United States
Environmental Protection
Agency
Industrial Environmental
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S2-84-125 Sept. 1984
Project Summary
Solvent Recovery at Vandenberg
Air Force Base
Graham E. Harris
The operation of Vandenberg Air
Force Base (VAFB) as the western
launch site for the space shuttle will
increase the volume of solvent waste
generated. This report gives results of a
feasibility study of the addition of vapor
recovery and solvent purification equip-
ment for VAFB to reuse the large
quantities of waste solvent generated in
shuttle preparation operations. This
project—sponsored by the US Air
Force, with project direction provided
jointly by the Aerospace Corporation
and the US EPA—included four major
tasks: development of (1) design
criteria, (2) a conceptual design, (3) a
site layout and solvent logistics plan,
and (4) detailed system design specifi-
cations. It was determined that vapor
recovery can be justified at only one
location, and that Freon-113 is the only
solvent that can be economically
purified for reuse. The final system
design calls for a carbon adsorption
unit for recovery of solvent vapors from
the component cleaning facility (CCF)
and a solvent purification facility that
includes a water-wash column, two
fractional distillation columns, molecu-
lar sieve driers, and two-stage filtration.
It has been recommended that both
facilities be adjacent to the CCF, and
that a bulk Freon system be installed for
the CCF to reduce the handling of
containerized solvents.
This Project Summary was developed
by EPA's Industrial Environmental
Research Laboratory, Research Triangle
Park, NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Introduction
When Vandenberg Air Force Base
(VAFB) is fully operational as a launch site
for the space shuttle, the generation of
solvent wastes will increase by an order
of magnitude over current levels. This
report gives results of a study to determine
if it is economically feasible to recover
some of that solvent waste on-site and, if
so, the design of a system to recover the
solvent.
Waste Solvent Inventory
Waste solvents will be produced by a
variety of shuttle-related and -unrelated
processes at VAFB. Some of these
processes are strongly influenced by the
shuttle launch rate; others are indepen-
dent of it. All available data concerning
the projected rates of waste solvent
generation have been combined into a
computational data base which is keyed
to the launch rate. Preparation of this
data base has been a significant part of
this study, since both the economics and
the design of a solvent recovery system
depend on these data.
The latest figures indicate that waste
solvent generation will exceed 70,000
gal./yr (265,000 liters/yr) by 1995,
based on attaining a rate of nine launches
per year by that time. (See Table 1.) The
solvent Freon-113 is by far the largest
component in the projected solvent
waste, with an estimated concentration
of 64 volume percent. The next most
concentrated solvent species is methylene
chloride, which is present at only 6.2
volume percent. It was determined that
all other solvent species could not be
economically recovered in the prelimi-
nary economic evaluations. Conceptual
-------
Table 1 . Summary of the Liquid Solvent Waste Generation Rates (in G a/Ions f
Year 1986 1990 1995 Total
Component/ Launches 149 47b
Freon
IC3OH
MEK
MECL
PERC
1 1 1 TCEA
TRICH
MIBK
TOLUENE
ACETONE
ETH ACET
XYLENE
EGMBE
ETHANOL
ME DIANIL
C RE SAC ID
FORM ACID
AMMONIA
N-BUTANOL
CYHEXONE
NAPHTHA
PHENOLICS
HEXANE
PHOSACID
MIN SPIRT
RAM 225
FREON- 11
ETH BENZ
CARB TET
METHANOL
UNKNOWN
DETERGENT
TURCO
AMINES
AROMATICS
KETONES
CHROMIUM
GLYCOL ET
ALCOHOLS
CELL ACET
WATER
INK
SOLIDS
GREASE
DIRT
OIL
STODDARD
PD-620
Grand Totals
14346
1929
753
9O3
627
665
1364
170
267
204
;
17
18
107
11
37
5
0
2
2
21
5
2
30
163
0
20
19
20
815
839
1
3
5
10
19
5
5
11
5
187
0
458
2
2
155
2392
25
26646
32416
1286
1539
2734
2187
545
171
260
355
263
3
24
28
416
44
146
19
0
6
6
29
20
9
30
163
0
20
19
20
143
926
4
10
20
40
19
20
20
41
20
397
0
744
2
2
230
2392
25
47815
45793
1384
2872
5786
4786
896
154
411
502
360
6
35
45
931
99
329
43
0
14
14
42
45
20
30
163
0
20
19
20
143
720
9
23
45
90
19
45
45
91
45
748
0
1220
3
3
356
2392
25
70841
327484
17896
17285
31614
25506
7263
641 1
2813
3755
2764
33
253
305
4885
517
1720
226
0
75
75
311
235
106
300
1625
1
198
192
200
5794
8088
46
118
235
470
192
235
235
478
235
4466
3
8108
22
21
2478
23920
248
509437
Vol %
64.28
3.51
3.39
621
501
1.43
1.26
0.55
0.74
0.54
0.01
0.05
0.06
0.96
0 10
034
0.04
0.00
0.01
0.01
0.06
005
0.02
006
032
0.00
0.04
004
004
1 14
1 59
0.01
002
005
009
004
005
005
009
005
088
OOO
1 59
000
000
049
4 70
005
10000
unit at Kennedy Space Center, but it was
later learned that the unit planned for
VAFB would probably use different
technology (either non-Freon cleaning or
Freon-based cleaning in an enclosed unit
with its own integral vapor-recovery/sol-
vent-purification apparatus). As a result
of this, vapor recovery facilities were
found to be warranted only for the
component cleaning facility.
