Waste heat boiler for recycling heat of petroleum coke calcination flue gas

Abstract

The utility model discloses a waste heat boiler used for recovering smoke heat of calcined petroleum coke, which comprises a flue, the flue comprises a front flue and a rear flue, the front flue is arranged vertically downwards, the rear flue is arranged vertically upwards, the lower parts of the front flue and the rear flue are connected through a switching flue to form U-shaped distribution, and the switching flue is arranged vertically upwards. A cooling chamber and a slag solidification pipe are sequentially arranged on the front flue from top to bottom, a superheater and a tail heating surface are sequentially arranged on the rear flue from bottom to top, and an ash hopper is arranged at the bottom of the switching flue. Compared with a traditional heat exchange system, the heat exchange system has the advantages that the phenomena of superheater coking, high-temperature corrosion and tail heating surface low-temperature corrosion caused by high-Na, high-Ca, high-S and dust-containing flue gas can be effectively relieved, the safety stability of the heating surface of the waste heat boiler is improved, and the service life of the heating surface of the waste heat boiler is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of waste heat boiler technology, and in particular to a waste heat boiler for recovering heat from flue gas from calcining petroleum coke. Background Technology

[0002] With the rapid development of society and the gradual improvement of industrial production levels, the types and numbers of waste heat boilers are also increasing. One such waste heat boiler is the one used to recover heat from the flue gas of calcined petroleum coke. Petroleum coke is a byproduct of the production of light oil products by cracking the feedstock oil in delayed coking units at high temperatures. The flue gas produced by calcining petroleum coke contains high levels of Na, Ca, S, and dust, which causes corrosion of the tail-end heating surfaces of traditional waste heat boilers, such as superheaters and economizers. This leads to coking and bridging on the heating surface, affecting the service life of the waste heat boiler's heating surfaces. Utility Model Content

[0003] To solve the above-mentioned technical problems, this utility model designs a waste heat boiler for recovering heat from calcined petroleum coke flue gas.

[0004] The present invention adopts the following technical solution:

[0005] A waste heat boiler for recovering heat from calcined petroleum coke flue gas includes a flue, which comprises a front flue and a rear flue. The front flue is arranged vertically downwards, and the rear flue is arranged vertically upwards. The front and rear flues are connected by a transition flue to form a U-shaped distribution. A cooling chamber and a slag-collecting tube are arranged sequentially from top to bottom on the front flue, and a superheater and a tail heating surface are arranged sequentially from bottom to top on the rear flue. An ash hopper is arranged at the bottom of the transition flue.

[0006] Preferably, the waste heat boiler is equipped with soot blowing devices corresponding to the cooling chamber and the tail heating surface.

[0007] Preferably, the cooling chamber is composed of membrane water-cooled walls. The furnace structure, which is 50%-60% larger than that of conventional waste heat boilers, reduces the flue gas velocity, facilitating the settling of dust particles in the flue gas.

[0008] Preferably, the superheater adopts a bare tube structure with a lateral pitch greater than 160mm and is arranged below the rear flue. The flue gas after the slagging tube enters the superheater through the large-angle flue, reducing the flue gas temperature and velocity in the superheater, which is beneficial for the settling of dust particles and prevents superheater bridging and blockage.

[0009] Preferably, the slag-forming tube is arranged below the cooling chamber. By adjusting the area of ​​the slag-forming tube, the temperature of the flue gas below the slag-forming tube can be adjusted. Controlling the temperature of the flue gas below the slag-forming tube to be below 800°C ensures that the temperature of the flue gas entering the superheater is below the ash melting point, thus mitigating high-temperature corrosion, preventing slag formation on the superheater and the tail heating surface, and further removing dust from the flue gas.

[0010] Preferably, the ash hopper has a rectangular cross-sectional shape and is arranged below the waste heat boiler.

[0011] Preferably, the tail heating surface includes an economizer and an air preheater.

[0012] The flue gas from calcined petroleum coke enters the cooling chamber from the upper part of the front wall of the waste heat boiler. Dust particles settle in the air duct cooling chamber. After initial cooling, the flue gas exchanges heat with the slag-forming tubes. Further cooled, the flue gas makes a 180° turn before entering the superheater and the tail-end heating surfaces, heating the working fluid in the heating surfaces and lowering the exhaust gas temperature. Ash particles in the cooling chamber and heating surfaces fall into the ash hopper below and are discharged outside the furnace by the soot blowing device. The sulfur content in the flue gas after passing through the cooling chamber, slag-forming tubes, and superheater is significantly reduced, mitigating low-temperature corrosion of the tail-end heating surfaces. For waste heat boilers recovering heat from calcined petroleum coke flue gas, this system effectively mitigates superheater coking and high-temperature corrosion caused by high Na, high Ca, high S, and dust-laden flue gas, as well as low-temperature corrosion of the tail-end heating surfaces, improving the safety, stability, and service life of the waste heat boiler's heating surfaces.

