Detection system for leakage of regeneration gas heater

Abstract

The utility model discloses a system for detecting the leakage of a regeneration gas heater, which is used for solving the technical problem of how to eliminate whether the regeneration of a drying tower is not thorough due to the leakage of the regeneration gas heater, and belongs to the technical field of coke oven gas. The device comprises a regeneration gas heater, a heat exchanger and a DCS (Distributed Control System), a process gas side inlet of the regeneration gas heater is connected with a cold blowing drying tower, a heated process gas outlet is connected with a regeneration drying tower, a heat source side inlet of the regeneration gas heater is connected with a medium-pressure superheated steam pipe network, and a heat source side outlet of the regeneration gas heater is connected with a gas-liquid separator; a part of heated process gas is led out from a process gas inlet of the heat exchanger through a pressure guide pipe, a process gas outlet of the heat exchanger is connected with a torch, a water dew point measuring instrument is connected between the heat exchanger and the torch, and the water dew point measuring instrument is connected into a DCS (Distributed Control System).

Description

TECHNICAL FIELD

[0001] The utility model belongs to the coke oven gas technical field, especially relates to a detection system about the leakage of regenerative gas heater. BACKGROUND

[0002] China is the world's largest coke producer, coke oven gas is a byproduct of coking industry, its main components are oxygen (volume fraction 55-60%) and methane (23-27%). Producing 1 ton of coke about byproduct 200-250 cubic meters of coke oven gas. China's annual supply of comprehensive utilization of coke oven gas up to 800-1000 billion square, the heat value is equivalent to the total of two lines of west-east gas transmission, has higher utilization value. Because the CH, CO, CO, C2 content in coke oven gas is nearly 40%, the hydrogen content is high, therefore coke oven gas can make most of CO, CO, etc. convert into CH4 by methanation reaction, obtain the mixed gas containing H, CH, N, water mainly, then adopt cryogenic separation to obtain liquefied natural gas (LNG). Therefore, adopting coke oven gas to prepare LNG technology, the components in coke oven gas can be effectively utilized, energy utilization rate is greatly improved, and environmental pollution is reduced.

[0003] In the coke coal gas liquefied natural gas, the process to be used is methanation cryogenic separation technology, the methane-rich gas after methanation reaction is cooled to-162 DEG C, at this time gaseous methane in methane-rich gas becomes LNG and is stored in LNG storage tank. This physical separation needs to use liquefied cold box, the heat exchange area of heat exchanger in cold box is large, the channel is multiple and the pipe diameter is small, the channel is thus easy to be blocked, the gas resistance increases after being blocked, the energy consumption increases, and the process equipment safety is influenced seriously when being serious;The liquid water (boiling point 0 DEG C under standard conditions) generated by methanation reaction can make the heat exchanger be blocked under the operating condition of cold box;Therefore, the water in methane-rich gas needs to be removed by drying and dehydrating before entering the cold box, the drying process adopts three drying towers to carry out adsorption, regeneration and cold blowing three stages circulation, and the regeneration needs to send the regeneration gas (1.3 MPa) into the drying tower after being heated by regeneration gas heater (the heat source of regeneration gas heater uses the 3.8 MPa, 435 DEG C medium pressure superheated steam of coking surplus to heat) to remove the water adsorbed in the drying tower and restore the molecular sieve activity of drying tower;If the medium pressure superheated steam leaks into the regeneration gas in this process, the regeneration of drying tower is not thorough, and the normal operation of cold box is influenced.

[0004] The coke oven gas liquefied natural gas process of prior art adopts low-temperature high-pressure adsorption and low-temperature high-pressure desorption technology in the drying and dehydrating section, and the regeneration gas heater is in the stoppage stage in the process of cutting three drying towers, so that the sealing surface of equipment is possibly leaked due to periodic fatigue operation, and the regeneration effect of drying tower is influenced. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a detection system about the leakage of regenerative gas heater, which is used to solve the technical problem of how to exclude the incomplete regeneration of drying tower caused by the leakage of regenerative gas heater.

