阅读说明：本技术 一种焦化污油密闭回炼的工艺 (Coking dirty oil closed recycling process ) 是由 林维华 荆亮 李卫 郭克礼 于 2021-10-08 设计创作，主要内容包括：本发明提供了一种焦化污油密闭回炼的工艺,改进焦化污油回炼工艺,去除甩油罐组,加设污油蒸发塔,充分利用装置余热给含水污油持续加温,根据工艺运行的不同阶段灵活调整污油回炼,使装置保持加工量最大化,装置能耗最低化,实现含水污油本装置内密闭回炼。该工艺可充分利用装置低温热源,实现焦化装置含水污油在本装置内密闭回炼。取消了传统工艺配套的甩油罐组,及相应的加温、消防设施,减少了设备投资,降低了装置的占地面积,同时减少原有的甩油加温蒸汽消耗,降低了装置能耗。(The invention provides a process for closed remilling of coking dirty oil, which is characterized in that the process for closed remilling of coking dirty oil is improved, an oil throwing tank group is removed, a dirty oil evaporation tower is additionally arranged, the waste heat of a device is fully utilized to continuously heat water-containing dirty oil, the remilling of the dirty oil is flexibly adjusted according to different stages of process operation, the processing amount of the device is maximized, the energy consumption of the device is minimized, and the closed remilling of the water-containing dirty oil in the device is realized. The process can fully utilize the low-temperature heat source of the device, and realize the closed recycling of the water-containing sump oil of the coking device in the device. The oil throwing tank set matched with the traditional process and corresponding heating and fire fighting facilities are eliminated, the equipment investment is reduced, the floor area of the device is reduced, meanwhile, the consumption of the original oil throwing heating steam is reduced, and the energy consumption of the device is reduced.)

1. A process for closed refining of coking dirty oil is characterized by comprising the following steps: the process comprises the following steps:

a: raw material sump oil is stored in a cold coke water sump oil tank (1), and an oil outlet pipe of the cold coke water sump oil tank is provided with a cold coke water sump oil pump (4); a sump oil evaporation tower (2) is arranged in the fractionating tower area, an oil outlet of a coke cooling water sump oil pump is connected with two oil outlet pipes, one oil outlet pipe is connected with the sump oil evaporation tower, the other oil outlet pipe is connected with a cooler (5), and water-containing sump oil generated by a coke cooling water system is heated by heat exchange and then enters the sump oil evaporation tower;

b: a dirty oil and diesel oil heat exchanger (6) is arranged, the generated oil stain and diesel oil before air cooling are subjected to heat exchange through the dirty oil and diesel oil heat exchanger, the temperature is raised to 130 ℃, and then the oil stain and the diesel oil enter a dirty oil evaporation tower;

c: a tower bottom circulating pump (7) is arranged at the bottom of the dirty oil evaporation tower, an oil inlet of the tower bottom circulating pump is connected with a tower bottom outlet of the dirty oil evaporation tower, an oil outlet of the tower bottom circulating pump is connected with two oil outlet pipes, one oil outlet pipe exchanges heat with low-temperature heat sources such as diesel oil or top circulation and then returns to the dirty oil evaporation tower for internal circulation, and the other oil outlet pipe is connected to a wax oil feeding line of the fractionating tower and returns to the fractionating tower for recycling;

d: circulating oil at the bottom of the dirty oil evaporation tower is always in a circulating state, the device diesel oil low-temperature heat is transferred into an evaporation system, the dirty oil containing water in the dirty oil evaporation tower is subjected to preliminary evaporation and dehydration, the effect of a heat energy accumulator is achieved, the low-temperature waste heat of the device is fully recovered, and the dirty oil gradually meets the recycling requirement;

e: a gas-phase communication line arranged on the top of the dirty oil evaporation tower is connected to a meteorological line of the raw material buffer tank (3) and enters a fractionating tower, moisture in the oil product is heated and vaporized and enters the fractionating tower, and finally, the moisture is condensed and discharged in a reflux tank on the top of the fractionating tower;

f: according to the change of oil throwing amount caused by the periodical tower replacement operation of the coke tower and the periodical change of heat of the fractionating tower, the dirty oil evaporation tower is used as a device for receiving and storing the water-containing dirty oil generated by the device, and the dirty oil evaporation tower plays roles of heat buffering of the device and water-containing dirty oil buffering through periodical adjustment and remill;

