Data set of the effects of endogenous potassium and calcium metal ions on the characteristics of pyrolysis gas, solid and liquid products of corn stover

This dataset originates from the experimental study titled "Effects of Endogenous Potassium and Calcium Metal Ions in Corn Stalk on the Characteristics of Its Pyrolysis Gaseous, Solid, and Liquid Products," aiming to obtain correlated data between metal ion concentration, pyrolysis temperature, and the yield and characteristics of pyrolysis products (biochar, bio-oil, and syngas) through systematic experiments, with all data generated via experimental determination and standardized processing. The data generation process is as follows: first, experimental materials were prepared—corn stalks used as raw material were collected from farms in Guannan County, Lianyungang City, Jiangsu Province, crushed into powder with a particle size of 80–120 meshes using a crusher, dried to absolute dryness in an oven at 105°C, and then sealed for later use; the corn stalk powder (CS-Raw) was subjected to acid washing for ash removal by immersing it in 1 mol/L hydrochloric acid at a solid-to-liquid ratio of 1:10, stirring at room temperature for 12 hours, and then undergoing filtration, rinsing, and drying to obtain the ash-removed sample (CS-AW); subsequently, using KCl and CaCl₂ as metal sources, CS-AW was immersed in deionized water containing the corresponding metal salts at a solid-to-liquid ratio of 1:10, with metal ion concentrations (mass ratio relative to the raw material) set at 2%, 5%, and 7%, and after drying, metal-loaded samples (CS-K-2%/5%/7%, CS-Ca-2%/5%/7%) were obtained. Pyrolysis experiments were conducted using a self-made fixed-bed device (comprising a gas supply system with high-purity nitrogen cylinders, high-purity oxygen cylinders, and gas flow controllers; a reaction system with a temperature controller and a heating reactor; a liquid collection system with a low-temperature bath and a condenser; and a gas collection system with desiccants and gas collection bags); for each experiment, 3 g of sample was weighed and placed in a quartz tube, purged with N₂ for 10 minutes, then heated to 400°C, 500°C, and 600°C at a heating rate of 20°C/min, held at the target temperature for 20 minutes, and after cooling, the solid residual char was weighed (M1); the mass of the liquid product (M2) was obtained from the mass difference of the condenser, and the gas yield was calculated as 100% minus the solid yield minus the liquid yield. During data processing, the net organic char yield of biochar was calculated using the formula: "(mass of residual char − mass of metal salt) / (mass of raw material − mass of metal salt) × 100%"; the oxygen (O) content on a dry basis was derived by "100% − C − H − N − S − ash content"; the components of bio-oil were qualitatively analyzed via the peak area normalization method using a gas chromatography-mass spectrometry (GC/MS) instrument combined with the NIST spectral library; and the gas components were determined using a gas chromatography (GC) instrument equipped with a thermal conductivity detector (TCD) and a flame ionization detector (FID). Experimental characterization relied on various instruments: elemental analysis was performed using an Elementary Vario EL III Automatic Elemental Analyzer (Elementar, Germany); higher heating value was measured using a ZDHW-300A Microcomputer-Automatic Calorimeter (Keda Instrument Co., Ltd., Hebi City); proximate analysis was conducted in accordance with the GB/T 28731—2012 standard; the content of alkali and alkaline earth metals (AAEMs) was determined using an iCAP 7000 Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES, Thermo Fisher Scientific, USA); thermogravimetric analysis was carried out using a TG209 F1 Libra Thermogravimetric Analyzer (Netzsch, Germany) with an N₂ flow rate of 40 mL/min and a heating rate of 20°C/min up to 800°C; gas component analysis was performed using a GC9890B Gas Chromatograph (Renhua Chromatography Technology Co., Ltd., Nanjing) equipped with a Porapak Q column and a 13X molecular sieve; and liquid component analysis was conducted using an ISQ7000 Gas Chromatography-Mass Spectrometry (GC/MS) Instrument (Thermo Fisher Scientific, USA) with an HP-5MS capillary column and high-purity helium as the carrier gas. In terms of spatiotemporal information, there is no continuous time-series data in the time dimension, only instantaneous experimental data at three pyrolysis temperatures (400°C, 500°C, and 600°C), and all experimental operations were completed within the same time period to ensure consistent conditions; in the spatial dimension, the raw material was collected from a specific farm in Guannan County, Lianyungang City, Jiangsu Province (single-point sampling, no spatial gradient distribution), all experiments were conducted in the laboratories of the Bamboo Industry Institute and the College of Environment and Resources, Zhejiang A & F University, and the spatial resolution focuses on the laboratory experimental equipment and the raw material sampling point, with no large-scale spatial extension data. The table data includes 5 structured data tables (Table 1 to Table 5): Table 1, titled "Elemental and Proximate Analysis of Corn Stalk Before and After Acid Washing for Ash Removal and Metal Ion Loading," contains 8 records (covering CS-Raw, CS-AW, and 6 metal-loaded samples), with column labels including elemental analysis (C, H, O, N, S, unit: wt%, on a dry and ash-free basis (daf)), proximate analysis (volatiles, fixed carbon, ash, unit: wt%, on a dry basis (db)), and higher heating value (unit: MJ/kg); Table 2, titled "AAEM Contents in Corn Stalk Before and After Acid Washing for Ash Removal," includes 2 records (CS-Raw, CS-AW), with column labels including AAEM contents (K, Na, Ca, Mg, unit: μg/g) and removal rates (unit: %); Table 3, titled "Residual Char Rate of Corn Stalk Pyrolysis Under Different Concentrations of Potassium Ions and Calcium Ions," has 8 records (the same samples as in Table 1), with column labels being total residual char rate (unit: %) and net organic residual char rate (unit: %); Table 4, titled "Effects of Different Concentrations of Potassium Ions and Calcium Ions on the Basic Characteristics of Corn Stalk Pyrolysis Char," contains 8 records (the same samples as in Table 1), with column labels consistent with those of Table 1 (O is marked as O*, indicating a calculated value on a dry basis); Table 5, titled "Effects of Pyrolysis Temperature on the Elemental and Proximate Analysis of Corn Stalk Pyrolysis Biochar," includes 6 records (400-7% K, 500-7% K, 600-7% K, 400-7% Ca, 500-7% Ca, 600-7% Ca), with column labels consistent with those of Table 1. In terms of data integrity, there is no obvious data missing, and all samples designed in the experiment (8 basic samples and 6 temperature-metal combination samples) have undergone testing for key indicators such as elemental analysis, proximate analysis, yield determination, and component analysis; the sources of errors mainly include mass errors caused by balance precision during sample weighing (e.g., weighing of M1 and M2), leakage errors that may be caused by the tightness of gas collection bags during gas collection, relative analysis errors from the GC/MS peak area normalization method, and weight loss rate errors caused by sample uniformity in thermogravimetric analysis; the experiment reduced errors by controlling conditions such as N₂ purging time (≥10 minutes), heating rate stability (20°C/min), metal salt weighing precision, and consistency of the solid-to-liquid ratio for acid washing, and although no specific error range is clearly given, the data meet the precision requirements of conventional laboratory experiments (e.g., mass weighing error ≤ 0.001 g, temperature control error ≤ ±5°C). The types of data files include structured table data (Excel format), experimental graph data (thermogravimetric curves, product yield and component distribution diagrams, with source files in Origin format), device schematic diagrams (PPT format), and original instrument data (e.g., .raw format of GC/MS, which can be opened using Excel); there are no files in niche formats, and all files are compatible with conventional scientific research software.