沸石轉(zhuǎn)輪主要將大風(fēng)量、低濃度的廢氣濃縮到高濃度、小風(fēng)量的廢氣，從而減少設(shè)備的投入費(fèi)用和運(yùn)行成本，提高VOCs廢氣的處理效率。利用熱氧化技術(shù)在處理大風(fēng)量、低濃度的廢氣的時(shí)候，如果沒有沸石轉(zhuǎn)輪直接進(jìn)行燃燒，廢氣處理設(shè)備不僅體積龐大，而且產(chǎn)生的運(yùn)行費(fèi)用也很高昂。那么沸石轉(zhuǎn)輪在處理VOCs時(shí)有哪些注意事項(xiàng)呢？

The zeolite wheel mainly concentrates high air volume and low concentration waste gas to high concentration and low air volume waste gas, thereby reducing equipment investment and operating costs, and improving the treatment efficiency of VOCs waste gas. When using thermal oxidation technology to treat high air volume and low concentration waste gas, if there is no zeolite wheel for direct combustion, the waste gas treatment equipment not only has a large volume, but also incurs high operating costs. So what are the precautions for zeolite wheels when dealing with VOCs?

1廢氣成分

1. Composition of exhaust gas

沸石是一種混合物，其成分不同，能夠吸附的VOCs組分也有所差異。因此，在選擇轉(zhuǎn)輪時(shí)，需明確廢氣的主要成分、含量、濃度、風(fēng)量等參數(shù)，以便選擇更加合適的沸石材料，達(dá)到有效吸附VOCs的目的。

Zeolite is a mixture with different components, and the components of VOCs that can be adsorbed also vary. Therefore, when selecting the impeller, it is necessary to clarify the main components, content, concentration, air volume and other parameters of the exhaust gas in order to select more suitable zeolite materials and achieve the effective adsorption of VOCs.

廢氣成分比較單一或者成分特性比較接近時(shí)，選用一級(jí)轉(zhuǎn)輪就能夠達(dá)到目的。但是，如果廢氣成分比較復(fù)雜，一級(jí)轉(zhuǎn)輪不能一次性處理的話，可以考慮使用兩級(jí)轉(zhuǎn)輪來處理，兩級(jí)轉(zhuǎn)輪可針對(duì)不同組分進(jìn)行處理，能有效提高處理效率。

When the composition of exhaust gas is relatively single or the composition characteristics are similar, selecting a first stage impeller can achieve the goal. However, if the composition of the exhaust gas is complex and the first stage impeller cannot be used for one-time treatment, it can be considered to use a two-stage impeller for treatment. The two-stage impeller can be used to treat different components, which can effectively improve treatment efficiency.

當(dāng)廢氣中含有沸點(diǎn)高的VOCs時(shí)，如果脫附熱量不足吸附劑沒有完全脫附，會(huì)使吸附劑在吸附區(qū)堆積。隨著時(shí)間的推移，會(huì)發(fā)生聚合反應(yīng)，進(jìn)而堵塞沸石的吸附位置，導(dǎo)致這一區(qū)域的吸附效率降低。

When the exhaust gas contains VOCs with high boiling points, if the desorption heat is insufficient and the adsorbent is not completely desorbed, it will cause the adsorbent to accumulate in the adsorption zone. Over time, polymerization reactions will occur, leading to blockage of the adsorption site of zeolite and a decrease in adsorption efficiency in this area.

為了使吸附在沸石中的高沸點(diǎn)VOCs完全脫附，避免造成高沸點(diǎn)VOCs的解吸困難，在進(jìn)入吸附輪前要用濾布或活性炭對(duì)廢氣進(jìn)行過濾，添加除霧器或冷凝器，先將高沸點(diǎn)VOCs去除。

In order to completely desorb high boiling VOCs adsorbed in zeolite and avoid difficulties in desorbing high boiling VOCs, filter the exhaust gas with filter cloth or activated carbon before entering the adsorption wheel, add a defogger or condenser, and first remove the high boiling VOCs.

