阅读说明：本技术 一种沸腾床渣油加氢裂化装置未转化油换热器的清洗方法 (Method for cleaning unconverted oil heat exchanger of fluidized bed residual oil hydrocracking device ) 是由 彭光勤 马强 尚纪兵 汪文强 于 2020-06-28 设计创作，主要内容包括：本发明涉及一种沸腾床渣油加氢裂化装置未转化油换热器的清洗方法,属于炼油领域。本发明所述清洗方法为：将重芳烃加热至130-150℃,加热后的重芳烃进入螺旋板换热器,重芳烃的流量为＞80t/h。本发明利用了重芳烃对换热器内焦块有很好的溶解及粉化作用,无需拆卸本体大盖即可清洗,大大节约了清洗的费用。(The invention relates to a method for cleaning a heat exchanger of unconverted oil of a boiling bed residual oil hydrocracking device, belonging to the field of oil refining. The cleaning method comprises the following steps: heating the heavy aromatic hydrocarbon to 130-150 ℃, and enabling the heated heavy aromatic hydrocarbon to enter a spiral plate heat exchanger, wherein the flow rate of the heavy aromatic hydrocarbon is more than 80 t/h. The invention utilizes the good dissolving and powdering effect of heavy aromatics on coke blocks in the heat exchanger, and can be cleaned without disassembling the large cover of the body, thereby greatly saving the cleaning cost.)

1. A method for cleaning a heat exchanger of unconverted oil of a boiling bed residual oil hydrocracking device is characterized by comprising the following steps: the cleaning method comprises the following steps: heating the heavy aromatic hydrocarbon to 130-150 ℃, and enabling the heated heavy aromatic hydrocarbon to enter a spiral plate heat exchanger, wherein the flow rate of the heavy aromatic hydrocarbon is more than 80 t/h.

2. The method for cleaning the unconverted oil heat exchanger of the ebullated-bed residue hydrocracking unit as set forth in claim 1, wherein: and the heated heavy aromatic hydrocarbon enters the spiral plate heat exchanger from an unconverted oil inlet and a raw material residual oil or low-temperature hot water inlet of the spiral plate heat exchanger, or the heated heavy aromatic hydrocarbon enters the spiral plate heat exchanger from an unconverted oil outlet and a raw material residual oil or low-temperature hot water outlet of the spiral plate heat exchanger.

3. The method for cleaning the unconverted oil heat exchanger of the ebullated-bed residue hydrocracking unit as set forth in claim 2, wherein: and (3) the heavy aromatic hydrocarbon flowing out of the spiral plate heat exchanger enters a basket filter, returns to the spiral plate heat exchanger, is circularly cleaned until the blockage in the spiral plate heat exchanger is dissolved and pulverized, and is brought into the basket filter.

4. The method of cleaning the unconverted oil heat exchanger of the ebullated bed resid hydrocracking unit as set forth in claim 3, wherein: heavy aromatics are by-products produced by upstream aromatics complexes.

5. The method of cleaning the unconverted oil heat exchanger of the ebullated bed resid hydrocracking unit as set forth in claim 4, wherein: when the heavy aromatics cannot be used, the heavy aromatics that cannot be used are discharged to a fractionation system.

Technical Field

The invention relates to a method for cleaning a heat exchanger of unconverted oil of a boiling bed residual oil hydrocracking device, belonging to the field of oil refining.

Background

In recent years, with the trend of crude oil upgrading and deterioration, the demand of light oil products in the market is increasing and environmental regulations are becoming stricter, and the efficient conversion and clean utilization of heavy oil, especially residual oil, become the focus of attention of the world refining industry. The boiling bed residual oil hydrogenation process is accepted by various oil refineries due to the advantages of wide range of processing raw materials, small pressure drop of a reactor, good heat and mass transfer effects and the like. But because of the characteristics of poor raw material property, high operation temperature, high conversion rate and the like, a series of problems of coking, blockage and the like can be generated in the operation process. Wherein coking plugging of the unconverted oil export heat exchanger has become one of the major problems limiting long-term stable operation of ebullated bed residue hydrotreaters. The residual oil is a colloid system consisting of a dispersed phase and a continuous phase, the vacuum residual oil exists in the form of four components of saturated hydrocarbon, aromatic hydrocarbon, colloid and asphaltene, asphaltene precipitation and deposition are not normally generated, but after the reaction of the vacuum residual oil in the fluidized bed reactor, the stable colloid system is destroyed, and the asphaltene precipitation and deposition in unconverted oil are caused. Asphaltene in unconverted oil is precipitated and then attached to the inner wall of the heat exchanger and gradually condensed into coke at high temperature, so that the heat exchange efficiency and the circulation capacity of the heat exchanger are greatly reduced. The unconverted oil heat exchanger generally exchanges heat with raw material residual oil, and after the heat exchange efficiency is reduced, the temperature of the raw material residual oil entering a high-temperature exchange and heating furnace is reduced, so that the gas consumption is increased; on the other hand, the temperature of the unconverted oil-out device is increased, and the safety of the downstream device or the tank field is affected. In addition, the situation of unsmooth delivery can occur after the circulation capacity of the unconverted oil heat exchanger is reduced, so that the liquid level at the bottom of the pressure reduction tower is increased, and the reaction yield reduction operation can be caused in severe cases.

