REPORT WBSSR 77- 1201(R)

EROSION FAILURES

IN COAL

CONVERSION PLANT

DANIEL R. BUTRYMOWICZ

Jan. 1977

Meta/iurg y Division

institute for

Materials Research

National Bureau of Standards •
-A
Erosion Failures in Coal Conversion Plants

Daniel B. Butrymowicz

Metallurgy Division

Institute for Materials Research

National Bureau of Standards

Washington, D.C. 20234

December 15, 1976

Erosion Failures in Coal Conversion Plants

Abstract

This survey was undertaken to make plant operators , contructors,

architectural engineers, and designers of coal conversion plants

aware of the existing erosion problems in present-day pilot plants

and process demonstration units. This publication surveys the

failure of pumps, valves, cyclones, transfer lines, etc. whose

mode of failure involved erosion.
'

v
This is a draft report which in

its present form is not intended for

circulation. It has not been approved

for circulation, publication, or public

distribution by either NBS or ERDAFossil Energy. It is presently undergoing official review at NBS as well

as at ERDA-Fossil Energy and will be

available shortly as an NBS Special

Publication. Until such time it should

neither be quoted nor the information

contained therein be used in any manner.

NBS and ERDA accept no responsibility

for damages that may result from the

use of information contained in this

draft report.
'

'
Erosion Failures in Coal Conversion Plants

by

Daniel B. Butrymowicz

Introduction

The erosive wear leading to failure of structural and mechanical

components of coal gasification and liquefaction pilot plants warrants

special attention from design, chemical, materials, and construction

engineers. If reliable and efficient coal conversion plants of

commercial size are to be constructed, the problems of wear and

abrasion presently being experienced in pilot plants will need to

be solved. Solutions to these erosion problems will vary, depending

on the particular operating conditions in these plants. Wear and

abrasion appears in chutes and pipes in those plant areas where

the sliding coal arrives and receives its pretreatment. Erosion

occurs in the gasifier with its high temperature corrosive gas

containing fly ash, char, dolomite, and other particulates, especially

where materials flow out at high speed through valves and fittings.

Downstream from the gasifier the hot corrosive particulate- laden

gas will move through transfer lines, cyclones, heat-exchanger

tubes, regenerators, turbines, and many other components.

The purpose of this summary report is to review failures due

to erosion that have occurred in pilot plants. Data on erosion

problems were extracted exclusively from the ERDA (Energy Research

and Development Administration) failure analysis reporting system

- 2

-

on materials and components. Most of the failures, data of which

are contained in the NBS/ERDA Information Center occurred in large

pilot plants 1975 and 1976 (data from a few earlier incidents also

are included). Failure data are available for eight different coal

conversion processes and encompass the ERDA's Synthane process, the

Institute of Gas Technology’s Hygas process, Conoco Coal Development

Company's CO2 Acceptor process, Pittsburgh and Midway Coal Mining

Company's SRC process, ERDA's Synthoil process, U.S. Steel Corporation's

Clean Coke process -and ERDA's Laramie Energy Research Center's

underground gasification process.

Details of the process chemistry, equipment, and operation of

each of the aforementioned processes can be found in reference [1]

and will not be elaborated on here. Only those details which are

directly involved with the erosion process will be mentioned.

Those pilot plants in advanced stages of development have had

a longer operating history and, as a natural consequence, will have

generated more erosion data for the ERDA failure reporting system.

Many processes are still in various stages of design and construction

while others have only begun to yield operating data for the materials

and components employed therein.

Failure data have proven to be most useful to plant constructors

and operators when categorized according to component (e.g., pumps,

valves, cyclones, etc.) and this format will be followed in assessing

failures surveyed in this document.

Pumps

In the coal preparation areas of pilot plants, coal feeding takes
V

'
-3-

place via slurries or pneumatic transport. These liquid/solid

slurries must be kept in motion with constant agitation to prevent

settling and the resultant clogging of pipes and other components.

