Patent ID: 9174861
Filing Date: 2015-11-03
Classification: C02F,C04B

Abstract:
1. A process of dissolving scale in a system for treating water with lime that is in the form of calcium hydroxide, that includes; (a) a lime mixing vessel in which lime and water are mixed to form a lime slurry; (b) a slurry holding tank for receiving lime slurry from the lime mixing vessel; and (c) a grit separation device for receiving lime slurry and separating grit particles therefrom; wherein each of the lime mixing vessel, slurry holding tank and grit separation device has a liquid level therein, wherein the process of dissolving scale dissolves scale on internal surfaces of each of the lime mixing vessel, slurry holding tank, and grit separation device, the process of dissolving scale comprising: adding an acid into the system; introducing water into at least one of the lime mixing vessel, slurry holding tank and grit separation device to provide an acid/water solution, wherein the acid/water solution is introduced into each of the lime mixing vessel, slurry holding tank and grit separation device, above their respective liquid levels, wherein the acid/water solution is introduced via spray nozzles in upper ends of each of the lime mixing vessel, slurry holding tank and grit separation device; and monitoring the level of scale buildup in at least one of the lime mixing vessel, the slurry holding and the grit separation device and initiating the scale dissolving process when scale buildup reaches a predetermined level, wherein the step of monitoring the scale buildup further comprises using one or more load cells to calculate the weight of scale and when a predetermined mass is reached, the scale dissolving process is triggered; the acid/water solution being pumped at varying pressures to scour the internal surfaces to remove lime scale.