Sample dispersing apparatus and method

An apparatus and method for dispersing a sample in a process stream is disclosed. The apparatus comprises a conduit which receives a sample at a first end and passes the sample to a pyrolysis furnace through a second end. A port is provided to admit a carrier gas. A dispersing device, preferably consisting of quartz wool, distributes the sample throughout the conduit, so that the sample may be heated by the pyrolysis furnace without coking. The method comprises the steps of receiving a sample in a conduit, dispersing the sample within a fluid carrier such that the sample is uniformly mixed throughout the fluid carrier.

FIELD OF THE INVENTION 
The field of the invention relates generally to an apparatus and method for 
detecting the concentration of a fluid. Specifically, the present 
invention relates to an apparatus and method for dispersing a sample 
containing sulfur, nitrogen and other fluid compounds prior to engaging 
the sample with a pyrolysis furnace. 
BACKGROUND OF THE INVENTION 
Chemical plants, oil refineries and other industrial facilities produce 
fluids which present health and safety problems. In some situations, even 
small amounts of the fluid, for example, a few parts per million or even a 
few parts per billion, can constitute serious health, safety and 
environmental problems. Also, such fluids and gases can be a danger to 
workmen in the vicinity of the facility. The difficulties in detecting and 
determining the presence of a selected fluid in a process stream or in the 
environment is exceedingly difficult due to the extensive nature and the 
large size of industrial plants. 
Thus, the detection and monitoring of fluids associated with industrial 
plants is highly advantageous with respect to health, safety and 
environmental concerns. Further, the detection and monitoring of 
industrial fluids can prevent other dangers such as ignition, plant 
failure and the like. 
Further, the need to detect particular constituents in a process stream can 
be based on product quality, process control, regulatory requirements and 
financial considerations. Particular fluid constituents of interest are, 
for example, hydrogen sulfide and nitrogen oxides. Industrial monitoring 
equipment exists for all phases of industry. Particularly, a variety of 
equipment is available using colorimetric methods. Colorimetric monitoring 
is utilized in process streams and associated atmospheres in and about 
industrial facilities. The colorimetric equipment and methods that are 
prevalent include absolute darkness techniques, tape difference techniques 
and analog first derivative techniques. Typically using colorimetric 
equipment, an ambient atmosphere is passed through the apparatus whereby 
the fluids in question react with a color-altering material. The magnitude 
of the color change is proportional to the concentration of the fluid in 
the atmosphere. 
All colorimetric methods have problems. For example, some samples not 
adequately dispersed cause coking on the side of the conduit when passing 
through a pyrolysis furnace. Also, absolute darkness techniques are 
subject to noise from zero fluctuation. The noise from zero fluctuations 
is due to the non-uniform reflectance characteristics of the colorimetric 
sensing media. Similarly, tape difference techniques require a zero 
reading. After the zero reading, a period of time must elapse between the 
initial reading and the final reading. The relatively long time period 
between readings does not take into account the nonlinearity of the 
sensing media and effects the response time of tape difference techniques. 
Analog first derivative techniques are subject to power line 
interferences. Further, analog first derivative techniques are limited by 
the current leakage in the differentiating capacitor which is typically 
used. Still further, the analog first derivative techniques operate in the 
linear portion of the response of the sensing device and require a linear 
response curve relationship for accurate results. 
Many colorimetric analyzers generally have light sources, optics and 
detectors fixed in a rigid framework with light paths of the optics 
traversing through the ambient air. Such colorimetric analyzers require 
that correct alignment of the optical components be maintained during the 
operation of the equipment. The alignment of the optics is typically 
subject to environmental factors as well as mechanical problems. Examples 
of environmental and mechanical problems include changes in temperature, 
operation of equipment in high vibration environments, mechanical stress 
associated with typical equipment use, and the like. 
Of additional concern is the environment in which the apparatus must 
operate. It is not unusual that the apparatus is required to be explosion 
proof for operation in industrial facilities. Typically, an explosion 
proof apparatus must be housed in a purged cabinet or housed in an 
explosion proof enclosure. The use of explosion proof equipment creates 
many problems with respect to adjustment, maintenance and calibration of 
the apparatus without compromising the protective environment of the 
explosion proof equipment. 
