Natural gas hydrates have vast reserves and are considered a new clean energy source for replacing traditional fossil fuels such as coal and oil in the future.The formation, inhibition and decomposition of natural gas hydrate are affected by many factors.When studying the inhibition and acceleration effect of chemical agents on hydrate decomposition,multiple factors should be considered, such as fresh water or sea water, different gas?liquid ratios in the reactor, and pressure. In this paper, hydrate?related simulation experiments were carried out through a self?designed visualization simulation device for hydrate formation,inhibition and decomposition in wellbore. Under a gas?liquid ratio of (150 : 350),the combined effects of a laboratory?prepared KHI3 inhibitor and different concentrations of NaCl were analyzed to determine the optimal concentration combination. The experiment found that under the compound scheme of 3%NaCl+1%KHI3, hydrate is not easy to generate, but when the concentration of KHI3 is 2%, the nucleation rate of hydrate increases instead,which promotes the generation of hydrate.In practical applications,the concentration of the inhibitor should be strictly controlled to avoid pipeline blockage caused by massive hydrate formation.

A nitrogen?doped carbon catalyst was prepared by the calcination of the CN _y precursor synthesized by the polymerization of paraformaldehyde,1,3,5?trimethylbenzene and p?phenylenediamine.This paper also investigated the effect of catalyst calcination temperature on the performance of acetylene hydrochlorination.The results indicate that CN _y ?700?1 catalyst has the best reaction activity.It has an acetylene conversion of up to 89.8% under the optimized conditions of acetylene?to?hydrogen chloride volume ratio of 1.0∶1.1,reaction temperature of 280 ℃ and GHSV(C₂H₂) of 90 h^-1.The catalyst characterization manifests that the activity of the catalyst is related to the specific surface area,pore volume,and pyrrole nitrogen content.The active site of the catalyst is the carbon atom bonding with the pyrrole nitrogen atom.Increasing the calcination temperature results in a larger specific surface area within a certain temperature range,and the pyridine nitrogen can also be converted to pyrrole nitrogen to a certain extent.The main cause of catalyst deactivation is carbon deposit.