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The paper investigated the effect of metal nanopowders additive on the combustion properties of HMX/CL‐20/AP/polyvinyltetrazole binder/Al propellants. Using thermal analysis, the authors described the effect of aluminum, boron, zinc, nickel, copper, and molybdenum and identified the combustion in a pressure range from 4 to 10 MPa with a pressure step of 1 MPa. No significant correlation between the oxidation properties of the n‐Me powders and the combustion properties of propellants was discovered. An addition of nanopowders caused an increase in the propellant burning rate by approximately 30 % for n‐Al, n‐B, n‐Ni, and n‐Mo independent from the pressure values. An addition of n‐Cu resulted in a burning rate increase by a factor of 4.9 due to coppers’ probable catalytic activity during interaction with nitroesters and cyclic nitramines in a solid phase. n‐Zn additive increased the propellant burning rate by factors 2.3 and 3.6 at 4 and 10 MPa, respectively, due to catalytic activity of zinc in a gaseous phase.

Aluminum powders were comprehensively described as the prospective ingredients of the modern propellants. The paper also studied the influence of micro-and nanopowders of metals (μ-Me and n-Me) and metal oxides (μ-MeO and n-MeO) on the burning process of modern aluminized propellant with HMX, CL-20, AP, and active binder. The following metal additives were used: Al, B, Zn, Ni, Co, and Mo. The effect of the following oxides CoO, V 2 O 5 , MnO 2, and Fe 2 O 3 was studied together with LiF. The combustion tests of modified propellant compositions were carried out in the Vielle bomb in a pressure range 2-10 MPa. n-Me addition resulted in an increase in the burning rate by 10 % for n-B, by 30-40 % for n-Ni and n-Mo in the studied pressure range. The introduction of n-Cu caused a burning rate to increase fivefold. n-Zn additive resulted in increasing of the propellant burning rate by 130 % and 260 % at 4 and 10 MPa, respectively. It was probably caused by the catalytic activity of those metals in the gaseous phase. The effect of complex additive was observed to be insignificant for additives with μ-Co 3 O 4 , μ-V 2 O 5 , μ-Fe 2 O 3 and n-Fe 2 O 3 . The burning rate of propellant with n-CuO additive value was higher by a factor of 4 in comparison with the basic formulation in the studied pressure range.

The oxidation of lignite and bituminous coal samples modified by 5 wt% (in terms of dry salt) addition of copper salts Cu(NO3)2, CuSO4, and Cu(CH3COO)2 was studied. The samples’ reactivity was studied by thermogravimetry within a temperature range of 45–600 °C at a heating rate of 2.5 °C/min in an oxidizing environment. The introduction of activating additives has resulted in a significant decrease in the temperature of intense oxidation onset (ΔTi = 20/94 °C), in a reduction in the sample residence time in the volatile matter release region (Δte = 2/22 min) and the total duration of the coal combustible mass oxidation (Δtf = 8/14 min). The Friedman method was used to calculate the activation energy values for the oxidation process of the modified samples. The maximum change in activation energy values was observed for the bituminous coal sample. The possible mechanism behind the action of the copper-salt additives, which activate the oxidation of lignite and bituminous coal, is discussed. According to the data of mass spectrometric analysis, the concentration of NOx in the reaction products decreases as the temperature of the activated oxidation process is shifted towards the low-temperature region.

Non-isothermal oxidation of brown coal with 5 wt% of Cu(NO 3) 2 , 5 wt% of Ce(NO 3) 3 and {2.5 wt% Cu(NO 3) 2 ? 2.5 wt% Ce(NO 3) 3 } additives was studied. The introduction of additives was carried out by an incipient wet impregnation method to ensure uniform distribution of cerium and copper nitrates within the structure of coal powdery samples (according to SEM and EDX mapping). The samples reactivity was studied in an isothermal oxidation regime at 200°C (1 h) and by DSC/TGA at 2.5°C/min heating rate. The additives implementation was found to reduce significantly the oxidation onset temperature (DT i = 20-55°C), the samples oxidation delay time (Dt i = 2-22 min) and overall duration of the oxidation process (Dt c = 8-16 min). The additives efficiency could be graded in accordance with the activation on the coal oxidation in the following row: Cu(NO 3) 2 [ {Cu(NO 3) 2 ? Ce(NO 3) 3 } [ Ce(NO 3) 3. According to the mass spectroscopy, the obtained row of activation correlates well with the initial temperature of the studied nitrate's decomposition (from 190 to 223°C). A presence of nitrates was found to change significantly the trend of heat release taking place during the oxidation of coal samples (according to DSC/TGA data). The influence of coal morphology and volatiles content in initial sample on the parameters of the oxidation process was studied as well. Activation energy (E a) of the coal oxidation was calculated using Coats-Redfern method. Maximum decrease in E a from 69 to 58 kJ/mol was observed for the samples with Cu(NO 3) 2 .

Abstract. Experimental studies of bituminous coal and lignite oxidation were conducted with the addition of different nature catalytic additives: NaNO 3 and CuSO 4 . The results showed that added mineral salts led to a noticeable decrease in the coals initial oxidation temperature and reaction acceleration at an early stage of the process.

Abstract.The results of theoretical researches on efficiency of air heater use have been presented. The results of the research show the possibility of increase of energy efficiency of electrical power unit on electrical energy consumption by 2% at the initial temperature of steam 1073 K. The possibility of decrease of unit consumption of reference fuel by 4% has been stated.

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