Online detection system and method for water content of coal gas

Abstract

The invention belongs to the technical field of metallurgical gas detection, and particularly relates to a gas water content online detection system and method. The system comprises a water removal unit and a coal gas detection unit, wherein the water removal unit is used for removing water in coal gas; the coal gas detection unit is used for detecting the temperature, pressure and flow of the coal gas before and after water removal, and the water content of the coal gas is calculated according to the temperature, pressure and flow of the coal gas before and after water removal. The system does not need to meter the amount of water removed from the coal gas in the using process, the real-time water content in the coal gas can be calculated only by measuring the temperature, pressure and flow of the inlet and the outlet through the measuring device, and the measuring result is more accurate compared with direct measurement of the water content of the coal gas; meanwhile, the system can monitor the mechanical water content and the total water content in the coal gas in real time.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical gas detection, and in particular relates to an online detection system and method for gas water content. Background Art

[0002] In the iron and steel metallurgical industry, metallurgical gas is an important fuel supplied to various downstream processes for combustion. Common types of metallurgical gas in large integrated steel enterprises include blast furnace gas, coke oven gas and converter gas. Considering the different calorific values ​​of fuel required by heaters in different processes, enterprises use mixed gas for supply, and effectively control the calorific value by adjusting the proportion of the three types of gas in the mixed gas. As the end user, the steel rolling heating furnace often uses high coke-converter mixed gas as fuel for combustion. Different working conditions and processes of different gases will cause changes in the water content of the gas. The water content in the gas will affect the calorific value and will enter the steel rolling heating furnace with the gas, which will have a great impact on the surface quality of some products (such as affecting the surface decarburization layer, etc.). Therefore, online detection of the water content in metallurgical gas plays a very important role in regulating the water content in the gas.

[0003] The prior art discloses a "method and device for calculating the moisture content of coal gas produced by a blast furnace", the method comprising: obtaining the amount of physical water brought into the blast furnace charge, the amount of crystallization water brought into the raw material, the amount of water produced by hydrogen reduction, and the amount of water injected into the furnace top for cooling introduced into the blast furnace to be tested during a given ironmaking period; determining the total moisture content of the coal gas produced by the blast furnace based on the amount of physical water brought into the blast furnace charge, the amount of crystallization water brought into the raw material, the amount of water produced by hydrogen reduction, and the amount of water injected into the furnace top for cooling. The method is based on the ability to accurately calculate the percentage of moisture content in the coal gas, to correct the metering data of the instrument in real time, and to achieve accurate metering of dry coal gas; the prior art discloses a "device for detecting the moisture content of converter gas", comprising a sampling tube, a buffer bottle, A first transparent moisture absorption tube, a second transparent moisture absorption tube, a transparent colorimetric tube and a wet gas flowmeter, one side of the sampling tube is connected to a nitrogen backflush tube, the output end of the sampling tube is connected to the left side of the upper end of the buffer bottle, and the right side of the upper end of the buffer bottle is connected to the first conduit. The device weighs the buffer bottle, the first transparent moisture absorption tube, the second transparent moisture absorption tube, and the transparent colorimetric tube, and adds up the weight changes, which is the total mechanical water content of the converter gas, and then calculates the saturated water content corresponding to the gas temperature at that time. The sum of the two is the total water content of the converter gas, and then reads the gas flow through a wet gas flowmeter, and compares the total water content with the flow to obtain the water content of the converter gas per unit volume.

[0004] It can be seen from the detection methods of the prior art that the water content in coal gas is often detected in an offline manner. One or more desiccant are used to absorb the moisture in the coal gas. After a certain amount of coal gas is introduced, the weight increase of the desiccant is measured to calculate the water content in the coal gas. This method uses manual measurement, and the amount of water absorbed needs to be weighed each time. In addition to water, there are other substances in the coal gas that may be adsorbed by the desiccant, resulting in weight increase, etc., which has a large error. In addition, the coal gas has certain dangers and there is a risk of leakage. At the same time, due to the offline test, there is a certain lag, and it is impossible to reflect the water content of the pipe network coal gas in real time. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the manual measurement of moisture absorption weight in the prior art results in large errors and a certain hysteresis in the test results, thereby proposing an online detection system and method for the moisture content of coal gas. The system includes a coal gas detection unit and a dehydration unit, which are respectively arranged at the coal gas input port and the coal gas output port of the system of the present invention. The coal gas detection unit is used to detect the temperature, pressure and flow of the input and output coal gas, and the dehydration unit is used to remove the moisture in the input coal gas and output the dehydrated coal gas, and calculate the moisture content in the input coal gas according to the temperature, pressure and flow of the input and output coal gas. The system of the present invention does not need to measure the amount of water removed from the coal gas during use, and the real-time moisture content in the coal gas can be calculated by measuring the temperature, pressure and flow of the inlet and outlet by a measuring device. The measurement result is more accurate than directly measuring the moisture content of the coal gas, and the system can also realize real-time monitoring of the mechanical water and total water content in the coal gas.

[0006] In a first aspect, the present invention provides an online detection system for water content in coal gas, which includes a dehydration unit and a coal gas detection unit. The dehydration unit is used to remove water from the coal gas; the coal gas detection unit is used to detect the temperature, pressure and flow of the coal gas before and after dehydration, and calculate the mechanical water content in the coal gas according to the temperature, pressure and flow of the coal gas before and after dehydration. The calculation formula is as follows:

[0007]

[0008] Where W s is the mechanical water content in coal gas, g / Nm 3 ; T 1 is the temperature of the coal gas before water removal, ℃; P 1 is the pressure of the gas before water removal, Pa; Q 1 is the gas flow rate before water removal, m 3 / h; T 2 is the temperature of the gas after water removal, ℃; P 2is the pressure of the gas after water removal, Pa; Q 2 is the flow rate of coal gas after water removal, m 3 / h; W T1 T 1 Saturated water content in coal gas, g / m 3 ; W T2 T 2 Saturated water content in coal gas, g / m 3 ; Br is the local atmospheric pressure, Pa.