Pulverized coal for the gasifiers is delivered as a slurry, using

light aromatic hydrocarbons for the suspension medium.

In the ICT Hygas gasification process, coal feed is introduced

to the high pressure hydrogasif.ier in the form of an oil/coal

slurry. The slurry consists of coal solids (up to 50 percent by

weight), sized from -10 to +80 mesh, in a low viscosity oil that

may reach up to 150°F. The slurried coal feed is brought up

to a pressure of 1000 psi by special reciprocating pumps, which

in turn are supplied by low pressure centrifugal pumps. To feed

slurry to the high pressure pumps, a continuous circulation loop

is maintained through the use of the low pressure centrifugal

pumps. These originally-installed centrifugal pumps were of cast

steel construction with all the wetted portions coated with a

plasma-sprayed abrasion-resistant coating (Noroc, a proprietary

hard coating, and tungsten carbide) [2]. Although such construction

is common and successfully used in oil and catalyst slurry pumps

in oil refineries, it failed in the Hygas pilot plant. The

proprietary coating that had not spalled off was subsequently eroded

away. The unprotected cast steel eroded soon after. Other types

of coatings and combinations thereof soon failed in a similar

erosive manner. A cast, Ni-hard lined, centrifugal slurry pump

was then substituted for the eroded pumps. Resistance to erosion of
.

1

. '

.

.
-4-

these Ni-hard pumps was very good. Although the erosion problems

were solved, these low-speed pumps could not maintain required

stream velocities and plugging resulted. The problem was solved

by returning to the original cast-steel pumps and applying a weld

overlay of Stellite-12 to the wetted parts. Great care was used

in cleaning the cast-steel surface prior to applying the Stellite-12

overlay. Additionally, pump speed was reduced from the initial 3600

rpm to about 1750 rpm. Erosion resistance has been improved by the

materials changes and reduced pumping speeds.

Analogous erosion problems in similarly designed cast-steel

centrifugal pumps were experienced in the high pressure water/char

slurry circuit of the Hygas pilot plant [3]. The originally employed

slurry centrifugal pumps were used to circulate the water-quenched

spent coal char from the bottom of the hydrogasifier. The water slurry

contained a 25 weight percent char concentration. As before, erosion

caused pump failures and was corrected in a similar manner, by

application of an abrasion-resistant Stellite-12 overlay to all

wetted parts with conventional welding techniques. Reduced pumping

speeds in the newly overlaid cast-steel pumps aided in the prevention

of 'erosion.

Although not a pump failure per se, the above-mentioned reciprocating pumps used to inject the coal/oil slurry into the high pressure

environment of the hydrogasifier experienced erosive failures of the

factory-installed check valves. Unfortunately, the original suction

and discharge check valves in these pumps utilized a metallic seat

ring and an elastomer ring on the valve. Eventually, Stellite
' <
-5~

overlaid parts v/ere employed to form metal- to-metal seats for

effective erosion resistant seals in the check valves in these

rather conventional reciprocating "mud pumps."

Pump erosion has taken place in Synthane's product gas-quench

system where the gasifier product gases are quenched with water to

cool the gas as well as to condense water and oils. Coal dust is carried

over from the hydrogasifier and thus circulated with the quench

water. The water is recirculated by means of cast-steel centrifugal

pumps. Excessive corrosion erosion was experienced [3] in the

pumps by exposure to this solids-laden acidic condensate. Pump

wear was minimized by overlaying all wetted parts of the pump with

type 304 stainless steel. In addition, pH control was accomplished

by injection of anhydrous ammonia into the stream.

