Lehigh UniversityLehigh Preserve

Theses and Dissertations

1973

Removal of suspended and dissolved solids fromprocess water-computer simulationThomas J. KopecLehigh University

Follow this and additional works at: https://preserve.lehigh.edu/etd

Part of the Chemical Engineering Commons

This Thesis is brought to you for free and open access by Lehigh Preserve. It has been accepted for inclusion in Theses and Dissertations by anauthorized administrator of Lehigh Preserve. For more information, please contact preserve@lehigh.edu.

Recommended CitationKopec, Thomas J., "Removal of suspended and dissolved solids from process water-computer simulation" (1973). Theses andDissertations. 5104.https://preserve.lehigh.edu/etd/5104

.: .. _<,',_,_ ..... \ •.

REMOVAL OF SUSPENDED AND DISSOLVED SOLIDS FOOM PROCESS WATER-COMPUTER SIMULATION

by

Thomas J. Kopec

A Research Report

Presented to the Graduate Faculty

of Lehigh University

in Candidacy for the Degree of

Master of Science

in

Chemical Engineering

Lehigh University

Bethlehem, Pa.

May, 1973

CERTIFICATE OF APPROVAL

This research report is accepted and approved in partial ful­fillment of the requirements for the degree of Master of Science in Chemical Engineering.

l!~~ (dat

ii

Dr. Curtis Clump Professor in Charg

Dr. Leonard Wenzel Chairman of the Department of Chemical Engineering

. \

ACKNOWLEIXiEMENTS

I would like to thank Dr. Curtis W. Clump for his supervision

and guidance during the course of this project. My thanks also go

to Dr. Alan S. Foust for his help in setting up the Bureau of Mines

program.

The author is also grateful to Dan Kwasnoski and George Haines

of the Bethlehem Steel Corp. for their time and effort in obtaining

data for the gas scrubbing operation at the Bethlehem Steel plant.

Thanks also go to Frank W. Koko and Richard Greene for their know­

ledge and assistance in developing Program SOIJDS.

I would also like to express my grateful appreciation to the

Proctor and Gamble Co. for providing my financial support for my

graduate study.

iii

1 '·

i, ,,

TABLE OF CONTENTS

LIST OF FIGURES • • • • • • • • • • • • • • • • • • • •

LIST OF TABLES • • • • • • • • • • • • • • • • • • • •

ABSTRACT • • • • • • • • • • • • • • • • • • • • • • •

INTRODUCTION . . . . . . . . . . . . . . . . .. . . . . MODELING CONCEPTS I I I I I I I I I • I I I I I I I I I

PROCE3S DE3CRIPTI0N • • • • • • • • • • • • • • • • • •

DESIGN MODEL - PROGRAM SO LIDS • • • • • • • • • • • • •

ECO:OOMICS OF DESIGNED SYSTEM • • • • • • • • • • • • •

CASE STUDY . . . . . . . . . . . . . . . . . . . .. . .

V

V

1

3

6

7

15

18

21

RESULTS AND DISCUSSION • • • • • • • • • • • • • • • • 27

CONCLUSIONS AND RECOMMENDATIONS • • o • • • • • • • • • 29

APPENDIX • • • • • • • • • • • • • • • • • • • • • • • 31

RE:FER.ENCE3 • • • • • • • • • • • • , , , • • , • , , , 3 2

VITA • • • • • • • • • • • • • • • • • • • • • • • • • 34

iv

,,

'

f >"

'"

1

2

3

No, -l

2

3

4

LIST OF FIGURES

Removal of Suspended and Dissolved Solids from Process Water • • • • •• o ••••••

Capital Cost Versus Flow Rate Into Gas Scrubber •••••••••••••• • • • •

Operating Cost Versus Flow Rate Into Gas Scrubber •••••••••••

LIST OF TABLES

• • • • •

Equipment List • • • • • .. • • • • • • • • • •

Data Obtained From Bethlehem Steel . . . .. . . Build Up Rates For Dissolvable Solids

Economics For The Process ••••••

V

• •

• •

• • •

• • •

8

25

26

9

11

13

24

'I I l

l 1

I 1 1

l

l 1 1 1

ABSTRACT

The removal of dissolved solids from process water is a prob­

lem which is facing the Bethlehem Steel Corp. today. The State of

Pennsylvania has set standards for the discharge of industrial

effluents. Bethlehem Steel cannot handle the removal of dissolved

solids from the bleed stream from their gas scrubbing system to meet

these standards with existing equipment.

