Cooper-Bessemer coal-fuelled LSC-6 engine

CONSElL INtERNATIONAL

20th INTERNATIONAL CONGRESS ON COMBUSTION ENGINES

COOPER-BESSEMER COAL-FUELED

.LSO-6 ENGINE

by A K (Kam) Rao

COoperlBessemer Reciprocating Products, USA. and

Robert P Wilson

Arthur D Little Incorporated, 'U.S.A.

LONDON 1993

INTERNATIONAL COUNCIL

ON COMBUSTION ENGINES

©CIMAD 1993

Depuis 1985 Cooper-Bessemer et Arthur D. Little, ils developpaient la technolegie

pour l'utilisation du melange de l'eau de charbon (CWS) dans les moteurs immobiles

alternatives a combustion interne. Les applications de la generation du pouvoir modulaire du modele 10-100 MW sont les buts des applications pour la fm des amides 1990 et celles apres ce temps, quand les prix d'huile et ceux du gaz naturel s'attendront a augmenter. Comme une

partie de cette programme, plus de 750 heures de l'operation du moteur prototype se sont

realisees stir le CWS. Un essai demonstratif de 100 heures du moteur grandeur nature LSC de 6 cylindres integre avec le Systeme de Contrale des Degagements aura lieu en 1993. Les

recherches de ces auteurs-ci dans ce document ont pour but de &erne (a) le nouveau

carburant de moteurs (b) la nouvelle technologie des moteurs (c) le systeme de contrOle des

degagements.

DOT

COOPER-BESSEMER COAL-FUELED LSC-6 ENGINE

A. K. (Kam) Rao, Project Manager Cooper-Bessemer Reciprocating Products

Grove City, Pennsylvania, U.S.A. Robert R Wilson, Vice-President

Arthur D. Little Incorporated 'Cambridge, Massachusetts, U.S.A.

ABSTRACT'

Since 1985, Cooper-Bessemer and Arthur D. Little have been developing techonology

to enable coal water slurry (CWS) to be utilized in stationary, reciprocating internal

combustion engines. Modular power generation applications in the 10-100 MW size are the

the target application for the late 1990's and beyond, when oil and natural gas prices are

expected to increase. As part of this program, over 750 hours of prototype engine operation has been achieved on CWS. A 100-hour demonstration run of the 6-cylinder, full scale, LSC

engine with integrated Emissions Control System is planned for 1993. In this paper the authors describe (a) new engine-grade fuel; (b) the novel engine technology; and (c) the

INTRODUCTION

Over a hundred years ago Rudolf Diesel experimented with coal dust to operate an engine. Although Diesel was discouraged by the results, some of his associates continued the work and by 1940's Germany was operating engines burning coal dust [1]. Between the end of the World War II and the early 1980's was a slow period for coal fueled engine research.

However, interest in coal fueled heat engines revived after the fuel price hike in the 1970's. Based on the advances in materials technology, coal fuel processing and success of micronized coal water slurry combustion tests in an engine in the early 1980's, Morgantown Energy Technology Center of the U.S. Department of Energy initiated several programs for

the development of advanced coal-fueled diesel and gas turbine engines

for use in

cogeneration, small utilities, industrial application and transportation [21,[3].

Since 1985, Cooper-Bessemer and Arthur D. Little have been developing techonology

to enable coal water slurry (CWS) to be utilized in

combustion engines. Modular power generation applications in the 10-100 MW size are the

the target application for the late 1990's and beyond, when oil and natural gas prices are

expected to increase. As part of this program, over 750 hours of prototype engine operation has been achieved on CWS. A 100-hour demonstration run of the 6-cylinder, full scale, LSC

engine with integrated Emissions Control System is planned for 1993. In this paper the

authors describe (a) new engine-grade fuel; (b) the novel engine technology; and (c) the

emissions control system.

