Preparing Of Ethylene And Propylene From Syngas With High Selectivity

Light olefins play a significant role in modern petroleum and chemical industry as the most fundamental organic chemical raw materials. With the reduction of oil reserves and the rise of oil price, it is desirable to find oil substitutes. It has become important to develop new technique to prepare chemical raw materials from non-oil resources. To study and develop the synthesis route to prepare light olefins from non-oil resources, which is of significance for promoting the industry development of areas that are scarce of oil and putting state resources to balance and rational use. On the basis of the previous achievement of Fe-Mn-K/AC catalyst, this paper systematically study the influence of preparing process, chemical composition and proportion, reaction process on the Fe-Mn-K-Cu/AC catalyst, and also this paper explore and study the olefin metathesis catalyst, and also the multi-component F-T synthesis and metathesis double-function catalyst preliminary.The research results of catalyst preparation indicates that coconut shell active carbon is optimal carrier, water as solvent, AEO-3as dispersant and EDTA as complexing agent. Immersion method under vaccum as preparation method are suitable choice then dry at50℃, calcine at700℃for6h to prepare Fe-Mn-K-Cu/AC catalyst. The best final catalyst makeup are Fe:Mn: K:Cu:AC=36:17:6:5:36(mass ratio). XRD results indicate that before reaction catalyst main structure are a-Fe,(Fe,Mn)O, and also Fe2O3and CuO; after reaction a-Fe and (Fe,Mn)O structure weaken, Cu and new FexCy structure formed.Research about catalyst application finds that the optimum catalyst testing technological condition is as follows:online reduced at260℃for2h, then350℃for4h under H2atmosphere with space velocity of1800h-1, then continue to react at360℃and1.6MPa under synthesis gas(N2:CO:H2=1:1:2, mol ratio) atmosphere with space velocity of600h-1. Under this conditions, CO conversion was about94-96%, hydrocarbons selectivity in gaseous products was65%, olefins content in hydrocarbons was62%-65%, and olefins yield could reach about39.5%. Al2O3as carrier, Mo as active component, Mg as promoter to prepare olefin metathesis catalyst. Catalyst makeup are Mo:Mg:Al2O3=10:2:88(mass ratio). Catalyst increase to100℃under N2with space velocity of800h-1, then switch to mixed gas of C2H4and N2(C2H4:N2=1:1, mol ratio) with space velocity of510h-1, then increase to360℃. Then pumped in mixed C4hydrocarbons with20%(mass percentage content)2-C4H8and n-C4H8, react at360℃and1.0MPa with C4hydrocarbons liquid hourly space velocity of 2.5h-1.C2H4conversion can reach92%, C3H6selectivity can reach5%.The paper also explore and study the multi-component F-T synthesis and metathesis double-function catalyst preliminary.