CN203075827U - A low-resistance, water-saving catalytic cracking flue gas absorption tower - Google Patents

Abstract

The utility model provides a low resistance, water-saving catalytic cracking flue gas absorption tower, which comprises a tower body, a washing absorption section and a flue gas outlet which are arranged at the upper part of the tower body, and an absorption liquid circulating groove which is arranged at the lower part of the tower body; wherein the absorption section is downwards sequentially composed of a gas-liquid separator, a fresh water spray head, an alkali liquor spray head, an absorption liquid spray head, a Venturi grid and a flue gas inlet quenching spray head; the lower part of the absorption liquid circulating tank is provided with an aeration nozzle, and the bottom of the absorption liquid circulating tank is provided with an absorption liquid outlet. The utility model discloses absorption tower festival water, purification efficiency height, resistance are low, are fit for current catalytic cracking gas cleaning's industrialization and use.

Description

A low-resistance, water-saving catalytic cracking flue gas absorption tower

technical field

The utility model belongs to the field of catalytic cracking flue gas desulfurization equipment, in particular to a catalytic cracking flue gas desulfurization and dust removal absorption tower. the

Background technique

Catalytic cracking (FCC) regenerator flue gas contains a large amount of SOx, particulate matter, etc., and has become an important source of air pollution. It is estimated that the SO _X emitted by refineries accounts for 6% to 7% of its total emissions, while the SO _X emitted by catalytic cracking accounts for about 5%. In recent years, as the proportion of processed high-sulfur crude oil continues to increase, the concentration of SO _x emissions has a tendency to increase; at the same time, with the development of catalytic cracking and refining industry, the dust pollution caused by catalyst fine powder carried by flue gas to the environment is also increasing. aggravated. In November 2010, the Ministry of Environmental Protection of the People's Republic of China began to widely solicit opinions on the proposed "Petroleum Refining Industry Pollutant Discharge Standards". The standard stipulates that starting from July 1, 2014, the sulfur dioxide and particulate matter in the regeneration flue gas of the catalytic cracking unit of existing enterprises shall not exceed 400mg/m ³ and 50mg/m ³ respectively.

At present, domestic flue gas desulfurization and dust removal are mainly concentrated in the flue gas treatment of coal-fired boilers. There are few studies on desulfurization and dust removal of catalytic cracking flue gas, and there is no mature industrial technology. The composition and treatment process are different, so that the desulfurization and dust removal equipment developed for coal-fired boilers cannot be directly applied to the treatment of catalytic cracking regeneration flue gas. the

The flue gas desulfurization and dust removal technologies of catalytic cracking units currently imported in China are all from the United States. The core equipment of this technology is an empty tower spray absorption tower, which consists of a short spray section, a filter assembly and a droplet separator. All equipment The components are all installed and integrated in an upflow tower. The flue gas from catalytic cracking enters the spray tower and is immediately cooled to the saturation temperature. The spray tower is an empty tower. When the upstream system fails and a large amount of catalyst is brought in, there will be no clogging problem. There are multiple layers in the tower Injection nozzle and quenching nozzle (LAB-G nozzle), the uniquely designed nozzle is the key of the system, which has the characteristics of non-clogging, wear resistance, corrosion resistance, and can handle high-concentration slurry. The flue gas entering the spray tower is immediately quenched to the saturation temperature, and then contacted with spray droplets containing absorbent solution to wash the catalyst particles and absorb SOx. The nozzles emit relatively large droplets to prevent mist formation, eliminating the need for clogged conventional demisters. After the saturated gas leaves the spray tower, it directly enters the EDV filter assembly to remove fine particles, and removes fine particles through saturation, condensation and filtration. After the gas in the saturated state is slightly accelerated, it reaches a supersaturated state through adiabatic expansion, and the fine particles and acid mist will condense and accumulate, and the particle size will increase sharply, greatly reducing the energy and complexity required to remove these two types of substances. The bottom of the filter assembly is equipped with an upward-spraying LAB-F nozzle to collect fine particles and acid mist. Its advantage is that it removes fine particles under extremely low pressure drop and is not sensitive to changes in gas flow. In order to ensure that the flue gas enters the chimney without liquid droplets, a droplet separator is installed to further remove the fine liquid in the flue gas. The separator is a hollow structure with a spiral guide piece inside, which guides the gas to flow in a spiral shape. When flowing downward, it is thrown to the wall of the vessel under the action of centrifugal force, thereby separating from the gas. The main problems in the operation of the absorption tower are the large resistance of the absorption tower and the large amount of fresh water replenishment. the

