Cryogenic Krypton Xenon Neon And Helium Gas Production Plant
Rare gases, also known as noble gases, are the most inert and unreactive elements known to man. They are found in very low concentrations in the environment (0.001818% neon, 0.000114% krypton and 0.0000087% xenon) and are manufactured by Air Separation Units (ASU). Due to their unique chemical properties, experts have found very novel and interesting applications for them.
Most rare gases are very stable, as such their ionization energy is very high. That makes them very useful as ion beam sources to clean, cut or weld materials.
Another property is their unique ability to produce bright light, which may be in the form of a laser (neon/helium laser) or a light source (xenon). Finally, they are very heavy and dense gases, so they are used in propulsion engines or in window insulation. Rare gases are so called because they are present in very small quantities in the air.
Xenon is rare with only 90 gram out of 1 million kilograms of the Earth's atmosphere. It is commercially extracted only from large air separation plants which produce more than 1,000 tonnes of oxygen per day.
WOBO has efficient purification technologies required to remove impurities like argon and nitrogen which are very inert. We transfill rare gases into cylinders in our high purity plants in Asia to be used in high value industry segments.
The separation of krypton, xenon, neon, and helium in cryogenic space typically involves a multistage process known as cryogenic distillation or cryogenic fractional distillation. This process takes advantage of the different boiling points of these gases to separate them based on their relative volatilities. Here's a general description of the process:
1. Compression: The gas mixture containing krypton, xenon, neon, and helium is first compressed to increase the pressure. This helps in preparing it for subsequent cooling stages.
2. Precooling: The gas mixture undergoes precooling using heat exchangers. It is typically cooled by counter-flowing against a colder gas or liquid, such as liquid nitrogen or liquid oxygen, to remove some of the heat and reduce the temperature.
3. Initial Separation: The pre-cooled gas mixture is then introduced into a column, typically a distillation column or a fractionation column. This column consists of multiple stages or trays. As the mixture flows upwards, it is subjected to further cooling and partial condensation.
4. Fractionation: The column is equipped with a reboiler at the bottom and a condenser at the top. Heat is applied to the reboiler, causing the liquid at the bottom to vaporize and rise through the column. As the gas mixture ascends, it starts to condense at different stages, with the heavier components condensing at lower stages and the lighter ones condensing at higher stages.
5. Reflux: The condensed liquid from the top of the column, known as the overhead product, is collected and partially refluxed back into the column. This reflux helps enhance the separation efficiency by washing down the heavier components, allowing for further purification.
6. Product Collection: At various stages of the column, different fractions enriched in krypton, xenon, neon, and helium are collected as individual products. The precise collection points are determined by the boiling points and volatilities of the gases.
7. Repetition and Optimization: The distillation process is typically carried out in multiple columns or repeated stages to achieve higher purities and recoveries of the desired gases. The conditions of temperature, pressure, and reflux ratio are adjusted to optimize the separation efficiency.
impurities ppm |
N2 |
O2+Ar |
H2 |
CO |
CO2 |
CH4 |
Xe |
Design |
1.5 |
0.5 |
0.5 |
0.1 |
0.1 |
0.1 |
Actual |
0.3 |
0.1 |
<0.1 |
<0.1 |
<0.1 |
<0.1 |
Kr |
Design |
2 |
1.5 |
1.5 |
0.3 |
0.4 |
0.3 |
Actual |
0.3 |
<0.1 |
<0.1 |
<0.1 |
<0.1 |
<0.1 |
Yield |
100~400Nm3/h |
impurities ppm |
N2 |
O2+Ar |
H2 |
CO |
CO2 |
CH4 |
H2O |
He |
Design |
1.5 |
0.5 |
0.5 |
0.5 |
0.5 |
0.5 |
1 |
Actual |
<0.1 |
<0.1 |
<0.1 |
<0.1 |
<0.1 |
<0.1 |
<0.2 |
Ne |
|
0.5 |
1 |
1 |
0.2 |
0.2 |
0.1 |
0.2 |
Actual |
<0.2 |
<0.1 |
<0.1 |
<0.1 |
<0.1 |
<0.1 |
<0.2 |
Yield |
10~100Nm3/h |
|
1. Independently developed, designed, and manufactured high-purity krypton-xenon-neon-helium extraction and separation equipment.
2. The purity of krypton gas, xenon gas, neon gas, helium gas, carbon dioxide, and liquid oxygen can all reach 6N (99.9999%),fully meeting the requirements of industries such as semiconductors, flat panel displays, aerospace, and medicine.
3. The domestically produced and operated largest neon-helium separation equipment, with a neon gas production capacity of up to 90,000 Nm3/year, has provided more than 20 sets of krypton-xenon pre-concentration equipment and 8 sets of krypton-xenon refining equipment to domestic and foreign manufacturers.
4. The cryogenic air separation equipment can be scaled up or down according to the required production capacity. Whether it is a small-scale laboratory setup or a large-scale industrial factory, cryogenic distillation technology offers flexibility and scalability to meet different production requirements.
5. The cryogenic air separation process has a relatively low environmental impact. Gases are cooled and distilled at low temperatures without the need for chemical reactions or significant energy-intensive processes. Recovered gases, especially helium, are a limited and valuable resource that can be effectively protected and utilized.
6. Customized production can be achieved to meet the diverse needs of different customers.
Neon/Krypton/Xenon/Helium Major Applications
Krypton (Kr):
1. Lighting: Krypton is used in certain types of incandescent lamps and fluorescent lights to enhance their efficiency and color rendition.
2. Laser Technology: Krypton is utilized in gas lasers, particularly in high-power and excimer lasers, for applications such as scientific research, laser cutting, and medical procedures.
3. Insulating Windows: Krypton is sometimes used as a fill gas in insulating windows to improve their energy efficiency by reducing heat transfer.
Xenon (Xe):
1. Lighting: Xenon is commonly used in high-intensity discharge (HID) lamps, such as automotive headlights and cinema projectors, due to its high brightness and color temperature.
2. Medical Imaging: Xenon is employed in xenon CT and xenon MRI techniques to image lung ventilation and enhance the quality of magnetic resonance imaging.
3. Space Propulsion: Ion thrusters, which use xenon as a propellant, are utilized in spacecraft propulsion for missions requiring precise control and long-duration thrust.
Neon (Ne):
1. Neon Signs and Lighting: Neon gas is widely used in signage and lighting due to its distinctive bright red-orange glow. It is often mixed with other gases to produce a range of colors.
2. High-Voltage Indicators: Neon lamps are utilized as visual indicators in electronic devices to show the presence of voltage or signal.
3. Cryogenics: Neon is used as a cryogenic refrigerant in certain applications that require extremely low temperatures.
Helium (He):
1. Balloons and Airships: Helium is commonly used to fill balloons and airships due to its lighter-than-air properties.
2. Cryogenics: Helium is used as a cryogenic coolant in various applications, including superconducting magnets in MRI machines and particle accelerators.
3. Leak Detection: Helium is an ideal gas for leak detection due to its low concentration in the atmosphere and its ability to easily penetrate small leaks.