La Pereda 1.7 MWth pilot plant
La Pereda 1.7 MWth pilot plant is integrated with La Pereda Power plant located in the North of Spain. This facility was built and commissioned in 2011 under the frame of the FP7 project CaOling. This facility is the largest pilot plant aimed to demonstrate the standard Calcium Looping configuration based on circulating fluidized bed reactors. This experimental facility is integrated with a commercial CFBC power plant with an install capacity of 50 MWe. The pilot is composed by two interconnected CFB refractory lined reactors with a height of 15 m and with internal diameters of 0.75 m (calciner) and 0.65 m (carbonator). The pilot has been designed to operate in a wide range of operation conditions. Each reactor is equipped with a loop seal that allows controlling the solid circulation between reactors when operating at different gas velocities by diverting the stream of solids coming from the stand pipe to the same reactor (internal circulation) or to the opposite reactor.
The flue gas fed to the carbonator is taken from the power plant after the electrostatic precipitator using a fan. The carbonator is equipped with removable cooling bayonet tubes which allow variable heat extraction from the reactor under different conditions of temperature, solid circulation flows and different intensity of the exothermic carbonation reaction. The calciner is able to operate under air combustion or under oxy-fuel combustion conditions, using O2 and CO2 coming from tanks of liquefied gases. There is a continuous limestone and coal feeding system connected to the calciner, which allows working in a steady state combustion and sorbent feeding modes. There is also a continuous solid removal system in the calciner made up with a water-cooled screw feeder. The capability of this pilot plant has been demonstrated by more than 2600 h of operation under different experimental conditions through several European projects (CaOling, ReCaL, CaO2).
The USTUTT’s 230 kWth pilot scale fluidized bed plant was built from 2007-2010 within a joint industrial project of USTUTT and EnBW Utility. The aim of the project was to demonstrate the Calcium Looping CO2 capture process under industrial conditions.The pilot plant consists of three refractory lined reactors: one calciner and two carbonators. These reactors can be coupled to each other offering two different configuration options. One configuration with a CFB carbonator and a CFB calciner and another configuration consisting of a TFB carbonator and a CFB calciner, which are connected to each other by means of a bottom interlink. This latter configuration is the one to be used in FlexiCaL.
Experimental investigations during FlexiCaL
USTUTT will investigate a reactor configuration based on a TFB-CFB system. In this configuration, the calciner is an oxygen fired CFB combustor, which provides the possibility to investigate the impact of oxy-fuel calcination with flue gas recirculation. Flue gas supply to the TFB carbonator can be realized by means of either a coal combustor or a synthetically mixed flue gas, enabling to simulate flue gas concentrations of coal fired power plants, gas fired power plants or cement plants.
The TFB-CFB reactor configuration enables a flexible flue gas load in the carbonator, detached from the circulation of sorbent between the reactors in different fluidization regimes: from bubbling over turbulent near to circulating conditions.
This configuration is unique for Calcium Looping pilot plants in the world and contributes to the increasing demand for flexible CCS technologies, being also considered as one key solution for this issue.