CN106642165B

CN106642165B - A kind of treatment method of volatile organic compounds in refinery

Info

Publication number: CN106642165B
Application number: CN201710059016.3A
Authority: CN
Inventors: 宫超; 张瑞波; 杨玉敏; 刘金龙; 何庆生; 宋业恒; 闫鸿飞; 时东兴; 李克文; 王建
Original assignee: Sinopec Engineering Group Co Ltd
Current assignee: Sinopec Engineering Group Co Ltd; Sinopec Energy Management Co Ltd
Priority date: 2017-01-23
Filing date: 2017-01-23
Publication date: 2021-06-29
Anticipated expiration: 2037-01-23
Also published as: CN106642165A

Abstract

The invention provides a treatment method of Volatile Organic Compounds (VOCs) in a refinery, which solves the problems of high cost, easy corrosion of equipment, secondary pollution and the like of a VOCs combustion treatment process. The processing method comprises the following steps: volatile organic matters follow the main windIntroducing the mixture into a catalytic cracking regenerator, and carrying out combustion reaction under the combustion supporting of coke on a regenerated catalyst, wherein the temperature of the combustion reaction is 650-750 ℃, and the concentration of a volatile organic compound before entering the regenerator is less than or equal to 30000mg/m³. The mode of introducing the VOCs into the regenerator is arbitrary, for example: the VOCs are connected into a main air pipeline of an FCC regenerator, mixed with main air, firstly enter a gas distributor, fully and uniformly mixed with the main air (air), and then enter the regenerator for combustion treatment; alternatively, the VOCs are fed directly into the regenerator through the backup fuel inlet and then normally combusted in the regenerator.

Description

Method for treating volatile organic compounds in refinery

Technical Field

The invention relates to the field of petrochemical industry, in particular to a method for treating volatile organic compounds in a refinery.

Background

Volatile Organic Compounds (VOCs) are the primary precursor of photochemical pollution and are one of the important pollutants affecting the quality of urban and regional environments. Refinery enterprises may emit a certain amount of Volatile Organic Compounds (VOCs) during production, transportation, and sale. The discharged volatile organic compounds not only can affect the environment and cause harm to human health, but also can cause great economic loss of enterprises. Controlling the emission of volatile organic compounds and treating the emitted volatile organic compounds become an important task for enterprises to save energy, reduce emission, improve economic benefits and protect environment.

The emission sources of the VOCs of the refining enterprises are mainly divided into leakage emission sources and dissipation emission sources. The discharged VOCs have the characteristics of multiple pollutant types, wide distribution of discharge points, high quantification difficulty and the like, and the discharge of the VOCs mainly comes from a crude oil and product storage tank, device leakage, wastewater treatment, boiler flue gas, a combustion process, process heating, a process unit, a loading and unloading and cooling tower and the like. The treatment method of VOCs is divided into a recovery method and a removal method according to the state of the treated tail gas. The VOCs recovery technology mainly comprises a membrane separation method, an adsorption method, a condensation method, an absorption method and the like, the recovered organic pollutants need to be further treated, the process is relatively complex, the cost is higher, and secondary pollution to the environment is easily caused. The selectivity and separation effect of the membrane separation method and the adsorption method are poor; the condensation and absorption processes are energy intensive and require a certain amount of absorbent. The elimination technology mainly comprises a combustion method (thermal combustion/catalytic combustion), a photocatalytic oxidation method, a biological method and the like, and the principle is that organic matters are converted into water and CO under the action of light, a thermal catalyst, microorganisms and the like through chemical or biological reaction₂And the like. In contrast, direct elimination removes small amounts of water and the greenhouse gas CO₂Besides, the method does not cause secondary pollution, and the treatment is most thorough, and the removal rate can reach more than 96 percent, so that the method is more universal.

The combustion method for treating the VOCs has the characteristics of simple process and high purification efficiency, but the combustion device is independently arranged at present for treating the VOCs, so that the problems of relatively high running cost, easy corrosion of equipment, secondary pollution and the like, particularly the cost problem, are brought to enterprises, the survival problem of the enterprises is related, and whether the enterprises actively treat the VOCs pollution problem is directly determined.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The invention aims to provide a treatment method of volatile organic compounds, which solves the problems of high cost, easy corrosion of equipment, secondary pollution and the like of a VOCs combustion treatment process.

