Advancing slurry oil clarification with electrostatic separation Advantages of electrostatic separation over mechanical filtration for slurry oil clarification, particularly in terms of product purity, oil yield, and reduced Opex
Victor M Scalco General Atomics
W ith increasing demand for higher product yields and operational efficiency in refineries, the clarification of slurry oil (also known as clarified oil or cycle oil) is under renewed scrutiny. Two primary technologies emerge from extensive research as a solution for solids removal from slurry oil. To address the industry’s need for increased profits in petrochemical production, one cannot overlook the waste streams affected by this process. The refining and petrochemical industries are facing a variety of challenges in propylene production with heavier crude slates. More importantly, chasing propylene production with today's technology, the process of steam cracking has left market demand-supply gaps open for revisiting old processes. Historically, fluidised catalytic cracking (FCC) and the increasingly preferred residual fluidised catalytic cracking (RFCC) have been the main processes for upgrading low-value feedstocks into higher-value products. In today’s advanced refining industry, modern FCC/RFCC technologies are designed to drive higher propylene yields, increasing profits and improving a refinery’s bottom line.
While increasing higher-value yields throughout a refinery is beneficial to the refiner, managing fines control in concentrated residual slurry becomes a greater challenge. Mechanical filtration (such as pressure leaf or cartridge filters) and electrostatic separator systems, developed by General Atomics, both address these issues. This article examines comparative cost-effectiveness, operational performance, and optimal use cases for each technology.1 Slurry oil, a byproduct of the FCC process, serves as a valuable feedstock in carbon black production, fuel blending, marine fuel, and needle coking applications (see Table 1 ). Clarification to remove catalyst fines is essential for maximising product value and protecting downstream equipment. It is important to understand the key differences between the two technologies to emphasise profitability, preferred applications, and the marketing impact of utilising the wrong technology for certain applications when selecting clarification systems. Electrostatic separation technologies, such as the Gulftronic system, have introduced new economic and operational advantages over common
Markets served by slurry oil filtration
Market
Solids quality requirements
Profit sensitivity $10-$28 per bl $6-$12 per bl $12-$18 per bl $18-$36 per bl $22-$32 per bl
Carbon black feedstock
10-500 ppm 50-150 ppm
Fuel oil blending
Marine fuels
50-75 ppm 0.5% sulphur
Refinery residue upgrade
10-50 ppm 25-100 ppm
Needle/anode coke
Table 1
Refining India
57
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