THE SYNPET SOLAR RECEIVER REACTOR
The reactor chamber is a cylindrical cavity made of S30815 (ASTM) / 1.4835 (EN) heat-resistant steal that contains a windowed aperture. Manufacture of the solar-receiver started at the beginning of this year following the design of ETH [1]. The cavity-receiver has been divided into four segments for assembly reasons. Fig. 1 shows the pre-assembled solar-receiver at PSA installations.
An insulation liner is included to protect the steel housing from the very high temperature inside the reactor, this insulation is able to withstand up to 1400 °С. The liner is fabricated with a studied combination of two types of ceramic materials based on Al2O3 (89 to 95 % Al2O3). Additional insulation will be applied at the outside of the reactor.
The feedstock (slurry) is injected into the reactor’s cavity via a tangential inlet port located near the window. The window is actively cooled and kept clear from particles and/or combustibles gases by means of an aerodynamic protection curtain created by a tangential flow of steam through four tangential nozzles located at the conical part of the aperture.
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The most important features regarding the receiver reactor are related to the injection of the coke slurry (without using a inert gas) and the reactor window.
One of the most important issues of this study has been to design an efficient injection system with regard to their availability to fluidise reactants into the cavity without the need of a carrier gas. The mode of conveyance of the material and the gasifying medium, in traditional gasification, is presented by general categories of: fixed-bed, fluidised-bed and entrained-bed reactors. In particular, in the entrained flow gasifier, coal and other solid fuel particles concurrently react with steam and air in suspension fluid flow mode. The full entrainment of the particles requires relatively high gas velocities and these lead to high throughputs and residence times of only a few seconds.
For this cavity reactor, an entrained flow has been simulated. An innovative concept using a combined slurry / pneumatic transport system was used. The pulverized coke is mixed with the (liquid) reactant water that is subsequently evaporated to create a high-speed “pneumatic” injection. The feasibility of this concept was stu
demonstrated in the 5 kW solar reactor at PSI [3]. This system allows to fluidize particles up to 100 microns without the need of a carrier gas. Inside the cavity, the mixture forms a flow that progresses towards the rear path and exit the cavity via an axial outlet port located at the back of the cavity.
On the second hand, up scaling of the reactor quartz window with a diameter of 1400 mm is of particular challenge. To find out the real limits of this window, a comprehensive finite elements calculation has been performed.
