January 29, 2019

It has always been the case that Oil Expellers® made by Anderson International work on oil seeds, but Vincent screw presses do not. Typical applications for the Anderson machines are canola and rapeseed, sunflower seeds, corn germ, groundnuts (peanuts), and copra (dried coconut meat).

It took a new engineer who was not handicapped by this knowledge to run some pecans in our press. The result was a notable success, as can be seen in this YouTube video:

3 minutes PECAN OIL
https://www.youtube.com/watch?v=7GutbMJ37Ns

The video shows that scrap and surplus pecans give up a steady flow of oil when run through our small presses. 50% yield is typical. This is achieved without the conventional process of heating and flaking the nuts before they are fed into the press.

This success led to a trial with hazelnuts. The results were equally spectacular, as can be seen in this video:

5 minutes HAZELNUT OIL EXTRACTION
https://www.youtube.com/watch?v=CHNrXr_ICdw&feature=youtu.be

Throughput capacity in the CP-4 laboratory press was a solid 100 pounds hour. Even at this rate, oil extraction ran 55% by weight.

To achieve these results, much greater pressure is required on the discharge cone than we are used to. The quick remedy has been to use a Pressure Multiplier (see Pressing News #304). This provides up to double the normal plant air pressure, at the expense of consumption of compressed air. For a new press being built, we are simply installing an air cylinder with a larger piston diameter.

Pretty much standard screws work well in this new application. However work is still underway to find the optimum screen configuration. The need for finer filtration and greater burst strength has steered us toward wedgewire screens with narrow slots. We started with the 0.010″ slots we use on alcohol presses, and we have worked our way down to testing 0.004″ slots.

At the same time we have been working with perforated screens. Here we have gone to electron beam drilled holes, using Monel instead of the normal 304 stainless. Holes with diameters as small at 0.006″ have been trialed.

This application represents a small niche market. After all, when was the last time you bought a bottle of almond or hazelnut oil?

Issue #311