FEED SUPPLY UNIT

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.

Claims

1-15. (canceled)

16. 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).

17. The feed supply unit of claim 16, 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.

18. The feed supply unit of claim 16, 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.

19. A chemical production unit, said chemical production unit comprising a feed supply unit according to claim 16 and a reactor, wherein at least a part of the feed dosage device according to (a.i) is located inside the reactor.

20. The chemical production unit of claim 19, 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.

21. A method for operating the feed supply unit according to claim 16, 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).

22. The method of claim 21, 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).

23. The method of claim 21, wherein the viscosity unstable liquid feed is a solidifiable liquid feed.

24. The method of claim 23, wherein the solidifiable liquid feed comprises a dinitrotoluene.

25. The method of claim 21, 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).

26. The method of claim 21, 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.

27. Use of a feed supply unit according to claim 16 for improving the safety profile of the feeding of a viscosity unstable liquid feed to a reactor.

28. 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 16.

29. Use of a feed supply unit according to claim 16 for preventing the solidification of a viscosity unstable liquid feed being fed to a reactor via said feed supply unit.

30. A method for preventing the solidification of a viscosity unstable liquid feed, the method comprising employing a feed supply unit according to claim 16 for feeding said viscosity unstable liquid feed to a reactor.

Description

BRIEF DESCRIPTION OF THE FIGURE

[0178] The invention will now be further described by means of an example embodiment in view of a FIGURE.

[0179] FIG. 1: a schematic representation of a chemical production unit according to an example embodiment of the invention.

[0180] FIG. 1 shows an example embodiment of a chemical production unit according to the invention. This chemical production unit is comprised of a reactor 3 and a feed supply unit. The feed supply unit can be looked at as been comprised of a feed dosage unit, a flushing unit and signal lines 24 constituting signal transmission means. As it will be described later, these signal lines 24 connects parts of the feed dosage unit with a part of the flushing unit.

[0181] The feed dosage unit serves for supplying a viscosity unstable liquid feed into the reactor 3. This feed dosage unit comprises a feed dosage device 10, which can for example be a nozzle, being placed inside the reactor 3, a feed pump 2, a feed pipe 1 connecting the feed pump 2 with the feed dosage device 10, and a feed supply pipe 8 supplying the feed pump 2 with liquid feed. As can be seen, the feed supply pipe 8 comprises a valve 9 and the feed pipe 1 comprises two valves 1a, 1b. The feed pump 2 usually comprises a mechanical part and an electric motor.

[0182] In the example embodiment shown, the feed dosage unit further comprises three monitoring means 20, 21, 22 namely a valve monitoring means 20 monitoring the status of the valve 9 of the feed supply pipe 8, for example its open/close state, a motor of pump monitoring means 21, which in a simple case monitors the on/off state of the motor of the feed pump 2, and a feed pipe monitoring means 22. This feed pipe monitoring means 22 monitors for example the open/close states of the valves 1a, 1b of the feed pipe 1 and/ or the flow through the feed pipe 1.

[0183] The flushing unit comprises a flushing medium tank 4 having a pressurized gas inlet 5 and an inlet 6 for flushing medium. The flushing medium is in most cases de-ionized water. The pressure inside the flushing medium tank exceeds the pressure in the reactor 3. The flushing unit further comprises a flushing medium pipe 7 having a valve 9 forming a controllable flow through device. This flushing medium pipe 7 extends from the flushing medium tank 4 - usually its bottom - to the feed dosage unit, especially to its feed pipe 1. In the example embodiment shown, the flushing medium pipe ends between the two valves 1a, 1b of the feed pipe 1. Although this is not shown in the schematic representation of FIG. 1, the flushing medium tank 4 is usually substantially smaller than the reactor 3. A heating device can be provided inside the flushing medium tank 4 but is not shown in the FIGURE.

[0184] A control means 23 controls the controllable flow-through device 11 of the flushing medium pipe. In a simple case the controllable flow-through device 11 only has the states “open” and “closed”, such that the control means 23 can only make the controllable flow-through device 11 change between these two states. The control means 23 usually has an internal clock.

[0185] The afore-mentioned signal lines 24 transmit signals from the valve monitoring means 20, the motor of pump monitoring means 21, and the feed pipe monitoring means 22 to the control means 23.

[0186] Depending on the signals received from the monitoring means 20, 21, 22 the control means 23 opens the controllable flow-through device 11 such that a flushing process is started and flushing medium streams from the flushing medium tank 4 through the flushing medium pipe 7 and at least a section of the feed pipe 1 into the reactor 3. In the example embodiment shown, typical signals generated by be monitoring means that lead to a start of a flushing process are that the valve 9 changes its open/closed state and/ or the motor of the feed pump changed its on/off state. The duration of a flushing process can be controlled by the internal clock of the control means 23.

TABLE-US-00001 List of reference numbers in the FIGURE 1 feed pipe 1a,b valve in feed pipe 2 feed pump 3 reactor 4 flushing medium tank 5 pressurized gas inlet 6 inlet for flushing medium 7 flushing medium pipe 8 feed supply pipe 9 valve of feed supply pipe 10 feed dosage device 11 controllable flow-through device (valve of flushing medium pipe) 20 valve monitoring means 21 motor of pump monitoring means 22 feed pipe monitoring means 23 control means 24 signal lines