Requirements for the hottest waste gas purificatio

Requirements for waste gas purification and environmental protection equipment: 4+1

since the promulgation of the Cleaner Production Promotion Law of the people's Republic of China, our metal packaging industry should implement cleaner production according to law, improve resource utilization, reduce and avoid the generation of pollutants, protect and improve the environment. Time is pressing and the situation is grim. On the one hand, the state is strengthening the implementation of environmental protection laws and regulations. On the other hand, many of our iron printing enterprises do produce waste gas in production, which has not been effectively purified and treated. Under the current conditions, it is a better solution for iron printing enterprises to install waste gas purification and environmental protection equipment in the coating drying room. However, many enterprises have various doubts and views because they need to consume more energy and the product efficiency of some manufacturers has yet to be confirmed. Through this article, I want to introduce to you the requirements and relevant data on the installation of waste gas purification and environmental protection equipment at home and abroad in recent years. The waste gas purification and environmental protection equipment that can achieve the dual effects of environmental protection and energy saving is the most ideal and successful. Therefore, I propose the technical goal of 4+1 waste gas purification and environmental protection equipment for your reference and discussion

1. The content of 4+1

4 is:

1. The prediction result of exhaust gas purification effect meets the qb/national environmental protection standard under the condition of smokeless and tasteless

2. The heat emitted by waste gas purification and environmental protection equipment should be recycled and fully utilized

3. The heat emitted by environmental protection equipment should be controllable when used in iron printing and coating drying rooms, with a general accuracy of 3 ℃

4. Do not affect product quality

+1 yes:

the operating system of waste gas treatment environmental protection equipment and the operating system of the drying room are independent and can be controlled mutually, which is conducive to production scheduling and the normal operation of the drying room

it should be noted that after the emission of the environmental protection equipment for waste gas purification of the coating production line is recovered, in addition to supplying the heat of its own drying room through the heat exchanger system, the surplus can provide heat source for another iron printing drying room, which can reduce the heat source consumption of the iron printing drying room, and even completely turn off its heating system, which is commonly known as "one for two"

II. Introduction to the types and principles of waste gas purification and environmental protection equipment

the effective method of purifying waste gas in the iron printing industry at home and abroad is combustion method. There are flame combustion (direct combustion), thermal combustion, 3 Catalytic combustion and other types in the experimental process. Due to the low concentration of paint waste gas in the iron printing industry, it does not have the ability to make its own fuel purification. Therefore, only the combustion methods of the latter two can be introduced

thermal combustion (also known as incineration method)

depends on the heat generated by the combustion of auxiliary fuel (burner) to improve the temperature of exhaust gas and vaporize the components containing hydrocarbons in exhaust gas. Decomposition into harmless carbon dioxide and steam. For the iron printing industry, in order to achieve the ideal purification effect, it is necessary to design an incinerator that meets the capacity of the drying room, the baking process and the circulating air volume, that is, to achieve the three T conditions of heat: the reaction temperature in the furnace is about 760 ℃, and the residence time of the waste gas from the real source at this temperature Only when the exhaust gas is well mixed with oxidation can the exhaust gas be fully purified. Therefore, there should be a reasonable plan for different specifications of drying rooms and different paint varieties. Although thermal combustion is the most thorough method to purify waste gas, it is necessary to recycle heat to purify waste gas at a high temperature of 760 ℃ in order to reflect the practicality and economy of environmental protection equipment

catalytic combustion method

uses the catalyst in the combustion of exhaust gas to accelerate the reaction speed of exhaust gas decomposition, so that when the exhaust gas passes through the catalyst layer, it only needs 250 ~ 400 ℃ to purify the exhaust gas, which has obvious economy. Therefore, the design of catalytic combustion method must be aimed at different drying rooms and coatings, so that the variety and dosage of high-efficiency catalyst and the concentration of exhaust gas in the catalytic chamber are mutually matched, so as to fully purify the exhaust gas. Generally, the composition of catalyst is divided into three parts: active component, cocatalyst and carrier. The active component is the main body of the catalyst, without which the catalytic reaction cannot be completed. The most ideal active component is platinum, palladium and other precious metals, and then nickel, cobalt and other transition non precious metals. They have long service life, high activity, and do not have the required activity when the cocatalyst exists alone. However, when it coexists with the former, it can improve the activity of active components. The carrier plays a supporting role for the above catalyst, so that the catalyst has a suitable shape and particle size, has a large specific surface area, is conducive to reaction, heat transfer and dilution, and extends the service life of the catalyst. The carrier can be sheet, honeycomb, granular, columnar, etc. Therefore, the selection and arrangement of catalysts are very important, but in the process of purifying exhaust gas, the activity of catalysts always decreases gradually with the passage of time, that is, what we call catalyst aging or poisoning, because the long-term use of catalysts at high temperature will cause grain growth, melting phenomenon to occur, and the decline of specific surface area will eventually fail. Therefore, using this method to melt exhaust gas, Catalyst replacement always occurs

III. comparison between combustion method and catalytic combustion method

these two methods are the most concerned and commonly used methods in iron printing plants at present

incineration method: with simple structure and convenient management, it is the most thorough method to purify waste gas, which is widely used at home and abroad. However, since this method purifies waste gas at a high temperature of 750 ~ 800 ℃, the collection and utilization of heat is the key technical basis, otherwise, it will lose practical value. At present, the country 3 The incinerator in the standard configuration problem has been able to recycle heat for production, so as to achieve the purpose of one driving two (the original two drying rooms and four combustion chambers are out of use), which depends on the specific situation of each iron printing plant

catalytic combustion method: through the catalytic layer, the purification temperature of waste gas can be only 250 ~ 400 ℃, which is more energy-saving than incineration method. However, if heat recovery is not carried out, the energy consumption of the catalytic furnace plus the energy consumption of the two combustion chambers of the original paint drying room will certainly increase the production cost of the iron printing plant. At present, there are catalytic environmental protection furnaces in China that can carry out one by one heat recovery (the two combustion chambers in the paint drying room are out of use), which is a gratifying phenomenon. If the service life of the catalyst can be extended to more than two years, it will be more practical. In addition, strengthening the management of the catalytic environmental protection furnace and avoiding the catalyst from contacting sulfur, iron and other substances are important measures to prolong the service life of the catalyst

the above two combustion methods have one thing in common, which is to make full use of the heat generated by the oxidation and decomposition of exhaust gas to provide the temperature needs of the combustion chamber. Therefore, the high concentration of waste gas is conducive to saving energy consumption. It is hoped that the best condition is that all iron printing plants try their best to make the coating iron production line full of tasks

IV. relevant data

the energy consumption of the 33 meter long paint drying room is 350000 ~ 400000 kcal/h

the energy consumption of the 27 meter long iron printing drying room is 250000 ~ 300000 kcal/h

if kerosene is used as fuel, and the calorific value of kerosene is 10000 kcal/kg, the kerosene consumption of the two drying rooms is 60 ~ 70kg/h

therefore, in the case of one driving two, the waste gas purification and environmental protection equipment is an ideal environmental protection equipment with an energy consumption of 700000 kcal/h, achieving the dual effect of environmental protection and energy saving