Patent ID: 6162644
Filing Date: 2000-12-19
Classification: G01N,Y10T

Abstract:
A method for controlling and optimizing a xylene isomer separation and isomerization process using a near infrared analyzer system, comprising the steps of:(A) extracting samples at the upstream stage from a xylene separation unit process, the upstream stage from a para-xylene separation unit process, the upstream stage from a xylene isomerization process, the upper-side downstream stage of a C7 separation process, and the lower-side downstream stage of the C7 separation process, respectively;(B) collecting the extracted samples in a fast loop via feed lines, respectively;(C) carrying out a primary heat exchange in a primary heat exchange system for the samples fed from the fast loop by cooling water supplied from a cooling water line;(D) determining whether or not respective temperatures of the samples heat-exchanged in the primary heat exchange system are not more than a first predetermined temperature;(E) secondarily cooling the samples, which have been cooled to the first predetermined temperature or less, by a chiller included in a secondary cooling system;(F) determining whether or not respective temperatures of the samples cooled in the secondary cooling system are not more than a second predetermined temperature;(G) sequentially selecting the samples cooled to the second predetermined temperature or less by a stream selector, and determining which sample has been selected from the first to the fifth samples;(H) partially extracting the sequentially selected samples by desired amounts, respectively, while returning the remaining portions of the samples to step (A) via first return lines, the fast loop, and second return lines;(I) sequentially detecting the components of the samples each extracted by a desired amount, by use of a probe, and then sequentially returning the samples to a sample recovery line via a third feed return line;(J) sequentially analyzing the samples, detected by the probe, in a near infrared analyzer, in accordance with a near infrared spectroscopy, in terms of ethylbenzene conversion, benzene selectivity, xylene loss, catalyst activity, para-xylene equilibrium constant, ortho-xylene equilibrium constant, para-xylene yield, and ortho-xylene yield;(K) sending data, obtained after the analysis for the samples in the near infrared analyzer, to a distributed control system in an on-line manner;(L) sending data resulting from a processing for the analysis data in the distributed control system to a process computer;(M) outputting the data received in the process computer in the form of a signal easily recognizable by an operator;(N) recognizing the data, which is displayed by the process computer, by the operator, inputting a desired command value by the operator, based on his determination made after his recognition, to the distributed control system; and(O) determining the input command value, thereby controlling valves for the samples to be opened or closed.