AU2021101477A4

AU2021101477A4 - A regenerative catalytic oxidation device with combined oxidation bed for ventilation air methane

Info

Publication number: AU2021101477A4
Application number: AU2021101477A
Authority: AU
Inventors: Jian LV; Mingming Mao
Original assignee: Shandong University of Technology; Shandong Vocational College of Industry
Current assignee: Shandong University of Technology; Shandong Vocational College of Industry
Priority date: 2021-03-23
Filing date: 2021-03-23
Publication date: 2021-06-24
Anticipated expiration: 2029-03-23

Abstract

The invention relates to a regenerative catalytic oxidation device with combined oxidation bed for ventilation air methane, which comprises a cylinder with two closed ends, an oxidation bed arranged at the center of the cylinder, a rotary reversal valve installed at the bottom of the oxidation bed, a blower, an induced fan and a throttle valve. There is a distance between the oxidation bed and the top plate of the cylinder to form the air collection cavity. The inlet of the rotary reversing valve is connected to the blower exhaust through the intake pipe connected with the throttle valve. The inlet of the rotary reversal valve is connected with a blower by an air intake pipe provided with a throttle valve. and the scavenging port of the rotary reversing valve is connected with the scavenging air pipe equipped with the induced fan and the throttle valve. The oxidation bed is composed of the catalytic bed and the heat regenerator attached to the upper and lower side of the catalytic bed. The rotary reversing valve includes the intake distribution plate, the exhaust distribution plate, the scavenging gas distribution plate, the rotary shaft and the motor. The oxidation device relies on the oxidation and heat release of coal mine ventilation air to realize self-heating maintenance operation, without external auxiliary heat source, and it can save energy and work stably and reliably.

Description

A regenerative catalytic oxidation device with combined oxidation bed for

ventilation air methane

TECHNICAL FIELD

The present invention belongs to the technical field of low-grade gas energy utilization,

and specifically relates to a regenerative catalytic oxidation device with combined

oxidation bed for ventilation air methane.

BACKGROUND

In the process of coal mine production, a large amount of ventilation is usually used

to dilute and discharge coal mine gas to produce ventilation air methane (VAM). Because

the volume concentration of exhaust gas is very low (generally in the range of 0.1% ~

0.75%), and the fluctuation range of air volume and volume concentration is large, it is

difficult to use the traditional burner for direct combustion, so the exhaust gas is often

directly discharged into the atmosphere. Methane, the main component of ventilation air

methane, is the second largest greenhouse gas after carbon dioxide. In China, more than 20

billion cubic meters of pure methane are emitted through coal mine ventilation every year,

which seriously pollutes the atmospheric environment and causes a huge waste of high

quality clean gas energy.

The main domestic and international technologies for utilizing ventilation air methane

as a primary fuel are thermal flow reversal reactor and catalytic flow reversal reactor, both

of which utilize the heat storage properties of the porous media oxidation bed and flow

switching technique to maintain the stable operation of the oxidizer and utilize the

exothermic heat of methane oxidation. The main difference is that catalytic flow reversal reactor adopts the catalyst, which reduces the temperature required for methane oxidation.

However, the switching flow, which is essential for flow reversal oxidation, leads to a

number of drawbacks, such as periodic fluctuations in the temperature field caused by the

reversal flow, which makes heat extraction more difficult and increases the thermal stress

on the ceramic heat accumulator. Some of the ventilation air methane escapes during the

reversal, which reduces the actual methane conversion rate. The reversal operation requires

high operational reliability of the reversal mechanism and makes the overall structure of

the plant complex, making assembly and maintenance difficult. The reversing operation

requires high operational reliability of the reversing mechanism and makes the overall

structure of the plant complex, making assembly and maintenance difficult. These

problems increase operating costs and limit the popularity of flow reversal oxidation

technology.

Rotary regenerative oxidation technology is widely used in the oxidation treatment of

industrial organic waste gas. It can be applied to preheat the inlet gas with continuous

rotating heat regenerator and recover the exhaust heat energy after oxidation. It can ensure

the stability of temperature field and the continuity of flow in the heat regenerator.

