The purpose of the FCCU is to crack lower-value feedstocks and produce higher-value light and middle distillates. The process also produces light hydrocarbon gases, which are important feedstocks for petrochemicals. The feedstocks to catalytic cracking units vary from gas oils to crude residues. The tonnage of refractory in a moderate sized refinery with FCCU is considerable. A new FCCU will use in excess of 1000 tons of refractory throughout. Considering furnaces, heaters, reformers, boilers, etc., tonnage may exceed 2500 tons. Refractory life in the FCCU is expected to last more than 10 years with turnaround maintenance every 5 years. These can require 50 to 250 tons of refractory. When the FCCU is down, many other refractory lined units are also down.

Kiriman : Hermawan

Dear millis

Salam kenal, sekedar bacaan

Refractory is one importance material in oil and gas application especially in FCCU (Fluid Catalytic Cracking Units), I want to share an article from ANH Refractories.

Fluid Catalytic Cracking Units (FCCU)

OVERVIEW:

The purpose of the FCCU is to crack lower-value feedstocks and produce higher-value light and middle distillates. The process also produces light hydrocarbon gases, which are important feedstocks for petrochemicals. The feedstocks to catalytic cracking units vary from gas oils to crude residues. The tonnage of refractory in a moderate sized refinery with FCCU is considerable. A new FCCU will use in excess of 1000 tons of refractory throughout. Considering furnaces, heaters, reformers, boilers, etc., tonnage may exceed 2500 tons. Refractory life in the FCCU is expected to last more than 10 years with turnaround maintenance every 5 years. These can require 50 to 250 tons of refractory. When the FCCU is down, many other refractory lined units are also down.

A. Cyclones:

Description:

These are basically mechanical separators used to separate the entrained catalyst particles from the product stream. The principle is based on the use of centrifugal force. The product / catalyst mixture is introduced in the side of the cyclone whereby centrifugal motion is set in place. This centrifugal motion will send the heavier particles, usually catalyst, towards the outer walls of the cyclones, while the hydrocarbon product is sent to the middle. The hydrocarbons then flow up the center for passage to the fractionation column. The critical factor here is for abrasion resistance, as these fine catalyst particles may move at speeds approaching 150 ft/sec / 100 mph. Predominately, hexmesh is used as the anchoring system with the material rammed into place. Independently placed anchors, e.g. S-bars, could prevent the sheeting action commonly attributed to the hex-mesh.

Refractory Issues:

Excellent abrasion resistance

Excellent volume stability, minimal shrinkage on drying & firing

Installation by ramming

B. Riser

Description:

The riser line is where the majority of the cracking reaction occurs. The hydrocarbon feed is intimately mixed with fresh catalyst feed and steam to keep the mixture fluid and promote the cracking of the hydrocarbon. There are two schools of thought in this application. Use of a dense, abrasion resistant material to withstand the impingement of the fluid stream and to resist the penetration of coke; or the use of a less dense material with lower thermal conductivity to better address the differential thermal expansion between metallic and refractory materials. Theoretically, no refractory lining will be impermeable to the migration of coke into the lining since this occurs as deposition from a gaseous state. Coke penetration is probably complete within the first few weeks of operation. Coke penetration will increase the thermal conductivity of the lining and can actually improve the strength and abrasion resistance of the lining. Coke penetration can also lead to failures by stress induced cracking.

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