JPS58151307A - Method for utilizing low pressure steam exhausted from sulfur recovering plant - Google Patents

Abstract

PURPOSE:To utilize the titled low pressure steam as steam for keeping warmth (heating) by mixing the low pressure steam with high pressure steam under control with an ejector to generate medium pressure steam. CONSTITUTION:Sulfur vapor is liquefied by cooling with cooling water circulating between a condenser 2 and a steam drum 3, and the heated cooling water is returned to the drum 3. Low pressure steam (about 2.5-3.7kg/cm<2>) exhausted from the drum 3 is introduced into an ejector 10 from the 2nd fluid inlet through a control valve 7, a pipe 9 and a check valve 8, and high pressure steam from a source 11 for generating high pressure steam is introduced from the 1st fluid inlet through the 1st pressure regulating valve 12 to generate medium pressure steam (about 3.3-4.9kg/cm<2>). The medium pressure steam is fed to a sulfur recovering apparatus through a line 15 as steam for keeping warmth (heating). A change in the amount of medium pressure steam used is compensated by forming a by-pass line 13 provided with the 2nd pressure regulating valve 14 whose working pressure is 0.1-0.5kg/cm<2> lower than that of the 1st valve 12 between the source 11 and the line 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for effectively utilizing low pressure steam discharged from a 98/fi sulfur recovery plant.

When recovering elemental sulfur by directly reducing sulfur oxides from flue gas desulfurization equipment or by Claus reaction with Fi or hydrogen sulfide, a sulfur condenser is installed downstream of the reduction reactor or Claus reactor. A method is adopted in which the sulfur vapor flowing out from one reactor is indirectly heat-exchanged with water and condensed into liquid sulfur. According to this method,
The cooling water supplied to the sulfur condenser.

Generally, it is emitted from a sulfur condenser in a gas/liquid mixed phase.
This is then sent to a steam drum.

Here, the vapor phase and the liquid phase are separated, and the sulfur condensate is stored together with the cooling water that is replenished from time to time.

By the way, in the sulfur recovery method described above, the conduits, pumps, and storage tanks that handle liquid sulfur, including the lower area of the sulfur condenser, are
It is necessary to maintain the temperature at about 150° C., and using steam for this heat retention or heating requires a constant amount of steam at all times. On the other hand, the amount of steam discharged from the steam drum mentioned above not only varies depending on the operating conditions of the equipment, but also the pressure varies from 2.5 to 3.7 #/cm", abs
(127 to 140°C), it is difficult to use it as heat-insulating or heating steam for conduits, pipes, storage tanks, etc. that handle liquid sulfur.

Conventionally, it is used for insulation or heating of parts that handle liquid sulfur.

High pressure steam from an external source is utilized.

The present invention proposes a method in which low-pressure steam, which is discharged from the steam drum of a sulfur recovery plant and which cannot be used effectively as it is, is mixed with high-pressure steam and used as a heat source to prevent liquid sulfur from solidifying. It is something to do.

Thus, the method of the present invention introduces high-pressure steam from a high-pressure steam source into the first fluid inlet of the ejector through the 1111 pressure valve, and introduces low-pressure steam discharged from the steam drum of the sulfur recovery plant into the first fluid inlet of the ejector. 2 is introduced into the fluid inlet to generate intermediate pressure steam, and the high pressure steam is introduced into the ejector t.
No9inno9s to the twin leading to the ejector exit side.

A 2nd vI4 pressure valve that operates at a pressure O-1-0-5kf/crn" lower than the first pressure regulating valve is provided, and while the amount of intermediate pressure steam generated from the ejector is adjusted by the first and 211th pressure valves, It consists of circulating pressurized steam to the sulfur recovery plant as heat-insulating and/or heating steam.

The present invention will be described in detail with reference to the accompanying drawings.

Sulfur vapor exiting a reactor 1, such as a sulfur oxide reduction reactor or a 2-us reactor, is fed to a sulfur condenser 2. The sulfur vapor indirectly exchanges heat with the cooling water trapped from the steam drum 3 in the condenser 2, and is cooled to the condensation temperature and condensed into liquid sulfur. This liquid sulfur is the capacitor 2
is introduced into a sulfur tank 4 from the lower part of the sulfur tank 5, and is supplied to a sulfur storage tank 6 via a sulfur tank 5.

On the other hand, the cooling water supplied to the sulfur condenser 2 is partially evaporated by heat exchange with sulfur vapor, and is supplied from the upper part of the condenser 2 to the steam drum 3 in a gas/liquid mixed phase state. In the steam drum 3, a vapor phase and a liquid phase are separated from each other, and the liquid phase is circulated to the condenser 2 as cooling water.

