CN102705704A - Fume circulating system for fume impact water-spinning type LNG heating and gasifying furnace - Google Patents

Abstract

The invention relates to an improved device for a flue gas impingement water cyclone type LNG heating gasifier, and a flue gas circulation system of the flue gas impingement water cyclone type LNG heating gasifier. The fan (16) is set, and the smoke exhaust pipe (15) is set on the annular cover plate at the top of the vertical outer cylinder. Exhaust pipe (19), exhaust air damper (18) is set in exhaust pipe (19); Between fan (16) air outlet and exhaust air damper (18), circulating flue (17) is set Lead to the annular top of the combustion chamber (7), set the circulation flue damper (20) in the circulation flue (17); said smoke exhaust pipe (15) and circulation flue (17) pass through at least two above respectively The interfaces are uniformly distributed in the circumferential direction and are respectively connected to the top annular cover plate of the casing (8) and the annular top of the combustion chamber (7). By adopting the invention, the circulating flue gas flow rate can be adjusted to ensure the normal operation of the LNG heating gasification furnace, and the operating efficiency can be increased by about 2%. The economic value and social benefit are extremely considerable.

Description

A flue gas circulation system of a flue gas impingement hydrocyclone type LNG heating gasifier

technical field

The invention relates to an improved device for a flue gas impingement water cyclone type LNG heating gasifier, in particular to an improved device for the flue gas circulation system of the flue gas impingement water cyclone type LNG heating gasifier.

technical background

Natural gas is a clean energy with high calorific value, low pollution of combustion products, and convenient storage and transportation. At a time when energy conservation and emission reduction have become a global consensus, natural gas has become one of the directions of energy development. In terms of transportation, natural gas is often transported by pipeline, such as China's West-East Gas Pipeline, or condensed and liquefied natural gas into liquefied natural gas (LNG for short), which greatly reduces its volume (under normal pressure, 625M ³ natural gas can condensed into 1 M ³ LNG), and then transported by ships, vehicles and other vehicles. For example, China uses large LNG carriers to ship imported LNG from abroad; in terms of storage, natural gas is generally stored in underground gas storage, pipeline gas storage or large spherical tanks. Gas, and LNG has more advantages, it only needs a smaller liquid storage container to store a large amount of natural gas. However, when in use, LNG still needs to be heated and gasified into natural gas at the pressure and temperature required by the process before it can be used in the project. Therefore, in the LNG gas supply system, there must be a device for heating and gasifying LNG, which is an indispensable essential equipment.

The inventor proposed and obtained the patent No. ZL201010113494.6 in 2010, which is a novel LNG heating gasification device. The gasification furnace uses combustion to generate The high-speed flue gas impacts the airflow swirling water submerged in the pool, splashes and entrains water droplets, water mist, and water vapor to form a flue gas flow with high humidity, and heats and vaporizes the LNG flowing in the coil through the coil. In order to achieve the natural gas supply parameters required by the process. The reason why the high-temperature flue gas hits the water surface to form a wet air flow is to reduce the temperature of the flue gas entering the coil, so that the temperature of the flue gas directly contacting the coil is lower than the ignition temperature of LNG, so as to ensure the safety of the LNG heating gasifier The second is to transfer part of the heat carried by the flue gas to the water in the pool to increase the water temperature to heat the natural gas flowing in the coil pipe immersed in the pool.

The specific structure of the flue gas impingement hydrocyclone type LNG heating gasification device is as follows:

A combustion chamber is installed on the top of a vertical airtight cylindrical shell, the combustion chamber is composed of an inner cylinder and an outer cylinder, a burner is installed on the top of the inner cylinder, and a conical flue gas nozzle is installed at the lower end of the outer cylinder; A heat exchange surface arrangement space is formed between the inner walls of the cylindrical shell, and a smoke exhaust pipe is provided on the upper part of the heat exchange surface arrangement space;

A jacket structure combustion chamber is formed between the combustion outer cylinder and the inner cylinder, the bottom of the combustion chamber communicates with the conical nozzle, and the top of the combustion chamber communicates with the smoke exhaust pipe through the circulating flue;

Set the smoke exhaust duct damper in the smoke exhaust duct, and the circulating flue damper in the circulating flue;

The lower part of the vertical airtight cylindrical shell is a pool for accumulating water. The water surface of the pool is partly submerged in an inverted umbrella-shaped airflow vortex. It is a curved surface that first descends to the edge of the disc and then slightly upwards in a certain curved shape;

In the arrangement space of the heat exchange surface, coils are arranged in a spiral arrangement around the combustion chamber; one end of the coil is the LNG inlet, and the other end is the natural gas outlet.

