CN204704834U - Exhaust-heat boiler flue gas low temperature dedusting redox the two poles of the earth absorption process denitration treatment system - Google Patents

Abstract

A waste heat boiler flue gas low-temperature dedusting oxidation-reduction two-stage absorption denitrification treatment system, which includes a waste heat boiler, an electrostatic precipitator, an induced draft fan, a first absorption tower, a second absorption tower, a chimney, and a waste heat flue gas transmission pipeline, said The waste heat boiler is provided with a flue gas inlet and a flue gas outlet, the flue gas inlet is connected to the waste heat conveying pipe, the flue gas outlet is connected to the inlet of the electrostatic precipitator, the outlet of the electrostatic precipitator is connected to the inlet of the induced draft fan, and the induced draft fan passes through the provided The outlet of the induced draft fan is connected to the inlet of the first absorption tower, and the first absorption tower is connected to the inlet of the second absorption tower through the outlet of the first absorption tower, and the outlet of the second absorption tower is connected to the outlet of the second absorption tower. It is connected to the waste heat flue gas conveying pipeline, and the waste heat flue gas conveying pipeline is connected to the chimney.

Description

Waste heat boiler flue gas low-temperature dust removal redox bipolar absorption method denitrification treatment system

technical field

The utility model designs a denitrification treatment system of waste heat flue gas low-temperature dust removal redox bipolar absorption method.

Background technique

Waste heat is energy that has not been utilized in energy utilization equipment, including waste heat of high-temperature exhaust gas, waste heat of cooling medium, waste heat of waste steam and waste water, waste heat of high-temperature products and slag, waste heat of chemical reactions, waste heat of combustible waste gas and liquid, and waste heat. During the period, the country has comprehensively promoted waste heat recovery and utilization technologies in industries with rich waste heat resources such as steel, glass, non-ferrous metals, chemicals, and building materials. Moreover, with the rapid development of the national economy, the country has higher and higher requirements for environmental protection. While promoting the recovery and utilization of waste heat, the clean emission of exhaust gas from waste heat recovery boilers has also received increasing attention.

Taking the production of glass furnaces as an example, on April 2, 2011, the Ministry of Environmental Protection and the General Administration of Quality Inspection and Quarantine of the People's Republic of China issued the "Emission Standards for Air Pollutants in the Flat Glass Industry" and implemented them on October 1, 2011. Taking the data of a company's float flat glass melting furnace as a prototype, the glass furnace fuel is natural gas, and its flue gas emission data is shown in the table below.

serial number parameter name unit 1# kiln 2# kiln 3# Kiln 1 model t/d 250 500 600 2 exhaust temperature ℃ 480 480 480 3 Flue gas volume Nm ³ /h 59000 90000 108000 4 particulates mg/ ^Nm3 3000 3000 3000 5 SO ₂ mg/ ^Nm3 <200 <200 <200 6 NO _X mg/ ^Nm3 2350 3300 3750 7 HCL mg/ ^Nm3 <130 <130 <130 8 Fluoride mg/ ^Nm3 <5 <5 <5

It can be seen from the above table that the particles and NOX in the flue gas of the glass kiln of this enterprise have greatly exceeded the national standard, and a suitable denitrification and dust removal system needs to be selected for treatment.

At present, the research directions of denitrification in China mainly include: low-nitrogen combustion technology, oxygen-enriched combustion technology, SNCR, SCR and redox absorption method.

Both low-nitrogen combustion technology and oxygen-enriched combustion technology belong to the control of combustion temperature to reduce the formation of thermal nitrogen oxides. Due to the non-combustion characteristics of waste heat boilers, low-nitrogen combustion technology and oxygen-enriched combustion technology are not suitable for glass kilns.

SNCR is a relatively mature denitrification technology with a wide range of applications. SNCR denitrification technology adopts a high-temperature reaction method, which requires the flue gas to be in the temperature range of 950~1100°C and have sufficient reaction time for the original reaction between the reducing agent and NOx to form harmless of nitrogen and water. Since there is no temperature zone between 950 and 1100°C in the waste heat boiler, SNCR is not suitable for the denitrification of the waste heat boiler.

The reaction conditions of SCR denitration technology are easy to control, and can achieve high denitration efficiency (up to 90%). SCR denitration method has become a relatively mature mainstream technology for flue gas denitrification at home and abroad. Due to the main process of the glass kiln, the waste heat flue gas has a large dust content and a small particle size. The dust contains alkali metals and alkaline earth metals that can cause catalyst poisoning, which can easily cause the micropores of the catalyst to be blocked and cause catalyst poisoning. Therefore, it must be denitrified. Dust before. For the 350℃~400℃ high-temperature dust collector, due to the influence of thermal expansion, the operation state of the high-temperature dust collector is unstable, which often leads to the decommissioning of the entire system, and the waste heat flue gas must be discharged from the bypass, which is very harmful to the environment and wastes waste heat resources.

Contents of the invention

The purpose of the utility model is to provide a low-temperature dedusting redox bipolar absorption denitrification treatment system for waste heat flue gas. It is not only suitable for flue gas purification treatment of waste heat boilers supporting glass kilns, but also suitable for flue gas purification treatment of other high-dust waste heat boilers with an initial temperature of ~500 °C.

