Preheating feeding method of catalytic pyrolysis cracking (CPP) raw oil

Abstract

A preheating feeding method of catalytic pyrolysis cracking (CPP) raw oil includes that the raw oil is delivered from a raw material tank field to a raw oil buffer tank in a catalytic pyrolysis cracking device; the raw oil is extracted out of the raw oil buffer tank through a raw oil pump and is heated to be 240-250 DEG C by sequentially passing through a middle-section heat exchanger and a slurry oil heat exchanger, and 90-95 w% of the raw oil is directly delivered to a nozzle for feeding of raw materials at the bottom of a reaction settler of a lift tube, and the rest 5-10w% of the raw oil is delivered to a fractionating tower bottom for thinning slurry oil; the temperature of the slurry oil after catalytic pyrolysis cracking is 180-220 DEG C, the slurry oil is delivered to a quench cooler by a slurry oil pump for cooling high-temperature oil gas together with recycle oil, the temperature of the returned slurry oil heat exchanged by the quench cooler is 350-360 DEG C, and the slurry oil is returned to the fractionating tower bottom; and thinned slurry oil after heat-exchanging cooling is delivered to the nozzle for feeding of the slurry oil at the bottom of the reaction settler of the lift tube according to a quantity of 35-45 w% of the raw oil. By the aid of the preheating feeding method of the catalytic pyrolysis cracking raw oil, loss of the raw oil is guaranteed to be avoided.

Description

technical field [0001] The invention relates to the technical field of catalytic pyrolysis raw oil, in particular to a method for preheating feedstock of catalytic pyrolysis (CPP) raw oil. Background technique [0002] The so-called "CPP technology" is a technology for producing basic organic chemical raw materials mainly ethylene from heavy oil. The raw material oil preheating feeding method in the original design is that fresh raw material oil is sent from the raw material tank area to the raw material oil buffer tank in the device, and the temperature is about 80°C. The raw oil pump draws the raw oil from the raw oil buffer tank, and exchanges heat with the circulating oil in the middle section of the fractionation system and the circulating oil at the bottom of the tower, and the temperature rises to about 200°C. Then enter the oil-gas quencher to directly contact the high-temperature oil and gas from the reaction settler for heat exchange. Direct contact for heat exch...

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Problems solved by technology

[0003] This raw material oil preheating feeding method was applied in the trial run of the 500,000-ton / year heavy oil catalytic pyrolysis (CPP) to olefins demonstration plant of Shenyang Paraffin Chemical Co., Ltd., and there were two major problems. First, the so-called fresh raw material oil was Paraffin-based atmospheric residue, in the process of direct heat exchange between the quencher and the high-temperature oil and gas from the reaction settler, the components with lower boiling points (components with a distillation range between 320°C and 400°C) are easy to evaporate , enter the lower part of the fractionation tower together with the oil and gas, and partly enter the side line to extract light oil after fractionation, resulting in partial loss of fresh raw oil and seriously affecting the yield of products such as ethylene and propylene; The amount of green coke is large, the total yield is low, 85-90% of the feed amount will cause the regenerator to overheat (over 760°C), and the device cannot operate normally

To this end, it is necessary to make major improvements to the preheating feed method of feedstock oil in catalytic pyrolysis (CPP), develop a new feedstock preheating method, and solve the partial loss of feedstock oil in the original design, resulting in ethylene and propylene production. The rate is low; the amount of coke is large, and the regenerator is overheated, which causes the problem that the device cannot operate

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