High-precision mercury standard gas generation system and method

Abstract

The invention discloses a high-precision mercury standard gas generation system and method. The system comprises a carrier gas supply module, a mercury source evaporation module, a heat dilution mixing module, a sound speed small hole constant flow module and an intelligent control system, an outlet of the carrier gas supply module is communicated with an inlet of the mercury source evaporation module and an inlet of the heat dilution mixing module, an outlet of the mercury source evaporation module is communicated with an inlet of the sound speed small hole constant flow module, and an outlet of the sound speed small hole constant flow module is communicated with an inlet of the heat dilution mixing module; and the intelligent control system is connected with the carrier gas supply module and the heat dilution mixing module. The system and the method can generate mercury standard gas with relatively high precision.

Description

Technical Field

[0001] The invention belongs to the technical field of coal-burning air pollutant control and relates to a high-precision mercury standard gas generation system and method. Background Art

[0002] Faced with the severe mercury pollution situation and the serious consequences of mercury emissions, the international community has successively introduced strict mercury emission standards and imposed strict restrictions on mercury emissions. Therefore, it is of great significance to conduct morphological detection of mercury emissions from industrial sources such as coal-fired power plants. Since mercury standard gas cannot be stored in gas cylinders, unlike conventional CEMS systems, the mercury continuous online monitoring system (Hg-CEMS) needs to be regularly calibrated through the mercury standard gas generation system to calibrate the system accuracy.

[0003] Patent with authorization announcement number CN102692481B: Mercury standard gas generating device, the device includes five units, namely: an insulation unit, provided with an inner liner and an insulation layer, a vacuum insulation layer between the inner liner and the insulation layer, the unit is provided with a compensation gas inlet, a temperature measuring port and a sampling port; a mercury standard source penetration unit, arranged at the bottom of the inner liner of the insulation unit, including a quartz container and a slow-release membrane encapsulated at its mouth; the slow-release membrane adopts a quartz slow-release membrane or a ceramic slow-release membrane, and the pore size range is 10-200μm. The compensation gas purification unit is arranged outside the insulation unit, including an adsorption column and control valves at both ends of the adsorption column, the adsorption column is connected to the quartz container; a constant temperature control unit, including a temperature controller, a constant temperature tank and a circulating heating sleeve, the circulating heating sleeve is placed in the inner liner; a sampling unit, provided with a sampler, collects the mercury standard gas in the insulation unit through the sampling port, the mercury standard gas generating device adopts a compensation gas slow-in and mercury-containing gas slow-release structure design, it has the function of enabling the system to recover quickly. The purified clean compensation gas slowly enters the mercury standard source permeation unit through the capillary, is evenly mixed with the mercury vapor evaporated at a constant temperature, and is carried and slowly released through the slow-release membrane. The mercury-containing gas that has passed through the slow-release membrane has basically reached saturation. In this way, the container can be compensated and quickly restore balance after consuming the mercury-containing standard gas, and the concentration of the mercury standard gas can be restored to a constant level in a short time, which can be used for continuous calibration.

[0004] The above mercury standard gas generation technology is the mainstream standard gas generation technology for laboratories / mercury online monitoring systems. Its principle is the saturated evaporation method of mercury. Mercury vapor is carried into the standard gas system through a carrier gas. Since the relationship between mercury vapor concentration and temperature can be accurately described by the Dumarey equation, the mercury vapor concentration can be adjusted by adjusting the temperature. However, although the Dumarey equation can accurately calculate the saturated vapor concentration of mercury in a closed container, when mercury vapor is carried by a carrier gas, the pressure and flow state of the subsequent pipeline will cause the carried mercury vapor concentration to fluctuate, making it difficult for the mercury standard gas generated by the saturated evaporation method of mercury to meet the requirements of high-precision calibration in terms of accuracy. In addition, the saturated mercury vapor generated by saturated evaporation will partially condense when it contacts the subsequent pipeline, affecting the mercury concentration in the standard gas. Summary of the invention

[0005] The purpose of the present invention is to overcome the disadvantages of the prior art and provide a high-precision mercury standard gas generation system and method, which can generate mercury standard gas with high precision.