The gasification furnace uses the flue gas produced by fuel combustion to impact the air flow water submerged in the pool at high speed, splashing and entraining water droplets, water mist, and water vapor to form a flue gas flow with high humidity, which flows through the coil to heat the gas The LNG flowing in the coil is vaporized to make the LNG gasify and meet the natural gas supply parameters required by the process. The reason why the high-temperature flue gas hits the water surface to form a wet air flow is to reduce the temperature of the flue gas entering the coil, so that the temperature of the flue gas directly contacting the coil is lower than the ignition temperature of LNG, so as to ensure the safety of the LNG heating gasifier run. The second is that the condensation heat transfer when the water vapor in the flue gas condenses is beneficial to improve the heat transfer efficiency between the flue gas and the coil. The third is to transfer part of the heat carried by the flue gas to the water in the pool, so as to increase the water temperature and heat the natural gas flowing through the coil pipe immersed in the pool. Therefore, effectively splashing the flue gas and entraining water droplets, water mist, and water vapor is the key technology for this type of heating gasifier.

The main factor for the flue gas to effectively splash and entrain water droplets, water mist, and water vapor depends on the flue gas velocity, and the flue gas velocity depends on the flue gas flow rate and its flow cross section. When the rated amount of LNG that needs to be heated and vaporized is determined, The amount of fuel required and the amount of flue gas produced have also been determined. In this way, when the cross-sectional area of flue gas flow, that is, the area of the nozzle, is determined, it is an effective method to increase the amount of flue gas by using flue gas circulation. To ensure the required amount of flue gas, and to ensure a higher temperature of the gas entering the furnace, which is conducive to the operation of the furnace, therefore, the flue gas circulation device is a very important and sensitive working part.

The structure of the flue gas circulation device in the prior art is as mentioned above. The top of the combustion chamber communicates with the lower casing through the circulation flue, and the side of the circulation flue is connected to the exhaust pipe, which is discharged to the atmosphere through the fan. Set the damper of the circulating flue, and set the damper of the exhaust duct in the exhaust duct.

Practice has proved that such a structure is not good. Installing the fan and configuring the pipeline and damper in this way, no matter whether the fan is working or not, no matter whether the suction force of the fan is large or small, no matter how the damper of the circulating flue or the damper of the exhaust pipe is opened Closed, it has little effect and influence on the flue gas in the circulating flue. It is difficult to adjust the amount of recirculated flue gas in the entire flue gas circulation system, which greatly affects the operation effect of the heating gasification device, and sometimes even fails to operate. It needs to be improved and solved urgently. .

Contents of the invention

The present invention intends to provide a flue gas circulation system of the flue gas impingement hydrocyclone type LNG heating gasifier, in order to improve and increase the flue gas circulation efficiency of the heating gasifier, maintain the normal operation of the heating gasifier, and improve the operation effect Purpose.

The purpose of the present invention is achieved by the following structure:

A flue gas circulation system of a flue gas impingement hydrocyclone type LNG heating gasifier. A combustion inner cylinder is installed in the center of the top of the vertical cylindrical shell. The combustion chamber is composed of an inner cylinder and an outer cylinder. The top of the inner cylinder is installed with a combustion The lower end of the outer cylinder is a conical flue gas nozzle, and the lower part of the shell is provided with an air flow swirl; it is characterized in that:

A fan is installed, the air inlet of the fan is connected to the top annular cover plate of the shell of the heating gasification furnace through the exhaust pipe, the air outlet of the fan is connected to the exhaust pipe exhausted to the atmosphere, and the exhaust damper is arranged in the exhaust pipe;

The smoke exhaust pipe is connected to the top annular cover plate of the shell through at least two or more interfaces, which are evenly distributed in the circumferential direction;

Between the air outlet of the fan and the exhaust damper, set the circulating flue to connect to the annular top of the combustion chamber, and set the circulating flue damper in the circulating flue;

The circulating flue is connected to the annular top of the combustion chamber through at least two or more interfaces, which are uniformly distributed in the circumferential direction;

The cone angle of the flue gas nozzle is 8-20 degrees.