ENGINE GRADE COAL WATER SLURRY

Coal Water Slurry Specification

The coal water slurry consists of approximately 50/50% by weight of finely powdered coal and water. The ash content of the coal before it is made into a slurry is the most important parameter of the CWS specification. During the early stages of the project the ash

content was limited to 0.4% on dry coal basis in order to ensure the success of engine

operation on CWS. However, expensive chemical cleaning methods had to be used in order

to achieve this low level of ash content. As CWS operating experience was gained on the single cylinder laboratory JS engine, the ash content limits of the CWS were gradually

relaxed. Currently ash content in the range of 1.5 to 2.0% on dry coal basis is considered

acceptable. This level of ash content can be achieved by less expensive physical cleaning

processes, without resorting to chemical cleaningmethods.

Another important CWS property is the change in viscosity with shear rate. At the time of injection of CWS into the combustion chamber, the CWS is subjected to very high

shear rates in order for all the fuel to be introduced into the combustion chamber over an

optimum duration during the cycle. If there is a substantial increase in viscosity at high shear, rates, problems in fuel flow through the injector could occur.

The engine was tested with a range of solids content of the CWS, from 44-54% and

the engine could tolerate a wide range in solids content. Similarly the engine is not very sensitive to top coal particle size in the CWS (up to 120 microns). While CWS to a wide

range of specifications was tested, the properties listed in Table I may be considered typical of the fuel used in recent tests.

Table I

CWS Storage and Supply

In the early days of the single cylinder JS engine operation on CWS, 200L barrels were used as fuel supply tanks. With reliable operation of the engine for long periods of time a 2,000L tank was constructed as a storage tank for the JS engine and operating experience

was gained in long term storage and mixing of CWS. Based on this experience a 25,000L storage tank was built for the 6-cylinder LSC engine. The tank was designed for outdoor

installation and is an insulated, stainless steel horizontal cylindrical tank. If necessary the

tank could be heated in the winter months to maintain the CWS _{at required temperature.}

There are five man-holes at the top along the length of the tank, for visual inspection of the tank contents. Most importantly, the tank is fitted with a novel CWS recirculating system that

would keep the CWS as a homogeneous mixture of uniform heat value for _satisfactory

operation of the engine.

The recirculation system operates by drawing the CWS from the top of the tank by

a variable height, floating CWS intake pipe, as shown in Figure 1, by the recirculation _pump. made by Blackmer, of the positive displacement, vane type. The CWS is pumped hack into

a jet mixer, a 102 mm diameter round pipe at the bottom of the storage tank. There are a number of 5 mm diameter holes on both sides of the jet mixer pipe. CWS passes through

these holes at high velocities to enter the main chamber of the tank,

Coal Water Slurry Properties

Coal Analysis Coal Content 49.24% Water Content 49.25% Additives 1.51% Viscosity @ 100-200 s4 50-100 cp Viscosity @ 1,000 s' 100-300 cp

Mean Particle Size 12 microns

99.9% Less Than 44 microns

100.0% Less Than 88 microns

Ash Content 1.8%

Sulphur 0.6%

Volatiles 38.5%

RUSH NATE*

4.

FLOAT (14LJ,OPO.Ao0

C 3 (1,42LAATID) 33. RECIRCULATION PLAN, FRAIN DUMONT

OF.AR 3UPRORT DRAIN

TO ENGINE DAY TAM FIGURE 1 RETURN MOM ENOWIE DAY TAW vALVE L. BALL VALVE BT BUT Tfpfly vALyE

Intermittent operation of the CWS recirculation pump is adequate to keep the slurry

well mixed. Because the storage tank is well insulated, even when outdoor temperature falls to -15°C, if the recirculation pump is operated on a one hour on, one hour off schedule, the pump adds enough energy to the CWS to maintain its temperature in the tank at about 14°C. A transfer pump, a smaller version of the recirculating pump, is used to draw CWS from the recirculating loop to fill a 400L day tank. An automatic level controller in the day tank would maintain the CWS level in the day tank.

DIESEL ENGINE MODIFICAITONS FOR COAL FIRING

JS-1 Engine

For initial development work, the laboratory single cylinder JS engine was used. After

perfecting the CWS operation on this engine, the production type 6-cylinder LSC engine is currently being used. The parameters of the two engines are compared in Table II.

