Introduction
Planning a solvent extraction, biodiesel, oleochemical or specialty-fats project? This FAQ answers the technical and commercial questions investors, plant owners and project managers ask us most often. Fostechno Process & Engineering Pvt. Ltd. designs, manufactures and supplies turnkey plants from 5 to 1000 TPD+ for clients across India, Bangladesh, Uzbekistan and other countries. For edible oil refinery questions, see our Edible Oil Refinery FAQ.
Solvent Extraction Plants
What is the difference between direct solvent extraction and pre-press solvent extraction?
Direct solvent extraction is used for low-oil materials such as soybean, rice bran and oil cakes: the material is prepared into flakes or pellets and sent straight to the extractor. Pre-press solvent extraction is used for high-oil seeds like sunflower, mustard, groundnut and cottonseed: an expeller first removes most of the oil, and the remaining cake goes to the extractor. Choosing the right route has a direct effect on oil yield, power use and meal quality. Read more in our beginner’s guide to solvent extraction plants.
Which raw materials can a Fostechno solvent extraction plant process?
Our plants are designed for oilseeds and oil cakes including soybean, sunflower, mustard/rapeseed, cottonseed, groundnut, rice bran, sesame and other expeller cakes. Each material needs a different preparation section, extractor residence time and desolventizing setup, so we design the plant around your main feedstock and the seeds you may switch to later. See our guide on solvent extraction applications by seed type.
How much oil is left in the de-oiled cake after solvent extraction?
A well-run solvent extraction plant usually leaves about 0.5–1% residual oil in the de-oiled cake, compared with roughly 6–10% in cake from mechanical expellers alone. That difference is the main reason solvent extraction pays back: the extra oil recovered from every ton of cake adds directly to revenue. The exact figure depends on seed preparation, flake thickness, extractor design and operating discipline.
Which solvent is used in solvent extraction, and is the oil safe to eat?
Food-grade hexane is the standard solvent for edible oil extraction. After extraction, the hexane is fully separated from the oil through miscella distillation and stripping, and from the meal through desolventizing. The crude oil is then refined, and deodorization removes any remaining volatile traces. When the plant is correctly designed and operated, the finished oil meets food safety norms for residual solvent.
What is miscella distillation and why does it matter?
Miscella is the mixture of oil and hexane that comes out of the extractor. Miscella distillation separates the two through evaporators and a stripping column under vacuum, so the oil comes out solvent-free and the hexane can be reused. Good distillation design protects oil colour and quality, cuts steam use, and is one of the biggest factors in keeping solvent loss low.
How is hexane recovered and reused in a solvent extraction plant?
Hexane vapours from the extractor, desolventizer and distillation section are condensed and collected for reuse. Vapours that do not condense are sent through a mineral oil absorption (vent recovery) system, which captures the remaining solvent before air is released. The recovered hexane goes back into the process in a closed loop, which lowers operating cost and improves plant safety.
What happens to the meal after extraction?
The wet meal leaving the extractor still contains hexane. It goes through a desolventizer-toaster-dryer-cooler (DTDC), which removes the solvent, toasts the meal to improve its feed value, dries it to safe moisture levels and cools it before storage. The finished meal is then conveyed to meal cooling and bagging for dispatch.
What is de-oiled cake used for, and how is it sold?
De-oiled cake (DOC) is a protein-rich ingredient used mainly in poultry, cattle and aquaculture feed. Soybean meal, mustard DOC and rice bran DOC are traded in domestic markets and exported. Its price depends on protein content, residual oil, moisture, fibre and colour, so a well-designed DTDC and meal handling section directly improves the money you get for the meal.
Can one solvent extraction plant process more than one type of seed?
Yes, a multi-seed plant can be engineered to handle two or more materials, for example soybean and mustard cake, or rice bran and other cakes. The preparation section, conveyors and extractor settings must be sized for the most demanding material. Planning this at the design stage avoids costly changes later and lets you switch raw material with the seasons.
What licences are required to set up a solvent extraction plant in India?
Hexane is a petroleum solvent, so storage needs a licence from PESO (Petroleum and Explosives Safety Organisation). You will also typically need Consent to Establish and Consent to Operate from the State Pollution Control Board, a factory licence, fire safety clearance, boiler registration and FSSAI registration for the crude oil. The exact list varies by state, so check with local authorities early in the project.