Pumps with a Ni-hard casing have failed by erosion at ERDA's

Synthane pilot plant plant at Bruceton, PA. At least two different

pumps carrying char/slurry at ambient temperature suffered severe

erosion [4,5], Pump #1 eroded through after 1200 hours of service,

while pump #2 eroded-to-failure after 900 hours of service

600 hours of which were spent circulating water and 300 hours

char/slurry. Both of these Ni-hard cased pumps possessed a 28%

chromium- iron impeller. In a third, unrelated pump failure, a flare

knock-out drum pump moving an oily water/slurry solution suffered

erosion of its steel case and cast-iron wear parts [6], The device

had been in service 450 hours. The temperature of the slurry ranged

between 150° and200°P. The eroded wear rings were replaced and the

casing reinstalled. It was estimated that the steel casing had

experienced approximately 30% wear and the wear rings lost 0.100 inch.
II - I l '
- 6-

No mention was made in the OCR Materials and Component Fai lure

Report as to whether any significant erosion of the cast iron

impeller, steel shaft or shaft sleeve (containing 11-13% chromium)

had taken place.

It is not known whether these pumps were of the same basic

design as the centrifugal pumps that eroded in the ICT-Hygas plant.

It should be remembered though that the Synthane process experiences

erosive/corrosive environments similar to the Hygas process.

The Pittsburgh and Midway solvent-refined coal pilot plant at

Fort Lewis, Washington, employed Sier-Bath pumps for a liquid-solvent/

diatomaceous- earth slurry for filter precoating. Wtih the pumps

operating at 700°F, a pumping capacity of 150 to 200 gpm and speeds of

260 to 1300 rpm, the pumps failed [7]. Excessive wear was observed in

the shafts in the stuffing box area and pump body. It was later

determined that these pumps were unsuitable for the application [8]

due to severe erosion and seal leakage, all of the screw-type pumps

originally installed to handle diatomaceous-earth precoat material

were replaced with centrifugal and piston-type pumps.

Also at the Fort Lewis SRC pilot plant, some 30 pumps in the

filtration and fractionation areas of the plant experienced seal

failures [9, 10]. Wear of the seals was subsequently eliminated by

replacing carbon rotating washers with tungsten carbide washers,

substituting asbestos-based nonmetal lie parts for original equipment.

Teflon parts, installing 5-micron filters in central seal flush

system for all double-seal pumps, and installing cyclone separators

in the filter- flushing system for single-seal pumps. It was also
'

‘

-

'

.
- 7

-

suggested that separate seal-flush systems be installed on each

pump.

The Slurry recycle stripper bottoms pump at the SRC pilot plant

developed an erosion failure after only 13 days of continuous operation

[11.12]. A hole was eroded in the cast carfon steel casing just

downstream of the discharge line diversion baffle in the area of an

eddy current. The pump has a standard end- suction and centerline

discharge design with an enclosed cast-iron impeller with hardened-iron

wear rings. The pump operated at 3500 rpm with 21% efficiency and

a suction pressure of 50 psig. The pumping temperature was 750 °f

maximum and the pump had a capacity of 60 gpm. Not only was the casing

ring completely eroded, but the entire casing ring mounting was

eroded away. The suction nozzle was "coned" toward the impeller

volute, the nozzle being eroded quite thin next to the impeller.

It was estimated that approximately one quarter inch of metal was

eroded from the face of the cast carbon-steel casing. Wherever there

was an irregularity in the steel case, e.g., at a vent or drain hole,

significant erosion occurred. The pump was repaired by facing the

entire casing with Stellite. It was also recommended that certerline

discharge pumps be avoided in this portion of the plant. Better results

might be obtained by using a tangential discharge pump, where the

deflection baffle contained therein does not erode. It has also

been recommended for longer pump life that either the casing, impeller,

and wear ring material be made of HC-250 chromium base alloy (550 to

650 BUN) [12] or there be chrome plating of internal pump areas

coupled with a reduced pump speed [13].
'

-

.
' - 8 -

The slurry charge pump in the solid-liquid separation unit at the

Grand Forks, North Dakota, Project Lignite process demonstration unit

failed and had to be replaced [14,15]. This pump is a nine-stage auger

type pump with a steel rotor and viton stator. Erosion had increased

the clearance between rotor and stator till it was no longer possible

to obtain adequate discharge pressure for operation of the unit.