[0013] The beneficial effects of this utility model are as follows: Compared with traditional heat exchange systems, this utility model adopts a waste heat boiler for recovering heat from calcined petroleum coke flue gas. This system can effectively reduce superheater coking and high-temperature corrosion caused by high Na, high Ca, high S and dust-containing flue gas, as well as low-temperature corrosion of the tail heating surface, thereby improving the safety stability and service life of the waste heat boiler heating surface. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model;

[0015] In the diagram: 1. Cooling chamber, 2. Slag tube, 3. Ash hopper, 4. Superheater, 5. Tail heating surface. Detailed Implementation

[0016] The technical solution of this utility model will be further described in detail below through specific embodiments and with reference to the accompanying drawings:

[0017] Example: Figure 1As shown, a waste heat boiler for recovering heat from calcined petroleum coke flue gas includes a cooling chamber 1, slag-collecting tubes 2, an ash hopper 3, a superheater 4, a soot blowing device, and a tail-end heating surface 5. The cooling chamber is composed of membrane water-cooled walls and employs a large-section furnace structure 50%-60% larger than conventional waste heat boilers, reducing flue gas velocity and facilitating the settling of dust particles in the flue gas. The slag-collecting tubes are arranged below the cooling chamber. By adjusting the area of ​​the slag-collecting tubes, the flue gas temperature below the tubes is adjusted, controlling it to be below 800℃. This ensures that the flue gas temperature entering the superheater is below the ash melting point, mitigating high-temperature corrosion, preventing slagging on the superheater and tail-end heating surface, and further removing dust from the flue gas. The superheater uses a bare tube structure with a lateral pitch greater than 160mm and is arranged below the second flue. The flue gas after the slag-collecting tubes enters the superheater through a transfer flue, reducing the superheater's flue gas temperature and velocity, facilitating dust particle settling, and preventing superheater bridging and blockage. The ash hopper, with a rectangular cross-section, is located below the waste heat boiler and serves to collect ash particles from the flue gas in the boiler's cooling chamber and heating surfaces, discharging them outside the boiler. The waste heat boiler is equipped with soot blowing devices at appropriate locations to remove ash particles adhering to the water-cooled walls and heating surfaces. The superheater outlet is connected to the inlet of the tail heating surface, where economizers, air preheaters, and other tail heating surfaces are arranged according to design requirements to heat the working fluid and reduce the exhaust gas temperature.

[0018] The working principle of this invention is as follows: The flue gas from calcining petroleum coke enters the cooling chamber from the upper part of the front wall of the waste heat boiler. Dust particles settle in the air duct cooling chamber. After initial cooling, the flue gas exchanges heat with the slag-forming tubes. After further cooling, the flue gas turns 180° and enters the superheater and the tail heating surface, heating the working fluid in the heating surface and reducing the exhaust gas temperature. The ash particles in the cooling chamber and heating surface fall into the ash hopper below and are discharged outside the furnace under the action of the soot blowing device.

[0019] Compared with traditional heat exchange systems, this invention can effectively mitigate superheater coking and high-temperature corrosion caused by high Na, high Ca, high S and dust-laden flue gas, as well as low-temperature corrosion of the tail heating surface, thereby improving the safety, stability and service life of the waste heat boiler heating surface.

[0020] The embodiments described above are merely preferred solutions of this utility model and are not intended to limit this utility model in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.

Claims

1. A waste heat boiler for recovering heat from flue gas from calcining petroleum coke, comprising a flue, characterized in that, The flue includes a front flue and a rear flue. The front flue is arranged vertically downwards, and the rear flue is arranged vertically upwards. The front flue and the rear flue are connected by a transition flue to form a U-shaped distribution. The front flue has a cooling chamber and a slag condensation tube arranged from top to bottom. The rear flue has a superheater and a tail heating surface arranged from bottom to top. The bottom of the transition flue has an ash hopper.

2. A waste heat boiler for recovering heat from calcined petroleum coke flue gas according to claim 1, characterized in that, The waste heat boiler is equipped with soot blowing devices corresponding to the cooling chamber and the tail heating surface.

3. A waste heat boiler for recovering heat from calcined petroleum coke flue gas according to claim 1, characterized in that, The cooling chamber is composed of membrane water-cooled walls.

4. A waste heat boiler for recovering heat from calcined petroleum coke flue gas according to claim 1, characterized in that, The superheater adopts a bare tube structure with a lateral pitch greater than 160mm and is located below the rear flue.

5. A waste heat boiler for recovering heat from calcined petroleum coke flue gas according to claim 1, characterized in that, The slag-forming pipe is arranged below the cooling chamber, and the flue gas temperature below the slag-forming pipe can be adjusted by adjusting the area of ​​the slag-forming pipe.

6. A waste heat boiler for recovering heat from calcined petroleum coke flue gas according to claim 1, characterized in that, The ash hopper has a rectangular cross-section and is located below the waste heat boiler.

7. A waste heat boiler for recovering heat from calcined petroleum coke flue gas according to claim 1, characterized in that, The tail heating surface includes an economizer and an air preheater.

Images