How do I decide the right capacity for a solvent extraction plant?
Start with how much seed or cake you can reliably source every year, not with the biggest plant you can afford. Divide the realistic annual supply by your expected operating days to get a tons-per-day figure, then add some margin for growth. Fostechno supplies plants from 5 to 500 TPD and can design for phased expansion, so you can start at one capacity and increase later.
Seed Preparation
Why is seed preparation so important before extraction?
Oil can only be extracted efficiently if the seed cells are opened and the solvent can flow evenly through the bed. Preparation steps such as cleaning, cracking, conditioning (cooking), flaking and sometimes expanding create thin, porous flakes with the right moisture and temperature. Poor preparation is one of the most common causes of high residual oil in meal. Learn more on our oil seed preparation page.
What does soybean dehulling achieve?
Dehulling removes the fibrous hull from soybean before flaking. This raises the protein content of the meal so it can be sold as high-protein (HiPro) meal at a better price, reduces the load on the extractor and improves extraction efficiency. The hulls can be toasted and sold separately or blended back to meet a specific meal specification.
Oleochemical & Biodiesel Plants
What does an oleochemical plant produce?
An oleochemical plant converts vegetable oils, animal fats and refinery by-products into industrial chemicals. Typical products include fatty acids (split and distilled), refined glycerine, biodiesel (fatty acid methyl esters) and hydrogenated fatty acids. These go into soaps, detergents, cosmetics, lubricants, rubber, pharmaceuticals and fuels. Explore our oleochemical plant solutions.
Which feedstocks can be used in a biodiesel plant?
Biodiesel can be produced from refined or crude vegetable oils, used cooking oil, acid oil, palm fatty acid distillate (PFAD), animal fats and non-edible oils such as jatropha and karanja. Lower-cost feedstocks usually have higher free fatty acid (FFA) and impurities, so the plant needs proper pretreatment. Matching plant design to your feedstock is the most important decision in a biodiesel project.
How does high free fatty acid (FFA) feedstock affect biodiesel production?
In standard transesterification, an alkaline catalyst reacts with free fatty acids to form soap, which lowers yield and makes separation difficult. Feedstocks with high FFA are therefore first passed through an acid esterification step that converts the FFA into methyl esters, followed by normal transesterification. This two-step route lets you use cheaper feedstocks without losing yield. See our transesterification and biodiesel page.
What quality standards must biodiesel meet?
In India, biodiesel (B100) is specified under IS 15607. For export and international projects, EN 14214 (Europe) and ASTM D6751 (USA) are the reference standards. These cover parameters such as ester content, free and total glycerine, water, acid value, methanol content and oxidation stability. Your plant’s washing, drying and methanol recovery sections must be designed to meet the standard you sell into.
Why is methanol rectification needed in a biodiesel plant?
Biodiesel production uses excess methanol to push the reaction to completion. After the reaction, this methanol ends up in both the biodiesel and glycerine phases and is mixed with water. A methanol rectification column separates it into pure, dry methanol that can be reused in the reactor. This cuts chemical cost, improves safety and keeps methanol out of the final products. Read about methanol rectification.
How much glycerine is produced as a by-product of biodiesel?
For every 10 tons of oil converted into biodiesel, roughly 1 ton of crude glycerine is produced, which is about 10% by weight. Crude glycerine contains methanol, salts, soap and water, so its market value is low. Refining it adds a second revenue stream and turns a disposal problem into a saleable product.
How is crude glycerine converted into refined or pharma-grade glycerine?
Crude glycerine is first pretreated to remove soap, fatty matter and salts, then concentrated by evaporation. It is distilled under deep vacuum and finally bleached with activated carbon to give a clear, odourless product. Depending on the design, the output can meet technical, industrial or pharmacopoeia (IP/USP) grade specifications. See our glycerine refining page.
What is high-pressure fat splitting?
Fat splitting (hydrolysis) breaks triglycerides into fatty acids and glycerine using water at high temperature and pressure in a continuous splitting column, without a catalyst. Modern columns achieve a very high degree of splitting, giving crude fatty acids for distillation and sweet water that is concentrated into crude glycerine. Learn more about fat splitting.
What is the difference between straight and fractional distillation of fatty acids?
