W U K E M W5z.D

CORPORATION

NKD PROCESS FOR EXTRACTIVE

3000 Richmond Avenue Houston, TX 77098

Fax (713) 520-0538 (713) 520-9494

TREATMENT OF REFINERY OILY WASTES

by:

DR. MICHAEL J. MASSEY Vice President & General Manager

and

DR SAEED DARIAN Technology Manager

to:

COMMlllEE ON REFINERY ENVIRONMENTAL CONTROL American Petroleum Institute

OCTOBER 2, 1990

NKD PROCESS FOR EXTRACTIVE TREATMENT OF REFINERY OILY WASTES

4.

Dr. Michael J. Massey and Dr. Saeed Darian‘

SUMMARY

NukEM Development (NKD), a division of American NuKEM Corporation, is nearing completion of development work on a technology which overcomes inherent problems associated with previous efforts to apply solvent extraction techniques to the treatment of refinery oily wastes. NKD expects to complete 4 BPD pilot scale testing of its process within the next three months. In that same period of time NKD also expects to complete the design basis that is necessary for transfer of the technology to its sister division, ENSR Environmental Systems. ENSR Environmental Systems hopes to perform a commercial demonstration of the technology by the end of 1991, preferably in a refinery with a capacity of at least 100,000 BPD. Pilot scale results available to date verify the viability of the technology for virtually complete removal of oils from solids and water in a wide range of refinery oily wastes.

Y

173

NKD’s technology employs nontoxic, refinery-based solvents. The system processes oily wastes on a once through continuous basis without pretreatment. The resulting solids are virtually hydrocarbon-free and meet all BDAT standards. Recovered oil is recycled to refining operations; recovered water is processed in the refinery’s wastewater treatment facilities.

INTRODUCTION

NKD’s system for the treatment of refinery oily wastes is predicated upon inventions which trigger the single-step release of hydrocarbons from mixtures of water, solids, and hydrocarbons. These inventions make it possible to transfer virtually

’Drs. Massey and Darian are Vice President & General Manager and Technology Manager, respectively for NuKEM Development (formerly ENSR Technology), a division of American NuKEM Corporation. American NuKEM acquired ENSR Corporation and its division, ENSR Technology, in May of 1990.

' 174

all hydrocarbons present in such mixtures into water-immiscible solvents.' Transfer takes place at ambient conditions and is effected independently of the water content of the mixture. The technology is effective regardless of whether the continuous phase of the mixture is solid (e.g., contaminated soil), hydrocarbon, or water.

NKD presented an initial report on the application of its proprietary extraction techniques to the treatment of refinery oily wastes in February of this year? The present paper reports on the pilot scale program which has been conducted since that report. Key elements of this program include:

0 measurements of the performance capabilities of the technology on a range of oily wastes;

0 tests of alternative process flow sheets (PFD's) for application of the technology; and

e assembly of detailed technical data necessary for the scaleup, design and construction of a first commercial scale system.

DESIGN BASIS FOR NKD TREATMENT SYSTEM

The following major elements comprise the technical basis for NKD's specification of its refinery oily waste treatment process:

e Regulatory factors

. Technical factors

e Feedstock definition

0 Operating profile

'Patents pending.

3Ma~~ey , M.J. and Saeed Darian, "ENSR Process for the Extractive Treatment of Refinery Oily Wastes," Presentation at a Joint EPA and Air and Waste Management Association Meeting in Cincinnati on February 5-9, 1990.

175

Reaulatory Factors

The NKD process is designed to avoid the need for a RCRA permit through its function of recovering and recycling virtually all of the oil from refinery oily wastes back to refining operations under 40 CFR 261.6. Solids recovered from the process can then be stabilized, either onsite within the process or offsite, to attain the applicable Best Demonstrated Available Technology (BDAT) standards found in 40 CFR 268.41. Water recovered in the process is readily processed within the main refinery wastewater treatment facilities. Oil returned to the refinery is exempt under 40 CFR 261.6 from the Hazardous-Waste-as-Fuel regulations of 40 CFR Part 266 Subpart D.

