Combustion Characteristics of the GE LM2500 Combustor With Hydrogen-Carbon Monoxide-Based Low Btu Fuels

Transcription

1 THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS 345 E. 47 St., New York, N.Y GT-179 The Society shall not be responsible for statements or opinions advanced in papers or in ti S^.7 discussion at meetings of the Society or of its Divisions or Sections, or printed in its publications. Discussion is printed only if the paper is published in an ASME Journal. ^L Released for general publication upon presentation: Full credit should be given to ASME; the Technical Division, and the author(s). Papers are available from ASME for nine months after the meeting. Printed in USA. Copyright 1985 by ASME Combustion Characteristics of the GE LM2500 Combustor With Hydrogen-Carbon Monoxide-Based Low Btu Fuels P. E. SABLA and G. G. KUTZKO Aircraft Engine Business Group General Electric Company Cincinnati, Ohio ABSTRACT An experimental test program was conducted with the objective of evaluating the combustion performance of fuel gases comprised of mixtures of carbon monoxide, hydrogen, and nitrogen. These gases were intended to be representative of alternate fuels that might be produced by air blown coal or biomass gasifiers. The purpose of this test program was to identify if the LM2500 combustion system would burn fuels at heating values (150 Btu/SCF -250 Btu/SCF) typical of those produced by gasifier processes. Two combustor configurations were tested and two representative gas compositions were evaluated. The objectives of this test were to determine the flammability or burning limits for the two combustor designs and the impact of the low heating value gas on combustor exit temperature performance. Both designs exhibited burning limits substantially below the target caloric level. The exit temperature measurement showed the exit temperature distribution quality was adversely affected due to the high volumetric gas flows. However, this exit temperature distribution degradation is not severe enough to make the burning of a low heating value fuel prohibitive in the LM2500 engine. NfMFNC.I ATIIRF Symbol Definition A Standard LM2500 Gas Fuel Nozzle Area A4 LM2500 Low Btu Fuel Nozzle Area f Fuel-Air Ratio LHV Lower Heating Value, Btu/SCF P3 Compressor Discharge Total Pressure, atm PF Pattern Factor 1 3Compressor Discharge Total Temperature or Combustor Inlet Temperature T avg,t4 Combustor Exit Average Tmax W a ATavg W f hpr Q INTRODUCTION Temperature Combustor Exit Maximum Temperature Combustor Airflow Rate, lb/sec Tavg-T3 Combustor Fuel Flow Rate - pph Horsepower Volumetric Flow - ft 3 /sec There is increased interest in alternative fuels derived from nonpetroleum based resources. In particular, the use of coal or biomass materials to produce a combustible fuel for use in industrial gas turbines appears to be a very economical energy source. The gasifier requires large quantities of air to extract the combustibles and since the gasification is a chemical process in itself, the resulting gas supply contains large quantities of inerts such as carbon dioxide (CO2) and nitrogen (N2). These large quantities of inerts in combination with the combustibles produce a gas with low Btu content. The large air supply capacity of the General Electric LM25UO gas generator and the demonstrated excellent performance of the LM2500 combustion system provided impetus to investigate the capability of the LM2500 combustor to burn low heat content fuels. Presented at the Gas Turbine Conference and Exhibit Houston, Texas March 18-21, 1985

2 The LM2500 engine has previously demonstrated the capability to operate on hydrocarbon based gaseous fuels down to about 300 Btu/SCF (11.2 MJ/M 3 ) with nitrogen and carbon dioxide as the major diluents. However, no data is available on the LM2500 combustion system when operating on other gaseous combustibles. Therefore, the purpose of this test program was to identify if the LM250U combustion system would burn fuels at caloric heating values (150 Btu/SCF Btu/SCF) ( MJ/M 3 )typical of that produced by a gasifier process. The gasifier supplies a fuel containing hydrogen, carbon monoxide, and hydrocarbons as the combustibles and nitrogen and carbon dioxide as inerts to the engine. BACKGROUND The General Electric LM2500 marine and industrial gas turbine is a derivative of the TF-39/CF6-6 family of engines used extensively in military and commercial aircraft service. Therefore, the CF6-6, and subsequently the LM2500, has accrued a significant amount of operating experience. The CF6-6 and marine versions of the LM2500 both