Small-scale motor fuel plant

Abstract

665.63.(KI2.5 In recent years in the opening up of low-yield oil fields and small gas condensate deposits the processing of liquid hydrocarbons extracted by a plant has undergone development in order to satisfy the region's own requirements. An analysis of the proposals of the companies supplying motor fuel plants (MFPs), consumer demand, and the purchasing power of the owners of the deposits indicates that there is a market in Russia for plants with a feedstock capacity of about 3000 tons/year. In turn, the minimum capacity of motor fuel plants proposed by other firms is restricted to 5000 tons/year. It has become possible to produce profitable plants with a capacity of 1000-3000 tons/year by using animproved rectification process in the MFP. These plants are manufactured as a block module and are located at the site of oil or gas condensate extraction. Either gas obtained from oil separation or gas liberated from superheated oil is fed to the plant furnace.Liquid obtained during the separation of oil-well production at an absolute pressure of 0.12-0.15 MPa is the feedstock for the MFP. The most suitable feedstock for the plant is a hydrocarbon feedstock with a high content of diesel fractions and also a feedstock containing about 2% water and about 200 ml/liter of salts. The capacity can vary over a 30% range relative to the design capacity.The process scheme for an MFP is shown in Fig. 1. Feedstock stream 1 is pumped into the tubular section of heatexchanger H-l, which serves at the same time as a condenser for the gasoline vapor coming from eolunm C-1. The oil heated in the heat-exchanger passes into tilter F-1 for high-purity separation of water and mechanical impurities and then enters the circular space of the upper tube still of the heat-exchanger-eolunm C-1. The oil is heated with vapor in the intertubular space and debutanized. The debutanization gas 2 rises to the top of the inner tube still and passes out of the column, being flared off or fed into furnace F-1. The quantity of off-gases from debutanization is regulated by valve VR-1.The liquid from the upper tube still passes into the second tubular section of stabilizer S-I, where the gasoline fraction is a'lpped from the feedstock by means of the heat of condensation of the diesel fraction. The directly distilled gasoline obtained in the tubular space of the upper section of the column is withdrawn in gaseous form. In turn, the heavy (stripped) feedstock fraction passes into the furnace coil. The diesel fraction (the fraction vaporizing at 280-300"C) passes from the coil into the lower section of the tubular space of column C-I, where the heavier components are separated from the diesel fractions as a result of the partial condensation of the rising vapors. The diesel fuel vapor condenses in the rising stream in the upper zone of the tubular cluster. Partitions are distributed in the tubular space to ensure flow of the liquid obtained.The resulting gasoline fraction 3 condenses and is cooled in heat-exchanger H-l, transferring its heat to feedst...