Application of activated carbon in hydrogen sulfide removal

It is important to treat hydrogen sulfide (H2S) produced from factory exhaust because it is a toxic gas that poses a serious threat to human health and the environment. Here are some methods to treat hydrogen sulfide produced from factory exhaust:

 

It is important to treat hydrogen sulfide (H2S) produced from factory exhaust because it is a toxic gas that poses a serious threat to human health and the environment. Here are some methods to treat hydrogen sulfide produced from factory exhaust:

1.Adsorption:

Hydrogen sulfide can be adsorbed from the gas using adsorbent materials such as activated carbon, iron oxide, zinc oxide, etc. These materials have high adsorption capacity and can effectively remove hydrogen sulfide.

2. Chemical oxidation:

Hydrogen sulfide can be oxidized into more stable and easy-to-handle products such as sulfate using chemical oxidants such as hydrogen peroxide (H2O2) and potassium permanganate (KMnO4).

3. Biological treatment:

Hydrogen sulfide can be oxidized into sulfate or sulfur using sulfur-oxidizing bacteria, thereby reducing its toxicity. This can be achieved through methods such as biofilters and bioreactors.

4. Catalytic oxidation:

The use of catalysts such as iron oxide, zinc oxide, etc. can promote the oxidation reaction of hydrogen sulfide and convert it into sulfate.

5. Dry absorption method:

One of the commonly used methods in industry, by passing hydrogen sulfide into a bed containing an oxidant or absorbent, it is converted into an easy-to-handle product.  

6. Wet absorption method:

Use alkaline solutions such as sodium hydroxide (calcium hydroxide) and ammonia water for wet absorption to absorb hydrogen sulfide and convert it into sulfide.

7. Desorption method:

By regenerating the adsorbent under high temperature conditions, the hydrogen sulfide adsorbed on the adsorbent is released and then treated.

8. Incineration:

The waste gas containing hydrogen sulfide is incinerated at high temperature to oxidize it into substances such as sulfur dioxide (SO2).   Different factories and waste gas characteristics may require different treatment methods. The selection of appropriate treatment technology requires consideration of factors such as waste gas composition, concentration, volume and environmental regulations. When treating waste gas, please be sure to follow local environmental regulations to ensure that waste gas emissions meet safety standards.  

Desulfurized activated carbon is a kind of sulfur-containing material with a black, odorless, non-toxic appearance and a developed internal pore structure. It is a kind of microcrystalline carbon material with large specific surface area and strong adsorption capacity, and is a commonly used adsorbent.  

Desulfurized activated carbon refers to the use of activated carbon to load sulfonated titanium cyanocobalt to remove excessive mercaptans in crude oil during the gasoline refining process, thereby reducing the sulfur content of gasoline and improving the quality. It meets the requirements of national environmental protection emissions.  

Desulfurized activated carbon is processed by adding more than a dozen promoters. It is a gas catalyst with a developed microporous structure, which can remove hydrogen sulfide and some organic sulfur in the gas.  

Desulfurized activated carbon is widely used in various gas sources such as biogas and liquefied gas for the removal of hydrogen sulfide and some organic sulfur. It has the characteristics of easy operation, high purification, low bed resistance, strong adaptability, fast desulfurization of hydrogen sulfide and some organic sulfur, and high capacity. It is a new type of high-efficiency gas catalyst that can maintain high activity and capacity at normal temperature and pressure.

Biogas is a renewable clean energy source produced by the decomposition of organic matter under anaerobic conditions. However, biogas usually contains a certain amount of hydrogen sulfide (H2S), which is highly corrosive and will not only damage biogas equipment but also have an impact on the environment and human health. Therefore, before using biogas, desulfurization treatment is required. Biogas desulfurizers are chemicals used to remove hydrogen sulfide from biogas. Their composition and working principle vary depending on the type of desulfurizer.  

Precautions for using activated carbon desulfurization:  

1. The desulfurization effect of activated carbon is better in the temperature range of 5~60℃. When the temperature is greater than 60℃, the adsorption capacity of the activated carbon surface for sulfides becomes weaker, and the desulfurization efficiency decreases. The desulfurization effect of activated carbon desulfurization is poor in dry gas, and the relative purity of the purified gas is required to be between 70% and 100%. If necessary, water should be appropriately added. Since the activated carbon fine desulfurizer has been added with active components that can greatly accelerate the desulfurization reaction during the preparation process, it is no longer necessary to add ammonia to the raw materials when using it like the activated carbon crude desulfurizer;  

The process of activated carbon fine desulfurization at room temperature is completed by combining a special type of activated carbon desulfurizer with E2X fine desulfurizer. This process can achieve fine desulfurization at room temperature, or the temperature range is maintained between 10~60℃, and CS2 can be removed at the same time. Since the fine desulfurization capacity of EZX desulfurizer for COS and CS2 is relatively low, at 2%~3%, this process is generally suitable for process gases with low organic sulfur content. It can remove the total sulfur content of H2S, COS, and CS2 to 0.1ml/m³.

Biogas desulfurization:

In the context of energy resource shortage, biogas, as a renewable energy source, is increasingly valued. Usually, the main components of biogas are methane (60~70%) and carbon dioxide (30~40%), as well as a small amount of hydrogen sulfide and other gases. Hydrogen sulfide, as a highly toxic and harmful gas, has a strong corrosive effect on pipelines, burners, instruments, etc. After combustion, hydrogen sulfide generates sulfur dioxide, which pollutes the environment and affects human health. my country's environmental protection standards strictly stipulate that when using biogas energy, the hydrogen sulfide content in biogas gas shall not exceed 20mg/m³. The mass concentration of hydrogen sulfide in biogas is generally 1~12g/m³, which is much higher than the provisions of my country's environmental protection standards. Therefore, the removal of hydrogen sulfide becomes an essential link in the process of biogas utilization.

The basic principle of removing hydrogen sulfide from biogas is to use oxygen and hydrogen sulfide to oxidize sulfur or sulfur oxides, which is also called dry oxidation. The dry equipment consists of a container with a packing layer containing activated carbon, iron oxide, etc. The gas passes through the packing layer in the container at a low flow rate from one end. After the hydrogen sulfide is oxidized into sulfur or oxides, it remains in the packing layer. The purified gas is discharged from the other end of the container. It has a huge specific surface area and can effectively remove color and odor. When hydrogen sulfide passes through activated carbon and iron oxide, it reacts to generate sulfide and separate it from biogas. Because the surface area of ​​activated carbon is large, it can fully contact with gas (impurities). The strong adsorption force given by the developed pore structure of activated carbon itself can fully adsorb these gases (impurities).