Annual Report 2006 - Plataforma Solar de Almería

PLATAFORMA SOLAR DE ALMERÍA
Solar gasification of coke without combustion can be represented in a simplified
by the reaction:
⎛x
⎞
CHxOy + ( 1− y)
H2O = ⎜ + 1− y H2
+ CO
2
⎟
⎝ ⎠
(1)
Gasification of 1 mol of C requires approximately 1 mol of C as the source
of energy supply. That is why substitution of fossil energy by solar energy
supply reduces CO 2 emissions by about 50%.
Purpose: The main purpose of the SYPET project is to develop a specific solar
gasification process for coke and waste from extra-heavy oil processing in
the Faja del Orinoco. The development is specifically finding the thermodynamic
and kinetic parameters of associated reactions, and selection of particle
sizes and residence times, design of a solar reactor with a quartz window and
its scale-up and testing in a 500 kW installation located at the top of the PSA
CRS tower.
Results achieved in 2006: After demonstrating the technical feasibility of
the process in previous years, in 2006, testing concentrated on selecting the
optimum coke particle size to be gasified and testing a method of injecting
the material. Finally, it was decided to feed a slurry of coke particles and water.
The practical advantages of using a slurry are asociated with eaier transport
and injection of the solid reagent and with system scale-up. In 2006,
experimental testing was done using a petcoke slurry feedstock. Figure 3.23
shows the effect of particle size and stoichiometry of the slurry on chemical
conversion. A higher H 2 O/C in the slurry favors reaction kinetics, but at the
cost of higher flow rates and lower residence times, resulting in lower conversion
rates. The mean conversion achieved was 48% and the maximum was
87%, using particles with diameters of less than 80 μm.
The results have served to complete the design and construct a 500-kW
reactor, as well as for preheating system and heat rejection definition. The
Synpet-500 facility will be erected and tested at the PSA in 2007.
Publication: [3.23][3.24][3.25][3.26][3.27]
Figure 3.23 Chemical conversion of petcoke and energy efficiency of the conversion
in solar tests in order by particle size and stochiometry of the slurry.
58