Straight distillation purifies crude fatty acids by separating them from colour bodies, unsaponifiables and residue, giving a single distilled fatty acid product. Fractional distillation goes further and separates the fatty acid mix into individual cuts, for example lauric, myristic, palmitic or stearic-rich fractions, which sell at higher prices to specialty users. Both run under high vacuum to avoid heat damage. Read about fatty acid distillation.
Can a biodiesel or oleochemical unit be added to an existing edible oil refinery?
Yes. Edible oil refineries produce by-products such as acid oil (from soapstock splitting) and fatty acid distillate (from physical refining) that are good feedstocks for biodiesel or fatty acid production. Integrating an oleochemical unit at the same site lets you share utilities, storage and manpower and earn more from material that is otherwise sold at a discount.
Fat Modification Plants
Hydrogenation, interesterification or fractionation: which process should I choose?
It depends on the product you want to make. Hydrogenation hardens oils by saturating double bonds and is used for vanaspati and some industrial fats. Interesterification rearranges fatty acids to change melting behaviour without creating trans fats, which makes it ideal for zero-trans margarine and shortening. Dry fractionation separates oil like palm into liquid and solid parts using controlled cooling. Many specialty-fat plants use two or all three. Explore our fat modification plants.
How can trans fat be kept within FSSAI limits?
FSSAI limits trans fatty acids in edible oils and fats to a maximum of 2%. Partial hydrogenation is the main source of trans fats, so producers now rely on full hydrogenation combined with interesterification, or on blends of palm fractions and liquid oils. Careful control of deodorization temperature and time also stops trans fats forming during refining.
What catalyst is used in hydrogenation, and how is it removed?
Edible oil hydrogenation normally uses a nickel catalyst in a stirred reactor with hydrogen gas under controlled temperature and pressure. After the reaction, the catalyst is removed by filtration, and the oil usually goes through post-bleaching and deodorization to remove nickel traces and off-flavours. Good filtration and catalyst handling keep product quality high and catalyst cost under control. See our hydrogenation plant page.
What is the difference between low-pressure and high-pressure hydrogenation?
Low-pressure hydrogenation is typically used for edible oils and fats such as vanaspati and bakery fats, where the target is a specific melting point and texture. High-pressure hydrogenation is used where fuller saturation is needed, such as producing hardened fats and hydrogenated fatty acids for industrial use. The reactor, hydrogen system and safety design are different for each, so the choice must be made at the planning stage.
What is the difference between chemical and enzymatic interesterification?
Chemical interesterification uses a catalyst such as sodium methoxide and randomly rearranges fatty acids across the triglyceride. Enzymatic interesterification uses an immobilised lipase that works under milder conditions and can be more targeted, with fewer by-products and less post-treatment. Chemical systems usually have lower running costs, while enzymatic systems give cleaner products. Read more on interesterification.
What is the difference between single-stage and double-stage palm oil fractionation?
Single-stage dry fractionation splits palm oil into palm olein (liquid) and palm stearin (solid). Double-stage fractionation takes the olein through a second crystallisation to produce super olein, which stays clear at lower temperatures, and a palm mid fraction (PMF) used in confectionery fats. Double-stage plants need more crystallisers and filter capacity but produce higher-value products. See dry fractionation of palm oil.
Value Addition Plants
Which oils can be used to produce lecithin?
Lecithin is made from the gums removed during water degumming of crude oils rich in phospholipids, mainly soybean, sunflower and rapeseed oil. Sunflower lecithin is in demand as a non-GMO alternative to soy lecithin. Producing lecithin turns a refinery by-product into a food, feed and pharma ingredient. Learn about our lecithin plant.
How is liquid lecithin different from de-oiled (powder) lecithin?
Liquid lecithin is made by drying the wet gums under vacuum, usually in a thin-film dryer, to give a viscous product that still contains some oil. De-oiled lecithin goes a step further: the oil is removed with acetone, giving a powder or granules with a much higher phospholipid content. De-oiled lecithin sells at a premium for pharma, nutraceutical and instant food uses.
What equipment is used in a bakery shortening and margarine plant?
A typical line includes oil blending and dosing tanks, an emulsion tank (for margarine), a high-pressure pump, scraped surface heat exchangers for rapid chilling, pin rotor machines for kneading and crystal development, a resting tube, and filling and packing machines. Controlled tempering then stabilises the crystal structure for good creaming and shelf life. See our bakery shortening and margarine page.
