Catalytic reaction processes using microchannel technology for hydrogen production by steam reforming

Catalytic reaction processes using microchannel technology for hydrogen production by steam reforming

Junjie Chen

Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China

Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: [e-mail]

Two competing proposals have been made concerning the mechanism of catalytic reactions at surfaces, and it has not been possible to choose between them. Originally, Irving Langmuir, an American physical chemist, proposed chemisorption of both reacting species at the surface, followed by interaction between adjacent species and evaporation of the products. An alternative proposal involves interaction between an impinging molecule and species already adsorbed on the surface. Subsequent developments have suggested various modes of attachment of the adsorbed and adsorbing species. A major advance in the science of surface catalysis was the development of a method for determining the surface area of catalysts (and other materials) by measuring the multimolecular adsorption of nitrogen at liquid nitrogen temperatures or the adsorption of other gases close to their boiling points. It then became possible to calculate a quantity that represents the volume of gas necessary to form a monolayer on the accessible surface; furthermore, the area of the surface can be determined from the known dimensions of the adsorbed molecules. It has also been found possible to titrate (measure quantitatively) the area of surfaces by chemisorption of gases. Since heterogeneously catalyzed reactions occur on the surface of the catalyst, the rates of such reactions are proportional to the accessible surface area of the catalyst. Active catalysts are thus usually highly porous solids with total surface areas as high as several hundred square metres per gram. When measurements of surface areas became possible, it was seen at once that many constituents present in minor quantities in the main catalyst material, known as promoters, could act by extending the effective surface area of the catalyst. It also was shown, however, that a promoter might produce an increase in the quality of the surface for the given reaction. Acting in a reverse direction are minor constituents of the reacting system or unwanted products of the reaction, which by preferential adsorption on the reaction sites. Poisoning of a catalyst may also result from the poison adversely modifying the electronic properties of the catalyst.

Streamwise distance (meter), Heterogeneous reaction rate along the length of the reactor (mole per square meter per second)

0                                 12.5259

0.00025                             12.5249

0.0005                               12.4628

0.00075                             12.2996

0.001                                 12.0712

0.00125                             11.8221

0.0015                               11.596

0.00175                             11.4118

0.002                                 11.2616

0.00225                             11.1177

0.0025                               10.9536

0.00275                             10.759

0.003                                 10.5398

0.00325                             10.3175

0.0035                               10.1169

0.00375                             9.94876

0.004                                 9.80787

0.00425                             9.67857

0.0045                               9.54646

0.00475                             9.40536

0.005                                 9.25748

0.00525                             9.11421

0.0055                               8.98858

0.00575                             8.88572

0.006                                 8.80178

0.00625                             8.72615

0.0065                               8.64819

0.00675                             8.5635

0.007                                 8.47426

0.00725                             8.38872

0.0075                               8.31553

0.00775                             8.2578

0.008                                 8.21239

0.00825                             8.17077

0.0085                               8.1251

0.00875                             8.07247

0.009                                 8.01529

0.00925                             7.9603

0.0095                               7.91452

0.00975                             7.88049

0.01                                   7.85474

0.01025                             7.83035

0.0105                               7.80092

0.01075                             7.76453

0.011                                 7.72333

0.01125                             7.68313

0.0115                               7.65017

0.01175                             7.62633

0.012                                 7.60882

0.01225                             7.59146

0.0125                               7.5688

0.01275                             7.53904

0.013                                 7.50421

0.01325                             7.4698

0.0135                               7.4414

0.01375                             7.42087

0.014                                 7.40548

0.01425                             7.38911

0.0145                               7.36723

0.01475                             7.33882

0.015                                 7.30582

0.01525                             7.27313

0.0155                               7.24519

0.01575                             7.22352

0.016                                 7.20619

0.01625                             7.18805

0.0165                               7.16393

0.01675                             7.13321

0.017                                 7.09884

0.01725                             7.06502

0.0175                               7.03546

0.01775                             7.01145

0.018                                 6.99108

0.01825                             6.96922

0.0185                               6.94195

0.01875                             6.90861

0.019                                 6.8712

0.01925                             6.83338

0.0195                               6.79882

0.01975                             6.76887

0.02                                   6.74161

0.02025                             6.71249

0.0205                               6.67791

0.02075                             6.63756

0.021                                 6.59338

0.02125                             6.54862

0.0215                               6.50642

0.02175                             6.46809

0.022                                 6.43121

0.02225                             6.39171

0.0225                               6.34695

0.02275                             6.29666

0.023                                 6.24214

0.02325                             6.18634

0.0235                               6.13241

0.02375                             6.0807

0.024                                 6.02879

0.02425                             5.9737

0.0245                               5.9136

0.02475                             5.84831

0.025                                 5.779

0.02525                             5.70789

0.0255                               5.63732

0.02575                             5.56765

0.026                                 5.49729

0.02625                             5.42368

0.0265                               5.34518

0.02675                             5.26167

0.027                                 5.17445

0.02725                             5.08554

0.0275                               4.99626

0.02775                             4.90677

0.028                                 4.81571

0.02825                             4.7225

0.0285                               4.62433

0.02875                             4.52329

0.029                                 4.40952

0.02925                             4.30083

0.0295                               4.20122

0.02975                             4.10465

0.03                                   4.05785

Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: [e-mail], Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China

