Axens has been a pioneer in the development of RAM™ series processes, suitable for the processing of various liquid hydrocarbons such as saturated or unsaturated LGP or feedstocks boiling in the naphtha range or even heavier condensate fractions.
Mercury in condensates and liquid hydrocarbons can be found in metallic, ionic or organo metallic form.
When only metallic mercury is present, a simple AxTrap 273 trapping mass can be adequate and effective to meet less than 1 ppb mercury in the effluent. The adsorbent ensures high mercury capture at low temperatures.
RAM II Process
In a wide range of liquid feedstocks both arsenic and mercury are present in diverse forms, which contributes to the difficulty of their removal. Axens’ RAM II Process is specifically designed to eliminating Mercury, Arsenic and eventually Lead based compounds in a two-step, liquid phase process.
The first step requires passing the contaminant-containing feed over a hydrogenolysis catalyst in the presence of hydrogen. The catalyst causes the Hg-C and As-C bonds to rupture, generating As adsorption and metallic Hg formation. This first step utilizes a specific high performance CMG 841 catalyst which is operated mostly in liquid phase and permits the hydrogenolysis of the most refractory mercury species associated with very high liquid fraction end boiling points. It also traps arsenic compounds present in the feed
The second step involves the simple capture of metallic Hg onto selective AxTrap 273 trapping material.
To ensure long cycles and safe operation of the RAM II catalytic section when treating stored, imported or unclear feedstocks, Axens provides dedicated feed preparation for each type of feedstock that has been optimized based on extensive industrial experience. However for maximization of profitability, it is preferable for RAM II to process clear liquid hydrocarbon fractions downstream of the crude distillation or steam cracking.
Typical results are excellent, less than 1 ppb of each contaminant in the product.
In the majority of cases the mercury species present in the liquid hydrocarbons are not easily identified Axens proposes a no regret investment approach with initial implementation of the polishing step RAM II process reserved for metallic mercury capture. Where non metallic mercury breakthrough occurs the process can be enhanced to the two-step complete process.
Axens can also provide expertise and assistance for feedstock analyses and detailed determination of the nature of contaminants.
RAM III Process
As a cheaper solution when the contaminated liquid phase is destined for hydrotreatment, Axens offers the RAM III solution which is specifically designed to combine both hydrotreatment and mercury and arsenic capture in an integrated process.
The hydrotreatment reaction section utilizes a specific high activity CMG 406 catalyst which permits the hydrogenolysis of the most refractory mercury species associated with very high liquid fraction end boiling points. It also traps arsenic compounds present in the feed. Downstream of the hydrotreatment section the complete capture of metallic Hg is achieved onto selective AxTrap 273 trapping beds.
The RAM II & III processes provide a favorable return on investment by allowing the processing of lower value contaminated liquid hydrocarbon feedstock with high impurities levels in refineries and steam cracking plants.