By adopting this technical scheme, through the setting and configuration of the fan and its pipes and damper, through the adjustment of the speed of the fan, through the opening and closing of the exhaust damper and the circulating flue damper and the opening degree, it can be adjusted according to the size of the smoke. The working load of the gas impingement cyclone type LNG heating gasifier and the size of the firepower of the burner are controlled and adjusted to achieve the most suitable match and high work efficiency.

For example, close the exhaust damper and open the circulating flue damper, the fan should be able to provide strong circulating flue gas to the combustion chamber, and properly adjust the opening of these two doors, it should be able to gasify the LNG with the amount of heating and According to the temperature condition, the circulating flue gas flow rate is adjusted according to the process needs to achieve a more suitable and economical working state, improve the working efficiency of the gasifier, and save energy.

The technical feature that the circulating flue is connected to the annular top of the combustion chamber through at least two interfaces uniformly distributed in the circumferential direction changes the uneven flow and poor effect caused by the circulating flue gas entering the combustion chamber from only one side in the prior art The defects and problems of the combustion chamber can be evenly distributed in the circumferential direction, so that the inner wall of the combustion chamber can be cooled evenly, and the flue gas in the conical nozzle can be mixed more evenly. The number of branch interfaces of the circulating flue is determined according to the specifications of the LNG heating gasifier, the diameter of the combustion chamber and the process requirements, in order to ensure the uniformity of the circulating flue gas flowing in the annular jacket of the combustion chamber.

In the same way, the technical feature that the smoke exhaust pipe is connected to the top annular cover plate of the shell through at least two interfaces uniformly distributed in the circumferential direction changes the prior art that the mixed smoke is only drawn from one side, resulting in the occurrence of The defects and problems of the dead angle of the flue gas flow, the effective heat exchange of the upper coil, and the decrease of the heat exchange efficiency of the entire device, the circumferential uniform configuration can improve the heat exchange efficiency of the entire device from another measure. As mentioned above, the number of branch joints of the exhaust pipe is also determined according to the specifications of the LNG heating gasifier, the diameter of the shell and the process requirements, in order to ensure that the extraction of the flue gas flows evenly in the shell.

A concentric cylinder called an outer cylinder is placed on the combustion chamber, and an annular jacket-type combustion chamber is formed between the outer cylinder and the inner cylinder; the length of the straight section of the outer cylinder is slightly longer than the length of the combustion chamber according to the process requirements; the diameter of the outer cylinder is based on The circulating flue gas flow rate is determined. One end of the outer cylinder is connected to the flue gas nozzle. The shape of the flue gas nozzle is a conical shrinking nozzle. The diameter of the nozzle is determined according to the required flue gas ejection speed. Mixing of high temperature flue gas from the combustion chamber with circulating flue gas from the annular jacket.

In this technical solution, the conical cone angle of the flue gas nozzle is 8-20 degrees, which plays an important role in ensuring the flue gas ejection speed and flue gas mixing effect, and ensuring that the entire heating furnace structure will not be too large. After calculation, experimentation and testing, the cone angle is too small and the flue gas nozzle is too long, resulting in the volume of the heating furnace being too long and too large, which makes the design of the heating furnace unreasonable, not only consumables, but also affects the overall work efficiency. On the contrary, the cone angle is too large , more than 20 degrees, the flue gas nozzle is too short, which not only leads to poor mixing of the flue gas in the nozzle, but also high-temperature flue gas generated by combustion directly impacts the wall of the nozzle and burns the nozzle.

Therefore, this technical solution improves and improves the existing technology from multiple angles, which not only eliminates and solves the shortcomings of the original design that cannot work normally, but also can effectively control the circulating flue gas flow rate according to the working conditions of the heating furnace, so that the heating Furnace efficiency has been significantly improved.

Further, the smoke exhaust pipe is connected to the top annular plate of the casing through three through holes uniformly distributed in the circumferential direction and spaced 120 degrees apart.

Further, the circulating flue is connected to the annular top of the combustion chamber through three through holes uniformly distributed in the circumferential direction and spaced 120 degrees apart.

Further, the cone angle of the flue gas nozzle is 16 degrees.