A system was designed to remove the dissolved ions found pre­

sent in this bleed stream. A fixed bed Ion Exchange system was the

technology used. The calculations were done by developing a computer

program to do the energy and material balances, size and cost the

equipment and calculate the utilities needed. The economic analysis

was done by a computer program developed by the Bureau of Mines. The

·program calculated the capital and operating costs for the process.

A study was made with the two computer programs. The water

flow into the gas scrubber was varied from 12,000 gallons per minute

to 8,000 gallons per minute. The programs were also run with the

dissolvable solids in the gas stream entering the scrubber set at

2.0 lbs. per minute and 10.0 lbs. per minute. The results show a

slight decrease in capital and operating costs as the water flow to

the scrubber is decreased. This is true for both dissolvable solids

rates. The capit~l and operating costs did drop appreciably for the

drop in disaolvable solids rates. The capital cost went from $3.3

1

million to $2.0 million. The operating cost was reduced from $1.6

million to $0.7 million. It was estimated that the capital costs

were within 30 per cent of the actual cost.

2

' .

J

INTRODUCTION

At present time, the Bethlehem Steel Corp. has five blast fur­

naces in operation at Bethlehem, Pa. They produce a source of air

pollution in the form of solid particulate carried out of the top of

eac.h furnace by hot flue gas. The solid particulate can vary in com­

position depending on the type of ore that is charged to the furnaces,

but will normally containSi02, Al2o3, Na2o, CaO, MgO, CaCl, Fa) and

Fe203.

Bethlehem Steel Corp. has in operation at this time a system to

remove this solid particulate from the gas. The dirty gas is first

passed from the furnace through a collection system to remove large

particles. The size of the particles in the gas leaving this system

will be 800 microns or less. The dirty gas is then passed through a

venturi scrubber to remove almost all of the solid particulate. The

gas is sent to another scrubbing system to remove the remaining amount

of particulate and then is burned as a low Btu fuel.

· Water is used as the fluid in the venturi scrubber to wash out

the particulate. Some of the particulate such as FeO and Fe203 have

essentially very little solubility in water. These solids will be

suspended in the water. Some of the solids such as Na2o and CaCl

will dissolve in the water. The water is treated and then recycled

back to the scrubber for reuse.

3

' ' . i I .

I I I

1

I I I I I J

'

l l J

l l

I

The treatment of the water consists of two operations: (1)

removal of suspended solids; (2) removal of dissolved solids. The

removal of the suspended solids is accomplished by the use of a

clarifier and a filter. However, a problem exists with the dissolved

solids. They begin to build up in concentration ap the water is re­

cycled. The present solution is to bleed some of the recycled water,

which has a dissolved solids concentration of 2500 ppm, to the river

and add fresh river water. This lowers the dissolved solids concen­

tration in the recycle stream.

Pennsylvania has laws governing the discharge of industrial ef­

fluents into waterways, regarding the dissolved and suspended solids

concentration of the effluent. A maximum limit of 500 ppm was set

for dissolved solids and 200 ppm for suspended solids. The limit set

for the suspended solids can be met with existing equipment. A new

system is needed for the removal of the dissolved solids.

The most feasible approach, at the present, to the problem of

the removal of dissolved solids has been by the use of ion exchange

technology. Other methods may be applicable to this industrial

problem, but must be proven to be economically competitive as the

ion exchange process. One factor to the key to making ion exchange

economically attractive is the regeneration of the resin. An inex­

pensiv~ regenerant and its recovery are the most important factors,

assuming that a suitable resin can be found to handle the stream

needed to be cleaned up.

4

A computer model, called SOLIDS, was developed to size and

cost the equipment need for the ion exchange process. The process

consists of the gas scrubbing and removal of the suspended and dis­

solved solids (see Figure 1). The model also calculates the required

utilities and raw materials and their costs. The capital and oper­

ating costs for the process were calculated by another computer,

which was developed by the Bureau of Mines• College Park process

evaluation group.

Bethlehem Steel Corp. supplied data from the actual gas scrub­

bing operation. This data can be found in Table 2. Data that was

needed, but was not obtained was the chemical analysis of particulate

in the gas stream entering the gas scrubber. This makes the rate of

dissolvable solids in the gas stream an unknown. This rate is needed

to design the ion exchange system.

5

,i \ !

MODELING CONCEPTS

Today computer models are becoming more feasible to design

chemical processes. With simulation models, many process studies

can be made in a short period of time. These models can become

large in physical size, so the programmer should be aware of how

to develop the model. The model should have a definite structure

and adequate documentation so a user could follow the logic involved.

All major variables should be read into the model and not set in the

program. The model should be capable of printing all process condi­

tions calculated.

The saving of computer time and core are also very important.