[0006] To achieve the above object, the present invention discloses a high-precision mercury standard gas generation system, including a carrier gas supply module, a mercury source evaporation module, a thermal dilution mixing module, a sonic pinhole constant current module and an intelligent control system;

[0007] The outlet of the carrier gas supply module is connected to the inlet of the mercury source evaporation module and the inlet of the thermal dilution mixing module, the outlet of the mercury source evaporation module is connected to the inlet of the sonic small hole constant current module, and the outlet of the sonic small hole constant current module is connected to the inlet of the thermal dilution mixing module;

[0008] The intelligent control system is connected with the carrier gas supply module and the thermal dilution mixing module.

[0009] The further improvement of the high-precision mercury standard gas generation system of the present invention is:

[0010] Furthermore, the carrier gas supply module includes an inert gas source and a first pressure regulating valve, wherein the outlet of the inert gas source is connected to the inlet of the first pressure regulating valve and the inlet of the thermal dilution mixing module, the outlet of the first pressure regulating valve is connected to the inlet of the mercury source evaporation module, and the intelligent control system is connected to the first pressure regulating valve and the inert gas source.

[0011] Furthermore, the thermal dilution mixing module includes a thermal dilution ejector, a second pressure regulating valve and a flow regulating valve, the outlet of the inert gas source is connected to the inlet of the thermal dilution ejector via the second pressure regulating valve and the flow regulating valve in sequence, the outlet of the sonic orifice constant current module is connected to the inlet of the thermal dilution ejector, and the intelligent control system is connected to the thermal dilution ejector, the second pressure regulating valve and the flow regulating valve.

[0012] Furthermore, the sonic orifice in the sonic orifice constant current module is made of stainless steel.

[0013] Furthermore, the surface of the sonic hole is provided with an inert coating.

[0014] Furthermore, the thermal dilution ejector is made of stainless steel.

[0015] Furthermore, the surface of the thermal dilution ejector is provided with an inert coating.

[0016] Furthermore, the mercury source evaporation module is connected to the sonic orifice constant current module through a connecting pipe.

[0017] Furthermore, the connecting pipe is made of polytetrafluoroethylene / stainless steel with an added inert coating.

[0018] The invention discloses a high-precision mercury standard gas generation method, which is based on a high-precision mercury standard gas generation system. The high-precision mercury standard gas generation system comprises a carrier gas supply module, a mercury source evaporation module, a thermal dilution mixing module, a sonic small hole constant current module and an intelligent control system; the outlet of the carrier gas supply module is connected with the inlet of the mercury source evaporation module and the inlet of the thermal dilution mixing module, the outlet of the mercury source evaporation module is connected with the inlet of the sonic small hole constant current module, and the outlet of the sonic small hole constant current module is connected with the inlet of the thermal dilution mixing module; the intelligent control system is connected with the carrier gas supply module and the thermal dilution mixing module,

[0019] Specifically, the high-precision mercury standard gas generation method comprises the following steps:

[0020] Under the control of the intelligent control system, the constant-flow and constant-pressure inert gas output by the carrier gas supply module carries the mercury vapor generated by the mercury source evaporation module and enters the sonic pinhole constant-flow module. Under the constant-flow action of the sonic pinhole and the ejection action of the thermal dilution ejector, the mercury-containing gas flow enters the thermal dilution ejector at a constant flow rate and pressure to mix and dilute with the dilution gas to form the required high-precision mercury standard gas.