The NKD process is designed to perform as a refinery processing unit rather than as a waste treatment unit.

Technical Factors

NKD has focused its design basis efforts on those factors which we believe are of greatest concern to refiners in the configuration of process equipment for their use:

1. No Pretreatment:

The NKD process is designed to operate directly on raw refinery oily wastes, thereby bypassing the need for cumbersome and costly pretreatment. The vast majority of refinery oily wastes exist as bulk water streams with small amounts of oil and solid. Conventional practice involves maximum effort to reduce the volume of this waste through filtration.

2. Simple, Packaged Plants:

The number of unit operations, the sizing and selection of process equipment, and the configuration of control systems are selected to preserve simplicity and the economics available from modular skid construction.

3. Continous, Ambient Operating Conditions:

The system is designed to perform continuously at ambient temperatures and pressures with minimal supervision. No specialized expertise beyond that routinely available within the refinery is required for reliable operation of the system.

4. Non-Toxic Chemicals:

No chemicals employed in the NKD process appear on any EPA or state environmental agency lists as dangerous or hazardous chemicals.

176

5. Refinery-Based Solvents:

Solvents employed in the NKD process are readily obtainable within most refineries.

Feedstock Defi nition

Refinery oily wastes are actually comprised of sludges of varying composition and a wide range of different sources. To simplify NKD process design considerations, NKD has defined two generic oily sludge feedstocks whose characteristics were chosen to span the range of actual oily sludge characteristics typically encountered within a refinery.

1. Primary Feedstock:

The first generic oily sludge, referred to as the Primary Feedstock, was modeled as a mixture of API separator sludge (EPA Waste Code K051) and dissolved air flotation (DAF) float (€PA Waste Code KO48). NKD has defined the following composition for Primary Feedstock: 70 % water, 15 % oil, and 15 % solids. NKD believes that Primary Feedstock covers the bulk (perhaps as much as 90%) of oily sludges encountered within a typical refinery.

2. Secondary Feedstock:

The second generic oily sludge, referred to as Secondary Feedstock, was modeled after slop oil sludge (including EPA Waste Code KO49). Secondary Feedstock covers oily sludges which are generated sporadically and in highly variable amounts. NKD has defined the following composition for Secondary Feedstock: 55 % water, 15 % oil, and 35 % solids.

3. Feedstock Exclusions:

The only oily wastes specifically excluded from the NKD process system designed for treatment of refinery oily wastes are those which:

0 contain combinations of oil and solids which comprise 2 50% of the sludge mixture; and/or

0 have particle sizes greater than about 60 mesh.

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177

These materials act more like solids contaminated with oil and therefore require treatment in an NKD process system specifically designed for the treatment of contaminated

\

Definition of Svstem ODeratina Profile

I I For discussion purposes, NKD selected the following NKD process system

operating profile for the treatment of refinery oily wastes. It is recognized that actual operating profiles will vary from refiner to refiner. The basic system design discussed here can be easily modified to account for such differences.

As presently envisioned, a standard module of the NKD process would be sized to operate on oily wastes produced from a 100,000 BPD refinery. Raw API/DAF sludge production (Primary Feedstock) is assumed to be 10,000 tons/yr5; slop sludge production ' (secondary feedstock) is assumed to be 1,000 tons/yr.

Raw wastes are charged to Primary Feedstock and Secondary Feedstock storage tanks, respectively, at regular intervals. Tankage required for this mode of operation on a weekly basis is 1,000 barrels and 100 barrels for Primary Feedstock and Secondary Feedstock, respectively.

Primary Feedstock is drawn from the above storage tanks at a fixed continuous rate. For weekly intervals of operation, flows would be about 350 BPD (10 gal/min) for approximately 4 days per week. During the fifth day, Secondary Feedstock would be processed continuously at rates ranging from 35 to 175 BPD depending upon the physical characteristics of the specific waste sludge. The remaining two days of each week would be dedicated to recharging of the storage tanks, characterization of the fresh tank compositions, and establishment of basic operating conditions for operation of the NKD process treatment system on the new load of oily waste sludge.

