CN1315490A - Process for preparing needle petroleum coke from ordinary-pressure residual oil - Google Patents

Abstract

A process for preparing needle petroleum coke from normal pressure residual oil includes such steps as slow heat-treatment of normal pressure residual oil and cyclic oil generated in coking procedure, coming into delay coking equipment, low-temp. long-duration liquid-phase reaction to generate needle petroleum coke staying in coke tower, and separating the coking oil-gas in fractionating tower. Its advantages include high quality, low investment for equipment and long service life of heater.

Description

A kind of method of producing acicular petroleum coke from long residuum

The invention belongs to a kind of under the situation that does not have hydrogen the thermal non-catalytic cracking method of hydrocarbon ils, more particularly, be a kind of method of producing acicular petroleum coke from long residuum.

Acicular petroleum coke (being called for short pin Jiao) has advantages such as thermal expansivity (hereinafter to be referred as CTE) is low, graphitization characteristic is good, broken back outward appearance is needle-like, have tangible filamentary structure and higher anisotropy at microscopically, be the framework material of making the superpower electrode, therefore be widely used on the Steel industry.

In the superpower steel-smelting electric furnace, must adopt superpower or ultra-high power graphite electrode, this electrode can stand the impact of severe condition jumpy at short notice.Burst for electrode being unlikely produce bigger thermal stresses when rapid heating or the chilling, require the CTE of electrode little, and the CTE of electrode depends primarily on pin Jiao's CTE, so CTE becomes the critical index of the burnt quality of expression pin.

The index of the burnt quality of pin is as follows:

True density, gram per centimeter ³＞2.12

CTE, * 10 ^-6/ ℃ 2.35～2.60 (1000 ℃ of carbon rod sample preparation methods)

Sulphur content, heavy % ≯ 0.7

Ash, heavy % ≯ 0.15

The burnt production technology of pin is a theoretical basis with the mesophasespherule formation mechanism, the general raw material that adopts is rich in aromatic hydrocarbons such as fluid catalytic cracking decant oil, thermal cracking residue, lube oil furfural refining extraction oil or preparing ethylene by steam cracking residual oil etc., though more than these raw materials can produce pin Jiao through different preprocessing method of raw materials, but because therefore resource-constrained is difficult to organize more massive industrial production.

Be used to produce pin Jiao's raw material, generally derive from secondary processing residual oil such as fluid catalytic cracking decant oil, lubricating oil is extracted oil, ethylene bottom oil and thermal cracking residue out, because these stock oils are the byproduct in the refining of petroleum, limited amount, therefore, the device of producing pin Jiao is difficult to the scale that reaches certain, cause difficulty to operation, shutting down is frequent, can not obtain ideal benefits, and the straight run residue wide material sources, as raw material, can form the throughput of economic scale.

Straight run residue is the problem that people study as the raw material of producing pin Jiao directly always, for example: USP4,178,229 disclose a kind of method of producing high-quality petroleum coke from straight run vacuum residuum, earlier vacuum residuum is converted into distillate and pitch, pitch is more further with the raw material of hydrogen supply agent cracking as production high-quality Jiao.This method adopts the hydrogen donor cracking process to handle straight run residue, has increased running cost and expense relatively.

USP4,130,475 disclose a kind of method of producing high-quality petroleum coke from long residuum.The main raw material of this method is a long residuum, and mix the small part ethylene bottom oil, this part ethylene bottom oil is handled without other and is directly entered delayed coking unit, it is light that coker produces, heavy distillate carries out heat cracking reaction through two thermally splitting process furnace respectively, the thermal cracking residue that reaction generates turns back to coking charging and long residuum again, the small part ethylene bottom oil mixes, because this method is not carried out chemical treatment to long residuum, just mix with other raw material, so this method has special restriction to long residue feed, raw material come that source range is corresponding to be dwindled.

The objective of the invention is to provide on the basis of existing technology a kind of method of producing acicular petroleum coke from long residuum.

Method provided by the invention is: long residuum and coking recycle oil are together after relaxing thermal transition, the lighting end that generates comes along with coking oil gas and separates, remaining last running enters coke drum after the process furnace heating, the coke that generates is stayed in the coke drum, coking oil gas obtains gas, gasoline, diesel oil, wax oil and turning oil through fractionation, and wherein turning oil and long residuum relax thermal transition together.