[0006] The utility model is realized by the following technical solutions:

[0007] A detection system about the leakage of regenerative gas heater, including regenerative gas heater, heat exchanger, DCS control system, the regenerative gas heater process gas side import is connected with cold blow drying tower, the process gas heating after export connects regenerative drying tower, the regenerative gas heater heat source side import is connected with medium pressure superheated steam pipe network, the regenerative gas heater heat source side export connects gas-liquid separator.

[0008] The heat exchanger process gas import leads out a part of heated process gas through the pressure lead pipe, the heat exchanger process gas export is connected with torch, and the water dew point measuring instrument is connected between the heat exchanger and the torch, and the water dew point measuring instrument is connected to the DCS system.

[0009] When the application, the process gas in the cold blow drying tower enters the regenerative gas heater, the regenerative gas heater heats the process gas through the superheated steam, and the process gas after heating enters the regenerative drying tower, in order to check whether the process gas after heating is brought into the steam by the regenerative gas heater, a small part of the process gas is led out before the process gas after heating enters the regenerative drying tower, the led-out process gas enters the water dew point measuring instrument after cooling through the heat exchanger and is finally discharged into the torch, the water dew point measuring instrument transmits the analysis result of the process gas back to the DCS system, and when the steam leakage problem occurs, the system can be used to exclude the regenerative gas heater failure problem.

[0010] Further preferably, the heat exchanger import is provided with a sampling thermometer one, and the export is provided with a sampling thermometer two, since the water dew point measuring instrument is a precision instrument, in order to better protect the water dew point measuring instrument, the sampling thermometer two at the heat exchanger export is set, the cooling effect of the heat exchanger can be exactly known, and the sampling thermometer one at the heat exchanger import can know the heating effect of the regenerative gas heater.

[0011] Further preferably, the DCS system is provided with an alarm system, when the analysis data fed back by the water dew point measuring instrument to the DCS exceeds the threshold value, the alarm system is set, the operator can be reminded to handle as soon as possible, the operator does not need to stare at the screen all the time, and the automatic instrument control is further realized.

[0012] The utility model discloses a water dew point measuring instrument is arranged at the outlet of the regenerative gas heater, has two effects, first, can monitor whether the regenerative effect of cold blow tower is up to the standard, can know whether the regenerative effect of cold blow tower is up to the standard through the analysis data of water dew point measuring instrument, second, can carry out timely process adjustment to unqualified gas, can directly judge whether regenerative gas heater leaks, can guarantee the normal operation of cold box simultaneously, prolongs the service life of drying tower molecular sieve. BRIEF DESCRIPTION OF DRAWINGS

[0013] The accompanying drawings incorporated in and forming a part of the specification illustrate an embodiment consistent with the present utility model and serve to explain the principle of the present utility model together with the specification.

[0014] In order to more clearly illustrate the technical scheme in the embodiments of the present utility model or the prior art, the accompanying drawings needed to be used in the embodiment or prior art description will be briefly introduced, and obviously, other accompanying drawings can be obtained by those skilled in the art without creative labor on the premise of not paying the accompanying drawings.

[0015] Figure 1 The structure schematic diagram of the present utility model is shown.

[0016] In the drawing: 1-regenerative gas heater, 11-process gas side inlet, 12-heat source side inlet, 2-heat exchanger, 3-gas-liquid separator, 4-pressure lead pipe, 5-water dew point measuring instrument, 6-sampling thermometer one, 7-sampling thermometer two. DETAILED DESCRIPTION

[0017] In order to more clearly illustrate the above-mentioned purpose, features and advantages of the present utility model, the scheme of the present utility model will be further described below.It needs to be explained that the embodiment of the present utility model and the features in the embodiment can be combined with each other without conflict.

[0018] In the description, it needs to be explained that the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.It needs to be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, can be fixedly connected, can be detachably connected, or integrally connected, can be mechanically connected, or electrically connected, can be directly connected, or indirectly connected through an intermediate medium, can be the communication inside two elements.The specific meaning of the above-mentioned terms can be understood according to the specific circumstances by those skilled in the art.

