在整個(gè)濕法脫硫過程中，從吸收到再生，再到硫回收，有些工藝條件是相互矛盾的。新設(shè)計(jì)的脫硫裝置一般都會(huì)綜合考慮到各種相互影響的因素，把系統(tǒng)的脫硫、再生、以及硫回收做為一個(gè)系統(tǒng)工程，全面考慮，統(tǒng)籌解決。但是，對于不斷進(jìn)行擴(kuò)產(chǎn)改造或者是利用舊設(shè)備的裝置，常常存在著各種不相匹配的因素，所以需要正確認(rèn)識(shí)，合理兼顧這些指標(biāo)。
In the whole wet desulfurization process, some process conditions are contradictory from absorption to regeneration and then to sulfur recovery. Generally, the newly designed desulfurization unit will comprehensively consider various interactive factors, and take the desulfurization, regeneration and sulfur recovery of the system as a systematic project, comprehensively consider and solve it as a whole. However, there are often various mismatched factors for the continuous expansion and transformation of production or the use of old equipment, so we must correctly understand and give reasonable consideration to these indicators.
1 吹風(fēng)強(qiáng)度與再生空氣量
1. Blowing intensity and regeneration air volume
我們知道，再生的作用有幾點(diǎn)。一，供給脫硫所需要的化學(xué)反應(yīng)的氧量。二，富液中的HS-在再生時(shí)繼續(xù)被氧化，同時(shí)恢復(fù)催化劑的活性。三，在空氣的鼓泡和吹攪下，硫粒聚集成硫泡沫浮在上面，便于浮選把硫黃分離出去。第四，把溶液中在脫硫的同時(shí)被吸收的CO2氣提出去，從而提高溶液堿度，降低堿的消耗。由此可知，如果單純從再生角度出發(fā)，吹風(fēng)強(qiáng)度越大，再生越完全、越徹底。但是，過大的吹風(fēng)強(qiáng)度卻會(huì)對硫泡沫的正常浮選帶來不利影響。過大的空氣量會(huì)造成液面翻騰較大，硫泡沫層不穩(wěn)定，硫浮選分離差，造成懸浮硫高。若空氣量長期過大，則溶液電位將偏高，會(huì)使副反應(yīng)加快。過度氧化還會(huì)造成硫酸鈉的升高，帶來設(shè)備腐蝕。所以，再生槽的吹風(fēng)強(qiáng)度要適宜，一般噴射再生流程的吹風(fēng)強(qiáng)度為60m3/m2.h～100m3/m2.h。各企業(yè)在生產(chǎn)實(shí)踐中，可以根據(jù)自身的設(shè)備和工藝狀況，摸索出適合自己工況的佳空氣量。
We know that regeneration has several functions. First, supply the oxygen for the chemical reaction required for desulfurization. Second, HS - in the rich liquid continues to be oxidized during regeneration and restores the activity of the catalyst. Third, under the bubbling and stirring of air, sulfur particles gather into sulfur foam and float on it, which is convenient for flotation to separate sulfur. Fourth, the CO2 gas absorbed in the solution while desulfurization is carried out, so as to improve the alkalinity of the solution and reduce the consumption of alkali. It can be seen from this that the greater the blowing intensity is, the more complete and thorough the regeneration is if only from the perspective of regeneration. However, excessive blowing intensity will bring adverse effects on the normal flotation of sulfur foam. Excessive air volume will cause large liquid level churning, unstable sulfur foam layer and poor sulfur flotation separation, resulting in high suspended sulfur. If the air volume is too large for a long time, the solution potential will be high, which will accelerate the side reaction. Excessive oxidation will also cause the rise of sodium sulfate and equipment corrosion. Therefore, the blowing intensity of the regeneration tank should be appropriate. Generally, the blowing intensity of the jet regeneration process is 60m3 / m2 h～100m3/m2. h。 In production practice, enterprises can find out the best air volume suitable for their own working conditions according to their own equipment and process conditions.
