November 11, 2020

Over one hundred and eighty KP-6, KP-10 and KP-16 presses have been sold for processing eggshells. A new model, the KP-12, developed as a specialty for eggshells, has proven a popular addition to our product line.

Frequently we get requests for operating data. Here are some of the questions and answers:

WAS MEASURING OF THE HUMIDITY/MOISTURE CONTENT AT THE OUTLET OF THE PRESS CONDUCTED?
Yes. It ranges from 16-20% moisture.

WHAT IS THE PROPORTION OF THE SOLID/LIQUID FRACTION AT THE OUTLET OF THE PRESS?
What comes out of the press as press cake is no more than 10% of the volume going into the press.

WHAT DO CLIENTS DO WITH THE LIQUID FRACTION?
Most clients either dry the liquid or sell the liquid to a company that dries it into an egg powder for animal feed. Some send it to biogas digesters, others supply it to mink farmers, and some even send it down the drain.

WHAT DO CLIENTS DO WITH THE PRESS CAKE?
Drying the shell is currently less common, but some companies do. It can be used, instead of oyster shells, as a feed supplement for the chickens. Also, the shell can be used in road beds, land applied for calcium, put into horse arenas and stalls, mixed in with chicken manure, or simply bagged and put into the dumpster.

DO THE SCREENS OFTEN “BALL UP”?
No. We specify wedgewire screens, which don’t do that. And these wedgewire screens are reversible for double life.

WHAT IS THE SCREEN SIZE USED ON THIS RAW MATERIAL?
Slots in the wedgewire screen are 0.008-0.010″ wide.

WHAT IS THE MINIMAL VOLUME OF INITIAL RAW MATERIALS NEEDED TO INSTALL A KP-10?
550 gallons per hour of whole egg or shell from a breaking plant doing 350 cases per hour (@ 360 eggs per case). This is 50% of its rated capacity.

DID YOU CALCULATE THE ECONOMIC EFFECT WHILE USING THE PRESS IN THIS APPLICATION?
Some of our customers went from paying US$8 per barrel for disposal to being paid $8 per barrel. That is a $16 per barrel swing. If you dry the egg, every five pounds of egg liquid produces about one pound of egg powder. Egg powder now sells for well over US$1.00 per pound.

WHAT ARE THE MAINTENANCE REQUIREMENTS FOR THE PRESS?
Eggshells are very abrasive. The most common maintenance is having Vincent refurbish worn screws. We use hardsurfacing on the screws that is made of tungsten carbide in a matrix. It is applied in a two stage process using powder-puddle welding.

The screens are made of Nitronic 32, which has greater abrasion resistance than 304 stainless steel. We further protected the screen by increasing the screw-to-screen clearance. The mat layer which forms protects the screen and serves as a filter to keep eggshell fines out of the press liquor.

Other newsletters on this same subject are:
May 1998 – #77 EGG SHELLS – https://www.vincentcorp.com/content/egg-shells
April 2011 – #232 EGG SHELLS UPDATE – https://www.vincentcorp.com/content/egg-shell-update/

A good video on our YouTube Channel:
5 minutes – INEDIBLE EGG SEPARATION – https://youtu.be/rafS0CONtWI

ISSUE #321