Overlays can be used to save computer core by writing over calcula­

tions done previously. Simulation models should have generalized

calculations. A system could be developed which could design every

pump in the design. A generalized mass and energy balance package

is needed, but is difficult to develop.

6

i! ,I

. ~ i l

., ~

I l

PROCESS DESCRIPTION

The process (see Figure 1) designed removes suspended and d s­

solved solids from the water from the gas scrubber. The treatment

of this water takes place in two sections: (1) suspended solids

removal} (2) dissolved solids removal.

The suspended solids section consists of a clarifier and a

filter. The underflow of the clarifier, containing the settled

solids, is sent to a rotary drum filter for final separation of the

solids. These solids are stored and reused later as part of the

feed to the blast furnaces. The overflow of the clarifier is split

into two streams. Most of it is recycled back to the scrubber feed

tank and the rest is sent to the dissolved solids section for clean

up.

The dissolved solids section makes use of a fixed bed ion ex­

change system. The build up concentrations from the Bethlehem Steel

process can be found in Table 2. Four ions from this list were used

as the dissolved solids to be removed from the gas scrubber water.

They ares (1) sodium; (2) calcium; (3) chloride; (4) sulfate. These

ions are made to enter the process in a fixed ratio (see Table 3).

The removal of the sodium and calcium ion is done by the use of

a cation exchanger resin. The resin used for the design was Dowex

HCR-W. The hydrogen fonn of the resin was used. To regenerate the

spent resin, a six per cent by weight aqueous solution of sulfuric

7

l

.t I

'

' 'i

.t

. DIRTY GAS

GS- I

T- 4

P,1

TC ST :.r;t

TO RIVER

ST E i\ f/

BLEED

/

\\

FIGURE NO·

REMOVAL OF SUSPEND AND DISSO'L\/ED SOLIDS FROM FROCESS WATER

CLEA~ GAS Cl -1

RE.CYCLE STREt-1/

C :-l • I

E \' - I

R - I

·' '

,. c:_.··

T - 5

T - 6

T - I

~------------------------·----.------

E 2 B-1

FEED

p - 8 P • 13 P - I 2

p - 10

T - 3

P- 9

FEE J

I - E,

I L

I ii

Ii

Gas Scrubbing Section

Name

Gas Scrubber Scrubber Head Pump Scrubber Pump Scrubber Feed Tank

Suspended Solids Section

Clarifier Clarifier Pump Rotary Drum Filter Recycle Pump Feed Pump to Hold Tank

Dissolved Solids Section

Hold Tank Cation Exchange Beds Feed Pump - Cat. Beds Backwash Pump - Cat. Beds Cation Regenerant Tank Cation Reg. Tank Mixer Anion Exchange Beds Feed Pump - An. Beds Backwash Pump - An. Beds Anion Regenerant Tank Anion Reg. Tank Mixer Product Pump Spent Regenerant Pump - Cl Spent Regenerant Pump - C2

Table 1

Ei~UIPMENT LIST

9

Equipment No.

GS-1 P-1 P-2 T-4

CL-1 P-3 F-1 P-4 P-5

T-1 B-1 P-6 P-7 T-2

MX-1 B-2 P-8 P-9 T-3

MX-2 P-10 P-12 P-13

Spent Regenerant Section

Name

Cation Spent Reg. Tank Anion Spent Reg. Tank Spent Regenerant Pump - C2 Spent Regenerant Pump - A2 Reactor Evaporator Bottoms Pump Condenser Condenser Pump Ejector Cooling Tower System

TABLE 1 ( cont.)

10

Equipment No.

T-5 T-6 P-14 P-15 R-1

EV-1 P-17

CN-1 P-18

EJ-1 CT-1

TABLE 2

PROCESS DATA OBTAINED FIWM BErHLEHF.M STEEL CORP.

Gas Flow Rate - 140,000 SCFM

Gas Composition -MOLE%

26 16 3

52 3

water Flow to Gas Scrubber - 12,000 GPM

Build up of Dissolved Solids in Bleed Steam -

ION PPM

Fe 2 Zn 40 Al 6 Ca 110 Mg 75 so4 900 Cl 800 Si02 30 Na 850

Amount of Filter Cake - 75 tons/day (dry)

Analysis of Filter Cake -

Fe C Zn Si0 2 Ca Mg Al20J

11

wt.%

65.6 7.8 3.3 6.4 2.9 2.1 2.3

--- . ----~---·-------·-··--. --------··--·----

TABLE 2 ( cont.)