Valves

The leakage, wear, erosion and replacement of valving is often

I mistakenly considered as one of the less critical effects in the

technical operation of coal conversion plants, yet it has a major

effect on the economic operation. Few valve failures (which occur

principally through erosion degradation) are major in nature, even

fewer failures result in plant shutdowns, yet a special attention will

have to be given to the erosion resistance materials used in the

construction of these ubiquitous components. The liner of Incalloy

800 in a high temperature gate valve in the Hygas pilot plant was

severely eroded during operation [2]. The deterioration, believed to

have been caused by misalignment, manifested itself in a section of

more than three square inches on one side of the valve. Cause of the

erosion were 8x20 mesh dolomite solids entrained in a 1450°F recycle

gas moving with a velocity of 55 to 100 feet/second.

The importance of metal-to-metal seating surfaces in check valves

of high-pressure reciprocating pumps in the Hygas process was

discussed in the previous section. Suffice it only to restate here

the importance of erosion resistance in these components.

It might be pointed out that a very successful example of erosion
*

,

,

.

J I
-9-

control in the harsh coal gasification environment is the pressure

letdown through the char slurry valve [3]. In order to further

process the spent char from the hydrogasifier, the slurry must be

cooled and then reduced from operating pressure to atmospheric

pressure. This pressure reduction is accomplished at Hygas by use

of a variable-orifice slurry choke, which consists of two opposing

faces of tungsten carbide containing off-center holes. As the faces

are rotated, the holes overlap to create a passageway through which

the very erosive 25% solid slurry dissipates a pressure which may

range up to 1500 psi.

The Process Development Unit (PDU) of Project Lignite at the

University of North Dakota has experienced erosion failures in control

valves and safety valves [14,15]. The valve trim had been badly

eroded by coal slurry.

The hydrogenation PDU of USS Engineers and Consultants, Inc.,

Clean Coke process had leaks in residue letdown valves, apparently

the result of erosion from solids impingement on the seat body below

tungsten-carbide inserts, necessitating new valve seats having extended

tungsten-carbide inserts [16],

Wood and co-workers only very recently reported (see Oct. 1, 1976 [17]

issue of the ERDA Newsletter "Materials and Components in Fossil

Energy Applications") on valve abrasion/erosion experiences at the

stirred fixed-bed, low-BTU, gas pilot plant at ERDA's Morgantown Energy

Research Center. At this site, leaks through the coal feed, ash

discharge, and cyclone lock-hopper ball valves have forced shutdown

of the plant. These leaks have been the result of abrasive wear caused

from small coal and ash particles being trapped between mating surfaces
-

-

-
- 10 -

of balls and seats. Some of the more successful replacements for

valve seats have included Stellite- 3, Stellite-6, and 25% Cr-white iron

seats. With some 500 hours of service, these new seats show only slight

abrasion or corrosion. In the hot-product gas line, solid Stellite3

and Hastalloy-coated carbon-steel butterfly valves for pressure letdown

have eroded within 30 hours in the 1300°F (700°C) temperatures. Tungsten

carbide and Inconel-900 fixed orifices substituted for the valve

were more successful. Butterfly valves and machined valve body liners

made from Inconel-600 were also tested. Butterfly valves made from

Haynes-93 alloy were still in good condition after 40 hours service.

The Inconel liner, however, did fail. Cast hard-metal liners are

expected to yield more promising results.

The Laramie Energy Research Center's in-situ gasification

facility has not yet experienced erosion failures in its gas

withdrawal valves, but all the necessary conditions (lack of baffles

and cyclones to remove particulate matter at the wellhead) appear to be

present [18]

.

The early results of failure analyses [19,20] of a pressure

letdown valve trim- set from the Pittsburgh Energy Research Center's

(PERC) Synthoil plant indicates the preferential erosion that took

place may have been accelerated by geometric factors resulting

from a mechanical failure.

