隨著節(jié)能減排政策不斷深入人心，很多企業(yè)都打算利用污水站的沼氣部分代替天然氣，進入鍋爐燃燒或發(fā)電。那么，沼氣利用前的硫化氫脫除工藝(脫硫)，就成為工廠和站長們的選擇難點。當(dāng)前，比較常用的工藝有唐山綠源干法脫硫、濕法脫硫和生物脫硫，本文就將三種工藝為您做一個簡單的說明和對比。

With the deepening of energy-saving and emission reduction policies, many enterprises plan to use the biogas from sewage treatment plants to replace natural gas and enter boilers for combustion or power generation. So, the hydrogen sulfide removal process (desulfurization) before biogas utilization has become a difficult choice for factories and station managers. Currently, the commonly used processes include Tangshan Green Source Dry Desulfurization, Wet Desulfurization, and Biological Desulfurization. This article will provide a brief explanation and comparison of the three processes for you.

一、常見的脫硫工藝

1、 Common desulfurization processes

1. 干法脫硫

1. Dry desulfurization

干法、濕法和生物脫硫三大工藝比較

Comparison of Three Major Processes of Dry, Wet, and Biological Desulfurization

沼氣從脫硫塔的一端，經(jīng)過填料層(主要成分是活性炭和氧化鐵)凈化后，從另一端流出。硫化氫與填料層的氧化鐵發(fā)生反應(yīng)，生成硫化鐵;待氧化鐵反應(yīng)結(jié)束后，可進行再生。

Biogas is purified from one end of the desulfurization tower through a packing layer (mainly composed of activated carbon and iron oxide) before flowing out from the other end. Hydrogen sulfide reacts with iron oxide in the filler layer to generate iron sulfide; After the iron oxide reaction is completed, regeneration can be carried out.

脫硫原理：

Desulfurization principle:

Fe2O3 ˙ H2O+ 3H2S = Fe2S3 + 4 H2O

Fe2O3 ˙  H2O+3H2S=Fe2S3+4 H2O

再生原理：

Regeneration principle:

Fe2S3 + 3/2 O2+ 3 H2O = Fe2O3 ˙H2O + 2 H2O+ 3 S

Fe2S3+3/2 O2+3 H2O=Fe2O3 ˙ H2O+2 H2O+3 S

2. 濕法脫硫

2. Wet desulfurization

濕法脫硫是將沼氣送入洗滌塔，經(jīng)堿性溶液洗滌吸收后流出，洗滌液進入富液槽、再生槽，通過使用化學(xué)藥劑方法催化、氧化，zui終將硫化物轉(zhuǎn)化為單質(zhì)硫(硫泡沫)，吸收液可以再生循環(huán)使用。

Wet desulfurization is to send biogas into the scrubber, wash and absorb it with alkaline solution, and then flow out. The washing solution enters the rich solution tank and regeneration tank. Through catalysis and oxidation with chemical agents, zui will eventually convert sulfide into elemental sulfur (sulfur foam), and the absorption solution can be recycled for use.

3. 生物脫硫

3. Biological desulfurization

生物脫硫也是濕法脫硫的一種，與上述濕法脫硫的催化氧化工藝相比，zui大區(qū)別是使用硫桿菌替代化學(xué)催化劑，將硫化物直接氧化成硫單質(zhì)。

Biological desulfurization is also a type of wet flue gas desulfurization. Compared with the catalytic oxidation process of wet flue gas desulfurization mentioned above, the main difference is the use of sulfur bacteria instead of chemical catalysts to directly oxidize sulfides into elemental sulfur.

反應(yīng)原理：

Reaction principle:

H2S + OH-= HS- + H2O

H2S+OH -=HS -+H2O

HS- + 1/2O2= So + OH-

HS -+1/2O2=So+OH-

說明：

Explanation:

1) 干法脫硫多用于硫化氫處理負荷小，或者對脫硫效果要求很高的工況。這時，干法脫硫多用于濕法脫硫或者生物脫硫之后，進一步脫硫。

1) Dry desulfurization is commonly used in hydrogen sulfide treatment with low load or high requirements for desulfurization efficiency. At this time, dry desulfurization is often used for further desulfurization after wet desulfurization or biological desulfurization.

2)在制定脫硫效果時，建議根據(jù)后續(xù)設(shè)備(鍋爐或發(fā)電機)對硫化氫濃度的限制，以及沼氣與天然氣消耗量的比例，制定一個合理的脫除效果。我們通常建議zui終的硫化氫含量控制在25~100ppm。

2) When formulating the desulfurization effect, it is recommended to develop a reasonable removal effect based on the limitations of subsequent equipment (boilers or generators) on hydrogen sulfide concentration, as well as the ratio of biogas to natural gas consumption. We usually recommend controlling the final hydrogen sulfide content between 25-100ppm.

沼氣脫水的方法

The method of biogas dehydration

從發(fā)酵裝置出來的沼氣含有飽和水蒸氣，可用3種方法將其去除。

The biogas produced from the fermentation device contains saturated water vapor, which can be removed using three methods.

(1)冷分離法。

(1) Cold separation method.

冷分離法是利用壓力能變化引起溫度變化，使水蒸氣從氣相中冷凝下來的方法。常用的有兩種流程：A．節(jié)流膨脹冷脫水法。一般用于高壓燃氣，經(jīng)過節(jié)流膨脹或低溫分離，使部分水冷凝下來。B．加壓后冷卻法。如凈化氣在0.8MPa壓力下的冷卻脫水.

Cold separation method is a method of using pressure energy changes to cause temperature changes and condense water vapor from the gas phase. There are two commonly used processes: A. throttling expansion cold dehydration method. Generally used for high-pressure gas, it undergoes throttling expansion or low-temperature separation to condense some water. B. Pressure followed cooling method. Cooling and dehydration of purified gas at a pressure of 0.8 MPa

(2)溶劑吸收法。屬于這類脫水溶劑的有氯化鈣、氯化鋰及甘醇類。

(2) Solvent absorption method. Calcium chloride, lithium chloride, and ethylene glycol belong to this type of dehydration solvent.

(3)固體物理吸水法。吸附是在固體表面力作用下產(chǎn)生的，根據(jù)表面力的性質(zhì)分為化學(xué)吸附脫水后不能再生)和物理吸附(脫水后可再生)

(3) Solid state physical water absorption method. Adsorption is generated under the action of solid surface forces, and is divided into chemical adsorption (which cannot be regenerated after dehydration) and physical adsorption (which can be regenerated after dehydration) based on the properties of surface forces