[0009] Preferably, the gas detection unit further includes a method for calculating the total water content in the gas according to the temperature, pressure and flow rate of the gas before and after water removal, and the calculation formula is as follows:

[0010]

[0011] Where W q is the total water content in coal gas, g / Nm 3 ; W s is the mechanical water content in coal gas, g / Nm 3 ; T 1 is the temperature of the coal gas before water removal, ℃; P 1 is the gas pressure before water removal, Pa; Q 1 is the gas flow rate before water removal, m 3 / h; T 2 is the temperature of the gas after water removal, ℃; P 2 is the pressure of the gas after water removal, Pa; Q 2 is the flow rate of coal gas after water removal, m 3 / h; W T1 T 1 Saturated water content in coal gas, g / m 3 ; W T2 T 2 Saturated water content in coal gas, g / m 3 ; Br is the local atmospheric pressure, Pa.

[0012] Preferably, the dehydration unit includes a condensation module and a drying module which are arranged in sequence along the flow direction of the coal gas, the condensation module is used to condense and dehydrate the input coal gas, and the drying module is used to dry and dehydrate the condensed and dehydrated coal gas; the coal gas detection unit includes a first coal gas detection module and a second coal gas detection module, the first coal gas detection module is located between the connecting pipe between the coal gas inlet and the condensation module, the first coal gas detection module is used to detect the temperature, pressure and flow of the coal gas before dehydration; the second coal gas detection module is located between the connecting pipe between the drying module and the coal gas outlet, the second coal gas detection module is used to detect the temperature, pressure and flow of the coal gas after dehydration.

[0013] More preferably, the condensing module includes an electric refrigeration tube and several stages of condensing devices connected in sequence; the drying module includes several independent drying devices; the first gas detection module includes a first pressure measuring device, a first temperature measuring device and a first flow measuring device arranged in sequence along the gas flow direction, and the second gas detection module includes a second pressure measuring device, a second temperature measuring device and a second flow measuring device arranged in sequence along the gas flow direction; the first flow measuring device is connected to a first-stage condensing device among several stages of condensing devices connected in sequence, and the gas pipeline connecting the first flow measuring device and the first-stage condensing device is wrapped with an electric refrigeration tube; the last-stage condensing device among several stages of condensing devices connected in sequence is respectively connected to several independent drying devices, and the gas pipeline connecting the last-stage condensing device and the drying device is wrapped with an electric refrigeration tube.

[0014] Further preferably, the drying device includes a drying tank and a moisture indicating tube which are connected in sequence along the flow direction of the gas; the last-stage condensing device is respectively connected to each drying tank in a number of independent drying devices, and the second pressure measuring device is respectively connected to each moisture indicating tube in a number of independent drying devices; a first valve is provided on the gas pipeline connecting the last-stage condensing device and each drying tank, and the first valve is used to control the condensed and dehydrated gas to enter the drying tank; a second valve is provided on the gas pipeline of the second pressure measuring device and each moisture indicating tube, and the second valve is used to control the dried and dehydrated gas to enter the second pressure measuring device for detection.

[0015] More preferably, the system further comprises a regeneration unit, the regeneration unit comprising a nitrogen bottle, a gas heater and a regeneration gas outlet; the gas heater heats the nitrogen from the nitrogen bottle, and transports the heated nitrogen to the drying tank, and utilizes the heated nitrogen to dehydrate and regenerate the desiccant in the drying tank, and the regeneration gas generated by the dehydration regeneration is discharged from the regeneration gas outlet through the moisture indicator tube; a third valve is provided on the nitrogen pipeline connecting the nitrogen bottle and the gas heater, a fourth valve is provided on the nitrogen pipeline connecting the gas heater and the drying tank, and a fifth valve is provided on the connecting pipeline between the moisture indicator tube and the regeneration gas outlet.

[0016] More preferably, the system also includes a detector, a controller, a sixth valve and a seventh valve; the detector is used to detect the color change of the color-changing agent in the moisture indicator tube in real time, and transmit the detected color change signal to the controller; the controller is used to receive signals output by the water removal unit, the gas detection unit, the regeneration unit and the detector, and control the water removal unit, the gas detection unit and the regeneration unit according to the output signals; the sixth valve is used to control the gas before water removal to enter the first gas detection module from the gas pipeline network, and the seventh valve is used to control the gas after water removal to be output to the gas pipeline network.

[0017] More preferably, the condensation device includes a water tank, a collecting funnel and a coil; the coil is used to increase the residence time of the coal gas inside the water tank, the collecting funnel is located at the bottom of the water tank, and the collecting funnel is used to collect moisture precipitated from the water tank; the condensation module also includes a drainage peristaltic pump and a condensate storage tank, and the drainage peristaltic pump is used to transport the moisture in the collecting funnel to the condensate storage tank for storage.