'N KD has discussed the application of its solvent extraction techniques to the treatment of contaminated soils in a separate publication: "ENSR Process for the Extractive Treatment of Soils and Sludges," Proceedinas of the PCB Forum, August 29- 30, 1989.

'Standard composition: 70 % water, 15 % solids, and 15 %oil.

' Included in this category are tank bottoms and slop oils. Exclusions include oil- laden spent catalyst (due to particle size of the solids).

PROCESS FLOW DIAGRAM (PFD) AND MATERIAL BALANCE

Figure 1 provides the process flow diagram (PFD) and material balance for the NKD process system for the treatment of refinery oily wastes. The material balance presented in Figure 1 is based upon the operating profile outlined above which involves the processing of 350 BPD (approximately 10 gal/min) of Primary Feedstock.

The NKD process presented in Figure 1 involves the following basic unit operations and equipment:

Unit Operation Equipment

1. Oil Removal from Solids/ Water

2. Solids Dewatering

3. Solvent Recovery (Optional)

0 Liquid-Liquid Counter-current Extractor

e Residual Solvent Stripping

0 Filtration

Fractional Distillation

Oil Removal From Solids/Water

Raw sludge (7'0% water, 15% solids, 15% oil) is removed from a nominal 1 ,OOO barrel storage tank at 350 BPD (10 gpm) and combined with a small amount of refinery based sOlvent and a measured amount of proprietary NKD process reagent. The resulting mixture is then injected into the top of a multistage liquid-liquid counter- current solvent extraction column. This column is nominally 30 inches in diameter and 35 feet tall.

Solvent is injected into the base of the liquid-liquid extraction column at a nominal flow rate of 700 BPD (20 gpm). Solids and water cascade down the column while solvent migrates up the column extracting oil as it rises. Oil-laden solvent exits the top of the column; oil-free solids and water exit the bottom of the column.

c

FIGURE 1 PROCESS FLOW DIAGRAM AND MATERIAL BALANCE:

NKD PROCESS FOR EXTRACTIVE TREATMENT OF REFINERY OILY WASTE

REAGENT L -L

RAW (4) FEED

LIQUID- LlWiO EXTRACTOR

15% OIL 15% SOLIDS 70% WATER

RESIDUAL SOLVENT REMOVAL (11) WATER TO

TREATMENT

T (9) (lo) SOLIDS TO OESPOSAL

FltTER

* 180

Solids Dewaterinq

Solids and w a a from he bottom o the liauid-liauid extraction co umn are pumped through a solvent stripper where residual solvent is stripped from the mixture. The resulting slurry of pure solids and water is then pumped to a filtration unit wherewater is removed and the filter cake is accumulated in a rolloff bin for shipment to a disposal site for stabilization, if necessary, and landfill disposal.

Optionally, filter cake can be combined with appropriate reagents and stabilized as a part of the NKD processing system.

Solvent Recovew

Oil-laden solvent is processed through a fractional distillation column for the recovery and recycle of solvent. Reasonable recoveries are achieved at reflux ratios of about 1:l. Total heat duties involved are small ( 1.5 to 2.5 MMBTU/hr depending upon the degree of heat integration employed). Recovered oil is recycled to the refinery crude oil fractionation unit, coker, or FCC unit.

Optionally, oil-laden solvent can be returned directly to the refinery crude oil fractionation unit, thereby simplifying the NKD processing system. Under such circumstances, the NKD process does not include a solvent distillation system; instead it receives fresh solvent from a storage tank and sends oil-laden solvent back to the refinery.

PILOT SCALE TESTING OF NKD PROCESS

NKD has built and operated a scalable 4 BPD pilot plant which closely follows the PFD outlined in Figure 1. This pilot plant has been operated successfully on a continuous basis on raw oily waste sludges from several different refineries in the Gulf Coast area. Test materials have included API separator sludges and DAF float sludges that have been both pumped from and otherwise removed from pits or tanks. Test materials have also included samples of "other" oily wastes which have been removed from slop dumping pits which receive oily wastes from a wide variety of process and spill cleanup sources.