In order to achieve the above purpose, the invention provides the following technical scheme:

refining deviceThe method for treating the volatile organic matters in the factory comprises the steps of introducing the volatile organic matters into a catalytic cracking regenerator, and carrying out combustion reaction under the combustion supporting action of coke on a regenerated catalyst, wherein the temperature of the combustion reaction is 690-750 ℃, and the concentration of the volatile organic matters before entering the regenerator is not more than 30000mg/m³。

The main wind mainly refers to air and can also be oxygen with various purities.

The mode of introducing the VOCs into the regenerator is arbitrary, for example:

the VOCs are connected into a main air pipeline of the FCC regenerator, mixed with the main air and then firstly enter a gas distributor to ensure that the VOCs and the main air (air) are fully and uniformly mixed, and then enter the regenerator for combustion treatment. The waste gas after burning enters the original environment-friendly devices for dust removal, desulfurization, denitration and the like, and is exhausted after meeting the standard.

Alternatively, the VOCs are fed directly into the regenerator through the backup fuel inlet and then normally combusted in the regenerator.

Compared with the prior art, the main innovation point of the invention is that the existing equipment of a refinery, namely a catalytic cracking regenerator and regenerated flue gas treatment equipment, is fully utilized, and one object has multiple purposes, so that the problems of high cost, secondary pollution, equipment corrosion and the like of the common VOCS treatment method are solved. The details are as follows.

The invention relates to a Fluid Catalytic Cracking (FCC) regenerator which is one of necessary devices of the existing petroleum catalytic cracking process, and the main function of the FCC regenerator is to circularly regenerate a catalyst used for catalytic cracking.

More importantly, the method of the invention adopts the FCC regenerator to treat the VOCs without any adverse effect on the regeneration process of the catalyst, i.e. the VOCs and the regenerated catalyst can simultaneously carry out combustion reaction in the same FCC regenerator to respectively complete the combustion of the VOCs and the regeneration of the catalyst.

In addition, as the volatile organic compounds with specific temperature and certain concentration are selected, the heat generated by combustion of the VOCs can be ignored compared with the regeneration heat of the catalyst, and the heat extraction equipment does not need to be modified.

In summary, the processing method of the present invention has the following features:

1. the cost brought by adding equipment is saved.

2. VOCs can coexist with the catalyst and carry out combustion reaction at the same time, namely, the invention has no any substantial influence on the regeneration of the catalyst.

The above method is only the subject of the present invention, and each step or process condition thereof may be further modified, for example:

preferably, the concentration of the volatile organic compounds before entering the regenerator is no more than 30000mg/m³Preferably 25000mg/m or less³Preferably ≤ 20000mg/m³Preferably 16000mg/m³。

Effectively controlling the concentration of VOCs entering the regenerator, not only realizing the high-efficient removal of VOCs, but also not generating any adverse effect on the normal production operation of the original FCC regenerator, only when VOCs just start to enter the regenerator and the concentration of the VOCs is higher (the concentration after mixing with the main air is 20000 mg/m)³And above), the temperature in the regenerator slightly rises, but quickly returns to normal. In addition, when the concentration of VOCs reaches 20000mg/m³In the above case, it is preferable to recover high-concentration VOCs by a diesel absorption process and then perform the internal combustion treatment in the FCC regenerator. Under normal production conditions, the high-concentration VOCs are rapidly combusted in the regenerator to generate a small amount of carbon dioxide and water, and the concentration of the VOCs before entering the regenerator is controlled within a certain range, namely the concentration of the VOCs is not higher than 20000mg/m³The generated relatively small amount of water vapor does not have substantial influence on the activity and stability of the regenerator catalyst, the reaction heat is small, the temperature does not fluctuate greatly, the original heat taking facility does not need to be modified, and the danger of combustion and explosion caused by high concentration of VOCs is avoided.

In order to increase the removal rate of the volatile organic compounds, the temperature of the combustion reaction is preferably 650-.

