Development of the Next Generation CaO-Sorbent for Sulfur- and Nitrogen-Compound Removal

开发用于去除硫和氮化合物的下一代 CaO 吸附剂

• 批准号: 11218207
• 负责人: SASAOKA Eiji
• 金额: $ 19.2万
• 依托单位: Okayama University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11218207/
• 关键词: Limestone; Lime; Porous Lime; SOx; NOx; H_2S; CaS; Decomposition of CaS; 石炭高効率燃焼; 脱SO_x・N_2O剤; 脱NO_x剤; 脱N_2S剤; 硫酸カルシウムの硫酸塩・酸化物化; 多孔質生石; 脱SO_X・N_2O剤; 脱NO_X剤; 脱H_2S剤; 硫化カルシウムの硫酸鉛・酸化物化; 石炭の高効率燃焼; N_2O分解触媒; 脱SOx剤; 脱NOx剤; 加圧燃焼; 石灰の高効率燃焼

Limestone and lime are very important materials as sorbents for S-and N-compound removal. However their porosities are usually low, and their capacity are low. To solute this problem, the clarifications of the reaction mechanisms and the clarification of the effect of pore size distribution on the reactivity are very important in addition to the development of a preparation method of a porous lime which porosityis suitable for the removal. We present new preparation methods of macro-porous CaO using acetic acid, water and a mixture of acetic acid and water. By using these methods, we could prepare the samples, which pore size distributions were different each other, from a natural lime. The effects of pore size distribution of the CaO- and CaCO_3- sorbent on the removal of SO_x using the serial samples were studied. It was concluded that if we can prepared a lime that has an adequate number of macropore, mesopore and micropore, and good serial connection of these different size pore to … More ensure the permeability of reactant(SO_2 and O_2) and prevent pore plugging during sulfation, the reactivity and utility of the lime will be drastically improved. From the results of study on the CaCO_3-sorbent, it was also suggested that if the macropores in the CaCO_3 sample are developed enough to SO_2 removal, the reactivity of the CaCO_3 sample is same as that of CaOWhen CaO is used for H_2S removal, CaS formed from the CaO-absorbent has to be converted to CaSO_4 before disposal because H_2S is released from the reaction between CaS and water. To find out a method for the perfect conversion of CaS to CaSO_4 and CaO, the basic characters of the oxidative decomposition of CaS were examined using reagent grade CaS in the presence of H_2O because hot combustion gas contained moisture is usually used for the decomposition of CaS. It was found that the presence of H_2O affected drastically to the conversion of CaS to CaO and SO_2 : H_2O directly reacted with CaS and formed H_2 reacted immediately with O_2.The mechanism of the simultaneous removal of SOx and NOx by slaked lime was clarified : A reaction scheme of this reaction was proposed : SO_2 reacted with H_2O and formed SO_3^<2->, then NO and NO_2 might participate the reaction in one step and the other hand, accelerated the conversion of SO_3^<2-> to SO_4^<2->. The main part of NO_2 was converted to nitrate salts in the presence of H_2O. SO_3^<2-> formed from the adsorption is supposed to be significant for the removal of NO, and the enhancement of NO to the SO_2 was ascribed to its catalytic effect in the oxidation of SO_3^<2-> to SO_4^<2->. Less

石灰石和石灰是非常重要的脱硫脱氮材料。然而，它们的孔隙率通常较低，并且它们的容量较低。为了解决这个问题，除了开发一种孔隙率适合于去除的多孔石灰的制备方法之外，澄清反应机理和澄清孔径分布对反应性的影响是非常重要的。提出了用乙酸、水及乙酸和水的混合物制备大孔CaO的新方法。通过这些方法，我们可以从天然石灰中制备出不同孔径分布的样品。采用系列样品研究了CaO和CaCO_3吸附剂的孔径分布对脱硫效果的影响。结果表明，如果我们能制备出具有足够数量的大孔、中孔和微孔的石灰，并且这些不同尺寸的孔之间有良好的串联， ...更多信息 保证了反应物（SO_2和O_2）的渗透性，防止了硫酸化过程中的孔隙堵塞，石灰的反应活性和利用率将大大提高。CaCO_3吸附剂的研究结果还表明，如果CaCO_3样品中的大孔足够发达，则CaCO_3样品具有与CaO相同的脱硫活性。当CaO用于H_2S脱除时，由于CaS与水反应释放出H_2S，因此CaO吸附剂中生成的CaS在处理前必须转化为CaSO_4。由于CaS的分解通常采用含水分的高温燃气，为了寻找CaS完全转化为CaSO_4和CaO的方法，采用试剂级CaS在H_2O存在下，考察了CaS氧化分解的基本特性。结果表明，H_2O的存在对CaS向CaO的转化有显著影响，SO_2：H_2O直接与CaS反应生成H_2，H_2与O_2反应生成H_2。阐明了消石灰同时脱硫脱硝的机理：提出了该反应的反应方案：SO_2与H_2O反应生成SO_3 ~（2-）<2->，NO和NO_2可能一步参与反应，另一方面促进了SO_3 ~（2-）<2->向SO_4 ~（2-）的转化<2->。在H_2O存在下，NO_2主要转化为硝酸盐。吸附<2->过程中生成的SO_3 ~（2-）对NO的脱除有重要作用，NO对SO_2的强化作用是由于其对SO_3 ~（2-）氧化为SO_4 ~（2-）的催化作用<2-><2->。少

项目成果

M, Sakai, C.Su, E.Sasaoka: "Simultaneous Removal of SO_x and NO_x Using Slaked Lime at Low Temperature, Vol.41, 5029-5033 (2002)."Ind. Eng. Chem. Res.. 41. 5029-5033 (2002)

M，Sakai，C.Su，E.Sasaoka：“在低温下使用熟石灰同时去除 SO_x 和 NO_x，第 41 卷，5029-5033 (2002)”。

S. Wu, M. A. Uddin, S. Nagamine and E. Sasaoka: "Role of water vapor in oxidative decomposition of calcium sulfide"225th ACS National Meeting, New Orleans. 23-27. (2003)

S. Wu、M. A. Uddin、S. Nagamine 和 E. Sasaoka：“水蒸气在硫化钙氧化分解中的作用”第 225 届 ACS 全国会议，新奥尔良。

呉 聖姫, 笹岡 英司 他: "高温脱H2Sにより生じた硫化カルシウムの酸化分解"第38回石灰科学会議発表論文集. 327-330 (2001)

Seiki Kure、Eiji Sasaoka 等人：“H2S 高温脱水产生的硫化钙的氧化分解”第 38 届石灰科学会议论文集 327-330 (2001)。

野島繁,笹岡英司 他: "アルミナ担持硫酸ニッケル触媒による低温脱硝反応"日本化学会誌. 2000. 621-627 (2000)

Shigeru Nojima、Eiji Sasaoka 等：“使用氧化铝负载的硫酸镍催化剂的低温脱氮反应”日本化学学会杂志 2000 年。621-627 (2000)。

S. Wu, C. Su and E. Sasaoka: "Reactivity of Modified Lime Limestone for High-Temperature DeSO_x in the presence of High Concentration CO_2"18th Annual International Pittsburgh Coal Conference, Newcastle, Dec. 3-7. (2001)

S. Wu、C. Su 和 E. Sasaoka：“在高浓度 CO_2 存在下，改性石灰石在高温 DeSO_x 中的反应性”，第 18 届国际匹兹堡煤炭年会，纽卡斯尔，12 月 3-7 日。