Utility model content

The purpose of the utility model is to overcome the deficiencies of the prior art and provide a high-efficiency, water-saving catalytic cracking regeneration flue gas desulfurization and dust removal absorption tower under the condition of improving the effects of flue gas desulfurization and dust removal. the

The utility model catalytic cracking flue gas desulfurization, dust removal absorption tower is composed of a tower body 1, a washing absorption section 2 placed on the upper part of the tower body 1, a flue gas outlet 16, and an absorption liquid circulation tank 3 placed at the lower part of the tower body 1; The absorption section 2 is composed of gas-liquid separator 4, fresh water nozzle 9, lye nozzle 10, absorption liquid nozzle 11, Venturi grid 12 and flue gas inlet quenching nozzle 13; the lower part of the absorption liquid circulation tank is equipped with The air spray head 14 is provided with an absorption liquid outlet 15 at the bottom. the

When the flue gas with liquid droplets enters the channel of the corrugated plate 5 of the gas-liquid separator 4, the flue gas continuously deflects in the flow channel of the demister, and the liquid droplets carried in the wet flue gas collide with each other under the action of inertial force. The surface of the demister is adhered to the wall surface of the plate to form a thin liquid film, and liquid droplets are formed at the lower end of the plate to fall to the collection tank 6 of the gas-liquid separator 4 to achieve the purpose of demisting. In order to ensure the resistance of the gas-liquid separator 4 during operation, a demister resistance monitor 7 is installed to monitor the resistance of the gas-liquid separator. When the resistance of the resistance monitor 7 is greater than 150 Pa, the gas-liquid separator is opened to clean the nozzle 8 , to clean the flap demister. the

The working principle of the absorption tower of the utility model is as follows: the hot flue gas first enters the flue gas absorption tower, and when entering the flue gas absorption tower, it is cooled to below 80°C by the fresh water of the quenching nozzle, and the cooled flue gas enters the venturi grid layer. The circulating absorption liquid sprayed with the tarpaulin, the lye with a mass concentration of 18%, and fresh water remove the sulfide and large catalyst particles in the flue gas, and the flue gas is evenly distributed; after the flue gas is washed by the Venturi grid , through the circulating absorption liquid between the Venturi grille and the absorption liquid nozzle, lye with a mass concentration of 18%, and fresh water for further washing and absorption, and the flue gas is further adiabatically evaporated and cooled during this process; after the second washing and absorption The flue gas continues to rise, and is further washed and absorbed by the 18% lye and fresh water between the absorption liquid nozzle and the 18% lye nozzle; the flue gas after three times of washing is further absorbed by the fresh water during the rising process, and is cooled by adiabatic evaporation at the same time. The gas temperature is less than 40°C; the flue gas that continues to rise passes through the gas-liquid separator to separate water, and then is discharged into the atmosphere through the flue gas outlet 16. When the resistance of the gas-liquid separator is greater than 150Pa, the gas-liquid separator is opened to clean the nozzle, and the gas-liquid The separator is cleaned. the

Compared with the prior art, the utility model patent has the biggest advantage of:

1. Low resistance, system resistance is less than 1500Pa, suitable for industrial application of existing catalytic cracking flue gas purification, no need to modify the existing catalytic cracking process. the

2. Water saving, absorbing liquid, lye, and fresh water are sprayed in sequence, and the high-efficiency gas-liquid separation device at the top of the absorption tower reduces the water discharged into the atmosphere through the flue gas. the