Particle Size Distribution of Particule Entering Gas Scrubber

Wt. % of Total Stream

6.0 10.0 30.0 50.0 70.0 90.0 98.0

12

Size (Microns)

700 660 440 280 100

75 50

TABLE 3

BUILD UP RAT:ES* FOR DISSOLVED IONS IN RECYCLED GAS SCRUBBER WATER

ION Wt. fraction

Na 0.3195 Ca 0.0414 Cl 0.3008 so4 0.3383

1.0000

* For every pound of dissolvable solids in the gas stream entering the scrubber, the distribution will be constant and will be in accord with the values in the table.

13

acid was used. The chloride and sulfate ions were removed by the

use of Dowex SBR anion exchange resin. The resin has only a chloride

form, so the resin must be pretreated with the anion resin regenerant,

which is a four wt. per cent aqueous solution of sodium hydroxide.

The cleaned-up proces3 water from the ion exchance system is

essentially free from dissolved ions, except for leakage f'rom the

resin. This stream is then added to the scrubber feed tank, where

it is mixed with the recycle stream. The exit stream from the tank

should be the same concentration as the previous pass. If not the

amount of recycle should be adjusted accordingly.

The dissolved solid section also produces two waste streams:

( 1) spent sodium hydroxide solution; ( 2) spent sulfuric acid solution.

These two stream.s are added together in a reactor and the following

neutralization takes place:

::::

There is an excess of sodium hydroxide, so all the sulfuric acid is

used. The exit stream from the reactor goes to an evaporator to

concentrate the stream. The bottoma of the evaporator are sent to

a pond for final drying. The evaporator operates under vacuum so

that the overhead product, pure water, is at a temperature where it

can be used as make up water or dumped into the river. A two-stage

jet ejector with intercondenser was used to produce the vacuum for

the evaporator.

14

DESIGN MODEL - PROGRAM SOLIDS

Program SOIJDS was developed to simulate the process in Figure

1. The program does the calculations for the mass and energy balances

needed for each piece of equipment. These balances are then used to

detennine the sizes of all the pieces of equipment. The purchased

costs are then calculated by the use of analytical expression for the

available cost data. These costs are updated to January 1, 1973 by

the use of the Marshall and Stevens Index. The index at this time

was 336.7. Installed costs are also calculated for each piece of

equipment by using a materials and labor factor to correct the updated

purchased cost. The utilities needed, such as process water, steam

and electricity are calculated per section. A summary at the end of

each section gives the totals for each utility used.

All these calculations were set-up so that they are flexible.

This flexibility shows itself in allowing the user to change many

process variables in the system. The program shows the results in

changes of equipment sizes, costs and utility use. The user has con­

trol over this flexibility through the use of 41 data cards. F.ach

card contains the process variables for each piece of equipment. The

ion exchange system has six data cards to allow for changes in almost

all the variables in the system. The documentation for these data

cards can be round in the body of the program.

The program itself has documentation in each subroutine and in

the main line program explaining the logic and calculations involved.

The program also has a variable list in the main body of the program

to allow the user to follow the calculations. The documentation and

variable list are an important part of any program. Without them the

program becomes useless.

The overall design of the program has some strong points and

also some weaknesses. The program is able to handle the design of

pumps ranging from 12,000 GPM to 1 GPM. The cost data may need some

refinement, but the design mechanism can handle this range of flow

with no problem. This kind of flexibility is indicative of all the

pieces of equipment that are designed. The program also has physical

data programmed as a function of temperature to allow for temperature

changes in the system. To check on this flexibility the program pro­

duces a large amount of output. The user can find a printout of the

size, cost and process conditions for each piece of equipment. The

printout is well spaced so the user can find what he is looking for.

Program SOIJDS does have some weak points. One of the major

points is its treatment of the spent regenerant streams. The current

design uses neutralization and concentration to treat these streams.

This is not very efficient use of the regenerant streams. A more

efficient system to recover some of the spent regenerants is needed.

There also is a question about some of the cost data obtained

and the range it is valid to. The program Jan only give an order

of magni~ude cost for the process because of this uncertainty. The

16

program is also limited in its design range in amount of physical

data prograrruned and its range. This information on the design

range can be found in the subroutine which has the data stored.

17

ECONOMICS OF DESIGNED SYSTm

The calculation of the equipment costs by Program SOLIDS is

only part of the economic analysis of the system. The total capital

and operating costs are also needed to determine if the process is

economically promising. To do these calculations another computer

program was used. The program that was used, Program CAOPCO, was

written by the Bureau of Mines• College Park process evaluation

group. It was written by the group to be used on an IBM 7094 com­

puter. Dr. Alan S. Foust, McCann Professor, Department of Chemical

Engineering, Lehigh University, has taken this program and adapted

it for use on the CDC 6400 computer at Lehigh University.

