ES369036A1 - Gas cooling apparatus and process - Google Patents

Abstract

A heat exchanger comprises a housing structure 31 having therein a tubular central passage 30 in which a hot fluid is cooled through the passage wall by surrounding cooling means (e.g. tubes, or as shown, a coolant jacket 40), and a hot fluid inlet tube 38 extending into the passage 30 and having its discharge end formed as a diffuser nozzle 39 with an angle of divergence of from 4 to 10 degrees. The discharge end of the passage 30 may also be formed as a diffuser nozzle e.g. 47, with an angle of divergence of from 4 to 10 degrees. The heat exchanger is intended for the rapid cooling of reaction products from a hydrocarbon cracking process the coolant being water which enters the jacket through an inlet 45 and is discharged as steam through an outlet 46. In the plant described (Fig. 1), the generated steam is collected in a drum (32) and is discharged therefrom through a line (35) for heating or power purposes. Saturated water from the drum is ducted into the chamber 40 of the heat exchanger and constitutes the coolant for the hot fluid therein. As shown, the hot fluid inlet tube 38 is secured at one end only to the housing structure so that its other end may expand freely in the passage 30. Similarly the nozzle member 47 is secured at one end only to the housing structure thus permitting expansion relative to the cooledfluid discharge member 60. This latter may be secured to the fluid outlet line 37 either directly (as shown) or through an expansion joint. A narrow annular passage 56 or 60 is formed around by the housing structure around the free ends of the inlet tube 38 and discharge tube and a steam pressure higher than that of the hot fluid in passage 30, is maintained in these narrow passages to prevent leakage through these zones of the hot fluid. This is said to reduce thermal stresses. The sealing steam is supplied to the passages 56 and 60 from chambers 41, 42 respectively.