Laboratory scale incinerator simulation system

A laboratory scale incinerator simulation system having a primary combustion furnace and an associated secondary combustion furnace with both such combustion furnaces being adapted so that they can function with combustion chambers of various volumes to permit study of a wide variety of combustion parameters for determining optimum incineration conditions in commercial incinerators for both liquid and solid materials.

BACKGROUND OF THE INVENTION 
The present invention relates to a laboratory scale incinerator simulation 
system enabling a variety of liquid and solid materials to be combusted 
under various process conditions in order to predict incineration 
conditions in large commercial incinerators and optimum incinerating 
conditions therefor based on measurements of combustion byproducts and 
exit gases. 
At the present time there has been increased effort to incinerate wastes in 
an environmentally acceptable and economic manner. This ideally requires 
using the optimum conditions to incinerate and, hence, optimization of 
incinerating conditions for a wide variety of different liquid and solid 
waste materials, such as rate of waste introduction into the incinerator, 
primary incinerating conditions, secondary treatment conditions, and the 
like, and their interrelationship. Also, there is no accurate system to 
predict emissions from the combustion of new waste products or waste 
streams to determine optimum conditions for incineration thereof, or 
whether, in fact, incineration is a viable method for disposing of the 
same. 
At the present time, other than actual studies in large scale commercial 
incineration equipment in which it is difficult to vary the incineration 
parameters and to study the incineration byproducts because of the size of 
the equipment and the large volumes of byproducts, there is no 
satisfactory small scale system permitting accurate studies to be 
conducted under careful controlled conditions. 
There is no economic, rapid, and accurate system enabling one to vary all 
the parameters of an incinerator in order to determine optimum 
incinerating conditions in large commercial scale incinerators for any 
given waste, liquid or solid. Moreover, the available pilot or laboratory 
scale equipment utilized generally is suitable only for batch or for 
continuous operation and it is not heretofore been possible to operate the 
same incinerator simulator system in both modes. Also, some systems are 
not capable of modeling both the primary and secondary combustion 
processes under different combustion conditions. Some current systems for 
incinerator simulation also do not have a separate air controls for 
primary and secondary combustions zones thus not permitting accurate 
control over these important combustion variables. As a consequence, large 
amounts of particulates produced during the combustion have introduced 
analytical' differences in prior systems. Such carbonaceous particulates 
have been implicated in dioxin formation as they may provide a catalytic 
surface and/or organic material for dioxin formation. 
Further, many of the current systems have but one size combustion zone and 
as a consequence it is not possible to provide more accurate control for 
various combustibles with respect to the gas residence times in the 
combustion zone or to vary the size sample to be treated in such zone. 
SUMMARY OF THE INVENTION 
The present invention overcomes the problems of the existing systems and 
provides a laboratory scale incinerator for accurately simulating 
incineration of liquid and solid waste materials in large, commercial size 
incinerators permitting laboratory study of wastes by accurate 
manipulation of fundamental incineration parameters including, but not 
limited to, waste feed rate, temperature in multiple heating zones, 
independent air supplies for the primary and secondary combustion zones, 
and gas phase residence time in the secondary zone. 
Briefly stated, the present invention comprises a laboratory scale 
incinerator simulation system comprising, in combination: 
(a) a primary combustion means having a primary combustion zone in the 
interior thereof with a primary combustion chamber extending therethrough, 
(b) a secondary combustion means having a secondary combustion zone in the 
interior thereof with a secondary combustion chamber extending 
therethrough, said secondary combustion chamber being in fluid-flow 
communication with said primary combustion chamber, 
(c) means operatively associated with said primary combustion means to 
introduce a specimen into said primary combustion chamber for 
incineration, 
(d) control means associated with each of said primary and secondary 
combustion chambers to vary the combustion conditions in each, and 
(e) sampling means associated with each of said primary and secondary 
combustion chambers for monitoring combustion conditions therein and 
resultant combustion byproducts; 
(f) each of said primary and secondary combustion zones being adapted to 
receive and function with combustion chambers of different volumes.

DETAILED DESCRIPTION 
Referring to the drawings, it will be seen that the system 10 comprises two 
combustion means, first or primary combustion furnace 11 and secondary 
combustion furnace 21. Each of the furnaces 11 and 21, comprises an outer 
metal (preferably steel) shell 12 and 22, with conventional (preferably 
ceramic)insulation 15 and 25 between the respective shells defining 
primary and secondary combustion zones 14 and 24, respectively. 