The recommended system consists of a
carbon adsorption unit (to recover Freon
vapors from the component cleaning
facility) and a purification unit (to upgrade
the Freon in the liquid waste solvent
stream to meet Type I military specifica-
tions) The purification unit includes a
water-wash column, two fractional
distillation columns, molecular sieve
dehydrators, and a two-stage filter (plus
an assortment of tanks, heat exchangers,
and piping to integrate the major compo-
nents). (See Figure 1.) A microprocessor-
based control system improves quality
control and minimizes the need for
operator intervention/sophistication.
The vapor recovery and purification
units should be adjacent to, or inside, the
ultimate site of the component cleaning
facility. This would allow installing a bulk
Freon-113 handling system for the
component cleaning facility, which is
projected to be by far the largest user of
the solvent. It would also allow flexibility
in allocating manpower requirements
between these compatible operations, as
well as sharing of utility systems.
The use of a bulk system at the
component cleaning facility will greatly
reduce the need for handling drums of
spent and reclaimed solvent. This is
highly beneficial in limiting labor costs
and in reducing worker exposure to the
potentially hazardous solvent waste. The
few spent solvent streams from other use
areas that are suitable for Freon recovery
will be handled as a special disposition
Management Plan at VAFB
1 / gal. =379 liters
' Maximum number of launches over 10-year period
designs were developed for two purifica-
tion facilities' one to recover only Freon;
and the other, both Freon and methylene
chloride After evaluating the cost of
these two systems and their respective
savings in solvent costs, it was determined
that there was no economic incentive to
recover the methylene chloride at the low
levels present in the composite solvent
waste feed.
Solvent Recovery System
The use of solvent vapor recovery units
was also considered for each existing, or
planned, solvent use area at VAFB. The
preliminary economic analysis eliminated
all but two areas: the component cleaning
facility and the SCAPE suit cleaning
facility The preliminary analysis for the
SCAPE suit cleaning facility was based on
the use of a process similar to the existing
System Economics
The installed capital cost of the
purification system is estimated to be
$795,000, the cost of the vapor recovery
unit is estimated to be $330,000. It has
been assumed that the total investment
of $1,125,000 in solvent recovery equip-
ment would be financed with an interest
rate similar to that currently paid on
Treasury Bonds (about 11.75 percent).
The gross saving in solvent costs over the
10-year project life—using a fresh Freon
price of $9.74/gal. ($2.57/liter), and
deducting $1 90/gal.($0.50/liter)forthe
-------
Water-
Soluble Waste
CWf
Distillation Columns
Waste Solvent,
from Drums '
i Waste Solvent
Feed Mix
Tank
Off-Spec
Return Line
Water-
Wash
Column
Water \
To Clean
Drums
Final
Product
Molding Tank
u
" -*•
X
X
X
A-
-»> CW
Primarily
-»* MaClto
Waste Dru
• (85
H'l
i]
J
«-
tembrane
Filter
£
S
f
ms
He
xchai
U
X
X
X
at
igers
intered
Steel
Filter
-9»
CWf-^T\-^
Freon ~~
Decanter
• 1 (• Heavy i "••
/-)nfx> Solvent
[000] ^ Waste _^
1 1 ^—^— — ^^r^ Wfitcr
f Molecular ~\ .£.
