Membrane applications and research in the edible oil industry: An assessment

Abstract

Commercial sources of edible oils and fats include oil‐seeds, fruit pulps, animals and fish. Oilseeds processing typically consists of the following steps: i) seed preparation; ii) solvent extraction of flakes and/or extruded collets; iii) desolventization of the meal;iv) recovery of solvent by distillation; and v) degumming, refining, bleaching, and deodorizing of the crude oil. The process consumes large amounts of energy—in the forms of electricity, natural gas and fuel oils—to heat and cool the oil between individual processing steps and to generate high vacuum. Steam requirements for producing edible oil from crude oil range from 2000 to 4000 Btu/lb depending on the type of oil processed. The processing of cottonseed, corn, peanut and soybean oils alone consumes approximately 64.7 trillion Btu/yr of energy in the United States (based on 15.1×109 Ib crude oil processed). Electricity requirements for a typical refinery are between 120,000 kWh and 160,000kWh/yr (based on 1400 to 1800 kWh/22,000 Ib crude oil processed/hr). Current membrane separation research, as applied to miscella distillation; vapor recovery; condensate return; wastewater treatment; degumming, refining, and bleaching; hydrogenation catalyst recovery; oilseed proteins; and nitrogen production, is reviewed in this paper. The greatest potential for energy savings of 15 to 21 trillion Btu/yr exists in replacing or supplementing conventional degumming, refining, and bleaching processes. Decreased oil losses and decreased bleaching earth requirements are other potential advantages of membrane processing. Approximately 2 trillion Btu/yr could be saved using a hybrid membrane system to recover solvents in extraction of crude oils. Although marginal success has been reported to date, the development of hexane‐resistant membranes may make this application viable.

Production of structured lipids by lipase‐catalyzed interesterification in a flat membrane reactor

“…The applications usually improve the process of production, such as shortening the process, decreasing the temperature, leading the reaction to a specific direction, etc., and have many advantages over other separation techniques (2). Most investigations of membrane applications in lipid separation have been focused on the recovery of solvent from micella, separation in degumming, refining and bleaching, condensate return, catalyst recovery (2)(3)(4), hydrolyses of oils and fats (5)(6)(7)(8), or the syntheses of acylglycerols in two-phase membrane reactors (9). The direct separation of free fatty acids (FFA) from triacylglycerols was also investigated in a membrane reactor (10) and a review on enzymatic membrane reactors has been published (11).…”

“…When the permeation flux of PUFA is much lower than that of MCFA (J PUFA << J MCFA ), MCFA is removed from the reaction environment and the equilibrium is pushed toward the SL side. According to the fundamental theory (1), the flux of FFA can be written as: [3] where C a and C b are the concentrations of FFA in Chamber A and B, respectively; k is a constant, which is related to the overall mass transfer coefficient and reactor configuration; and J FFA is the flux of FFA. There are three cases for Equation 3 to be considered.…”

Studies towards understanding the effect of hexane on polysulfone membranes

“…vegetable oil refining, degumming process, deacidification and solvent recovery. In this regard, only a few research reports are available in open literature [1][2][3][4][5][6]. Ngyuen et al [7] observed that solvents (viz.…”

Reduction in Oxidation Index Value of Fish Oils Using Hydrophobic Nonporous Denser Membrane Process

“…Researchers are looking at membrane technology as an alternate process to the conventional refining of edible oils (Koseoglu andEngelgau, 1990, Snape andNalajima, 1996).…”

“…The membrane process is remarkably simple, offering many advantages over conventional processes, namely, low energy consumption, ambient temperature operation, and retention of nutrients and other desirable components (Koseoglu and Engelgau, 1990). Recently, a refining process of vegetable oils using a hydrophobic nonporous denser membrane has been created.…”