Table II

Parameters of the Test Engines

Model is-1 LSB-6/LSC-6

Bore 330.2mm 393.7mm

Stroke 406.4mm 558.8mm

Nominal Speed 400 rpm 400 rpm

No. of Cylinders 1 6

BMEP 10.4-13.8 bar 14.3 bar

Cycle 4 stroke 4 stroke

Power Output 120-160 kW 1952 kW

The JS engine proved to be an excellent vehicle for the early research and

development work. It had the same operating speed as the LSC engines, which are the coal fueled engines to be commercialized. The CWS injection and combustion characteristics were expected to be very sensitive to engine operating speed. The combustion chamber size and shape were close enough to the LSC that scaling up was not expected to be difficult. In place

of a turbocharger, a separately driven compressor was used to supply combustion air to the engine. This feature, together with the facility to heat or cool the combustion air supplied to

the engine enabled the simulation of a wide variety of inlet manifold air conditions. An orifice plate in the exhaust manifold simulated the normal back pressure offered by the

turbocharger.

A Hewlett Packard computer with a high speed data acquisition unit was used to scan and record all the required pressures and temperatures, engine speed, load, etc. in digital form for post processing. _{In parallel with the data acquisition unit was an oscilloscope and a} fourteen channel FM data recorder which was used to "play back" any specific engine run.

Flywheel timing, combustion and fuel injection pressures were also recorded in digital form. The exhaust duct was fitted with a heated sample line. Emissions analyzers determined and recorded the levels of various exhaust gas constituents.

The JS engine operation helped to identify and resolve the problems in CWS handling,

injection and combustion, as well as to develop highly durable combustion chamber

components. Also the testing was helpful in identifying the levels of pollutants in the

untreated exhaust gas, thereby establishing realistic design targets for the emissions control

system.

Based on the operating experience of the JS engine, the 6-cylinder production LSB engine was converted for operation on CWS and was designated as LSC-6 engine.

LSC Engine

With the heating value of the slurry approximately half that of the diesel fuel, the fuel

injection pump needed to deliver approximately twice the volume of CWS, compared to diesel

fuel, in about the same duration, in order to develop the same horsepower as the diesel

engine. The fuel injection pump on a standard LSB engine has a 26 mm plunger and barrel. The fuel injection pump selected for CWS operation has a plunger and barrel of 36 mm. The

the normal operating value is around 69-83 MPa.

This combination of higher injection pressure acting on a larger plunger area resulted in a substantially higher loading on the camshaft which necessitated the increase of camshaft diameter from 105 to 165 mm. The cylinder block that holds the camshaft and cam follower gear and fuel injection pumps was redesigned and substantially stiffened to accommodate the larger components and higher loads.

The 'cylinder block was the only major casting to be redesigned. No changes were

needed to the base, centerframe, crankshaft, main and connecting rod bearings, connecting rods or air intake manifolds. The LSB-6 engine is shown in Figure 2.

FIGURE 2

Cylinder Head

The central hole in the cylinder head had to be slightly enlarged to accommodate the coal fuel injector. The location or size of the air inlet and exhaust valves has not been changed. The jet cell openings in the cylinder head were used to accommodate the diesel

pilot injector hardware. The result is that the cylinder head for the coal-fueled engine can be machined from the same casting as the cylinder head for the diesel fuel engine. Because the two-cylinder heads are virtually identical, it is not anticipated that the CWS cylinder head would suffer any undue mechanical or thermal stresses if the peak firing pressures are kept within design limits.

ra -

ilio

,

MI

r,i

Piston

The bowl type combustion chamber used during the JS engine tests gave remarkably good results. This is the standard combustion chamber shape on the LSB engine and was

retained on the LSC engine. The piston is made in two pieces, with a forged steel crown with forged aluminum skirt.