^ S/eve Or/er y
A Molecular ~\ A
1 S/eve Or/er J P"-!""^
Figure 1. The base case purification facility.
loss of offsite recovery potential—is in
excess of $3,720,000. Assuming a 10-
year economic life cycle and using the
Treasury Bond interest rate as the
discount factor, the net present value
of the investment in solvent recovery
equipment is $118,550 (expressed in
constant-value 1983 dollars). (See Table
2.) If a 5-percent general inflation
rate is added to the calculation, the
net present value of the investment in-
creases to about $530,000. That is
equivalent to an internal rate of return
or 19.45 percent, or a simple payback
period of about 5.3 years.
More recent information indicates that
the launch rate may peak at about four
launches per year and that the full
activation of ground support facilities
may be delayed until 1989. Although this
information arrived too late to be incor-
porated in the main design and economic
calculations for this study, some estimates
were made of the probable impact of
these changes on the economic viability
of the solvent recovery project. The
Table 2. Net Present Value (NPV) Calculations (Inflation Excluded Basis) for Combined
Purification and Vapor Recovery Units
Year
(A)
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
Totals
Value of
So/vent
Recovered
S/Year
(B)
0
157290
260707
260707
325133
368794
408509
441967
472337
499913
525360
3720716
Annual
Operating
Expenses
S/Year
(C)
0
70865
104012
99464
119417
131845
131933
140430
148086
154988
171444
1272484
Annual
Cash
Flow
$/Year
(Dj=B-C
0
86425
156695
161243
205716
236949
276576
301537
324251
344925
353916
2448232
Net
Annual
Cumulative
Discounted
Discount
Factor, %
11.75B
(E)
1.00
089
O.80
0.72
0.64
0.57
0.51
0.46
0.41
0.37
033
Cash
Flow
$/Year
(F)=D*E
0
77338
125476
115541
131910
135962
142014
138550
133322
126910
116526
1243549
Capital
Expendit.
$/Year
Net
Present
Value
S
(G) Sumof(G-F)
J 125000
0
0
0
0
0
0
0
0
0
0
1 125000
-1125000
-1047662
-922186
-806645
-674735
-538773
-396760
-258209
-124887
2023
118549
1 18549
aThe discount factor was set at the interest rate for long term Treasury Bonds, which was 11 75%
according to the Wall Street Journal of December 13, 1983
-------
reduction in launch rate, and the corres-
ponding reduction in waste solvent
generation rates, decreases the potential
gross savings That effect is more than
offset, however, by the delay in system
construction, since the marginal years of
operation (with only one or two launches)
are eliminated The preliminary calcula-
tions indicate that the net present value
of the project would be $637,850, which
corresponds to a 21.6 percent return on
investment These figures are based on a
10-year project life (1989 to 1998), a total
of 39 launches (3 m 1989 and 4 in each of
the remaining years), a 5-percent general
inflation rate, and an 11.75 percent
discount rate
Conclusions
The construction of onsite solvent
recovery facilities will create several
benefits in addition to the economic
incentives. Although no existing environ-
mental regulations would force VAFB to
control the atmospheric emissions of
Freon-113, the compound is under study
m EPA's National Emission Standards for
Hazardous Air Pollutants (NESHAP's)
program, and could require control as a
hazardous air pollutant in the future. Note
that aerosol propellant uses of the
halocarbons have already been prohibited.
Onsite recycling/reuse of this large
component of the liquid solvent waste is
also very much in line with the policies
expressed in California's recent Executive
Order to strictly limit any land disposal of
organic wastes. Investment in the solvent
recovery project will result in a hedge
against future price increases for Freon
and improved reliability of the supply for
this vital solvent.
G. E. Harris is with Radian Corporation. Austin. TX 78766.
Bruce A. Tichenor is the EPA Project Officer (see below).
The complete report, entitled "Solvent Recovery at Vandenberg Air Force Base."
(Order No. PB 84-222 405; Cost: $13.00, subject to change) will be available
only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
if U S GOVERNMENT PRINTING OFFICE, 1984—759-015/7806
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
------- |