[0021] The present invention has the following beneficial effects:

[0022] During specific operation of the high-precision mercury standard gas generating system and method described in the present invention, under the regulation of the intelligent control system, the inert carrier gas enters the mercury source evaporation module at a constant pressure. Under the constant pressure and constant current action of the sonic pinhole constant current module, the influence of the pressure and flow state of the subsequent pipeline on the mercury vapor concentration is eliminated to a great extent. In addition, the mercury vapor is accurately diluted by the thermal dilution mixing module to obtain mercury standard gas with extremely high precision. It should be noted that the present invention adopts high-precision mercury standard gas generation technology, which can stably generate high-precision mercury standard gas, overcoming the problems of poor stability of traditional technology and great influence of subsequent pipeline on the concentration of standard gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 It is a schematic diagram of the system of the present invention;

[0025] Among them, 1 is a carrier gas supply module, 11 is an inert gas source, 12 is a first pressure regulating valve, 2 is a mercury source evaporation module, 3 is a sonic pinhole constant flow module, 4 is a thermal dilution mixing module, 41 is a second pressure regulating valve, 42 is a flow regulating valve, 43 is a thermal dilution ejector, 5 is a connecting pipeline, and 6 is an intelligent control system. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0028] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0029] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0030] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0031] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0034] Embodiment 1

[0035] refer to Figure 1The high-precision mercury standard gas generation system of the present invention includes a carrier gas supply module 1, a mercury source evaporation module 2, a thermal dilution mixing module 4, a sonic pinhole constant current module 3 and an intelligent control system 6; the outlet of the carrier gas supply module 1 is connected to the inlet of the mercury source evaporation module 2 and the inlet of the thermal dilution mixing module 4, the outlet of the mercury source evaporation module 2 is connected to the inlet of the sonic pinhole constant current module 3, and the outlet of the sonic pinhole constant current module 3 is connected to the inlet of the thermal dilution mixing module 4; the intelligent control system 6 is connected to the carrier gas supply module 1 and the thermal dilution mixing module 4.

[0036] The high-precision mercury standard gas generation method of the present invention is based on a high-precision mercury standard gas generation system and comprises the following steps:

[0037] Under the control of the intelligent control system 6, the constant flow and constant pressure inert gas output by the carrier gas supply module 1 carries the mercury vapor generated by the mercury source evaporation module 2 and enters the sonic orifice constant flow module 3. Under the constant flow effect of the sonic orifice and the ejection effect of the thermal dilution ejector 43, the mercury-containing gas flow enters the thermal dilution ejector 43 at a constant flow rate and pressure to mix and dilute with the dilution gas to form the required high-precision mercury standard gas.

[0038] Embodiment 2

[0039] refer to Figure 1 The high-precision mercury standard gas generation system of the present invention comprises a carrier gas supply module 1, a mercury source evaporation module 2, a sonic pinhole constant current module 3, a thermal dilution mixing module 4, a connecting pipeline 5 and an intelligent control system 6;

[0040] The outlet of the carrier gas supply module 1 is connected to the inlet of the mercury source evaporation module 2 and the inlet of the thermal dilution mixing module 4, the outlet of the mercury source evaporation module 2 is connected to the inlet of the sonic orifice constant current module 3, and the outlet of the sonic orifice constant current module 3 is connected to the inlet of the thermal dilution mixing module 4.

[0041] As an implementation mode of the present invention, in this embodiment, the carrier gas supply module 1 includes an inert gas source 11 and a first pressure regulating valve 12, wherein the outlet of the inert gas source 11 is connected to the inlet of the first pressure regulating valve 12 and the inlet of the thermal dilution mixing module 4, and the outlet of the first pressure regulating valve 12 is connected to the inlet of the mercury source evaporation module 2. The intelligent control system 6 is connected to the control end of the carrier gas supply module 1, the control end of the mercury source evaporation module 2, and the control end of the thermal dilution mixing module 4.

[0042] As an embodiment of the present invention, the thermal dilution mixing module 4 includes a thermal dilution ejector 43, a second pressure regulating valve 41 and a flow regulating valve 42. The outlet of the inert gas source 11 is connected to the inlet of the thermal dilution ejector 43 via the second pressure regulating valve 41 and the flow regulating valve 42 in sequence, and the outlet of the sonic orifice constant current module 3 is connected to the inlet of the thermal dilution ejector 43.

[0043] As an implementation mode of the present invention, the intelligent control system 6 is connected to the first pressure regulating valve 12 , the second pressure regulating valve 41 , the mercury source evaporation module 2 and the flow regulating valve 42 .

