A New Model for the Genesis of Natural Gases——Multi-source Overlap, Multi-stage Continuity, TypeControlled by Main Source and Nomenclature by Main Stage (Ⅱ)——Multi-stage Continuity and Nomenclature by Main Stage

The generation of natural gases involves several stages and the various stages are of continuous transition. This is another feature of natural gas generation. The term "multi-stage" is relative mainly to oil-generating threshold value and liquid window. The evolution of organic matter is affected by different epigene agencies and natural gases differing in geochemical properties such as biogenic gas (bacterial gas), thermocatalytic gas and pyrolytic gas could be produced at different stages of the evolution of organic matter. The proposal of bio-thermocatalytic transitional-zone gas presents a pattern of mutual linking and continuous transition of natural gases originated at different stages.In the genetic classification of natural gases, the nomenclature of a certain gas is based mainly on the epigene agency which is responsible for its formation, for example, biogenic gas, pyrolytic gas. That is the "nomenclature by the main stage" described in this study. On account of the continuity of gas generati     

PRELIMINARY STUDY OF HYDROCARBONS GENERATED FROM FUSHUN COAL RESINITE (Ⅰ)——PRODUCTIVITY AND NATURE OF HYDROCARBONS

Thermal simulation experiments were conducted to understand the productivity of hydrocarbons andtheir nature. It is shown by the experimental results that coal resinite has a high productivity of hydro-carbons and may be a good source rock, resulting in light oils of low maturity in early stage. Naturalgases generated from coal resinite are rich in high molecular weight gas hydrocarbons (C_2~+), up to 19%(V/V). So, if natural gases were generated from coal formation which is rich in resinites, they cannotbe recognized as dry gases as normal. Characteristics of liquid hydrocarbons generated from coal resinitesare: (i) main composition of aromatics in extracts, of which the amount will increase with increasingmaturity; (ii) major compounds of diterpenoids in aliphatics.     

Initial estimation of hydrate formation temperature of sweet natural gases based on new empirical correlation

Production,processing and transportation of natural gases can be significantly affected by clathrate hydrates.Knowing the gas analysis is crucial to predict the right conditions for hydrate formation.Nevertheless,Katz gas gravity method can be used for initial estimation of hydrate formation temperature (HFT) under the circumstances of indeterminate gas composition.So far several correlations have been proposed for gas gravity method,in which the most accurate and reliable one has belonged to Bahadori and Vuthaluru.The main objective of this study is to present a simple and yet accurate correlation for fast prediction of sweet natural gases HFT based on the fit to Katz gravity chart.By reviewing the error analysis results,one can discover that the new proposed correlation has the best estimation capability among the widely accepted existing correlations within the investigated range.     

Selective Catalytic Reduction of NO with Methane

The removal of nitrogen oxides from exhaust gases has attracted great attention in recent years, and many approaches have been developed depending on the application. Methane. the main component of natural gas, has great potential as a NO reductant. In this paper, a number of catalysts previous reported for this catalytic reduction of NO have been reviewed, including a direct comparison of the relative activities and effective factors of the catalysts. Reaction mechanisnls have also been explored preliminarily.     

Nitrogen-doped graphene as an excellent candidate for selective gas sensing

The toxic gases,such as CO and NO,are highly dangerous to human health and even cause the death of person and animals in a tiny amount.Therefore,it is very necessary to develop the toxic gas sensors that can instantly monitor these gases.In this work,we have used the first-principles calculations to investigate adsorption of gases on defective graphene nanosheets to seek a suitable material for CO sensing.Result indicates that the vancancy graphene can not selectivly sense CO from air,because O2 in air would disturb the sensing signals of graphene for CO,while the nitrogen-doped graphene is an excellent candidate for selectivly sensing CO from air,because only CO can be chemisorbed on the pyridinic-like N-doped graphene accompanying with a large charge transfer,which can serve as a useful electronic signal for CO sensing.Even in the environment with NO,the N-doped graphene can also detect CO selectively.Therefore,the N-doped graphene is an excellent material for selectively sensing CO,which provides useful information for the design and fabrication of the CO sensors.     

