Res

ult

s o

f a F

eas

ibilit

y a

nd

Pre

lim

inary

En

gin

eeri

ng

Stu

dy f

or

a S

yste

m t

o P

rocess a

nd

Sta

bil

ize S

cru

bb

er

Wa

ste

fro

m t

he A

PS

Fo

ur

Co

rners

Un

it 4

an

d 5

FG

D

Sys

tem

s

Pap

er

#155

Go

rdo

n M

aller,

Jo

hn

Mit

ch

ell

– U

RS

Co

rpo

rati

on

Pro

cess T

ech

no

log

y

Off

ice, A

usti

n,

Texas

2013

Wo

rld

of

Co

al A

sh (

WO

CA

) C

on

fere

nce

- A

pri

l 22-

25, 2

013

in L

exin

gto

n, K

Yh

ttp

://w

ww

.fly

ash

.info

/

Pro

ject B

ackgro

und

– F

CP

P 4

an

d 5

2

x 7

90 M

W u

nits

U

nits c

onstr

ucte

d in 1

960’s

1

98

4 -

WF

GD

an

d F

F a

dded

–S

cru

bb

er

slu

dg

e th

icke

ne

d a

nd

filt

ere

d

–F

ilte

r ca

ke

ble

nd

ed

with

ash

an

d

tru

cke

d to

offsite

min

e fo

r u

se

as m

ine

ba

ckfill

2

00

4 –

Sto

p o

ffsite m

ine b

ackfill

–T

hic

kene

d s

cru

bber

slu

dg

e s

ent to

lin

ed

imp

ou

nd

me

nt

–F

ly a

sh

se

nt to

dry

la

nd

fill

–P

ort

ion

of a

sh

so

ld

Pro

ject B

ackgro

un

d (

cont.

)

2

01

2:

–L

ined im

poun

dm

ent

nearly f

ull.

C

annot

be

exp

an

de

d

–P

roposed C

CR

rule

s e

xpecte

d t

o e

ncoura

ge d

ry

rath

er

than w

et sto

rage o

f C

CR

’s

–O

rig

ina

l scru

bb

er

wa

ste

pro

ce

ssin

g e

qu

ipm

en

t in

questionable

shape (

VD

F in b

ad s

hape)

–U

RS

begin

s e

ngin

eering s

tudy to identify

and

eva

lua

te b

est

op

tio

ns f

or

CC

R d

isp

osa

l

FG

D T

hic

kener

Ash

Silo

s a

nd

Wa

ste

Pro

ce

ssin

g

Build

ing

Wa

ste

Pro

ce

ssin

g B

len

din

g E

qu

ipm

en

t

(pu

g m

ill m

ixe

rs)

Lin

ed Im

poundm

ent

Dry

Landfill

Conta

inin

g A

sh

Desig

n F

easib

ility

Analy

sis

Big

Pic

ture

Obje

ctive –

Can s

cru

bber

slu

dge

and

ash

be b

lend

ed

to

pro

duce

a m

ate

ria

l

that

is s

tab

le a

nd s

uitab

le f

or

pla

ce

me

nt in

dry

la

nd

fill?

Is T

here

Enough A

sh?

C

oa

l b

ein

g f

ire

d:

–L

ow

sulfur

sub-b

itum

inous

–S

ulfur

conte

nt

– 0

.6 t

o 1

.0%

–A

sh

co

nte

nt – 1

7 t

o 2

3%

M

ate

ria

l ba

lance (

pro

du

ctio

n r

ate

s, lb

/hr)

:

–F

ly a

sh –

311

,656

–S

cru

bber

solid

s (

90%

rem

oval) –

46,6

44

–T

hic

kener

und

erf

low

slu

rry (

36 w

t.%

solid

s)

– 1

29,5

69

Are

Pro

pert

ies o

f S

cru

bber

Solid

s S

uitable

for

Ble

ndin

g?

P

SD

ana

lysis

, se

ttlin

g t

ests

and

filt

ratio

n t

ests

su

gg

est

tha

t F

GD

solid

s h

ave r

ela

tively

good s

ettlin

g p

ropert

ies

for

mg

-lim

e p

roce

ss

O

pe

ration o

f th

ickener

at hig

her

solid

s c

oncentr

ation

(>3

6 w

t. %

) is

possib

le w

ith low

cost upgra

de o

f

thic

kener

contr

ols

40

.0

45

.0

50

.0

55

.0

60

.0

65

.0

20

30

40

50

60

70

Cake Solids Conc., Wt.%

Dry

Tim

e p

er

Un

it C

ake

We

igh

t, s

ec/

lb/f

t2

Cak

e S

olid

s as

a F

un

ctio

n o

f M

ixtu

re a

nd

Dry

Tim

e p

er

Un

it C

ake

We

igh

t

29

% F

eed

So

lids

45

% F

eed

So

lids

36

% F

eed

So

lids

What

is O

ptim

um

Mix

ture

?