Injection System

Although auto-ignition of CWS is possible and demonstrated on the JS engine [4], a small quantity of diesel pilot, (2-5% of total heat input) reduces the manifold air temperature required for timely ignition and combustion. Therefore the LSC engine was equipped with two fuel systems, a CWS main injection system and a diesel pilot fuel injection system. Main Injection System

As shown in Figure 3, a conventional cam driven 36 mm jerk pump operating on

diesel fuel provides the fuel injection timing and metering function as well as the hydraulic driving pressure for CWS injection into the combustion chamber. This is a scaled up version of the system used on the JS engine, as described in Reference [5].An isolating piston in the CWS injector separates the jerk pump from the CWS supplied to the injector from the day tank at low pressure (l,400-2,000kPa), through a pair of nonreturn valves. The CWS injector is located centrally in the cylinder head as shown in Figure 4.

DF2 driving fluid Diesel fuel injection pump f1I cylinder: head El '1117

FIGURE 3 FUEL INJECTION SYSTEM

Isolating piston

Double check valve CWS supply pump

Coal water

slurry supply

"Jet Cell"

Piston

Coal Slurry

Injector

FIGURE 4 COMBUSTION CHAMBER

Pilot Injection System

In addition to the main injector, Figure 4 also shows the two pilot injectors that were tested at different times. Any one type of pilot injector was used at any given time. In the

left port is a jet cell. Both natural gas and diesel fuel were used to start a flame in the "jet cell" or precombustion chamber. The flame and hot gases emerge from the jet cell orifice into the main combustion chamber, igniting CWS. The details of the jet cell operation are

discussed in [6] and [7].

In the right port is shown a conventional 6 hole x 0.27 mm pilot nozzle that would

inject diesel fuel directly into the main combustion chamber. Most of the recent work was

done using two diesel pilot injectors per cylinder head, injecting the fuel into the main

combustion chamber. The fuel to the diesel pilot is supplied by an auxiliary fuel pump, chain driven from the engine camshaft.

Performance

Initially the LSB engine was operated with the #1 cylinder operating on CWS with the other five cylinders operating on diesel fuel as described in 161. After optimizing the combustion performance by refining the CWS injector nozzle tip parameters, the LSB engine

was converted to LSC engine (for CWS operation), using the new cylinder block and

camshaft and 36 mm fuel pumps. All the cylinder headswere fitted with CWS injectors and diesel pilot injectors.

An extended break-in procedure was used to break-in the new piston rings and

cylinder liners, both of which were coated with wear resistant materials. The engine was then operated on CWS, initially to verify the load carrying capacity of the engine. The load was gradually increased from 150 to 175 and 200 psi bmep. The preliminary results were very

encouraging. Figures 5 and 6 show the cylinder pressure traces for all the 6 cylinders

operating on CWS at 172 psi and 199 psi bmep. The engine operation confirmed the ability

of the engine to operate on CWS and produce the same power output as a

Diesel Pilot

Injector

It

1350 t200 t050 900 750 500 450 300 Cyl.Cy/. P Cyl. Fr. Cyl. Pr. 44

150- - -

_{---tyl. Pr}

Htnri Awl en' ILI', 41 ,111111111011I pi al

C17 1521e 1:350 1300 40504-900 750 500 450 300 150

FIGURE 5. CYLINDER PRESSURES AT 172 psi bmep. 0 ru rri in up II,-Cl irn rn PD M' JPD rn CRANKRNGLE Degrees 1124 1519 LOG 575 Line 6 RPM see EttEP 17a HP 1 3512 2 US 2212 220 220 0 1124 tG42 Log 575 Line re PH 400 P 199 Cyl. yl. Pr. yl. Fr. 43 1. Pr. 44 01 0 0 N

0GD

n

FIGURE 6. CYLINDER PRESSURES AT 199 psi bmep.. LSB CYLINDER PRESSURE DATE

LSBHCYLINDER PRESSURE DATE

CRANKRNGLEDegeeev.

ht

CI

0

I . Pr. 40

110111.111.1 Ulilleillotinnutticirmettlitti, tilintv, ilthl tit L., Ilanialornill

41 IPP\457 INP IHP 4 IHP 5 4 454 -Cyl. Pr. 45

_

Fuel Injection Pump

Nozzle Tip'

Injection Timing Pilot

Piston Rings/Cylinder Liners

The preliminary performance data is given in Table IV.