The description and operation of the program can be found in

the Bureau of Mines Information Circular 8426. The circular also

gives a description of how the calculations are done and some of the

philosophy behind them. The data cards needed are listed in the cir­

cular along with the needed formats and an explanation to their ase.

Some documentation of the program and data cards can also be found

in the body of the program.

Program CAOPCO, as adapted by Dr. Foust, could not handle the

economics for the solids removal system. The program had been set

up to handle solids or liquids with operating costs in the order of

magnitude of$ 0,01 per unit of reference material and higher. The

costs tor the treatment of water are of th~ order of$ 0,10 per 1000

18

gallons and higher. On the basis of one gallon, the cost would be

of the order of$ 0.0001. The program will only handle operating

costs per one unit of reference material, so it had to be changed

to work with costs of this order of magnitude. Changes to the data

cards as set up by the Bureau of Mines' group can be found in the

Appendix.

The output taken from Program SOLIDS to be put into Program

CAOPCO is as follows, (1) purchased cost per piece of equipment;

(2) number of pieces of equipment; (3) size of piece of equipment;

(4) utilities used per section; (.5) total raw materials used per

day; (6) quantity of reference material per day. Program CAOPCO

needs much more data than this for it to run. The rest of the input

is in the fonn of factors to take into account, maintenance, labor,

supervision, operating supplies, etc.

One problem that occurred with Program CAOPCO was with the

handling of the steam. The program wanted to put in a steam plant

if any steam was needed, whether the user wanted it or not. To

solve this problem, no steam was specified as needed by the process.

The amount of steam needed, lbs. per day, was read into the program

in place of raw water needed. The cost for steam,$ 0.0005 per lb.

was read into the program in place of the cost for raw water. This

can be seen in the output from the program.

The output from Program CAOPCO was in tabular form, making it

' very easy to read. The equipment was listed by section with their

individual costs and sizes and a total sectional cost. After the

19

equipment lists the following tables can be found: (1) Estimated

Capital Cost; (2) EGtimated Working Capital; (3) Estimated Annual

Operating Costs; (4) Raw Material and Utility Requirements; (.5)

Direct Labor, Men Per Shift; (6) Daily Sectional Requirements.

One table was not used in the analysis, which was Estimated Selling

Price.

Program CAOPCO, when modified, was more than adequate to

handle the economics of the designed system. The costs from the

design model were not in all cases accurate, but rather approximate

cost. The economic analysis gave capital and operating costs which

also were approximate. These costs can be made more accurate by

making the factors which enter into the program more in line with

the actual process. Better equipment costs could also be used to

increase the accuracy. This though is not needed for this design

project because the main goal was the order of magnitude of the

costs.

20

! ;

CASE STUDY

In order to test Program SOLIDS for its flexibility and to see

what the economics are for the designed system, a study was run using

both computer programs. As mentioned in the Introduction, the amount

of dissolvable solids in the gas stream entering the gas scrubber was

unknown. The amount of suspendable solids entering was known at about

104 lbs. per min. By studying other blast furnaces using many differ­

ent types of ores as feed, it was concluded that the amount of dissolv­

able solids entering the gas scrubber was in the range of 10 lbs. per

min. The accuracy of this number is in question, but it was used.

This study and one made of the feed conditions at the Bethlehem Steel

furnaces indicate that this number may be too high. The value of 10

lbs. per minute was used as an upper limit and 2 lbs. per minute was

set as the lower limit.

Another variable thought to have an affect on the economics of

the process is the flow of water entering the gas scrubber. Table 2

shows that the flow for the actual process is 12,000 gallons per

minute. The question was then raised, what happens to the capital

and operating costs of the process if this flow is lowered? To ans­

wer it, the study was also set to include flows of 12,000, 10,000

and 8,000 gallons per minute. Lower flows were not used because many

of the process variables were set for these high flows.

21

The procedure used for the study was to run Program SOLIDS

using the upper limit for the dissolvable solids and then vary the

flow. The same procedure was also followed with the lower limit.

In order to run this study another process variable had to be con­

sidered. This variable was amount of water that was recycled with­

out clean up.

Program SOIJDS was set up to read in the concentration of the

dissolved solids in the water entering the gas scrubber. This con­

centration increases because the dissolvable solids in the gas stream

as washed by the water. The recycle factor tells how much of this

water is cleaned up and how much is recycled without clean up of

dissolved solids. These two streams are then mixed together in the

scrubber feed tank. If the concentration of dissolved solids in the

tank exit stream is the same as the value read in, then the correct

amount of water was recycled. If not, the amount of recycle has to

be adjusted.

