Demo 3 – RAR

Process: Boiling and sugar crystallization

Site: Porto

Country: Portugal

Longitude: 08º38’44’’W

Latitude: 41º10’23’’N

DNI: 1667 kWh/m2

Space opportunities: a 40 m x 100 m ground space is available for the installation of a solar system.

Description of the industrial process and current control

RAR Açúcar is a company dedicated to the refining and selling of sugar. It was established in Oporto in 1962 following the merger of nine small sugar refinery units from the northern region of Portugal. The concentration of activities into one single production unit, together with ongoing investments in technology, has allowed the company to increase its production capacity and efficiency.

The plant uses fuel oil and natural gas as fuel both for the cogeneration of power and heat in a counter-pressure turbine and for the production of steam in dedicated boilers. Out of the overall fuel consumption, natural gas accounts for 37% and fuel oil for 63%.

The current installation consists of 3 boilers, fed with natural gas and heavy fuel oil. Also, there is a counter pressure turbine, having a nominal electricity production of 3 MW through the expansion of steam at 1 bar and 125°C. Finally, one gas turbine of 5 MWel and a waste heat boiler of 10 t/h at 400°C and 24 bar. The steam used in the sugar process is all at a pressure of 1 bar and 125ºC. The crystallization process accounts for a significant part of the total heat demand of the plant.

SHIP project to be implemented

  • Linear Fresnel with vacuum receiver – direct steam generation system

  • Heat Transfer Fluid: Saturated Steam

  • Net Aperture Area: 690 m2

  • Gross Area: 926 m2

  • Peak power: 415 kW

  • Gross heat production per year: 448 MWhth

  • Number of modules: 30

  • Yearly global efficiency: 40%

  • CO2 savings: 143.7 tCO2eq

  • Solar fraction: 4% average for cristallization, 76% thermal demand during weekends

  • Annual sugar production increase: 1%

  • Heating cost: 2,92 c€/kWh

  • Expected payback: 10 year