前言(英文)

正We are now facing the emerging problems of how to use the oil, natural gas and coal-based existing energy in a more efficient way and how to develop new energy sources including solar and bio-energy under the resource- diminishing circumstances. In the meantime, environmental protection is a key to the sustainable development of the world.     

Characteristics of Carbon Isotopes of Alkane Components and Identification Marks of Biogenic Gases in China

The carbon isotope composition of alkane component in biogenic gases of China has the following characteristics:with the increase of carbon number of the alkane molecules in biogenic gases, (i) the distribution range of the δ13C values and their main frequency sections become narrower, and both the heaviest and the lightest δ13C boundary values shift to their heavier end; (ii) the δ13C values of ethane and propane in biogenic gases present a positive linear relationship and (iii) the values of δ13C1, δ13C2 and δ13C3 tend to become heavier with the increase of heavy alkane component (C2+3) in biogenic gases. The authors studied the relationship between the δ13C values and the amount of heavy alkane components in biogenic gases (δ13C1 -C2+3(%). δ13C2 -C2+3(%) ,δ13C3-C2+3(%) for the first time and set up the interrelated regression equations between δ13C and C2+3 content (C2+3%), and advance that δ13C1< -55‰ and C2+3<0. 5% are two fine marks for identification of biogenic gases of China. δ13C     

Modeling phase equilibria of semiclathrate hydrates of CH_4,CO_2 and N_2 in aqueous solution of tetra-n-butyl ammonium bromide

Semiclathrate hydrates of tetra-n-butyl ammonium bromide(TBAB) offer potential solution for gas storage,transportation,separation of flue gases and CO2 sequestration.Models for phase equilibria for these systems have not yet been developed in open literatures and thus require urgent attention.In this work,the first attempt has been made to model phase equilibria of semiclathrate hydrates of CH4,CO2 and N2 in aqueous solution of TBAB.A thermodynamic model for gas hydrate system as proposed by Chen and Guo has been extended for semiclathrate hydrates of gases in aqueous solution of TBAB.A correlation for the activity of water relating to the system temperature,concentration of TBAB in the system and the nature of guest gas molecule has been proposed.The model results have been validated against available experimental data on phase equilibria of semiclathrate hydrate systems of aqueous TBAB with different gases as guest molecule.The extended Chen and Guo's model is found to be suitable to explain the promotion effect of TBAB for the studied gaseous system such as,methane,carbon dioxide and nitrogen as a guest molecule.Additionally,a correlation for the increase in equilibrium formation temperature(hydrate promotion temperature,ΔTp) of semiclathrate hydrate system with respect to pure gas hydrate system has been developed and applied to semiclathrate hydrate of TBAB with several gases as guest molecules.The developed correlation is found to predict the promotion effect satisfactorily for the system studied.     

Comparative study of fluidized-bed and fixed-bed reactor for syngas methanation over Ni-W/TiO₂-SiO₂catalyst

In this work,syngas methanation over Ni-W/TiO2-SiO2catalyst was studied in a fluidized-bed reactor(FBR)and its performance was compared with a fixed-bed reactor(FIXBR).The effects of main operating variables including feedstock gases space velocity,coke content,bed temperature and sulfur-tolerant stability of 100 h life were investigated.The structure of the catalysts was characterized by XRD,N2adsorptiondesorption and TEM.It is found that under same space velocity from 5000 h 1to 25000 h 1FBR gave a higher CH4yield,lower coke content,and lower bed temperature than those obtained in FIXBR.Ni-W/TiO2-SiO2catalyst possessed excellent sulfur-tolerant stability on the feedstock gases less than 500 ppm H2S in FBR.The carbon deposits formed on the spent catalyst were in the form of carbon fibers in FBR,while in the form of dense accumulation distribution appearance in FIXBR.     

Simple Fluorimetric Determination of Benzo[a]pyrene in Cigarette Smoke without Preseparation Procedure

Polycyclic aromatic hydrocarbons(PAHs)are important environmental pollutions originating from a wide variety of natural and anthropogenic sources.Benzo[a]pyrene is frequently sought as an indicator of the presence of other PAHs.Fluorescence spectrometry serves as a good technique to analyze PAHs with high sensitivity.However,this technique is unfavorable for the analysis of benzo[a]pyrene in multi-component PAHs because of spectral overlap.This complication can be simplified by using spec…