WO2018231047A1

WO2018231047A1 - System and method for measuring mercury in a hydrocarbon stream

Info

Publication number: WO2018231047A1
Application number: PCT/MY2018/050041
Authority: WO
Inventors: Tengku M Uzaini TENGKU MAT; Ahmad Syukri Na’im M HANAFIAH; Nor Hafizah YASIN; Sharizal MOHD AZAM SHAH WONG
Original assignee: Petroliam Nasional Bhd Petronas
Current assignee: Petroliam Nasional Bhd Petronas
Priority date: 2017-06-15
Filing date: 2018-06-13
Publication date: 2018-12-20
Anticipated expiration: 2019-12-15
Also published as: MY198938A

Abstract

System and method for measuring mercury in a hydrocarbon stream. The system includes: a wave generator configured to emit microwaves; a receptacle configured to hold a catalyst; a fluid transporter configured to allow the hydrocarbon stream to be in fluid communication with the receptacle that is holding the catalyst; and a 10 waveguide disposed between the wave generator and the receptacle, the waveguide configured to channel the emitted microwaves to the catalyst such that the catalyst absorbs the microwaves to generate heat for converting mercury in the hydrocarbon stream into elemental mercury. The catalyst can also facilitate vaporization and cracking of complex hydrocarbon chains in the hydrocarbon stream to simpler 15 hydrocarbon chains. An additional catalyst can be provided to trap or adsorb the simpler hydrocarbon chains and its pyrolized product from the hydrocarbon stream.

Description

SYSTEM AND METHOD FOR MEASURING MERCURY IN A HYDROCARBON STREAM

FIELD OF INVENTION

[001] The invention relates to systems and methods for measuring mercury in a hydrocarbon stream.

BACKGROUND

[002] Mercury is a naturally occurring impurity found in hydrocarbons. Mercury causes detrimental effects to process equipment and poses a health hazard to personnel. Measurement of mercury in hydrocarbons is therefore an important aspect of mitigating the challenges associated with mercury. However, measuring mercury in liquid hydrocarbons is challenging due to the complex matrix of hydrocarbons.

[003] The three main groups of mercury are elemental mercury (Hg^°), organic mercury and inorganic mercury. Mercury is commonly detected via spectroscopy technology in elemental form ; therefore the conversion of all mercury species to elemental mercury is necessary. At temperatures of 700°C - 800 °C and above, all mercury species is converted to elemental mercury. There are currently two extensively used techniques for converting all mercury species to elemental mercury: thermal conversion technique and wet chemistry technique. [004] In the wet chemistry technique, oxidized mercury is converted to elemental mercury using a liquid reducing agent (e.g. SnCI₂) prior to entering the detector unit. The thermal conversion method requires that the sample is in gaseous form and channeled through an adsorbent where mercury species will be trapped/amalgamated at elevated temperatures. This adsorbent (comprising noble metals such as gold or platinum) is then heated to high temperatures (700°C - 800 °C) where mercury species are released and converted to elemental mercury and swept by a carrier gas to the detector. Measurement of mercury is normally done at a set wavelength of 253.7 nm. The thermal conversion technique is preferred to the wet chemistry method simply because it is does not involve any reagents, is more reliable, simple and suits the requirement for online analyzer applications. [005] There are currently a number of mercury detection methods that are designed based on the thermal conversion technique either by the use of a combustion method (0₂ rich) or a pyrolize method (0₂ deficient). One example method involves the use of a heating chamber (i.e. vaporizer; 400°C) to convert liquid samples to gaseous form, trapping mercury with an adsorbent (a "mercury trap") at elevated temperatures and desorption at high temperatures. Desorption of mercury at high temperature (700°C - 800 °C) converts all mercury species to elemental mercury (Hg°). This is followed by measurement of mercury concentration via a detector. [006] Another setup involves the combustion of liquid hydrocarbon at high temperatures (700°C - 800°C) to gaseous form which also converts all mercury species to elemental mercury (Hg°) and oxidized form. This is followed by trapping of the gaseous hydrocarbon with a suitable material (i.e. hydrocarbon adsorbent and catalyst) to convert the combustion products and allow elemental mercury to pass through the hydrocarbon adsorbent to be trapped by a downstream mercury adsorbent. Next, the mercury is desorbed and channeled to a mercury detector for measurement. This setup is simpler than the wet chemistry method and suitable for laboratory bench applications. For this conventional heating method at lower vaporization temperature, there is a possibility of condensation of the hydrocarbon matrix that can affect analyser robustness and accuracy (either by reducing the lifespan of downstream component, re-combination with Hg species, or for the combustion technique - risk of fire if installed online at a hydrocarbon rich environment). Furthermore, the analysis cycle for the conventional heating method can be more than 10 minutes in order to ensure complete combustion and conversion. Moreover, there is a need to use several catalysts which also adds to the cost of running the analyser.