Table IV Preliminary LSC-6 Performance Data on CWS.

diesel/natural gas, dual fuel engine. Based on these results, the injection system is being fine

tuned to minimize the cylinder to cylinder variation in power output.

given in Table III.

Table III

36 mm Barrel and Plunger

19 holes x 0.633 mm Diameter with Sapphire Inserts

23° BTC Port Closure

Two Diesel Injectors' Supplying, 4-5% 'of Total Heat Input

Wear Resistant Coatings

Considerable development effort was involved in designing a low wear CWS injector

nozzle, piston rings, cylinder liner and exhaust valves. These efforts were described in

References [8] and [9].

EMISSIONS CONTROL SYSTEM

Although the NO emissions of the coal diesel' engine are remarkedly low, an emission control system was designed not only to control SO2 and "fly ash", but also to further reduce NO in anticipation of future NO standards. Currently there are no prescribed limits for the

10Y Lem Speed (rpm) 400 400 400 Bmep (bar) 10.3 12.1 13.8 Power at Flywheel, 1,410 1,641 1,880 (kW) Cylinder Exhaust 466 477 493 Temp (°C) Specific Fuel 101600 9,546 9,475 Consumption (kJ/kW.h LHV)

ID fan

emissions from a CWS fueled diesel engine. Therefore the New Source Performance

Standards (NSPS) for coal-fueled power plants was used as a guide for setting the emissions targets for the LSC-6 engine. Both the NSPS limits and the emissions targets for the program are given in Table V.

Table V Emissions Targets and NSPS Limits

The layout of the Emissions Control System (ECS) for the LSC-6 engine is shown in Figure 7. The system comprises of the following seven subsystems: In Cylinder NOx reduction, cyclone, selective catalytic reduction (SCR) reactor, sorbent injection system,

baghouse and induced draft (ID) fan.

Bag house ECS stack Ammonia tank Control room Mixing venturi Sorbenl hopper _Heat exchanger Turbo-charger SCR reactor 1 LSC6 coal-fueled diesel engine

FIGURE 7. INTEGRATED EMISSION CONTROL SYSTEM

Pollutant Control Methods Emission Target

New Source Performance

Standards

NOx Water Injection (CWS)

Combustion Optimization Selective Catalytic Reduction Dry Sorbent Injection

86 mg/MJ 259 mg/MJ

SOx Coal Cleaning

Dry Sorbent Injection

215 mg/MJ 517 mg/MJ and 90% reduction Particulates Cyclone Baghouse 6.5 mg/MJ 12.9 mg/MJ NOx I SOx Part.

I-1

Engine exhaust gas Ammonia 'injection

anew

igliclINIMON

In operation, exhaust gas from the engine first enters a cyclone where relatively large

particulate matter is removed. Gas exiting the cyclone goes to the engine's turbocharger

where the temperature and pressure are reduced to about 455°C and 510 mm water gauge

rr: (w.g.) respectively. The first subsystem in the ECS is the SCR reactor where NOx is reduced.,

by about 85%. Then, exhaust gas enters the heat recovery steam generator(HRSG) which reduces the gas temperature from about 455 to 175°C. After the HRSG, exhaust gas from the two engines are combined and sorbent is injected into the gas in a mixing venturi, reducing SO2 by about 80%. The exhaust gas and sorbent mixture enters the baghouse where the sorbent is removed from the exhaust gas. After the baghouse, the clean exhaust gas flows through the ID fans and to the stack. Major components of the ECS are discussed below.