The features and advantages of the patent of the present invention are:

1. Overcome the deficiencies and defects of the flue gas circulation system in the existing technology patent No. ZL201010113494.6 "Flue gas impact water cyclone LNG heating gasifier", and provide a targeted flue gas circulation improvement device system , play the role of fans, pipelines and dampers, so that the circulation system can operate normally and achieve higher work efficiency.

2. Design a new flue gas circulation device system, so that the speed of the flue gas ejected from the conical nozzle can be adjusted and controlled to meet the process requirements, ensuring the effect of its impact splashing and entraining water droplets, water mist, and water vapor, ensuring Effective operation of flue gas impingement hydrocyclonic LNG heating gasifier.

3. When the low-temperature circulating flue gas is mixed with the high-temperature flue gas generated by combustion in the nozzle, the temperature of the mixed flue gas is effectively reduced to ensure that the flue gas temperature entering the coil meets the safety requirements.

4. When the low-temperature circulating flue gas flows through the annular jacket, the wall temperature of the combustion chamber is effectively cooled to ensure that the wall temperature of the combustion chamber does not exceed the temperature.

5. By adopting the flue gas circulation system of the present invention, the efficiency of the heating furnace can be improved by 2% compared with the original design. Now my country and the world are vigorously promoting LNG liquefied natural gas. The economic value and social benefit of the energy saving produced by the present invention are Extremely impressive.

The invention ensures the normal operation of the flue gas impinging water cyclone type LNG heating gasification furnace and improves the operation efficiency of the furnace.

Description of drawings

Fig. 1 is the configuration structure diagram of the flue gas impingement hydrocyclonic LNG heating gasifier and its flue gas circulation device in the prior art;

Fig. 2 is an embodiment of the flue gas circulation system of the flue gas impingement hydrocyclone type LNG heating gasifier of the present invention, and the general structural layout diagram arranged on the heating gasifier;

Fig. 3 is a structural configuration diagram of some components of the flue gas circulation in Fig. 2 .

In the picture:

1 is the annular pipe ring, 2 is the water pump, 3 is the water inlet pipe, 4 is the water tank, 5 is the bypass pipe, 6 is the regulating valve, 7 is the combustion chamber, 8 is the shell, 9 is the LNG coil, and 10 is the air flow water 11 is the flue gas nozzle, 12 is the connecting pipe, 13 is the inner cylinder, 14 is the burner interface, 15 is the smoke exhaust pipe, 16 is the fan, 17 is the circulating flue, 18 is the exhaust damper, 19 is the exhaust Trachea, 20 is a circulating flue damper.

Detailed ways

The structure of the present invention will be further described in detail below in conjunction with the accompanying drawings.

A flue gas circulation system of a flue gas impingement water-swirling LNG heating gasifier. An inner cylinder 13 of a combustion chamber is installed in the center of the top of a vertical cylindrical shell 8. The combustion chamber is composed of an inner cylinder 13 and an outer cylinder. The burner interface 14 is installed on the top of the cylinder 13, the lower end of the outer cylinder is a conical flue gas nozzle 11, and the lower part of the shell 8 is provided with an airflow swirl 10;

A fan 16 is provided, the air inlet of the fan 16 is connected to the top annular cover plate of the heating gasification furnace shell 8 by the smoke exhaust pipe 15, and the air outlet of the fan 16 is connected to the exhaust pipe 19 discharged to the atmosphere, and is arranged in the exhaust pipe 19 Exhaust damper 18;

The smoke exhaust pipe 15 is connected to the top annular cover plate of the shell 8 through at least two or more interfaces in the circumferential direction; this technical feature can adopt a pipe joint such as a "tee", which is divided into 15 points by a smoke exhaust pipe. The fork is two or more interfaces, which are evenly distributed in the circumferential direction and connected to the top annular cover plate of the casing 8, so that the smoke can be extracted from multiple places on the top of the casing 8 at the same time.

Between the air outlet of the blower fan 16 and the exhaust damper 18, the circulating flue 17 is set to be connected to the annular top of the combustion chamber 7, and the circulating flue damper 20 is set in the circulating flue 17;

The circulating flue 17 is connected to the annular top of the combustion chamber 7 through at least two or more interfaces, which are evenly distributed in the circumferential direction; with the same structure, this technical feature can adopt a pipe joint such as a "tee", and a circulating flue The channel 17 is bifurcated into two or more interfaces, which are evenly distributed in the circumferential direction and connected to the annular top of the combustion chamber 7, so that the circulating flue gas can be uniformly sent to multiple places of the combustion chamber 7 at the same time.

