US-12623196-B2 - Feed supply unit

US12623196B2US 12623196 B2US12623196 B2US 12623196B2US-12623196-B2

Abstract

A feed supply unit comprising (a) a feed dosage unit for supplying a viscosity unstable liquid feed to a reactor, (b) a flushing unit for flushing at least a part of the feed dosage unit according to (a) with a flushing medium, and (c) a signal transmission means for transmitting a signal from a monitoring means to a control means.

Inventors

Jonas Mattern
Johannes Buettner
Ruediger Fritz
Maximilian KOELLER

Assignees

BASF SE

Dates

Publication Date: 20260512
Application Date: 20210719
Priority Date: 20200720

Claims (13)

1 . A feed supply unit comprising (a) a feed dosage unit for supplying a viscosity unstable liquid feed to a reactor, and (b) a flushing unit for flushing at least a part of the feed dosage unit according to (a) with a flushing medium, wherein the feed dosage unit according to (a) comprises (a.i) a feed dosage device for dosing the feed into a chemical reactor; (a.ii) a feed pump located upstream of the feed dosage device according (a.i); (a.iii) a feed pipe connecting the feed pump according to (a.ii) and the feed dosage device according to (a.i); (a.iv) a feed supply pipe, located upstream of the feed pump according to (a.ii) and ending in the feed pump according to (a.ii); (a.v) monitoring means for monitoring at least one operating parameter of the feed dosage unit; wherein the flushing unit according to (b) comprises (b.i) a flushing medium tank and means for pressurizing the flushing medium tank; (b.ii) a flushing medium pipe comprising a controllable flow-through device for adjusting the flow rate of the flushing medium from the flushing medium tank according to (b.i) to the feed dosage unit according to (a) and connecting the flushing medium tank and at least one of the feed dosage device according to (a.i), the feed pump according to (a.ii), the feed pipe according to (a.iii), and the feed supply pipe according to (a.iv); (b.iii) control means for controlling the controllable flow-through device according to (b.ii) based on the at least one parameter monitored by the monitoring means according to (a.v); wherein the feed supply unit further comprises (c) signal transmission means for transmitting a signal from the monitoring means according to (a.v) to the control means according to (b.iii).
2 . The feed supply unit of claim 1 , wherein the feed supply pipe according to (a.iv) comprises a valve and wherein the monitoring means according to (a.v) comprise means for monitoring the status of the valve.
3 . The feed supply unit of claim 1 , wherein the feed pump according to (a.ii) comprises an electric motor and wherein the monitoring means according to (a.v) comprise means for monitoring at least one parameter of the electric motor.
4 . A chemical production unit, said chemical production unit comprising a feed supply unit according to claim 1 and a reactor, wherein at least a part of the feed dosage device according to (a.i) is located inside the reactor.
5 . The chemical production unit of claim 4 , wherein the volume of the flushing medium tank according to (b.i) is in the range of from 1 to 50% of the volume of the reactor.
6 . A method for operating the feed supply unit according to claim 1 , the method comprising (i) providing a viscosity unstable liquid feed; (ii) feeding the liquid feed according to (i) via the feed supply pipe according to (a.iv) through the feed pump according to (a.ii) to the feed dosage device according to (a.1) via the feed pipe according to (a.iii); (iii) monitoring the at least one operation parameter of the feed dosage unit according to (a) via the monitoring means according to (a.v) and transmitting a signal from the monitoring means according to (a.v) to the control means according to (b.iii) via the signal transmission means according to (c); (iv) starting a flushing process if at least one of the at least one operating parameter of the feed dosage unit according to (a) changes beyond a pre-defined threshold value, wherein said flushing process comprising flushing, for a period of time, at least one of the feed dosage device according to (a.i), the feed pump according to (a.ii), the feed pipe according to (a.iii), the feed supply pipe according to (a.iv) with a flushing medium contained in the pressurized flushing medium tank according to (b.i) via the flushing medium pipe according to (b.ii) by increasing the flow of the flushing medium through the flow-through device according to (b.ii).
7 . The method of claim 6 , wherein the flushing process according to (iv) further comprises reducing feeding the liquid feed to the feed dosage device according to (ii) wherein said reducing feeding is carried out simultaneously with or after flushing according to (iv).
8 . The method of claim 6 , wherein the viscosity unstable liquid feed is a solidifiable liquid feed.
9 . The method of claim 8 , wherein the solidifiable liquid feed comprises a dinitrotoluene.
10 . The method of claim 6 , wherein at least during the flushing process according to (iv), the temperature of the flushing medium in the flushing medium tank according to (b.i) is higher than the melting point of the viscosity unstable liquid feed at the pressure inside the feed dosage unit according to (a), wherein at least during the flushing process according to (iv), the temperature of the flushing medium is from 1 to 40 K higher than the melting point of the viscosity unstable liquid feed at the pressure inside the feed dosage unit according to (a).