[007] A need therefore exists to provide systems and methods for measuring mercury in a hydrocarbon stream that seeks to address at least one of the abovementioned problems.

SUMMARY

[008] According to a first aspect, there is provided a system for measuring mercury in a hydrocarbon stream, comprising: a wave generator configured to emit microwaves; a receptacle configured to hold a catalyst; a fluid transporter configured to allow the hydrocarbon stream to be in fluid communication with the receptacle that is holding the catalyst; and a waveguide disposed between the wave generator and the receptacle, the waveguide configured to channel the emitted microwaves to the catalyst such that the catalyst absorbs the microwaves to generate heat for converting mercury in the hydrocarbon stream into elemental mercury. The catalyst can also facilitate vaporization and cracking of complex hydrocarbon chains in the hydrocarbon stream to simpler hydrocarbon chains. An additional catalyst can be provided to trap or adsorb the simpler hydrocarbon chains and its pyrolized product from the hydrocarbon stream . [009] According to a second aspect, there is provided a method for measuring mercury in a hydrocarbon stream, comprising: emitting microwaves from a wave generator; providing a receptacle that is configured to hold a catalyst; passing the hydrocarbon stream to the receptacle such that the hydrocarbon stream is in fluid communication with the receptacle that is holding the catalyst; and using a waveguide that is disposed between the wave generator and the receptacle to channel the emitted microwaves to the catalyst such that the catalyst absorbs the microwaves to generate heat for converting mercury in the hydrocarbon stream into elemental mercury. The catalyst can also facilitate vaporization and cracking of complex hydrocarbon chains in the hydrocarbon stream to simpler hydrocarbon chains. An additional catalyst can be provided to trap or adsorb the simpler hydrocarbon chains and its pyrolized product from the hydrocarbon stream.

BRIEF DESCRIPTION OF THE DRAWINGS [0010] Example embodiments of the invention will be better understood and readily apparent to one of ordinary skill in the art from the following written description, by way of example only, and in conjunction with the drawings, in which:

[0011 ] Figure 1 is a schematic of a system for measuring mercury in a hydrocarbon stream, according to an embodiment of the invention.

[0012] Figures 2A to 2D illustrate an operation sequence of the system for measuring mercury in a hydrocarbon stream, according to an embodiment of the invention. [0013] Figure 3 is a flow chart 300 illustrating a method for measuring mercury in a hydrocarbon stream, according to an embodiment of the invention.

[0014] Figures 4 to 10 illustrate the various sequences of a start-up cycle and sampling/analysis cycle, according to an embodiment of the invention.

DETAILED DESCRIPTION

[0015] Embodiments of the invention will be described with reference to the drawings. Like reference numerals and characters in the drawings refer to like elements or equivalents.

[0016] Embodiments of the invention seek to provide systems and methods for measuring mercury in a hydrocarbon stream (i.e. sample) using microwave assisted thermal pyrolysis. The hydrocarbon stream may comprise natural gas, condensate, crude oil and/or refined oil products. Microwaves are directed towards one or more catalysts, and the one or more catalysts absorb the microwaves to generate heat for converting various species of mercury in the hydrocarbon stream into its elemental form without recombination back to its original species. The elemental mercury can then be detected via spectroscopy technology. The one or more catalysts can also vaporize and crack complex hydrocarbon chains in the hydrocarbon stream to simpler hydrocarbon chains. The one or more catalysts can further trap or even eliminate pyrolysis hydrocarbon products, e.g. soot, particulate, carbon products that may affect the accuracy of the mercury detector.

