Refining of Palm Oil: Part 2

Summary

In this lecture, Professor Bill Curran from Designs Malaysia discusses the refining processes for crude palm oil. He covers both chemical and physical refining, explaining key stages such as gumming, neutralization, bleaching, and deodorization. The gumming process removes phosphatidyls from the oil using water or acids like phosphoric acid. The neutralization process neutralizes free fatty acids, and bleaching reduces color and removes impurities. Deodorization, the final step, involves steam distillation to eliminate volatile compounds, producing refined, bland, and odorless oil. The process ensures high-quality oil suitable for various applications.

Takeaways

• 😀 The refining process of crude palm oil involves both physical and chemical refining methods.
• 😀 The gumming process removes gummy or phosphatidyl materials from crude oil using hot water or acid, such as phosphoric or citric acid.
• 😀 In chemical refining, alkali (such as sodium hydroxide) is added to neutralize free fatty acids and form soap, which is separated by centrifugation.
• 😀 Bleaching is used to remove coloring compounds like carotene and chlorophyll from crude oil, typically using bleaching earth or clay.
• 😀 After bleaching, the oil undergoes a filtration process to remove residual adsorbents and impurities.
• 😀 The deodorization or 'deodorizing' process is crucial for removing volatile components like free fatty acids and ketones, making the oil bland and odorless.
• 😀 The deodorizers work under high temperatures (230–270°C) and vacuum, where volatile compounds are separated from the oil through steam distillation.
• 😀 Physical refining includes gumming, bleaching, and deodorization steps but without the use of alkali for neutralization, focusing on removing free fatty acids via steam distillation.
• 😀 In physical refining, the oil is initially heated and mixed with acid (usually phosphoric acid) to remove gums before bleaching and deodorizing.
• 😀 The final refined oil can be used for cooking, selling, or manufacturing other oil products, while the residual volatile components are collected as distillates for further use in pharmaceuticals or cosmetics.

Q & A

What is the primary goal of refining crude palm oil?

The primary goal of refining crude palm oil is to remove impurities such as free fatty acids, gums, coloring compounds, and other unwanted substances to produce a clear, neutral-tasting, and odorless oil suitable for consumption.

What are the main steps in the chemical refining process of crude palm oil?

The main steps in the chemical refining process are heating, degumming, neutralization, bleaching, and deodorization. These steps remove impurities like phospholipids, free fatty acids, coloring agents, and volatile compounds.

What is the role of the degumming process in oil refining?

The degumming process removes phospholipids, also known as gums, from crude oil. This is crucial as these gums can affect the stability and quality of the oil. Degumming can be done using water or acids like phosphoric or citric acid.

How does the neutralization process work in chemical refining?

In the neutralization process, alkali (typically sodium hydroxide) is added to the oil to neutralize free fatty acids. This reaction forms soap stock, which is then separated from the oil using a centrifuge.

Why is bleaching necessary in the oil refining process?

Bleaching is necessary to remove unwanted color compounds such as carotene and chlorophyll, along with other impurities like aldehydes, ketones, and trace metals. This step helps in reducing the color of the crude oil and improving its clarity.

What is deodorization, and how is it achieved in oil refining?

Deodorization is the process of removing odors and volatile compounds from the oil, including free fatty acids. This is achieved through steam distillation under vacuum conditions at high temperatures, which makes the oil colorless, odorless, and neutral-tasting.

What is the difference between chemical and physical refining processes?

The key difference between chemical and physical refining is that chemical refining involves the use of alkalis and acids to neutralize free fatty acids and remove gums, while physical refining uses high temperatures, vacuum, and steam to remove impurities without the use of chemicals like alkalis or acids.

In physical refining, why is degumming important?

Degumming in physical refining is important to remove phospholipids (gums) from crude oil, similar to chemical refining. This process is usually done with water or steam, helping to improve the oil's quality before further processing.

What compounds are targeted during the deodorization step in both refining methods?

During deodorization, free fatty acids, volatile compounds, and trace metals are targeted. The process uses steam distillation under vacuum conditions to remove these components, leaving the oil colorless, tasteless, and odorless.

What is the role of bleaching earth in the refining process?

Bleaching earth, or activated clay, is used to adsorb color compounds like carotene and chlorophyll, as well as trace metals, aldehydes, and ketones. This step is crucial in both chemical and physical refining processes to reduce the oil’s color and improve its purity.