Heat Exchangers COMPACT HEAT EXCHANGERS （热交换器紧凑热交换器）.pdfVIP

Heat Exchangers COMPACT HEAT EXCHANGERS — PART 1: DDeessiiggnniinngg Plate-and-Frame Heat Exchangers Christopher Haslego, Alfa Laval Use these design charts for preliminary sizing. Graham Polley, onsidering available heat exchanger technolo- ed metal plates fitted between a thick, carbon-steel frame. gies at the outset of process design (at the Each plate flow channel is sealed with a gasket, a weld or process synthesis stage) is not general prac- an alternating combination of the two. It is not uncommon C tice. In fact, procedures established in some for plate-and-frame heat exchangers to have overall heat- companies preclude it. For instance, some purchasing de- transfer coefficients that are three to four times those found partments’ “nightmare” is having to deal with a single sup- in shell-and-tube heat exchangers. plier — instead they want a general specification that can This three-part series outlines the lost opportunities and be sent to all equipment vendors, in the mistaken belief the importance of proper heat exchanger selection. This arti- that they are then operating on a “level playing field.” cle discusses some general aspects of plate-and-frame heat This omission is both unfortunate and costly. It results in unnecessary cap- ital expenditure and in reduced energy efficiency. It also hinders the develop- ment of energy saving technology. Pinch analysis is the key tool used by engineers to develop flowsheets of ener- gy-intensive processes, where heat ex- changer selection is particularly impor- tant. Yet, this tool is hindering the adop- tion of a more-progres