[0018] The second aspect of the present invention proposes an online detection method for the water content of coal gas implemented in the above-mentioned system, the method comprising: using a coal gas detection unit to measure the temperature, pressure and flow of the coal gas before water removal, passing the coal gas into the water removal unit for water removal, and then using the coal gas detection unit to measure the temperature, pressure and flow of the coal gas after water removal, and calculating the mechanical water content in the coal gas according to the temperature, pressure and flow of the coal gas before and after water removal, the calculation formula is as follows:

[0019]

[0020] Where W s is the mechanical water content in coal gas, g / Nm 3 ; T 1 is the temperature of the coal gas before water removal, ℃; P 1 is the gas pressure before water removal, Pa; Q 1 is the gas flow rate before water removal, m 3 / h; T 2 is the temperature of the gas after water removal, ℃; P 2 is the pressure of the gas after water removal, Pa; Q 2 is the flow rate of coal gas after water removal, m 3 / h; W T1 T 1 Saturated water content in coal gas, g / m 3 ; W T2 T 2 Saturated water content in coal gas, g / m 3 ; Br is the local atmospheric pressure, Pa.

[0021] Preferably, the gas detection unit further includes a method for calculating the total water content in the gas according to the temperature, pressure and flow rate of the gas before and after water removal, and the calculation formula is as follows:

[0022]

[0023] Where W q is the total water content in coal gas, g / Nm 3 ; W s is the mechanical water content in coal gas, g / Nm 3 ; T 1 is the temperature of the coal gas before water removal, ℃; P 1 is the gas pressure before water removal, Pa; Q 1 is the gas flow rate before water removal, m 3 / h; T 2 is the temperature of the gas after water removal, ℃; P 2 is the pressure of the gas after water removal, Pa; Q 2 is the flow rate of coal gas after water removal, m 3 / h; W T1 T 1 Saturated water content in coal gas, g / m 3 ; W T2 T 2 Saturated water content in coal gas, g / m 3 ; Br is the local atmospheric pressure, Pa.

[0024] In the system and method for online detection of water content in coal gas described in the present invention, at least the following are provided:

[0025] Beneficial effects:

[0026] (1) The system of the present invention uses a gas detection unit to detect the temperature, pressure and flow of the input and output gas, and uses a water removal unit to remove the water in the input gas, and calculates the water content in the input gas according to the temperature, pressure and flow of the input and output gas. The system of the present invention does not need to weigh the amount of water removed during use. It only needs to measure the temperature, pressure and flow of the inlet and outlet gas through the detection device to calculate the mechanical water and total water content in the gas in real time, which can effectively solve the problems of large test errors and inability to monitor the water content in the gas in real time in the existing detection methods;

[0027] (2) In the present invention, the system is also equipped with a fully automatic operation status monitoring and control system, which can automatically determine the operation status of the device, and the system is provided with a multi-stage water removal module to ensure that the mechanical water in the outlet gas is completely precipitated. The system can be adjusted according to the actual operation status of the device to ensure the long-term, stable, and online operation of the detection device; it can be used for real-time monitoring of the water content of various types of coal gas, and has a large application and promotion space. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of an online detection system for water content in coal gas according to an embodiment of the present invention;

[0029] Figure 2 This is a schematic structural diagram of a condensation module according to an embodiment of the present invention;

[0030] Figure 3 It is a schematic structural diagram of a drying module according to an embodiment of the present invention.

[0031] Reference numerals

[0032] 1. Condensation module; 11. Electric refrigeration tube; 12. Condensation device; 121. Water tank; 122. Collecting funnel; 123. Coil; 124. Drainage peristaltic pump; 125. Condensate storage tank; 2. Drying module; 21. Drying device; 211. Drying tank; 212. Moisture indicator tube; 3. First gas detection module; 31. First pressure measuring device; 32. First temperature measuring device; 33. First flow measuring device; 4. Second gas detection module; 41. Second pressure measuring device; 42. Second temperature measuring device; 43. Second flow measuring device; 51. First valve; 52. Second valve; 53. Third valve; 54. Fourth valve; 55. Fifth valve; 56. Sixth valve; 57. Seventh valve; 58. Eighth valve; 59. Drainage valve; 61. Nitrogen bottle; 62. Gas heater; 63. Regeneration gas outlet; 7. Detector; 8. Controller; 9. Booster fan. DETAILED DESCRIPTION

[0033] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0034] The first aspect of the present invention provides an online detection system for water content in coal gas, such as Figure 1 As shown, the system includes a dehydration unit and a gas detection unit. The dehydration unit is used to remove moisture from the coal gas; the coal gas detection unit is used to detect the temperature, pressure and flow of the coal gas before and after dehydration, and calculate the water content of the coal gas based on the temperature, pressure and flow of the coal gas before and after dehydration.

[0035] In a specific embodiment of the system of the present invention, a specific method for calculating the water content of coal gas based on the temperature, pressure and flow rate of coal gas before and after water removal is as follows: The calculation formula of the mechanical water content in coal gas is shown in formula (1):

[0036]

[0037] Where W s is the mechanical water content in coal gas, g / Nm 3 ; T 1 is the temperature of the coal gas before water removal, ℃; P 1 is the pressure of the gas before water removal, Pa; Q 1 is the gas flow rate before water removal, m 3 / h; T 2 is the temperature of the gas after water removal, ℃; P 2 is the pressure of the gas after water removal, Pa; Q 2 is the flow rate of coal gas after water removal, m 3 / h; W T1 T 1 Saturated water content in coal gas, g / m 3 ; W T2 T 2 Saturated water content in coal gas, g / m 3 ; Br is the local atmospheric pressure, Pa.

[0038] The calculation formula for the total water content in coal gas is shown in formula (2):

[0039]

[0040] Where W q is the total water content in coal gas, g / Nm 3 ; W s is the mechanical water content in coal gas, g / Nm 3 ; T 1 is the temperature of the coal gas before water removal, ℃; P 1 is the pressure of the gas before water removal, Pa; Q 1 is the gas flow rate before water removal, m 3 / h; T 2 is the temperature of the gas after water removal, ℃; P 2 is the pressure of the gas after water removal, Pa; Q 2 is the flow rate of coal gas after water removal, m 3 / h; W T1 T 1 Saturated water content in coal gas, g / m 3 ; W T2 T 2 Saturated water content in coal gas, g / m3 ; Br is the local atmospheric pressure, Pa.

