When predicting the variation of pore structure during CO2 gasification of coal chars using the random pore model (RPM), it is impossible to calculate exactly the ψ parameter from the pore characteristics, which were obtained by means of N2 adsorption, such as BET surface area (denoted as N2 pore characteristics), of the char prior to gasification. The values of ψ, which were calculated from the pore characteristics of chars at various carbon conversions, should be fundamentally constant, unaffected by the conversion of the char. However, this investigation exhibited a drastic decrease of ψ at the initial stage of the gasification reaction. This phenomenon is the result of a significant increase of N2 pore characteristics, of which the starting chars are extremely small. This increase might be explained by the widening of submicropores which are undetectable through the N2 adsorption method or by the reopening of closed pores inaccessible even to helium molecules, followed by the formation of new micropores exceeding the detection limit of N2. Consequently, this study introduced the volume of submicropores and closed pores into the ψ equation as correction terms. The value of ψ at the reaction starting point was close to that at the intermediate stage of reaction, indicating that the accuracy for ψ estimation was elevated and that the submicropores and closed pores should be taken into account when using RPM.

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An 86-year-old female on dialysis experienced a decrease in blood pressure and worsening of her respiratory condition during dialysis, for which she visited our emergency unit. She was admitted to our Department of Cardiology with a diagnosis of acute myocardial infarction complicated with heart failure because of anterior wall of left ventricular dysfunction, positive troponin T levels and negative T wave on a precordial lead electrocardiogram. On the same day, she underwent coronary angiography and stenting at left anterior descending artery #7 with 99% stenosis. She also showed an elevated D-dimer level on admission, and contrast-enhanced computed tomography (CT) was performed the day after admission, considering the likelihood of respiratory failure due to pulmonary thromboembolism. However, the findings were negative. On the 4th day of hospitalization, she showed marked hypoxemia. Her D-dimer level was further elevated, and when she underwent enhanced CT again, there was no evidence of deep vein thrombosis, but thrombus in the pulmonary artery and apex of right ventricle was noted. She was therefore diagnosed with acute pulmonary embolism due to thrombosis from the right ventricle rather than from a deep vein. She rapidly received anticoagulant therapy and non-invasive positive pressure ventilation therapy for respiratory failure, but she entered cardiopulmonary arrest and quickly died. She was suspected to have been complicated with a right ventricular infarction and an acute anterior wall myocardial infarction, resulting in a large thrombus along the apex of the right ventricle. This case of both myocardial infarction and pulmonary embolism is very rare, and we report it here with consideration.