The cone angle of the smoke nozzle 11 is 8-20 degrees.

The smoke exhaust pipe 15 is connected to the top annular cover plate of the casing 8 through three through holes uniformly distributed in the circumferential direction and spaced 120 degrees apart. In general occasions, it is advisable to adopt three, which are simple in structure and can achieve better results.

The circulating flue 17 is connected to the annular top of the combustion chamber 7 through three through holes uniformly distributed in the circumferential direction with an interval of 120 degrees. Equally, it is advisable to adopt three in general occasion, both structure is simple, can reach better effect again.

The cone angle of the flue gas nozzle 11 is 16 degrees, and generally the cone angle of 16 degrees is better.

After comparing and testing a flue gas impingement water-swirling LNG heating gasifier with a total height of 2.5m and a shell 8 diameter of 1.3m, the conical cone angle of the flue gas nozzle 11 is 16 degrees. Under certain conditions, compared with the heating gasification furnace using the flue gas circulation device of the original technology, the efficiency of the gasification furnace is increased by 2%.

The invention ensures the normal operation of the flue gas impinging water cyclone type LNG heating gasification furnace, improves the operation efficiency of the furnace, can greatly save fuel and energy, has extremely considerable economic value and social benefits, and has great promotion and application prospects.

Both the prior art and the two comparative test schemes of the present invention have adopted the technical scheme of "A Device for Maintaining the Water Level of Flue Gas Impacting Water Cycling Type LNG Heating Gasifier" with the application number of 201210153604.0, and its structural features are as follows: On the top of the combustion chamber 7 composed of inner and outer cylinders, an annular pipe ring 1 is arranged horizontally, and a plurality of water replenishment holes are opened on the peripheral wall of the annular pipe ring 1; the annular pipe ring 1 is connected to the water tank 4 through the water inlet pipe 3, and the The water supply power pump 2 is configured on the road, so the positive effects on the two are the same, and the comparison accuracy between the two is not affected.

Claims (4)

1. A flue gas circulation system of a flue gas impingement water-swirling LNG heating gasifier, a combustion chamber (13) is installed in the center of the top of the vertical cylindrical shell (8), and the combustion chamber (7) consists of an inner cylinder (13) and an outer cylinder, the top of the inner cylinder (13) is equipped with a burner interface (14), the lower end of the outer cylinder is a conical flue gas nozzle (11), and the lower part of the shell (8) is provided with an airflow swirl ( 10); characterized in that: A fan (16) is provided, the air inlet of the fan (16) is connected to the top annular cover plate of the heating gasification furnace shell (8) by the exhaust pipe (15), and the air outlet of the fan (16) is connected to the exhaust gas discharged to the atmosphere. pipe (19), the exhaust damper (18) is set in the exhaust pipe (19); The smoke exhaust pipe (15) is connected to the top annular cover plate of the casing (8) through at least two or more interfaces, which are evenly distributed in the circumferential direction; Between the air outlet of the fan (16) and the exhaust damper (18), a circulating flue (17) is set to connect to the annular top of the combustion chamber (7), and a circulating flue is set in the circulating flue (17) Damper (20); The circulating flue (17) is connected to the annular top of the combustion chamber (7) through at least two or more interfaces, which are evenly distributed in the circumferential direction; The cone angle of the smoke nozzle (11) is 8-20 degrees. 2. According to the flue gas circulation system of the flue gas impingement hydrocyclone type LNG heating gasifier according to claim 1, it is characterized in that the flue gas exhaust pipe (15) is arranged through three circumferentially evenly distributed through holes at an interval of 120 degrees Attached to the top ring cover of the housing (8). 3. The flue gas circulation system of the flue gas impingement hydrocyclone type LNG heating gasifier according to claim 1, characterized in that the circulating flue (17) is arranged through three circumferentially evenly distributed through holes at intervals of 120 degrees Connected to the annular top of the combustion chamber (7). 4. The flue gas circulation system of the flue gas impingement water cyclone type LNG heating gasifier according to claim 1, characterized in that the cone angle of the flue gas nozzle (11) is 16 degrees.

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