Olive cake

Olive cake is a product of the second extraction of the olive oil. First extraction is done on the  olive oil factories by mechanical squeezing of the olives. As a result of it  so called virgin olive oil is received. After extraction the brown mass called pommace  with the moisture about 60% and oil content about 7-8%  in the most of the cases transported to special factories where the second extraction by hexane is performed from the raw material . As a result  of this process  the second extraction oil is produced and the residue consisting of olive meat, olive skins and whole and crushed olive stones with the moisture about 13-14% is received. 

 

This matter is called olive cake and is an ideal biofuel. In the most of the cases olive stones are separated from the olive cake often by centrifugation, but after this procedure there are still about  30% of the crushed olive stones left in the material.

For several years starting from 2001 olive cake  was widely  used in Belgium, UK and later in Poland for co firing with coal. Usually about 4-7% of olive cake was admixed to coal.  It can be successfully used in biomass dedicated power plans as a single fuel or in combination with other products.

        

                    

                                           olive cake stockpile                                                                              sampling

Olive cake has a moisture about 13-14%,ash content about 6-7% and NCV about 15,5-16,5 GJ per mt (sometimes up to 17,0).Oil content is usually abt 1,5%.Oil content should not be more than 4%.Combination of moisture and oil in the biomass cargo over 20% ( for example 16% of moisture and 4% of oil) is regarded to be dangerous for transportation as it can cause an auto combustion.Another important exporter of olive cake is Tunisia.Tunisian olive cake usually has much less smell than the Spanish one,it consist of much smaller particles reminding powder.

Our experience of trading olive cake have shown  that it is important to sieve Tunisian  olive cake before loading. Our suppliers are using a special system for to sieve the olive cake. By using this equipment the particles with the size over 4 mm  mostly containing small stones , small olive tree branches, some other rubbish are separated from the cargo. Use of the sieve with the diameter of 1 mm helps to separate the sand.

 

                                      screener                                                                    screening with 0,75mm

 

              waste material after screen with 4mm                                          olive cake after screening

Very important is to monitor the temperature of the olive cake when it is kept  over summer time under the open sky and also in closed storages. Temperature over 60 degr C have to be regarded as too high for loading. Any cargo with high temperature have to be turned around by buldosers and cooled down before loading on board of the vessel. Closed  storages have to be properly ventilated  as carbon monoxide can be present.

Loading and unloading of olive cake in the harbours which are located close to residential  areas is not recommended because of the smell  (especially the Spanish product) and dust coming from the cargo.

 

 

Olive cake is a crop material. Some years the crop can be very good, some years – very poor .It is difficult to plan big quantities of olive cake for several year contracts.

Crop usually starts in December-January and ends up in  March- April. But it is possible to perform olive cake deliveries during  summer as well , as the product can be kept in the second extraction plants.