沼气脱硫剂在使用过程中,其床层内硫的轴向可分为3个区域。如原料气从上部进入,则上层为饱和区,随着反应的不断进行,区内生成的硫化物量逐渐增加,而反应逐渐减慢,饱和区高度随着脱硫时间增长而增加。中层为传质区(主要反应区)该反应相当迅速,直至达到平衡浓度。下层为清洁区,也就是没有与H2S反应过的新鲜氧化铁脱硫层。随着脱硫时间的增长,整个轴向分布逐步向下移动,直至清洁区消失,出气口泄硫,当出气口硫化氢含量大于工艺指标时,即为穿透。影响脱硫反应的主要因素除沼气脱硫剂本身性质外还有以下一些因素:
During the use of biogas desulfurizer, the axial direction of sulfur in the bed can be divided into three areas. If the feed gas enters from the upper part, the upper part is a saturated zone. With the continuous reaction, the amount of sulfide generated in the zone gradually increases, while the reaction slows down. The height of the saturated zone increases with the increase of desulfurization time. The middle layer is the mass transfer zone (the main reaction zone). The reaction is quite rapid until the equilibrium concentration is reached. The lower layer is a clean area, that is, a fresh iron oxide desulfurization layer that has not reacted with H2S. With the increase of desulfurization time, the whole axial distribution gradually moves downward until the clean area disappears and the sulfur is released from the gas outlet. When the hydrogen sulfide content at the gas outlet is greater than the process index, it is penetration. In addition to the nature of the biogas desulfurizer itself, the main factors affecting the desulfurization reaction include the following factors:
(1)煤气中其它杂质:煤气中的焦油、萘、灰尘等杂质,会使沼气脱硫剂结成硬块,导致箱内阻力升高,脱硫效率下降,沼气脱硫剂使用寿命降低。煤气中的含氨量过多或过少时,均将使沼气脱硫剂处于酸性状态,引起脱硫效率下降。
(1) Other impurities in the gas: tar, naphthalene, dust and other impurities in the gas will cause the biogas desulfurizer to form hard blocks, resulting in increased resistance in the box, decreased desulfurization efficiency and reduced service life of the biogas desulfurizer. When the ammonia content in the gas is too much or too little, the biogas desulfurizer will be in an acidic state, resulting in the decline of desulfurization efficiency.
(2)温度
(2) Temperature
温度对脱硫效率影响很大,温度过高(40℃一50℃),将使氧化速度大大快,相对降低了硫化氢的反应速度,还会使Fe2S3?H2O失去所带水分而成为不带水Fe2S3;在氧化时将产生硫酸盐,从而使沼气脱硫剂呈酸性。温度过低时,将大大降低沼气脱硫剂与硫化氢的反应速度,煤气中的水分也因温度过多而冷凝下来,使脱硫效率下降。
The temperature has a great influence on the desulfurization efficiency. If the temperature is too high (40 ℃ - 50 ℃), the oxidation speed will be greatly faster, the reaction speed of hydrogen sulfide will be relatively reduced, and fe2s3? H2O loses water and becomes fe2s3 without water; Sulfate will be produced during oxidation, which makes the biogas desulfurizer acidic. When the temperature is too low, the reaction speed between biogas desulfurizer and hydrogen sulfide will be greatly reduced, and the water in the gas will condense due to excessive temperature, which will reduce the desulfurization efficiency.
(3)水分
(3) Moisture
适量的水分在沼气脱硫剂中的作用有:
The role of appropriate amount of water in biogas desulfurizer is as follows:
1) 能保持硫化氢与氧化铁足够的接触时间
1) Sufficient contact time between hydrogen sulfide and iron oxide can be maintained
2) 是免除沼气脱硫剂结块的因素之一
2) It is one of the factors to avoid agglomeration of biogas desulfurizer
3) 能溶解一部分在净化过程中所产生的盐类,这些盐类大部分包裹在氧化铁的表面,影响脱硫效果。
3) It can dissolve part of the salts produced in the purification process. Most of these salts are wrapped on the surface of iron oxide, affecting the desulfurization effect.
(4)含氧量
(4) Oxygen content
煤气在进入脱硫箱前含有一定量的氧气,使箱内硫化铁得以再生至一定程度,有利于延长脱硫剂的使用周期。但若含氧量过高能加速对铁板的腐蚀和生成煤气胶;过低时不利于沼气脱硫剂再生。
The gas contains a certain amount of oxygen before entering the desulfurization tank, so that the iron sulfide in the tank can be regenerated to a certain extent, which is conducive to extending the service life of the desulfurizer. However, if the oxygen content is too high, the corrosion of iron plate and the formation of gas glue can be accelerated; Too low is not conducive to regeneration of biogas desulfurizer.
(5)pH值(酸碱度)
(5) PH value (PH)
因为碱度对沼气脱硫剂有稳定的作用,在碱性适合的情况下Fe2S3?H2O能很好的氧化成为Fe203?H20,是优良的脱硫原料,在碱性环境下能加速氧化铁和硫化氢之间的反应速度。
Because alkalinity has a stable effect on biogas desulfurizer, fe2s3? H2O can be oxidized to Fe203? H20 is an excellent desulfurization raw material, which can accelerate the reaction speed between iron oxide and hydrogen sulfide in alkaline environment.
(6)煤气在箱内的流向对脱硫效率的影响
(6) Influence of gas flow direction in tank on desulfurization efficiency
煤气在箱内的流向,可分为向上、向下两种。向上流阻力上升得快,煤气须经过栅格而进入底层脱硫剂,造成底层析硫严重,所以阻力升高快。如果焦油脱除效果差,则底层沼气脱硫剂迅速被粘住堵塞,影响脱硫效率。向下流阻力上升慢,但在阻力突然升高后,只需更换上层脱硫剂即可。
The flow direction of gas in the tank can be divided into upward and downward. The upward flow resistance rises rapidly, and the gas must pass through the grid and enter the bottom desulfurizer, causing serious sulfur in the bottom chromatography, so the resistance rises rapidly. If the tar removal effect is poor, the bottom biogas desulfurizer is quickly stuck and blocked, affecting the desulfurization efficiency. The downward flow resistance rises slowly, but after the resistance rises suddenly, it is only necessary to replace the upper desulfurizer.
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