However, the current rotary heat regenerator (for example, CN 205424948 U) uses inert

porous medium heat regenerator to preheat and recover the inlet gas, and a separate

combustion chamber relies on the igniter to ignite the preheated to high temperature (about

800 °C). Moreover, the heat transfer intensity is low and the volume of the heat regenerator

is large. Most of the existing rotary regenerative combustion devices (such as CN

205535865 U authorized notice) adopt rotary reversing valve to realize the conversion

function of intake, exhaust and scavenging. However, the existing rotary reversing valve structure is complex, the valve body and the valve core are divided into several flow areas, the flow loss is larger, and the plane seal is used to separate the air intake, exhaust and scavenge areas, the friction force is larger, the drive motor energy consumption is increased, and compensation mechanism is often used to compensate the friction surface wear and increase the operation instability.

SUMMARY

The purpose of the invention is to make up for the deficiency of the existing rotary

regenerative catalytic oxidation device, and to provide a regenerative catalytic oxidation

device with combined oxidation bed for ventilation air methane, which has compact

structure, high operation efficiency and low energy consumption.

Technical scheme:

The regenerative catalytic oxidation device with combined oxidation bed for

ventilation air methane provided by this technical scheme comprises a cylinder (4) with

both ends closed, an oxidation bed arranged in the center of the cylinder (4), a rotary

reversal valve installed at the bottom of the oxidation bed, a blower (9), an induced fan (15)

and a throttle valve (10). A distance is left between the oxidation bed and the top plate of

the cylinder (4) to form the air collection cavity. The inlet of the rotary reversal valve is

connected with a blower (9) by an air intake pipe (11) provided with a throttle valve (10).

The exhaust port of the rotary reversing valve is connected with an exhaust pipe (17), which

is communicated with the scavenging port of the rotary reversing valve by a scavenging

pipe (16) provided with an induced fan (15) and a throttle valve (10).

The oxidation bed is composed of a catalytic bed (3) and a heat regenerator (2) attached to the upper and lower sides of the catalytic bed (3). A plurality of vertically arranged heaters (1) are installed at the air collection cavity, and the top end of the heater

(1) is fixed on the top plate of the cylinder (4). The rotary reversal valve comprises an

intake distribution plate (5), an exhaust distribution plate (7), an scavenging gas distribution

plate (8), a rotary shaft (13) and a motor (12), wherein the rotating shaft (13) is coaxial

with the cylinder (4). The rotary shaft (13) is installed on the bottom plate of the cylinder

(4) by the thrust bearing (14), the lower end of the rotary shaft (13) passes through the

cylinder (4) and is fixedly connected with the output end of the motor (12), and the upper

end of the rotary shaft (13) has a gap with the regenerative body (2).

The intake distribution plate (5), the exhaust distribution plate (7) and the scavenging

gas distribution plate (8) are horizontally and fixedly installed at the top, middle and lower

parts of the rotating shaft 13 respectively. The intake distribution plate (5), the exhaust

distribution plate (7) and the cylinder (4) form an air inlet cavity communicated with the

air intake pipe (11). The exhaust distribution plate (7), the scavenging gas distribution plate

(8) and the cylinder (4) form an exhaust cavity communicated with the exhaust pipe (17).

The scavenging gas distribution plate (8), the side wall of the cylinder (4) and the

bottom plate of the cylinder (4) form an air scavenge cavity communicated with the

scavenge pipe (16). A fan-shaped intake outlet (21), an exhaust inlet (22) and a scavenging

outlet (23) are arranged on the intake distribution plate (5), a fan-shaped exhaust outlet (24)

and a scavenging passage port (25) are arranged on the exhaust distribution plate (7), and

a fan-shaped scavenging inlet (26) are arranged on the scavenging gas distribution plate

(8), wherein the exhaust inlet (22) is directly above the exhaust outlet (24) while the sizes

of the two are equal, and the scavenging outlet 23 and the scavenging passage port 25 are both located directly above the scavenging inlet 26, and they are equal in size. The exhaust passage (6) is enclosed by two vertical planes and an outer arc surface connected between the exhaust inlet (22) and the exhaust outlet (24) and the side wall of the rotating shaft (13).