Conventional electrical heating elements 13 and 23 are located with 
insulation 15 and 16 and act to heat combustion zones 14 and 24, 
respectively. Passing through combustion zones 14 and 24 are combustion 
chambers 16 and 26. Chambers 16 and 26 are preferably tubes made of a 
heat-resistant material, such as quartz or a ceramic, and extend beyond 
the respective outer shells 12 and 22. Each of combustion chambers 16 and 
26 is removably attached to the respective furnace shells 12 and 22 by 
conventional removable tubing adapters 30 and 31 which also act to suspend 
chambers 16 and 26 so that they are evenly heated. The size of the 
combustion zones 14 and 24 is such that tubes 16 and 26 of varying 
diameters can be placed therein with suitably sized tube adapters 30 and 
31 to permit control of sample capacity and combustion gas residence 
times. 
Primary combustion chamber 16 is coupled to the secondary combustion 
chamber 26 furnace 21 by means of ceramic connector 32 to permit fluid 
flow communication of all combustion materials from the chamber 16 passes 
into chamber 26. Connector 32 is preferably heated by conventional 
electrical heating means wrapped thereabout (not shown) to maintain the 
temperature of the initial combustion products as they pass from chamber 
16 to chamber 26. 
Sample introduction tube 33 is sealingly connected to entrance 17 of 
combustion chamber 16 and has a sample introduction opening 34 provided 
with removable stopper 35 having primary combustion gas introduction means 
36, a hollow rod, passing therethrough. Combustion gas is passed through 
rod 36 and tube 33 and into combustion chamber 16 from a conventional 
combustion gas metering device 37. 
The liquid or solid to be combusted is placed in sample holding means 38, a 
quartz or ceramic boat, and the boat 38 placed in tube 33 and then into 
combustion chamber 16. It will be evident that stopper 35 is removed to 
position boat 38 in tube 33 and stopper 35 then repositioned in tube 33. 
Wire 39 or other suitable tow device is associated with a take-up reel on 
motor 40 and attached to sample boat 38 so that sample boat 38 can be 
pulled at any desired regulated rate into and through primary combustion 
chamber 16 and into capture tube 41, tube 41 preferably being also made of 
quartz or a ceramic and being suitable sealed at its discharge end 42, 
with only a sealing opening for movement of wire 39 therethrough. In order 
to prevent escape of any of the combustion products from chamber 16, 
noncombustible movable blanket plug 42 is placed at the end of tube 41 
through which wire 39 can pass in a sealing relationship without 
permitting escape of any of the combustion gases or solids therethrough. 
The length of sample boat 37 and its rate of passage through combustion 
zone 14, is such that the specimen being combusted is completely degraded 
prior to the time the front of sample boat 38 contacts plug 42. Moreover, 
as sample boat 38 is further moved it simply moves plug 42 in front of it 
while the remainder of capture tube 41 remains sealed. Alternatively, 
sample boat 38 can also be pushed through chamber 16 by conventional 
pushing means. 
After any given combustion test is completed one can simply remove capture 
tube 41 from connector 32 to remove sample boat 38. 
Provided adjacent exit 18 of chamber 16 are test ports 19 and 20 in which 
samples of the products of combustion, such as gases, semi-volatiles, and 
the like can be extracted for studies as well as temperature monitoring of 
the exhaust by means of a thermocouple or the like. It is evident that 
though two ports 19 and 20 are shown, a single port or greater number of 
ports can be used. 
Combustion zone 14 is divided into three temperature control areas A, B, 
and C for the primary combustion, it being understood that a lesser or 
greater number of such can be utilized. A standard controller and power 
supply unit 44 is connected in the conventional manner to the furnace 11 
for controlling the temperature in chamber 16 for each of areas A, B, and 
C. Initial area A can be a preheat zone where temperatures of up to 
500.degree. C. or higher can be provided and the primary combustion is 
carried out in areas B and C wherein the temperature can regulated in each 
up to 1,000.degree. C. or higher as is desired for any test. Conventional 
controllers that can be used include PID types such as EUROTHERM or others 
such as BARBER-COLMAN devices and all can be utilized to closely regulate 
the temperatures in each of the zones of the furnace 11 as well as furnace 
21 which also has a like controller 74 to regulate the temperature. 
Furnace 21 contains auxiliary combustion gas input port 46 for introducing 
gas for secondary combustion to secondary combustion chamber 26 from 
metering device 47. 
The system 10 can be operated in a horizontal or vertical position to 
enable experimentation to duplicate the positioning of the commercial 
incinerator being studied. 
At the exhaust end 48 the secondary combustion chamber 26 there is shown 
test port 49 for sampling the temperature, gases, and the like. Additional 
ports can be used. 