Sam

ple

IDCo

mpo

nent

sD

escr

ipti

on

78-3

6-4

(bef

ore:

72-

33-6

)

Thic

kene

r Und

erfl

ow

Slur

ry, F

ly A

sh, a

nd L

ime

78w

t% S

olid

s in

Fin

al S

ampl

e. M

ix to

tal c

ompo

siti

on:

34.

6% =

Thi

cken

er U

nder

flow

Slu

rry

(36.

4wt%

sol

ids

in th

e sl

urry

)

61

.4%

= F

ly A

sh

4

.0%

= L

ime

78-3

6-2

(bef

ore:

72-

33-3

)

Thic

kene

r Und

erfl

ow

Slur

ry, F

ly A

sh, a

nd L

ime

78w

t% S

olid

s in

Fin

al S

ampl

e. M

ix to

tal c

ompo

siti

on:

34

.6%

= T

hick

ener

Und

erfl

ow S

lurr

y (3

6.4w

t% s

olid

s in

the

slur

ry)

63

.4%

= F

ly A

sh

2

.0%

= L

ime

78-3

6-0

(bef

ore:

75-

33-0

)

Thic

kene

r Und

erfl

ow S

lurr

y

and

Fly

Ash

78w

t% S

olid

s in

Fin

al S

ampl

e. M

ix to

tal c

ompo

siti

on:

34

.6%

= T

hick

ener

Und

erfl

ow S

lurr

y (3

6.4w

t% s

olid

s in

the

slur

ry)

65

.4%

= F

ly A

sh

0

% =

Lim

e

Is B

len

de

d M

ate

ria

l S

uita

ble

fo

r

Pla

ce

me

nt in

La

ndfill?

T

ests

Pe

rfo

rme

d:

–P

enetr

om

ete

r

–P

ain

t filter

–A

tte

rbe

rg lim

its (

pla

sticity)

–U

nconfined c

om

pre

ssiv

e

str

ength

–T

ri-a

xia

l sh

ea

r str

ess

–H

ydra

ulic

con

ductivity /

perm

eabili

ty

Geote

chnic

al T

est

Results

Conclu

sio

n:

Lim

e a

dd

itio

n is n

ot

req

uire

d t

o o

bta

in m

ate

ria

l su

ita

ble

fo

r la

nd

fill.

D

en

sity a

nd

str

ength

for

the s

am

ple

without

lime a

re h

igher

than e

xis

ting fly

ash m

ate

rials

pla

ced in landfill

Ca

n P

lan

t C

on

tinue

to S

ell

Fly

Ash?

E

stim

ate

d a

nnu

al fly a

sh p

rod

uctio

n f

or

Unit 4

an

d 5

is a

bo

ut

1.2

3 m

illio

n t

on

s

P

lant

desire

s to

sell

300

K to

ns p

er

yea

r

30

0K

ton

s w

ort

h $

1.8

75 m

illio

n a

t $

6.2

5 p

er

ton

F

ly a

sh a

vaila

ble

fo

r sale

aft

er

po

rtio

n u

sed

fo

r

ble

ndin

g:

–T

hic

ke

ne

r u

nd

erf

low

= 3

0 w

t.%

: 1

91

K t

on

s

–T

hic

kener

und

erf

low

= 3

6 w

t.%

: 553K

tons

PR

EL

IMIN

AR

Y E

NG

INE

ER

ING

Conceptu

al D

esig

n

D

esig

n a

ssum

ptio

ns f

or

op

era

tion:

–C

CR

wa

ste

to

be

pla

ce

d in

la

nd

fill

will

be

a m

ixtu

re o

f th

icke

ne

d

scru

bber

slu

rry fro

m thic

kener

and

fly a

sh

to

ob

tain

a s

olid

s

co

nce

ntr

atio

n o

f 7

5 w

t.%

to

78

wt.

%

–T

hic

ke

ne

r o

pe

rate

d to

ob

tain

an

underf

low

solid

s c

oncentr

ation o

f 36

wt.