Detail operations process of the present invention is:

Long residuum after the preheating and coking recycle oil enter together and relax the thermal transition process furnace, this furnace outlet temperature is 370 ℃～510 ℃, water injection rate accounts for 0～20 heavy % of charging (being long residuum and coking recycle oil sum), and pressure is 0～1.0 MPa, 2～180 seconds residence time.

Logistics after thermal transition enters surge tank and is divided into lighting end and last running, wherein lighting end enters coking fractional distillation column with the coking oil gas that coking produces, be separated into gas, gasoline, diesel oil, wax oil and turning oil, remaining last running is introduced into the convection zone preheating of process furnace, enters the radiation section heating of process furnace then.Its operational condition is different with conventional coking, and conventional coking is a constant temperature method, and production pin Jiao's coking is the alternating temperature operation, and the scope of alternating temperature is 430 ℃～520 ℃.

The logistics that heated enters coke drum, and its operational condition is: the coke tower top pressure is 0.1～3.0 MPa, 380 ℃～450 ℃ of coke tower top temperatures.Acicular petroleum coke is stayed in the coke drum, coking oil gas is overflowed from the coke cat head, enter separation column with the lighting end that relaxes the thermal transition generation, be separated into gas, gasoline, diesel oil, wax oil and turning oil, wherein turning oil mixes with long residuum as the raw material that relaxes heat conversion device, and the weight ratio of turning oil and long residuum is 0.2～1.0: 1.

The used long residue feed of the present invention is the long residuum of any crude oil, and with arbitrary proportion blended long residuum.

Below in conjunction with accompanying drawing method provided by the present invention is given further instruction.

Accompanying drawing illustrates a kind ofly produces the flow process of the method for acicular petroleum coke from long residuum, and the shape and size of equipment and pipeline are not subjected to the restriction of accompanying drawing, but determine as the case may be.

The technological process of the method is: from the reduced crude of pipeline 1 and from the recycle oil of pipeline 16 together successively through pump 2, pipeline 3 enter relax thermal transition heating furnace 4 after, reacted logistics enters surge tank 6 through pipeline 5, the light fraction of separating from surge tank enters coking fractional distillation column 15 from the top through pipeline 14, heavy distillat then enters the convection section of coking heater 10 through pipeline 7, pump 8, pipeline 9, then directly enter the radiant section of coking heater 10, be the alternating temperature operation this moment, then enter coke drum 12 or 13 through pipeline 11, acicular petroleum coke is stayed in the coke drum, the oil gas that generates enters fractionating column 15 through pipeline 13 with the light fraction from pipeline 14, fractionation obtains gas, gasoline, diesel oil, wax oil and recycle oil, and wherein recycle oil mixes the charging of conduct mitigation thermal transition heating furnace 4 through pipeline 16 and the reduced crude from pipeline 1.

The invention has the advantages that:

1, reduced crude is through after relaxing thermal conversion reaction, and its chemical composition changes, and is conducive to the generation of mesophasespherule, and as the acicular petroleum coke that raw material is produced, CTE is less than 2.6 * 10^-6/ ℃, its quality reaches pin Jiao's requirement.

2, the fluid product of the light fraction of mitigation thermal transition generation and coking generation can be saved the investment of equipment so jointly in the coking fractional distillation column fractionation.

3, coking recycle oil and fresh feed oil are mixed into the mitigation heat conversion device, namely can change chemical composition with reduced crude, are conducive to the growth of mesophasespherule, can be conducive to again relax the long period operation of heat conversion device heating furnace.

The following examples will give further instruction to method provided by the invention, but not thereby limiting the invention.

Embodiment 1

It is raw material that present embodiment adopts long residuum A, and its character sees Table 1, and A long residuum sulphur content is 0.34 heavy % as can be seen from Table 1, and aromatic hydrocarbons and gum level sum are near 70 heavy %.

Testing apparatus is medium-sized delayed coking testing apparatus and medium-sized mitigation thermal transition testing apparatus, wherein relaxes heat conversion device and comprises a process furnace, and a surge tank and corresponding recovery system, processing power is 10 kilograms/hour; Delayed coking testing apparatus major equipment has process furnace, coke drum and separation column, and each coke drum capacity is 50 kilograms, and the operational condition and the material balance of device see Table 2, and product property sees Table 3.

As can be seen from Table 3, long residuum A is 0.39 heavy % through relaxing the burnt sulphur content of pin that goes out through coking production again after the thermal transition processing, and CTE is 2.57 * 10 ^-6/ ℃, meet pin Jiao's specification of quality.