'.Cyclone

The cyclone is designed to remove about 80% of particles having diameters of 20 pm and about 50% of the 5 pm particles. The low pressure loss (about 150 mm w.g.) across the cyclone ensures minimal impact on turbocharger and engine performance. Cleaned gases exit from the top of the cyclone and flow to the turbocharger, while solids exit the bottom of the cyclone through a rotary valve.

Selective Catalytic NOx Reduction System

The SCR system, illustrated in Figure 8, reduces the concentration of NO and NO2 in the exhaust gas by reaction with ammonia over a ceramic zeolite catalyst.

L

Mass flow control

Anhydrous ammonia for the system is stored on site as a liquid in a 2000L tank at 345 to 1200 kPa. Ammonia vapor is drawn off the tank, reduced in pressure, and then injected into the exhaust gas just upstream of the SCR catalyst. The mixture of ammonia and exhaust gas enters the reactor from the top at 455°C, flows down through the catalyst and exits at the

bottom. Catalyst space velocity is about 6800 111 at full engine load. With an inlet NOx

concentration of 500 ppm, about 21.4 kg/h of ammonia is required for 85% NOx reaction at full engine load.

'Sorbent Injection System,

The sorbent injection system, illustrated in Figure 9 reduces the concentration of SO2

in the flue gas by reacting SO2 with sodium bicarbonate (NaHCO3) particles. Sodium

bicarbonate sorbent, supplied from the hopper through a rotary valve, is entrained in air

supplied by a separate blower and carried to the mixing venturi.

To stack Dry Injection system Blower Exhaust gas 7, egrn Rotary' air lock Compressed air

PP e

1-1111 1-0

'ad air lock

Baghous,e

FIGURE 9. SORBENT INJECTION SYSTEM AND BAGHOUSE

Exhaust gas at about I75°C enters the venturi where the flow converges into the throat creating a higher velocity mixing zone. Sorbent is injected into the exhaust gas in this region.

The flow then expands and enters the baghouse. About 270 kg,/h of sorbent is required when the engines operate at full load.

Baghouse

The baghouse, also illustrated in Figure 9, separates ash and sorbent particles from the

exhaust gas, and provides additional contacting time for removal of SO2 by the sorbent..

Al

Bag dump hoppe

Exhaust gas enters the baghouse plenum beneath the filter bags. Gas flows upward,through the bags, and into the outlet plenum. As the gas flows through the filter bags, particulate is collected on the outside of the bags. The bags are periodically pulsed with air, causing the

particles to fall into a hopper below the bags. Ash is continuously withdrawn from the

hopper through a rotary valve and discharged into a collecting bin for disposal.

The initial testing of the emissions control system has demonstrated that the SCR and sorbent injection systems are able to meet the program's NOx and SO2 reduction performance

goals. Total NOx reduction of about 90% and SO2 reduction of about 75% are expected

when the LSC-6 engine operates on CWS.

Summary

The technology for burning coal in diesel engines has been developed and over 750 hours of coal-fueled testing has been acheived with prototype engines.

The engine is tolerant to a wide range of solids content, mean particle size and other properties of CWS specification. The ash content of the CWS was relaxed to 1.5 to 2.0% ash from the 0.4% during early stages of engine operation.

A 25,000L CWS storage tank and circulation system were designed and installed for

the operation of LSC-6 engine. The slurry stays suspended for months with 1.5%

additive to the CWS.

A special injection system was designed to permit operation with CWS and was successfully tested on the JS-1 and LSC-6 engines. There was no damage to the

pump or injector tips.

The LSC-6 engine was modified for operation on CWS. The engine operated

satisfactorily on CWS, at full speed and full load as well as full speed and part load

conditions.

Emissions control equipment was designed and installed to suit the full power output of the LSC engine. Preliminary results indicate that the emissions reduction targets are met.

