Dimensioning Air Reactor and Fuel Reactor of a Pressurized Chemical Looping Combustor to Be Coupled to a Gas Turbine: Part 1, the Air Reactor

Abstract

This paper provides a simple methodology for the design of the air reactor of a chemical looping combustor to optimize its characteristics when it is employed connected to a turbo expander to produce power. The design process, given a certain objective (e.g., electric power) defines the reactor specifics, namely height and diameter, taking into account the following aspects: solids inventory of the air reactor; gas velocity; air reactor transport disengaging height (TDH); solids concentration profile along the reactor height, dense bed height; freeboard height; pressure drop depending on air reactor injectors design and configuration. The total air reactor height was about 9.5 m, while the diameter was about 1.8 m. The total inventory was about 10,880 kg; while the circulation rate in the air reactor was about 110 kg/s. The operating pressure and temperature were, respectively, 12 bar and 1200 °C. The average velocity of the gases inside the reactor was about 4 m/s. The fluidization regime resulted to be comprised between turbulent and fast fluidization. Further work must be directed into the estimate of the pressure drop of the reactor, which will affect the plant efficiency in a considerable way.

Dimensioning Air Reactor and Fuel Reactor of a Pressurized CLC Plant to Be Coupled to a Gas Turbine: Part 2, the Fuel Reactor

“…This value is referred to the power of the fuel fed into the reactor so to convert it in total kilograms we need to know the efficiency of the plant, assuming a 30% efficiency we obtain a total inventory for the fuel reactor of 1360 kg. This is reasonable when compared to our value because in [30], we have already noted that the calculated value is a theoretical one which, in practice, has to be multiplied for a safety factor that ranges between 2 and 10 times. As it can be seen in Figure 5, the inventory is calculated based on three main parameters:…”

“…The final inventory calculated in this way is about 8000 kg of oxygen carrier. This is less than the inventory required for the air reactor and indicated in [30]. If we consider the value of inventory reported for the fuel reactor in [39] this is about 34 kg/MW with syngas composed of 45 vol% CO, 30 vol% H 2 , 10 vol% CO 2 , and 15 vol% H 2 O and operating at a pressure of 20 bar and at a temperature of 1223 K, also assuming that water gas shift occurs.…”

“…The methodology followed for the design of the fuel reactor is similar to that used for the air reactor, presented in [30] and adapted from [31,32]; see Figure 3. We see in Figure 3 that the design process is divided into two parts:…”

“…To optimize the efficiency of the plant, an ASPEN Plus model has been realized in this paper we present the results of the design phase of the fuel reactor, while in [30], the results of the design phase of the air reactor is presented. We leave out of the analysis the cyclone, which is an important component and needs to be analyzed.…”

“…On the other hand, the inventory of the fuel reactor is different from that of the air reactor, even though they are both calculated in the same way as conducted in [30]. The entire process is explained in Figure 5.…”