Tallow Press Product

Overview

The tallow press is a downstream piece of equipment in the rendering process. After Rendering Cooker separates fat by thermal treatment, the cooked solids cake still contains 5–15% residual fat held by capillary forces and incomplete separation. The Tallow Press applies mechanical pressure to squeeze additional fat from the cake, recovering additional product and improving the dryness of the final protein meal.

Two designs exist: screw presses (continuous) and hydraulic presses (batch). Both are effective; screw is more common in high-throughput facilities.

Screw press operation

The Press Screw is an auger with variable pitch and hardened flights. As material is fed through the Feed Hopper, the rotating screw compresses it against the Press Cage—a hardened barrel with perforations (3–5 mm slots). Pressure builds progressively along the screw. Fat, being liquid at 60–80°C, is forced through the perforations; solids are compacted and discharged at the tail.

A tallow-press-choke-ring equivalent (or variable pitch design) maintains back pressure. Motor speed and feed rate are adjusted to optimize extraction—too fast yields wet cake and poor fat separation; too slow overheats the material and increases oxidation.

Fat recovery

Fat forced through the cage perforations drains into the Fat Recovery System pan below. A Fat Screen removes solids and tissue fragments. The fat spout feeds to storage or further refining.

Recovery efficiency is typically 60–75% of the residual fat in the input cake. The remaining 25–40% stays in the pressed cake due to capillary retention and mechanical limitations.

Cake discharge and cooling

The Cake Discharge System end ejects dry, compacted cake onto a Discharge Chute or conveyor. The cake emerges hot (60–80°C) and must be cooled before grinding and storage to prevent fat oxidation. A simple air-cooling conveyor reduces temperature to 35–40°C.

Final moisture in pressed cake is typically 8–15%, acceptable for animal feed storage.

Hydraulic press variant

Some facilities use batch Tallow Press units with Hydraulic Pump and Hydraulic Cylinder. A fixed volume of cake is loaded into a chamber; the hydraulic press applies 100–300 bar for a hold time (5–15 minutes), then retracts. Fat drains during the dwell; cake is ejected manually or by plunger.

Batch presses are slower (1–5 tons/day per unit) but simpler and lower-cost for small facilities. Screw presses handle 10–50 tons/day and are preferred for larger operations.

Thermal management

The cake enters the press at 60–80°C from the cooker. Friction in the screw or cylinder raises temperature further. Excessive heat (> 90°C) oxidizes fat and damages protein meal value. Temperature is monitored by a Temperature Sensor probe and controlled by adjusting feed rate or screw speed.

Integration with rendering

The Tallow Press is typically positioned immediately downstream of the Rendering Cooker, receiving hot cake directly via insulated conveyor. The recovered fat joins the main tallow stream for storage or refining. The dried cake proceeds to grinding, sacking, and shipment as animal feed.

In integrated rendering facilities with Feather Hydrolyzer and Blood Coagulator/Dryer, the tallow press handles the by-product cake from rendering, maximizing fat recovery before final protein product preparation.

Economics

The additional fat recovered by pressing is economically valuable—tallow commands commodity pricing (typically €300–€600/ton depending on quality and market). For a 5-ton/h rendering facility, a press recovering 2–3% additional tallow represents €30–€50 additional daily revenue.

Capital cost of a screw press is €50k–€150k; a hydraulic press is €20k–€50k. Payback is typically 1–3 years for high-throughput facilities.

Maintenance and wear

The Press Cage and Press Screw wear due to abrasion and corrosion. Cage replacement costs €5k–€20k and is needed every 3–5 years. The screw may be re-hardened or replaced. Regular maintenance—lubrication of bearings, cage inspection—extends life.

Environmental considerations

The pressed cake is nearly completely dried and stabilized, reducing microbial growth and odor. Disposal or use as animal feed presents minimal environmental risk. The pressed fat is stable and can be stored long-term, reducing waste.