As already mentioned, the steam phase U2 recovered from the steam drum
, 5 to 3.7 k-f/Cm", abl low-pressure steam with a temperature of 127% even as saturated steam.
The temperature is ~140℃, and the amount of vapor varies depending on the operating conditions of the equipment, so the conduit handling liquid sulfur,
in! The reality is that it is difficult to use it for insulating or heating storage tanks, etc.

In the present invention, low-pressure steam discharged from the steam drum 3 is introduced into the second fluid inlet of the ejector IO through a line 9t- provided with a drum internal pressure control valve 7 and a check valve 8. High-pressure steam brought from the high-pressure steam generation source 11 is supplied to the first fluid (also referred to as driving fluid) inlet of the ejector 1o.
11!1 is introduced via the pressure valve 12, whereby medium pressure steam is generated from the ejector lO. Ejector lO
Of course, the design is such that the recovery rate of low-pressure steam is maximized. Medium-pressure steam generated from the ejector 10 flows into a line 15 and a cooling water heater 16 as shown in the figure.
．． Sulfur storage tank 6, sulfur pump 5, sulfur capacitor 2
ζO steam is used to reliably prevent solidification of liquid sulfur, typically 3.3 to 4.9 to 4.7 cm!
It must be maintained at a pressure of iba (135-150°C). This pressure is often applied to the ejector l
The amount of high pressure steam introduced into O as the first fluid can be maintained by adjusting with the first pressure regulating valve 12. However, when the consumption of intermediate pressure steam within the system increases, it is difficult to maintain the intermediate pressure steam at the above set pressure.

Accordingly, in the present invention, a line 13 is provided for injecting high pressure steam from the high pressure steam generation source 11 into the line 15, and this bypass line 13 also includes a 111th fi pressure valve 12 with a weight of 0.1 to 0.5 kg 7 cm. "A second pressure regulating valve 14 that operates at a low pressure is provided, and while the pressure of the intermediate pressure steam flowing through the line 15 is detected by the pressure transmitter PS, the pressure of the intermediate pressure steam is regulated as follows. That is, the first pressure regulating valve 12, the consumption of medium-pressure steam set at 3.3 to 4.9 kg/cmq abs in the system increases, and the pressure is 0.1 to 0.5 kt/cm compared to the set pressure. when it gets low.

#! upon receiving the electrical signal from pressure transmitter P8! 2M pressure valve 1
4 is activated and maintains the pressure of the intermediate pressure steam by introducing high pressure steam directly into line 15. Although this method detects the pressure of intermediate pressure steam to open and close the first and second pressure regulating valves, it is also possible to perform similar control by detecting temperature instead of pressure. However, in this case, the response speed is somewhat slower than when it is based on pressure.

As another method, the first and second pressure regulating valves t may each be self-bladed pressure control valves, and the 2-in-15 and the first and second pressure regulating valves may be connected to each other by a pressure pipe instead of a pressure transmitter.
It is also possible to adjust the pressure of medium-pressure steam t-5.

Note that when the consumption of medium-pressure steam is small and low-pressure steam is not sucked by the ejector 10, the check valve 8 prevents the medium-pressure steam from flowing backward, and the low-pressure steam from the steam drum 3 is passed through the relief valve. 16 is released outside the system.

According to the present invention, the low-pressure steam discharged from the steam drum of the #L yellow recovery plant, which could hardly be utilized in the past, can be
It can be used as medium-pressure steam for heat retention or heating, and therefore the consumption of high-pressure steam can be significantly reduced compared to the case where high-pressure steam alone is used to heat the system. Furthermore, the present invention can be used even if the amount of low pressure steam discharged from the steam drum varies.

The amount of medium-pressure steam necessary for heat retention or heating can always be secured, and the amount of medium-pressure steam can be adjusted according to the consumption amount, so there is an advantage that just the right amount of medium-pressure steam can be provided.

[Brief explanation of drawings]

The drawing is a flow sheet showing one embodiment of the present invention. l; reactor 2; sulfur condenser 3; steam drum 4; sulfur tank s; sulfur, truncate 6: sulfur storage tank 7: steam drum internal pressure control valve 8; check valve 10; ejector
11; High pressure steam generation source 12; First pressure regulating valve 14; Second PL pressure valve 16; Cooling water heater 17; Relief valve PS
;pressure transmitter

Claims (1)

[Claims]! , high-pressure steam coming from a high-pressure steam source is introduced into a first fluid inlet of the ejector through a first pressure regulating valve, and low-pressure steam discharged from a steam drum of the sulfur recovery plant is introduced into a second fluid inlet of the ejector. to generate medium pressure steam. A 1ii41 pressure regulating valve and a 0.
The second pressure regulating valve, which operates at a lower pressure of 1 to O-5 kt/cm, is activated to reduce the amount of intermediate pressure steam generated from the ejector to the first one.
A method of utilizing the low-pressure steam, which comprises depositing the intermediate-pressure steam as heat-retaining and/or heating steam in a sulfur recovery plant while using a second pressure regulating valve.