The scavenging channel (18) is enclosed by two vertical planes and an outer circular arc

surface connected between the scavenging inlet (26), the scavenging channel port (25) and

the scavenging outlet (23) and the side wall of the rotating shaft (13). The exhaust passage

(6) and the scavenging passage (18) have a distance from the side wall of the cylinder (4),

so that the rotating intake cavity and the exhaust cavity are connected with the intake pipe

(11) and the exhaust pipe (17).

The matrix of the catalytic bed (3) and the heat regenerator (2) are made of cordierite

honeycomb ceramics, the pores in the honeycomb ceramics are vertically arranged, and the

catalyst supported by the catalytic bed body (3) adopts Pt noble metal catalyst or Pd noble

metal catalyst.

The volume of the intake cavity and the exhaust cavity is equal, and the volume of the

scavenging cavity is 1 / 20 ~1 / 10 of the volume of the intake cavity or the exhaust cavity.

The intake outlet (21) is vertically installed with an intake seal bulkhead (20) on the

two straight edges of the intake outlet (21), and a scavenge seal baffle (19) is vertically

installed around the scavenge outlet (23), and a circumferential distance is left between the

intake outlet (21), the scavenge outlet (23) and the exhaust inlet (22).

Working principle:

At the beginning of device start-up, the heater in the air collection box at the top of

the oxidation bed starts to heat. The ventilation air of coal mine enters the air inlet cavity

through the air blower and throttle valve from the inlet pipe of the rotary reversing valve, then the air exits from the inlet of the intake distribution plate at the top of the intake cavity.

It enters into the air collecting box vertically through the oxidation bed, then flows back to

the heat regenerator after being heated by the heater in the gas collecting box, and passes

the heat to the heat regenerator, then exits from the lower end surface of the heat regenerator,

and returns from the exhaust inlet to the rotary reversing valve.

The gas then flows into the exhaust cavity along the exhaust passage and then exits

the exhaust pipe to the atmosphere. The motor drives the rotating shaft, the intake

distribution plate, the exhaust distribution plate and the scavenging gas distribution plate

to rotate, the air intake from the rotary reversing valve enters the oxidation bed and the

exhaust from the oxidation bed to the rotary reversing valve rotate synchronously, the

whole cycle of the oxidation bed is slowly heated by the exhaust gas to the catalytic

oxidation temperature of the exhaust gas (about 400 °C to 500 °C), and the exhaust gas

starts to oxidize heat and closes the heater in the oxidation bed. the device relies on the

oxidation and exothermic of exhaust gas to start self-heating maintenance operation. The

exhaust gas of the fan is drawn out from the exhaust gas and passes through the throttle

valve to the scavenging cavity of the rotary reversing valve from the scavenge pipe, enters

the heat regenerator along the vertical scavenging channel, sweeps away the residual

unoxidized ventilation air in the heat regenerator channel, and then enters the air collection

box and the post-oxidation exhaust gas convergence, passes down through the oxidation

bed together, and exhausts the exhaust passage of the rotary reversing valve and the-exhaust

passage-fe-hthe exhaust pipe to the atmosphere. The scavenging gas rotates

synchronously with the rotation of the scavenging gas distribution plate. Thus, under the

distribution of rotating parts of the rotary reversing valve, the process of air intake oxidation, scavenging and heat release in the oxidation bed is carried out in an orderly manner, and the oxidation bed is divided into the oxidation zone, the cleaning zone and the heat storage zone as a whole, and the three areas are rotated along the whole week to effectively complete the efficient oxidation of the coal mine ventilation air methane and the stable operation of self-heating.

Compared with the prior art, the invention has the following advantages and beneficial

effects that:

1. The combined oxidation bed has the advantages of higher heat transfer intensity

and efficiency, less heat exchange area and heat storage volume, smaller overall size and

more compact structure than the traditional heat regenerator.

2. Depending on the low-temperature catalytic oxidation ability of catalytic oxidation

bed for coal mine entilation air and the high heat storage and strong heat feedback ability

of honeycomb ceramic oxidation bed, the oxidation device can rely on the oxidation heat

release of coal mine ventilation air to realize self heating operation, without external

auxiliary heat source and saves energy.