The present discussion focuses on test work associated with two feedstocks with significantly different oily sludge characteristics. Basic characteristics of the pilot plant are described first. Feedstock characteristics and overall process performance are then cited. Finally, performance of individual unit operations are discussed in some detail.

181

Pilot Plant Con fiauration and Size

The heart of the NKD pilot plant is a 3-inch diameter liquid-liquid countercurrent extraction column containing a total of 36 actual extraction stages in an overall column height of 4 feet. This column was selected for its known scaleup characteristics. Its scalability readily supports the scaleup factors of between 50 and 100 which were anticipated from pilot-scale to commercial-demonstration-scale sludge processing rates (2 to 4 BPD pilot scale and 200 to 400 BPD commercial scale).

The pilot plant also contains a complete fractional distillation column for the

The pilot plant also contains a series of alternative solids dewatering devices

processing, recovery, and recycle of solvent.

(e.g., plate and frame filter press, belt filter press, vacuum filter) suitable for determination of the optimal equipment selection for this unit operation.

collecting of various process streams identified in the PFD outlined in Figure 1. Finally, the pilot plant contains pumps and tanks for the mixing, feeding, and

Pilot Plant Feedstock Characteristics

The two contrasting feedstocks discussed in this paper have the following basic characteristics:

Component API Separator Slop Sludge (Primary) (Secondary)

% Water 81 % 78 %

% Solids 9 % 16 %

% Oil 10 % 6 %

The sample of API separator sludge (example of Primary Feedstock) was taken directly from the API separator pit of a major Gulf Coast refinery. The sample of slop sludge (example of Secondary Feedstock) was taken from a waste oil dumping pit that receives sludges from vacuum trucks. These vacuum trucks pick up slop oil from throughout a major but different Gulf Coast refinery.

Pilot Plant Product C haracteristics

Characteristics of the product oils recovered from the samples of API separator and slop sludge, respectively, are presented in Figure 2 in the form of true boiling point

182

,

cutves. As might be expected based on the origins of these different samples, recovered oils from these samples have very different characteristics. The oil recovered from the sample of slop sludge is heavier than that recovered from API separator sludge. To be successful, an oily waste sludge treatment process must be capable of coping with both (a) the large differences in oil characteristics from one sludge to the next, and (b) the wide range of boiling points of hydrocarbons present in a typical oil contained in an oily waste sludge.

Residual hydrocarbon characteristics of the solids and the water produced from the treatment of API separator sludge in the NKD process pilot plant are presented in Table 1. Also included for comparison purposes are applicable solid and water BDAT standards. By exception do treated solids contain anv organics at the levels of analytical detection. Basic chromatographic data presented later in this report (Figure 4) suggest that similar results can be expected for the products of slop0 sludge processing. Table 1 results clearly show that NKD process treatment results in virtually complete removal of oil from both water and solids present in raw API separator sludge. Applicable BDAT hydrocarbon standards are met in every instance without resort to stabilization of the products produced.

Metals characteristics of the solids produced from the treatment of API separator sludge in the NKD process pilot plant are presented in Table 2. Test work reported in Table 2 is preliminary in that optimization of the types and quantities of stabilizing chemicals actually required for passage of BDAT TCLP requirements has not yet been completed. However, available results are sufficient to confirm that stabilization of solids resulting from NKD process treatment to and below BDAT standards is readily achievable.'

Pilot Scale Liquid-Liauid Extraction Svstem

The advantages of performing the extraction of oil from oily waste sludges in a single, counter-current liquid-liquid extraction column are substantial. They include:

1.: Avoiding the need and cost for a series of mixer settler tanks, one for each desired stage of extraction.

2. Avoiding the need and cost for pumps to move solvent and waste from one stage of mixer settler tanks to another.

3. Avoiding the need and cost for spare equipment to insure reliability of overall train of extraction equipment.

'Similarly detailed data are presently being developed for the slop oil sludge.

