CN107218601A - A kind of flame temperature control low nitrogen burning method and system for ceramic roller kiln - Google Patents

Abstract

The invention discloses a flame temperature-controlled low-nitrogen combustion method and system for a ceramic roller kiln, including a low-nitrogen burner and an air distribution system. After industrial site detection, most of the _NOx in the ceramic roller kiln is direct combustion For the thermal _NOx generated, the present invention installs a low-nitrogen burner and reduces the flame temperature through the pre-distribution air system, thereby reducing the amount of thermal _NOx produced, so as to achieve the purpose of _NOx emission reduction. The invention combines the technology of the ceramic production line and the characteristics of _NOx generation, uses the low-nitrogen burner to reduce the emission of _NOx , has a simple transformation process, and has no operating cost, and is a new type of ceramic flue gas pollutant treatment technology.

Description

A flame temperature-controlled low-nitrogen combustion method and system for ceramic roller kilns

technical field

The invention belongs to the technical field of ceramic production, in particular to a flame temperature-controlled low-nitrogen combustion method and system for a ceramic roller kiln.

Background technique

With the rapid development of my country's ceramic industry, the total amount of nitrogen oxides emitted during the ceramic production process is increasing, making the ceramic industry another major nitrogen oxide emitter after thermal power generation, automobile exhaust, and cement industry. . A large amount of nitrogen oxide emissions has a major adverse impact on the quality of the atmospheric environment and the earth's ecology, and has gradually become one of the main constraints on the sustainable development of the ceramic industry. At present, there are two mature denitrification processes, SNCR and SCR.

The operating temperature window of SNCR denitrification technology is 850-1100°C. From the point of view of the firing process of the kiln, this process can be used as a denitrification technology. However, considering that the denitrification technology may have a greater impact on the quality of ceramic production after it is put into operation . No enterprise is willing to try. Therefore, this technology has no running performance in ceramic factories.

SCR technology is to use flue gas reheating equipment after the flue gas is discharged from the kiln. It needs to heat the flue gas to 330 ° C ~ 380 ° C, and then enter the SCR reactor with a catalyst for denitrification treatment. After the treatment, the flue gas can be replaced After heating or other processes, it enters the original flue and is discharged. Since the ceramic kiln flue gas is relatively pure and has low dust content, the catalyst can be a honeycomb catalyst with a small pore size and a large specific surface area. The selection of denitrification reducing agent is similar to that of SNCR technology. This technology is mature, and the denitrification efficiency is guaranteed, but the project volume is huge, and the investment and use costs are relatively large.

At present, most of the fuel used in ceramic roller kilns is producer gas. The NOx content in generator gas is as low as 30-50 mg/Nm ³ through field tests, and the NO _x content once rose to _300-300 mg/Nm 3 after entering the ceramic roller kiln. 350mg/Nm ³ . According to the analysis, the current ceramic kiln mostly adopts the direct combustion method without primary air, the flame temperature is high, and a large amount of combustion-type NO _X is produced, resulting in high NO _X emission in the roller kiln.

Contents of the invention

In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a flame temperature-controlled low-nitrogen combustion method and system for ceramic roller kilns, which have the characteristics of low investment, convenient transformation, and no operating cost.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A flame temperature-controlled low-nitrogen combustion method for a ceramic roller kiln, comprising the steps of:

Step 1: Install low-nitrogen burners in the ceramic roller kiln;

The second step: distribute air to the low-nitrogen burner through the primary fan, and adopt graded air distribution to reduce the temperature of the combustion flame and the supply of oxygen, so that the flame burns in a reducing atmosphere, thereby reducing the formation of NOx;

Step 3: Use the secondary fan to mix and blow the burned gas in the air distribution system, so that the gas becomes an oxidizing atmosphere and prevents the influence of the reducing atmosphere on the fired ceramics;

Step 4: Detect the mixed gas temperature through the temperature monitoring system;

Step 5: The temperature detection system feeds back the detected temperature to the DCS system;

Step 6: The DCS system controls the air distribution fan to make the system reach the preset temperature to ensure the firing process of the roller kiln.

The low-nitrogen burner of the present invention supports multi-stage air distribution, and the air distribution is performed by a primary fan, which can automatically adjust the total air volume and the air distribution ratio of each level, so as to reduce the temperature of the combustion flame and the oxygen supply, so that the flame is Combustion in a reducing atmosphere reduces the amount of NOx produced.