It is, therefore, a feature of the present invention to provide a sample 
dispersing apparatus and method for use in combination with a pyrolysis 
furnace for diffusing the specimen prior to introducing the specimen into 
the pyrolysis furnace. 
A feature of the present invention is to provide a sample dispersing 
apparatus and method for use in combination with a pyrolysis furnace whose 
scattering parameters can be changed or modified depending on the 
requirements of the particular analysis. 
Another feature of the present invention is to provide a sample dispersing 
apparatus and method for use in combination with a pyrolysis furnace that 
provides enhanced sensitivity. 
Still another feature of the present invention is utilizing a ceramic means 
for dispersing a sample immediately prior to entering a pyrolysis furnace. 
Additional features and advantages of the invention will be set forth in 
part in the description which follows, and in part will become apparent 
from the description, or may be learned by practice of the invention. The 
features and advantages of the invention may be realized by means of the 
combinations and steps particularly pointed out in the appended claims. 
SUMMARY OF THE INVENTION 
To achieve the foregoing objects, features and advantages, and in 
accordance with the purpose of the invention as embodied and broadly 
described herein, an apparatus and method for dispersing a sample for use 
in combination with a pyrolysis furnace for measuring the concentration of 
a fluid in a process stream or environment is disclosed. 
The apparatus for dispersing a sample for use in combination with a 
pyrolysis furnace for measuring the concentration of a fluid in a process 
stream or environment comprises a conduit having a first end for receiving 
the sample and a second end through which the sample passes from the 
conduit. The pyrolysis furnace is associated with the second end of the 
conduit for heating the conduit and any sample passing through the 
conduit. A dispersing device distributes the sample throughout the conduit 
such that the sample is heated in the conduit by the pyrolysis furnace 
without causing coking within the conduit. Preferably, the dispersing 
device strews the sample. The sample can be strewn by increasing the 
surface area of the sample, for example, on the dispersing device. An 
example of a dispersing device is quartz wool. Other examples of 
dispersing devices may be readily available or known to those skilled in 
the art. 
The method for dispersing a sample for use in combination with a pyrolysis 
furnace for measuring the concentration of a fluid in a process stream or 
environment comprises the steps of (a) receiving a sample into a first end 
of a conduit having a channel there through, (b) dispersing the sample 
throughout the cross section of said conduit, (c) engaging the disbursed 
sample in the channel of the conduit with the pyrolysis furnace for 
initiating the pyrolization. Preferably, the dispersing step increases the 
surface area of the sample. Alternately, the dispersing step strews the 
sample essentially throughout the cross section of the channel. The strewn 
sample may be uniform across the diameter of the channel, e.g., linear, or 
may be uniform about the center or radius of the channel, e.g., Gaussian. 
The method of the present invention comprises the steps of receiving a 
sample in a conduit, intercepting the sample for dispersing, 
disseminating, evaporating or strewing the sample uniformly throughout the 
conduit, and engaging the uniform sample with a pyrolizer. The step of 
intercepting the sample further comprises engaging the sample with a 
material porous enough or loose enough to provide the sample to flow there 
through in a uniform manner, and disengaging the sample from the material. 
More particularly, the step of engaging the sample with a material 
comprises the step of dispersing the sample over the surface area of the 
material. 
Similarly, the step of intercepting the sample further comprises injecting 
the sample to be uniform across the reach or diameter of the conduit. Yet 
still more particularly, the step of interjecting the sample provides that 
the sample is essentially linear across the reach or diameter of the 
conduit. 
In yet another embodiment, the step of intercepting the sample further 
comprises the step of interjecting the sample to be uniform about the 
center or radius of the conduit. More particularly, the step of 
interjecting the sample comprises that the sample is essentially Gaussian 
about the center or radius of the conduit. 