operate primarily on liquid fuels, such as kerosene and have demonstrated excellent reliability. The LM2500 in industrial service has accrued over one million hours of trouble free operation on conventional fuels such as natural gas. However, as concern over diminished petroleum supplies in the USA and higher costs for natural gas and petroleum derived fuels increases, there is renewed interest in the use of alternate gaseous fuels for application in advanced marine and industrial engines such as the LM2500. For example, the real retail price of natural gas has more than doubled between 1973 and It is also important that gas turbine engines have the capability and flexibility of being adapted to locally available fuels. The initial fuels considered of extreme interest to present and future users of the LM2500 were those obtained as byproducts of industrial process or gas conditioning plants, which are generally high in inerts such as carbon dioxide (CO2) and/or nitrogen (N2), and low in hydrocarbon combustibles such as methane, ethane, and propane. Because of process differences, it is necessary to design a combustor that will tolerate heating value variations due to changes in combustible to inert composition ratios and still provide acceptable operation over the entire operating range of the engine. An engineering program was initiated in January, 1980 to determine the capability of the LM2500 engine to operate with hydrocarbon based reduced heating value fuels. The overall objective of this program was to evaluate the current operational capability of LM25UO engines to perform satisfactorily on medium Btu ( Btu/SCF) ( MJ/M 3 ) gaseous fuels. The specific objective was to determine the minimum practical gas heating value which can be used in an unmodified LM2500 gas turbine combustor and to quantify the effects of fuel chemistry variations on the minimum heating value. The prime emphasis was directed to medium Btu gaseous fuels derived from petroleum sources with CO2 as the diluent. An extensive component test program was conducted at atmospheric and high pressure conditions using natural gas and propane diluted with CO2, N2, or steam. The component test program was followed by a LM2500 demonstrator engine (gas generator) test conducted with natural gas diluted with steam since it was a readily available diluent (1). Based on this extensive component and engine test program, it was concluded that the current LM2500 engine will operate, satisfactorily on 300 Btu/SCF (11.2 MJ/M 3 ) gas fuels consisting of hydrocarbons heavily diluted with CO2 and on natural gas and/or liquid fuel. The current production LM2500 operational map could be extended down to 25U Btu/SCF (9.3 MJ/M 3 ) on low Btu gas fuels consisting of more favorable diluents like N2 and/or steam. The only change required to the basic combustion system is in the fuel nozzle, whose tip flow area and pressure ratio must be sized based on the heating value of the gas to be used. Since the conclusion of this program, vigorous activity has continued in the direction of identifying alternative fuel sources exclusive of petroleum derived fuels. Major interest has been in the direction of generating energy from coal or nonfossi1 type fuels via gasification processes. These gases typically have a heating value in the 100 (3.72 MJ/M3 ) to 250 (9.3 MJ/M 3 ) Btu range, and contain chiefly hydrogen (H2), methane (CHO), and carbon monoxide (CO) as combustibles with large proportions of CO2 and N2. Because of the gas density/heating value characteristics of the constituent gases, large quantities of these low Btu gases are necessary to provide required engine neat rates. In order to handle the increased volumetric flows, it might be necessary to make certain engine changes. These changes could include a fuel nozzle change, a redesigned combustor with possible dome and primary zone area changes, inner flowpatn structural changes (due to combustor change) and necessary control system changes. The purpose of the program described herein was to determine the type and degree of such design changes. LM2500 TEST PROGRAM To investigate the performance of the LM2bUU combustion system with gaseous fuels typical of those produced in a coal gasifier, a full annular - full scale test program was formulated fashioned after the earlier successful LM2500 low Btu gas tests. Combustion System The LM2500 engine and its combustion system are shown in Figure 1. The combustor is a full annular design with film cooled liners and a multiswirler dome for atomizing and mixing the fuel and air in the combustor primary zone.

