CO2 capture and peak shaving are two of the main challenges for coal-fired power plants in China. This paper proposed a calcium looping (CaL) combustion system with cryogenic O2 storage for simultaneous flue gas decarbonization and peak shaving for a 1000 MWe coal-fired power plant. The philosophy of this concept is that: 1) the boiler always operates at maximum continuous rating (MCR) to ensure the highest boiler efficiency; 2) during off-peak times, the excess energy output from coal combustion is used to provide heat for the calciner and produce pure oxygen for energy storage; 3) at peak times, the O2 produced is used to capture CO2 in the flue gas via the CaL process and reduce the CO2 abatement penalty; and 4) any excess O2 is treated as a by-product for commercial utilization. The whole system was simulated in Aspen Plus ® which shows that the net electric efficiency of the proposed system without cryogenic O2 storage system is 35.52%LHV (LHV, low heating value), while that of the conventional CaL system is 34.54%LHV. The proposed system can reduce the methane consumption rate by 38.5 t/h when methane is used as fuel in the calciner. Including the cryogenic O2 storage system, the peaking capability of the proposed system can range from 534.6

The emission characteristics of Cl were investigated on the basis of the field experiments at three 410 t/h circulating fluidized bed boilers co-firing petroleum coke and coal. All of the boilers were equipped with advanced air pollutant control devices (APCDs) to meet the ultralow emission requirement, such as selective non-catalytic reduction, electrostatic precipitator (ESP) or fabric filters (FFs), and wet flue gas desulfurization (WFGD). Gaseous Cl was sampled simultaneously at both the inlet and outlet of the ESP or FFs and at the outlet of the WFGDs based on U.S. Environmental Protection Agency Method 26A. Feed fuel, limestone, bottom ash, ESP or FF ash, limestone slurry, flush water, wastewater, and gypsum were also sampled to determine Cl in each stream. Results showed that more than 86.1% of total chlorine was emitted into the flue gas in the gaseous form (e.g., HCl and Cl2). HCl was the dominant species in the flue gas at the outlet of boilers, accounting for 85.1–88.0%. The removal efficiencies of total chloride are 15.6% by ESP and 19.0–19.7% by FFs, respectively. The removal efficiencies of total chloride by WFGDs are in the range of 91.2–96.1%. The majority of total chlorine went into wastewater and gypsum, accounting for 76.16–80.19 and 11.35–12.76%, respectively. About 1.4–4.3% of total Cl was finally emitted into the atmosphere.