[0041] In a preferred embodiment of the system of the present invention, the system further comprises a controller 8, wherein the controller 8 is used to receive signals output by the water removal unit and the gas detection unit, and control the water removal unit and the gas detection unit according to the output signals.

[0042] In a specific embodiment of the system of the present invention, the dehydration unit includes a condensation module 1 and a drying module 2 which are arranged in sequence along the flow direction of the coal gas, the condensation module 1 is used to condense and dehydrate the input coal gas, and the drying module 2 is used to dry and dehydrate the condensed and dehydrated coal gas; the coal gas detection unit includes a first coal gas detection module 3 and a second coal gas detection module 4, the first coal gas detection module 3 is located between the connecting pipe between the coal gas inlet and the condensation module 1, and the first coal gas detection module 3 is used to detect the temperature, pressure and flow of the coal gas before dehydration; the second coal gas detection module 4 is located between the connecting pipe between the drying module 2 and the coal gas outlet, and the second coal gas detection module 4 is used to detect the temperature, pressure and flow of the coal gas after dehydration.

[0043] In a specific embodiment of the system of the present invention, the system also includes a booster fan 9, which is located between the second gas detection module 4 and the connecting pipe of the gas outlet. The booster fan 9 is of explosion-proof design and has a boosting capacity of (0~5kPa). The booster fan 9 is mainly used to transport the dried gas back to the gas pipeline network.

[0044] In a specific embodiment of the system of the present invention, the first gas detection module 3 includes a first pressure measuring device 31, a first temperature measuring device 32 and a first flow measuring device 33 which are sequentially arranged along the gas flow direction.

[0045] In the present invention, the first pressure measuring device 31 is a digital pressure sensor with a measuring range of (-0.1~100kPa), a minimum response signal of 1Pa, a response time of ≤10ms, and a pressure signal directly transmitted to the controller 8, which can monitor and display the change of gas pressure in real time; the first temperature measuring device 32 is a K-type armored thermocouple with a measuring range of (0~500℃), a minimum response signal of 0.1℃, and a thermocouple signal directly transmitted to the controller 8, which can monitor and display the change of gas temperature in real time; the first flow measuring device 33 is an electromagnetic flowmeter with operating flow recording and signal output functions. The signal is directly transmitted to the controller 8, which can monitor and display the change of flow during the test in real time.

[0046] In the present invention, the condensation module 1 has a temperature adjustable function, which can be directly linked with the controller 8 to achieve the regulation of the condensation temperature, and the temperature range is: -10 to 20°C.

[0047] In a specific embodiment of the system of the present invention, Figure 2 As shown, the condensing module 1 includes an electric refrigeration tube 11 and a plurality of sequentially connected condensing devices 12, the electric refrigeration tube 11 is wrapped around the gas pipeline entering and outputting the plurality of sequentially connected condensing devices 12, the electric refrigeration tube 11 is used to keep the gas before and after condensation cold (temperature control range: -5 ~ 20 ° C); the condensing device 12 includes a water tank 121, a collecting funnel 122 and a coil 123, the first flow measuring device 33 is connected to the water tank 121 through a gas pipeline, and the gas One end of the pipeline is connected to the coil 123 located inside the water tank 121, and the coil 123 is used to increase the residence time of the coal gas inside the water tank 121 to ensure that the gas is cooled to a specified temperature; the liquid water precipitated from the coal gas after condensation to remove mechanical water and saturated water is collected through a collecting funnel 122; the condensation module 1 also includes a drainage peristaltic pump 124 and a condensed water storage tank 125, and the drainage peristaltic pump 124 is used to transport the liquid water in the collecting funnel 122 to the condensed water storage tank 125 for storage.

[0048] In the present invention, the drainage peristaltic pump 124 has a drainage capacity of 0 to 380 mL / min and is equipped with a communication transmission line, and the peristaltic pump is controlled by the controller 8; the condensate storage tank 125 is equipped with a drainage valve 59, and a water level sensor is provided inside the condensate storage tank 125, and drainage is automatically performed when the drainage liquid level is reached.

[0049] In a preferred embodiment of the system of the present invention, the condensation module 1 includes an electric refrigeration tube 11, two-stage condensation devices 12 connected in sequence, a drainage peristaltic pump 124 and a condensed water storage tank 125. The condensation module 1 can be used to complete two-stage deep cooling and water removal, and the equipment cost, that is, the operating cost, is relatively low.

[0050] In a specific embodiment of the system of the present invention, Figure 3 As shown, the drying module 2 includes a plurality of mutually independent drying devices 21, and the drying device 21 includes a drying tank 211 and a moisture indicator tube 212 which are sequentially connected along the gas flow direction. The water tank 121 in the last-stage condensing device 12 in the condensing module 1 is respectively connected to the drying tanks 211 in the plurality of mutually independent drying devices 21. The drying tank is filled with a water-absorbing molecular sieve. The gas after deep cooling and dehydration in the condensing module 1 is further absorbed by the moisture in the gas through the drying tank 211. The moisture indicator tube 212 is filled with a color-changing agent (color-changing silica gel particles) which changes color when in contact with water.

[0051] In a preferred embodiment of the system of the present invention, the system also includes a detector 7, which is located next to the moisture indicator tube 212. The detector 7 is used to detect the color change of the color-changing agent in the moisture indicator tube 212 in real time, and transmit the detected color change signal to the controller 8, and then perform gas path switching.