3. The purification efficiency is high, and the step-by-step wet washing is adopted, especially the deep washing of the flue gas by lye, which improves the desulfurization effect. the

Description of drawings

Fig. 1 is the structural representation of the utility model absorption tower;

Fig. 2 is the plane arrangement diagram of the alkali solution nozzle and the absorption liquid nozzle in the absorption tower;

Fig. 3 is the plane arrangement diagram of the fresh water nozzle in the absorption tower;

Fig. 4 is the schematic diagram of gas-liquid separator in the absorption tower;

1-absorption tower, 2-absorption section of absorption tower, 3-absorption liquid circulation tank, 4-gas-liquid separator, 5-wave plate of gas-liquid separator, 6-droplet collection tank of gas-liquid separator, 7-gas-liquid Separator resistance monitor, 8- gas-liquid separator cleaning nozzle, 9- fresh water nozzle, 10- lye nozzle, 11- absorption liquid nozzle, 12- Venturi grille, 13- flue gas inlet quenching nozzle, 14- The aeration nozzle at the bottom of the absorption liquid circulation tank, 15-absorption liquid outlet, 16-flue gas outlet. the

Detailed ways

Below in conjunction with accompanying drawing, the absorption tower of the present invention and its working process are described in further detail. the

Shown in Fig. 1 is the absorption tower of the present utility model, is made up of tower body 1, is placed in the washing absorbing section 2 of tower body 1 top and flue gas outlet 16, is placed in the absorption liquid circulation groove 3 of tower body 1 bottom; Wherein absorption section 2. The gas-liquid separator 4 is arranged downward in turn, and the gas-liquid separator is provided with a gas-liquid separator resistance monitor 7 and a gas-liquid separator cleaning nozzle 8, a fresh water nozzle 9, 18% lye nozzle 10, and an absorption liquid nozzle 11 , composed of Venturi grille 12 and flue gas inlet quenching nozzle 13; the lower part of the absorption liquid circulation tank is provided with an aeration nozzle 14, and the bottom is provided with an absorption liquid outlet 15. the

The flue gas enters the flue gas inlet at the lower part of the absorption tower through the flue, and after being cooled by the fresh water sprayed by the quenching nozzle 13, it passes through the Venturi grille 12, and the airflow velocity of the flue gas is adjusted on the Venturi grille 12, so that It is evenly distributed, and is washed and absorbed once; after the first washing and absorption, the circulating absorption liquid, 18% lye, and fresh water between the Venturi grid 12 and the absorption liquid nozzle 11 are used for secondary washing and absorption; after the second washing The absorbed flue gas continues to rise, and the 18% lye and fresh water between the absorbed liquid nozzle 11 and the 18% lye nozzle 10 are washed and absorbed three times; the flue gas after three washings continues to rise, and is sprayed by the fresh water nozzle 9 The fresh water is further washed and absorbed, and the temperature of the flue gas is less than 40°C; the flue gas that has been washed and absorbed four times passes through the gas-liquid separator 4 to separate the water, and is discharged into the atmosphere through the flue gas outlet 16. When the resistance monitor of the gas-liquid separator When the resistance of 7 is greater than 150Pa, open the gas-liquid separator to clean the nozzle 8 to clean the gas-liquid separator. The circulating absorption liquid, 18% lye, and fresh water flow into the absorption liquid circulation tank 3 at the lower part of the absorption tower 1. In the absorption liquid circulation tank, the absorption liquid is agitated by the air ejected from the aeration nozzle 14, on the one hand to prevent catalyst particles from settling The pipeline is blocked at the bottom of the absorption liquid circulation tank 3, and the sulfite in the circulation absorption liquid can also be oxidized to sulfate by air at high temperature to reduce the COD and temperature of the circulation absorption liquid, and the evenly stirred absorption liquid passes through the absorption liquid tank The absorption liquid outlet 15 at the bottom is discharged. the