3 Venturi ^" 1^ _..-Imo '- yt r - r a Figure 1 - LM2500 Gas Generator lj- ^ --_.- ll n-+a-rte.a II Ideally, no changes to the standard combustion system would be desirable when operating on low Btu fuels. However, due to pressure limitations of the fuel supply, it was necessary to enlarge the discharge area of the natural gas fuel nozzles as shown in Figure 2 and increase the manifold and supply line diameters accordingly. Holes, 4 Places Nozzle Fuel Orifice ConfigurationEffective Area, In 2 ( c^m 2 ) Al Natural Gas A (.668) Low Btu Gas (4xAl) Figure 2 - LM2500 Gas Fuel Injectors The only change considered for the combustor itself was the possible removal of the swirl cup venturi, shown in Figure 3. Due to the very high volumetric gas flows being introduced into the primary zone, it was anticipated that removal of the venturi would promote more mixing of the gas and air prior to entering the combustion zone. Fuels Figure 3 - LM2500 Combustor Composition of the gas provided from a gasification process is expected to vary to some degree due to transient conditions and variables within the process. The range of these variations of gas composition expected are shown in Table 1. It would not be economically feasible to address such a wide range of compositions in this test program. Therefore, three gas compositions were selected which would evaluate a nominal value for the high heating value fuel, a more adverse gas composition (least hydrogen) for the lowest heating value fuel, and an intermediate value. A gas mixture containing a constant ratio of CO to H2 was used in conjunction with pure CH4 to represent the proposed gas mixtures. The typical gas mixtures shown in Table 1 contain quantities of ethylene (C2H4) and CO2. To simplify the test, sufficient methane to provide an equivalent heating value was substituted for the C2H4 and N2 was used in place of CO2. Although the substitution of CH4 is expected to have no bearing on the results, the substitution of N2 for CO2 could produce more conservative results. However, the impact would not be expected to adversely affect the results more than 5% based on results from (1). Therefore, it was decided that satisfactory test results could be obtained with a low Btu gas composed of a CO/H2 mixture, CH4 and N2 as a diluent. TABLE 1 - GASIFIER FUELS NOMINAL COMPOSITION TYPICAL GASIFIER FUELS TEST FUEL HEATING VALUE - BTU/SCF (MJ/M 3 ) ( ) ( ) GAS COMPOSITION - VOL. H CO CH C2H N CO2 l

4 i Test Apparatus The LM2500 low Btu tests were carried out in a full annular full scale component test rig. The test rig, shown in Figure 4, duplicates the flowpath of the engine and includes turbine bleed flows. Therefore, all of the velocities and flow distributions are very similar to the engine. Two ultraviolet flame detectors were installed through the combustor casing to provide a remote indication of flame in the combustor. This precautionary step was taken to avoid physically observing the combustion process and the associated dangers of carbon monoxide poisioning of test personnel if flame extinction should occur. Igniter Higft Pressure Gas Ste Air Heater T F(593K) Figure 4 - Longitudinal Section of LM2500 Annular Combustor -_- ^.- Cb t of nuo 3 L^ Figure 6 - Combustion E A, l Flow Source 0uIIE Up Area e^. P - 300o a(2 07MPa) ^ Tes t tc e11=._.i Test Facility W-zS PPSl11.36k 9-'s) The test was conducted in Cell AS in Evendale, Ohio. The test rig was installed in the test cell, as shown in Figure 5, with the LM2500 combustor discharging to atmosphere. The test rig was supplied with unvitiated air at temperatures up to 1000 F (538 C). The gas supply contained three independently controlled gas systems which fed into a static mixer prior to entering the combustor fuel supply manifold. Thus, a homogeneous mixture was supplied at all times to the test rig. The gas supply system is shown in Figures 6 and 7. Fuel (Meth Storage FuelRegulation - Fuel Metering. ae ane l 4 ( ) ^ Heat Exchan9e `l ^ Jk,-^1 T I I_^^,7 1 i ; I Fes' ^--^ ^ Ner^ - Carb {fn Monoxide' y1ydrogen 1 (rc9/}j2j _l N2 ^', L J- r^ (^ J _^Y 1 r F -1 -,. _ ^Mixe -.^.' 