Design of a 1 MWth Pilot Plant for Chemical Looping Gasification of Biogenic Residues

Abstract

Chemical looping gasification (CLG) is a promising process for the thermochemical solid to liquid conversion route using lattice oxygen, provided by a solid oxygen carrier material, to produce a nitrogen free synthesis gas. Recent advances in lab-scale experiments show that CLG with biomass has the possibility to produce a carbon neutral synthesis gas. However, all experiments have been conducted in externally heated units, not enabling autothermal operation. In this study, the modification of an existing pilot plant for demonstrating autothermal operation of CLG is described. Energy and mass balances are calculated using a validated chemical looping combustion process model extended for biomass gasification. Based on six operational cases, adaptations of the pilot plant are designed and changes discussed. A reactor configuration using two circulating fluidized bed reactors with internal solid circulation in the air reactor is proposed and a suitable operating strategy devised. The resulting experimental unit enables a reasonable range of operational parameters within restrictions imposed from autothermal operation.

Effect of the Mass Conversion Degree of an Oxygen Carrier on Char Conversion and Its Implication for Chemical Looping Gasification

“… 6 Marx et al. 7 pointed out that the cost-saving advantage of a dual-bed gasifier like CLG is the elimination of the air separation unit (ASU), which requires a lot of energy supply and high capital and operational costs. 8 …”

“…A simple process analysis predicted a high suitability of CLG for syngas production with a carbon capture process . Marx et al . pointed out that the cost-saving advantage of a dual-bed gasifier like CLG is the elimination of the air separation unit (ASU), which requires a lot of energy supply and high capital and operational costs …”

Process Analysis of Chemical Looping Gasification of Biomass for Fischer–Tropsch Crude Production with Net-Negative CO2 Emissions: Part 1

“…Here, the 1 MW th CLC pilot plant in Technischen Universität Darmstadt (TU Darmstadt) is used as the best reference, where the CLC unit was modified and operated for CLG experiments with biomass . This pilot plant is a 1 MW th unit with a total bed inventory of 1000 kg with 80 kg of bed material in the FR . The reported solids circulation is around 7000–7500 kg/h at the FR outlet, corresponding to a ratio of 1.94–2.08 kg of OC/MW th .…”

Chemical Looping Combustion and Gasification: A Review and a Focus on European Research Projects

“…214,249−254 Depending on the fluidization regimes in the two vessels (bubbling, turbulent, riser), different design details are adopted, 214,249−254 up to the kW th -scale (25 kWth, 249 10 kWth, 250 1.5 kWth, 253,254 0.3 kWth 252 ) and the MW th -scale in a recently presented BCLG pilot plant. 255,230 In the continuous CLG operation by DIFB, the OC circulation is responsible for both the transport of heat and the transport of oxygen. 215,256 Samproń et al 256 stated that usually the control of oxygen in the FR takes place by changing the amount of fuel fed to FR and keeping the solid circulation rate constant; in such a way, the ratio between OC and fuel holdups in the FR becomes lower than that of equivalent CLC, achieving partially oxidizing conditions.…”

“…The literature generally reports of DIFB as the most popular reactor configuration to continuously convert solid fuels by CLG, having the same rationale described for CLC (Figure (a)): the solid OC particles circulate between a FR (hosting gasification by OC reduction) and an AR (combustion, OC oxidation); regenerated OC particles bring in the FR part of the heat of combustion from the AR as specific heat; the undiluted syngas leaves the FR. ,− Depending on the fluidization regimes in the two vessels (bubbling, turbulent, riser), different design details are adopted, ,− up to the kW th -scale (25 kWth, 10 kWth, 1.5 kWth, , 0.3 kWth) and the MW th -scale in a recently presented BCLG pilot plant. , …”