The technical solution of this utility model is: a waste heat boiler flue gas low-temperature dedusting redox bipolar absorption denitrification treatment system, which includes a waste heat boiler, an electrostatic precipitator, an induced draft fan, a first absorption tower, a second absorption tower and a chimney, and The waste heat flue gas conveying pipeline, the waste heat boiler is provided with a flue gas inlet and a flue gas outlet, the flue gas inlet is connected to the waste heat conveying pipe, the flue gas outlet is connected to the inlet of the electrostatic precipitator, and the outlet of the electrostatic precipitator is connected to the inlet of the induced draft fan. The induced draft fan is connected to the inlet of the first absorption tower through the outlet of the induced draft fan provided, and the first absorption tower is connected to the inlet of the second absorption tower through the outlet of the first absorption tower provided with, and the second absorption tower passes through The outlet of the provided second absorption tower is connected to the waste heat flue gas conveying pipe, and the waste heat flue gas conveying pipe is connected to the chimney.

The flue gas (about 480°C) enters the waste heat boiler, and after the waste heat is utilized in the waste heat boiler, the exhaust gas temperature is about 165°C. The exhaust smoke from the boiler passes through the electrostatic precipitator to reduce the dust concentration to below 50mg/Nm3. The flue gas after dedusting and purification enters the first-stage absorption tower through the induced draft fan, and the flue gas is fully contacted with the oxidized absorption liquid. After a relatively ideal mass transfer, part of the nitrogen oxides in the flue gas react with the absorption liquid. After being removed, after being treated by the primary absorption tower, not only a small amount of nitrogen oxides are removed, but also the oxidation degree of NOx in the flue gas (NO2/NOX concentration ratio) is increased, and then enters the secondary absorption tower, the flue gas The NOx is absorbed by the absorption liquid again, and the flue gas is effectively purified and then enters the chimney through the flue and is discharged at high altitude.

The beneficial effects of the utility model are: it is not only suitable for the flue gas purification treatment of waste heat boilers supporting glass kilns, but also suitable for the flue gas purification treatment of other high-dust waste heat boilers with an initial temperature of ~500°C. It has a simple structure and is safe and stable to use. , high utilization rate. Therefore, the utility model is worth promoting.

Description of drawings

Fig. 1 is a structural schematic diagram of an embodiment of the utility model.

Detailed ways

Below in conjunction with accompanying drawing, structure and principle of the present utility model are further described.

As shown in Figure 1, this embodiment is: a waste heat boiler flue gas low-temperature dedusting redox bipolar absorption denitrification treatment system, which includes a waste heat boiler 1, an electrostatic precipitator 2, an induced draft fan 3, a first absorption tower 4, a second Two absorption towers 5, chimneys 6, and waste heat flue gas conveying pipes 7, the waste heat boiler 1 is provided with a flue gas inlet and a flue gas outlet, the flue gas inlet is connected to the waste heat conveying pipe 7, and the flue gas outlet is connected to the inlet of the electrostatic precipitator 2, The outlet of the electrostatic precipitator 2 is connected to the inlet of the induced draft fan 2, and the induced draft fan 2 is connected to the inlet of the first absorption tower 4 through the outlet of the induced draft fan 2 provided, and the first absorption tower 4 is connected to the inlet of the first absorption tower 4 through the provided first absorption tower 4. The outlet of an absorption tower 4 is connected to the inlet of the second absorption tower 5, and the outlet of the second absorption tower 5 is connected to the waste heat flue gas pipeline 7 through the outlet of the second absorption tower 5, and the waste heat flue gas pipeline 7 is connected to the chimney 6.

When in use, high-temperature waste heat flue gas enters the waste heat boiler 1 to generate steam, which can be used for power generation or heat supply for production processes. At the same time, the exhaust temperature of the flue gas is reduced so that the flue gas can meet the operating conditions of the conventional electrostatic precipitator. The residual heat flue gas passes through the electrostatic precipitator to remove particulate matter and the residual heat flue gas reacts with the absorption liquid in the two-stage absorption tower to remove NOX. Make the flue gas of the waste heat boiler meet the emission standard.

Claims (1)

1. exhaust-heat boiler flue gas low temperature dedusting redox the two poles of the earth absorption process denitration treatment system, it comprises waste heat boiler, electrostatic precipitator, air-introduced machine, first absorption tower, second absorption tower and chimney, and smoke conveying duct, it is characterized in that: described waste heat boiler is provided with gas approach and exhanst gas outlet, gas approach connects waste heat conveyance conduit, exhanst gas outlet connects electrostatic precipitator import, the outlet of described electrostatic precipitator connects air-introduced machine import, described air-introduced machine is connected to the import on the first absorption tower again by the air-introduced machine outlet be provided with, described first absorption tower connects second absorption tower import by the first absorption tower outlet be provided with, described second absorption tower is connected to waste heat smoke conveying duct by the second absorption tower outlet be provided with, described waste heat smoke conveying duct connects chimney.