%

–T

hic

ke

ne

d s

cru

bb

er

slu

rry a

nd

fly

ash

will

be

mix

ed

in

a p

ug

mill

mix

er

–N

o lim

e a

dditio

n to m

ixed w

aste

Desig

n O

bje

ctives for

New

Waste

Syste

m

M

axim

ize r

euse o

f exis

tin

g e

quip

men

t to

kee

p

ca

pita

l co

sts

as lo

w a

s p

ossib

le

D

esig

n a

syste

m th

at is

ea

sy to

op

era

te,

relia

ble

an

d c

ap

ab

le o

f pro

ducin

g a

co

nsis

tent w

aste

ma

teria

l

P

rodu

ce a

waste

ma

teria

l th

at is

accep

table

fo

r

dis

po

sal in

a d

ry la

nd

fill

and

whic

h c

an

be e

asily

ha

nd

led a

nd t

ranspo

rte

d w

ith

lo

w r

isk fo

r d

ustin

g

an

d s

pill

age

A

vo

id e

xpe

nse o

f lim

e a

dditio

n

De

tails

of P

relim

ina

ry E

ngin

ee

ring

De

sig

n

5

0%

of

exis

tin

g 6

” F

RP

tra

nsfe

r p

ipin

g r

eu

se

d,

50

% r

ep

lace

d

T

hic

ken

er,

TU

T s

ludg

e tan

k a

nd

pu

g m

ill m

ixers

refu

rbis

he

d

an

d u

pgra

de

d

A

ll pu

mps e

xcep

t th

icken

er

un

de

rflo

w p

um

ps r

ep

laced

N

ew

man

ifo

ld d

esig

n r

equ

ire

d t

o d

ire

ct slu

rry f

rom

eith

er

thic

ken

er

to a

ny o

f th

ree

pu

g m

ill m

ixers

N

ew

in

str

um

en

ts a

nd c

on

tro

ls

Pro

cess F

low

Dia

gra

m

Pug

Mill

Up

gra

de D

esig

n D

eta

ils

M

od

ific

atio

ns to

pu

g m

ills:

–S

lurr

y d

istr

ibu

tion h

eader

–M

ixin

g c

urt

ain

dow

nstr

eam

of

feed c

hute

–C

urr

ent w

ate

r header

to b

e u

sed a

s w

ash h

eader

Pu

g m

ill M

an

ifo

ld (

Sh

ee

t 1

)

Pug m

ill M

anifold

(S

heet

2)

Tota

l P

roje

ct

Capital C

osts

De

scri

pti

on

To

tal

Co

st

Tota

l E

ngin

eering S

erv

ices

$943,5

00

Tota

l D

irect

Pro

cure

ment

$1,4

36,6

80

Tota

l C

onstr

uction M

anagem

ent

Serv

ices

$388,5

00

Tota

l C

onstr

uction

$2,2

17,8

36

Pro

ject

Contingency (

15%

)$705,5

17

Tota

l E

PC

CM

Pro

ject

Cost

$5,6

92,0

33

UR

S

5-J

un

-12

Fo

ur

Co

rners

Slu

dg

e P

roje

ct

UR

S P

roje

ct

Nu

mb

er

23446139

Co

mp

ariso

n o

f A

ltern

ative T

echnolo

gie

s

Ble

ndin

g s

yste

m a

s d

esig

ned

$5.7

MM

Ble

ndin

g s

yste

m a

s d

esig

ned w

ith

new

pug m

ill m

ixers

$6.8

MM

New

250 a

cre

double

-lin

ed a

sh p

ond

with leak d

ete

ction

$60 -

$70 M

M

ZLD

syste

m*

$85 –

95 M

M

*Assum

es s

cru

bber

solid

s a

re d

ew

ate

red a

nd Z

LD

technolo

gy (

phys-c

hem

tre

atm

ent, R

O-b

rin

e c

on

ce

ntr

ato

r, c

rysta

llize

r) u

se

d to

tre

at liq

uid

dis

ch

arg

e.

Stu

dy C

onclu

sio

ns

B

lend

ing o

f th

icke

ne

d s

cru

bbe

r slu

dg

e a

nd

fly

ash a

t a

so

lids c

oncentr

ation o

f 75 w

t.%

to 7

8 w

t.%

will

pro

duce a

ma

terial th

at is

accepta

ble

for

pla

cem

ent

in a

dry

landfill.

Th

e m

ate

rial w

ill a

ctu

ally

have s

uperior

geote

chnic

al

pro

pert

ies t

han m

ate

rial curr

ently b

ein

g p

laced in landfill

U

se o

f lim

e t

o s

tabili

ze t

he w

aste

mate

rial is

not

ne

cessary

T

he p

roposed s

yste

m m

akes m

axim

um

reuse o

f exis

ting

pla

nt

equip

ment

O

pe

ration o

f th

e n

ew

syste

m s

hould

be e

asy a

nd r

elia

ble

an

d p

roduce a

waste

mate

rial w

ith c

onsis

tent

physic

al

an

d c

hem

ical pro

pert

ies

Stu

dy C

onclu

sio

ns (

continued

)

P

lan

t can c

ontinu

e t

o s

ell

fly a

sh a

t curr

ent le

vels

.

Desig

n o

pera

tion

will

allo

w a

sh s

ale

s t

o incre

ase t

o 5

53K

ton

s p

er

ye

ar

T

he p

roposed m

odific

ations t

o e

quip

ment

will

im

pro

ve

mix

ing a

nd s

ignific

antly r

educe d

usting a

nd s

pill

age

du

ring h

andlin

g a

nd t

ransport

T

he d

ischarg

e o

f liq

uid

purg

e w

ate

r fr

om

the F

GD

syste

m in t

he w

aste

will

be m

ore

than s

uff

icie

nt to

allo

w

the

pla

nt

to o

pera

te a

s Z

LD

–1

67

gp

m; 2

39

,78

3 g

pd

Gord

on M

alle

r –

UR

S C

orp

ora

tion P

rocess

Te

ch

no

log

y O

ffic

e, A

ustin

, T

X

go

rdo

n.m

alle

r@urs

.co

m