Pre-assembled process module unit of an ethane cracker unit, containing: -a system for filtering and cooling of dried cracked gas, -a deethanizer distillation column and associated equipment for C2-/C3+ separation, -an acetylene hydrogenation system to remove acetylene within a C2 stream, -a fuel gas drum that stores fuel gas for cracker furnaces, and  -a system to regenerate dryers in a cracker installation

This chapter does not cover: millstones and grindstones of Chapter 68, machinery or appliances of ceramics (Chapter 69), laboratory glassware (heading 7017), articles of base metal of Chapters 73-76 or 78-81, electromechanical domestic appliances of heading 8509, or electromechanical hand tools of heading 8467. Note 2 (Parts): Subject to certain exceptions, parts which are suitable for use solely or principally with a particular kind of machine are classified with that machine; parts equally suitable for two or more machines are classified in heading 8409, 8431, 8448, 8466 or 8473 as appropriate. Note 3 (Composite machines): Composite machines consisting of two or more machines fitted together to form a whole and other machines designed to perform two or more complementary or alternative functions are classified according to the principal function. Note 4 (Multi-function machines): Where a machine or combination of machines performs successive different operations on material, it is classified by the function it performs last. Note 5 defines 'machine tools' for working any material by removal, for heading 8456-8465.

1. This Section does not cover: (a) transmission or conveyor belts or belting of plastics of Chapter 39, or of vulcanised rubber (heading 4010), or other articles of vulcanised rubber other than hard rubber, for technical uses (heading 4016); (b) articles of leather or of composition leather (heading 4205) or of furskin (heading 4303), of a kind used in machinery or mechanical appliances or for other technical uses; (c) bobbins, spools, cops, cones, cores, reels or similar supports, of any material (for example, Chapter 39, 40, 44 or Section XV); (d) perforated cards for Jacquard or similar machines (for example, Chapter 39 or 48 or Section XV); (e) transmission or conveyor belts or belting of textile material (heading 5910) or other articles of textile material for technical uses (heading 5911); (f) precious or semi-precious stones (natural, synthetic or reconstructed) of headings 7102 to 7104, or articles wholly of such stones of heading 7116, except unmounted worked sapphires and diamonds for styli (heading 8522); (g) parts of general use, as defined in Note 2 to Section XV, of base metal (Section XV) or similar goods of plastics (Chapter 39); (h) drill pipe (heading 7304); (ij) endless bands of metal wire or strip (Section XV); (k) articles of Chapter 82 or 83; (l) articles of Section XVII; (m) articles of Chapter 90; (n) clocks, watches or other articles of Chapter 91; (o) interchangeable tools of heading 8207 or brushes of a kind used as parts of machines (heading 9603); similar interchangeable tools are to be classified according to the constituent material of their working part; (p) articles of Chapter 95; (q) typewriter or similar ribbons, whether or not on spools or in cartridges (heading 9612), or monopods, bipods, tripods and similar articles of heading 9620. 2. Subject to Note 1 to this Section, Note 1 to Chapter 84 and Note 1 to Chapter 85, parts of machines (not being parts of the articles of heading 8484, 8544, 8545, 8546 or 8547) are to be classified according to the following rules: (a) parts which are goods included in any of the headings of Chapter 84 or 85 (other than headings 8409, 8431, 8448, 8466, 8473, 8487, 8503, 8522, 8529, 8538 and 8548) are in all cases to be classified in their respective headings; (b) other parts, if suitable for use solely or principally with a particular kind of machine, or with a number of machines of the same heading, are to be classified with the machines of that kind or in heading 8409, 8431, 8448, 8466, 8473, 8503, 8522, 8529 or 8538 as appropriate; however, parts which are equally suitable for use principally with the goods of headings 8517 and 8525 to 8528 are to be classified in heading 8517; (c) all other parts are to be classified in heading 8409, 8431, 8448, 8466, 8473, 8503, 8522, 8529 or 8538 as appropriate or, failing that, in heading 8487 or 8548. 3. Unless the context otherwise requires, composite machines consisting of two or more machines fitted together to form a whole and other machines designed for the purpose of performing two or more complementary or alternative functions are to be classified as if consisting only of that component or as being that machine which performs the principal function. 4. Where a machine (including a combination of machines) consists of individual components (whether separate or interconnected by piping, by transmission devices, by electric cables or by other devices) intended to contribute together to a clearly defined function covered by one of the headings in Chapter 84 or Chapter 85, then the whole is to be classified in the heading appropriate to that function. 5. For the purposes of these Notes, the expression 'machine' means any machine, machinery, plant, equipment, apparatus or appliance cited in the headings of Chapter 84 or 85.