-

183

FIGURE 2

CHARACTERISTICS OF OIL RECOVERED FROM PILOT SCALE TESTING OF NKD PROCESS

700 -

600 -

500 -

400 - 301LING POINT,

=F 300 -

200 -

100-

0-

-* API SEPARATOR OIL(*)

I I I I I I I 1 I 10 20 30 40 50 60 70 80 90

% DISTILLED

NOTE: (1) Material cracked at 624T.

(2) Recovery - 90% ; Residue - 5% Recovery - 75% ; Residue - 259,

184

TABLE 1

FATE OF ORGANICS IN PILOT SCALE TREATMENT OF API SEPARATOR SLUDGE

Raw Filtered Filtered BDAT Standard Sludae Solids Water Solid Water

Benzene Ethyl Benzene

Toluene.

Xylene

Phenol

bis-(242Moroethyl) Ether

4Methylphend @cresol)

2-Nitrophend

2.CDimethylphenol

bis-(2Chloroethoxy) Methane

2,CDichlorophend

Naphthalene

GhloroanUine 2-Methylnaphthalene

GMoro3-methylphend

2,4,5-Trichlorophend

P-Chloronaphthalene

2-Nitroaniline

3-Nitroaniline

2,4 Dinitrophenol

Dibenzofuran

2,4-Dinitrotduene

4,-Nitrophend

fluorene 42hiorophenyl-4 -Nitroaniline

4.6-Dinitro-2-methyl- phend N-Nitrosodiphenylamine

Phenanthrene

434 1 42

359

939 16.41 (')

1.16

1.08

5.03

5.55

1.5

10.40

1 .oo 7.78

79.5

1.7

2.39

1.78

20.8

22.2

8.02

1.11

20.3

43.3

ND

ND

ND

ND

ND

3.35")

ND

ND

ND

ND

ND

ND

ND

ND

2.72

ND

ND

ND

0.79

ND

ND

ND

ND

1.62

ND

ND

ND

ND

ND

0.58'" ND

0.09

ND

ND

NO

ND

ND

ND

0.3

ND

ND

ND

0.09

0.08

ND

ND

ND

ND

ND

14

14

14

22

3.6 -

0.01 1

0.01 1

0.01 1

0.01 1

0.047 -

0.033 -

- 0.054

1.06 ND ND - -

102.5 ND ND - 5.76 ND ND - -

ND ND No 34 Q038

185

TABLE 1 ... Cont’d

FATE OF ORGANICS .... API SEPARATOR SLUDGE

Anthracene

Dibutyl Phthlate

Pyrene

Benzo(a)anthracene

Chrysene

3,3’-DichlorobenzMine

bis-(2ethylhexyl) Phthlate

di-n-octyl Phthlate

Benzo(a) pyrene

Indeno(1,2,3cd)pyrene

Benzo(g,h,i)perylene

NOTE:

Raw Filtered Sludge Solids

16.7

ND

2.9 ND

2.91

1.37

5.31

ND

ND

1.88 3.10

ND

ND

ND

ND

ND

ND

ND

ND

ND

ND

ND

Filtered BDAT Standard Water Solid Water

ND

0.10

ND

ND

ND

ND

ND

0.08

ND

ND

ND

28

3.6

14

20 1 - 7.3 -

12 - -

0.039

0.06

0.01 1

0.043 50.043 -

0.043 - 0.047 - -

(’I The phend readings reported are highly suspect. Extremely low levels of phend were reported in the raw sludge (ppm). Phend is highly soluble in water; it is also soluble in NKD process solvent. In spite of this and the very large quantities of both present, the analytical data suggest limited dissolution of phend.