Generally, a main catalytic cracking unit of a refinery is followed by a flue gas treatment system to treat SOx and NOx formed in a regenerator by compounds such as sulfur and nitrogen in a catalytic cracking raw material, dust generated by a catalyst itself, and the like. The sulfur, nitrogen and other compounds in the VOCs can also form SOx, NOx and other harmful gases in the combustion process, so that the requirements can be met by directly utilizing the original purification device for treating FCC regenerated flue gas and correspondingly and properly adjusting the process parameters without adding additional flue gas post-treatment process and equipment, and the emission standard is met.

Preferably, the purification treatment method comprises the following steps:

contacting the flue gas with desulfurization circulating liquid in a quenching desulfurization tower, cooling, dedusting and desulfurizing, wherein the SOx concentration of the desulfurized flue gas is not more than 150mg/m³；

The desulfurized flue gas enters the bottom of the denitration tower after passing through the dust and mist removal device and reversely contacts with the denitration liquid, and the purified flue gas is emptied after passing through the mechanical mist removal device, so that the aim of ultralow emission is fulfilled.

The purification treatment method realizes ultralow emission of the flue gas with lower cost.

Compared with the prior art, the method not only combines various different purification processes, but also comprehensively considers the desulfurization and denitrification cost, the SOx removal rate, the NOx removal rate and the like, cools, removes dust and desulfurizes the flue gas through alkaline cleaning, and the maximum concentration of SOx in the desulfurized flue gas is not more than 150mg/m³The consumption of follow-up denitration liquid is reduced as far as possible, the cost of desulfurization and denitration is reduced, and through droplet and particulate matter in the further desorption flue gas of dust removal defroster, both purified the flue gas, reduced again because the flue gas smugglies the volume of the desulfurization liquid that gets into the denitration tower secretly, reduced the consumption of follow-up denitration liquid, reduced the denitration cost. Finally, chlorite is used as an oxidant for deep desulfurization and denitration, the improved chlorite-hypochlorite compound solution is preferably selected, the concentration of sulfur oxides in the purified flue gas is basically zero, and the concentration of NOx is 30mg/m³The aim of ultra-low emission is achieved。

Preferably, the circulating desulfurization solution is sodium lye, and the pH value of the circulating desulfurization solution is 5-9, such as 6, 7, 8 and 9.

Preferably, the denitration liquid is an alkaline solution containing chlorite, and has a pH value of 7-13 and a mass percent concentration of 0.1-10 wt%, preferably 0.1-5 wt%, such as 0.2 wt%, 0.5 wt%, 1 wt%, 2 wt%, 5 wt%, 7 wt%, 9 wt%.

When the concentration of the chlorite is higher, the desulfurization and denitrification efficiency is high, but the corresponding cost is increased, the utilization rate is reduced, the industrial application is not suitable, the chlorite with the mass percentage concentration of 0.1-10 wt% and the auxiliary agent are selected to be combined, the purification effect is better, the cost performance is higher, and the mass percentage concentration of 0.1-5 wt% is more preferable.

Preferably, the denitration liquid also contains hypochlorite, the hypochlorite has weaker oxidizability than chlorite, but has stronger oxidizability than single chlorite after being compounded with chlorite, and the hypochlorite cost is low, so that the cost can be reduced while high removal rate is ensured by adopting the compound liquid of the hypochlorite and the chlorite, and the preferable mass percentage concentration is 0.1-10 wt%, preferably 0.1-5 wt%, for example, 0.5 wt%, wt%, 0.7 wt%, 0.8 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%.

Preferably, the molar ratio of hypochlorite to chlorite in the denitration liquid is 0.01-15: 1, preferably 0.01-8: 1.

Preferably, the reaction time in the denitration is 0.1 to 5 seconds, preferably 0.5 to 2 seconds.

In summary, compared with the prior art, the invention achieves the following technical effects:

(1) the cost is greatly reduced, and the burden of enterprises is really reduced.

(2) The pollution problem caused by combustion of VOCs is solved.

(3) And the method is compatible with the existing equipment and is easier to popularize.

