Feedstock Purity Calibration Solutions
All the right stuff to ensure accurate monitoring of ethylene and propylene purity in product or polymer grade feedstocks
Air Liquide Feedstock Purity Solutions include:
- 1 - 5 ppm Moisture Standard in Nitrogen
- 1 - 5 ppm Ammonia Standard in Nitrogen
- 0.1 - 1 ppm Hydrogen Sulfide Standard in Nitrogen
- 0.1 - 1 ppm Hydrogen Sulfide/Carbonyl Sulfide/Methyl Mercaptan Standard in Nitrogen
- Custom Feedstock Blend Combinations
- Zero Nitrogen (certified conformance to Federal Register specs 40CFR 72.2)
- ALPHAGAZ™ 1 pure instrument support gases
- Scott™ high-performance gas delivery equipment
Download feedstock calibration standards specifications
Impurity analysis of olefin monomers
Ethylene and propylene are two important feedstocks used as building blocks for many types of resins and plastics, such as polyethylene and polypropylene. These materials are the backbone for numerous industrial and consumer products; billions of pounds are produced every year.
Ethylene and propylene are produced by combining steam with ethane or propane feedstocks in a furnace at about 1500° under relatively low pressure. The “cracked” gas is cooled and compressed, and then the ethylene is separated from ethane by cryogenic distillation. The finished monomer product is dried over a desiccant and then distributed to petrochemical facilities through a complex network of pipelines and underground storage facilities.
Polyethylene and polypropylene are produced at petrochemical facilities using sophisticated processes and exotic catalysts whose selectivity and sensitivity increase all the time. Polymerization catalysts are themselves very expensive and are easily “poisoned” by undesirable impurities in the monomer feedstocks. Frequent catalyst replacement coupled with associated plant shutdowns result in economic losses for the producer.
Monitoring trace impurities critical
Extremely stringent purity specifications and trace impurity analysis of polymer grade ethylene and propylene, even to low ppb levels, have therefore achieved critical importance. Even though these monomers may have been produced to tight purity standards, they can pick up traces of water and other impurities during storage and transportation. As a result, polymer grade ethylene and propylene are sampled and analyzed numerous times along the supply chain, particularly where valuation and custody transfer occurs.
Some of the critical impurities listed in the table below have the power to adversely affect polymerization catalysts. For this reason, it is critical that monomer producers accurately detect and measure one or more of the specified impurities at very low levels.