[0052] In a specific embodiment of the system of the present invention, a first valve 51 is provided on the gas pipeline connecting the last-stage condensing device 12 and each drying tank 211 in the system, and the first valve 51 is used to control the condensed and dehydrated gas to enter the drying tank 211; a second valve 52 is provided on the gas pipeline connecting the second pressure measuring device 41 and each moisture indicating tube 212, and the second valve 52 is used to control the dried and dehydrated gas to enter the second pressure measuring device 41 for detection.

[0053] In a preferred embodiment of the system of the present invention, the drying module 2 includes two independent drying devices 21, and the drying module 2 can be used to further dry and dehydrate the coal gas after deep cooling and dehydration, and the equipment cost, ie, the operating cost, is relatively low.

[0054] In a preferred embodiment of the system of the present invention, the system further includes a regeneration unit, which includes a nitrogen bottle 61, a gas heater 62 and a regeneration gas outlet 63; the gas heater 62 heats the nitrogen from the nitrogen bottle 61, and transports the heated nitrogen to the drying tank 211, and uses the heated nitrogen to dehydrate and regenerate the desiccant in the drying tank 211, and the regeneration gas generated by the dehydration regeneration passes through the moisture indicator tube 212 and is discharged from the regeneration gas outlet 63; a third valve 53 is provided on the nitrogen pipeline connecting the nitrogen bottle 61 and the gas heater 62, a fourth valve 54 is provided on the nitrogen pipeline connecting the gas heater 62 and the drying tank 211, and a fifth valve 55 is provided on the connecting pipeline between the moisture indicator tube 212 and the regeneration gas outlet 63.

[0055] In this article, the nitrogen bottle 61 is filled with 99.99% dry nitrogen, and the nitrogen bottle 61 is equipped with a pressure reducing valve, and the purge pressure is 10-20 kPa; the nitrogen is heated to a specified temperature by the gas heater 62 to remove water and regenerate the desiccant in the drying tank 211; the nitrogen pipeline is a stainless steel pipeline.

[0056] In this article, the gas heater 62 is an electric heating explosion-proof design, which can heat the purge gas in the temperature range of (20-200°C). The gas heater 62 is equipped with signal input and output, which can be connected to the controller 8 and controlled by the controller 8.

[0057] In a specific embodiment of the system of the present invention, the second gas detection module 4 includes a second pressure measuring device 41, a second temperature measuring device 42 and a second flow measuring device 43 which are sequentially arranged along the gas flow direction.

[0058] In the present invention, the second pressure measuring device 41 is a digital pressure sensor with a measuring range of (-0.1~100kPa), a minimum response signal of 1Pa, a response time of ≤10ms, and a pressure signal directly transmitted to the controller 8, which can monitor and display the change of gas pressure in real time; the second temperature measuring device 42 is a K-type armored thermocouple with a measuring range of (0~500℃), a minimum response signal of 0.1℃, and a thermocouple signal directly transmitted to the controller 8, which can monitor and display the change of gas temperature in real time; the second flow measuring device 43 is an electromagnetic flowmeter with operating flow recording and signal output functions. The signal is directly transmitted to the controller 8, which can monitor and display the change of flow during the test in real time.

[0059] In a specific embodiment of the system of the present invention, the system further includes a sixth valve 56, a seventh valve 57 and an eighth valve 58; the sixth valve 56 is used to control the gas before water removal from the gas network to enter the first gas detection module 3, the seventh valve 57 is used to control the gas after water removal to be output to the gas network, and the eighth valve 58 is reserved for access to compressed air or other medium gases, and can also be used as a relief valve.

[0060] In this article, the first valve 51 to the eighth valve 58 and the drain valve 59 are all electrically controlled valves and are provided with a signal input and output system, which can be connected to the controller 8 and controlled by the controller 8, and the valves are made of stainless steel. Specifically, the valve switch should have a clear signal transmitted to the controller 8, and the response time is ≤0.5S.

[0061] In a specific embodiment of the system of the present invention, the controller 8 has signal control and input and output functions, can realize the display, calculation and transmission of the detection parameters of the device, and can control the device according to the internally designed process flow to realize the switching of various states. Specifically, when the condensing module 1 in the system of the present invention includes an electric refrigeration pipe 11, a two-stage condensing device 12 connected in sequence, a drainage peristaltic pump 124 and a condensed water storage tank 125, and the drying module 2 includes two independent drying devices 21, the conditions of each state are as follows: State 1: Running state, open the sixth valve 56 and the first valve 5 connected to the first drying device 21 1 and the second valve 52, and the seventh valve 57 is opened at the same time, the inlet and outlet gas parameters are recorded in real time, the electric refrigeration tube 11 and the condensing device 12 work according to the set temperature (usually 0°C), the drainage peristaltic pump 124 and the booster fan 9 are started, and the system calculates the water content in the gas according to the gas parameters, and the detector 7 starts to monitor the changes in the moisture indicator tube 212; State 2: When the detector 7 detects the color change in the moisture indicator tube 212, the system enters state 2, at this time, the first valve 51 and the second valve 52 connected to the first drying device 21 are closed, and the first valve 51 and the second valve 52 connected to the second drying device 21 are opened, and the other valves remain unchanged and the equipment unchanged; State three: purge regeneration state 1, under the condition of state two, open the third valve 53, and at the same time open the fourth valve 54 and the fifth valve 55 connecting the gas heater 62 and the first drying device 21, purge the drying tank 211 in the first drying device 21 for 30 to 60 seconds, then the gas heater 62 starts to work, heats the purge gas (120°C), and regenerates the water-absorbing molecular sieve in the drying tank 211 until the color-changing agent in the moisture indicator tube 212 returns to its original state, then stops regeneration, closes the third valve 53 and the fourth valve 54 and the fifth valve connecting the gas heater 62 and the first drying device 21 55; State four: Purge regeneration state 2, in the pre-state, open the third valve 53, and at the same time open the fourth valve 54 and the fifth valve 55 connecting the gas heater 62 and the second drying device 21, and purge the drying tank 211 in the second drying device 21 for 30 to 60 seconds, then the gas heater 62 starts to work, heats the purge gas (120°C), and regenerates the water-absorbing molecular sieve in the drying tank 211 until the color-changing agent in the moisture indicator tube 212 returns to its original state, then stops regeneration, and closes the third valve 53 and the fourth valve 54 and the fifth valve 55 connecting the gas heater 62 and the second drying device 21. State five: Drainage state, when the water level in the condensed water storage tank 125 reaches the drainage condition, open the drainage valve 59, and when the water is drained, close the drainage valve 59.