2 溶液循環(huán)量與再生停留時(shí)間
2 solution circulation volume and regeneration residence time
溶液的循環(huán)量與再生停留時(shí)間是反比關(guān)系。在其它條件不變的情況下，當(dāng)氣量大，H2S含量高時(shí)，為保證脫硫效率，應(yīng)適當(dāng)增加溶液循環(huán)量，即增大液氣比和噴淋密度。但是，在增加循環(huán)量的同時(shí)，一定要考慮溶液在再生槽中的停留時(shí)間。否則，因?yàn)檠h(huán)量的增加，縮短了溶液在再生槽的停留時(shí)間，造成再生不完全，溶液質(zhì)量差，同樣達(dá)不到較高的脫硫效率。以前我公司做過一個(gè)方案，脫硫塔直徑為φ4800，原有的貧液泵額定流量為420m3/h，其噴淋密度20m3/m2.h多，明顯偏小了。所以，必須增加溶液的循環(huán)量。如果單純從噴淋密度考慮，以增加至800 m3/h為佳，此時(shí)噴淋密度為44 m3/m2.h。但是該廠再生槽容積是為循環(huán)量400 m3/h左右而設(shè)計(jì)，如果流量增加至800 m3/h，則溶液在再生槽中的停留時(shí)間太短，無法滿足再生需求，再生槽容積肯定要做相應(yīng)調(diào)整，這樣就給施工帶來很大的工作量?？紤]到該廠脫硫塔進(jìn)口硫含量不高，脫硫負(fù)荷不大，所以，建議把流量增加到600 m3/h，這樣噴淋密度為33 m3/m2.h，基本能滿足要求，而且，該流量下再生槽內(nèi)溶液的停留時(shí)間為12分鐘。
The circulation amount of solution is inversely proportional to the regeneration residence time. When other conditions remain unchanged, when the gas volume is large and the H2S content is high, in order to ensure the desulfurization efficiency, the solution circulation volume should be appropriately increased, that is, the liquid-gas ratio and spray density should be increased. However, while increasing the circulation volume, the residence time of the solution in the regeneration tank must be considered. Otherwise, the residence time of the solution in the regeneration tank is shortened due to the increase of the circulation volume, resulting in incomplete regeneration and poor solution quality, which also can not achieve high desulfurization efficiency. Our company has made a scheme before, and the diameter of desulfurization tower is φ 4800, the rated flow of the original lean solution pump is 420m3 / h, and its spray density is 20m3 / m2 H is too much, which is obviously too small. Therefore, the circulation amount of solution must be increased. If only considering the spray density, it is better to increase to 800 m3 / h, and the spray density is 44 m3 / m2 h。 However, the volume of the regeneration tank in the plant is designed for the circulation volume of about 400 m3 / h. If the flow increases to 800 m3 / h, the residence time of the solution in the regeneration tank is too short to meet the regeneration demand. The volume of the regeneration tank must be adjusted accordingly, which will bring a lot of work to the construction. Considering that the sulfur content at the inlet of the desulfurization tower of the plant is not high and the desulfurization load is small, it is recommended to increase the flow to 600 m3 / h, so that the spray density is 33 m3 / m2 h. Basically meet the requirements, and the residence time of the solution in the regeneration tank under this flow is 12 minutes.
溶液循環(huán)量與再生空氣量也有著密切關(guān)系。因?yàn)閲娚溲趸偕鄣墓に?，是靠富液通過噴射器吸入空氣的，而富液吸入空氣量基本上是恒定的。如果循環(huán)量太小，則吸入空氣量不足，可能就滿足不了再生氧化槽所需的空氣量，就可能開車后不久出現(xiàn)再生效果不理想、懸浮硫高、硫回收率低、吸收劑與催化劑消耗高等問題，嚴(yán)重時(shí)還會(huì)引起堵塔。
The amount of solution circulation is also closely related to the amount of regeneration air. Because the process of spraying oxidation regeneration tank depends on the rich liquid to inhale air through the ejector, and the amount of air inhaled by the rich liquid is basically constant. If the circulation volume is too small, the intake air volume is insufficient, which may not meet the air volume required by the regenerative oxidation tank. Soon after start-up, there may be problems such as unsatisfactory regeneration effect, high suspended sulfur, low sulfur recovery rate, high consumption of absorbent and catalyst, and even tower blockage.
