Abstract: The invention provides a method of extending the useful life of high temperature heat exchangers, e.g., reactor feed/effluent heat exchangers, in installations where the heat exchanger is contacted by a process fluid stream, e.g., a feedstock comprising ethylbenzene at a temperature where the process stream may cause deterioration of contacted metal surfaces of the heat exchanger and/or undergo catalytic reaction as a result of contact with the contacted metal surfaces. The new method comprises the step of mechanically removing material from those surfaces of the heat exchanger that are to be contacted by the process fluid stream, so as to render said surfaces less susceptible to attack from said high temperature process fluid stream.

Abstract: The invention provides a method of extending the useful life of high temperature heat exchangers, e.g., reactor feed/effluent heat exchangers, in installations where the heat exchanger is contacted by a process fluid stream, e.g., a feedstock comprising ethylbenzene, at a temperature where the process stream may cause deterioration of contacted metal surfaces of the heat exchanger and/or undergo catalytic reaction as a result of contact with the contacted metal surfaces. The new method comprises the step of mechanically removing material from those surfaces of the heat exchanger that are to be contacted by the process fluid stream, so as to render said surfaces less susceptible to attack from said high temperature process fluid stream.

Abstract: In the preheating of a liquid reaction mass of polyolefin dissolved in liquid olefin monomer by passing it through a multiple pass preheater, the improvement of using generally U-shaped heat exchanger tubes in a generally U-shaped shell.