[0062] In this article, when the system is connected to the gas pipe, all internal desiccants, indicators, etc. are updated, when everything is ready, turn on the system switch and switch to state 1. During operation, when the detector 7 detects the color change in the moisture indicator tube 212, the system enters state 2, and at the same time, the system enters state 3, and the drying tank 211 in the first failed drying device 21 is regenerated. When the detector 7 detects the color change in the moisture indicator tube 212, the system valve switches back to state 1, and the system enters state 4; the above cycle is repeated during the operation of the system. At the same time, during operation, when the water level in the condensed water storage tank 125 reaches the drainage condition, the system automatically superimposes and runs state 5 once. The control system calculates the mechanical water and saturated water content in the gas based on the inlet and outlet gas data obtained by real-time sampling.

[0063] The second aspect of the present invention proposes an online detection method for the water content of coal gas in the above-mentioned system, the method comprising: using a coal gas detection unit to measure the temperature, pressure and flow of the coal gas before water removal, passing the coal gas into the water removal unit for water removal, and then using the coal gas detection unit to measure the temperature, pressure and flow of the coal gas after water removal, and calculating the water content of the coal gas based on the temperature, pressure and flow of the coal gas before and after water removal.

[0064] In a specific implementation of the method of the present invention, the specific method for calculating the water content of the coal gas according to the temperature, pressure and flow rate of the coal gas before and after dehydration is as follows: The calculation formula of the mechanical water content in the coal gas is shown in formula (1):

[0065]

[0066] Where W s is the mechanical water content in coal gas, g / Nm 3 ; T 1 is the temperature of the coal gas before water removal, ℃; P 1 is the pressure of the gas before water removal, Pa; Q 1 is the gas flow rate before water removal, m 3 / h; T 2 is the temperature of the gas after water removal, ℃; P 2 is the pressure of the gas after water removal, Pa; Q 2 is the flow rate of coal gas after water removal, m 3 / h; W T1 T 1 Saturated water content in the gas, g / m 3 ; W T2 T 2 Saturated water content in the gas, g / m 3 ; Br is the local atmospheric pressure, Pa;

[0067] The calculation formula for the total water content in coal gas is shown in formula (2):

[0068]

[0069] Where W q is the total water content in coal gas, g / Nm 3 ; W s is the mechanical water content in coal gas, g / Nm 3 ; T 1 is the temperature of the coal gas before water removal, ℃; P 1 is the gas pressure before water removal, Pa; Q 1 is the gas flow rate before water removal, m 3 / h; T 2 is the temperature of the gas after water removal, ℃; P 2 is the pressure of the gas after water removal, Pa; Q 2 is the flow rate of coal gas after water removal, m 3 / h; W T1 T 1 Saturated water content in the gas, g / m 3 ; W T2 T 2 Saturated water content in the gas, g / m 3 ; Br is the local atmospheric pressure, Pa.

[0070] The experimental methods or test methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials are obtained from conventional commercial channels or prepared by conventional methods unless otherwise specified.

[0071] Example 1

[0072] A gas water content online detection system, such as Figures 1 to 3As shown, the system includes a dehydration unit, a gas detection unit, a regeneration unit, a detector 7 and a controller 8. The controller 8 receives signals output by the dehydration unit, the gas detection unit, the regeneration unit and the detector 7, and controls the dehydration unit, the gas detection unit and the regeneration unit according to the output signals; the dehydration unit includes a condensation module 1 and a drying module 2 arranged in sequence along the gas flow direction; the gas detection unit includes a first gas detection module 3 and a second gas detection module 4; the first gas detection module 3 is located between the gas inlet and the connecting pipe of the condensation module 1; the connection between the first gas detection module 3 and the gas inlet A sixth valve 56 is arranged on the connecting pipe; the second gas detection module 4 is located between the connecting pipe of the drying module 2 and the gas outlet; a booster fan 9 and a seventh valve 57 are arranged in sequence along the gas flow direction on the connecting pipe between the second gas detection module 4 and the gas outlet; the first gas detection module 3 includes a first pressure measuring device 31, a first temperature measuring device 32 and a first flow measuring device 33 arranged in sequence along the gas flow direction; the second gas detection module 4 includes a second pressure measuring device 41, a second temperature measuring device 42 and a second flow measuring device 43 arranged in sequence along the gas flow direction; the condensing module 1 includes an electric A refrigeration pipe 11, a condensing device 12 connected in two stages in sequence, a drainage peristaltic pump 124 and a condensed water storage tank 125, the electric refrigeration pipe 11 is wrapped outside the gas pipeline of the condensing device 12 for inputting and outputting gas, the condensing device 12 includes a water tank 121, a collecting funnel 122 and a coil 123, the coil 123 is placed inside the water tank 121, the collecting funnel 122 is located at the bottom of the water tank 121, the collecting funnel 122 is connected to the condensed water storage tank 125, and a drainage peristaltic pump 124 is provided on the connecting pipe between the collecting funnel 122 and the condensed water storage tank 125, and the drainage peristaltic pump 124 has a drainage valve 59 The drying module 2 includes two independent drying devices 21, and the drying device 21 includes a drying tank 211 (the drying tank is equipped with 4A molecular sieve) and a moisture indicator tube 212 which are sequentially connected along the gas flow direction. The last-stage condensing device 12 is respectively connected to the two drying tanks 211, and the connecting pipeline between the last-stage condensing device 12 and the drying tank 211 is provided with a first valve 51. The two moisture indicator tubes 212 are both connected to the second pressure measuring device 41, and the connecting pipeline between the moisture indicator tube 212 and the second pressure measuring device 41 is provided with a second valve 52. The detector 7 is located next to the moisture indicator tube 212;The regeneration unit includes a nitrogen bottle 61, a gas heater 62 and a regeneration gas outlet 63. The nitrogen bottle 61 is connected to the gas heater 62. A third valve 53 is provided on the nitrogen pipeline connecting the nitrogen bottle 61 and the gas heater 62. At the same time, another nitrogen pipeline with an eighth valve 58 is opened on the nitrogen pipeline connecting the nitrogen bottle 61 and the gas heater 62. The gas heater 62 is respectively connected to two drying tanks 211, and a fourth valve 54 is provided on the connecting pipeline between the gas heater 62 and the drying tank 211. Both of the two moisture indicator tubes 212 are connected to the regeneration gas outlet 63, and a fifth valve 55 is provided on the connecting pipeline between the regeneration gas outlet 63 and the moisture indicator tube 212. ;

