JPH10153533A - Condensed liquid sampling apparatus, and condensed liquid sampling method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sample a condensed liquid at a clear condensation ratio by a method wherein process steam is introduced into a pressure container for a fixed period of time, a part thereof is condensed to determine the amount of a liquid and non-condensed steam is sufficiently cooled by a cooler to determine the amount of the condensed liquid. SOLUTION: With pressure adjusting valves V1-V3 closed, the apparatus is connected to a steam sampling line and the pressure adjusting valves V1 and V2 are gradually opened to adjust an internal pressure of a pressure proof container A. The pressure adjusting valve V3 is opened and then, closed after checking the discharging of the condensed water into the pressure proof container A. Processed steam is made to pass through the pressure proof container A for a specified time length, while the steam is cooled by a cooler C1 to measure the amount of the liquid L1. After a specified time passes, the pressure adjusting valves V1 and V2 are closed to measure a condensed liquid L2 accumulated in the pressure proof container A from the pressure adjusting valve V3 and a condensation rate is determined based on the amounts of the liquids L1 and L2. This measurement is repeated by varying the internal pressure of the pressureproof container A adjusting the pressure adjusting valves V1 and V2. This enables sampling of condensed liquids with different condensation ratios.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process (step) in which a part or all of steam can be condensed, and a condensate sampling for monitoring a corrosion accompanying the condensate during the condensation process and examining a condensation behavior. The present invention relates to an apparatus and a method for sampling condensed water in a steam generator of a boiler or a petrochemical plant using the apparatus.

[0002]

2. Description of the Related Art In a steam generator of a boiler, an acidic substance resulting from the incorporation of carbon dioxide gas is contained in steam. In a steam generator of a petrochemical plant, the recovered water of the process is used, so that during the decomposition of the process, Impurities such as generated organic acids or ammonia are contained in the steam.
When a part of the steam is condensed in the pipe of the steam generator, such contaminants are dissolved in the condensed water, which causes a problem such as corrosion. Therefore, in order to suppress corrosion due to an acid component, a measure such as adding a basic component such as a neutralizing amine is generally taken. It is extremely important for the safety management of the steam generator to confirm the degree of corrosion by the acid component and to confirm whether or not the basic component added as a countermeasure against corrosion is involved in the original corrosion inhibiting action. In particular, when the condensation rate, which is called the initial condensation, is about 1% or less, a very small amount of the condensate dissolves a large amount of the acid component and the basic component. Is in a completely different and extremely harsh environment. Therefore, in the steam generator, the condensation rate is 10%.
Even if countermeasures against corrosion were taken with the condensate having become 0%, it could not be said to be accurate in the initial condensate region.

[0003] A typical example in which initial condensation is a problem is acid corrosion occurring at the top piping of a crude oil atmospheric distillation column. The atmospheric distillation column has a multi-component hydrocarbon component having a different boiling point. Is collected, and the steam is introduced into an appropriate device,
By cooling from the outside and keeping the corresponding condensation temperature,
The initial condensation environment can be reproduced, a condensate having an arbitrary condensation rate can be collected, and a corrosion monitoring device or the like can be installed to check the corrosion state (for example, Japanese Patent Laid-Open No. 2-3024).
No. 95).

However, in a steam generator of a boiler or a petrochemical plant or the like, the process fluid is substantially a single component, and a small amount of impurities such as an acid component exists therein. In the case of a substantially single component, saturated steam has a constant boiling point under a constant pressure condition and transitions from a vapor state to a liquid state without a temperature change, so that the steam temperature is simply changed by the degree of external cooling. It is impossible.
When the initial condensation corrosion analysis apparatus for the top of the atmospheric distillation column was used, the condensation rate was unknown, and it was a fact that satisfactory data analysis was not possible.

[0005]

SUMMARY OF THE INVENTION The present invention makes it possible to collect a condensate exhibiting a definite condensing rate in a condensing section, particularly an initial condensing section, of a vapor system consisting of such a substantially single component and to analyze the condensed liquid. A condensate sampling apparatus capable of clarifying the cause of corrosion and further confirming the corrosion suppression effect by applying a neutralizing agent, and a method for sampling a condensate in a process vapor condensing section using the apparatus. With the goal.

[0006]

SUMMARY OF THE INVENTION The inventor of the present invention intends to develop a sampling apparatus which meets the above-mentioned purpose with the intention of sampling a condensate in a condensing section from a vapor system consisting of a substantially single component and analyzing the condensate. The present invention has been accomplished.

[0007] That is, the invention of claim 1 is a condensate sampling apparatus comprising a pressure-resistant container provided with at least a vapor inlet pipe, a condensate outlet pipe, and a vapor discharge pipe, for introducing process sample vapor into the pressure-resistant vessel. The vapor introduction pipe communicates with the inside of the pressure vessel via a pressure regulating valve, the tip of which extends to the upper space in the pressure vessel, the condensate taking-out pipe comes out from the bottom of the pressure vessel, and an open / close valve, Further, a means for collecting the condensate through a cooler for cooling the condensate is further provided, and a steam discharge pipe is protruded from the upper part of the pressure-resistant container, and a pressure regulating valve is further provided, and steam is further provided further. A condensate sampling device comprising means for collecting vapor condensed through a cooler for cooling the condensate.