3. The structure of the directional valve is simple and efficient. The smooth rotating

process of air intake, exhaust and scavenging is realized by the distribution of the intake

distribution plate 5, the exhaust distribution plate 7 and the scavenging gas distribution

plate 8. The flow loss is very small, the energy consumption of the driving motor is very

low, and the operation is stable.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 is the structural diagram of an embodiment of the present invention.

Fig. 2 is A-A sectional view of the structure of the embodiment shown in Fig. 1.

Fig. 3 is the structural diagram of the rotary reversal valve in the embodiment shown

in Fig. 1.

Fig. 4 is the structural diagram of the intake distribution plate in the embodiment

shown in Fig. 1.

Fig. 5 is the structural diagram of the exhaust distribution plate in the embodiment

shown in Fig. 1.

Fig. 6 is the structural diagram of the scavenging gas distribution plate in the

embodiment structure shown in Fig. 1.

Labels: 1: Heater 2: Heat regenerator 3: Catalytic bed 4: Cylinder 5: intake distribution

plate 6: ventilation air passage 7: Exhaust distribution plate 8:Scavenging gas distribution

plate; 9: Blower 10: Throttle valve 11: Air intake pipe 12: Motor 13: Rotary shaft 14: Thrust

bearing 15: Induced fan 16: Scavenging pipe 17: Exhaust pipe 18: Scavenging channel 19:

Scavenge seal baffle 20: Intake seal bulkhead 21: Inlet outlet 22: Exhaust inlet 23:

Scavenging outlet 24: Exhaust outlet 25: Scavenging channel port 26: Scavenging inlet.

DESCRIPTION OF THE INVENTION

The present invention will be further explained with reference to the accompanying

drawings by the embodiment shown in figures 1-6.

The rotary regenerative regenerative catalytic oxidation device with combined

oxidation bed for ventilation air methane-provided by this embodiment comprises a

cylinder (4) with both ends closed, an oxidation bed arranged in the center of the cylinder

(4), a rotary reversal valve installed at the bottom of the oxidation bed, a blower (9), an

induced fan (15) and a throttle valve (10). A distance is left between the oxidation bed and

the top plate of the cylinder (4) to form the air collection cavity. The ventilation air inlet of the rotary reversal valve is connected with a blower (9) by an air intake pipe (11) provided with a throttle valve (10). The exhaust port of the rotary reversing valve is connected with an exhaust pipe (17), which is communicated with the scavenging port of the rotary reversing valve by a scavenging pipe (16) provided with an induced fan (15) and a throttle valve (10).

The oxidation bed is composed of a catalytic bed (3) and a heat regenerator (2)

attached to the upper and lower sides of the catalytic bed (3). A plurality of vertically

arranged heaters (1) are installed at the air collection cavity, and the top end of the heater

intake distribution plate (5), an exhaust distribution plate (7), a scavenging gas distribution

plate (8), a rotary shaft (13) and a motor (12), Wherein the rotating shaft 13 is coaxial with

the cylinder 4. The rotary shaft (13) is installed on the bottom plate of the cylinder (4) by

the thrust bearing (14), the lower end of the rotary shaft (13) passes through the cylinder

(4) and is fixedly connected with the output end of the motor (12), and the upper end of the

rotary shaft (13) has a gap with the heat regenerator (2).

The intake distribution plate 5, the exhaust distribution plate 7 and the scavenging gas

distribution plate 8 are horizontally and fixedly installed at the top, middle and lower parts

of the rotating shaft 13 respectively. The intake distribution plate (5), the exhaust

bottom plate of the cylinder (4) form an air scavenge cavity communicated with the scavenge pipe (16). A fan-shaped air inlet outlet (21), an exhaust inlet (22) and a scavenging outlet (23) are arranged on the intake distribution plate (5), a fan-shaped exhaust outlet (24) and a scavenging passage port (25) are arranged on the exhaust distribution plate (7), and a fan-shaped scavenging inlet (26) are arranged on the scavenging gas distribution plate (8), wherein the exhaust inlet (22) is directly above the exhaust outlet (24) while the sizes of the two are equal, and the scavenging outlet 23 and the scavenging passage port 25 are both located directly above the scavenging inlet 26, and they are equal in size. The exhaust passage (6) is enclosed by two vertical planes and an outer arc surface connected between the exhaust inlet (22) and the exhaust outlet (24) and the side wall of the rotating shaft (13). The scavenging channel (18) is enclosed by two vertical planes and an outer circular arc surface connected between the scavenging inlet

