When people purchase a bottle of edible oil, be it sunflower oil, coconut oil, groundnut oil or any other, they expect a level of purity and quality which will protect their and their family’s health. They trust the producers of their oil to keep the product free of any chemical or other impurities which might impact its safety, and naturally, they also want any visible physical impurities eliminated. This is where an oil mill with filter press technology comes in – by guaranteeing production of oil of the finest quality, it will help you ensure customer safety and satisfaction and set you apart from your competitors as an oils and fats producer who can be trusted.
What is filter press technology?
Filter presses are hardly specific to the oils and fats industry; they have applications in any industry which requires the separation of solids and liquids. Filter presses can be either lab-scale or industrial-scale. And they generally can’t be operated in a continuous process, so you have to rely on batch refining to use a filter press.
At the industrial scale, they are used in cement production, mining, power generation, chemical manufacturing and as in our case here, in food and beverage processing – particularly, in the oil extraction and refining ecosystem. Given these various applications, naturally, specific use cases, like an oil mill filter machine will have a design, capacity, material of construction, filter plate size and type, and additional features including automation which suit the particular purpose. Additionally, since filter presses are more suited to batch processing, there is often more than one oil press filter machine in use – one is cleaned while the other is being operated.
In the oils and fats industry, an oil press filter machine is at the very centre of the process of manufacturing clean, clear, clarified edible oil. They transform crude oils – visibly full of solid impurities which remain even after the initial extraction process – into clear edible oils which people would trust enough to use in their kitchens
How does a filter press work in an oil mill? Usually, it consists of filter plates (or diaphragm boards) and frames, chambers into which the slurry is injected, and filter paper, cloth or membranes through which filtration occurs. Solid components are separated from the liquid using pressure filtration – the oil, with its suspended impurities, is injected into the press, filling the chambers which make up the oil press filter machine. To make sure that the maximum amount of visible impurities are removed, the crude oil is pumped into the oil press filter machine in such a way that the solids are evenly distributed. As the chambers fill, the pressure in the system rises, aiding the process. Pressuring air or water may also be used to strain the crude oil through the filters. The solids build up on the filter, forming a cake, while the clarified oil – the filtrate – is collected and either packaged or taken to the next step of the refining process.
Every oil mill with filter press technology has a different design, depending on the type and viscosity of oil being produced, and volume and type of slurry that needs to be filtered. Good oil mill machinery manufacturers take into account the features of your specific process and customize oil mill expeller machines and oil press filter machines for you to maximize throughput in your plant. For instance, an oil mill with filter press is central to shea butter processing – a boiler, mechanical press and filter press are the main equipment involved. In the coconut oil extraction and refining process, however, filtration happens not only right after extraction using a plate and frame filter press, but also after bleaching, when bleaching agents used to eliminate pigments need to be removed as well (more on this below).
Types of filter presses
Filter presses come in a variety of design configurations, each using a slightly different mechanism to produce the clear oil your customers want. Investing in an oil mill with filter press technology involves several conversations with your oil mill machinery manufacturers to assure you that you are getting the oil mill expeller and allied equipment best suited to your facility in terms of type and scale.
Ideally, in sanitary industries like food and beverage, high grade stainless steel material should be used to construct an oil mill with filter press. This will not just ensure compliance with market standards, but it will also help you rest assured that rust, corrosion, or any other material issue doesn’t affect the integrity of your process. Once these basics regarding material of construction are covered, there are different types of filter presses to choose from.
There are plate type filter presses, plate and frame type, membrane filter presses, pressure leaf filters, and centrifugal filter presses. They each come employ different mechanisms, have different cake holding capacity, filtering area, and pump motor power. For example, Kumar’s plate type oil press filter machines have cake holding capacities ranging from 0.4 cubit feet to 19 cubic feet, while the plate and frame type filter presses go all the way up to 37 cubic feet. Kumar’s different filter presses also have filtering areas starting from 5 square feet to 215 square feet, covering all of your oil filtration needs.
Applications of filter press technology in an oil mill
There are at least three steps in the oil processing journey that rely on filter presses.
- After expelling
For starters, when you mechanically extract oil using an oil mill expeller machine, some solids get left behind in the expelled oil because the oilseeds are disintegrated to small sizes to easily extract the oil. These suspended particles are usually filtered out using plate type filters which have a high rate of filtration and leak proof joints which can withstand the operating pressure of such a technique.
- After bleaching
Some edible oils need to be bleached during the refining process because the crude oil has colour pigments and traces of soap which can impact the safety of the product and the perception of its quality. Crude oil is bleached by adding bleaching earth and activated carbon under specific vacuum and temperature conditions. After the impurities are removed, the spent bleaching earth and carbon needs to be eliminated, for which a pressure leaf filter can be used. It is only after such filtration does the oil move on to the deodorization step.
- As part of the fractionation process
In some refined oils, triglycerides of high and low melting points need to be separated. The process of fractionation involves crystallising such oils at low temperatures, followed by filtration, to separate the solid and liquid fractions. Membrane filter presses are usually used in dry fractionation – a process common in the refining of tropical oils like palm oil and palm kernel oil.
Ultimately, filtration is a process common across industries and within the oils and fats processing industry. Investing in an oil mill with filter press technology is a no-brainer if you want to be an industry leader who prioritises safety, quality and efficiency. Kumar is one of the few oil mill machinery manufacturers who provides a performance guarantee while focusing on operational profitability as well as sustainability. Talk to us at Kumar for all your oilseed processing needs.
Request a callback
Since 1939, Kumar has been delivering dependable process engineering solutions to the oils and fats industry. We're known for our robustly engineered, versatile, and operationally profitable plant and machinery. It's why customers all over the world depend on us to solve their processing challenges, big or small. If you'd like to know more about our solutions, please fill out the form below:
"*" indicates required fields