Embodiment 2

It is raw material that present embodiment adopts long residuum B, and its character sees Table 1, and as can be seen from Table 1, B long residuum sulphur content is 0.21 heavy %, and aromatic hydrocarbons and gum level sum are 66.85 heavy %.Testing apparatus is identical with embodiment 1.Operational condition and material balance see Table 2, and product property sees Table 3.

As can be seen from Table 3, long residuum B is 0.33 heavy % through relaxing the burnt sulphur content of pin that goes out through coking production again after the thermal transition processing, and CTE is 2.49 * 10 ^-6/ ℃, meet pin Jiao's specification of quality.

Table 1

Stock oil	????A	????B
			Density (20 ℃), gram per centimeter 3Viscosity (100 ℃), millimeter 2/ second carbon residue, heavy % constituent content, the group composition of the hydrocarbon sulphur nitrogen of heavy %, heavy % stable hydrocarbon aromatic hydrocarbons gum asphalt	?0.9684 ?146.8 ?11.2 ?87.45 ?11.47 ?0.34 ?0.74 ?28.6 ?30.1 ?38.7 ?2.6	????0.9653 ????474.8 ????6.5 ????86.46 ????11.61 ????0.21 ????0.45 ????32.94 ????35.10 ????31.75 ????0.21

Table 2

The embodiment numbering	????1	????2
			Stock oil	????A	????B
Operational condition
			Relax thermal transition
The furnace outlet temperature, ℃	????435	????431
			Water injection rate, heavy %	????2.0	????2.2
The residence time, second	????75	????83
			Recycle ratio	????0.20	????0.41
Delayed coking
			The furnace outlet temperature, ℃	440～510	?440～510
The coke tower top pressure, MPa	????0.30	????0.30
			Material balance, heavy %
Gas	????14.5	????15.9
			Gasoline	????16.9	????13.9
Diesel oil	????23.7	????20.4
			Wax oil	????10.6	????11.5
Coke	????34.3	????38.3

Table 3

The embodiment numbering	????1	????2
			Coker gasoline density (20 ℃), gram per centimeter 3The bromine valency, gBr/100g sulphur, ppm	????0.7589 ????26.4 ????606	????0.7558 ????27.3 ????584
Coker gas oil density (20 ℃), gram per centimeter 3The bromine valency, the gBr/100g condensation point, ℃ aniline point, ℃ 10% carbon residue, heavy % sulphur, ppm	????0.8982 ????18.4 ????-26 ????35.8 ????0.16 ????842	????0.8932 ????17.9 ????-18 ????41.3 ????0.04 ????819
			Wax tailings density (20 ℃), gram per centimeter 3Carbon residue, heavy % sulphur, heavy %	????1.063 ????0.19 ????0.56	????1.135 ????0.90 ????0.38
Pin charred ashes part, heavy % fugitive constituent, heavy % sulphur content, heavy % true density, gram per centimeter 3CTE,×10 -6/℃	????0.06 ????9.6 ????0.39 ????2.184 ????2.57	????0.05 ????9.2 ????0.33 ????2.140 ????2.49

Claims (6)

1, a kind of from long residuum production acicular petroleum coke method, it is characterized in that long residuum and coking recycle oil are together after relaxing thermal transition, the lighting end that generates comes along with coking oil gas and separates, remaining last running enters coke drum after the process furnace heating, the coke that generates is stayed in the coke drum, coking oil gas obtains gas, gasoline, diesel oil, wax oil and turning oil through fractionation, and wherein turning oil and long residuum relax thermal transition together.

2, according to the method for claim 1, it is characterized in that described long residuum is the long residuum of any crude oil, and with arbitrary proportion blended long residuum.

3, according to the method for claim 1, it is characterized in that relaxing 370 ℃～510 ℃ of thermal transition furnace outlet temperature, water injection rate accounts for 0～20 heavy % of charging, and pressure is 0～1.0 MPa, 2～180 seconds residence time.

4, according to the method for claim 1, it is characterized in that described delay coking heating furnace is operating as the alternating temperature operation, the process furnace extent of alternating temperature is 430 ℃～520 ℃.

5,, it is characterized in that described coke tower top pressure is 0.10～3.0 MPa according to the method for claim 1.

6, according to the method for claim 1, the weight ratio that it is characterized in that described turning oil and long residuum is 0.2～1.0: 1.