186

TABLE 2

LEACHABILITY OF METALS IN SAMPLES OF PILOT SCALE PROCESSED API SEPARATOR SOLIDS

TCLP. ppm

As

As

Ba

Cd

Cr

Hg

Ni

Pb

Se

Metal Content of Dry Solids

DDm

< 1

5.2

940

5.7

220

35

75

100

1 .o

Stabilized (la Detection Sample Limit

< 0.01 0.01

0.002 0.01

1.6 0.02

< 0.01 0.01

< 0.02 0.02

< 0.001 0.001

< 0.02 0.02

< 0.025 0.025

< 0.005 0.005

NOTES:

('I Test sample was stabilized with 0.5 units of stabilizing chemicals per unit of filter wet solids. Results clearly indicate that substantially less stabilizing chemicals are needed to comply with BDAT requirements. Optimization work is underway now to determine minimum stabilizing chemicals required for BDAT level stabilization.

(2) Stabilization resulted in a 15 percent increase in the volume of the solids.

187

Historically, the problem has been that the physical characteristics of oily waste sludges could not be tamed sufficiently to permit their reliable processing in such simplified extraction processing equipment. The NKD process sufficiently alters the physical characteristics of oily vPaste sludges to tame them and thereby make possible their extraction processing in counter-current, liquid-liquid extraction equipment.

Results of pilot scale testing of liquid-liquid extraction equipment for the processing of oily waste sludges in the NKD process have been extremely satisfying. Although variations in solids loadings have been extremely high, both between sludge feedstocks and between batches of similar feedstock, extractive processing in the pilot scale extraction column has been consistently effective. This is evidenced by two patterns in particular. First, visual evidence confirms that solids present in the sludge act mechanically like a liquid, thereby making and preserving the effectiveness of the liquid-liquid extraction design. Second, available chromatographic data illustrated by the data in Figures 3 and 4 show that essentially no residual hydrocarbons are present on the solids leaving the bottom of the liquid-liquid extraction column. Figure 3 shows the amount and distribution of organics present on API separator solids before and after pilot scale extraction processing. Figure 4 show similar infarmation for the case of pilot scale processing of slop oil sludge. In both cases, virtually no detectable organics remain on the solids produced from the pilot scale liquid-liquid extraction column.

NKD has now processed oily waste sludges solids contents ranging from about 5 wt% to about 35 wt% all without mechanical problems. Total feed rates to the pilot scale liquid-liquid extraction column have ranged from 4 gph to about 20 gph. On a volume flow basis, solvent to feed ratios have ranged from about 3:l to about 1:l. Throughout this range, solids carryover in the extract phase has been minimal. For example, solids carryover in the extract (solvent plus oil) leaving the extractor was 347 ppm during a pilot scale run involving the treatment of API separator sludge at a solvent to feed ratio of 2 to 1 and a total column flowrate of 10 gph. This solids carryover represented about 0.7 wt% of the solids flow into the extraction column.

Solids carried over in the extract leaving the extraction column are highly I

amenable to removal and recycle to the feed. This would be accomplished by employing a simple hydrocyclone on the extract leaving the extractor with recycle of the hydrocycloned solids to the feed. Buildup of fines in this circuit is not expected; however, this will be verified in pilot plant operations later this year.

Pilot Scale Sv - stem for Dewaterina of Extracted So lid3

The raffinate leaving the liquid-liquid extractor contains a mixture of solids, water and entrained residual solvent. Pilot scale testing demonstrates that residual solvent can be readily stripped from the solids/water mixture. To date, this has been accomplished simply by heating the raffinate leaving the extractor to about 200°F and

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FIGURE 3 ORGANICS CONTENT O f API SLUDGE

TREATED IN NKD PROCESS PILOT PLANT

Note: level of quantifiable detection is 1 ppm.

Dilution Factor = 7.5

(a) Raw API Separator Sludge Feed to Pilot Plant

Dilution Factor = 1.

(b) API Separator Solids Leaving NKD Process Pilot Plant

189

FIGURE 4

ORGANICS CONTENT OF SLOP SLUDGE TREATED IN NKD PROCESS PILOT PLANT

Note: level of auantifiable detection is 1 mm.

Dilution Factor = 4

(a) Raw Slop Sludge Feed to Pilot Plant

Dilution Factor = 1

(b) Slop Sludge Solids Leaving The Pilot Plant

190

stirring the mixture to encourage the volatilization of residual solvent. The solids/water mixture leaving this form of processing contains only about 100 ppm of residual solvent. Such results are not surprising since the refinery-based process solvent chosen for the NKD process has a low boiling point and a low heat of vaporization; both properties contribute to insuring the simplicity and reliability of any form of stripping operation. For this reason, certain variations on the present pilot scale residual solvent stripping system may be considered for the commercial process.