The non-converted oil heat exchanger at the vacuum tower bottom of the boiling bed residual oil hydrocracking device in foreign countries generally uses a common shell-and-tube heat exchanger, and the main problems in the operation are as follows: the service cycle is short, generally about 1 week, and the cut-out heat exchanger needs to be subjected to core pulling and high-pressure water gun cleaning and chemical cleaning.

Disclosure of Invention

The present invention solves the above problems by a new cleaning method.

The invention provides a cleaning method of a non-converted oil heat exchanger of a boiling bed residual oil hydrocracking device, which comprises the following steps: heating the heavy aromatic hydrocarbon to 130-150 ℃, and enabling the heated heavy aromatic hydrocarbon to enter a spiral plate heat exchanger, wherein the flow rate of the heavy aromatic hydrocarbon is more than 80 t/h.

The invention preferably selects that the heated heavy aromatic hydrocarbon enters the spiral plate heat exchanger from an unconverted oil inlet and a raw material residual oil or low-temperature hot water inlet of the spiral plate heat exchanger, or the heated heavy aromatic hydrocarbon enters the spiral plate heat exchanger from an unconverted oil outlet and a raw material residual oil or low-temperature hot water outlet of the spiral plate heat exchanger.

The heavy aromatic hydrocarbon flowing out of the spiral plate heat exchanger enters the basket filter, returns to the spiral plate heat exchanger, is circularly cleaned until the blockage in the spiral plate heat exchanger is dissolved and pulverized and is carried into the basket filter.

The present invention preferably employs heavy aromatics as a by-product from an upstream aromatics complex.

The present invention preferably discharges unusable heavy aromatics to a fractionation system when the unusable heavy aromatics cannot be used.

The invention has the beneficial effects that:

even if the existing unconverted oil heat exchanger of the boiling bed residual oil hydrocracking device is a very advanced spiral plate heat exchanger at present, when the device runs for about 20 days on line, the large body cover is required to be disassembled, high-pressure water gun cleaning and chemical cleaning are carried out, frequent cleaning increases the cost, the surrounding environment is polluted, equipment, production and safety are greatly influenced by disassembling and assembling the large body cover and cleaning back and forth, the service life of the equipment is shortened, the production load is limited, the safety risk is increased, and the specific cleaning cost is as follows: the cleaning cost of each heat exchanger is as high as 19 ten thousand yuan, and the cleaning cost of one heat exchanger is more than 19 ten thousand yuan. The cleaning method of the invention utilizes the good dissolving and powdering effect of heavy aromatics on coke blocks in the heat exchanger, and can clean the coke blocks without disassembling the large cover of the body, thereby greatly saving the cleaning cost, and the specific cleaning cost is as follows: the cleaning cost of the high-pressure water gun cleaning and chemical cleaning is far lower than that of the high-pressure water gun cleaning and chemical cleaning, the heat exchanger cleaned by heavy aromatics can recover the same flow capacity and heat exchange effect as the high-pressure water gun cleaning and chemical cleaning, in addition, the cleaning method of the invention is utilized to clean the heat exchanger, and simultaneously, the influence of the back-and-forth disassembly of the large cover of the body and the cleaning on the production and the safety is eliminated, thereby providing powerful guarantee for the long-period and high-load operation of the boiling bed residual oil hydrocracking device.

Detailed Description

The following non-limiting examples are presented to enable those of ordinary skill in the art to more fully understand the present invention and are not intended to limit the invention in any way.