Application of FTA based on SDG-HAZOP for production of polypropylene

The SDG-HAZOP(Signed Directed Graph,Hazard and Operability Analysis) is a qualitative safety assessment method,which is comprehensive,systematic and complete.However the result is tedious and large.Fault tree analysis(FTA) is a logical and diagrammatic method,which is proved to be a useful quantitative analysis tool to evaluate the safety and reliability of complex systems.So a FTA based on SDG-HAZOP quantitative method was proposed in this paper.Firstly,the SDG-HAZOP and the FTA were established on the background of polypropylene production devices in the Sinopec Wuhan Branch.Secondly,the probability of top event was calculated by reliable data from the probability of basic events.Finally,the targeted measures were proposed to prevent fatal potential dangerous situations by probability calculation.

Synthesis, Crystal Structure and Spectroscopy Studies on Complex cis-Os^Ⅱ(bpy)_2Cl_2 and Its Oxidation Product [cis-Os^Ⅲ(bpy)_2Cl_2](PF_6)

The treatment of(NH_4)_2 OsCl_6 with 2 equiv of bpy in ethylene glycol produced complex 1, cis-Os~Ⅱ(bpy)_2Cl_2(bpy = 2,2?-bipyridine). Its one-electron oxidation product 2, [cis-Os~Ⅲ-(bpy)_2Cl_2](PF_6), was obtained by the oxidation of 1 with(Cp)_2 FePF_6. Complex 1 crystallizes in the orthorhombic space group Pbca, and adopts distorted [MCl_2 N_4] octahedral coordination, in which four coordination sites are occupied by four nitrogen atoms from two bpy ligands and the other two sites are occupied by two chlorine atoms in a cis-position. Complex 2 crystallizes in monoclinic space group C2/c, and contains one [Os(bpy)_2Cl_2]^+ cation, one PF_6^- anion and two uncoordinated water solvent molecules.

Enhancing mineral liberation of a Canadian rare earth are with microwave pretreatment

Liberation. as an attribute of mineralogy characteristic. whose impacts on finely disseminated Canadian rare earth ore was studied with microwave pretreatment. Samples of a light rare earth ore along with mostly ankerite and biotite as dominant gangue minerals as well as bastnaesite, strontianite and goethite as dominated minerals were exposed to further comminution by ball mill and microwave pretreatment fragmentation. Mineralogical characteristics were analyzed by using a mineral liberation analyzer(MLA).The results indicated that tight association mutually penetrates among dominated minerals in the range size of -300 + 212 μm and 212 + 150 μm and gangue minerals in the form of adjacent type. fine vein type. shell type and packing type. Temperature in the ore samples pre-treated by microwave can rapidly rise to 250 ℃ with microwave power of 0-1.5 kW and microwave time of 0-2 min. Applying the microwave pretreatment merely reduces the hardness of the ore causing the fracture of rare earth ore, but this does not transform or change the original mineralogy characteristics of the ore samples. On the basis of above study. the liberation value of bastnaesite, strontianite and goethite with microwave pretreatment is greater than with conventional comminution when the liberation class is above 75%. The distribution of particle size of rare earth ore samples is better with microwave pretreatment than with conventional comminution for particle size of 7.4 × 10^(-5) m. With microwave pretreatment, the theoretical grade-recovery of bastnaesite. strontianite and goethite in the rare earth ore attains better results than with conventional comminution at a given grade.

Converting Thiophene in Simulated Coking Crude Benzene to N,N-Dimethyl-2-thiophenecarboxamide by Dimethylcarbamyl Chloride Under Mild Conditions

Since the content of thiophene in coking crude benzene is high, it is necessary to remove it from coking crude benzene for efficient utilization. In this study, an important intermediate, N,N-dimethyl-2-thiophenecarboxamide, was synthesized from thiophene and dimethylcarbamyl chloride. The influences of the dosages of dimethylcarbamyl chloride and ZnCl2 catalyst, reaction temperature and time on the removal rate were further explored based on the reaction kinetics.The structure of the target product was characterized by means of MS,NMR and 13C NMR.The removal rate of thiophene was 98.14% after the reaction for 2 h and thiophene was almost removed after the reaction for 3 h under the optimal reaction conditions [a molar ratio of n(thiophene):n(dimethylcarbamyl chioride):w(ZnCl2)=1:12:10,300 r/min, 318 K and 101.325 kPa].The acylation of thiophene with dimethylcarbamyl chloride was approximately in accord with the first order kinetic equation at 303-323K.The activation energy was 53.9850 kJ/mol and the pre-exponential factor was 1.4521×10^9 h^-1.

Metalloporphyrin receptors for histidine-containing peptides

Two new ditopic metalloporphyrin receptors constructed by combining metalloporphyrin with crown ethers have been prepared and characterized.1H NMR and MS spectra confirmed the complexation of receptor with peptide driven by coordination interaction and hydrogen bonding.UV/vis experiments revealed that the receptors exhibited high binding affinity to histidine-containing peptides.These receptors could differentiate short peptides of C-terminal histidine and N-terminal histidine and formed the most stable complexes with tripeptide.