Press tests with Jatropha seeds were conducted at the Pilot Pflanzenöltechnologie e.V. Magdeburg. Different seeds from South East Asia (India, Laos, and Vietnam) were pressed on a Komet Monforts S87G oil press. The maximum temperature of the produced oil was around 95 C.

Hot press operation. The heating elements in the upper part heat the press to a hot temperature level. 

The degree of oil recovery differs between the utilized Jatropha seeds in a range of 81 – 87%. Therefore, the oil content of the press cake was around 7.5 – 9.5%. The amount of solid material was quite high in all pressed seeds and ranged between 10 to 13 %. Normally the amount of solid material should be around 2-4%. In total that means an oil production rate of approximately 24.2 – 30.3%. Therefore, it can be said that for one liter of oil, 3.5 kilogram of seeds are necessary.

Good oil recovery rate and a press cake with a solid structure and less oil content. 

The analyses were conducted through Oehmi Analytik.
The phosphorus content differs through a wide range in the utilized material. According to the DIN standard V 51605, there is just 12 ppm of phosphorus allowed. The chemical analysis showed values between 16 and 180 ppm. According to these results, it is difficult to reach the DIN standard for plant oil with hot pressing operation. Therefore, a further treatment of the oil like refining or transesterification might be necessary if the biofuel is utilized in modified diesel engines. Moreover the huge differences between the used seed material shows that the storage and harvest conditions are important. If the seeds are stored under bad conditions or the seed material is infected by insects or mushrooms, the phosphorus content increases dramatically.

The acid value also differs in a wide range from 3 to 18. Compared to the DIN standard which only allows a value lower than 2, this was too high and a further treatment of the oil is recommended. Moreover, the fatty acid spectrum was analyzed and surprisingly it did not differ much to the different seed material.

Further studies should be undertaken for verifying these results with other seed material and different press parameters. 

Jakob Rietzler

Sunlabob