Generally, the dispersing device and method of the present invention uses 
material that is porous or loose enough to provide that the sample flows 
uniformly through the material. The dispersion is initiated by the 
interception of the sample such that the sample is uniformly dispersed, 
distributed, evaporated or strewn throughout the conduit. It can be 
appreciated that many materials or devices may meet this criteria. For 
example, quartz wool is a preferred dispersant.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Reference will now be made in detail to the present preferred embodiments 
of the invention as described in the accompanying drawings. 
FIG. 1 illustrates a dispensing apparatus 100. The dispensing apparatus 100 
comprises a conduit 101 having an input aperture 102 and an exit aperture 
104. The conduit 101 has, between the input aperture 102 and the exit 
aperture 104, a channel 106 there through. Engaged within the channel 106 
of the conduit 101 is a diffuser 110. The conduit 101 is attached to a tee 
150 at the input aperture 102, and is attached to a pyrolysis furnace 160 
at the exit aperture 104. The tee 150 has a sample input port 130 and a 
carrier input port 140. 
The sample enters the sample input port 130 passing through the tee 150. 
Concurrently, if appropriate, a carrier gas enters the carrier input port 
140 passing through to the tee 150. The sample engages the diffuser 110 
immediately prior to entering the pyrolysis furnace 160. The diffuser 110 
provides that the sample is dispersed within the cross sectional area 
associated with the channel 106 of the conduit 101. Thus, the sample can 
pass through the channel 106 toward the exit aperture 102 within the 
pyrolysis furnace 160 without creating deposits on the channel 106 due to 
the heating of the sample by the pyrolysis furnace 160. 
It has been found that glass or quartz wool proves to be an adequate 
diffuser 110 for use in the dispensing apparatus 100. The sample input 
port 130 can be adapted for accepting a needle from a syringe. Using the 
diffuser 110 within the channel 106 associated with the pyrolysis furnace 
160 provides that the carrier gas picks up all the liquids and/or sulfur 
for mixing and for transferring them into the high temperature zone of the 
pyrolysis furnace 160. 
One purpose of the wool diffuser 110 is to prevent liquid hydrocarbon from 
entering the pyrolysis furnace 160. The sample, e.g., liquid hydrocarbon, 
is vaporized and mixed with the carrier gas stream prior to entering the 
pyrolysis furnace 160, preferably by physically retaining the liquid in 
the hydrogen effluent stream via the wool diffuser 110. 
FIG. 2 is a flow a diagram illustrating the method of the present 
invention. First, FIG. 2 illustrates that a sample is received in a 
conduit. The sample received in the conduit is intercepted. Intercepting 
the sample encompasses dispersing, evaporating, strewing or some other 
description which describes the dissemination of the sample in the 
conduit. Lastly, the sample which was intercepted is engaged with a 
pyrolysis furnace. 
FIG. 3 illustrates additional steps which can be associated with another 
embodiment of the present invention as shown in FIG. 2. Particularly, FIG. 
3 illustrates two different ways of intercepting the sample. First, the 
sample can be intercepted by engaging the sample with a porous enough or 
loose enough material such that the sample flows through the material in a 
uniform manner. After the sample flows through the material, the sample 
disengages from the material for dispersing, evaporating or strewing the 
sample in the conduit. 
Yet still another embodiment of the present invention includes a three-step 
method of intercepting the sample. The interception of the sample may 
include engaging the sample with a porous enough or loose enough material 
for the sample to flow through the material in a uniform manner. 
Thereafter, the sample is dispersed over the surface area of the porous 
material. Lastly, the dispersed sample is disengaged with the material in 
the conduit. 
Any dispersing material or device which meets the specific criteria of the 
present invention is readily adaptable for use. The material must be 
porous enough or loose enough to provide that the sample flow through the 
material is uniform. The sample is intercepted or redirected by the 
material. Also, the intercepted sample may be dispersed over the surface 
area of the material. Still further, the sample may be dispersed by the 
material, strewed by the material, or result in enhanced evaporation by 
the material. It can be appreciated by those skilled in the art that 
various and differing materials can be used for achieving the present 
invention. Also, it can be appreciated by those skilled in the art that 
various and sundry different devices can be used having the 
characteristics required for practicing the present invention.