酸氢钠为吸附剂的干法吸附工艺已成为一个烟气净化手段，用于去除烟气中所含的各种污染物。其净化效果可与已知的其它方式相比，如采用石灰乳为吸附剂的喷雾吸附法。干法烟气净化不仅可用于煤电厂、垃圾或替代燃料焚烧厂，还可广泛地用于玻璃、水泥、冶金等行业的工业炉。采用干法烟气净化可以经济地达到烟气排放标准
The dry adsorption process with sodium hydrogen carbonate as adsorbent has become a means of flue gas purification to remove various pollutants contained in flue gas. The purification effect can be compared with other known methods, such as the spray adsorption method using lime milk as adsorbent. Dry flue gas purification can be used not only in coal power plants, waste or alternative fuel incineration plants, but also in industrial furnaces in glass, cement, metallurgy and other industries. Using dry flue gas purification can economically meet the flue gas emission standard
碳酸氢钠用于烟气脱硫的基本原理
Basic principle of sodium bicarbonate for flue gas desulfurization
碳酸氢钠（小苏打， NaHCO3）可以用作烟气脱硫的吸附剂。它通过化学吸附去除烟气中的酸性污染物，同时，它还可通过物理吸附去除一些无机和微量物质。此工艺将碳酸氢钠细粉直接喷入高温烟气。在高温下碳酸氢钠分生成碳酸钠Na2CO3、H2O和CO2。
Sodium bicarbonate (baking soda, NaHCO3) can be used as adsorbent for flue gas desulfurization. It can remove acidic pollutants in flue gas through chemical adsorption. At the same time, it can also remove some inorganic and trace substances through physical adsorption. In this process, the fine sodium bicarbonate powder is directly sprayed into the high-temperature flue gas. Sodium bicarbonate is divided into sodium carbonate Na2CO3, H2O and CO2 at high temperature.
新产生的碳酸钠Na2CO3在生成瞬间有高度的反应** ，可自发地与烟气中的酸性污染物进行下列反应
The newly produced sodium carbonate Na2CO3 has a high degree of reaction * * at the moment of formation, and can spontaneously react with the acid pollutants in the flue gas
一般情况下，烟气温度在140和250 °C之间。由于碳酸氢钠吸附剂的高度**，通常略微过量的碳酸氢钠（化学计量因子在1.1和1.3之间）就足够 。
In general, the flue gas temperature is between 140 and 250 ° C. Due to the high * * of sodium bicarbonate adsorbent, a slight excess of sodium bicarbonate (stoichiometric factor between 1.1 and 1.3) is usually sufficient.
原则上碳酸钠（苏打，Na2CO3）也可用于烟气脱硫。碳酸钠的反应**稍低，但工艺流程几乎不变。本文对碳酸钠脱硫不作进一步阐述。
In principle, sodium carbonate (soda, Na2CO3) can also be used for flue gas desulfurization. The reaction * * of sodium carbonate is slightly lower, but the process flow is almost unchanged. The desulfurization of sodium carbonate is not further described in this paper.
由于运输和存储的原因，碳酸氢钠原料通常是粗颗粒（d50值约为200微米）。如要达到较高的反应性，吸附剂需要有较大的比表面积。因此在注入烟气管道前，碳酸氢钠研磨至一定细度。比如，要去除SO2碳酸氢钠细度须达到d90 < 20 µm。而去除HCl只要求d90 < 35 µm。如果系统操作正确，可以去除95%以上的SO2；HCl的去除率甚至可达 99%。
Due to transportation and storage, the raw material of sodium bicarbonate is usually coarse particles (D50 value is about 200 microns). In order to achieve high reactivity, the adsorbent needs to have a large specific surface area. Therefore, before injecting into the flue gas pipe, the sodium bicarbonate shall be ground to a certain fineness. For example, to remove SO2, the fineness of sodium bicarbonate must reach D90 < 20 & micro; m。 For HCl removal, only D90 < 35 & micro; m。 If the system is operated correctly, more than 95% SO2 can be removed; The removal rate of HCl can even reach 99%.
为了在长期操作中保持所需的碳酸氢钠细度，通常采用带分级机的冲击磨，亦称分级磨，如ZJ-C分级式冲击磨。研磨后，吸附剂以气体输送方式运输并通过多个喷嘴直接通入烟气管道，以保证其在管道内均匀分散。这套设备设计简单耐用，与其它烟气净化方式相比，它的投资和运营成本均较低。
In order to maintain the required fineness of sodium bicarbonate in long-term operation, impact mill with classifier, also known as grading mill, such as zj-c grading impact mill, is usually used. After grinding, the adsorbent is transported by gas transportation and directly connected to the flue gas pipeline through multiple nozzles to ensure its uniform dispersion in the pipeline. The design of this equipment is simple and durable. Compared with other flue gas purification methods, its investment and operation cost are low.
是常规负压流程的示意图，在此流程中碳酸氢钠从贮罐(A)通过一台螺旋输送机
This is a schematic diagram of the conventional negative pressure process in which sodium bicarbonate passes through a screw conveyor from the storage tank (a)
(1)定体积地供给下游的分级磨 (2)所需的吸附剂的量可由脱硫前后的污染物浓度趋势曲线计算，并通过变频器对螺旋输送机进行控制。在螺旋输送机和分级磨之间须安装旋转阀，用于隔离气流，以免气流影响螺旋输送机的定量进料。碳酸氢钠在分级磨中进行研磨后，细粉由一台物料输送风机(3)气体输送至烟气管道(B)。
(1) The amount of adsorbent required by the downstream grading mill (2) can be calculated from the pollutant concentration trend curve before and after desulfurization, and the screw conveyor is controlled by the frequency converter. A rotary valve must be installed between the screw conveyor and the grading mill to isolate the air flow so as not to affect the quantitative feeding of the screw conveyor. After the sodium bicarbonate is ground in the graded mill, the fine powder is transported to the flue gas pipe (b) by a material conveying fan (3).
此操作模式中的积垢问题经常是讨论的焦点。设备的清洗，特别是物料输送风机的清洗过于耗时。此外，在开机和关机过程中风机叶轮上的积垢还可能剥落，导致风机的振动及其运转状态的振荡。
The crud problem in this operation mode is often the focus of discussion. The cleaning of equipment, especially the cleaning of material conveying fan, is too time-consuming. In addition, the scale on the fan impeller may peel off during startup and shutdown, resulting in the vibration of the fan and the oscillation of its operating state.
因此考虑由负压流程改为正压流程。在新的工作模式下风机安装在分级磨之前，将工艺空气压入研磨系统。这种工作模式的优点是研磨后的碳酸氢钠不通过风机运输，完全避免了风机的积垢问题。此外，风机的耗电也有所降低，使经营成本更低
Therefore, it is considered to change from negative pressure process to positive pressure process. In the new working mode, the fan is installed before the grading mill, and the process air is pressed into the grinding system. The advantage of this working mode is that the ground sodium bicarbonate is not transported through the fan, which completely avoids the scaling problem of the fan. In addition, the power consumption of the fan is also reduced, making the operating cost lower
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