Oxidation process of iron sulfides was observed by installation of oxidation experiment．Oxidation process of iron sulfide can be divided into three stages ：surface layer self －heating period，incubative period and accelerative oxidation period． Heat gathering was the key factors for iron sulfide self －ignite．Effects of oil，water content and sulfur on heat gathering were explored using oxidation experiment installation．The results show that oil has complicate effect on self － ignite of iron sulfide．Water content can prevent iron sulfide from oxidizing．Sulfur has a little effect on initial stages of self －ignite，while in the final stage it can be as external heat source．

The leakage and dispersion risk of certain chemical facility was always difficult to evaluate quantitatively because of the existing of many uncertain parameters in evaluation models. For this reason, taking weather data of Nanjing and some other cities as data sources, STATISTICA 6.0 was used to study the distribution of wind speed, humidity, air temperature and cloud cover rate, etc. And their respective distribution functions were proposed. The distributions of leakage orifice area and leakage orifice direction were also analyzed and reasonable distribution functions were gotten. As a widely used software package for leakage and dispersion, HGSYSTEM was chosen to unite Monte-Carlo method to form a quantity risk analysis method for chemical facilities. An accessory pipe (20 cm) of a propane tank (normal temperature, high pressure) was taken as a demo, and the influencing distances of two cloud blocks, with the concentration of 2.1%(lower explosion limit) and 0.015 3%(Russia MAC), were calculated for different cumulative probability, among which, when the cumulative probability is 95%, the two distances are respectively 69.7 m and 2 764 m.

On the base of basic theory of view factor, the view factor computation technology of pool fire with cross wind was studied. Related formulas for key parameters of view factor calculation were deduced according to the geometry topology, and further, the radiation surface of pool fire with cross wind was reasonably separated to establish the numerical computation formula of view factor. A procedure was developed using VB 6.0 for calculating view factor of pool fire with cross wind. From samples calculation, it was found that the procedure is reliable for pool fire without cross wind by comparing the result with what from theoretical model, and the new method can also effectively conquer the empirical model's shortcoming: incapable of calculating the view factor of pool fire with cross wind.

Gas explosion′s influence analyzing on plant layout was divided into three steps, which were flammable gas scope confirmation, explosion energy confirmation and distance confirmation for different units. Considering both the maneuverability and creditability of the system, appropriate methods were proposed for the three steps: suitable empirical gas dispersion models for flammable gas scope confirmation; TNO multi-energy model for explosion energy confirmation; shock wave′s different harm classes on people and facility were chosen as performance-based targets for distance confirmation between different units. With ALOHA as the gas dispersion computation tool, a plant layout design drawing of a methanol decomposing hydrogen factory in Nanjing was taken as an example to demonstrate the flow, from which the disadvantages of the design drawing are brought forward, and a new plant layout design drawing is put forward, and the feasibility of the flow is thereby validated.