2廢氣冷卻

2. Exhaust gas cooling

沸石的特性是在溫度較低時(shí)具有很強(qiáng)的吸附性能，溫度較高時(shí)呈現(xiàn)脫附性能。因此，為了使廢氣通過轉(zhuǎn)輪的沸石模塊時(shí)能被大量快速吸附，一般要求廢氣的溫度低于40℃，印刷等典型工業(yè)行業(yè)普遍能夠滿足這一要求。但是，個(gè)別行業(yè)企業(yè)的廢氣溫度較高，會(huì)導(dǎo)致沸石模塊的吸附處理效率不高。為解決這一問題，需要在前段增加降溫措施。

The characteristic of zeolite is that it has strong adsorption performance at low temperatures and exhibits desorption performance at high temperatures. Therefore, in order to allow the exhaust gas to be quickly adsorbed in large quantities through the zeolite module of the impeller, it is generally required that the temperature of the exhaust gas be below 40 ℃, which is generally met by typical industrial industries such as printing. However, the high exhaust gas temperature of some industry enterprises can lead to low adsorption efficiency of zeolite modules. To address this issue, it is necessary to add cooling measures in the early stages.

降溫裝置設(shè)有冷卻塔、表冷器、循環(huán)水泵、閥門組件、閥組過濾器、管路、儀器儀表及溫控系統(tǒng)。在廢氣溫度高于35℃時(shí)，系統(tǒng)自動(dòng)啟動(dòng)循環(huán)冷卻系統(tǒng)。

The cooling device is equipped with a cooling tower, surface cooler, circulating water pump, valve components, valve group filters, pipelines, instruments and temperature control system. When the exhaust gas temperature exceeds 35 ℃, the system automatically starts the circulating cooling system.

實(shí)際應(yīng)用中會(huì)在過濾裝置后端增加循環(huán)冷卻水對(duì)廢氣進(jìn)行間接式降溫，使進(jìn)入沸石轉(zhuǎn)輪的廢氣溫度保持在35℃，沸石轉(zhuǎn)輪的吸附效率達(dá)到穩(wěn)定。

In practical applications, circulating cooling water will be added at the back end of the filtration device to indirectly cool the exhaust gas, keeping the temperature of the exhaust gas entering the zeolite wheel at 35 ℃, and achieving stable adsorption efficiency of the zeolite wheel.

3廢氣預(yù)處理

3. Waste gas pretreatment

沸石轉(zhuǎn)輪的模塊被制成多層結(jié)構(gòu)，具有一定尺寸的孔道，廢氣通過時(shí)進(jìn)行吸附，如果孔道堵塞，則無法吸附。為了保護(hù)沸石轉(zhuǎn)輪的吸附性能，廢氣進(jìn)入沸石轉(zhuǎn)輪之前需進(jìn)行預(yù)處理，使進(jìn)入轉(zhuǎn)輪濃縮系統(tǒng)的塵埃粒子得到有效去除。

The module of the zeolite wheel is made into a multi-layer structure (as shown in the figure below), with a certain size of pores. When the exhaust gas passes through, it is adsorbed. If the pores are blocked, it cannot be adsorbed. In order to protect the adsorption performance of the zeolite wheel, pre-treatment is required before the exhaust gas enters the zeolite wheel to effectively remove the dust particles entering the wheel concentration system.

圖1 沸石模塊

Figure 1 Zeolite Module

一般在前段至少設(shè)置一級(jí)過濾，可以根據(jù)實(shí)際工況選擇過濾等級(jí)，有必要的話可以多加幾級(jí)過濾。如果前段有冷卻系統(tǒng)的話，有必要增加一級(jí)除濕裝置。常見的過濾形式組合有F5+F9兩級(jí)過濾、DPA+F5+F7+F9四級(jí)過濾等方式。過濾器一般采用袋式過濾器，不同等級(jí)的過濾器為模塊化設(shè)計(jì)，安裝方便。

Generally, at least one level of filtration is set in the front section, and the filtration level can be selected according to the actual working conditions. If necessary, multiple levels of filtration can be added. If there is a cooling system in the front section, it is necessary to add a primary dehumidification device. The common combination of filtration forms includes F5+F9 two-stage filtration, DPA+F5+F7+F9 four stage filtration, and so on. Filters generally use bag filters, and filters of different grades are designed in a modular manner for easy installation.