The temperature monitoring system detects the gas after combustion and the mixed gas of the secondary air in real time, and transmits the data to the DCS system. The DCS system receives the data of the temperature monitoring system and compares it with the preset value, and controls the secondary air distribution system through the comparison result The size of the damper is used to realize the real-time monitoring of the temperature.

The present invention is a flame-controlled low-nitrogen combustion system for a ceramic roller kiln, which includes several low-nitrogen burners 4 arranged in a ceramic roller kiln, and each low-nitrogen burner 4 passes through a gas branch pipe and a gas main pipe from a gas station Docking, each low-nitrogen burner 4 is respectively connected to the primary fan 1 through the primary air branch pipe and the primary air main pipe, the combustion gas outlet of the low-nitrogen burner 4 is connected to the mixing chamber 7, and the mixing chamber 7 is connected to the secondary fan 5.

An electric valve one 3 for controlling the gas flow is installed on the gas branch pipe, and an electric valve two 2-1 and an electric valve three 2-2 for adjusting the total air volume and the air volume ratio of each level are installed on the primary air branch pipe to achieve The purpose of reducing the combustion temperature to form a local reducing atmosphere is to finally reduce the amount of NOx produced.

The quantity of the mixing chamber 7 is consistent with the low-nitrogen burner 4, one-to-one correspondence, each mixing chamber 7 is connected with the secondary fan 5 through the secondary air branch pipe and the secondary air main pipe respectively, and each secondary air branch pipe is installed There is an electric valve 6, and the electric valve 6 is used to adjust the air volume and mix the combustion air to reach the required temperature of the system.

The system of the present invention can also include a temperature measurement system 8 arranged at the rear end of the mixing chamber 7 for monitoring the temperature of the mixed air, the monitoring data of the temperature measurement system 8 is fed back to the DCS system 9 in real time, and the DCS system 9 compares the preset value to the The fans and valves are regulated to realize the automatic adjustment of the system.

Compared with prior art, the beneficial effect of the present invention is:

1) The transformation is simple.

2) No operating costs.

3) Easy to operate.

To sum up, the denitrification efficiency of the present invention can reach more than 50%, the control is simple, the investment is small, and there is no operating cost.

Description of drawings

Fig. 1 is a block diagram of the flue gas flue gas denitrification process of the present invention.

Fig. 2 is a structural schematic diagram of Form 1 of the flue gas denitrification system of the present invention.

detailed description

The implementation of the present invention will be described in detail below in conjunction with the drawings and examples.

As shown in Figure 1, a kind of method for the flame temperature control low-nitrogen combustion technology of ceramic roller kiln comprises the following steps:

Step 1: Install low-nitrogen burners in the ceramic roller kiln;

The second step: distribute air to the low-nitrogen burner through the primary fan, and adopt graded air distribution to reduce the temperature of the combustion flame and the supply of oxygen, so that the flame burns in a reducing atmosphere, thereby reducing the formation of NOx;

Step 3: Use the secondary fan to mix and blow the burned gas in the air distribution system, so that the gas becomes an oxidizing atmosphere and prevents the influence of the reducing atmosphere on the fired ceramics;

Step 4: Detect the mixed gas temperature through the temperature monitoring system;

Step 5: The temperature detection system feeds back the detected temperature to the DCS system;

Step 6: DCS controls the air distribution fan to make the system reach the preset temperature to ensure the firing process of the roller kiln.

The installed burner is a low-nitrogen burner with multi-stage air distribution. The air distribution is carried out by a primary fan, which can automatically adjust the total air volume and the air distribution ratio of each level, so as to reduce the temperature of the combustion flame and the supply of oxygen. The flame burns in a reducing atmosphere, thereby reducing the amount of NOx produced.

The temperature monitoring system detects the gas after combustion and the mixed gas of the secondary air in real time, and transmits the data to the DCS system. The DCS system receives the data of the temperature monitoring system and compares it with the preset value, and controls the secondary air distribution system through the comparison result The size of the damper is used to realize the real-time monitoring of the temperature.

The present invention also provides a corresponding system, including the following forms.

