The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 16, 1993
Filed:
Jun. 28, 1991
Regis Stana, Lakeland, FL (US);
Stephen W Hilakos, Valrico, FL (US);
IMC Fertilizer, Inc., Northbrook, IL (US);
Abstract
An improved automatic control system for controlling a phosphoric acid plant in order to maximize recovery of phosphoric acid which includes a programmable computer, a rock flow control and measurement device for controlling and measuring the rock mass flow rate, an acid flow control and measurement device for measuring and controlling the sulfuric acid feed rate, wherein the computer is programmed to calculate the total amount of sulfuric acid added to the reactor, calculate the total amount of rock added to the reactor, over the time interval, calculate a new sulfuric acid feed point to make excess sulfate resulting from reaction of incoming acid and rock to have a predetermined excess sulfate, wherein the predetermined excess sulfate causes the phosphoric acid plant to operate at the maximum efficiency, calculate a number of gallons of sulfuric acid to be added or subtracted to the reactor to correct the excess sulfate of material already in the reactor, and to generate control signals to cause said sulfuric acid feed rate to change which causes said number of gallons to be added or subtracted using a pulse and then decays to the new sulfuric acid set point.