[0017] Figure 1 is a schematic of a system 100 for measuring mercury in a hydrocarbon stream, according to an embodiment of the invention. The system 100 includes the following components: a wave generator 102 that is configured to emit microwaves, a receptacle 104 that is configured to hold a catalyst 105a, a fluid transporter 106 that is configured to allow the hydrocarbon stream to be in fluid communication with the receptacle 104 that is holding the catalyst 105a, and a waveguide 108 that is disposed between the wave generator 102 and the receptacle 104. The waveguide 108 is configured to channel the emitted microwaves to the catalyst 105a such that the catalyst 105a absorbs the microwaves to generate heat (at least about 800°C) for converting mercury in the hydrocarbon stream into elemental mercury. In other words, the catalyst converts the radiation energy of the microwaves into heat and transfers the heat to the sample (i.e. hydrocarbon stream with mercury) for pyrolysis.

[0018] In addition, the catalyst 105a can absorb the microwaves to generate heat to at least partially crack complex hydrocarbon molecules in the hydrocarbon stream into simpler hydrocarbon molecules. The receptacle 104 can be configured to hold an additional catalyst 105b. The additional catalyst 105b can adsorb the simpler hydrocarbon molecules. In other words, the two catalysts (i.e. the catalyst 105a and the additional catalyst 105b) serve different functions while being contained in the single receptacle 104.

[0019] The wave generator 102 may include a magnetron that is capable of generating the microwaves with a power range between 800 to 1500 Watts. The wave generator 102, receptacle 104 and waveguide 108 are preferably positioned and aligned in a specific fashion so as to optimize the absorption of the microwave energy by the catalyst 105a. The wave generator 102, receptacle 104 and waveguide 108 may be disposed in an enclosure 107 at a pressure of about 1 atm.

[0020] The fluid transporter 106 may include an injector with associated ports and tubing that are inert to mercury and transparent to microwaves (does not absorb microwaves). A carrier gas (e.g. Nitrogen, > 95% purity) may be used to transport the hydrocarbon stream (i.e. sample). A pressure regulator may be used to regulate the pressure from a carrier gas source (e.g. gas cylinder) to an injector port, i.e. high to low pressure.

[0021 ] The catalyst 105a includes a mixture of relatively high dissipation factor materials (e.g. carbon-based materials) to accelerate the heating rate. In this context, a substance having a dissipation factor of at least 0.30, preferably 0.35, is considered relatively high. The catalyst 105a may include silicon carbide (SiC) and carbon (C), with a SiC:C ratio ranging from 1 :0 to 1 :1 . The SiC may include a-SiC or β-SiC, or other structure as well as crystalline and amorphous forms. The catalyst 105a absorbs microwaves to generate heat sufficient to convert all target analyte (i.e. mercury) species to elemental form as well as to crack portions of complex hydrocarbons molecules inside the sample matrix (condensate and crude oil range) into simpler hydrocarbons molecules.

[0022] The additional catalyst 105b includes a substance derived from a polymer- based material, e.g. 2, 6-diphenylene-oxide. The additional catalyst 105b adsorbs the cracked hydrocarbons to prevent them from entering the downstream region. However, the additional catalyst 105b does not adsorb elemental mercury.

