Method for clearing shell side scale of shell and tube heater in monoammonium phosphate production on line

Abstract

The invention discloses a method for clearing shell side scale of a shell and tube heater in monoammonium phosphate production on line, which comprises: (1) preparing cleaning solution consisting of 20 to 40 percent of phosphoric acid (in form of P2O5), 30 to 40 percent of nitric acid, 60 to 98 percent of sulfuric acid and 10 to 15 percent of fluosilicic acid in a mass ratio of 5:3:1:1; (2) placing a container serving as a cleaning circulating tank and a conveying pump connected with a cleaning solution outlet pipe on a mobile cart, moving the mobile cart toward the shell and tube heater of which the scale is to be cleared, connecting the conveying pump with an acid inlet at the lower part of the shell side of the heater and connecting the acid outlet on the upper part of the shell side of the heater with the container by a conduit; and (3) starting the conveying pump during the periodical stop of the device, feeding the cleaning solution the shell side of the heater to clean the shell side of the heater circularly, and introducing low-pressure steam from the bottom of the heater for heating. In the method, the online scale clearing can be realized flexibly without detaching the heater and with small investment; the equipment configuration is simple; the scale are cleared obviously; and cleaning is performed once a year. The method is applicable for monoammonium phosphate manufacturers.

Description

【Technical field】 [0001] The invention relates to the production of phosphate fertilizer, and furthermore, to the production of ammonium phosphate, in particular, to a method for removing fouling on the shell side of a shell-and-tube heater in the production of ammonium phosphate. 【Background technique】 [0002] Ammonium phosphate fertilizers include monoammonium phosphate and diammonium phosphate, which are one of the main fertilizers in modern agriculture and forestry industries. Ammonium phosphate fertilizers are usually produced by the "conventional" or "neutralized slurry thickened" method. Since phosphate rock contains a large amount of Ca, Mg, Al, SiO 2 A large number of impurities, such as ammonium phosphate slurry, in the concentration process, there is a layer of scaling on the surface of the shell side (that is, between the tubes) of the tubular heater, which affects the heat transfer efficiency of the heater. In order to remove scale, the traditional method is ...

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Problems solved by technology

[0003] The purpose of the present invention is to provide an online method for removing fouling on the shell side of the tubular heater in the production of ammonium phosphate, so as to solve the problem of removing fouling on the shell side of the heater

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