Integrated Optimization for the Coupling Network of Refinery and Synthetic Plant of Chemicals

Synthetic plant of chemicals (SPC) consumes large amounts of hydrogen and carbon-oxides while refineries require high-purity hydrogen. Coal gasification (CG) and steam methane reforming (SMR) are common industrial hydrogen production technologies. Their gas products are essentially a mixture of H2, CO, and CO2. Therefore, such gas products can provide both syngas for SPC and concentrated hydrogen for refinery through appropriate allocation. Based on the composition complementation of gas products from CG and SMR for their efficient utilization, this paper proposed an integration methodology for refinery and SPC coupling networks to conserve both fossil fuel resources and carbon emissions. A superstructure is established as a problem illustration and a nonlinear programming model (NLP) is formulated as a mathematical solution. A case study is performed, and the results show that the coupling network integration can save 19.1% and 20.2% of coal and natural gas consumption, as well as corresponding carbon emission and operation costs.

Ru-promoted perovskites as effective redox catalysts for CO2 splitting and methane partial oxidation in a cyclic redox scheme

The current study reports A_xA'_1-xB_yB'_1-yO_3-δ perovskite redox catalysts (RCs) for CO₂-splitting and methane partial oxidation (POx) in a cyclic redox scheme. Strontium (Sr) and iron (Fe) were chosen as A and B site elements with A' being lanthanum (La), samarium (Sm) or yttrium (Y), and B' being manganese (Mn) or titanium (Ti) to tailor their equilibrium oxygen partial pressures (P_O2s) for CO₂-splitting and methane partial oxidation. DFT calculations were performed for predictive optimization of the oxide materials whereas experimental investigation confirmed the DFT-predicted redox performance. The redox kinetics of the RCs improved significantly by 1 wt% ruthenium (Ru) impregnation without affecting their redox thermodynamics. Ru-impregnated LaFe_0.375Mn_0.625O₃ (A = 0, A' = La, B = Fe, and B' = Mn) was the most promising RC in terms of its superior redox performance (CH₄/CO₂ conversion >90% and CO selectivity ∼95%) at 800 °C. Long-term redox testing over Ru-impregnated LaFe_0.375Mn_0.625O₃ indicated a stable performance during the first 30 cycles followed by an ∼25% decrease in the activity during the last 70 cycles. Air treatment was effective to reactivate the redox catalyst. Detailed characterizations revealed the underlying mechanism of the redox catalyst deactivation and reactivation. This study not only validated a DFT-guided mixed oxide design strategy for CO₂ utilization but also provides potentially effective approaches to enhance redox kinetics and long-term redox catalyst performance.

Chemical Looping Technology: Oxygen Carrier Characteristics

Chemical looping processes are characterized as promising carbonaceous fuel conversion technologies with the advantages of manageable CO2 capture and high energy conversion efficiency. Depending on the chemical looping reaction products generated, chemical looping technologies generally can be grouped into two types: chemical looping full oxidation (CLFO) and chemical looping partial oxidation (CLPO). In CLFO, carbonaceous fuels are fully oxidized to CO2 and H2O, as typically represented by chemical looping combustion with electricity as the primary product. In CLPO, however, carbonaceous fuels are partially oxidized, as typically represented by chemical looping gasification with syngas or hydrogen as the primary product. Both CLFO and CLPO share similar operational features; however, the optimum process configurations and the specific oxygen carriers used between them can vary significantly. Progress in both CLFO and CLPO is reviewed and analyzed with specific focus on oxygen carrier developments that characterize these technologies.

Chemical looping beyond combustion: production of synthesis gas via chemical looping partial oxidation of methane

Systematic development of Fe–Ni bimetallic carrier results in efficient and safe chemical looping process for methane partial oxidation to syngas.