[0044] As an implementation mode of the present invention, it should be noted that the intelligent control system 6 is connected to the first pressure regulating valve 12 to ensure that the required constant pressure carrier gas is provided to the system.

[0045] As an implementation mode of the present invention, it should be noted that the intelligent control system 6 is connected to the mercury source evaporation module 2, and the mercury source evaporation module 2 controls the evaporation rate of the mercury source by accurately adjusting the temperature.

[0046] As an embodiment of the present invention, the sonic orifice constant flow module 3 selects sonic orifices with different flow rates according to the standard gas flow demand, and controls the mercury-containing gas flow entering the thermal dilution mixing module 4 through the constant flow effect of the sonic orifice.

[0047] As an embodiment of the present invention, the sonic orifice in the sonic orifice constant current module 3 is made of stainless steel or other high-strength metals and alloys, and an inert coating such as quartz / polytetrafluoroethylene is added to its surface to reduce the adsorption of mercury.

[0048] As an embodiment of the present invention, when the thermal dilution mixing module 4 is in operation, under the effect of the high-pressure inert gas injection, a constant flow of mercury-containing gas is mixed with the inert dilution gas in the thermal dilution injector 43 to produce the required mercury standard gas.

[0049] As an embodiment of the present invention, the thermal dilution ejector 43 is made of stainless steel or other high-strength metals and alloys, and an inert coating such as quartz / polytetrafluoroethylene is added to its surface to reduce the adsorption of mercury.

[0050] As an embodiment of the present invention, the connecting pipe 5 is made of polytetrafluoroethylene / stainless steel with an inert coating or other high-strength metal, and has a heating and heat preservation function to reduce the adsorption of mercury by the pipeline and the dilution and condensation of mercury.

[0051] As an embodiment of the present invention, the intelligent control system 6 can adjust the corresponding control parameters of the carrier gas supply module 1, the mercury source evaporation module 2 and the thermal dilution mixing module 4 according to the required mercury standard gas flow and concentration requirements to generate the required high-precision mercury standard gas.

[0052] The high-precision mercury standard gas generation method of the present invention is implemented based on the high-precision mercury standard gas generation system, which includes a carrier gas supply module 1, a mercury source evaporation module 2, a sonic pinhole constant current module 3, a thermal dilution mixing module 4, a connecting pipeline 5 and an intelligent control system 6; the outlet of the carrier gas supply module 1 is connected to the inlet of the mercury source evaporation module 2 and the inlet of the thermal dilution mixing module 4, the outlet of the mercury source evaporation module 2 is connected to the inlet of the sonic pinhole constant current module 3, and the outlet of the sonic pinhole constant current module 3 is connected to the inlet of the thermal dilution mixing module 4; the carrier gas supply module 1 includes an inert gas source 11 and a first pressure regulating valve 12, wherein the outlet of the inert gas source 11 is connected to the inlet of the first pressure regulating valve 12 and the inlet of the thermal dilution mixing module 4, and the outlet of the first pressure regulating valve 12 is connected to the inlet of the mercury source evaporation module 2. The intelligent control system 6 is connected to the control end of the carrier gas supply module 1, the control end of the mercury source evaporation module 2 and the control end of the thermal dilution mixing module 4; the thermal dilution mixing module 4 includes a thermal dilution ejector 43, a second pressure regulating valve 41 and a flow regulating valve 42, the outlet of the inert gas source 11 is connected to the inlet of the thermal dilution ejector 43 via the second pressure regulating valve 41 and the flow regulating valve 42 in sequence, and the outlet of the sonic orifice constant current module 3 is connected to the inlet of the thermal dilution ejector 43; the intelligent control system 6 is connected to the first pressure regulating valve 12, the second pressure regulating valve 41, the mercury source evaporation module 2 and the flow regulating valve 42.