A good survey of the technology of corrosive-erosive wear

process and of the all-important letdown valve trim used in present

liquefaction pilot plants already exists [21]. The survey not only

reviews early experimental coal- liquefaction pilot processing endeavors

made in the United States but in Germany as well. The five
r
- 11 -

major process-development efforts currently underway in the U.S.

are discussed in detail, along with the designs of valve trim in

use, methods of throttling, procedures used to modify valves and

a variety of other wear problems present in coal liquefaction systems.

It would be redundant to report these data again in this survey;

the reader is referred to the appropriate references at the end of

this paper.

Transfer Lines (piping, elbows, crosses, etc.)

In the design of transfer lines one should make a judicious

choice for optimum velocity--high enough to prevent particle drag

but low enough to prevent excessive friction and damaging particle

impingement. Maximum erosive wear occurs in those components that

are exposed to the highest linear velocities. Where novel design

cannot accomplish proper erosion control, wear and erosion in

transfer lines can be minimized by the use of hard alloy liners

(e.g., type 410 stainless steel), wear plates, or application of

hard facing materials such as Ni-hard, the stellites or the colmonoys.

The use of elastomers for protection may be limited by chemical action

with the carriers as well as by temperature. For many process

components, the careful use of wear-resistant alloys (Fe-base,

Co-base, Ni-base) in the proper alloy condition, whether it be cast,

wrought, or some other condition, will lead to acceptable component

lifetimes. In suitably large diameter pipes, it has been desirable

to gun or cast a dense refractory bn pipe walls to avoid erosion.

One transfer component particularly susceptible to erosion is

the cross. The IGT-Hygas people found severe erosion in one of
r
- 12 -

their crosses transporting a slurry of canal water and waste char

from the slurry mixing vessel to the pressure let-down valves [12].

The 6000-pound, forged, socket-welded cross is made of ASTM alloy

A105. This eroded cross experienced slurry (approximately 10% char)

flows of 25 to 30 gpm at temperatures between 200 and 300°F and

a pressure of approximately 1000 psi (the cross was designed to handle

slurries with temperatures of 500°F and pressures of 1650

psi). Service life of the cross was thought to have been 4 to 5 years.

Actual operating hours of the IGT-Hygas cross is unknown, although

it was thought to have experienced approximately 100 thermal

cycles.

The introduction of 90° bends in pipes and pipe elbows makes the

locations susceptible to erosion. Documentation of an erosive failure

in the ERDA Synthane Bruceton plant includes that on elbows [23] . A

standard elbow in a four-inch line conveying steam with coal fines

from the plant's char cooler eroded through after a service life

of approximately one week. The elbow material was an A2A alloy. The

elbow was repaired by welding on a reinforcement pad.

A 90° bend in the same plant's coal slurry transport line made

it a suspect for erosion failure [24]. A timely change in operational

parameters (changing slurry medium and reducing flow rate) has reduced

the potential for erosion.

Erosive failures in elbows were experienced at the in-situ

gasification facility of the Laramie Energy Research Center [18].

These elbows failed from the impact of large-size particulates exiting

from the production well. The particulate size (sometimes up to one
-

»

I

'

.
-13-

inch) as well as volume fraction increase dramatically near the end

of an underground burn to the Hanna coal seam. Visible dents were

evident in the pipe elbows and orifice plates. Where sufficient

path length was available before entering an elbow, the large

particles were able to obtain a high, damaging velocity (the exiting

hot, particle-laden gas traveled at a velocity of 800 feet/sec. with a

temperature of 450 to 600°F) . It is therefore advisable to avoid

long lengths of straight pipe. Baffling the exiting gas and/or the

introduction of cyclones (both of which were not present) should

materially reduce erosion in the pipe elbows. Instead of changing

direction with elbows, substitute right angle tees so that particulates

will collect in the pocket and form a wear surface according to flow lines.

