沸石轉(zhuǎn)輪中VOCs殘留的處理
國內(nèi)外對VOC的末端治理方法有:冷凝、吸附、氧化、生物處理、吸收、等離子體凈化等。以沸石材料為載體的吸附濃縮法處理VOC廢氣(沸石轉(zhuǎn)輪)得到了較為廣泛的應(yīng)用。全國對VOCs污染物防治的要求和力度逐漸加強,低濃度廢氣治理的沸石轉(zhuǎn)輪吸附濃縮法成為了很多企業(yè)的優(yōu)選治理方案。
The end treatment methods for VOC at home and abroad include condensation, adsorption, oxidation, biological treatment, absorption, plasma purification, etc. The adsorption concentration method using zeolite materials as carriers has been widely used in the treatment of VOC waste gas (zeolite wheels). The national requirements and efforts for the prevention and control of VOCs pollutants are gradually strengthening, and the zeolite rotary adsorption concentration method for low concentration waste gas treatment has become the preferred treatment plan for many enterprises.
在使用的過程中,因為VOCs在轉(zhuǎn)輪內(nèi)部的殘留,會導(dǎo)致沸石轉(zhuǎn)輪劣化,處理效率降低,要如何避免和應(yīng)對這樣的情況呢?
During use, the residue of VOCs inside the impeller can lead to the deterioration of the zeolite impeller and a decrease in treatment efficiency. How can we avoid and respond to such situations?
降低沸石轉(zhuǎn)輪設(shè)備內(nèi)部VOCs殘留主要從改善VOCs廢氣的進(jìn)氣質(zhì)量和加強脫附效率兩方面入手。
Reducing the residual VOCs inside the zeolite rotary equipment mainly starts from improving the intake quality of VOCs waste gas and strengthening the desorption efficiency.
01.廢氣預(yù)處理
01. Waste gas pretreatment
廢氣預(yù)處理措施通常有除塵、除濕、除霧、除高沸物等。針對要處理的VOCs廢氣實際情況,需選取適當(dāng)?shù)膹U氣預(yù)處理措施。比如,半導(dǎo)體生產(chǎn)制造過程對生產(chǎn)場所的顆粒物有嚴(yán)格的要求,生產(chǎn)場所通常為潔凈車間。因此,有機廢氣中的顆粒物含量極少,通常無需進(jìn)行除塵預(yù)處理。
The pre-treatment measures for exhaust gas usually include dust removal, dehumidification, defogging, and removal of high boiling substances. According to the actual situation of VOCs waste gas to be treated, appropriate waste gas pretreatment measures need to be selected. For example, the semiconductor manufacturing process has strict requirements for particulate matter in the production site, which is usually a clean workshop. Therefore, the particulate matter content in organic waste gas is extremely low and usually does not require dust removal pretreatment.
比如,芯片制造業(yè)生產(chǎn)過程中使用的主要有機原料通常具有低沸點、易揮發(fā)的特點,但仍不排除少量高沸點物質(zhì),如剝離液的主要成分二甘醇胺(沸程218~224℃)等??稍诟叻悬c物質(zhì)的處理工序中增設(shè)冷凝、前道活性炭吸附等預(yù)處理裝置,以避免VOCs廢氣中難脫附的高沸點物質(zhì)進(jìn)入沸石轉(zhuǎn)輪。
For example, the main organic raw materials used in the production process of chip manufacturing usually have the characteristics of low boiling point and easy volatility, but a small amount of high boiling point substances cannot be ruled out, such as the main component of the stripping solution, diethylene glycol amine (boiling range 218-224 ℃). Pre treatment devices such as condensation and front activated carbon adsorption can be added in the treatment process of high boiling point substances to prevent high boiling point substances that are difficult to desorb from VOCs waste gas from entering the zeolite runner.
