior.

D2 Extrapolation

Extrapolating to extreme pressures and densities shows the equations behaves theoretically correct at the high extremes.

Cv-T

The Cv vs. T plot for deuterium behaves similar to traditional fluids with saturated vapor line crossing the saturated liquid line.

w-T

The deuterium equation was complete in 2013 and is a 21 term, Helmholtz explicit equation of state.

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TRITIUM

Tritium is the heaviest of the hydrogen isotopes having 2 neutrons.  Tritium is highly radioactive having a half-life of 12.3 years.  Tritium is very rare in nature accounting for only 3 in 10^18 atoms of hydrogen.  The radioactive decay causes phosphors to glow making it useful for self-power lighting in devices like watches, exit signs, firearm sights, etc.  Tritium is also used in nuclear weapons and as fuel for fusion reactors like ITER and NIF.  Tritium costs a staggering $30,000 per gram.  The commercial demand is 400 grams per year.  Pure tritium is produced  by cryogenically distilling enriched deuterium gas streams that have been electrolyzed from the heavy water CANDU reactors.

Cryo Distillation

 

 

 

 

There are only a handful of vapor pressure and density experimental measurements for tritium. The available information on the critical and triple point properties are discussed below:

Tritium Properties

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A Helmholtz explicit equation of state does not exist for tritium.

Ortho–Para Effects on Hydrogen Mixture Measurements

While conducting composition measurements on helium-hydrogen mixtures using a Varian gas chromatograph at WSU’s Analytical Chemistry Service Center, I discovered that the ratio of orthohydrogen–parahydrogen has a significant effect on the measurements.  An in depth discussion of the allotropic forms of hydrogen can be found in the previous post “Why equilibrium hydrogen doesn’t exist”.  In my system, gaseous hydrogen is condensed in a copper test cell at 20 K.  An ortho-para catalyst is placed in the bottom of the test cell to ensure all of the hydrogen is converted to parahydrogen. Helium gas is then introduced into the test cell to the desired pressure. The amount of helium that dissolves into the liquid is measured by extracting a liquid sample through a tube at the bottom of the test cell where it is vaporized and collected in a gas sampling bag.  The composition of the sample is then analyzed using gas chromatography.  The total composition of the first helium-hydrogen measurements were only totaling between 80% – 90% instead of the expected 100%. The GC column was packed with a hydrogen compatible material so it was unlikely the equipment was causing the discrepancy.  We double checked that the primary standard gas mixtures were still obtaining correct measurements, they were. The only difference was that the gas standards contained normal hydrogen (since they were maintained at room temperature) and the samples being collected were parahydrogen.  By adding an ortho-para catalyst just before the mixture was collected in the sampling bag, I was able to convert the hydrogen back to the normal composition.  After this was implemented, every gas sample measurement was within the uncertainty of the equipment.  Once again, the subtle differences between orthohydrogen and parahydrogen cannot be overlooked even in a process as standardized as gas chromatography.

Toyota Mirai Pictures

To go along with the other Toyota Mirai post, I was wandering around Tokyo on Wednesday and stumbled across the Toyota showroom.  They had a Mirai and labelled chassis on display as well as demo hydrogen fueling nozzles.

IMG_2294 IMG_2296 IMG_2297 IMG_2298 IMG_2301

WSU Rubotherm System Overview and Experimental Capabilities

Rubotherm IsoSORP instruments utilize a Magnetic Suspension Balance to provide highly accurate fluid density and sorption measurements. The system utilizes Archimedes’ principle to determine fluid density by suspending a sinker of known mass and volume in a fluid and measuring the weight with a precision balance. The applied force is transmitted to the balance by the magnetic suspension which decouples the testing fluid from the balance. The Rubotherm IsoSORP at Washington State University has recently been retrofitted for cryogenic temperatures and pressure up to 4000 psi. By placing the test cell in a vacuum chamber and thermally connecting it to a Cryomech cryocooler I have been able to achieve temperatures down to 15 K. A system diagram is provided in Figure 1 showing the key components. Sorption measurements are conducted by replacing the bottom sinker with a weighing basket filled with the sorption material and measuring the change in mass. The system is currently set up to conduct density measurements with a single quartz sinker.

The system’s operation and accuracy has been validated by conducting initial density measurements of liquid nitrogen and liquid hydrogen. Initial liquid nitrogen density measurements conducted from 79.6 K to 83.7 K had a maximum deviation of 0.08% from the equation of state. Initial normal liquid hydrogen density measurements were conducted from 16 K to 32 K with a maximum deviation of 0.3% from the equation of state. High density (> 52 kg/m3) gaseous hydrogen measurements were conducted from 34 K to 45 K and pressure up to 1090 psi with a maximum deviation of 0.3%.

The Rubotherm system at WSU is capable of conducting pure fluid density and sorption measurements from 15 K to 293 K at pressure up to 4000 psi. We are in the process of modifying the system to have the ability to conduct measurement on binary mixtures using mass spectroscopy to determine fluid composition. The accuracy of this system increases with fluid density. The current system configuration is not intended for low density gaseous measurements.

WSU Rubotherm system diagram.
Figure 1. WSU Rubotherm system diagram.

H2 Fuel Station Mentioned in Alaska Airlines Magazine

The award winning hydrogen fuel station designed by Ian Richardson, Jake Fisher and Dr. Jake Leachman was mentioned in the latest version of Alaska Airline’s Magazine.  The excerpt is available here on page 34 or is provided bellow.

“In May, a team comprising WSU students and one University of Idaho student-involved in academic tracks ranging from mechanical engineering to economics and public policy-won first place in an international student competition to design a transportable, stand-alone, economical refueling station for hydrogen fuel cell-power cars, whose use may help reduce carbon dioxide emissions.”

Washington State University