By placing elbows close together and/or near valves metal wastage

should be minimized. As a future consideration, more wear-resistant

elbow materials may be employed at the plant rather than using

’’available materials”

Manual welding of pipe in the field and the use of chill rings

inside the pipe will result in localized erosion of the pipe adjacent

to the ring [18]. Although such chill rings are ncessary for

alignment and aid in welding, they do represent an internal obstruction,

intercepting particulates and producing local erosion. Automatic

welding processes and appropriate rigging can eliminate their need.

In Consol's CCb Acceptor lignite coal gasification pilot plant,

the pipe serving as a flue gas outlet in their Belmas regenerator had

been extensively thinned because of erosion [25]. Failure was

accelerated by a process upset, where an abnormally high level of
I

'

'
-14-

carbon monoxide was generated. The afterburning of the CO caused

very high temperatures and a gas/mctal reaction. Before the process

upset, the pipe outlet had been in service for 13,000 hours, carrying

an 1830°F flue gas with M2 S , CO, and S in the ppm range.

Erosion was only one of the processes contributing to the

deterioration of a carbon steel pipe carrying coal tar liquid at a

180°F temperature [26]. The one- inch schedule 40 line was replaced

with a socket-welded 316- stainless steel pipe (schedule 80). Since

the failure was in the threaded zone, corrosion and vibration were also

suspected of being at fault although no detailed laboratory study

was made of the failure.

Preliminary investigations indicate that erosion may have

caused perforation and failure of the main gasifier transfer line

bellows at the IGT-Hygas plant [27, 28, 29] . A localized failure

in a liner tube caused erosion on the interior surface of the bellows.

With perforation of this interior surface, subsequent erosion of the

exterior bellows surface took place. Although the tube serving as

the lining within the bellows had not yet been examined, laboratory

investigations of the failed bellows seem to indicate particle

impingement and consequential erosion of the metal.

Stainless steel (type 316) tubing that makes up the preheater

coils in the process development unit of Project Lignite at the

University of North Dakota has failed, and several of these failures

were thought to be due to erosion [30]. At the' same time, evidence

[20, 31, 32] of chloride stress-corrosion cracking was plaguing the
)
-15-

operation and may also have played an important, if not dominant,

role in the failures.

Misalignment in an expansion joint caused severe erosion to

occur in a 4-inch lift line at the Consol CO2 Acceptor Lignite coal

gasification pilot plant [33], Although the materials were type 310

.stainless steel inlayed with Stellite #12 rod, holes were eroded in

the inner liner and in the reducing cone after 630 hours of service.

These expansion joints are located in a 4-inch transfer line which

pneumatically carries dolomite from the gasifier to the regenerator

vessel. The entrained dolomite is 8x20 mesh. Recycle gas (composed

of CO, CO2 , N2 and S in the ppm range) at 1450°F moves the dolomite

with a velocity of 55 feet/sec. The expansion joint had a long

history of repeated erosion failures. It has undergone redesign

to minimize the angle of impingement of the solids. The velocity

of the carrier gas wr as reduced along with coating the expansion joint

area with Stellite. Aside from erosion due to local turbulence or

directed impingement, the transfer line is subjected to a corrosive

gas which may be abetting the wear process.

Cyclones

This equipment, when properly lined with wear-resistant metals

or refractories, suffers few erosion failures. When a cyclone is

found to be unlined, e.g., the Raymond cyclone separator at the CO2 Acceptor pilot plant. in Rapid City, South Dakota, abrasion-resistant

0 linings are recommended [34].
,
- 16-

The outlet nozzle of the cyclone is the most erosion-prone

component, and it is generally treated as an expendable item by

plant operators.

The IGT-Hygas plant has experienced erosive damage to the bottom

Grayloc flange on one of its cyclones [35].

Hydrocyclones used in coal- liquefaction processes experience

considerably greater abrasion erosion. Cemented carbides or Ni-hard

stainless steel are often used to ameliorate the erosion problem.

