Patent GB-919326-A (GB)
Title: Measurement of x-ray absorption in fluid streams
Inventor: FORRESTER JOHN STANLEY
IPC: G01N23/12
Filed: 1961-07-17
Abstract: An X-ray absorption measuring apparatus for monitoring a fluid stream comprises a metal block having a passageway 23 for the fluid and upper and lower chambers which communicate with the passageway, the upper chamber accommodating a window 16 behind which a bolt 11 <PICT:0919326/III/1> <PICT:0919326/III/2> supports a monochromatic X-ray source 12 and the lower chamber accommodating a window 26 behind which a member 21 supports a Geiger tube 18, the bolt 11 and the member 21 each being arranged to engage and secure in position the associated window, suitable gaskets 24 and 25 being interposed for sealing purposes.  The X-ray source comprises Fe55 which is plated on a small piece of platinum which is fastened to bolt 11. The windows are made of beryllium and the block is formed of stainless steel or other corrosion resistant material.  The output of the Geiger tube may be applied to a counter circuit the result from which may be presented periodically by a printer.  For high count rates a rate meter may be provided.  For low count rates, a timer may be provided to record the time necessary to reach a predetermined count.  In one application of the invention, Fig. 3, the apparatus is employed to monitor the sulphur concentration in the output of a hydrofining process in which kerosene, gas oil residue or lube stocks supplied via line 101 together with hydrogen via line 103 is preheated in a furnace 102 by combustion of natural gas supplied via line 119 and then supplied to a reaction chamber 105 maintained at 550 DEG -800 DEG F. and 150-800 p.s.i.g., containing a cobalt molybdate on alumina catalyst.  The reactor effluent is withdrawn via line 106 and passed via a cooler 107 to a separator 108 from which gas and liquid are withdrawn via lines 110 and 111 respectively.  The gas is either released or recycled to a scrubber system to remove hydrogen sulphide and then supplied back to reactor 105.  The liquid is passed to a low pressure separator, which removes remaining residual gas, the liquid from the bottoms being passed via pump 123 to storage.  In applying the apparatus of the invention, a portion of either the gas or liquid output is passed via an X-ray monitor apparatus 112, 125 to determine the sulphur content.  The monitor may provide an electric or pneumatic signal 120, 128, which actuates a mechanism 113 to regulate the furnace firing rate by adjusting a valve 127 in fuel line 119.ALSO:<PICT:0919326/IV(a)/1> <PICT:0919326/IV(a)/2> An X-ray absorption measuring apparatus for monitoring a fluid stream comprises a metal block having a passageway 23 for the fluid and upper and lower chambers which communicate with the passageway, the upper chamber accommodating a window 16 behind which a bolt 11 supports a monochromatic X-ray source 12 and the lower chamber accommodating a window 26 behind which a member 21 supports a Geiger tube 18, the bolt 11 and the member 21 each being arranged to engage and secure in position the associated window, suitable gaskets 24 and 25 being interposed for sealing purposes. The X-ray source comprises Fe55 which is plated on a small piece of platinum which is fastened to bolt 11.  The windows are made of beryllium and the block is formed of stainless steel or other corrosion resistant material.  The output of the Geiger tube may be applied to a counter circuit the result from which may be presented periodically by a printer.  For high count rates a rate meter may be provided.  For low count rates, a timer may be provided to record the time necessary to reach a predetermined count.  In one application of the invention, the monitor apparatus is employed to determine the oxygen content of a butoxy or polybutadiene resin.  In Fig. 4, which shows apparatus for a batch process, the feed, which comprises a copolymer of butadiene and styrene together with an aromatic diluent in the case of butoxy resin, and butadiene and an aromatic diluent in the case of polybutadiene resin, is supplied to the reaction chamber 202 via line 201 together with air via line 203.  The reaction chamber may be operated at pressures from atmospheric up to 150 p.s.i.g. and at temperatures from 20 DEG  to 150 DEG C.  A portion of the batch in the reactor is continuously recycled via line 204 and pump 205 and an X-ray monitor apparatus 206 according to the invention where the oxygen content is measured and continuously recorded.  When the end point of the reaction is reached the air supply to the reactor is cut off either manually or automatically by a signal from the monitor.  Vent gases leaving the reactor via line 209 are also passed via an X-ray monitor apparatus 208 which provide an electric or pneumatic signal to regulate a valve 204 in the air feed to the reaction chamber.  In a generally similar apparatus for a continuous process, Fig. 5 (not shown), part of the product from the reactor is passed through an X-ray monitor apparatus where the oxygen content is determined and an electric or pneumatic signal produced to control a valve in the reaction chamber air inlet line.ALSO:<PICT:0919326/IV (b)/1> <PICT:0919326/IV (b)/2> An X-ray absorption measuring apparatus for monitoring a fluid stream comprises a metal block having a passageway 23 for the fluid and upper and lower chambers which communicate with the passageway, the upper chamber accommodating a window 16 behind which a bolt 11 supports a monochromatic X-ray source 12 and the lower chamber accommodating a window 26 behind which a member 21 supports a Geiger tube 18, the bolt 11 and the member 21 each being arranged to engage and secure in position the associated window, suitable gaskets 24 and 25 being interposed for sealing purposes.  The X-ray source comprises Fe55 which is plated on a small piece of platinum which is fastened to bolt 11. The windows are made of beryllium and the block is formed of stainless steel or other corrosion resistant material.  The output of the Geiger tube may be applied to a counter circuit the result from which may be presented periodically by a printer.  For high count rates a rate meter may be provided.  For low count rates, a timer may be provided to record the time necessary to reach a predetermined count.  In one application of the invention, Fig. 2, the apparatus is employed in a system for the liquid phase isomerization of naphtha hydrocarbons using a Friedel-Crafts catalyst to monitor the level of aluminium bromide catalyst in a fluid stream recycled from the output of the system to the reaction chamber.  A feed comprising hydrocarbons is supplied by line 50 to reaction chamber 55 which contains a bed of aluminium oxide, molybdenum oxide, silica gel, calcined bauxite or the like. Aluminium bromide is supplied initially via feed line 51 and thereafter mainly via line 75 by recycling the system output.  Hydrogen halide promoter sufficient to maintain a pressure of 5-200 p.s.i.g. is supplied initially via line 52 and thereafter mainly by recycling via line 68 the output from distillation tower 58 which receives the output of chamber 55. Isobutane is also recovered from the distillation tower and supplied to chamber 55 via line 68.  The output from the distillation tower is brought to the pressure of chamber 55 by compressor 62.  Reflux to the distillation tower is added through line 60.  Heat for the distillation operation is provided via line 59.  The bottoms from the tower pass through pressure reduction valve 64 into flash chamber 65 operated at 0-50 p.s.i.g. or lower pressures. The product is flashed overhead and conducted via condenser 80 to storage.  The bottoms in the flash zone contain aluminium bromide and are returned via pump 73 and line 75 to the reaction chamber 55.  In applying the apparatus of the invention, part of the recycle fluid is withdrawn via pipes 82 and 86 and passed via the X-ray monitor apparatus 84 to determine the concentration of aluminium bromide in the fluid.  The apparatus may provide an electric or pneumatic signal 88 which, in the event of the concentration falling below the level necessary to achieve reaction at high conversion levels, controls a valve 94 to admit fresh aluminium bromide.