[0073] According to the method for online detection of water content in coal gas of the system described in Example 1, the method comprises: opening the sixth valve 56 and the first valve 51 and the second valve 52 connected to the first drying device 21, and opening the seventh valve 57 at the same time, the electric refrigeration tube 11 and the condensing device 12 operate at a set temperature (generally 0° C.), starting the drainage peristaltic pump 124 and the booster fan 9, and the detector 7 starts to monitor the changes of the water content indicator tube 212, and records the inlet and outlet coal gas parameters in real time, P 1 is 0Pa, T 1 At 30℃, Q 1 1m 3 / h,P 2 is 0Pa, T 2 At 0°C, Q 2 0.8685m 3 / h, the system calculates the mechanical water content in the gas according to the gas parameters and it is 0g / Nm 3 , the total water content is 33.74g / Nm 3 .

[0074] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A gas water content online detection system, characterized in that: The system comprises a water removal unit and a coal gas detection unit, wherein the water removal unit is used to remove moisture from the coal gas; The gas detection unit is used to detect the temperature, pressure and flow rate of the gas before and after water removal, and calculate the mechanical water content in the gas according to the temperature, pressure and flow rate of the gas before and after water removal. The calculation formula is as follows: Where W s is the mechanical water content in coal gas, g / Nm 3 ; T1 is the temperature of the coal gas before dehydration, ℃; P1 is the pressure of the coal gas before dehydration, Pa; Q1 is the flow rate of the coal gas before dehydration, m 3 / h; T2 is the temperature of the gas after dehydration, ℃; P2 is the pressure of the gas after dehydration, Pa; Q2 is the flow rate of the gas after dehydration, m 3 / h; W T1 is the saturated water content in the gas at T1, g / m 3 ; W T2 is the saturated water content in the gas at T2, g / m 3 ; Br is the local atmospheric pressure, Pa.

2. The on-line detection system for water content in coal gas according to claim 1, characterized in that: The gas detection unit also includes calculating the total water content in the gas according to the temperature, pressure and flow rate of the gas before and after water removal, and the calculation formula is as follows: Where W q is the total water content in coal gas, g / Nm 3 ; W s is the mechanical water content in coal gas, g / Nm 3 ; T1 is the temperature of the coal gas before dehydration, ℃; P1 is the pressure of the coal gas before dehydration, Pa; Q1 is the flow rate of the coal gas before dehydration, m 3 / h; T2 is the temperature of the gas after dehydration, ℃; P2 is the pressure of the gas after dehydration, Pa; Q2 is the flow rate of the gas after dehydration, m 3 / h; W T1 is the saturated water content in the gas at T1, g / m 3 ; W T2 is the saturated water content in the gas at T2, g / m 3 ; Br is the local atmospheric pressure, Pa.

3. The on-line detection system for water content in coal gas according to claim 1, characterized in that: The dehydration unit comprises a condensation module (1) and a drying module (2) which are arranged in sequence along the flow direction of the coal gas, the condensation module (1) being used to condense and dehydrate the input coal gas, and the drying module (2) being used to dry and dehydrate the condensed and dehydrated coal gas; The gas detection unit comprises a first gas detection module (3) and a second gas detection module (4), wherein the first gas detection module (3) is located between the gas inlet and the connecting pipe of the condensation module (1), and the first gas detection module (3) is used to detect the temperature, pressure and flow of the gas before water removal; The second gas detection module (4) is located between the drying module (2) and the connecting pipe of the gas outlet, and the second gas detection module (4) is used to detect the temperature, pressure and flow of the gas after water removal.