Test results to date indicate that any one of a variety of dewatering systems can be effective for the dewatering of solvent stripped extractor raff inate (solids/water). Refiners routinely cope with the problems of oily sludge filtration in their operation of filter presses for volume reduction of raw sludge. The physical properties of NKD processed API separator solids/water mixture are significantly different than those of the original raw API separator sludge. Data presented in Table 3 are intended to highlight the contrast in filtering rates between raw and NKD process treated API separator sludge. Dewatering of NKD processed solids/water takes about 1 /20th percent of the time required for dewatering of raw API separator sludge. Resulting filter cakes are also dramatically different: the moisture content of NKD processed solids is 45 wt % while the moisture content of raw API separator filter cake is still 70 wt%. For reference purposes, Table 3 also displays comparable dewatering data for a mixture of clay and water. While more rapid than the raw API separator sludge, dewatering rates for the clay-water mixture are more than a factor of 10 higher than those for raw API sludge than they are to those NKD processed solids/water.

NKD is currently taking delivery of one type of pilot scale filtering equipment which will be integrated into the existing pilot plant. Additional types of filtering will be tested at vendor laboratories on samples of raffinate generated in the pilot plant.

Pilot Scale Svstem for Recovery of Oil

Pilot scale fractional distillation confirms that product oil can be readily separated from solvent. Heat duties for the distillation are relatively small (1.5 to 2.5 MMBTU/hr depending among other things on degree of heat integration employed). Recovered oil is essentially free of solids and presumably would be recycled back to the refinery crude unit.

Available true boiling point curves of the recovered oils (See Figure 2) suggest that a certain fraction of the recovered oil may boil below the boiling point of the solvent. This behavior must be taken into account in the design of the distillation system to avoid the buildup of undesirable components in the recycled process solvent.

Use of refinery solvent and existing refinery distillation systems would eliminate the need for separate distillation equipment as a part of the NKD process. In such a case, refinery solvent would be delivered to the NKD process plant and oil-laden

TABLE 3

FILTRATION RATES FOR API SEPARATOR SOLIDS

Samnle

Raw API Separator Sludge

NKD Processed API Separator Solids

Clay in Water

(1) 400 gram samples (2) (3) Filtration through vacuum

No. 40 Whatman filter paper

drawn Buchner funnel

% Water Initial Final

81 % 70%

70% 45%

91% 27%

Filterina Time

35 Minutes

1 1/2 Minutes

20 Minutes

192

refinery solvent would be taken from the NKD process plant for distillation processing in one of several possible sections of the refinery.

COMMERCIAL CONSIDERATIONS

The following remarks regarding commercial considerations are provided in light of the extreme pressure the refining industry is facing with the upcoming November 8, 1990 schedule for EPA's implementation of the landban.

Cradle-to-Grave Consideration of costs

In establishing the scope of design basis for its NKD process, NKD addressed virtually all significant elements of cost that arise from "cradle-to-grave" in the handling and disposition of raw refinery oily waste sludges:

0 Pretreatment of Raw Oily Waste Sludges

0 Capital: Amortization and Maintenance

. Manpower and Chemicals

0 Utilities: Steam and Electricity

0 Stabilization of Solids

0 Disposal of Stabilized Solids

Credit for Recovered Oil

Projections of NKD process cost therefore include allocations for all of the above elements. Furthermore, NKD has chosen the weight of raw sludge as its basis for normalizing NKD process costs to a cost per ton basis.

NKD believes that the above methods avoid any confusion regarding either (a) the scope of costs addressed or (b) which "ton" is being discussed.

193

Proiected Cos ts for NKD Process

At the outset of its developmeht work, NKD set a target cost for its NKD process of $300 per ton of raw sludge. Process design decisions (e.g., equipment selection, solvent selection) were made consistent with this cost target, As the pilot scale testing phase of the commercialization program for the NKD process nears completion, the target for costs of $300 per ton continues to look achievable.