控制系統(tǒng)中，在每層過濾器前后安裝在線壓差傳感器，可以根據(jù)不同等級(jí)的過濾袋設(shè)置相應(yīng)的壓差報(bào)警值，當(dāng)過濾系統(tǒng)的壓差達(dá)到設(shè)定的報(bào)警值，控制系統(tǒng)發(fā)出報(bào)警信號(hào)，起到提示作用。這也是控制系統(tǒng)的一大特色。

In the control system, online pressure differential sensors are installed before and after each layer of filters, and corresponding pressure differential alarm values can be set according to different levels of filter bags. When the pressure differential of the filtering system reaches the set alarm value, the control system sends an alarm signal to provide a prompt. This is also a major feature of the control system.

通過除塵、除濕處理之后的廢氣更加“干凈”，有助于延長沸石模塊的壽命。過濾后的廢氣進(jìn)入沸石轉(zhuǎn)輪后，轉(zhuǎn)輪以較低的速度連續(xù)轉(zhuǎn)動(dòng)，廢氣由吸附風(fēng)機(jī)吹入轉(zhuǎn)輪吸附區(qū)，處理后的潔凈氣排入大氣，當(dāng)轉(zhuǎn)輪吸附后轉(zhuǎn)到脫附區(qū)，少量潔凈氣與RTO燃燒室高溫氣進(jìn)行熱交換后加熱為熱氣（180℃—200℃），使被吸附的VOCs脫附再生，而脫附下來的高濃度廢氣進(jìn)入旋轉(zhuǎn)式RTO進(jìn)行中高溫氧化。

After dust removal and dehumidification treatment, the exhaust gas becomes cleaner, which helps to extend the lifespan of the zeolite module. After the filtered exhaust gas enters the zeolite impeller, the impeller rotates continuously at a lower speed. The exhaust gas is blown into the impeller adsorption area by the adsorption fan, and the treated clean gas is discharged into the atmosphere. When the impeller adsorbs, it is transferred to the desorption area. A small amount of clean gas exchanges heat with the high-temperature gas in the RTO combustion chamber and is heated into hot gas (180 ℃ -200 ℃), allowing the adsorbed VOCs to desorb and regenerate, The high concentration waste gas desorbed enters the rotary RTO for medium to high temperature oxidation.

4廢氣脫附

4. Waste gas desorption

沸石模塊在一定溫度區(qū)間呈現(xiàn)脫附性能，一般將溫度控制在180℃—200℃，溫度高不要超過220℃，避免余熱過多導(dǎo)致冷卻不完全，影響吸附段的效果。此外，增加脫附再生風(fēng)量、降低濃度倍數(shù)，也可以達(dá)到充分的脫附再生效果。

Zeolite modules exhibit desorption performance within a certain temperature range. Generally, the temperature is controlled between 180 ℃ and 200 ℃, and the temperature should not exceed 220 ℃ to avoid incomplete cooling caused by excessive waste heat and affecting the effectiveness of the adsorption section. In addition, increasing the desorption regeneration air volume and reducing the concentration multiple can also achieve sufficient desorption regeneration effect.

在脫附溫度控制上，控制系統(tǒng)采用了一段式逐漸升溫的辦法?？紤]沸石模塊在脫附過程中可能存在脫附不徹底、有VOCs殘留、故障停機(jī)后無法脫附的情況。因此，在脫附升溫初期，沸石模塊的升溫一定要有梯度，防止脫附過快造成脫附濃度急劇升高和溫度變化劇烈影響沸石模塊壽命。

In terms of desorption temperature control, the control system adopts a step-by-step heating method. Consider the possibility of incomplete desorption, residual VOCs, and inability to desorb after shutdown of the zeolite module during the desorption process. Therefore, in the early stage of desorption heating, the heating of the zeolite module must have a gradient to prevent rapid desorption from causing a sharp increase in desorption concentration and drastic temperature changes that affect the lifespan of the zeolite module.

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