[0023] The receptacle 104 can include a separator 1 10 to physically separate the catalyst 105a and the additional catalyst 105b when they are being held in the receptacle 104. The catalyst 105a and the additional catalyst 105b are separated to avoid decomposition of the polymer-based material of the additional catalyst 105b due to localized high temperatures at the catalyst 105a. [0024] The receptacle 104 can be positioned within a housing (not shown) that includes walls, such that the housing surrounds / encloses at least a portion of the receptacle 104. The walls of the housing are configured to reflect a portion of the emitted microwaves such that standing waves are formed in the receptacle 104 at a resonant frequency to facilitate the generation of heat by the catalyst 105a held in the receptacle 104. The receptacle 104 is preferably constructed from a material with a high melting point (about 1700°C), low loss-tangent, transparency to microwave radiation (does not absorb microwaves) and inertness to mercury, e.g. quartz.

[0025] In one implementation, the system 100 may further include a mercury trap 1 12 disposed downstream relative to the receptacle 104. The system 100 may further include a detector 1 14 in fluid communication with the mercury trap 1 12 for detecting mercury being desorbed therefrom. The mercury trap 1 12 is able to capture mercury vapour via amalgamation while allowing other substances (e.g. carrier gas, hydrocarbon vapour) to pass through. The mercury trap 1 12 can be heated to about 700°C to release the trapped mercury to the detector 1 14. The detector 1 14 can measure mercury content down to trace levels, e.g. Spectroscopy and other detectors capable of detecting mercury.

[0026] In an alternative implementation (not shown in Figure 1 ), the system 100 may further include at least two mercury traps disposed downstream relative to the receptacle 104. At a particular point in time, at least one trap operates in an adsorption mode for adsorbing the elemental mercury while at least one other trap operates in a desorption mode for releasing the elemental mercury. The system 100 may further include a detector 1 14 in fluid communication with the trap that is operating in the desorption mode for detecting mercury being desorbed therefrom. The at least two mercury traps are configured to alternate between the adsorption mode and the desorption mode to enable measurement of mercury in the hydrocarbon stream.

[0027] Figures 2A to 2D illustrate an operation sequence of the system 100 for measuring mercury in a hydrocarbon stream, according to an embodiment of the invention.

[0028] As shown in Figure 2A, during the first phase (injection), a sample is introduced into the system 100 at the fluid transporter 106. The sample is transported directly by the fluid transporter 106 to the receptacle 104 that is holding the catalyst 105a. The sample can be manually injected or automatically injected via a sample injection system. In either case, a carrier gas is introduced into the system 100 at the fluid transporter 106. The carrier gas continuously flows during the entire operation (i.e. the first phase and subsequent phases). During the first phase, the wave generator 102 is inactive.

[0029] As shown in Figure 2B, during the second phase (heating), the wave generator 102 is activated at around 800 to 1500W. The catalyst 105a is heated up and the heat is transferred to the deposited sample. The sample is heated up to about 800°C and above and the sample matrix is vaporized. At this juncture, mercury species in the sample matrix is converted to elemental mercury, and the complex hydrocarbon is hydrocracked into simpler hydrocarbons.

[0030] As shown in Figure 2C, during the third phase (adsorption), the vaporized sample matrix is carried through the additional catalyst 105b (i.e. hydrocarbon adsorbent). Hydrocarbon molecules are trapped by the hydrocarbon adsorbent while mercury vapour passes through. Still referring to Figure 2C, during the fourth phase (trapping and desorption), the mercury vapour is trapped by the mercury trap 1 12. Trapping time is about 3 to 5 minutes to ensure entrapment of all mercury vapour. Thereafter, the mercury trap 1 12 can be heated to about 700°C to release the trapped mercury to the detector 1 14.

[0031 ] As shown in Figure 2D, during the fifth phase (detection), the released mercury is transported by the carrier gas and flows to the downstream components such as the detector 1 14. The detector 1 14 can measure mercury content down to trace levels, e.g. Spectroscopy and other detectors capable of detecting mercury. [0032] Figure 3 is a flow chart 300 illustrating a method for measuring mercury in a hydrocarbon stream, according to an embodiment of the invention. The method 300 includes a step 302 of emitting microwaves from a wave generator, a step 304 of providing a receptacle that is configured to hold a catalyst, a step 306 of passing the hydrocarbon stream to the receptacle such that the hydrocarbon stream is in fluid communication with the receptacle that is holding the catalyst, and a step 308 of using a waveguide that is disposed between the wave generator and the receptacle to channel the emitted microwaves to the catalyst such that the catalyst absorbs the microwaves to generate heat for converting mercury in the hydrocarbon stream into elemental mercury.