(4) Can realize the ultra-clean emission of flue gas: the SOx in the purified flue gas basically realizes zero emission, and the content of the NOx is controlled to be 30mg/Nm³The following.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following detailed description, but those skilled in the art will understand that the following described examples are some, not all, of the examples of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Example 1

On an FCC pilot plant, the regenerator temperature was 690 ℃ and the main air volume was 1.0m³The concentration of VOCs (relative to main wind) is 5160mg/m under the condition that catalytic gasoline is used as the feed of the simulated VOCs³When the catalyst is used, the removal rate reaches 100 percent.

Example 2

On an FCC pilot plant, the regenerator temperature was 690 ℃ and the main air volume was 1.0m³The concentration of VOCs is 12900mg/m under the condition of taking catalytic gasoline as the feed of the simulated VOCs³And the removal rate reaches 99.5 percent. Example 3

On an FCC pilot plant, the regenerator temperature was 690 ℃ and the main air volume was 1.0m³H, under the condition of taking catalytic gasoline as the feed for simulating VOCs, the concentration of the VOCs is 20000mg/m³When the amount was increased, the removal rate was 97.8%.

Example 4

On an FCC pilot plant, the regenerator temperature was 690 ℃ and the main air volume was 1.0m³Under the condition of/h, when straight-run kerosene is taken as a simulated feed, the concentration of VOCs is 10000mg/m³In this case, the removal rate was 99.8%.

Example 5

On an FCC pilot plant, the regenerator temperature was 690 ℃ and the main air volume was 1.0m³Under the condition of/h, when straight-run kerosene is taken as a simulated feed, the concentration of VOCs is 20000mg/m³When the removal rate is 97.6 percent, the removal rate reachesGood results.

Example 6

The flue gas produced in example 5 was subjected to the following purification treatment:

and (3) desulfurization:

flue gas from a waste heat boiler of an FCC regenerator device is fully contacted with circulating liquid in a quenching washing tower, and the pH value of the circulating liquid is controlled to be 5-9 by adding fresh sodium alkali liquid. The quenching washing tower is an empty tower. The concentration of sulfur dioxide in the purified flue gas is 30mg/m³The desulfurization rate was 83.3%.

Denitration:

flue gas from the desulfurizing tower gets into the reverse abundant contact of denitration bottom of denitration liquid, and the denitration tower is the packed tower. Sodium chlorite solution is used as absorbent, and the mass fraction of the sodium chlorite solution is 4 percent. The absorption temperature is 50 ℃, the retention time is 1s, and the liquid-gas ratio is 0.5L/m³. After the countercurrent contact, the SOx and the NOx are fully oxidized and absorbed, the concentration of sulfur dioxide in the flue gas is basically zero, and the concentration of the NOx in the flue gas is reduced to 30mg/m³。

Example 7

The difference from example 6 is the different conditions of the purification treatment:

desulfurization of

And (3) fully contacting the high-temperature flue gas discharged from the waste heat boiler of the FCC regenerator with circulating liquid in a quenching washing tower, and controlling the pH value of the circulating liquid to be 5-9 by adding fresh sodium alkali liquor. The quenching washing tower is an empty tower. The sulfur dioxide concentration of the purified flue gas is 29.5mg/m³The desulfurization rate was 88%.

Denitration

Flue gas from the desulfurizing tower gets into the reverse abundant contact of denitration bottom of denitration liquid, and the denitration tower is the packed tower. Sodium chlorite solution is used as absorbent, and the mass fraction of the sodium chlorite solution is 1.5 percent. The absorption temperature is 50 ℃, the retention time is 1s, and the liquid-gas ratio is 0.4L/m³. After the countercurrent contact, the SOx and the NOx are fully oxidized and absorbed, the concentration of sulfur dioxide in the flue gas is basically zero, and the concentration of the NOx in the flue gas is reduced to 15mg/m³。

Example 8

desulfurization of

Flue gas from a waste heat boiler of an FCC regenerator device is fully contacted with circulating liquid in a quenching washing tower, and the pH value of circulating slurry is controlled to be 5-9 by adding fresh sodium alkali liquor. The quenching washing tower is an empty tower. The sulfur dioxide concentration of the purified flue gas is 42mg/m³The desulfurization rate was 85.5%.