The dissolved solids concentration for the water entering the

scrubber was read into Program SOLIDS as 2000 ppm. If the calculated

value was less than 2000 ppm, then too much water was cleaned up and

more water should be recycled. If the calculated value was higher

than 2000 ppm, then not enough water was cleaned up and less water

should be recycled.

The data from each correct run from Program SOIJDS was then

put into Program CAOPCO. The economics obtained are listed in Table

4. Figures 2 and 3 show the capital and operating cost for the

22

designed system as a function of the flow of water to the scrubber.

The amount of dissolvable solids in the gas stream entering the

scrubber was used as a parameter.

23

TABLE 4

~NOMICS FOR THE PROCESS

Dissolvable Solids into Scrubber

2.0 lbs/min. lO.O lbs/min.

Flow l2,000 l0,000 8,000 l2,000 l0,000 8,000

(GPM)

Capital Cost 2,022,320 2,054,590 l,855,330 3,399,740 3,307,650 3,226,980

I'\) {$) ::-

Opera ting Cost 723,856 717,787 665,172 1,682,594 l,657,457 1,645,425

($/yr.)

Operating Cost 0.13 O.l6 O.l9 0.32 0.38 0.47

($/lOOO gal)

Recycle 0.990 0.987 0.985 0.951 0.942 0.928

:. ' l '. ' '. .T ··1··.,1· .. , I

•• I ' ' " : ! .

' '

T I ·,··· ·: .. :T '. ·r· :·''!'···;····1··:· ·,

! :. I I : i ! : . I '

. I'. '· · I FIGURE~ NO •.. 2 . . I i ii

, I ' i ; ( \ :•

..... ~APITAL:: COf3T : vEks~s FLOW. ~~E. INTO GAS SCRUBBER ! I I \ . I I ' I ; .

! . ! I· '..:. I . :: ! ..

4.20 ! I

3.80

... i ..... : ..... I

3. 4 O·

I i I I 1

i I I I

• • I

I ':.

· \ I

',,,.

. . . .. ..... I. I :.. . , I I

i i

I

I

I . . . I .

! I

I i

I . I

I'

~o.o LBS/MIN DISSOLVABLE SOLIDS IN GAS STREAM

. ENTERING 'THE .SCRUBBER'

' . --·--. ·-·- ,-•-·-· ·-·

I . : I

. i ' . i· .

'

' '

•.•.•.•. . ....... : r T r I r : . .-• • • · •.. . ; i i . . I • I : F~GURE; NO, ... 3.

:~:···· +•·t·•··CRTt•nT•rRSUf>I {LOW ~T~ INTO GAS SCRUBBER ' .. ' I· ' I 'I ' I

-·-.. ···-·. : ': I : i I l I .•• ·- ••• 1 ···-~. ·---·· ••• ·-· ..... -· ' •••••• , •• ,_ .. , ·-· -- . -~---

1

.. , . · · · 1 · I : : : ' ' : \ ' I : " . i ' i ' . . II .

:·::::·"\":::: .. ·,1 .. : .... 1 .:: ::, ·:· i i -:; : : ';_ _ _:__.L~-~.: ... I ~--~-i . .: .. JQ_.:O_ LBS/MIN DISSOLVABLE. SOLIDS. IN. GAS STREAM.

: -:::. :. ::::· : : ] ! :: , .. ::·ENTERING ;THE .SCRUBBER • I • ' I

I : .. I l . ·1 ' I ) 1

/ I ' \

I -----~--75·-r -- ·- --·-i··--:----1---·--: . -1---·---- :·---:---:--··· ··--·- -J --·--- - -

• ' ·1 •••••• • •• I •• • t , , l ' , ,

I : .. I ' : : I ' ' 0

I , I!) l3

'r--• ; .. , . :: . ·······--·--·····------..l----····1· .. i

1 •

I . 1 . • . . .

i ' I " '

i--·- .. --1·. 5 o·-r · ----: · · -- ·-··: ... ----- : ______ :_ ---------·-- ·- --·--1 I I ! I ' 1 · • •: .... • . . • • • ' . . . I.. ' • . : • .. • ' .

I . . . r-~--·- ·-·-·--·--· _____ ,_' --··-----!.. :>; : : : I •• • • I '

. '-. ! ..... I ..

: ~ : ••••• ' ·- I • ·--·-·· ---·---·-·· __ ,_. ·--- -- ·-' ~--'(f)-·-1-.-2s- : - , - -------·------···------------·-----

' I , i .. I ' ...... .