As shown in Figure 2, it is one of the forms of the system of the present invention:

The gas from the gas station is transported to the side of the roller kiln through the pipeline, and the gas branch pipe is connected with the low-nitrogen burner 4. The electric valve 1 3 is installed on the gas branch pipe to control the gas flow; the primary fan 1 passes through the main pipe and the primary air branch pipe It is connected with the low-nitrogen burner 4, and the electric valve 2-1 and the electric valve 3 2-2 are installed on the primary air branch pipe to adjust the total air volume and the air volume ratio of each level, so as to reduce the combustion temperature and form a local reducing atmosphere to finally reduce the formation of NOx Quantitative purpose.

The combusted gas enters the mixing chamber 7, and the secondary fan 5 connects with the mixing chamber 7 through the main pipe and the branch pipe. The electric valve 46 is set on the branch pipe to adjust the air volume and mix the combustion air to achieve the temperature required by the system.

A temperature measurement system 8 is installed at the back end of the mixing chamber to monitor the temperature of the mixing air and feed back the data to the DCS system 9 in real time. The DCS system controls the fans and valves by comparing the preset values to realize automatic adjustment of the system.

Claims (7)

1. A flame temperature-controlled low-nitrogen combustion method for ceramic roller kiln, is characterized in that, comprises the steps: Step 1: Install low-nitrogen burners in the ceramic roller kiln; The second step: distribute air to the low-nitrogen burner through the primary fan, and adopt graded air distribution to reduce the temperature of the combustion flame and the supply of oxygen, so that the flame burns in a reducing atmosphere, thereby reducing the formation of NOx; Step 3: Use the secondary fan to mix and blow the burned gas in the air distribution system, so that the gas becomes an oxidizing atmosphere and prevents the influence of the reducing atmosphere on the fired ceramics; Step 4: Detect the mixed gas temperature through the temperature monitoring system; Step 5: The temperature detection system feeds back the detected temperature to the DCS system; Step 6: The DCS system controls the air distribution fan to make the system reach the preset temperature to ensure the firing process of the roller kiln. 2. The flame temperature-controlled low-nitrogen combustion method for ceramic roller kilns according to claim 1, wherein the low-nitrogen burner supports multi-stage air distribution, and the air distribution is performed by a primary fan to support the total air volume Adjustment and proportional adjustment of air distribution at all levels. 3. The flame temperature-controlled low-nitrogen combustion method for ceramic roller kiln according to claim 1, characterized in that, the DCS system accepts the data of the temperature monitoring system and compares it with the preset value, and controls the secondary temperature by the comparison result. The size of the damper of the air distribution system. 4. A flame-controlled low-nitrogen combustion system for a ceramic roller kiln, characterized in that it includes several low-nitrogen burners (4) arranged in the ceramic roller kiln, and each low-nitrogen burner (4) passes through the gas The branch pipe is connected with the gas main pipe from the gas station, each low-nitrogen burner (4) is connected with the primary fan (1) through the primary air branch pipe and the primary air main pipe respectively, and the combustion gas outlet of the low-nitrogen burner (4) is connected to the mixing chamber ( 7), the mixing chamber (7) is connected to the secondary fan (5). 5. The flame temperature-controlled low-nitrogen combustion system for ceramic roller kilns according to claim 4, wherein an electric valve (3) for controlling gas flow is installed on the gas branch pipe, and the primary air Electric valve two (2-1) and three electric valves (2-2) are installed on the branch pipes to adjust the total air volume and the air volume ratio of each level, so as to reduce the combustion temperature and form a local reducing atmosphere to finally reduce the amount of NOx generated. 6. The flame temperature-controlled low-nitrogen combustion system for ceramic roller kiln according to claim 4, characterized in that, the number of the mixing chamber (7) is consistent with the low-nitrogen burner (4), one-to-one correspondence, Each mixing chamber (7) is respectively connected to the secondary fan (5) through the secondary air branch pipe and the secondary air main pipe, and the electric valve (6) is installed on each secondary air branch pipe, and the air volume is adjusted through the electric valve (6). Mix with the combustion air to reach the required temperature of the system. 7. The flame temperature-controlled low-nitrogen combustion system for ceramic roller kilns according to claim 4, is characterized in that, it also includes a temperature measuring system (8) for monitoring the temperature of the mixed air arranged at the rear end of the mixing chamber (7) ), the monitoring data of the temperature measurement system (8) is fed back to the DCS system (9) in real time, and the DCS system (9) regulates the fans and valves by comparing preset values to realize automatic adjustment of the system.