# 采用微通道技术的水蒸气重整制氢催化反应工艺

陈俊杰（Junjie Chen）

河南理工大学机械与动力工程学院能源与动力工程系，世纪大道2000号，焦作，河南，454000，中华人民共和国

贡献者：陈俊杰（Junjie Chen），ORCID: 0000-0001-5055-4309，电子邮箱：[e-mail]

针对表面催化反应的机理，目前存在两种相互竞争的假说，尚无定论。最初，美国物理化学家欧文·朗缪尔（Irving Langmuir）提出，两种反应组分均在表面发生化学吸附（chemisorption），随后相邻吸附物种之间发生反应，最终产物脱附蒸发。另一种假说则认为，反应是由入射至表面的分子与已吸附在表面的物种之间发生反应实现的。后续的研究进展提出了吸附物种与被吸附物种之间多种不同的结合模式。

表面催化科学领域的一项重大进展，是开发出了通过在液氮温度下测定氮气的多分子吸附量，或是在接近气体沸点的温度下测定其他气体的吸附量，来计算催化剂（及其他材料）比表面积的方法。借此可计算出在催化剂可接触表面形成单分子层（monolayer）所需的气体体积；进一步地，通过吸附分子的已知尺寸，便可计算得到催化剂的比表面积。此外，研究人员还发现可通过气体化学吸附法对表面面积进行定量滴定（即定量测量）。

由于多相催化反应发生在催化剂表面，因此这类反应的速率与催化剂的可接触比表面积成正比。高性能催化剂通常为高孔隙率固体，其总比表面积可达每克数百平方米。当比表面积的测量成为可能后，人们很快发现，主催化剂材料中少量添加的助剂（promoter）可通过扩展催化剂的有效比表面积发挥作用；此外研究还表明，助剂也可通过优化催化剂表面针对特定反应的反应性能来提升催化效果。

而反应体系中的少量组分或是反应副产物则会产生相反的作用：它们会优先吸附在催化反应位点上，导致催化剂中毒；此外，毒物还可能通过破坏催化剂的电子性质，引发催化剂中毒。

## 实验数据

沿流动方向的距离（米），反应器沿程多相反应速率（摩尔每平方米每秒）
0 12.5259
0.00025 12.5249
0.0005 12.4628
0.00075 12.2996
0.001 12.0712
0.00125 11.8221
0.0015 11.596
0.00175 11.4118
0.002 11.2616
0.00225 11.1177
0.0025 10.9536
0.00275 10.759
0.003 10.5398
0.00325 10.3175
0.0035 10.1169
0.00375 9.94876
0.004 9.80787
0.00425 9.67857
0.0045 9.54646
0.00475 9.40536
0.005 9.25748
0.00525 9.11421
0.0055 8.98858
0.00575 8.88572
0.006 8.80178
0.00625 8.72615
0.0065 8.64819
0.00675 8.5635
0.007 8.47426
0.00725 8.38872
0.0075 8.31553
0.00775 8.2578
0.008 8.21239
0.00825 8.17077
0.0085 8.1251
0.00875 8.07247
0.009 8.01529
0.00925 7.9603
0.0095 7.91452
0.00975 7.88049
0.01 7.85474
0.01025 7.83035
0.0105 7.80092
0.01075 7.76453
0.011 7.72333
0.01125 7.68313
0.0115 7.65017
0.01175 7.62633
0.012 7.60882
0.01225 7.59146
0.0125 7.5688
0.01275 7.53904
0.013 7.50421
0.01325 7.4698
0.0135 7.4414
0.01375 7.42087
0.014 7.40548
0.01425 7.38911
0.0145 7.36723
0.01475 7.33882
0.015 7.30582
0.01525 7.27313
0.0155 7.24519
0.01575 7.22352
0.016 7.20619
0.01625 7.18805
0.0165 7.16393
0.01675 7.13321
0.017 7.09884
0.01725 7.06502
0.0175 7.03546
0.01775 7.01145
0.018 6.99108
0.01825 6.96922
0.0185 6.94195
0.01875 6.90861
0.019 6.8712
0.01925 6.83338
0.0195 6.79882
0.01975 6.76887
0.02 6.74161
0.02025 6.71249
0.0205 6.67791
0.02075 6.63756
0.021 6.59338
0.02125 6.54862
0.0215 6.50642
0.02175 6.46809
0.022 6.43121
0.02225 6.39171
0.0225 6.34695
0.02275 6.29666
0.023 6.24214
0.02325 6.18634
0.0235 6.13241
0.02375 6.0807
0.024 6.02879
0.02425 5.9737
0.0245 5.9136
0.02475 5.84831
0.025 5.779
0.02525 5.70789
0.0255 5.63732
0.02575 5.56765
0.026 5.49729
0.02625 5.42368
0.0265 5.34518
0.02675 5.26167
0.027 5.17445
0.02725 5.08554
0.0275 4.99626
0.02775 4.90677
0.028 4.81571
0.02825 4.7225
0.0285 4.62433
0.02875 4.52329
0.029 4.40952
0.02925 4.30083
0.0295 4.20122
0.02975 4.10465
0.03 4.05785

贡献者：陈俊杰（Junjie Chen），ORCID: 0000-0001-5055-4309，电子邮箱：[e-mail]，河南理工大学机械与动力工程学院能源与动力工程系，世纪大道2000号，焦作，河南，454000，中华人民共和国