1 I--I i Lr. 4 LM2500(U-CH Gas Manifold Sri--iffy ^ ^ ^ Lr' -I F1- ^i- ^^ Fiure g 7 - LM2500 Low BTU Gas Supply System Test Approach FIGURE 5 Cell A-3 - Evendale Full Annular Combustor Test Facility, Interior View The combustor configuration was a standard design and utilized gas nozzles as shown previously in Figure 2. Tne Al size nozzles are used for pure methane or natural gas testing, while the A4 nozzles are used for low Btu gases. Two key performance parameters were considered in formulating the test program to evaluate the capability of the LM2500 combustor to operate with low Btu fuels produced by a gasifier process. The first was to determine the flammability limits of the combustor over the range of engine operating conditions of interest. The ability of the combustor to burn large quantities of gas with a low heating value (Btu/SCF) would be paramount for a viable engine system. The second was to determine the impact of low heating value gas fuels on combustor exit temperature distribution. Earlier exploratory programs (1) using gaseous fuels showed a trend toward higher local exit temperatures as the Btu/SCF levels were decreased below 600 Btu/SCF (22.3 MJ/M 3 ). These higher gas temperatures were suspected to be the result of increased discharge velocities exiting the dome associated with the increased volumetric flow of the lower Btu gas mixtures. Any such increases can adversely impact turbine section life. 4

5 To enhance the likelihood of success with the very low Btu content gases, the standard LM2500 combustor was modified for the initial tests. The swirl cup venturis (see Figure 3) were removed to reduce the local gas velocities and smooth out the velocity distribution exiting the dome. Earlier versions of the LM2500 combustor operated satisfactorily without the use of venturis, which were primarily added to provide reduced fuel nozzle carboning tendencies with liquid fuels. Initially, a combustor exit temperature performance test was conducted with methane gas to provide a benchmark for comparison to when the design is operated on gasifier fuel compositions. The test sequence was to then conduct a flammability test at the more favorable test conditions simulating high power operation. If satisfactory results were obtained, the exit temperature distribution was measured to assure acceptable temperature patterns entering the engine turbine nozzle. Following satisfactory completion of these two very important tests, the flammability characteristics at conditions simulating lower engine power operation was determined. The completion of this first phase of testing was intended to determine the acceptability of a modified LM2500 combustor to operate with a low Btu gas representative of a gasifier system. A similar second phase of testing was formulated to evaluate the standard LM2500 combustor equipped with the venturi, in the event the test results obtained from the first phase were favorable. Test Conditions The combustor test conditions were selected to simulate operation at rated power, a switchover from a starting gas to low Btu gas for a standard day and switchover on a cold day. The flammability tests were run at the correct combustor inlet temperatures and velocities but at ambient pressure. The lower pressure conserves gas usage and provides more pessimistic results relative to flameouts at true pressure. Measurements of the exit temperature distribution for the LM25OU combustor have always been conducted at ambient pressure and have provided excellent correlation to engine experience. The test conditions for the combustion stability tests are shown in Table 2. Each of the fuel compositions shown are representative of a gasifier fuel composition. At each test condition, steady state burning was established with the pure combustible gases and nitrogen gradually added until instability and flameout occurred. Each test point was evaluated several times to assure repeatability. The test conditions for the exit temperature performance evaluations are as shown in Table 3. The test was conducted at constant heat output conditions corresponding to the maximum power output conditions for the engine. The data were measured using four chromel/alumel (C/A) thermocouple rakes located at the exit of the combustor as shown in Figure 8. A total of 240 circumferential locations and seven radial positions were measured for a total of 1,680 individual measurements of the exit annulus temperatures. The temperatures were measured for a gas composition representing the lowest heating value fuel (150 Btu/SCF) (5.6 MJ/M 3 ) representative of a gasifier process. TABLE 2 - GASIFIER FUELS STABILITY TEST MATRIX P3= 1 atm CO/H2=2.4 TEST CONDITIONS Wc-pps (Kg/s)I ± ) FUEL GAS CON POSITION HEATING VALUE B SC IMJ H 3 ) RATED POWER STD DAY 5.9 (2.67) 1266 (703) H 2CO (21) (694) 2U 48 (24) (816) (29) (957) CH 4 38% 225 (ti.4) (345)(pph) 32 (312) 26 15U (5.6) (273) SWITCHOVER STD DAY 6.5 (2.95) 1154 (641) (19) (blb) (3U6) 225 (8.4) (22) (724) (274) (26) (849) (242) 15U (5.6) SWITCHOVER 7.1 (3.22) 1000 (556) (17) (566) (282) zz5 (8.4) (-20F DAY) (2U) (b68) (255) (24) (783) (223) 150 (5.6) 5