[0033] The catalyst absorbs the microwaves to generate heat to also at least partially crack complex hydrocarbon molecules in the hydrocarbon stream into simpler hydrocarbon molecules.

[0034] The receptacle is configured to hold an additional catalyst that can adsorb the hydrocarbon molecules. The additional catalyst can adsorb both complex and simple hydrocarbon molecules. The catalyst and the additional catalyst do not capture elemental mercury. Preferably, the catalyst and the additional catalyst are physically separated in the receptacle. The receptacle may be located within a housing that has walls that are configured to reflect a portion of the emitted microwaves such that standing waves are formed in the receptacle at a resonant frequency to facilitate the generation of heat by the catalyst held in the receptacle. [0035] The catalyst includes a substance having a dissipation factor of at least 0.30. The catalyst may include silicon carbide (SiC) and carbon (C), with a SiC:C ratio ranging from 1 :0 to 1 :1 . The SiC may include a-SiC or β-SiC. The additional catalyst includes a substance derived from a polymer-based material, e.g. 2, 6-diphenylene- oxide.

[0036] The method may further include the step of providing at least two mercury traps disposed downstream relative to the receptacle, in which at least one trap operates in an adsorption mode for adsorbing the elemental mercury while at least one other trap operates in a desorption mode for releasing the elemental mercury. [0037] The method may further include the step of providing a detector in fluid communication with the trap that is operating in the desorption mode for detecting mercury being desorbed therefrom. [0038] The method may further include the step of configuring at least two mercury traps to alternate between the adsorption mode and the desorption mode to enable measurement of mercury in the hydrocarbon stream.

[0039] In an example embodiment, the system 100 can be configured to operate in two different operating cycles: a start-up cycle and a sampling/analysis cycle. The following description, in conjunction with Figures 4 to 15, describes the various sequences of the start-up cycle and sampling/analysis cycle.

[0040] The start-up cycle comprises one sequence, Sequence 0, for conditioning the system. A stream of carrier gas provides means to translocate the sample through the entirety of the system. Sequence 0 can be conducted for >30 minutes during initial start-up prior to initiating the sampling/analysis cycle. With reference to Figure 4, a steady flow of carrier gas (e.g. N₂; >95% purity) is introduced to the microwave system 402, through 8-port valve 404 (via sample loop 2) and is sent to sample waste 406 to purge the catalyst and line from presence of 0₂ and other impurities. The mercury traps of Sample Loop 1 (i.e. trap 408a) and Sample Loop 2 (i.e. trap 408b) are on standby. The carrier gas passes through Sample Loop 1 towards mercury detector 410. The microwave system 402 is 'off during Sequence 0. [0041 ] After the start-up cycle is completed, the sampling/analysis cycle can be initiated. By default, the stream of carrier gas is always flowing during the sampling/analysis cycle. With reference to Figure 5, in the first sequence of the sampling/analysis cycle (Sequence 1 ), the sample is first introduced to the system. The stream of carrier gas is always flowing for catalyst conditioning. In particular, a finite volume between 0.1 to 0.5 mL of a hydrocarbon sample is injected onto Catalyst 1 +2 module 502a while microwave system 502 is 'off. The carrier gas (N₂) continuously flows into microwave system 502 through Catalyst 1 +2 module 502a, continues towards 8-port valve 504 (via sample loop 2) and proceeds to sample waste 506. In Sequence 1 , any naturally flashed gas from the sample is transported to the gold coated silica trap 508b and Hg is trapped while the gas passes through to Sample Waste. There is a possibility that a part of the hydrocarbon sample may vaporize upon injection (e.g. due to temperature/pressure drop) and this vapor carries Hg. As the vapor is carried by the carrier gas to waste, the Hg in the vapor is trapped at mercury trap 508b and the vapor passes through to sample waste. Thus, no Hg escapes from analysis. Simultaneously, the carrier gas passes through Sample Loop 1 towards mercury detector 510.