[0019] Many specific details are set forth in the following description in order to provide a thorough understanding of the present application. However, the present application can be practiced according to other embodiments that can not be described in detail herein; obviously, the examples in the specification are only part of the embodiments of the present application, not all the embodiments.

[0020] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0021] A detection system for the leakage of a regenerative gas heater, comprising a regenerative gas heater 1, a heat exchanger 2, a DCS control system; the regenerative gas heater 1 is connected with a cold-blow drying tower at the inlet 11 of the process gas side, and is connected with a regenerative drying tower at the outlet of the process gas after heating; the heat source side inlet 12 of the regenerative gas heater 1 is connected with a medium-pressure superheated steam pipe network; the heat source side outlet of the regenerative gas heater 1 is connected with a gas-liquid separator 3.

[0022] The process gas inlet of the heat exchanger 2 is connected with a pressure lead pipe 4 to lead out a part of the heated process gas; the process gas outlet of the heat exchanger 2 is connected with a flare; the water dew point measuring instrument 5 is connected between the heat exchanger 2 and the flare; and the water dew point measuring instrument 5 is connected to the DCS system.

[0023] The sampling thermometer one 6 is arranged at the inlet of the heat exchanger 2, and the sampling thermometer two 7 is arranged at the outlet.

[0024] The DCS system is provided with an alarm system.

[0025] The pressure lead pipe 4 is generally a pipe with a diameter of φ5 or φ10; since the diameter of the pressure lead pipe 4 is small, only a small part of the process gas heated by the regenerative gas heater 1 can be led out, which will not affect the subsequent process after the regenerative gas heater 1; and the threshold value of the process gas temperature of the alarm system is generally-65℃.

[0026] The working principle is as follows:

[0027] The dew point instrument sampling pipe is arranged at the process gas outlet pipeline of the regenerative gas heater 1; the sampling thermometer one 6 is arranged on the sampling pipe; the sampling thermometer one 6 measures the temperature of the process gas after heating, which is used to evaluate the heating effect of the regenerative gas heater 1.

[0028] Subsequently, the process gas after cooling is sent into the water dew point measuring instrument 5 for analysis and detection of dew point, and then is sent into the flare for combustion; the water dew point measuring instrument 5 transmits the real-time analysis data to the central control room (DCS system) and adds the alarm system.

[0029] The process gas outlet of the regenerative gas heater 1 is connected with the regenerative drying tower; the pressure lead pipe 4 is arranged on the pipeline to connect the heat exchanger 2 to reduce the temperature to normal temperature, and the water dew point measuring instrument 5 is used for real-time analysis; the analysis result is transmitted to the central control DCS system, and the alarm reminds the operator.

[0030] The above merely describes specific implementation manners of the present application, and enables those skilled in the art to understand or implement the present application. Although the foregoing embodiments are described in detail, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some or all of the technical features can be replaced equivalently; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments, and should be covered in the protection scope of the claims.

Claims

1. A system for detecting leaks in a syngas heater, comprising: It includes regenerative gas heater (1), heat exchanger (2), DCS control system; the regenerative gas heater (1) process gas side import (11) is connected with cold blow drying tower, the process gas heating after export connects regenerative drying tower, the regenerative gas heater (1) heat source side import (12) is connected with medium pressure superheated steam pipe network, the regenerative gas heater (1) heat source side export connects gas-liquid separator (3); The heat exchanger (2) process gas import is guided out a part of heated process gas through pressure guide pipe (4), the heat exchanger (2) process gas export is connected with flare, the heat exchanger (2) and flare are connected with water dew point measuring instrument (5), the water dew point measuring instrument (5) is connected with DCS system.

2. A system for detecting leaks in a regenerative gas heater according to claim 1, wherein: The heat exchanger (2) import is provided with sampling thermometer one (6), and the export is provided with sampling thermometer two (7).

3. A system for detecting leaks in a regenerative gas heater as defined in claim 1, wherein: The DCS system is provided with alarm system.

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