The kinetic analysis for non-isothermal solid state reduction of nickel laterite ore by carbon monoxide was investigated at four different heating rates (5, 10, 15 and 20 K min 21 ). The mechanism function f(a) and kinetic parameters of the reduction process of nickel laterite ore were determined by the thermogravimetric curves using Coats-Redfern method, and the reduction mechanism of nickel laterite ore was analysed. The results indicated that the degree of conversion a could be considered as a function of the temperature, and heating rates had less effect. There was clear relationship between calculated values and measured values of the degree of conversion by mathematic model verification. The kinetic analysis for non-isothermal reduction of nickel laterite ore was divided into three stages for 200-600uC, 600-800uC and 800-950uC; activation energies were 32?16 kJ mol 21 for 200-380uC, 33?13 kJ mol 21 for 380-600uC respectively, for the initial stage, which was characterised by a very slowrate; activation energy was 60?78 kJ mol 21 for the middle stage, which was characterised by a very fast rate; the reduction of nickel laterite ore remained a sluggish process at the decaying stage, and the reaction was governed by the diffusion of oxygen. The mechanism function belonged to G-B equation with differential forms f(a)53/2[(12a) 21/3 21] at the initial stage, and that belonged to Avrami-Erofeer equation (n54) with differential form f(a)51/ 4(12a)[2ln(12a)] 23 at the middle stage.

With the advantages of ultra-low emissions of oxides of nitrogen (NOX) and high thermal efficiency, the homogeneous charge compression ignition (HCCI) mode applied to marine diesel engine is expected to be one of the technical solutions to meet the International Maritime Organization (IMO) MARPOL73/78 Convention-Annex VI Amendment Tier III requirement. According to the NOX chemical reaction mechanism, taking a marine diesel engine as the application object, the numerical study on the NOX formation characteristics of n-heptane for HCCI combustion process is performed. The results indicate that NO is usually the main component in the generation and emissions of NOX with the n-heptane HCCI mode. The combustor temperature plays more important role in the proportion of NO generation and emission. Compared with the experimental data of conventional marine diesel engine, the emission reduction rate of NOX can achieve an average of more than 95% in using HCCI technology.