沼氣凈化的主要目的是去除二氧化碳,得到高純度的甲烷。沼氣凈化技術(shù)主要來源于天然氣、合成氨轉(zhuǎn)化氣脫碳技術(shù)。由于沼氣的用量遠(yuǎn)遠(yuǎn)小于天然氣或合成氨轉(zhuǎn)化氣,因此在選擇脫碳技術(shù)時(shí)應(yīng)注重小型化和節(jié)能。目前,沼氣凈化技術(shù)大致可分為:吸附、吸附、膜分離、低溫凈化。
The main purpose of biogas purification is to remove carbon dioxide and get high purity methane. Biogas purification technology mainly comes from decarbonization technology of natural gas and synthetic ammonia conversion gas. Since the consumption of biogas is far less than that of natural gas or ammonia conversion gas, we should pay attention to miniaturization and energy saving when choosing decarbonization technology. At present, biogas purification technology can be roughly divided into adsorption, adsorption, membrane separation and low-temperature purification.
廣泛應(yīng)用的沼氣凈化技術(shù)主要有:變壓吸附、水洗、有機(jī)溶劑物理吸附、有機(jī)溶劑化學(xué)吸附、高壓膜分離、低溫凈化等。下表為六種沼氣凈化技術(shù)的關(guān)鍵參數(shù)。
The widely used biogas purification technologies include pressure swing adsorption, water washing, organic solvent physical adsorption, organic solvent chemical adsorption, high-pressure membrane separation, low-temperature purification, etc. The following table shows the key parameters of six biogas purification technologies.
在瑞典,壓力清洗是常用的;在德國,psa更為普遍。在荷蘭,壓力清洗、變壓吸附和膜分離都得到了廣泛的應(yīng)用。下表是五種沼氣凈化技術(shù)的經(jīng)濟(jì)比較。
In Sweden, pressure cleaning is the most common; in Germany, PSA is more common. In the Netherlands, pressure cleaning, PSA and membrane separation have been widely used. The following table shows the economic comparison of five biogas purification technologies.
注:電力消耗成本(12 ~ 18歐元美分/千瓦時(shí)),熱耗成本(3 ~ 5歐分/千瓦時(shí)),水的成本是5歐元/ m?(包括污水處理費(fèi)用)。沒有考慮進(jìn)一步的處理費(fèi)用(如分離硅氧烷或氨)。所有值都基于滿負(fù)荷運(yùn)行。
Note: the cost of electricity consumption (12-18 euro cents / kWh), heat consumption (3-5 euro cents / kWh), and water is 5 euro / M 3 (including the cost of sewage treatment). No further treatment costs (such as separation of siloxane or ammonia) were considered. All values are based on full load operation.
沼氣凈化成本與原料氣甲烷含量和成品甲烷含量有關(guān)。未經(jīng)處理的沼氣,甲烷含量高,凈化成本低。這主要是由于能源產(chǎn)量的增加,總成本與更高的能源水平相關(guān)??梢酝ㄟ^提高效率(降低單位產(chǎn)出的能耗)和使用高熱值的原沼氣來降低實(shí)際能耗來降低成本。
The cost of biogas purification is related to the methane content of feed gas and finished product. Untreated biogas has high methane content and low purification cost. This is mainly due to the increase in energy production, with total costs associated with higher energy levels. The cost can be reduced by improving efficiency (reducing energy consumption per unit output) and using high calorific value biogas to reduce the actual energy consumption.
沼氣凈化站的經(jīng)濟(jì)性還與其他因素有關(guān),如可操作性和額定負(fù)荷。沼氣凈化站的額定運(yùn)行負(fù)荷不僅取決于凈化站本身的高穩(wěn)定性,還取決于原沼氣流及后續(xù)裝置(如充電站、加氣站)的可靠性。
The economy of biogas purification station is also related to other factors, such as operability and rated load. The rated operation load of the biogas purification station not only depends on the high stability of the purification station itself, but also depends on the reliability of the original biogas flow and subsequent devices (such as charging station and gas filling station).
短停機(jī)時(shí)間,設(shè)備運(yùn)行良好,在額定負(fù)載和充足的原料氣條件下設(shè)備能正常連續(xù)運(yùn)行,是沼氣凈化站高效可用的標(biāo)準(zhǔn)??焖夙憫?yīng)時(shí)間至關(guān)重要,因此技術(shù)供應(yīng)商提供良好的網(wǎng)絡(luò)服務(wù)至關(guān)重要。此外,還可以使用遠(yuǎn)程監(jiān)控,操作被中斷時(shí),技術(shù)人員可以直接找到故障,根據(jù)故障類型立即采取必要的補(bǔ)救措施,避免時(shí)間延遲,不需要長途旅行的服務(wù)技術(shù)人員到現(xiàn)場解決問題。
Short shutdown time, good operation of the equipment, normal and continuous operation of the equipment under rated load and sufficient feed gas conditions, is the standard of high efficiency and availability of biogas purification station. Fast response time is very important, so it is very important for technology providers to provide good network services. In addition, remote monitoring can also be used. When the operation is interrupted, the technical personnel can find the fault directly. According to the fault type, necessary remedial measures can be taken immediately to avoid time delay. The service technical personnel who do not need long-distance travel can go to the site to solve the problem.
這些co2 /甲烷分離方法已經(jīng)在其他行業(yè)使用了幾十年,是的沼氣凈化方法。近年來發(fā)展趨勢是減少能源消耗,提高回收率,降低甲烷的排放,主要有以下措施:減少成品氣體壓力降低功耗,降低解吸過程的溫度水平(胺),二氧化碳/甲烷發(fā)展高選擇性,促進(jìn)生物甲烷液化技術(shù)和綜合處理技術(shù)(如膜和低溫分離)。
These CO2 / methane separation methods have been used in other industries for decades and are the most advanced methane purification methods. In recent years, the development trend is to reduce the energy consumption, improve the recovery rate and reduce the emission of methane, mainly including the following measures: reduce the pressure of finished gas, reduce the power consumption, reduce the temperature level (amine) of desorption process, develop high selectivity of carbon dioxide / methane, and promote the liquefaction technology and comprehensive treatment technology of biomethane (such as membrane and low-temperature separation).