4. The on-line detection system for water content in coal gas according to claim 3 is characterized in that: The condensing module (1) comprises an electric refrigeration tube (11) and a plurality of stages of condensing devices (12) connected in sequence; the drying module (2) comprises a plurality of mutually independent drying devices (21); The first gas detection module (3) comprises a first pressure measuring device (31), a first temperature measuring device (32) and a first flow measuring device (33) which are sequentially arranged along the gas flow direction, and the second gas detection module (4) comprises a second pressure measuring device (41), a second temperature measuring device (42) and a second flow measuring device (43) which are sequentially arranged along the gas flow direction; The first flow measurement device (33) is connected to a first-stage condensation device (12) among a plurality of stages of condensation devices (12) connected in sequence, and the gas pipeline connecting the first flow measurement device (33) and the first-stage condensation device (12) is wrapped with an electric refrigeration tube (11); The last stage condensing device (12) of the plurality of stages of condensing devices (12) connected in sequence is respectively connected to a plurality of mutually independent drying devices (21), and the gas pipeline connecting the last stage condensing device (12) and the drying device (21) is wrapped with an electric refrigeration tube (11).

5. The on-line detection system for water content in coal gas according to claim 4 is characterized in that: The drying device (21) comprises a drying tank (211) and a moisture indicator tube (212) which are sequentially connected along the flow direction of the coal gas; The last-stage condensing device (12) is respectively connected to each drying tank (211) in a plurality of mutually independent drying devices (21), and the second pressure measuring device (41) is respectively connected to each moisture indicating tube (212) in a plurality of mutually independent drying devices (21); A first valve (51) is provided on the gas pipeline connecting the last-stage condensing device (12) and each drying tank (211), and the first valve (51) is used to control the condensed and dehydrated gas to enter the drying tank (211); The second pressure measuring device (41) and the gas pipeline of each moisture indicating tube (212) are both provided with a second valve (52), and the second valve (52) is used to control the dried and dehydrated gas to enter the second pressure measuring device (41) for detection.

6. The on-line detection system for water content in coal gas according to claim 5, characterized in that: The system also includes a regeneration unit, which includes a nitrogen bottle (61), a gas heater (62) and a regeneration gas outlet (63); The gas heater (62) heats the nitrogen from the nitrogen bottle (61), and transports the heated nitrogen to the drying tank (211), and uses the heated nitrogen to dehydrate and regenerate the desiccant in the drying tank (211), and the regenerated gas generated by the dehydration regeneration passes through the moisture indicator tube (212) and is discharged from the regenerated gas outlet (63); A third valve (53) is provided on the nitrogen pipeline connecting the nitrogen bottle (61) and the gas heater (62), a fourth valve (54) is provided on the nitrogen pipeline connecting the gas heater (62) and the drying tank (211), and a fifth valve (55) is provided on the connecting pipeline between the moisture indicator tube (212) and the regeneration gas outlet (63).

7. The on-line detection system for water content in coal gas according to claim 6, characterized in that: The system also includes a detector (7), a controller (8), a sixth valve (56) and a seventh valve (57); The detector (7) is used to detect the color change of the color changing agent in the moisture indicating tube (212) in real time, and transmit the detected color change signal to the controller (8); The controller (8) is used to receive signals output by the water removal unit, the gas detection unit, the regeneration unit and the detector (7), and to control the water removal unit, the gas detection unit and the regeneration unit according to the output signals; The sixth valve (56) is used to control the coal gas before water removal from the gas pipe network to enter the first coal gas detection module (3), and the seventh valve (57) is used to control the coal gas after water removal to be output to the gas pipe network.

8. The on-line detection system for water content in coal gas according to claim 4, characterized in that: The condensing device (12) comprises a water tank (121), a collecting funnel (122) and a coil (123); The coil (123) is used to increase the residence time of the coal gas inside the water tank (121); the collecting funnel (122) is located at the bottom of the water tank (121); the collecting funnel (122) is used to collect water precipitated from the water tank (121); The condensation module (1) further comprises a drainage peristaltic pump (124) and a condensed water storage tank (125); the drainage peristaltic pump (124) is used to transport the water in the collection funnel (122) to the condensed water storage tank (125) for storage.

9. An on-line method for detecting water content in coal gas according to the system of any one of claims 1 to 8, characterized in that: The method comprises: using a gas detection unit to measure the temperature, pressure and flow of the gas before water removal, passing the gas into the water removal unit for water removal, and then using the gas detection unit to measure the temperature, pressure and flow of the gas after water removal, and calculating the mechanical water content in the gas according to the temperature, pressure and flow of the gas before and after water removal, and the calculation formula is as follows: Where W s is the mechanical water content in coal gas, g / Nm 3 ; T1 is the temperature of the gas before dehydration, ℃; P1 is the pressure of the gas before dehydration, Pa; Q1 is the flow rate of the gas before dehydration, m 3 / h; T2 is the temperature of the gas after dehydration, ℃; P2 is the pressure of the gas after dehydration, Pa; Q2 is the flow rate of the gas after dehydration, m 3 / h; W T1 is the saturated water content in the gas at T1, g / m 3 ; W T2 is the saturated water content in the gas at T2, g / m 3 ; Br is the local atmospheric pressure, Pa.

10. The method according to claim 9, characterized in that: The method also includes calculating the total water content in the coal gas according to the temperature, pressure and flow rate of the coal gas before and after dehydration, and the calculation formula is as follows: Where W q is the total water content in coal gas, g / Nm 3 ; W s is the mechanical water content in coal gas, g / Nm 3 ; T1 is the temperature of the coal gas before dehydration, ℃; P1 is the pressure of the coal gas before dehydration, Pa; Q1 is the flow rate of the coal gas before dehydration, m 3 / h; T2 is the temperature of the gas after dehydration, ℃; P2 is the pressure of the gas after dehydration, Pa; Q2 is the flow rate of the gas after dehydration, m 3 / h; W T1 is the saturated water content in the gas at T1, g / m 3 ; W T2 is the saturated water content in the gas at T2, g / m 3 ; Br is the local atmospheric pressure, Pa.

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