6 TABLE 3 - GASIFIER FUELS-EXIT TEMPERATURE PROFILE & PATTERN FACTOR TEST SCHEDULE P3 = 1 atmosphere BASELINE TESTS Wa T3 Wf pps (Kg/s) of ( C) ppn (Kg/s) FUEL LM2500 PERFORMANCE TEST 6.54 (2.97) 1000 (538) 530 (.063) CH4 LM2500 SIMULATION 7.07 (3.21) 800 (430) 535 (.U67) CH4 27.5Khpr. Std. day GASIFIER FUELS TEST LM2500 SIMULATION 5.85 (2.65) 806 (430) (3202 H2/CO/CH4 27.5K hpr. std. day 6TU/sec.)* *FUEL FLOW AND COMPOSITION TO BE ESTABLISHED FROM STABILITY TEST. LM2500 combustor with the venturi removed followed by a second series of tests with the standard LM2500 combustor, which is equipped with the venturi. The sequence of tests per-, ^' y-; R, - formed i s shown in Table 4. Flammability Results The flammability results for the two LM2500 combustor configurations tested are shown in Figures 9 and 10. The flammability ', ;V characteristics are shown both as a function of engine operating condition and percentage of H2/CO in the combustibles. As shown, the (ti = flameout levels are below the minimum Btu levels established for the range of conditions Y tested. As expected, as the combustor inlet ^ LM2500 Gasifier Fuel Test P3 r AMB 200- (7.45) N2 Addition R ^R d y M E L Incipient Blowout T3 ' 1000R(555K) of c^ ^^ _^0-_^f m +--T«1154R(647K G- / Blowout Combustor Exhaust Gas Temperature Traverse Mechanism 1001 (3.72) 0 T3 ^ 1260R(700K) TEST RESULTS The test was conducted in two phases. The initial phase consisted of flammability and exit temperature performance tests of the i % H2/CO IN Combustibles Figure 9 - Flammability Results for the LM2500 Combustor with No Venturi 6

7 TABLE 4 - TEST SEQUENCE PHASE I - NO VENTURI T3- F ( C) FUEL TYPE OF TEST CH4 EXIT TEMPERATURE CH4 EXIT TEMPERATURE CU/H2/CH4 FLAMMABILITY CO/H2/CH4 EXIT TEMPERATURE CO/H2/CH4 FLAMMABILITY CO/H2/CH4 FLAMMABILITY PHASE II - WITH VENTURI CO/H2/CH4 FLAMMABILITY CO/H2/CH4 FLAMMABILITY CO/H2/CH4 FLAMMABILITY C0/H2/CH4 EXIT TEMPERATURE /H2 FLAMMABILITY CO/H2 FLAMMABILITY CO/H2 FLAMMABILITY ]0) 160_IS.96) Biow out F Incipient Blowout - O J_ 1260R OOKI O 4^ 6' N O 3 - i i59 Rf641K ]2) $ `. - ' ---^^ S )\.^ % 8 2 CO IN Combustibles Figure 10 - Flammability Results for LM2500 Combustor with Venturi temperature becomes more favorable and the H2 content increases, the flameout margin improves. Based on the test results, tiie LM2500 engine would operate satisfactorily in either of the combustor configurations using these low Btu fuel compositions. Pattern Factor/Profile Results Measurement of the combustor exit temperature distribution was obtained using the standard procedures for evaluating the performance of aircraft engine combustors. The same thermocouple system, data acquisition, and data reduction procedures were used throughout this portion of the testing. Since the first test was conducted on the LM2500 combustor with the venturi removed, a calibration test was conducted using pure methane for comparison to earlier test data for the standard combustor when equipped with a venturi. The results are shown in Figure 11. The two parameters which characterize combustor exit temperature are profile and pattern factor. Profile represents the average of the temperatures at selected radial locations in the combustor exit. Pattern factor represents the highest individual temperature measured at any of the selected radial rn x C ae Low BTU Gasifier Test LM2500 Baseline - No Venturi Exit Temperature Performance Combustor Air Flow pps(2.96kg/s) r 0 A 1 Nozzles 60 ^ CH4 Fuel o Profile 0 40 Pattern Factor T3.0 Avg F (532.9 C) n 0 L_ l_ 1 _ I Tlocal-Tavg/L\Tavg Figure 11 - Performance Test Results locations. Profile impacts downstream rotating parts whereas pattern factor affects the stationary parts downstream of the combustor. The profile and pattern factor data for the combustor with the venturi removed is typical of the experience level for the standard design when operating on natural gas. At the lower combustor inlet temperature associated with the LM2500, the profile is similar to the results at the higher combustor inlet temperature (T3) since temperatures are normalized. However, the pattern factor results are generally higher as shown in Figure 12. This is not unexpected since the average exit temperature rise (Q T) and the average exit temperature (T4) are lower. Therefore, a hot streak that emanates 7