The next updating of projections of NKD process costs will occur at the completion of the current pilot scale testing phase of the commercialization program. This is expected to occur at the end of the 1990. ~

Proiected Commercialization Scop e and Schedule

At this point, NKD expects to complete itS pilot scale testing work by the end of 1990. At that point, sufficient process definition will exist to support detailed design, procurement, and construction of a commercial demonstration plant. NKD’s sister division, ENSR Environmental Systems, will be responsible for implementation of the commercial demonstration program. It will also be responsible for performing the commercial business of selling and delivering NKD process plants to refinery customers.

NKD presently hopes to maintain the following schedule for execution of the commercial demonstration program:

1st Quarter 1991 Detailed design of first commercial NKD process plant.

2nd Quarter 1991 Procurement and initiation of construction of first commercial plant.

3rd Quarter 1991 Completion of construction, startup of first commercial plant.

4th Quarter 1991 Shakedown and demonstration operation of first commercial plant.

If this schedule can be maintained, it would establish a first availability of commercial plants for purchase by the end of calendar year 1991.

NKD Process -Based Petitions for Extension of DBAT Compliance Deadline

NKD has had good experience with the filing and granting of petitions with the EPA for extension of established EPA compliance deadlines in conjunction with the commercialization of innovative waste treatment technology.' NKD believes that the NKD process is sufficiently developedlproven to serve as a basis for the filing of one or more petitions for extension of the current deadline of November 8, 1990 for individual refinery compliance with the EPA ban on the land disposal of refinery oily wastes.

According to 40 CFR 268.5, the applicant for an extension of the compliance schedule must demonstrate the following:

He has made a good-faith effort to locate and contract with treatment, recovery, or disposal facilities nationwide to manage his waste in accordance with the effective date of the applicable restriction established under Subpart C of this Part;

He has entered into a binding contractual commitment to construct or otherwise provide alternative treatment, recovery, (e.g., recycling), or disposal capacity that meets the treatment standards specified in Subpart D or, where treatment standards have not been specified, such treatment, recovery, or disposal capacity is protective of human health and the environment.

Due to circumstances beyond the applicant's control, such alternhtive capacity cannot reasonably be made available by the applicable effective date. This demonstration may include a showing that the technical and practical difficulties associated with providing the alternative capacity will result in the capacity not being available by the applicable effective date;

The capacity being constructed or otherwise provided by the applicant will be sufficient to manage the entire quantity of waste that is the subject of the application;

He provides a detailed schedule for obtaining required operating and construction permits or an outline of how and when alternative capacity will be available;

"USX Corporation, in concert with NKD, applied for and was awarded a time extension on its BAT compliance schedule for coke plant wastewaters based upon commitments made for commercial demonstration of NKD's Nite/Denite'" process. At the time, the Nite/Denite'" process had not yet been commercially demonstrated.

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(6) He has arranged for adequate capacity to manage his waste during an extension and has documented in the application .the location of all sites at which the waste Will be managed; and

(7) Any waste managed in a surface impoundment or landfill during the extension period will meet the requirements of paragraph (h)(2) of this section.

A key to a successful petition for extension is a willingness on the part of the applicant to enter into a binding contractual commitment fm the purchase, installation and use of an NKD process plant. To protect both ENSR Environmental Systems and the applicant, any such binding contractual commitment would have to be conditioned upon accomplishment of a number of milestones, among them:

(1) Successful completion of the pilot-scale test program

(2) Successful completion of the commercial demonstration program

(3) Treatability studies which demonstrate the effectiveness of the NKD process on applicant’s specific oily wastes

(4) Commercial terms and conditions acceptable to the applicant for the purchase of commercially demonstrated NKD process equipment.

ENSR Environmental Systems is interested in working with individual refiners to develop a suitable basis for their preparation and filing of petitions for extension of their current compliance deadline for the landban on refinery oily wastes.