g: the recycling amount and the recycling time of the dirty oil are adjusted according to the running condition of the device;

h: an external oil throwing line is directly arranged in a refining line of the fractionating tower, and the sump oil at the high temperature of 280 ℃ in the later preheating stage can directly enter the fractionating tower for refining;

i: the dirty oil main pipe is connected to the cooler back before advancing dirty oil evaporating tower, is connected with two way connecting pipes, advances emergent jar as the flow that emergent shutdown of device or accident condition dirty oil got rid of outside and get into emergent jar all the way, and another way connects to raw materials and advances device raw materials line, and if dirty oil delivery volume is great outward, also can send the dirty oil outside to the raw materials line after the cooler to carry out the remill, and this remill operation will be noted and is adopted the small amount of remills, prevents to contain a large amount of dirty oil and influences the normal production of device.

2. The process for closed refining of coking dirty oil according to claim 1, characterized in that: in the step G, the temperature difference of a radiation inlet and a radiation outlet of the heating furnace is large, the load of the heating furnace is large, the recycling is not suitable in the stage, the stage of heat storage and evaporation dehydration of the evaporation tower is adopted in the stage, the heat of the fractionating tower is sufficient along with the completion of preheating, the load of the heating furnace is reduced, the recycling of dirty oil can be increased by feeding the dirty oil into a wax oil upper return line, and the dirty oil is further evaporated, dehydrated and recycled in the fractionating tower; before the next coke tower is replaced, the dirty oil containing water in the evaporation tower is recycled to the lowest liquid level so as to store a large amount of water-containing thrown oil during the next tower replacement, thereby realizing the purposes of periodically temporarily storing the evaporation tower and recycling the dirty oil through a fractionation system.

3. The process for closed refining of coking dirty oil according to claim 1, characterized in that: and the bottom circulating pump is a chemical process pump or an AY oil pump with the flow rate of 25-30 m/h and the head of 60 m.

4. The process for closed refining of coking dirty oil according to claim 1, characterized in that: the dirty oil and diesel oil heat exchanger is a shell-and-tube heat exchanger with the area of 55-70 square meters.

5. The process for closed refining of coking dirty oil according to claim 1, characterized in that: the pipe diameter of a connecting pipeline between the devices is set to be DN 80-100; the pipeline material of dirty oil main pipe dirty oil inlet evaporation tower line sets up to Cr5Mo material, and the other pipelines set up to carbon steel seamless steel pipe.

Technical Field

The invention relates to a coking dirty oil recycling process, in particular to a coking dirty oil closed recycling process.

Background

In the oil refining industry, a delayed coking device is one of important means for treating the lightening of heavy residual oil, is a main means for improving the yield of light oil and producing petroleum coke in an oil refinery, and plays an important role in the oil refining industry in China. The production process of the delayed coking device comprises two parts of coking and decoking, wherein the coking is continuous operation, the decoking is intermittent operation, and the production scale comprises a one-furnace two-tower (coke tower) flow, a two-furnace four-tower flow, and the switching period of each tower is generally 24 hours.

The process comprises the steps of blowing steam and emptying, injecting water and cooling coke, decoking, preheating and the like before the coke tower is put into use due to the periodic switching operation of the coke tower, so that the old coke tower reaches the use condition, partial dirty oil can be generated in the steam blowing and emptying, old tower preheating and coke cooling water system, the dirty oil is different in quality, temperature and generation time period and contains partial water, so that the partial dirty oil is difficult to recycle compared with the conventional oil refining process, the partial dirty oil is thrown into an oil throwing tank area after being cooled by cold discharge in the conventional process, and the partial dirty oil is returned to a raw material line feeding device for recycling by a mechanical pump after being settled, heated, evaporated and dehydrated.

The process has the following disadvantages:

(1) the dirty oil that produces need be got rid of outward after the cooling and get into and get rid of the oil tank, has increased the cooling water load, and the jar district heats and has increased steam consumption, causes the device energy consumption to increase.

(2) Two oil throwing tank sets are needed, so that the occupied area of the device is greatly increased, and the equipment investment and the operation management cost are increased.

(3) The oil products with different temperature levels enter the same tank set after being cooled, and the heat energy of the high-quality oil products cannot be recycled.