Denitration

Flue gas from the desulfurizing tower gets into the reverse abundant contact of denitration bottom of denitration liquid, and the denitration tower is the packed tower. At a temperature of 50 ℃ and a liquid-gas ratio of 0.3L/m³And denitrating liquid NaClO₂When the mass concentration is 2.5 percent and the retention time is 1.1S, the SOx and the NOx are fully oxidized and absorbed, the concentration of sulfur dioxide in the denitrated flue gas is basically zero, and the concentration of NOx is 25mg/m³。

Example 9

The difference from example 8 is that NaClO is used for denitration₂The mass percentage concentration is 6%.

The concentration of sulfur dioxide in the denitrated flue gas is basically zero, and the concentration of NOx is 5mg/m³The following.

In summary, all the results of the examples show that: the invention can realize that the FCC regenerator is used for simultaneously carrying out VOCs combustion treatment and catalyst regeneration, quickly and efficiently remove VOCs in refining enterprises at low cost, and can also realize ultralow emission of flue gas.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. a processing method of volatile organic matter in refinery is characterized in that, volatile organic matter is passed into catalytic cracking regenerator, combustion reaction occurs under the combustion-supporting of coke on regenerated catalyst, and the temperature of described combustion reaction is 650-750℃, the concentration of volatile organic compounds before entering the regenerator is ≤30000mg/m ³ ;

The volatile organic compounds and the regenerated catalyst undergo combustion reactions simultaneously in the same catalytic cracking regenerator, and the combustion of the volatile organic compounds and the regeneration of the catalyst are respectively completed.

2 . The method for treating volatile organic compounds in a refinery according to claim 1 , wherein the concentration of the volatile organic compounds entering the regenerator is ≤ 25000 mg/m ³ . 3 .

3 . The method for treating volatile organic compounds in a refinery according to claim 2 , wherein the concentration of the volatile organic compounds entering the regenerator is ≤ 20000 mg/m ³ . 4 .

4 . The method for treating volatile organic compounds in a refinery according to claim 3 , wherein the concentration of the volatile organic compounds entering the regenerator is ≤16000 mg/m ³ .

5 . The method for treating volatile organic compounds in a refinery according to claim 1 , wherein the temperature of the combustion reaction is 690-710° C. 6 .

6. The method for treating volatile organic compounds in a refinery according to any one of claims 1-5, characterized in that, when the volatile organic compounds undergo a combustion reaction, the volatile organic compounds and the The regenerated catalyst undergoes a combustion reaction at the same time; the flue gas after VOCS combustion enters the flue gas treatment system together with the flue gas generated by the regeneration of the regenerated catalyst.

7. The processing method of volatile organic compounds in refinery according to claim 6, is characterized in that, the method for described flue gas processing is:

The flue gas is contacted with the desulfurization circulating liquid in the quenching desulfurization tower to conduct cooling, dust removal, and desulfurization, and the SOx concentration of the flue gas after desulfurization is not more than 150 mg/m ³ ;

The desulfurized flue gas enters the bottom of the denitrification tower after passing through the dust removal and mist eliminator, and is in reverse contact with the denitrification liquid, and the purified flue gas is evacuated through the mechanical demisting device.

8 . The method for treating volatile organic compounds in a refinery according to claim 7 , wherein the circulating liquid is sodium lye with a pH value of 5-9. 9 .

9 . The method for treating volatile organic compounds in a refinery according to claim 7 , wherein the denitrification solution is an alkaline solution containing chlorite, and its pH value is 7 to 13, and the mass percentage concentration is 9 . 0.1～10wt%.

10 . The method for treating volatile organic compounds in a refinery according to claim 9 , wherein the mass percentage concentration of chlorite in the denitration solution is 0.1-5 wt %. 11 .

11 . The method for treating volatile organic compounds in a refinery according to claim 9 , wherein the denitration solution further contains hypochlorite, and the mass percentage concentration is 0.1-10 wt %. 12 .

12 . The method for treating volatile organic compounds in a refinery according to claim 11 , wherein the mass percentage concentration of hypochlorite in the denitration solution is 0.1-5 wt %. 13 .