隨著減排政策的日益普及,沼氣提純符合減排的大趨勢(shì)。許多企業(yè)打算使用污水處理站的沼氣部分代替天然氣,然后進(jìn)入鍋爐進(jìn)行燃燒或發(fā)電。然后,沼氣利用之前的硫化氫去除過(guò)程(脫硫)成為工廠和電站所有者的選擇難題。目前,常用的工藝有干法脫硫,濕法脫硫和生物脫硫。
With the increasing popularity of energy conservation and emission reduction policies, biogas purification is in line with the general trend of energy conservation and emission reduction. Many enterprises plan to use biogas from sewage treatment stations to replace natural gas, and then enter boilers for combustion or power generation. Then, the hydrogen sulfide removal process (desulfurization) before biogas utilization becomes a difficult choice for plant and power plant owners. At present, the commonly used processes are dry desulfurization, wet desulfurization and biological desulfurization.
1.干法脫硫
1. Dry desulfurization
干法,濕法和生物脫硫工藝的比較
Comparison of dry, wet and biological desulfurization processes
沼氣經(jīng)過(guò)填料層(主要由活性炭和氧化鐵組成)凈化后,從脫硫塔的一端流向另一端。硫化氫與填料層中的氧化鐵反應(yīng)形成硫化鐵,硫化鐵可以在反應(yīng)后再生。
After being purified by packing layer (mainly composed of activated carbon and iron oxide), biogas flows from one end of desulfurization tower to the other. Hydrogen sulfide reacts with iron oxide in the packing layer to form iron sulfide, which can be regenerated after reaction.
2.濕法脫硫
2. Wet desulfurization
沼氣提純和濕法脫硫是將沼氣送入洗滌塔。洗滌并被堿性溶液吸收后,洗滌液將流入富液槽和再生槽中。通過(guò)化學(xué)方法,將醉嘴轉(zhuǎn)變?yōu)閱钨|(zhì)硫(泡沫泡沫),吸收液可以回收利用。
Biogas purification and wet desulfurization is to send biogas into washing tower. After washing and being absorbed by alkaline solution, the washing solution will flow into rich solution tank and regeneration tank. Through chemical method, the intoxicated mouth is changed into elemental sulfur (foam foam), and the absorption liquid can be recycled.
3.生物脫硫
3. Biological desulfurization
生物脫硫也是濕式脫硫的一種。與上述濕法脫硫的催化氧化過(guò)程相比,區(qū)別在于使用硫桿菌屬代替化學(xué)催化劑將硫化物直接氧化成硫。
Biological desulfurization is also a kind of wet desulfurization. Compared with the catalytic oxidation process of wet desulfurization, the difference is that Thiobacillus is used instead of chemical catalyst to directly oxidize sulfide to sulfur.
說(shuō)明:
explain:
1)干法脫硫通常在負(fù)荷較小或?qū)γ摿蛐Ч筝^高的情況下使用。此時(shí),在濕式脫硫或生物脫硫后,通常將干式脫硫用于進(jìn)一步的脫硫。
1) Dry desulfurization is usually used under the condition of low load or high demand for desulfurization effect. In this case, after wet desulfurization or biological desulfurization, dry desulfurization is usually used for further desulfurization.
2)在制定脫硫效果時(shí),建議根據(jù)后續(xù)設(shè)備(鍋爐或發(fā)電機(jī))對(duì)硫化氫濃度以及沼氣和天然氣消耗比例的限制,制定合理的脫硫效果。我們通常建議將硫化氫含量控制在25-100ppm。
2) It is suggested to formulate reasonable desulfurization effect according to the limitation of hydrogen sulfide concentration and consumption ratio of biogas and natural gas by follow-up equipment (boiler or generator). We usually recommend that the hydrogen sulfide content be controlled at 25-100ppm.
沼氣提純脫水方法:
Purification and dehydration method of biogas:
來(lái)自發(fā)酵廠的沼氣包含飽和水蒸氣,可以通過(guò)三種方法將其除去。
Biogas from the fermentation plant contains saturated water vapor, which can be removed in three ways.
(1)冷分離法。
(1) Cold separation method.
冷分離法是利用壓力能的變化引起溫度的變化并使水蒸氣從氣相中冷凝的方法。
The cold separation method is a method which uses the change of pressure energy to cause the change of temperature and condense the water vapor from the gas phase.
(2)溶劑吸收法。脫水溶劑是氯化鈣,氯化鋰和乙二醇。
(2) Solvent absorption method. The dehydration solvent is calcium chloride, lithium chloride and ethylene glycol.
(3)固體物理吸水法。在固體表面力的作用下產(chǎn)生吸附。根據(jù)表面力的性質(zhì),可分為化學(xué)吸附和物理吸附(脫水后再生)。
(3) Solid physical water absorption method. Adsorption occurs under the action of solid surface force. According to the nature of surface force, it can be divided into chemical adsorption and physical adsorption (regeneration after dehydration).