According to a second aspect of the present invention, a pressure gauge is provided between the pressure adjusting valve of the steam inlet pipe and the steam inlet on the process side (that is, further from the pressure adjusting valve to the process side further). And / or a thermometer and between the pressure vessel and the pressure regulating valve of the steam discharge pipe (ie
This is a condensate sampling device equipped with a pressure gauge and / or a thermometer (on the pressure-resistant container side before the pressure regulating valve attached to the vapor discharge pipe).

According to a third aspect of the present invention, the distal end portion of the steam introduction pipe extending to the upper space in the pressure vessel is 5 to 45 degrees below the vertical.
3. The condensate sampling device according to claim 1, wherein the condensate sampling device is bent at an angle of degrees.

Further, the inventions of claims 4 and 5 are based on claim 1,
A method for sampling a condensate of a steam generator and a condensate of a boiler condenser related to an ethylene process cracking furnace using the condensate sampling device according to 2 or 3.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The condensate sampling apparatus according to the present invention guides process steam to a pressure vessel and adjusts the pressure in the pressure vessel to be smaller than that of the process system to condense a part of the steam. The container becomes a reservoir for condensate. The pressure is adjusted by a pressure adjustment valve attached to the steam introduction pipe and a pressure adjustment valve attached to the steam discharge pipe. For this pressure adjustment, a pressure gauge (or thermometer) attached to the process side further from the pressure adjustment valve of the steam introduction pipe indicates the pressure (or temperature) of the process, and the pressure of the steam discharge pipe from the pressure-resistant vessel is increased. A pressure gauge (or thermometer) attached to the pressure vessel side before the pressure regulating valve indicates the pressure (or temperature) in the pressure vessel, so it can be used as a reference when adjusting the condensation rate of condensed water in the pressure vessel. .

[0013] The tip of the steam introduction pipe extending to the upper space in the pressure vessel is preferably installed at an angle of 5 to 45 degrees from the vertical. By forming an angle without directing the tip directly upward, the introduced steam is not directly discharged from the steam discharge pipe, but the introduced steam flows in a spiral shape along the wall of the pressure-resistant container, and the pressure is reduced. The inside of the container can be brought as uniform as possible.

The process vapor is led to a pressure vessel for a predetermined time,
A part of the steam is condensed in the vessel, and the non-condensed steam is discharged through a steam discharge pipe. At this time, the discharged steam is sufficiently cooled by a cooler attached to the end thereof, and is converted into a liquid state, and the amount of the discharged steam within the time is grasped by a liquid amount.
Collected in containers. On the other hand, the condensate condensed during this time is
The condensate is taken out from a condensate take-out tube attached to the bottom of the pressure-resistant container, cooled sufficiently by a cooler attached to the tube, and collected in a liquid state in the container. The condensing rate can be determined from the amount of liquid from the vapor discharged from the vapor discharge pipe during the time and the amount of liquid condensed in the container and discharged from the condensed liquid discharge pipe.

The pressure and temperature on the process side are determined by the process operating conditions. The pressure (or temperature) in the pressure vessel is adjusted by adjusting the pressure adjustment valve of the steam introduction pipe and the pressure adjustment valve of the steam discharge pipe. And consequently the rate of condensation of the process vapor can be varied.

Since the shape of the pressure vessel in the present invention is to collect condensed water, a vertically long cylindrical shape is practically more convenient. The size is not particularly limited, but it is sufficient if condensed water is obtained to the extent that analysis is possible, and the diameter is about 5 cm and the height is about 15 cm.

[0017]

【Example】

[Embodiment 1] An embodiment of a condensate sampling apparatus according to the present invention will be described with reference to FIG. In FIG. 1, (a) is a steam introduction line, (b) is a steam discharge line, (c) is a condensate removal line, A is a pressure-resistant vessel (condensate liquid reservoir), and V1 is an amount of steam introduced into the pressure-resistant vessel. Adjust the pressure regulating valve, V
2 is a pressure adjusting valve for adjusting the pressure in the pressure vessel, V3
Is an open / close valve used to take out condensate, P1 is a pressure gauge for measuring the pressure of the process steam, P2 is a pressure gauge for measuring the pressure in the pressure vessel, and C1 is for cooling the steam discharged from the pressure vessel. A cooler, C2 is a cooler for cooling the condensed liquid, L1 is a liquid amount obtained by condensing steam discharged from the pressure-resistant container, and L2 is a condensed liquid amount. The tip of the steam introduction pipe extending to the upper space in the pressure vessel is 3
It was installed at an angle of 0 degrees. The outer peripheral surface of the pressure vessel and the steam introduction line leading to the pressure vessel were covered with a heat insulating material.