[0042] With reference to Figure 6, in the second sequence of the sampling/analysis cycle (Sequence 2), injection of hydrocarbon sample ceases and 800 to 1500 W of microwave energy is supplied to the catalyst via the microwave system 602 while the carrier gas flows through Catalyst 1 +2 module 602a to Sample Loop 2 and continues to sample waste 606. Catalyst 1 +2 module 602a adsorbs the microwave energy and converts the energy into heat resulting in a rapid temperature ramp up to 800 - 1000°C. The heat which is transferred to the sample converts all mercury species to elemental mercury while the catalyst cracks the hydrocarbon chains in the sample matrix and traps the pyrolized product (i.e. soot, particulate). The elemental mercury flows towards 8-port valve 604 and is adsorbed (i.e. amalgamated) onto mercury trap 608b (Sample Loop 2) while the spent sample which is not trapped by Catalyst 1 +2 module 602a is discarded to sample waste 606. Simultaneously, the mercury trap 608a for Sample Loop 1 is on standby. [0043] With reference to Figure 7, in the third sequence of the sampling/analysis cycle (Sequence 3), microwave system 702 is switched 'off and flow of N₂ may enter the microwave system to externally cool the system . The 8-port valve 704 switches and the mercury trap 708b at Sample Loop 2 undergoes desorption to release mercury which is pushed by the carrier gas to a mercury trap (i.e. double amalgamation) located in the mercury detector 710. The mercury trap 708b is heated to desorb the mercury and is pushed by the carrier gas to the mercury detector 710 for measurement. Simultaneously, mercury trap 708a for Sample Loop 1 is on standby to receive the next sample. The mercury trap of the mercury detector 710 adsorbs the mercury and channels the remaining mercury-free gas to waste. While the microwave system 702 is Off, a finite volume between 0.1 to 0.5 mL of hydrocarbon sample is injected onto Catalyst 1 +2 module 702a.

[0044] With reference to Figure 8, in the fourth sequence of the sampling/analysis cycle (Sequence 4), injection of hydrocarbon sample ceases and 800 to 1500 W of microwave energy is supplied to the catalyst via the microwave system 802 while carrier gas flows through Catalyst 1 +2 module 802a to Sample Loop 1 and continues to sample waste 806. Catalyst 1 +2 module 802a adsorbs the microwave energy and converts the energy into heat resulting in a rapid temperature ramp up to 800 - 1000°C. The heat which is transferred to the sample converts all mercury species to elemental mercury while the catalyst cracks the hydrocarbon chains in the sample matrix and traps the pyrolized product (i.e. soot, particulate). The elemental mercury flows towards 8-port valve 804 and is adsorbed (i.e. amalgamated) onto a mercury trap 808a (Sample Loop 1 ) while the spent sample which is not trapped by Catalyst 1 +2 module 802a is discarded to sample waste 806. At the same time, the mercury trap 808b at Sample Loop 2 is cooled using an external flow of N₂. No carrier gas passes through this trap.

[0045] With reference to Figure 9, in the fifth sequence of the sampling/analysis cycle (Sequence 5), microwave system 902 is switched 'off and flow of N₂ may enter the microwave system to externally cool the system. The 8-port valve 904 switches and the mercury trap 908a at Sample Loop 1 undergoes desorption to release mercury which is pushed by the carrier gas to the mercury trap (i.e. double amalgamation) located in the mercury detector 910. The mercury trap 908a is heated to desorb the mercury and is pushed by the carrier gas to the mercury detector 910 for measurement. The mercury trap 908b for Sample Loop 2 has completed its cooling phase and is on standby to receive the next sample. The mercury trap of the mercury detector 910 adsorbs the mercury and channels the remaining mercury-free gas to waste. While microwave system 902 is Off, a finite volume between 0.1 to 0.5 mL of hydrocarbon sample is injected onto Catalyst 1 +2 module 902a.