11 . The method of claim 6 , the feed supply unit being comprised in a chemical production unit, the production unit further comprising a reactor, wherein at least a part of the feed dosage device according to (a.i) is located inside the reactor, wherein during the flushing process according to (iv), the volume of flushing medium from the flushing medium tank according to (b.i) used for the flushing process is in the range of from 0.1 to 1% of the reaction volume of the reactor.
12 . A method for improving the safety profile of the feeding of a viscosity unstable liquid feed to a reactor, the method comprising employing a feed supply unit according to claim 1 .
13 . A method for preventing the solidification of a viscosity unstable liquid feed, the method comprising employing a feed supply unit according to claim 1 for feeding said viscosity unstable liquid feed to a reactor.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a National stage application (under 35 U.S.C. § 371) of PCT/EP2021/070163, filed Jul. 19, 2021, which claims benefit of European Application No. 20186644.9, filed Jul. 20, 2020, both of which are incorporated herein by reference in their entirety. The present invention relates to a feed supply unit comprising (a) a feed dosage unit for supplying a viscosity unstable liquid feed to a reactor, (b) a flushing unit for flushing at least a part of the feed dosage unit according to (a) with a flushing medium, and (c) a signal transmission means for transmitting a signal from a monitoring means to a control means. The present invention further relates to a chemical production unit comprising such a feed supply unit, to a method for operating such a feed supply unit, to a use of such a feed supply unit, to a method for improving the safety profile of the feeding of a viscosity unstable liquid feed to a reactor using such a feed supply unit, and to a method for preventing the solidification of a viscosity unstable liquid feed by using such a feed supply unit. For example for the production of isocyanates such as diisocyanates, including, but not being restricted to, toluene diisocyanates which in turn may comprise one or more of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, it is known to supply, in the course of the overall process, a feed comprising nitroaromatic compounds to a reactor. For this supply, a feed dosage unit having a dosage device, a feed pump upstream of the dosage device and a feed pipe connecting the feed pump and the feed dosage device, is commonly used. Nitroaromatic compounds are often viscosity unstable and tend to solidification such that one or more plugs can establish in the feed dosage unit, especially in its feed pipe. Such a nitroaromatic plug can be a safety-related risk due to the possibility of an uncontrolled runaway reaction. Accumulation of nitroaromatics can lead to uncontrolled runaway reactions at higher temperatures. For example in WO 2012/123469 A1, it is suggested to unplug a feed dosage unit with hot water in case of predicted or unpredicted stop of the dosage, especially in a case of an unpredicted stop like, for instance, an overfilling of the reactor. It was therefore an object of the invention to provide improvements relating the safety of a feed supply unit and thus of a chemical production unit comprising such a feed supply unit. According to the present invention, means are provided that allow an automatic flushing of the feed supply unit. This reduces the risk of a human error and enhances the safety of the feed supply unit and a chemical production unit comprising such a feed supply unit. Therefore, the present invention relates to a feed supply unit comprising (a) a feed dosage unit for supplying a viscosity unstable liquid feed to a reactor, and(b) a flushing unit for flushing at least a part of the feed dosage unit according to (a) with a flushing medium, wherein the feed dosage unit according to (a) comprises (a.i) a feed dosage device for dosing the feed into a chemical reactor;(a.ii) a feed pump located upstream of the feed dosage device according (a.i);(a.iii) a feed pipe connecting the feed pump according to (a.ii) and the feed dosage device according to (a.i);(a.iv) a feed supply pipe, located upstream of the feed pump according to (a.ii) and ending in the feed pump according to (a.ii);(a.v) monitoring means for monitoring at least one operating parameter of the feed dosage unit; wherein the flushing unit according to (b) comprises (b.i) a flushing medium tank and means for pressurizing the flushing medium tank;(b.ii) a flushing medium pipe comprising a controllable flow-through device for adjusting the flow rate of the flushing medium from the flushing medium tank according to (b.i) to the feed dosage unit according to (a) and connecting the flushing medium tank and at least one of the feed dosage device according to (a.i),the feed pump according to (a.ii),the feed pipe according to (a.iii), andthe feed supply pipe according to (a.iv); (b.iii) control means for controlling the controllable flow-through device according to (b.ii) based on the at least one parameter monitored by the monitoring means according to (a.v); wherein the feed supply unit further comprises (c) a signal transmission means for transmitting a signal from the monitoring means according to (a.v) to the control means according to (b.iii). The control means according to (b.iii) for controlling the controllable flow-through device according to (b.ii) can automatically set the flow-through device according to (b.ii) from a throttled or closes state to a less throttled or open state if a parameter of the feed dosage unit according to (a) monitored by the monitoring means according to (a.v) changes in a way that could result from or that could result in a solidification of liquid in the feed dosage unit accord