Condensate sampling method: The condensate was collected by the following operation in the apparatus shown in FIG. 1) V1, V2, and V3 were closed, and the apparatus was connected to the steam collection line. 2) While V3 was closed, V1 and V2 were gradually opened to adjust the pressure in the pressure-resistant container. 3) V3 was opened, and after confirming that no condensed water was present in the pressure-resistant container, V3 was closed. 4) From the time when V3 was closed, process steam was passed through the pressure vessel for a predetermined time, the steam during that time was cooled by C1, and the liquid amount L1 was measured. 5) After a lapse of a predetermined time, V1 and V2 were closed, and the condensate L2 accumulated in the pressure-resistant container was measured from V3. 6) The calculation of the condensation rate can be performed by the following equation. Condensation rate (%) = {L2 / (L1 + L2)} × 100 7) Similarly, V1 and V2 were adjusted to change the pressure in the pressure-resistant container (by changing the condensation rate), and the above operations 2 to 6 were repeated. .

[Embodiment 2] In a steam generator (steam generator) for generating diluted steam in a naphtha cracking furnace of an ethylene plant, steam from the naphtha cracking furnace is recovered and reused for steam generation. Organic acids such as acetic acid, formic acid, and propionic acid generated during decomposition, and ammonia and the like are present in the system. When a part of the steam is condensed in the pipe, these contaminants dissolve in a small amount of condensed water and cause corrosion. As a countermeasure, a neutralizing amine is usually added. As a means for evaluating the effect of the neutralizing amine, the condensate was sampled using the condensate sampling apparatus of the present invention, and analyzed. FIG. 2 shows the result of examining the relationship between the condensation rate and the pH of the condensed water. When a neutralizing amine is not used, the condensation rate is 10
At 0% (when completely condensed), the pH is increased by neutralization with an alkaline substance such as ammonia present in the system,
It can be seen that in a place where the condensing rate is low (initial condensing area), ammonia cannot be dissolved in the condensed water at a high temperature, so that the pH becomes extremely low. On the other hand, by adding an appropriate neutralizing amine as a neutralizing agent, the compound was well dissolved in water even at a high temperature, so that it was possible to maintain a high pH even at a low condensation rate. In addition, by analyzing the condensed water with different condensation rates, it is possible to know the components contained in each condensed water,
It can be used to find the cause of corrosion. Through such a study, it was recognized that an appropriate neutralizing amine could be selected, which could contribute to the countermeasures against corrosion of the apparatus.

[0020]

By using the condensate sampling apparatus of the present invention, it is possible to sample the condensate when the condensate is different in the vapor system composed of substantially a single component, and to analyze the condensate from the analysis of the condensate. The cause can be clarified, and the corrosion inhibitory effect by applying the neutralizing agent can be confirmed. Corrosion countermeasures for the condensing part, especially for the initial condensing part, can be effectively performed, which greatly contributes to the maintenance of the steam generator.

[Brief description of the drawings]

FIG. 1 is a drawing illustrating a condensate sampling device of the present invention.

FIG. 2 is a drawing showing the results of examining the relationship between the condensation rate and the pH of condensed water as a means for evaluating the effect of adding a neutralizing amine when applied to a steam generator of a naphtha cracking furnace.

[Explanation of symbols]

 (A): Steam introduction line (B): Steam discharge line (C): Condensate extraction line A: Pressure-resistant container (condensate reservoir) V1: Pressure regulating valve V2: Pressure regulating valve V3: Open / close valve P1: Pressure Total P2: Pressure gauge C1: Cooler C2: Cooler L1: Condensate amount L2: Condensate amount

Claims (5)

[Claims] 1. A condensate sampling device comprising a pressure-resistant container provided with at least a steam inlet pipe, a condensate outlet pipe and a steam discharge pipe, wherein the steam inlet pipe for introducing process sample vapor into the pressure-resistant vessel is pressure-adjusted. The inside of the pressure vessel is communicated via a valve, the tip of which extends to the upper space inside the pressure vessel, the condensate discharge pipe comes out from the bottom of the pressure vessel, and the opening / closing valve is provided at the end, and the condensate is further provided at the end. A means for collecting condensate through a cooler for cooling is provided, and a steam discharge pipe extends from the upper part of the pressure-resistant container, and is further provided with a pressure regulating valve, and further a cooler for cooling steam. A condensate sampling device comprising a means for collecting vapor condensed through the condensate. 2. A pressure gauge and / or a thermometer between the pressure adjusting valve of the steam inlet pipe and the steam inlet on the process side, and a pressure gauge and / or a thermometer between the pressure regulating vessel and the pressure adjusting valve of the steam exhaust pipe. 2. The condensate sampling device according to claim 1, further comprising a thermometer. 3. The condensate sampling device according to claim 1, wherein a tip portion of the steam introduction pipe extending to an upper space in the pressure-resistant container is bent at an angle of 5 to 45 degrees from the vertical. 4. A method for sampling a condensate of a steam generator associated with an ethylene process cracking furnace, comprising using the condensate sampling device according to claim 1, 2 or 3. 5. A method for sampling a condensate of a boiler condenser using the condensate sampling device according to claim 1, 2 or 3.