Wax–oil solvent deoiling: methyl isobutyl ketone (MIBK) versus methyl ethyl ketone (MEK) — which advantages are commonly cited for using MIBK as the deoiling solvent for hard-wax separation?

Introduction / Context:
Solvent deoiling (or dewaxing) is used in lube and wax processing to separate oil and soft wax from hard wax. The solvent pair and operating window strongly influence filtration temperature, cake structure, and downstream recovery steps. Two common solvents are methyl isobutyl ketone (MIBK) and methyl ethyl ketone (MEK).

Given Data / Assumptions:

• Goal: achieve efficient filtration of crystallized hard wax with acceptable viscosity and crystal habit.
• Comparing general, textbook-cited advantages of MIBK against MEK in deoiling service.
• Plant context: standard chilling, filtration, and solvent recovery sequence.

Concept / Approach:
Solvent choice affects wax crystal size, slurry rheology, filtration rate, and solvent recovery. MIBK’s physical properties can allow simplified drying needs, provide a favorable operating temperature window, and require a lower solvent-to-feed (dilution) ratio for comparable separation—each of which improves operability and energy efficiency depending on the formulation.

Step-by-Step Solution:
Consider downstream handling: MIBK’s characteristics may simplify dewax cake handling and reduce separate solvent-drying steps → supports statement (a).Operating window: process temperatures compatible with MIBK can be advantageous for filtration/crystallization control → aligns with statement (b).Solvent economy: lower solvent dilution ratio reduces energy duty in recovery and improves throughput → supports statement (c).Therefore, all listed advantages can apply in typical deoiling practice.

Verification / Alternative check:
Process comparisons in refining literature often report different solvent-to-oil ratios and filtration behavior for MIBK vs. MEK systems; selection is ultimately case-specific but the combined advantages are widely cited in summary questions.

Why Other Options Are Wrong:
Choosing only a single advantage ignores the multi-factor impact of solvent properties on crystallization, filtration, and recovery.

Common Pitfalls:
Assuming one solvent is universally superior; actual choice depends on crude source, wax composition, and integration with existing solvent recovery trains.

Final Answer:
all (a), (b) & (c).