Sodium silicate as a coke inhibitor during naphtha pyrolysis

Abstract

Rates of coke formation during steam pyrolysis of naphtha have been investigated in a jet‐stirred reactor both for sodium silicate coated and uncoated Inconel 600 surfaces in the temperature range of 1078–1108 K. Coke formation rates were significantly reduced on sodium silicate coated plates due to the passivation of the metal surface. However, the coking rates gradually increased with successive decokings of the coated surface.

Influence of Silicon and Silicon/Sulfur-Containing Additives on Coke Formation during Steam Cracking of Hydrocarbons

“…Sulfur-containing compounds have been successfully used to control the CO production. For the suppression of coke, a lot of effort has been made in the past 30 years to find appropriate methods and additives. − Investigations concerning the effect of S-containing compounds have been carried out in laboratory-scale reactors. The reported effect is contradictory. ,− Besides S-containing compounds, other chemicals have been proposed as additives to suppress coke formation in steam cracking.…”

“…The reported effect is contradictory. ,− Besides S-containing compounds, other chemicals have been proposed as additives to suppress coke formation in steam cracking. These mainly include phosphorus-containing compounds, − silicon-containing compounds, − alkali and alkaline earth metal salt based additives, , and tin- and antimony-based additives. − By now none of these additives have been widely applied in steam cracking.…”

“…The optimal application method for a specific additive depends mainly on the properties of the additives. Si-containing compounds have been reported to be able to suppress coke formation in steam cracking. − These additives are commonly used to pretreat the inner surface of the cracking coils. This method offers the advantage that the pretreatment with silicon and silicon/sulfur-containing additives can be carried out at conditions similar to the decoking/cracking operations.…”

Effect of sulfur additives on coke formation during steam cracking of naphtha

“…Advanced Metallurgy and Reactor design which is used in design level for example application of three-dimensional reactor configurations such as MERT technology which improve the heat transfer leading to lower temperatures at the coke-gas interface and help to lower the coking rates, 2. Surface Treatment and Coating: [5][6][7][8][9][10][11][12][13] This approach is less preferred in industrial reactors due to the fear of leaching of coating materials, 3. Additive dosing: In this method, additives are introduced into the reactor either dissolving in hydrocarbon or water feed.…”