Exhaustive refining of crude oil under low hydrogen pressure

Abstract

Traditional methods of refining crude usually provide for its dehydration, desalting, and preliminary fractionation. The last process is accompanied by transformation of high-boiling cuts in low-reactivity mixtures of compounds, whose subsequent refining into light products requires the use of repetitive, complex, and expensive manufacturing processes.Vacuum resid undergoes visbreaking under 500°C and an insignificant (11%) amount of naphtha cut is formed [1]. Thermal cracking of atmospheric resid at hydrogen-containing gas pressure of 3 MPa [2] gives almost the same yield of light cuts. For this reason, both domestic and foreign processes for refining heavy residues into motor fuels provide for use of high-pressure (15-20 MPa) hydrogen, which is economically burdensome. Vacuum resid can be refined into light petroleum products at a pressure of 10 MPa, but in this case, an important amount of vacuum distillates is formed [3], and new catalysts are required for refining them into naphtha and diesel cuts [4].To simplify and make refining of crude less expensive, to increase the yield and quality of valuable products, and to solve the problem of using heavy residues, a new concept was developed in [5][6][7]. The crude oil is first refined by hydrogenation under low (4-7 MPa) pressure without the classic preparation, including without preliminary fractionation. The distillates formed are hydrorefined and hydrotreated in one process chain. A homogeneous nanocatalytic system based on water-soluble compounds of such metals as molybdenum, nickel, iron, etc., 0.05-0.5 wt. % in crude, is used for initial hydrogenation of the crude. Added to the feedstock in the form of a true solution in the water usually contained (3-10%) in crude, they recycle in the system with the high-boiling cuts that ensure that hydrogenation reactions take place. Explosive decomposition of the feedstock emulsion with the added catalyst and uniform distribution of nanoparticles of the catalyst in the volume of the feedstock primarily on the surfaces of large globules take place on heating.The hydrogen donors in native crude in the form of hydroderivatives of bi-and tricyclic aromatic hydrocarbons transfer hydrogen to unsaturated compounds and stabilize products of a radical nature formed in 0009-3092/06/4204-0255