(4) The oil throwing tank group is a normal-pressure container, VOC (volatile organic compounds) odor generated by heating in the tank is difficult to treat, the current environmental protection requirement is more and more strict, and the odor on the top of the oil throwing tank cannot meet the environmental protection requirement.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a process for closed refining of coking dirty oil, which is characterized in that the process for closed refining of coking dirty oil is improved, an oil throwing tank group is removed, a dirty oil evaporation tower is additionally arranged, the waste heat of a device is fully utilized to continuously heat water-containing dirty oil, the refining of dirty oil is flexibly adjusted according to different stages of process operation, the processing amount of the device is maximized, the energy consumption of the device is minimized, and the closed refining of the water-containing dirty oil in the device is realized.

The invention discloses a process for closed refining of coking dirty oil, which is characterized by comprising the following steps: the process comprises the following steps:

a: storing raw material sump oil into a cold coke water sump oil tank, wherein an oil outlet pipe of the cold coke water sump oil tank is provided with a cold coke water sump oil pump; the method comprises the following steps that a sump oil evaporation tower is arranged in a fractionating tower area, an oil outlet of a coke cooling water sump oil pump is connected with two oil outlet pipes, one oil outlet pipe is connected with the sump oil evaporation tower, the other oil outlet pipe is connected with a cooler, and water-containing sump oil generated by a coke cooling water system enters the sump oil evaporation tower after being subjected to heat exchange and temperature rise;

b: a dirty oil and diesel oil heat exchanger is arranged, the generated oil stain and diesel oil before air cooling are subjected to heat exchange through the dirty oil and diesel oil heat exchanger to be heated to 130 ℃, and then the oil stain and the diesel oil enter a dirty oil evaporation tower;

c: the bottom of the dirty oil evaporation tower is provided with a tower bottom circulating pump, an oil inlet of the tower bottom circulating pump is connected with a tower bottom outlet of the dirty oil evaporation tower, an oil outlet of the tower bottom circulating pump is connected with two oil outlet pipes, one oil outlet pipe exchanges heat with low-temperature heat sources such as diesel oil or top circulation and then returns to the dirty oil evaporation tower for internal circulation, and the other oil outlet pipe is connected to a wax oil feeding line of the fractionating tower and returns to the fractionating tower for recycling;

d: circulating oil at the bottom of the dirty oil evaporation tower is always in a circulating state, the device diesel oil low-temperature heat is transferred into an evaporation system, the dirty oil containing water in the dirty oil evaporation tower is subjected to preliminary evaporation and dehydration, the effect of a heat energy accumulator is achieved, the low-temperature waste heat of the device is fully recovered, and the dirty oil gradually meets the recycling requirement;

e: the top of the dirty oil evaporation tower is provided with a gas-phase communication line which is connected to a meteorological line of the raw material buffer tank and enters a fractionating tower, moisture in the oil product is heated and vaporized and enters the fractionating tower, and finally, the moisture is condensed and discharged in a reflux tank at the top of the fractionating tower;

f: according to the change of oil throwing amount caused by the periodical tower replacement operation of the coke tower and the periodical change of heat of the fractionating tower, the dirty oil evaporation tower is used as a device for receiving and storing the water-containing dirty oil generated by the device, and the dirty oil evaporation tower plays roles of heat buffering of the device and water-containing dirty oil buffering through periodical adjustment and remill;

g: the recycling amount and the recycling time of the dirty oil are adjusted according to the running condition of the device;

h: an external oil throwing line is directly arranged in a refining line of the fractionating tower, and the sump oil at the high temperature of 280 ℃ in the later preheating stage can directly enter the fractionating tower for refining;

i: the dirty oil main pipe is connected to the cooler back before advancing dirty oil evaporating tower, is connected with two way connecting pipes, advances emergent jar as the flow that emergent shutdown of device or accident condition dirty oil got rid of outside and get into emergent jar all the way, and another way connects to raw materials and advances device raw materials line, and if dirty oil delivery volume is great outward, also can send the dirty oil outside to the raw materials line after the cooler to carry out the remill, and this remill operation will be noted and is adopted the small amount of remills, prevents to contain a large amount of dirty oil and influences the normal production of device.