FIG. 2 discloses incorporation with system 10 of an effluent processing 
unit 50 for intensive study of the materials leaving secondary combustion 
chamber 26 which is sealingly attached to exhaust 48 by means of a 
noncombustible blanket material 51. Unit 50 comprises a T-shaped coupler 
52 connected at one end to exhaust 48 and at another end to a jacketed 
condensor 53 through which the exhaust pass into jacketed sampling module 
54. Jacketed module 54 consists of filter means 55 for capturing 
semi-volatile materials, most suitably a polyurethane foam filter or other 
conventional trapping material. Module 54 is attached to condensor 53 by 
means of a conventional connector 57. In turn, sample module 54 is 
connected by conventional tubing to cleaner module 56 for capturing solids 
and acidic materials, and is preferably a cylinder containing charcoal or 
other absorbent material. 
The exhaust fluids are pumped through the unit 50 by means of pump 58 and 
passed into dry gas meter 59 to measure the volume of the fluid before it 
is exhausted from the system. Provided in unit 50 are temperature 
measuring devices, such as thermocouples 60 and 61, located so as to 
enable measurement of the exhaust fluid temperature at the exhaust end 48 
of chamber 26 as well as at condensor 53. A sample port 62 is also used in 
the condensor in order to be able to remove specimens therefrom and 
analyze the same. 
It will be evident that only gas will leave the unit 50 through exit 63 and 
depending upon the nature of the combustion products; if it is completely 
harmless at that point it can be vented to the atmosphere and if not 
harmless, it can be placed into a suitable holding container. 
Water lines 64 are connected to chilling bath 65 so as to circulate cold 
water through jacket 66 of condensor 53 and sampling module 54 to cool the 
fluid and condense any volatilized material therein prior to its passage 
through filter trapping means 55. 
After a test run has been completed, unit 50 can be disassembled to remove 
filter 55 and cleanup module 56 so the material collected therein can be 
studied. 
The operation of the system is largely evident from the description given, 
but typically the temperature that can be set in preheat area A ranges 
from 100.degree. C. to 300.degree. C. or higher, combustion area B can be 
set to a temperature of 550.degree. C. to 1000.degree. C., or higher and 
combustion area C can be set at temperatures of 550.degree. C. to 
1000.degree. C. and higher. The secondary combustion chamber can be 
maintained at temperatures of 900.degree. C. to 1200.degree. C. The 
controllers noted for each furnace 11 and 21 are, as indicated, 
conventional devices which are microprocessor based with a solid state 
power module with each area or zone independently controlled. Combustion 
zones 14 and 24 are sized so as to enable insertion therethrough of 
combustion chambers 16 and 26 of different diameters; i.e., ranging from 
25 to 150 millimeters in diameter. 
Sample boat 38 is pulled through the furnace 11 and through the areas A, B, 
and C at any desired rate. The feed rate can be computer controlled by 
controlling motor 40 and can be fixed or variable during any given test 
run. 
System flows are controlled by commercial high accuracy calibrated 
rotameters 37 and 47, or digital mass flow controllers. The system is 
capable of functioning at control levels or 0-350% or greater theoretical 
air to fuel ratio, and typically the ranges for both the primary and 
secondary combustion chambers 16 and 26 are 50% to 150% theoretical air. 
As noted, system 10 is equipped with a minimum of two supply air ports, 
the first for the primary combustion chamber 16 and the second for the 
secondary combustion chamber 26. The input air can be mixed via the 
rotameter described above and manifold system so that varying mixtures of 
nitrogen, oxygen or other gases can be supplied to the combustion zones. 
The number of test ports, are noted, can be varied and as is conventional 
these can be monitored and controlled using conventional computer based 
data acquisition software which allows for maximum flexibility and data 
acquisition and system control. LABWINDOWS, an available software program, 
for example, can be utilized for the monitoring. Such system hardware 
consists of 486 based PC for data storage and analysis. Thus, it is 
possible to gather data which includes all operating parameters, such as 
set temperature and control settings, actual temperature histories, feed 
rate, gas sampling, and the like. 
The instant system provides a highly accurate and versatile means for being 
able to determine in the laboratory or pilot plant the optimum 
incineration conditions for a wide variety of liquid and solid materials 
for any large scale commercial incinerator. 
While the invention has been described in connection with a preferred 
embodiment, it is not intended to limit the scope of the invention to the 
particular form set forth, but on the contrary, it is intended to cover 
such alternatives, modifications, and equivalents as may be included 
within the spirit and scope of the invention as defined by the appended 
claims.