I

... !. .. . : !·· . ,. ' I ,

1 __ . : . . L. ___ \ ___ · _.__ ___ ; --- - -- -----··---,.

'j

RllSULTS AND DISCUSSION

The results of the economic study show trends that were ex­

pected. Figure 2 shows the capital cost decreasing slightly as the

flow to the scrubber decreases. This is true of the 10.0 lbs. per

minute dissolvable solids rate. For the 2.0 lbs. per minute rate,

the curve shows a maxima at 10,000 gallons per minute. The capital

cost for the flow of 8,000 gallons was lower than that of 12,000

gallons per minute. The change in the capital cost for the two dif­

ferent dissolvable solid rates was appreciable. The capital cost

for 10.0 lbs. per minute rate is in the range of $3.3 million and

for the 2.0 lbs. per minute rate the cost was around $2.0 million.

These results show that the changes in flow have only a small

effect on the capital. This is true for both dissolvable solids

rates. As for the maxima which occurs in the lower dissolvable

solids rate, it is probably due to the design of the system. The

system was set up originally for higher fiows and dissolvable solids

rates. If all the variables were optimized for lower flows and sol­

ids rates then this maxima would probably disappear and the curve

would show the decreasing trend.

As for the difference in capital cost for the two solids rates,

the results show that the economics are very sensitive. The capital

cost dropped by $1.3 million for the drop in solids rate. This kind

of sensitivity says that more studies should be made to find the

27

,/

lk

economics of dissolvable solids rates inside and outside the range

in question.

The operating costs show the same decreasing trend. Again

there was an appreciable difference in operating cost between the

two solids rates. The operating cost for 10.0 lbs. per minute rate

was in the range of $1.6 million with about half of this cost used

on raw materials (regenerants). The cost for 2.0 lbs. per minute

rate was around $0.7 million and about one quarter of the cost was

used on raw materials.

The capital costs predicted by the Bureau of Mines are expected

to be within 30 per cent of the actual cost. An analysis of the pro­

gram shows it to be in the order of a study estimate. The study

estimate uses average factors to obtain costs and also a knowledge

of the major items of equipment. The value of! 30 per cent is also

listed in the description in the Bureau of Mines program as an esti­

mate of the accuracy of the capital costs obtained.

One of the most important questions to be asked of the entire

project is, will the design work? The design was based on known

technology and no new developments. The operating conditions and

the resin used in the ion exchange section were all suggested by the

Dow Chemical Co. literature. The other sections used standard pieces

of equipment and they were set for attainable conditions. Based on

this knowledge, it was estimated that the design will work. The

process conditions set may not be the optimum but they should make

the process run.

28

(X)NCLUSIONS AND RECOMMENDATIONS

It is quite evident that more work is needed in the area of

ion exchange for the removal of dissolved solids. The importance

of obtaining the best design is magnified by the fact that this type

of process produces no product which can be sold. The entire capital

and operating costs must then be absorbed by the existing facilities.

Better ways are needed to predict equilibrium relationships

between solids and liquids. Organic compounds have received a great

deal of attention for removal from process water, but what about

inorganic ions? Ion exchange technology has been used, but better

systems are needed for industrial waste streams with high flows and

dissolved solids concentrations.

Research is also needed in finding other methods for the re­

moval of dissolved solids. One method which shows potential is

removal by the use of membranes. An economic analysis must be done

on such a system to determine if it can be economically competitive

with ion exchange.

A smaller area of research needed is in the solubility of many

inorganic ions in solution. Physical data is needed to show the be­

havior of these ions in mixtures and also to predict the saturation

point for process water. It would seem that this type of research

may have to be done by the particular company with the dissolved

solids problem at the present time.

29

Design technology also plays an important role in solving the

problem at hand. It is obvious in ion exchange that a regenerant

recovery system is needed. This would show a decrease in the oper­

ating cost for the process. A possible approach to this problem

would be to recycle the regenerant and let the concentration of the

spent regenerant in the total stream build up to some point. Then

fresh regenerant could be added and some spent regenerant bled off.

What is also needed is another way to treat this spent regenerant

stream other than by neutralization. A comparison would then tell

which is the more economical way of treatment.

30

APPENDIX

Changes Made in Data Cards From Bureau of Mines Program

Data Card No. 5

Columns 13 - 18

Fonnat changed from F6.2 to F6.5

Data Card No. 12

Columns 1 - 7 changed to 1 - 12

Format changed from F?.O to Fl2.0

(rest of data card push back five spaces)

Data Card No. 13

Columns 50 - 59

Format changed from FlO.O to Fl0.7

31

r

REFERENCES

l. Applebaum, Samuel B. Demineralization by Ion Exchange. New Yorki Academic Press, 1968.