8 I from a stoichiometric region in the dome would most likely result in a nigher absolute temperature at the exit. The lower LS T and T4 would result in a higher pattern factor. Low BTU Gasifier Test Exit Temperature Performance LM2500 Baseline - No Venturi C om bustor Air Flow -_ T3_.0 Avg F pps 3.2_ORg/S^ T E- Al Nozzles CH4 Fuel 260-4) x Profile Pattern Factor 0 40 C Q 20 _10 ii -_ Tlocal-Tavg//Tavg Figure 12 - Performance Test Results The results from the combustor test without the venturi when tested with the lowest Btu gas composition are shown in Figure 13. The pattern factor has increased over the levels with pure methane. As mentioned earlier, this increase was not unexpected based on experience with medium Btu gases. Since the fuel-to-air mass ratio has increased by a factor of 3, the mixing process will take longer, resulting in some gas reaching the combustor exit at a higher absolute temperature. LM No Venturi mkr. 7 Kg/^0 Av.6 Combustor 2r (2 I. S 3 80^ V^ O o O Profile 1 Pattern Factor =60r A4 Nozzles B/SCF Gasifier Fuel 20- O 0o O : = E.3.4 TbcaFTavg/LTavg Figure 13 - Performance Test Results Surprisingly, the standard combustor design equipped with the venturi did not increase in pattern factor significantly as shown in Figure 14. Based on earlier tests (1), pattern factor exhibited a rapid increase with decreasing Btu content. This rapid increase was suspected to be related to the higher velocities of gas exiting the swirl cup, preventing ample mixing time of the gas with the surrounding combustion air. Although some increase did occur in these tests, the iripact was not as severe as expected. LM2500 Combustor Air Flow pps T3.0 Avg F Kg/s) c._ 4) >. 80Lc Z> o o Profile Pattern Factor 60 - A4 Nozzles ae 40 i11 50 B/SCF Gasifier Fuel 20; ro. 0l _ i _- i Tlocal-Tavg/LTavg Figure 14 - Performance Test Results Predicated on these test results and those obtained earlier in the medium Btu gas tests of the LM2500, there is a general trend, as shown in Figure 15, of increased pattern factor with increased swirl cup loading with gaseous fuels. As the swirl cup volumetric flow increases, the exit velocities into the dome increase reducing the residence time for primary zone combustion air and dilution air to interact resulting in high absolute temperatures at the exit. 227(8.45)0 Tic 800F(427C) ' 4" 151(5.62) 151(562) 151( (12.10) -^T3= 1000F(538C) o^ /350(13.03) o.3 911(33.9) O 425(15.82) BTU/SCF(MJ/m3).. 911(3 ii 0 ^a 0650(24.20) c 83)10.4) 911(33.92) d / Ll C 3 H8 (Ref 1) (33.92) CH4 (Ref 1) L H 2-00-CH 4 p H 2 -co Flag - No Venturi Ofuel Ft3/sec m 3/s^ Swirler Fuel/Air ' Qair - Ft3/sec \m /s, Figure 13 - Effect of Swirler Loading on Pattern Factor This test program represents the first successful demonstration of the operation of a LM2500 combustion system with a low Btu gas containing CO and H2. Based on this test and earlier test programs, the LM2500 combustor has demonstrated flammability and performance capability to operate with gases containing H2/C0/CH4 down to 150 Btu/SCF (5.b MJ/M 3 ) and operation down to about 300 Btu/SCF (11.2 MJ/M 3 ) on CH4 based fuels. OL 8

9 CONCLUSION The results of this full annular test program demonstrated the capability of the LM2500 combustion to operate at maximum output conditions when supplied with a low Btu composition representative of a coal gasification process. Although some degradation in pattern factor occurs in the standard design as a result of the higher volumetric gas flows, operation of the engine at maximum power output with the current combustion system with appropriately sized gas nozzles appears completely viable. Some adverse impact on the turbine life may result from the higher pattern factor, however, these effects could be offset partially by introduction of turbine nozzles with improved cooling. REFERENCES 1.0 Battista, RA, Pandalai, RP, Hilt, MB, "Low Heating Value Fuel Burning Capabilities of General Electric Industrial Gas Turbines", ASME 82-GT