Furthermore, in the step G, the temperature difference between the radiation inlet and the radiation outlet of the heating furnace is large, the load of the heating furnace is large, the recycling is not suitable in the stage, the heat is stored in the evaporation tower and the evaporation and dehydration are performed in the stage, along with the completion of preheating, the heat of the fractionating tower is sufficient, the load of the heating furnace is reduced, the recycling of the dirty oil can be increased through a dirty oil inlet wax oil upper return line, and the dirty oil is further evaporated, dehydrated and recycled in the fractionating tower; before the next coke tower is replaced, the dirty oil containing water in the evaporation tower is recycled to the lowest liquid level so as to store a large amount of water-containing thrown oil during the next tower replacement, thereby realizing the purposes of periodically temporarily storing the evaporation tower and recycling the dirty oil through a fractionation system.

Further, the bottom circulating pump is a chemical process pump or an AY oil pump with the flow rate of 25-30 m/h and the head of 60 m.

Further, the dirty oil and diesel oil heat exchanger is a shell-and-tube heat exchanger with the area of 55-70 square meters.

Furthermore, the pipe diameter of a connecting pipeline between the devices is set to be DN 80-100; the pipeline material of dirty oil main pipe dirty oil inlet evaporation tower line sets up to Cr5Mo material, and the other pipelines set up to carbon steel seamless steel pipe.

The invention has the beneficial effects that:

(1) the process can fully utilize the low-temperature heat source of the device, and realize the closed recycling of the water-containing sump oil of the coking device in the device.

(2) An oil throwing tank set matched with the traditional process and corresponding heating and fire-fighting facilities are eliminated, the equipment investment is reduced, and the occupied area of the device is reduced. Meanwhile, the consumption of the original oil-throwing heating steam is reduced, and the energy consumption of the device is reduced.

(3) The operation flexibility of the device and the adjustment flexibility of the fractionation system are increased, different sections are selected for carrying out the back smelting operation, the bottleneck of restriction of heating furnace load when the heat source is insufficient in the preheating and steam blowing stages of the device is eliminated, and the processing capacity of the device is kept to be maximized. The action and the space of the heat accumulator of the evaporation tower are fully utilized, and the fluctuation and the influence on the fractionating tower caused by periodic operation are effectively relieved.

(4) The diesel oil low-temperature heat source is fully recycled and used for heating the dirty oil of the evaporation tower, the temperature of the diesel oil entering the air cooling is reduced, the power consumption of the diesel oil in the air cooling is reduced, and the energy consumption of the device is reduced.

(5) The cooling water consumption of cold drainage when the original dirty oil is thrown outwards is reduced.

(6) The discharge of volatile gas of the original oil throwing tank set is reduced, and the VOC treatment in a factory is facilitated to meet the environmental protection requirement.

Drawings

FIG. 1 is a schematic flow diagram of a conventional dirty oil recycle process for a coker;

FIG. 2 is a schematic diagram of the process flow of the present invention.

In the figure: 1 cold coke water sump oil tank, 2 sump oil evaporation tower, 3 raw materials buffer tank, 4 cold coke water sump oil pump, 5 cooler, 6 diesel oil sump oil heat exchanger, 7 tower bottom circulating pump.

Detailed Description

The invention is further described with reference to the following figures and examples.

As shown in the figures 1 and 2, in the invention, an oil throwing tank group and a corresponding heating facility are cancelled, a sump oil evaporation tower 2 is additionally arranged in a fractionating tower area of the device, the original coke cooling water sump oil is stored in a coke cooling water sump oil tank 1 and is pumped out through a coke cooling water sump oil pump 4, an oil outlet of the coke cooling water sump oil pump 4 is connected with two pipelines, one pipeline is connected to the sump oil evaporation tower 2, the other pipeline is connected to a cooler 5, and the device blows steam to be emptied, preheats and the water-containing sump oil generated by a coke cooling water system enters the sump oil evaporation tower 2 after being heated through heat exchange.

And a dirty oil and diesel oil heat exchanger 6 is additionally arranged, the generated oil stain and diesel oil before air cooling are subjected to heat exchange through the dirty oil and diesel oil heat exchanger 6, the temperature is raised to 130 ℃, and then the oil stain and the diesel oil enter a dirty oil evaporation tower 2.