3 溶液總堿度與PH值
3 total alkalinity and pH value of solution
溶液的總堿度與其硫容量成正比關(guān)系，因此，提高總堿度是提高硫容量的有效途徑。換句話說，中和反應(yīng)過程中，在其它工況不變的情況下，提高總堿度可以更好的保證脫硫效率。但是，若總堿度過高，原料消耗增加且副反應(yīng)加快。
The total alkalinity of the solution is directly proportional to its sulfur capacity. Therefore, increasing the total alkalinity is an effective way to improve the sulfur capacity. In other words, in the process of neutralization reaction, increasing the total alkalinity can better ensure the desulfurization efficiency under the condition that other working conditions remain unchanged. However, if the total alkalinity is too high, the consumption of raw materials will increase and the side reactions will accelerate.
PH值是脫硫液的基本指標(biāo)，PH值太低，不利于硫化氫的吸收，并會(huì)降低氧的溶解度，溶液再生效果差；PH值太高，會(huì)加快副反應(yīng)，副鹽生成率高，影響析硫速度，硫回收差，且增加堿耗。
PH value is the basic index of desulfurization solution. Too low pH value is not conducive to the absorption of hydrogen sulfide, will reduce the solubility of low oxygen, and the regeneration effect of solution is poor; If the pH value is too high, the side reaction will be accelerated, the generation rate of side salt will be high, the sulfur separation speed will be affected, the sulfur recovery will be poor, and the alkali consumption will be increased.
至于總堿度與PH值的關(guān)系，一般來說，PH值隨總堿度的增加而上升，但嚴(yán)格的講，PH值主要是受NaHCO3/ Na2CO3的影響，PH與比值呈反比關(guān)系，還有就是硫酸根離子的影響。
As for the relationship between total alkalinity and pH value, generally speaking, pH value increases with the increase of total alkalinity, but strictly speaking, pH value is mainly affected by NaHCO3 / Na2CO3, pH is inversely proportional to the ratio, and there is the influence of sulfate ion.
在實(shí)際生產(chǎn)中，由于各廠情況不同，脫硫進(jìn)口氣體中H2S含量差別較大，工藝與設(shè)備配置的合理性也有很大差異，因此，對于總堿度的控制原則和指導(dǎo)思想應(yīng)該是：在保證適宜溶液循環(huán)量和較高脫硫效率的前提下，保證出口硫化氫，溶液的總堿度控制在低限，降低生產(chǎn)消耗和副反應(yīng)物的生成，從而保持工況的穩(wěn)定。
In the actual production, due to the different conditions of each plant, the H2S content in the desulfurization inlet gas varies greatly, and the rationality of process and equipment configuration also varies greatly. Therefore, the control principle and guiding ideology for the total alkalinity should be: on the premise of ensuring the appropriate solution circulation and high desulfurization efficiency, ensure the outlet hydrogen sulfide, control the total alkalinity of the solution at the low limit, and reduce the production consumption and the generation of side reactants, So as to maintain the stability of working conditions.
4 重視分析工作
4 attach importance to analysis
分析數(shù)據(jù)是我們的眼睛，我們合理調(diào)整消耗以及指導(dǎo)工作的依據(jù)，所以建立、完善、規(guī)范脫硫分析，從而更好利用這些分析數(shù)據(jù)指導(dǎo)生產(chǎn)，保證生產(chǎn)連續(xù)穩(wěn)定的運(yùn)行。
The analysis data is our eyes. We reasonably adjust the consumption and guide the work, so we establish, improve and standardize the desulfurization analysis, so as to make better use of these analysis data to guide the production and ensure the continuous and stable operation of the production.
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