高沸點VOCs進(jìn)入廢氣管道后容易凝結(jié),從而使廢氣濕度增大。當(dāng)進(jìn)入沸石轉(zhuǎn)輪系統(tǒng)的有機廢氣濕度大于80%時,將對疏水性沸石分子篩產(chǎn)生較為嚴(yán)重的影響。因此,建議對高濕度廢氣增設(shè)干燥除濕預(yù)處理裝置,使得進(jìn)入廢水轉(zhuǎn)輪系統(tǒng)的廢氣濕度保持在穩(wěn)定、可控的范圍內(nèi)。
High boiling point VOCs are prone to condensation after entering the exhaust gas pipeline, thereby increasing the humidity of the exhaust gas. When the humidity of the organic waste gas entering the zeolite rotary system exceeds 80%, it will have a serious impact on the hydrophobic zeolite molecular sieve. Therefore, it is recommended to install a drying and dehumidification pre-treatment device for high humidity exhaust gas, so as to maintain the humidity of the exhaust gas entering the wastewater rotary system within a stable and controllable range.
02.高溫再生
02. High temperature regeneration
根據(jù)對國內(nèi)芯片企業(yè)開展的調(diào)研可知,芯片制造業(yè)常用的有機物質(zhì)有異丙醇(沸點為82.45℃)、丙二醇單甲醚乙酸酯(沸點為146℃);同時還含有少量的高沸點物質(zhì),例如二甘醇胺(沸程218~224℃)。
According to research conducted on domestic chip companies, the commonly used organic substances in the chip manufacturing industry include isopropanol (boiling point of 82.45 ℃) and propylene glycol monomethyl ether acetate (boiling point of 146 ℃); It also contains a small amount of high boiling substances, such as diethylene glycol amine (boiling range 218-224 ℃).
通常芯片制造業(yè)沸石轉(zhuǎn)輪的再生溫度為180-200℃,在此再生溫度下,高沸點的二甘醇胺等物質(zhì)將無法從沸石轉(zhuǎn)輪上有效脫附,從而逐漸積聚在轉(zhuǎn)輪內(nèi)部。
The regeneration temperature of zeolite wheels in the chip manufacturing industry is usually 180-200 ℃. At this regeneration temperature, high boiling substances such as diethylene glycol amine cannot be effectively desorbed from the zeolite wheels, gradually accumulating inside the wheels.
經(jīng)過對沸石轉(zhuǎn)輪系統(tǒng)的高沸點物質(zhì)聚集情況開展的研究,可知當(dāng)沸石轉(zhuǎn)輪系統(tǒng)運行1個月后,轉(zhuǎn)輪內(nèi)部確實有較大量的有機物積聚,其有機物積聚量即達(dá)6wt%。進(jìn)行有效的高溫脫附之后,其內(nèi)部的有機物積聚量可降低約40%~60%。因此,高溫脫附可較為有效地去除沸石轉(zhuǎn)輪內(nèi)部積聚的高沸點有機物質(zhì)。
After conducting research on the aggregation of high boiling substances in the zeolite rotary system, it is known that after one month of operation, there is indeed a large amount of organic matter accumulation inside the rotary system, with an organic matter accumulation amount of 6wt%. After effective high-temperature desorption, the accumulation of organic matter inside can be reduced by about 40% to 60%. Therefore, high-temperature desorption can effectively remove high boiling organic matter accumulated inside the zeolite impeller.
企業(yè)應(yīng)根據(jù)廢氣的實際產(chǎn)生情況,分析廢氣組成分布,分析高沸點物質(zhì)占比情況,以及廢氣的產(chǎn)生總量等內(nèi)容,從而確定高溫再生頻次。較為適宜的高溫再生頻次為2~3個月一次。
Enterprises should analyze the distribution of exhaust gas composition, the proportion of high boiling substances, and the total amount of exhaust gas generated based on the actual generation of exhaust gas, in order to determine the frequency of high-temperature regeneration. The more suitable frequency for high-temperature regeneration is once every 2-3 months.
高溫再生的溫度也會影響高溫脫附效果。若高溫脫附溫度選取過低,則高沸點物質(zhì)仍無法有效脫除;若高溫脫附溫度選取過高,將對沸石分子篩的骨架結(jié)構(gòu)產(chǎn)生一定的影響,從而降低其使用壽命。高溫脫附溫度宜選取300℃左右,并且,相應(yīng)的沸石轉(zhuǎn)輪內(nèi)部配件均需采用可耐300℃高溫的密封配件。
The temperature of high-temperature regeneration can also affect the high-temperature desorption effect. If the high-temperature desorption temperature is selected too low, the high boiling point substance cannot be effectively removed; If the high temperature desorption temperature is selected too high, it will have a certain impact on the skeleton structure of zeolite molecular sieve, thereby reducing its service life. The high-temperature desorption temperature should be around 300 ℃, and the corresponding internal components of the zeolite impeller should use sealing components that can withstand high temperatures of 300 ℃.