Fig. 2 is the plane layout of the alkali solution nozzle and the absorption liquid nozzle in the absorption tower; Fig. 3 is the plane layout of the fresh water nozzle in the absorption tower; the nozzles in the absorption tower are distributed in three layers, and each layer sprays different liquids, The bottom layer is the absorption liquid nozzle 11. The absorption liquid nozzle 11 sprays the absorption liquid from the absorption liquid circulation tank 3 at the lower part of the absorption tower 1. Three absorption liquid nozzles are arranged on the same horizontal plane, forming an angle of 120 degrees with each other to ensure the spraying The absorbing liquid is as uniform as possible on the same horizontal plane; the middle is the lye nozzle 10, and the spray mass concentration is 18% lye. 60 degree included angle; fresh water nozzle 9 on the top layer, fresh water nozzle 9 sprays fresh water, 6 fresh water nozzles are set on the same horizontal plane, 60 degree included angle with each other, and lye nozzle 10, absorption liquid nozzle 11 They form an angle of 30 degrees with each other. This nozzle distribution method can make the liquid evenly distributed on the same horizontal plane to prevent gas short circuit. The fresh water nozzle 9 is placed on the uppermost layer, and it can also flush the lye on the wall of the absorption tower to prevent absorption. Scaling and corrosion of tower walls. the

Fig. 4 is the schematic diagram of gas-liquid separator 4 in the absorption tower, and this gas-liquid separator is a corrugated plate separator, and gas-liquid separator 4 is made up of gas-liquid separator corrugated plate 5 and gas-liquid separator drop collection tank 6, and in The gas-liquid separator 4 is equipped with a resistance monitor 7 and a cleaning nozzle 8 of the gas-liquid separator. When the absorption section is not operating normally or the system fails and a large amount of catalyst is brought in to block the gas-liquid separator, the resistance of the resistance monitor 7 can be passed. When it is greater than 150Pa, the gas-liquid separator cleaning nozzle 8 cleans the gas-liquid separation device 4 to ensure long-term stable operation of the absorption tower. the

Claims (8)

1. A catalytic cracking flue gas absorption tower is characterized in that by the tower body (1), the washing absorption section (2) placed on the upper part of the tower body (1) and the flue gas outlet (16) and placed on the tower body (1) ) is composed of the absorption liquid circulation tank (3) at the lower part; the absorption section (2) consists of gas-liquid separator (4), fresh water nozzle (9), lye nozzle (10) and absorption liquid nozzle (11) downwards in turn , Venturi grille (12) and flue gas inlet quenching nozzle (13). the 2. The absorption tower according to claim 1, characterized in that the lower part of the absorption liquid circulation tank is provided with an aeration nozzle (14). the 3. The absorption tower according to claim 1, characterized in that an absorption liquid outlet (15) is provided at the bottom of the absorption liquid circulation tank. the 4. The absorption tower according to claim 1, characterized in that the absorption liquid nozzle (11) sprays the absorption liquid from the absorption liquid circulation tank (3) at the lower part of the absorption tower (1), and the absorption liquid nozzle is set on the same horizontal plane Three, each forming an angle of 120 degrees. the 5. The absorption tower as claimed in claim 1, characterized in that what is sprayed by the lye nozzle (10) is lye with a mass concentration of 18%, and three lye nozzles are arranged on the same horizontal plane, forming an angle of 120 degrees with each other , forming an angle of 60 degrees with the nozzle of the absorption liquid. the 6. The absorption tower as claimed in claim 1, characterized in that 6 fresh water nozzles (9) on the uppermost layer are arranged on the same horizontal plane, forming an included angle of 60 degrees with each other, and forming a 30-degree angle with the lye nozzle and the absorption liquid nozzle. horn. the 7. The absorption tower according to claim 1, characterized in that the gas-liquid separator (4) is a corrugated plate. the 8. The absorption tower according to claim 1, characterized in that the upper part of the gas-liquid separator is provided with a resistance monitor (7) and a cleaning nozzle (8) of the gas-liquid separator. the

Images