ACKNOWLEDGEMENTS

We acknowledge the guidance and suggestions of W. Cary Smith, Technical

Representative, of Morgantown Energy Technology Center of the U. S. D.O.E. A special

thanks is due to Larry Carpenter, the first Technical Representative of METC for our project. A number of individuals including Charles Benson, Eric Balles, Karen Benedek, and Ron Mayville at Arthur D. Little; Fred Schaub, Jesse Smith, Terry Baker, and Charles Melcher of

Cooper-Bessemer as well as individuals at other participating companies including Jack

Kimberly of Ambac International (Fuel Injection Systems), Steve Johnson of PSI Technology Co. (Emissions Control Systems), Jim Parkinson of CQ Inc., Clay Smith of Otisca and Amax

14

15

(CWS Fuel and related activities); Lee Dodge and Tom Ryan of Southwest Research Institute, (Fuel Atomization Studies) have contributed significantly to the success of this project.

REFERENCES

1111 Soelmgen, E.E., "The Development of Coal Burning Diesel Engines in Germany: A

State-of-the-Art Review," Report prepared for the United States Energy Research and Development Administration, Report PE/WAPO/3387-1, August, 1976.

[2]'

Carpenter, L.K., and Crouse, F.W., Jr.,

Challenges," ASME Paper 86-ICE-6, February, 1986.

In

McMillian, M.H., and Webb, H.A.,

,[4]

_{Rao, A.K., Melcher, C.H., Wilson, R.P., Jr., Balles, RN., Schaub, F.S., and}

Kimberley, J.A., 1988, "Operating Results of the Cooper-Bessemer JS-1 Engine on Coal-Water Slurry," ASME Journal of Engineering for Gas Turbines and Power, Vol.

110, pp. 431-436.

131 Rao, A.K., Wilson, R.P., Jr., Balles, E.N., Mayville, R.A., McMillian, M.H., and

Kimberley, J.A., 1989, "Cooper-Bessemer Coal-Fueled Engine _{System--Progress}

Report," Coal-Fueled Diesel Engines, ASME ICE-Vol. 7, pp. 9-17.

[61 _{Rao, A.K., Balles, EN., Wilson, R.P., Jr., "Features and Performance Data of}

Cooper-Bessemer Coal-Fueled Six-Cylinder LSB Engine," ASME _{ICE-Vol. 16, pp. 11-16;} ASME Journal of Engineering for Gas Turbines and Power, Vol. 114, 1992, pp. 509-514.

Blizzard, D.T., Schaub', F.S., 'Smith, LG., "Development _{of the Cooper-Bessemer}

CleanBumn4 Gas-Diesel (Dual-Fuel) Engine." _{ASME ICE Division Technical}

Conference, Fuels, Controls, and Aftertreatment for Low Emissions Engines, ICE-Volume 15, p. 87-97, October, 1991.

Mayville, R.A., Rao, A.K., and Wilson, R.P., Jr., 1990, _{"Cooper-Bessemer}

Coal-Fueled Engine System: Recent Developments in Durable Components," Coal-Coal-Fueled Diesel Engines 1990,, ASME ICE-Vol. 12, pp. 17-22.

[91

_{Mayville, R.A., Rao, A.K., and Wilson, RT.,-}

Development Progress for the Cooper-Bessemer Coal-Fueled Diesel Engine," ASME Coal-Fueled Diesel Engines-1991, ICE-Vol.. 14, pp. 23-27.

DO]' _{Balles, E.N., Benedek, K.R., Wilson,, R. P., Jr., and Rao, A. K., 1987 "Analysis of}

Cylinder Pressure and Combustion Products From an Experimental Coal-Fueled Diesel,

Benedek, K. R., Menzies, K.T., Johnson, S. A., Wilson, R. P., Jr., Rao, A. K., and

Schaub, F. S., 1989, "Emission Characteristics and Control Technology for Stationary Coal-Fueled Diesel Engines," ASME Journal of Engineering for Gas Turbines and Power, Vol. 111, pp. 507-515.

Staudt, J. E., Itse, D. C., Benson, C., Wilson, R. P., Jr., Schaub, F. S., and Rao, A. K.,

1991, "Controlling Emissions From Stationary Coal-Fueled Diesel Engines," presented

at the Heat Engines Conference, Morgantown Energy Technology Center, June, 1991.

16