[0053] The high-precision mercury standard gas generation method comprises the following steps:

[0054] According to the set standard gas demand, under the control of the intelligent control system 6, the constant flow and constant pressure inert gas output by the gas supply module 1 carries the mercury vapor generated by the mercury source evaporation module 2 into the sonic orifice constant flow module 3. Under the constant flow effect of the sonic orifice and the ejection effect of the thermal dilution ejector 43, the mercury-containing gas flow enters the thermal dilution ejector 43 at a constant flow rate and pressure to mix and dilute with the dilution gas to form the required high-precision mercury standard gas.

[0055] The division of modules in the embodiments of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional module in each embodiment of the present application may be integrated into a processor, or may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of software functional modules.

[0056] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0057] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0058] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A high-precision mercury standard gas generation system, characterized in that: It comprises a carrier gas supply module (1), a mercury source evaporation module (2), a thermal dilution mixing module (4), a sonic small hole constant flow module (3) and an intelligent control system (6); The outlet of the carrier gas supply module (1) is connected to the inlet of the mercury source evaporation module (2) and the inlet of the thermal dilution mixing module (4); the outlet of the mercury source evaporation module (2) is connected to the inlet of the sonic small hole constant current module (3); and the outlet of the sonic small hole constant current module (3) is connected to the inlet of the thermal dilution mixing module (4); The intelligent control system (6) is connected to the carrier gas supply module (1) and the thermal dilution mixing module (4).

2. The high-precision mercury standard gas generation system according to claim 1, characterized in that: The carrier gas supply module (1) comprises an inert gas source (11) and a first pressure regulating valve (12), wherein the outlet of the inert gas source (11) is connected to the inlet of the first pressure regulating valve (12) and the inlet of the thermal dilution mixing module (4), the outlet of the first pressure regulating valve (12) is connected to the inlet of the mercury source evaporation module (2), and the intelligent control system (6) is connected to the first pressure regulating valve (12) and the inert gas source (11).

3. The high-precision mercury standard gas generation system according to claim 1, characterized in that: The thermal dilution mixing module (4) comprises a thermal dilution ejector (43), a second pressure regulating valve (41) and a flow regulating valve (42); the outlet of the inert gas source (11) is connected to the inlet of the thermal dilution ejector (43) via the second pressure regulating valve (41) and the flow regulating valve (42) in sequence; the outlet of the sonic orifice constant current module (3) is connected to the inlet of the thermal dilution ejector (43); and the intelligent control system (6) is connected to the thermal dilution ejector (43), the second pressure regulating valve (41) and the flow regulating valve (42).

4. The high-precision mercury standard gas generation system according to claim 1, characterized in that: The sonic orifice in the sonic orifice constant current module (3) is made of stainless steel.

5. The high-precision mercury standard gas generation system according to claim 4, characterized in that: The surface of the sonic orifice is provided with an inert coating.

6. The high-precision mercury standard gas generation system according to claim 1, characterized in that: The thermal dilution ejector (43) is made of stainless steel.

7. The high-precision mercury standard gas generation system according to claim 6, characterized in that: The surface of the thermal dilution ejector (43) is provided with an inert coating.

8. The high-precision mercury standard gas generation system according to claim 1, characterized in that: The mercury source evaporation module (2) is connected to the sonic orifice constant current module (3) via a connecting pipe (5).

9. The high-precision mercury standard gas generation system according to claim 8, characterized in that: The connecting pipe (5) is made of polytetrafluoroethylene / stainless steel with an inert coating added.

10. A method for generating high-precision mercury standard gas, characterized in that: The high-precision mercury standard gas generation system according to claim 1 comprises the following steps: Under the control of the intelligent control system (6), the constant flow and constant pressure inert gas output by the carrier gas supply module (1) carries the mercury vapor generated by the mercury source evaporation module (2) and enters the sonic orifice constant flow module (3). Under the constant flow effect of the sonic orifice and the ejection effect of the thermal dilution ejector (43), the mercury-containing gas flow enters the thermal dilution ejector (43) at a constant flow rate and pressure to be mixed and diluted with the dilution gas to form the required high-precision mercury standard gas.

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