03.水洗再生
03. Water washing regeneration
芯片制造業(yè)常用的有機物質(zhì)(如異丙醇、丙二醇單甲醚乙酸酯等)通常具有較好的水溶性,可采用水洗再生的方式去除沸石轉(zhuǎn)輪內(nèi)部聚集的高沸點物質(zhì)。
Organic substances commonly used in the chip manufacturing industry, such as isopropanol, propylene glycol monomethyl ether acetate, etc., usually have good water solubility and can be removed by water washing regeneration to remove high boiling substances accumulated inside the zeolite impeller.
水洗再生可有效提高沸石轉(zhuǎn)輪系統(tǒng)的治理效率,對于工廠,當(dāng)水洗再生次數(shù)達(dá)到4~6次/年時,沸石轉(zhuǎn)輪系統(tǒng)的治理效率可達(dá)95%~99%。因此,適當(dāng)增加定期水洗再生頻次,可有效防止高沸點物質(zhì)在沸石轉(zhuǎn)輪內(nèi)部的聚集,保持高治理效率。
Water washing regeneration can effectively improve the treatment efficiency of zeolite rotary system. For factories, when the water washing regeneration frequency reaches 4-6 times per year, the treatment efficiency of zeolite rotary system can reach 95% to 99%. Therefore, increasing the frequency of regular water washing regeneration can effectively prevent the aggregation of high boiling substances inside the zeolite impeller and maintain high treatment efficiency.
由于沸石轉(zhuǎn)輪通常采用無機粘合劑將分子篩涂覆在陶瓷纖維紙表面制造而成,故水洗時不僅轉(zhuǎn)輪不會發(fā)生龜裂形變,也不會發(fā)生由于分子篩脫落所導(dǎo)致的性能劣化、使用壽命縮短等問題。
Due to the fact that zeolite wheels are usually manufactured by coating molecular sieves on the surface of ceramic fiber paper using inorganic adhesives, not only will the wheels not undergo cracking deformation during water washing, but also there will be no problems such as performance degradation and shortened service life caused by molecular sieve detachment.
但是,水洗時需要注意水質(zhì)狀況,若其中大量含有鈣、鎂等離子,將可能在沸石內(nèi)部形成碳酸鹽,阻塞沸石轉(zhuǎn)輪的蜂窩狀孔道;水中所含微量重金屬物質(zhì)、氯等也會毒化沸石。
However, attention should be paid to the water quality during washing. If a large amount of calcium and magnesium ions are present, carbonates may form inside the zeolite, blocking the honeycomb like channels of the zeolite impeller; Trace amounts of heavy metals and chlorine in water can also poison zeolite.
值得注意的是,并非所有沸石轉(zhuǎn)輪材質(zhì)均耐水洗,企業(yè)應(yīng)在水洗再生之前,向沸石轉(zhuǎn)輪設(shè)備的制造廠商做好相關(guān)的咨詢工作。
It is worth noting that not all zeolite wheel materials are resistant to water washing. Enterprises should consult with the manufacturer of zeolite wheel equipment before water washing and regeneration.
04.高壓空氣吹掃
04. High pressure air blowing
企業(yè)在停機檢維修期間,采用高壓空氣對沸石轉(zhuǎn)輪進(jìn)行吹掃。然而,高壓空氣吹掃通常只可清除沸石轉(zhuǎn)輪表面附著的灰塵,而VOCs有機質(zhì)通常吸附在分子篩孔道內(nèi)部,無法得到有效的脫除,還需與上述其他處理方式配合選用。
During the shutdown inspection and maintenance period, the enterprise uses high-pressure air to blow and sweep the zeolite wheel. However, high-pressure air blowing usually only removes the dust attached to the surface of the zeolite impeller, while VOCs organic matter is usually adsorbed inside the molecular sieve pores and cannot be effectively removed. Therefore, it is necessary to choose in combination with other treatment methods mentioned above.
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