[0046] With reference to Figure 10, in the sixth sequence of the sampling/analysis cycle (Sequence 6), injection of hydrocarbon sample ceases and 800 to 1500 W of microwave energy is supplied to the catalyst via the microwave system 1002 while carrier gas flows through Catalyst 1 +2 module 1002a to Sample Loop 2 and continues to sample waste 1006. Catalyst 1 +2 module 1002a adsorbs the microwave energy and converts the energy into heat resulting in a rapid temperature ramp up to 800 - 1000°C. The heat which is transferred to the sample converts all mercury species to elemental mercury while the catalyst cracks the hydrocarbon chains in the sample matrix and traps the pyrolized product (i.e. soot, particulate). The elemental mercury flows towards 8-port valve 1004 and is adsorbed (i.e. amalgamated) onto a mercury trap 1008b (Sample Loop 2) while the spent sample which is not trapped by Catalyst 1 +2 module 1002a is discarded to sample waste 1006. At the same time, the mercury trap 1008a at Sample Loop 1 is cooled using an external flow of N₂. No carrier gas passes through this trap. [0047] The seventh sequence of the sampling/analysis cycle (Sequence 7), is similar to Sequence 3 (i.e. valve positions, processes, etc.). Hence, Sequence 7 is a repetition of Sequence 3 and the subsequent sequences start repeating themselves (i.e. Sequence 8 = Sequence 4, Sequence 9 = Sequence 5, Sequence 10 = Sequence 6, Sequence 1 1 = Sequence 1 ...).

[0048] Embodiments of the invention utilize microwave heating to achieve pyrolysis as opposed to conventional heating. Compared to the conventional pyrolizing systems, embodiments of the invention have the following technical advantages.

[0049] Firstly, there is direct conversion of energy to heat and localized heating at the m icrowave absorbing material only. This leads to a low skin temperature (almost similar to ambient temperature) of the equipment as compared to conventional ovens which reach 800°C to 1000°C. For hazardous area classified equipment, the skin temperature determines the purged gas required to cool down equipment.

[0050] Secondly, concurrent heat and mass flow leads to uniform internal heating. This also leads to flash pyrolysis that cracks the hydrocarbon without the char/soot/particulate formations that leads to erroneous Hg detection.

[0051 ] Thirdly, there is rapid superheating of sample far above its boiling point in an operationally simple and safe manner. [0052] Fourthly, with the use of a specified catalyst which absorbs microwaves, the system is capable of cracking the hydrocarbon and breaking the Hg species into elemental form without recombination back to different species, allowing rapid analysis of Hg (less than 5 minutes cycle) versus conventional analysis cycle of 1 5 - 20 minutes for a complex hydrocarbon matrix.

[0053] It will be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the embodiments without departing from the scope of the invention as broadly described. The embodiments are, therefore, to be considered in all respects to be illustrative and not restrictive.

Claims

1 . A system for measuring mercury in a hydrocarbon stream, comprising:

a wave generator configured to emit microwaves;

a receptacle configured to hold a catalyst;

a fluid transporter configured to allow the hydrocarbon stream to be in fluid communication with the receptacle that is holding the catalyst; and

a waveguide disposed between the wave generator and the receptacle, the waveguide configured to channel the emitted microwaves to the catalyst such that the catalyst absorbs the microwaves to generate heat for converting mercury in the hydrocarbon stream into elemental mercury.

2. The system as claimed in claim 1 , wherein the catalyst absorbs the microwaves to generate heat to at least partially crack complex hydrocarbon molecules in the hydrocarbon stream into simpler hydrocarbon molecules.

3. The system as claimed in claim 2, wherein the receptacle is configured to hold an additional catalyst that is configured to adsorb at least the simpler hydrocarbon molecules.

4. The system as claimed in claim 3, wherein the receptacle comprises a separator to physically separate the catalyst and the additional catalyst when they are being held in the receptacle.