The bottom of the dirty oil evaporation tower 2 is provided with a tower bottom circulating pump 7, an oil inlet of the tower bottom circulating pump 7 is connected with a tower bottom outlet of the dirty oil evaporation tower 2, an oil outlet of the tower bottom circulating pump 7 is connected with two oil outlet pipes, one oil outlet pipe exchanges heat with low-temperature heat sources such as diesel oil or top circulation and then returns to the dirty oil evaporation tower 2 for internal circulation, and the other oil outlet pipe is connected to a wax oil feeding line of the fractionating tower and returns to the fractionating tower for recycling.

The circulating oil at the bottom of the sump oil evaporation tower 2 is always kept in a circulating state, a diesel oil low-temperature heat transfer device is arranged in an evaporation system, the sump oil evaporation tower 2 contains water sump oil to be subjected to preliminary evaporation and dehydration, the effect of a heat energy accumulator is achieved, low-temperature waste heat of the device is fully recovered, the sump oil evaporation tower 2 is equivalent to a heat accumulator, a high-temperature heat source for blowing air and emptying, preheating and throwing oil is absorbed simultaneously, heat is stored continuously, and the sump oil gradually meets the requirement of recycling.

The top of the dirty oil evaporation tower 2 is provided with a gas phase communication line which is connected to a meteorological line of the raw material buffer tank 3 and enters a fractionating tower, moisture in the oil product is heated and vaporized and enters the fractionating tower, and finally, the moisture is condensed and discharged in a reflux tank at the top of the fractionating tower.

According to the change of the oil throwing amount caused by the periodical tower replacement operation of the coke tower and the periodical change of the heat of the fractionating tower, the dirty oil evaporation tower 2 is used as a device for receiving and storing the water-containing dirty oil generated by the device, and the dirty oil evaporation tower 2 plays roles of buffering the heat of the device and buffering the water-containing dirty oil through periodical adjustment and remill;

the recycling amount and the recycling time of the dirty oil are adjusted according to the running condition of the device; the temperature difference of a radiation inlet and a radiation outlet of the heating furnace is large, the load of the heating furnace is large, the recycling is not suitable in the stage, the heat is stored in the evaporation tower and the evaporation and dehydration are performed in the stage, along with the completion of preheating, the heat of the fractionating tower is sufficient, the load of the heating furnace is reduced, the recycling of dirty oil can be increased by feeding the dirty oil into a wax oil upper return line, and the dirty oil is further evaporated, dehydrated and recycled in the fractionating tower; before the next coke tower is replaced, the dirty oil containing water in the evaporation tower is recycled to the lowest liquid level so as to store a large amount of water-containing thrown oil during the next tower replacement, thereby realizing the purposes of periodically temporarily storing the evaporation tower and recycling the dirty oil through a fractionation system.

An external oil throwing line is directly arranged on a refining line of the fractionating tower, and the sump oil at the high temperature of 280 ℃ in the later preheating stage can directly enter the fractionating tower for refining.

The dirty oil main pipe is connected to the cooler back before advancing dirty oil evaporating tower, is connected with two way connecting pipes, advances emergent jar as the flow that emergent shutdown of device or accident condition dirty oil got rid of outside and get into emergent jar all the way, and another way connects to raw materials and advances device raw materials line, and if dirty oil delivery volume is great outward, also can send the dirty oil outside to the raw materials line after the cooler to carry out the remill, and this remill operation will be noted and is adopted the small amount of remills, prevents to contain a large amount of dirty oil and influences the normal production of device.

When the double-column double-row thin film carbon dioxide distillation tower is used, a coking device of 60 ten thousand tons per year is taken as an example, the volume of a tower body is set to be a vertical tower with 100m for thin film carbon dioxide distillation, and due to the fact that no flow distribution precision requirement exists, a herringbone baffle plate or regular packing is adopted in the structure in the tower.

The bottom circulating pump can select a chemical process pump or an AY oil pump with the flow rate of 25-30m3/h and the head of 60m according to the requirements of the produced oil pollution amount and pressure.

And a bottom circulating pump selects a chemical process pump or an AY oil pump with the flow rate of 25-30 m/h and the head of 60 m.

The dirty oil and diesel oil heat exchanger is a shell-and-tube heat exchanger with the area of 55-70 square meters.

The pipe diameter of a connecting pipeline between the devices is set to be DN 80-100; the pipeline material of dirty oil main pipe dirty oil inlet evaporation tower line sets up to Cr5Mo material, and the other pipelines set up to carbon steel seamless steel pipe.