Caparroso biodiesel plant in Navarra (Spain).

Spain is one of the largest growth markets for energy from renewable resources. Consumption of primary energy has risen substantially in recent years and the emission of greenhouse gases increased by around 35 percent. The Kyoto Protocol only permits Spain emission increases of 15 percent until

To counter this trend Spain's government is placing very strong emphasis on regenerative energy sources. The 'Plan de Fomento de las Energias Renovables en Espana' specifies ambitious targets such as doubling the share of regenerative sources of energy in primary energy consumption by the year 2010.

The Kyoto Protocol

The Kyoto Protocol--the United Nations framework convention on climate changes--specifies the introduction of biofuels to the transport fuel market to reduce the emission of greenhouse gases. The EU Directive relating to the "promotion of biofuels' targets an increase in the market share of biofuels in transport fuels from 2% in 2005 to 5-75% in the year 2010.

Spain's first biodiesel plant

Lurgi built a plant for the production of biodiesel/FAME and pharmaceutical-grade glycerin with an annual capacity of 35,000 tons of biodiesel/FAME for its customer Energia Hidroelectrica de Navarra (EHN) in Caparroso, Navarra. This plant went on stream in April this year after a construction time of around one year and a half. The quality of the biodiesel complies with EN 14214, that of the pharmaceutical-grade glycerin to European/US Pharmacopeia 99.5. As plant feedstock all vegetable oils, in particular from rape seed, palm olein, sunflower seed and soy beans are used and have been proven in operation. Lurgi built this plant under a turnkey contract. The biodiesel plant includes the units for bleaching, chemical neutralization, winterization, transesterification through to the crude glycerin and pharmaceutical-grade glycerin.

The Lurgi biodiesel process

The Lurgi biodiesel process centers around the transesterification of different raw materials to methyl ester using methanol.

Transesterification is based on the chemical reaction of triglycerides with methanol to methyl ester and glycerin in the presence of an alkaline catalyst. The reaction takes place in 'mixer-settler units' whereby the actual conversion occurs in the mixers and the separation of methyl ester as the light phase and glycerin water as the heavy phase in the settlers on account of the insolubility of both products. The byproduct components are removed from the methyl ester in the downstream washing stage operated in counter-current. After a final drying the biodiesel is ready for use. Any residual methanol contained in the glycerin water is removed in a rectification column. Here, the methanol reaches a condition and purity that make it suitable for recycling to the process. For further cleaning of the glycerin water optional steps are available such as chemical treatment, evaporation, distillation and bleaching. This continuous process ensures constantly high product quality and low catalyst consumption. Also, the process can be easily controlled and guarantees high conversion and yield rates.

Raw materials

In principle, most edible oils and fats--from both vegetable and animal sources--can be transesterified; fatty acids, in contrast, can be esterified or re-esterified with glycerine. In view of the properties required for fuel applications, precleaned oils from rape seed and sunflower seed are preferably used in Europe.

Plants for a clean future

Lurgi has been building biodiesel plants for 20 years and takes a leading role in the development of plants that meet the industry's demand for higher capacities, improved plant economics and product quality.

Lurgi AG

Lurgiallee 5

60295 Frankfurt/Germany

Phone + 49 69 5808-0

Fax + 49 69 5808-3888

Email: kommunikation@lurgi.de

Web: www.lurgi.com