1
catalysts for use in the industries of manufacture of industrial chemicals, oil processing, petroleum refining, coal refining, desulphurization of petroleum fractions, catalytic pollution control of flue gases, stack gases and exhaust gases, and/or catalytic purification of flue gases, stack gases and exhaust gases
37
Installation and maintenance of catalytic emission control apparatus for the industries of manufacture of industrial chemicals, oil processing, petroleum refining or coal refining, desulphurization of petroleum fractions, catalytic pollution control of flue gases, stack gases and exhaust gases, and/or catalytic purification of flue gases, stack gases and exhaust gases
42
Designing of catalytic emission control apparatus for the industries of manufacture of industrial chemicals, oil processing, petroleum refining or coal refining, desulphurization of petroleum fractions, catalytic pollution control of flue gases, stack gases and exhaust gases, and/or catalytic purification of flue gases, stack gases and exhaust gases