In those very large hydrocyclones that experience erosion, it

may be well advised to apply a hard chromium plating to the affected

areas rather than to the whole chamber.

Regenerators

The importance of having erosion-resistant refractories lining

opposite inlet lines in regenerators is demostrated in a failure

experienced at the CO2 Acceptor Pilot Plant [36]. Hot air, hot

makeup gas, char, and dolomite entering the regenerator eroded a

hole, directly opposite and in line with the inlet, through the

refractory and insulation (7 inches of Johns-Manville Superex

next to the shell, 3 inches of A. P. Green's VSL-50 insulating

castable as an inner layer) . The regenerator was subsequently

relined with 10 inches of insulating castable next to the vessel

shell. In addition, the bottom 10 feet of the regenerator and bottom

head will also have 3 inches of a phosphate-bonded alumina outer

layer (for severe erosion conditions) . The upper portion of the

vessel and top head will have 3 inches of a refractory for moderate

erosion resistance (one containing a high-purity calcium aluminate

cement)

.

- 17 -

Comprcssors

Erosion damage (stuffing-box packing and scored piston rings)

in a piston-type compressor has caused hydrogen gas leaks in the

hydrogenation PDU of USS's Clean Coke process [16]. Another compressor

was used to complete the coal-hydrogenation run.

Other Components

Although a number of components were not mentioned above, this

is not to be taken as an indication that they are erosion free. Operating experience for many of the gasification/liquefaction processes

has been all too brief and intermittent. With continued operation

(and accompanying process upsets) more failures will be reported.

Many components are considered, if not designed, to be inexpensive,

expendable, and locatable for ease of repair or replacement. In time,

with the development of more erosion-resistant materials, even the

status of these will change.

Components that also must be considered susceptible to erosion

are gasifier internals -- those transfer lines connecting the various

stages within gasifiers. Erosion will be compounded by the very

corrosive atmospheres present in these devices.

All sorts of joints--be they slip, expansion, flanged, welded,

etc. --will result in erosion whenever misaligned, particularly if

they contain a liner.

Lock hoppers (either feed or char) will be subjected to

extensive sliding wear.

Waste heat boilers will invite erosion at the inlet side where

turbulence occurs. For that matter, all turbulence caused by the
'
-18-

introduction of high velocity fluids into chambers will be a source

of localized erosion unless designed with appropriate caution

(judicious use of wear plates, etc.).

The fly ash impingement and erosion of turbine blades at the

far end of the conversion plant need only be remembered here, as much

has been said and written already about this critical problem area.

It is obvious from the above-mentioned failures that more

regard will have to be given to erosive wear in coal conversion plants.

New, improved materials will have to be developed to meet the operating

requirements of these plants. Existing specialty alloys will have

to be used in the fabrication of entire components and in other

cases, wear plates, inserts, liners, overlays, and inlays of

hardened alloys and ceramics must be employed. Until the mechanisms

of erosion and accompanying environmental effects (whether they be

deleterious or otherwise) are better understood, the highly empirical

approaches presently used will still have to be followed in solving

the current erosion problems.

Acknowl edgment

This work was funded in part by ERDA-Fossil Energy under

contract number E(49-l)- 3800.
„ - ' , '
-19-

References

[1] Smith, I. H. , and Werner, G. J., Coal Conversi on Technology , (Noyes Data Corporation, Park Ridge, New Jersey, 1976).

[2] Schorr, J. R. , editor, ERDA Material and Component Newsletter,

Sept. 20, 1975.

[3] Youngblut, K. , "Experience with Materials in Hygas Coal

Gasification Plant," NACE Conference on Corrosion, Anaheim,

CA, 1973.

[4] Peloquin, M. , ERDA Materials and Components Failure Report,

Oct. 3, 1975.

[5] Jackson, R. , ERDA Materials and Components Failure Report,

Mar. 11, 1976.