What is CBS made from palm kernel oil?
CBS (cocoa butter substitute) is a lauric specialty fat made from palm kernel oil through fractionation and/or hydrogenation. It melts quickly in the mouth like cocoa butter but does not need tempering, so chocolate, compound coatings and confectionery manufacturers use it to lower cost. Learn more on CBS from palm kernel oil.
How do value-addition plants improve the profitability of an oil business?
Basic crude or refined oil is a commodity with thin margins. Value-addition plants such as lecithin, shortening, margarine, CBS and fractionated fats turn the same raw material or its by-products into specialty products sold to bakeries, confectioners and food processors at higher prices. They also reduce dependence on a single market. View all our value addition plants.
Equipment & Manufacturing
Which critical equipment does Fostechno manufacture in-house?
Fostechno has manufacturing facilities for precision fabrication of critical process equipment, including deodorizers, bleachers, crystallisers, heat exchangers, high-pressure columns, extractors, cookers, distillation columns and reactors. Making this equipment in-house gives us control over quality, delivery schedules and design changes during the project.
How is equipment quality checked before dispatch?
Along with our internal quality checks, we work with a third-party inspection agency that carries out stage-wise inspection of equipment made at our works, so it meets international standards. Inspection reports give clients and their lenders written proof of quality before the equipment leaves the factory.
Can Fostechno supply individual equipment instead of a complete plant?
Yes. Along with full turnkey plants, we design and manufacture individual process equipment and sections, for example a deodorizer, bleacher, extractor, crystalliser or distillation column, for new lines or to replace and upgrade equipment in existing plants. Share your current process details and we will recommend equipment that fits your line.
Working with Fostechno
What is the difference between EPC and EPCC?
EPC stands for Engineering, Procurement and Construction: the contractor designs the plant, sources equipment and builds it. EPCC adds Commissioning: the contractor also starts up the plant, runs performance trials and hands it over in running condition. Fostechno undertakes both EPC and EPCC projects, so you can choose how much responsibility you want a single partner to carry.
What information should I share to get an accurate quotation?
To prepare a realistic proposal, we need your raw material (seed, cake or oil type), required capacity in TPD, the end products and quality you want, site location and available land, utilities available (power, water, steam fuel), whether you need EPC or EPCC scope, and your target timeline. The more detail you share, the more accurate the cost and layout we can give you. Talk to us to start.
Does Fostechno execute projects outside India?
Yes. Fostechno serves clients in India, Bangladesh, Uzbekistan and other international markets. For overseas projects, we handle engineering, equipment manufacturing and supply, and provide technical teams for erection supervision, commissioning and after-sales support. Learn about our worldwide turnkey edible oil plant solutions.
Can Fostechno expand, upgrade or modernise an existing plant?
Yes. Our services include process optimisation, technical consultation, and automation and integration, so we can study your existing line and recommend capacity expansion, energy saving, yield improvement or product upgrades. Upgrades are often the fastest way to improve margins without building a new plant.
What does Fostechno’s performance guarantee cover?
Fostechno offers performance guarantees on its plants, with parameters agreed in the contract for each project. These typically cover areas such as processing capacity, product quality and key consumption figures. Because parameters depend on your raw material and scope, they are defined clearly in the proposal before the order is placed.
Which companies have worked with Fostechno?
Our clients include Shree Basant Oil, B.L. Agro Ltd., Ajanta Industries, Amrit Oils, Adani, AWL Agro, Meghna Group, KS Oil, Khanda Biofuels, Geo Fresh Ltd., Sunbridge, BN Agritech and others across India and abroad. See our full client list.
How can I contact Fostechno, and how quickly will I get a response?
Call or WhatsApp +91 9696177472, email info@fostechnos.com, or visit us at Dwarka Sector 6 & 10 Market, New Delhi 110075. Our team is available Monday to Saturday, 9 AM to 6 PM IST, and we respond to enquiries within 24 hours. You can also use our contact page.
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Still have a question that is not answered here? Our oil technologists and chemical, mechanical, electrical and instrumentation engineers are ready to help you plan your solvent extraction, oleochemical, fat modification or value-addition project. Talk to our experts today.
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