5. The system as claimed in any one of the preceding claims, further comprising a housing for enclosing the receptacle, wherein the housing comprises walls that are configured to reflect a portion of the emitted microwaves such that standing waves are formed in the receptacle at a resonant frequency to facilitate the generation of heat by the catalyst held in the receptacle.

6. The system as claimed in any one of the preceding claims, wherein the receptacle comprises quartz.

7. The system as claimed in any one of the preceding claims, wherein the catalyst comprises a substance having a dissipation factor of at least 0.30.

8. The system as claimed in any one of the preceding claims, wherein the catalyst comprises silicon carbide (SiC) and carbon (C).

9. The system as claimed in claim 8, wherein the catalyst has a SiC:C ratio ranging from 1 :0 to 1 :1 .

10. The system as claimed in claim 8 or 9, wherein the SiC comprises a-SiC or β- SiC.

1 1 . The system as claimed in claim 3 or 4, wherein the additional catalyst comprises a substance derived from a polymer-based material.

12. The system as claimed in claim 1 1 , wherein the polymer-based material is 2, 6-diphenylene-oxide.

13. The system as claimed in any one of the preceding claims, further comprising:

at least two mercury traps disposed downstream relative to the receptacle, in which at least one trap operates in an adsorption mode for adsorbing the elemental mercury while at least one other trap operates in a desorption mode for releasing the elemental mercury; and

a detector in fluid communication with the trap that is operating in the desorption mode for detecting mercury being desorbed therefrom,

wherein the at least two mercury traps are configured to alternate between the adsorption mode and the desorption mode to enable measurement of mercury in the hydrocarbon stream.

14. A method for measuring mercury in a hydrocarbon stream, comprising:

emitting microwaves from a wave generator;

providing a receptacle that is configured to hold a catalyst;

passing the hydrocarbon stream to the receptacle such that the hydrocarbon stream is in fluid communication with the receptacle that is holding the catalyst; and using a waveguide that is disposed between the wave generator and the receptacle to channel the emitted microwaves to the catalyst such that the catalyst absorbs the microwaves to generate heat for converting mercury in the hydrocarbon stream into elemental mercury.

15. The method as claimed in claim 14, wherein the catalyst absorbs the microwaves to generate heat to at least partially crack complex hydrocarbon molecules in the hydrocarbon stream into simpler hydrocarbon molecules.

16. The method as claimed in claim 15, wherein the receptacle is configured to hold an additional catalyst that is configured to adsorb at least the simpler hydrocarbon molecules.

17. The method as claimed in claim 16, further comprising physically separating the catalyst and the additional catalyst in the receptacle.

18. The method as claimed in any one of claims 14 to 17, further comprising positioning the receptacle within a housing that comprises walls that are configured to reflect a portion of the emitted microwaves such that standing waves are formed in the receptacle at a resonant frequency to facilitate the generation of heat by the catalyst held in the receptacle.

19. The method as claimed in any one of claims 14 to 18, wherein the catalyst comprises a substance having a dissipation factor of at least 0.30.

20. The method as claimed in any one of claims 14 to 19, wherein the catalyst comprises silicon carbide (SiC) and carbon (C).

21 . The method as claimed in claim 20, wherein the catalyst has a SiC:C ratio ranging from 1 :0 to 1 :1 .

22. The method as claimed in claim 20 or 21 , wherein the SiC comprises a-SiC or β-SiC.

23. The method as claimed in claim 16 or 17, wherein the additional catalyst comprises a substance derived from a polymer-based material.

24. The method as claimed in claim 23, wherein the polymer-based material is 2, 6-diphenylene-oxide.

25. The method as claimed in any one of claims 14 to 24, further comprising: providing at least two mercury traps disposed downstream relative to the receptacle, in which at least one trap operates in an adsorption mode for adsorbing the elemental mercury while at least one other trap operates in a desorption mode for releasing the elemental mercury;

providing a detector in fluid communication with the trap that is operating in the desorption mode for detecting mercury being desorbed therefrom, and

configuring the at least two mercury traps to alternate between the adsorption mode and the desorption mode to enable measurement of mercury in the hydrocarbon stream.