[6] Jackson, R. , ERDA Materials and Components Failure Report,

Mar. 19, 1976.

[7] Anonymous, ERDA Fossil Energy Advisory Report No, 13, Mar. 26, 1975.

[8] Greenlee, N. , Solvent Refined Coal Plant, to Fisher, C., Office

of Coal Research, Jan, 27, 1975.

[9] Danhof, A., to Samuels, L. , Solvent Refined Coal Plant, Interoffice

Report, Dec. 20, 1974.

[10] Samuels, L. , to Chenoweth, G. , Solvent Refined Coal Plant, Interoffice Report, Apr. 15, 1975.

[11] Frankel, H. E. , Private Communication,

[12] Danhof, A., to Samuels, L. , Solvent Refined Coal Plant, Interoffice

Report, Aug. 13, 1975.

[13] Williamson, F., to Frankel, H. , ERDA Newsletter, Oct. 1, 1976.

[14] Severson, D. , University of North Dakota, Project Lignite Monthly

Technical Progress Report, No. 39, ERDA Contract E(49-18) -1224,

June 1975.

[15] Severson, D. , University of North Dakota, Project Lignite Monthly

Technical Progress Report, No. 44, ERDA Contract E (49- 18) - 1224

,

Nov. 1975.

USS Engineers and Consultants, Inc., Monthly Report for July 1976,

ERDA Contract No. E(49-1S) -1220, Document No. FE-1220-16, Aug. 1976.

[ 16 ]

I - 20-

[17] Schorr, J. R. , editor, ERDA Material and Component Newsletter,

Oct. 1, 1976.

[18] West, A,, Sandia Laboratory, to Frankel, H. , ERDA, Correspondence,

Aug. 10, 1976.

[19] Canonico, D., and Edmonds, D. , Oak Ridge National Laboratory,

Project Report, July 1975,

[20] Martin, W. , Oak Ridge National Laboratory, Quarterly Progress

Report, May 18, 1976.

[21] Battelle, Columbus, Ohio, "A Review of Letdown Valve Experience

in Coal Liquefaction Service, n a Survey to the Electric Power

Research Institute, Palo Alto, CA, Dec. 15, 1975.

[22] Stanton, G. C., Argonne National Laboratory, to Reiman, K. J.,

Intra-Laboratory Memo, Sept, 30, 1975.

[23] Jewell, J., ERDA Materials and Components Failure Report,

July 21, 1976.

[24] Stanton, G. C. , Argonne National Laboratory, to Reiman, K, J.,

Memo, Mar. 19, 1976.

[25] Schulz, C., ERDA Materials and Components Failure Report,

June 28, 1976.

[26] Vandergrift, E. , ERDA Materials and Components Failure Report,

Sept. 9, 1976.

[27] Greenberg, S,, Argonne National Laboratory, to Orchard, B.

,

Institute of Gas Technology, Telecommunication ? May 5, 1976.

[28] Weeks, R. , Argonne National Laboratory Quarterly Report, Dec. 1975.

[29] Weeks, R., Argonne National Laboratory Quarterly Report, Mar. 1976.

[30] Anonymous, Project Lignite PDU Report, University of North Dakota.

[31] Barney, W., to Staff, Memo, July 24, 1975.

[32] Anonymous, Minutes of the Project Lignite Advisory Committee

Meeting, University of North Dakota, July 10, 1975.

[33] Schulz, C., ERDA Materials and Components Failure Report, Apr. 3,

1975.

[34] Anonymous, Project Advisors Meeting C0^ Pilot Plant, May 21, 1974.
,

.

X
[35] Orchard, W. P., Institute of Gas Technology, to Elli.ngson, W. A.

Argonne National Laboratory, Correspondence, Jan. 7, 1976.

[36] Edwards, D. , and Garroutte, J. , to Fink, C. , Consol Failure

Analysis Report, Dec. 12, 1976.