1. An apparatus (10) for the processing of substantially planar workpieces (14), which can be moved in a transport plane (34) relatively to the apparatus (10), the apparatus containing at least one grinding head (18a, 18b, 18c, 18d) with a tool carrier (20) rotatable around a carrier axis (22) which is orthogonal with respect to the transport plane (34) and with several grinding brushes (24, 40, 46) drivable by a planetary gear drive and containing a brush body (30, 44, 50) and bristles attached thereto (32, 42, 48) being mounted to the tool carrier so that they can be rotated individually around their individual brush axes (26) which are orthogonal with respect to the transport plane (34), wherein the ends of the bristles (32, 42, 48) of each single grinding brush (24, 40, 46) are arranged at various distances to the transport plane (34).
2. An apparatus (10) according to claim 1, further characterized in that the bristles (32) of each single grinding brush (24) differ in length.
3. An apparatus (10) according to claim 1 or 2, further characterized in that the brush bodies (44) are tilted with respect to the transport plane (34).
4. An apparatus (10) according to claim 1, further characterized in that the distances between the ends of the bristles and the transport plane (34) differ by 1 to 2 cm.
5. An apparatus (10) according to claim 1, further characterized in that the apparatus contains several grinding heads (18a, 18b, 18c, 18d) which are arranged in two rows extending transversely to the transport direction of the workpiece (14), which rows are arranged one behind the other in the feed direction (16) of the workpiece (14) with the two rows of grinding heads being offset to each other in a direction transversely to the transport direction (16) of the workpieces (14) in such a manner that the grinding heads (18b resp. 18c) of one row\u2014when viewed in the transport direction (16) of the workpiece (14)\u2014close the gaps between the grinding heads (18c, 18d resp. 18a, 18b).
6. An apparatus according to claim 1, further characterized in that the bristles of at least one of the grinding brushes differ from the bristles of the other grinding brushes in at least one of the their material characteristics, structure, texture, hardness, thickness and trimming length.
7. An apparatus according to claim 1, further characterized in that the infeed of at least some of the grinding brushes can be adjusted individually.
8. An apparatus according to claim 1, further characterized in that the infeed can be adjusted for sets of grinding brushes of the same type.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1-5. (canceled)
6. A process for preparing 3-pentenenitrile by hydrocyanating 1,3-butadiene, which comprises the following process steps:
(b\u2032) distillation of 1,3-butadiene comprising water, 1- and 2-butenes and a stabilizer in a distillation apparatus K4 to obtain a stream 15 as the bottom product, which comprises dried 1,3-butadiene, 1- and 2-butenes and the stabilizer, and a stream 16 as the top product, which comprises an azeotropic 1,3-butadienewater mixture, condensation of the stream 16 in a condenser W, transfer of the resulting condensate (stream 17) into a phase separation apparatus, recycling of the upper liquid phase (stream 18) consisting of 1,3-butadiene as reflux to the column K4, and discharge of the lower liquid aqueous phase (stream 19),
(a) reaction of stream 15 in a reactor R1 with hydrogen cyanide over at least one catalyst (stream 6d) to obtain a stream 1 which comprises 3-pentenenitrile, 2-methyl-3-butenenitrile, the at least one catalyst in the form of homogeneously dissolved nickel complexes or nickel(0) complexes and phosphorus ligands, unconverted 1,3-butadiene, and 1- and 2-butenes, with or without residues of unconverted hydrogen cyanide,
(b) distillation of stream 1 in a distillation apparatus K1 to obtain a stream 2 as the top product, which comprises the predominant portion of the 1,3-butadiene from stream 1, and to obtain a stream 3 as the bottom product, which comprises 3-pentenenitrile, the at least one catalyst, 2-methyl-3-butenenitrile, 1- and 2-butenes and the remaining proportion of the 1,3-butadiene from stream 1 which has not been removed in stream 2,
(c) distillation of stream 3 in a distillation apparatus K2 to obtain a stream 5 at a side draw of the column, which 3-pentenenitrile and 2-methyl-3-butenertitrile, a stream 6 as the bottom product, which comprises the at least one catalyst, and a stream 4 as the top product,
(d) compression of stream 4 in the compressor V1, discharge of a gaseous substream 4b which comprises 1- and 2-butenes, transfer of the compressed stream 4a into the condenser W1, combined cond. With stream 2 from b) in combined condensation of this stream 2 from b) and transfer of the condensate as stream 9, partly as reflux to the column K1 (stream 9b), partly as return stream into the reactor R1 (stream 9a), and
(e) distillative separation of stream S to obtain 3-pentenenitrile and 2-methyl-3-butenenitrile.
7. A process for preparing 3-pentenenitrile by hydrocyanating 1,3-butadiene, which comprises the following process steps:
(a) reaction of dried 1,3-butadiene, which is passed as stream 14 from a side draw of column K1 into reactor R1, with hydrogen cyanide over at least one catalyst to obtain a stream 1 which comprises 3-pentenenitrile; 2-methyl-3-butenenitrile, the at least one catalyst in the form of homogeneously dissolved nickel complexes or nickel(0) complexes and phosphorus ligands, 1,3-butadiene, and 1- and 2-butenes, with or without residues of unconverted hydrogen cyanide,
(b) distillation of stream 1 in a distillation apparatus K1 by feeding 1,3-butadiene comprising water, 1- and 2-butenes and a stabilizer in the region between top and side draw of the column to obtain a stream 2 as the top product, stream 14 as the side draw and a stream 3 as the bottom product which comprises 3-pentenenitrile, the at least one catalyst, 2-methyl-3-butenenitrile and the remaining portion of the 1,3-butadiene from stream 1 which has not been removed in stream 2,
(c) distillation of stream 3 in a distillation apparatus K2 to obtain a stream 4 as the top product, which 1,3-butadiene and 1- and 2-butenes, a stream 6 at a side draw of the column, which 3-pentenenitrile and 2-methyl-3-butenenitrile, and a stream 6 as the bottom product, which comprises the at least one catalyst,
(d) condensation of stream 2 from distillation apparatus K1 and the stream 4a which has been compressed in one compressor V1 or a plurality of compressors from distillation apparatus K2 into a condenser W1 or a plurality of condensers, transfer of the resulting condensate as stream 9 into a phase separation apparatus, transfer of the upper liquid phase consisting of 1,3-butadiene as stream 11 to the top of the distillation apparatus K1, and discharge of the lower liquid aqueous phase as stream 12, and
(e) distillative separation of stream 5 to obtain 3-pentenenitrile and 2-methyl-3-butenenitrile.
8. The process according to claim 6, wherein, in process step (d), an aqueous solution of at least one butadiene stabilizer is introduced into the compressor(s) andor condenser(s).
9. The process according to claim 7, wherein, in process step (d), an aqueous solution of at least one butadiene stabilizer is introduced into the compressor(s) andor condenser(s).
10. The process according to claim 6, wherein a substream 6a which comprises the at least one catalyst and at least one butadiene stabilizer is discharged from stream 6.
11. The process according to claim 7, wherein a substream 6a which comprises the at least one catalyst and at least one butadiene stabilizer is discharged from stream 6.
12. The process according to claim 8, wherein a substream 6a which comprises the at least one catalyst and at least one butadiene stabilizer is discharged from stream 6.
13. The process according to claim 6, wherein unconverted hydrogen cyanide is discharged from the phase separation apparatus with stream 19.
14. The process according to claim 7, wherein unconverted hydrogen cyanide is discharged from the phase separation apparatus with stream 12.