(26), the scavenging channel port (25) and the scavenging outlet (23) and the side wall of

the rotating shaft (13). The exhaust passage (6) and the scavenging passage (18) have a

distance from the side wall of the cylinder (4), so that the rotating intake cavity and the

exhaust cavity are connected with the air intake pipe (11) and the exhaust pipe (17).

metal catalyst.

two straight edges of the intake outlet (21), and a scavenge seal baffle (19) is vertically installed around the scavenge outlet (23), and a circumferential distance is left between the intake outlet (21), the scavenge outlet (23) and the exhaust inlet (22).

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. The regenerative catalytic oxidation device with combined oxidation bed for

ventilation air methane, which comprises a cylinder (4) with both ends closed, an oxidation

bed arranged in the center of the cylinder (4), a rotary reversal valve installed at the bottom

of the oxidation bed, a blower (9), an induced fan (15) and a throttle valve (10). A distance

is left between the oxidation bed and the top plate of the cylinder (4) to form the air

collection cavity. The ventilation air inlet of the rotary reversal valve is connected with a

blower (9) by an air intake pipe (11) provided with a throttle valve (10). The exhaust port

of the rotary reversing valve is connected with an exhaust pipe (17), which is

communicated with the scavenging port of the rotary reversing valve by a scavenging pipe

(16) provided with an induced fan (15) and a throttle valve (10). The device is characterized

in the following content:

The oxidation bed is composed of a catalytic bed (3) and a heat regenerator (2)

plate (8), a rotary shaft (13) and a motor (12), wherein the rotary shaft (13) is connected

with the bottom plate of the cylinder (4). The rotary shaft (13) is installed on the bottom

plate of the cylinder (4) by the thrust bearing (14), the lower end of the rotary shaft (13)

passes through the cylinder (4) and is fixedly connected with the output end of the motor

(12), and the upper end of the rotary shaft (13) has a gap with the heat regenerator (2).

The intake distribution plate (5), the exhaust distribution plate (7) and the scavenging gas distribution plate (8) are horizontally and fixedly installed at the top, middle and lower parts of the rotating shaft 13 respectively. The intake distribution plate (5), the exhaust distribution plate (7) and the cylinder (4) form an air inlet cavity communicated with the air intake pipe (11). The exhaust distribution plate (7), the scavenging gas distribution plate

of the two are equal, and the scavenging outlet 23 and the scavenging passage port 25 are

both located directly above the scavenging inlet 26, and they are equal in size. The exhaust

passage (6) is enclosed by two vertical planes and an outer arc surface connected between

the exhaust inlet (22) and the exhaust outlet (24) and the side wall of the rotating shaft (13).

(11) and the exhaust pipe (17).

2. The regenerative catalytic oxidation device with combined oxidation bed for ventilation air methane according to claim 1, which is characterized in that the matrix of the catalytic bed (3) and the heat regenerator (2) are made of cordierite honeycomb ceramics, the pores in the honeycomb ceramics are vertically arranged, and the catalyst supported by the catalytic bed body (3) adopts Pt noble metal catalyst or Pd noble metal catalyst.

3. The regenerative catalytic oxidation device with combined oxidation bed for

ventilation air methane according to claim 1, which is characterized in that the volume of

the intake cavity and the exhaust cavity is equal, and the volume of the scavenging cavity

is 1 / 20 ~1 / 10 of the volume of the intake cavity or the exhaust cavity.

4. The regenerative catalytic oxidation device with combined oxidation bed for

ventilation air methane according to claim 1, which is characterized in that the intake outlet

(21) is vertically installed with an intake seal bulkhead (20) on the two straight edges of

the intake outlet (21), and a scavenge seal baffle (19) is vertically installed around the

scavenge outlet (23), and a circumferential distance is left between the intake outlet (21),

the scavenge outlet (23) and the exhaust inlet (22).

FIGURES

1/6 2021101477

Figure 1. The structural diagram of an embodiment of the present invention