2. Aries, Robert S. and Newton, Robert D. Chemical Engineering Cost Estimation. New York, Chemonomics, Inc., 1951.

). Bethlehem Steel Corp. Bethlehem, Pa. Production records. July, 1972.

4. Chilton, Cecil H., ed. Cost Engineering in the Process Industry. New Yorkz McGraw-Hill Book Co., 1960.

5. Dahlstrom, D. A. and Cornell, C. F. "Thickening and Clarifi­cation," Chemical Engineering (4), Vol. 78 (1971), pp. 63-69.

6. Dow Chemical Co., Midland, Michigan. Ion Exchange literature.

January, 1973.

7. Dryden, Charles E. and Furlow, Richard H. Chemical Engineering Costs. Department of Chemical Engineering, Ohio State Uni­

versity, 1966.

8. Foust, Alan S., et al. Principles of Unit Operations. New York: John Wiley and Sons, Inc., 1960.

9. Happel, John. Chemical Process Economics. New Yorki John Wiley and Sons, Inc., 1958.

10, Harbison-Walker, Refractories Co. A Study of the Blast Furnace. Pittsburgh, 1911.

11. Johnson, Paul w. and Peters, Frank A. A Computer Program For Calculatin Ca ital and O eratin Costs, Information Circular

2 • U.S. Dept. of the Interior, Bureau of Mines, Washington,

D.c., 1969.

12. Kunin, Robert. Ion Exchan~e Resins, 2nd ed. New Yorks Wiley and Sons, Inc., 19 8.

John

13, Ludwig, Ernest E. Applied Process Design For Chemical and Petrochemical Plants. 3 Vols, Houstom Gulf Publishing

Co~, 1964.

32

14. McCabe, Warren L, and Smith, Julian C. Unit Operations of Chemical Engineering, New York: McGraw-Hill Book Co., 1967.

15, McGannon, Harold E. The Making, ShapinG and Treating of Steel. Pittsburgh, United States Steel, 196.

16. Perry, John H,, ed. Chemical Engineers' Handbook, 4th ed. New Yorks McGraw-Hill Book Co., 1963.

17, Peters, Max S. and Timmerhaus, Klaus D, Plant Design and Economics for Chemical Engineers. New Yorks McGraw-Hill Book Co., 1968.

18, Popper, Herbert. Modern Cost-Engineering Techniques. New York: McGraw-Hill Book Co., 1970,

19. Porter, H, F. "Filter Selection, 11 Chemical Engineering (4), Vol. 78 (1971), pp. 39-48.

20, Schweyer, Herbert E. Process Engineering Economics. New York: McGraw-Hill Book Co., 1955.

21. Stern, Arthur C, Air Pollution, Sources of Air Pollution and Their Control, Jrd vol. New York: Academic Press, 1968.

22, Strassburger, Julius H., ed. Blast Furnace - Theory and Practic~ 2 vols. New Yorks Gordon and Breach Science Publishers, 1969,

23, Strauss, W. Industrial Gas Cleaning, New Yorks Pergamon Press, 1966.

24. Strauss, w. Air Pollution Control, Part 1. New Yorks Wiley­Interscience, 1971,

25, Sweetser, Ralph H, Blast Furnace Practice. New York: McGraw­Hill Book Co., 1938.

26. Vilbrandt, Frank C. and Dryden, Charles. Chemical En ineerin Plant Design. New Yorks McGraw-Hill Book Co., 19 9,

27. Weast, Robert C., ed. Handbook of Chemistry and Physics, h 7th ed. Cleveland: The Chemical Rubber Co,, 1966.

28. Weber, A. P. "Selecting Turbine Agitator," Chemical Engineering (25), Vol. 71 (1964), PP• 169-174.

· 29. White, Walter F. Chemical Character of Surface Water in Penn­sylvania, 1946~1949, Pennsylvania Department of Commerce, State Planning Board, 1951.

33

VITA

The author was born on May 4, 1949 in Passaic, New Jersey to

Bruno and Frances Kopec. In June of 1967, he graduated Garfield

High School with honors and in the Fall of 1967 he entered Newark

College of Engineering. The author received a B.S. in Chemical

Engineering in June of 1971 from this institution.

Upon completion of the requirements for a Masters Degree in

Chemical Engineering, the author went to work for E. I. DuPont de

Nemours and Co. at Deepwater, New Jersey as a development engineer

in the Elastomers Division.

34

I

I . -- -- .. . ___________________ \ __