FIELD: chemistry.
SUBSTANCE: method includes the following steps: a) reacting oxygen-containing material, which contains at least one oxygen atom and from 1 to 4 carbon atoms and a diluent, taken in amount of 0.1: 1 to 5:1 mole of diluent per mole of oxygen-containing compound respectively, with a bifunctional catalyst which contains a molecular sieve, which can convert at least one part of the oxygen-containing compounds to propylene and disproportionate olefins C2 and C4+ to propylene (olenfins C3), in a reaction zone, which contains at least one reactor with a fixed or moving catalyst bed, where duration of the operating cycle of the catalyst in the said reaction zone is 400 hours or less, temperature ranges from 350°C to 600°C, pressure from 10.1 kPa to 10.1 MPa and hourly rate from 0.1 to 100 h-1, which allows for efficient selective conversion of oxygen-containing compounds to propylene, with the aim of obtaining effluent which contains basic amount of olefin product C3-propylene and a water by-product, and less amount of olefin C2, olefins C4+, saturated hydrocarbons C1-C4+ and small amounts of unreacted oxygen-containing compounds, by-product oxygen-containing compounds, diene, acetylene and aromatic hydrocarbons; b) feeding the effluent to the separation zone, where the effluent is cooled and separated into a vapour fraction which is rich in olefin C3, a water fraction, which contains unreacted oxygen-containing compounds and by-product oxygen-containing compounds, and a liquid hydrocarbon fraction, which contains heavy olefins, heavy saturated hydrocarbons and a small amount of aromatic hydrocarbons; c) recirculation of at least part of the water fraction extracted from step b) to step a) in order to provide part of the diluent used there; d) separation of the vapour fraction and the fraction rich in olefin C3, a fraction of a product which is rich in propylene (olefin C3), and a fraction which is rich in olefins C4+, which contains diene and acetylene hydrocarbons; e) concentration of at least part of the fraction which is rich in olefins C4+, and hydrogen with a metal-containing hydrogenation catalyst in selective hydrogenation conditions, which are effective for converting diene and acetylene hydrocarbons contained in that fraction, to corresponding olefins, and that way, coke precursors are eliminated; and f) feeding at least part of the C4+ fraction, which is rich in olefins, formed from selective hydrofining, to stage a) in order to increase propylene output.
EFFECT: increased operating cycle average selectivity towards propylene when converting oxygen-containing compounds to propylene.
9 cl, 1 dwg
