Catalyst Poisons
Poisonous contaminants derive usually from fuel, lube oil, urea solution or from silencers as described previously.
Not much is known about the effects in cases where more than one toxic compound is present.
However, some substances have been characterized and their adverse effects are better known. Two reasons most likely for loss of activity are: Firstly, by plugging the pores in the catalyst matrix the access to the active centers will be blocked for the reactants. Secondly, some compounds like e.g. alkali and alkali earth metal oxides may mask directly the active centers.
Please refer to the illustration of the periodic table of elements below for potentially toxic elements prevalence as well as for their effects on catalysts.
|
Krypton |
Weight [Atomic Mass Units] | 234,555 |
Density | 11,5 |
Melting Point [°K] | 23 |
Boiling Point [°K] | 200 |
Abundance in Earth Crust [ppm] | 12 |
Tolerance for HFO, Diesel & Natural gas [mg/kg] | 12 |
Tolerance for Biofuels [mg/kg] | 12 |
Table of Poisons for SCR Catalysts
1 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
18 |
1 H |
2 |
|
|
|
|
|
|
|
|
|
|
13 |
14 |
15 |
16 |
17 |
2 He |
3 Li |
4 Be |
|
|
|
|
|
|
|
|
|
|
5 B |
6 C |
7 N |
8 O |
9 F |
10 Ne |
11 Na |
12 Mg |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 Al |
14 Si |
15 P |
16 S |
17 Cl |
18 Ar |
19 K |
20 Ca |
21 Sc |
22 Ti |
23 V |
24 Cr |
25 Mn |
26 Fe |
27 Co |
28 Ni |
29 Cu |
30 Zn |
31 Ga |
32 Ge |
33 As |
34 Se |
35 Br |
36 Kr |
37 Rb |
38 Sr |
39 Y |
40 Zr |
41 Nb |
42 Mo |
43 Tc |
44 Ru |
45 Rh |
46 Pd |
47 Ag |
48 Cd |
49 In |
50 Sn |
51 Sb |
52 Te |
53 I |
54 Xe |
55 Cs |
56 Ba |
|
72 Hf |
73 Ta |
74 W |
75 Re |
76 Os |
77 Ir |
78 Pt |
79 Au |
80 Hg |
81 Tl |
82 Pb |
83 Bi |
84 Po |
85 At |
86 Rn |
87 Fr |
88 Ra |
|
104 Rf |
105 Db |
106 Sg |
107 Bh |
108 Hs |
109 Mt |
110 Ds |
111 Rg |
112 Cn |
113 Uut |
114 Uuq |
115 Uup |
116 Uuh |
117 Uus |
118 Uuo |
|
| positive impact |
| low toxicity |
| medium toxicity |
| heigh toxicity |
|
57 La |
58 Ce |
59 Pr |
60 Nd |
61 Pm |
62 Sm |
63 Eu |
64 Gd |
65 Tb |
66 Dy |
67 Ho |
68 Er |
69 Tm |
70 Yb |
71 Lu |
89 Ac |
90 Th |
91 Pa |
92 U |
93 Np |
94 Pu |
95 Am |
96 Cm |
97 Bk |
98 Cf |
99 Es |
100 Fm |
101 Md |
102 No |
103 Lr |