FINAL REPORT FOR P2 PROJECT IN COLLABORATION WITH L.W. PACKARD & CO., INC.

Project Title: Replacement of the Tar Remover from the Wet Finishing of Woolen Fabric.

Project Participants:

Volen R. Nikolov (subcontractor)

Department of Chemical Engineering

University of New Hampshire Kingsbury Hall, 33 College Road

Durham, New Hampshire 03824-3591

e_mail:

Douglas Abbott (subcontractor)

Department of Chemical Engineering

University of New Hampshire Kingsbury Hall, 33 College Road

Durham, New Hampshire 03824-3591

e_mail:

Submitted to:Ihab H. Farag (supervisor of the project)

Department of Chemical Engineering

University of New Hampshire

Kingsbury Hall, 33 College Road

Durham, New Hampshire 03824-3591

Phone: 603-862-2313, Fax: 603-862-7649

e_mail:

Copy to:Ms. Susan Francesco, Vice President

L.W. Packard and Company, Inc.

Ashland, NH, 03217

Phone: 603-968-3351, Fax: 603-968-7649

Executive Summary: This project involved the search for a more environmentally friendly and safer process for the removal of tar while still maintaining the quality of the wool fabric. “Tar” is a collective name for all the different kinds of paint and dye which the farmers use for identification of the fleece. The tar remover currently used by L.W. Packard & Co., Inc. is 90% volatile and contributes high COD and BOD loading to the Town of Ashland POTW.

Background:

Tar removers have been used in the textile industry for many years. They usually contain VOC’s as light aromatic naphtha, benzene, toluene, xylene, and similar solvent based products. Tar removers are necessary to remove the fleece identification products from the fabric. Tar removers also assist in the fulling process. The second use can be overcome with currently available machinery and “greener” solvents.

L.W. Packard & Co., Inc. has been able to eliminate the use of tar removers on all fabrics except those scheduled to be processed into light shades. If a set of light shaded cloth is processed without the use of the tar remover colored specs of tar will be noticed on the fabric. This makes the set unacceptable for the customer and cannot be sold.

While tar removers are necessary, they’re use is a large source of VOC emissions. They contribute high BOD and COD in the effluent stream, which increases L.W. Packard’s loading to the POTW.

Tar removers are substances of fire and health hazard. Tar removers are combustible liquids, they are irritating to skin, which may cause dermatitis. The vapors might be irritating to nose, throat and respiratory tract. Exposure to high vapor concentration may cause depression. Chronic exposure labeled as moderate Central Nervous System Depression (CNSB) may be evidenced by giddiness, headaches, dizziness, and nausea.

The textile industry and L.W. Packard has been working toward elimination of tar removers for years with extremely limited success. L.W. Packard administration claims that historically many chemical salespeople have passed through their doors with the miracle chemical cure, but thus far there has been no success. When this substantial textile problem is solved, it will help all of the woolen textile companies.

Objectives:

1.) To review current environmentally friendly tar removers.

2.) Reduce the BOD and COD loading to the POTW.

3.) Investigate possible separation processes for reuse of tar remover.

4.) Reduce effluent waste from fulling process.

5.) Ideally, eliminate the use of the tar remover.

Approach/methodology:

We started by drawing a flow sheet on the fulling process (figure 1). Next, we contacted various chemical vendors as well as three manufacturers: Synthetic Labs, Boehme Filatex, and Rhone Poulenc. Meetings with sales representatives were very helpful in assessing the problem. An attempt was made to approach the problem from nontraditional standpoint of view using the software product “Solvent Alternatives Guide” (Version 2.0).

In order to determine what chemicals were going to be effective, bench scale testing was done at the University of New Hampshire. During this time, nine different chemicals were examined. We treated tarred samples of cloth with the samples tar removers for an extended period of time to determine their dissolving efficiency. The currently used tar remover (Tar Remover ACF), from Synthetic Labs, was shown to be extremely efficient in comparison to the majority of the sample tar removers. For all but three of the tar removers in full strength (without any dilution) there was no evidence of dissolving of the brown tar spots. To date the samples are still exposed to the action of the tar removers. Tar Remover 60 and Tar Remover 200, manufactured by Synthetic Labs, and Texclean-TR, manufactured by Chute Chemical Co., proved to be the best replacements.

As a part of the bench testing work, we designed and manufactured an apparatus (presented in figure 1) to spray the tar removers evenly over the samples of wool. The idea was to maintain the same (volume of tar remover)/(area of cloth ratio) as in the full scale process. The apparatus consisted of an acrylic tube 1.5” in diameter, with one end capped. A 0.1mm diameter compressed air nozzle was mounted axially in the cap. Perpendicular to it a 5mm orifice was drilled to enable the introducing of defined volume of tar remover by a pipette tip. The amount of tar remover injected was equivalent to (1 gallon tar remover)/(piece 100 yards long and 2 yards wide). As the tar remover was expunged from the pipette, the air sprayed the chemical evenly on the cloth (see figure 1). The tarred samples were then rubbed by hand to imitate the fulling process, and then treated with soap solution and water. Boehme Filatex, Inc., are still developing a product as of this writing.

The possible reuse of the tar remover using membrane technology was also investigated. A list of possible companies that specialize in oil/water separation was made. A proposal from Dynatech Systems, Inc. was received, and a sample of the effluent from the fulling process was sent. We are still awaiting word of success from the company.

Tarred sample piece of cloth tightened

with an elastic band

FIGURE 2

Chemical usage/equipment needs:

Bench scale testing at UNH was done under a hood. The chemicals involved were the nine samples ordered from the various companies. We also utilized COD (chemical oxygen demand) machinery at the Town of Ashland POTW.

Releases/Wastes generated by the facility:

L.W. Packard is generating waste stream with a low pH value, containing dye from the rinse operations in the dyehouse as well as naphtha, cumene, methylbenzne, and xylenes from the fulling and tar removal operations. The pH value is being corrected in the discharge tank of L.W. Packard (alias “the Swamp”). After this adjustment, phosphoric acid is added, and the wastewater is discharged to the local POTW of Ashland. The phosphorous source is necessary for the normal growth of dye biodegrading bacteria, which are added at the POTW. The latter results in additional treatment costs.

Work accomplished:

We started by observing the fulling process and conditions, followed by a flow chart of the entire process (Figure 2). Next, we researched and contacted several chemical manufacturers and vendors for a list of possible chemical alternatives. These companies are compiled in Table 1.

Observation and study of the fulling process:

1. Dispensing tank to drain

2. To dispensing tank

3. To drain

4. To main tank

5. Main tank drain

Figure 2: Schematic of a fulling mill.

The consecutive steps in the fulling cycle are:

  • Charging the mill with cloth. Presetting the digital meters for the tar remover and soap, and adding the necessary amount of the both substances.
  • Fulling until the necessary dimensions are reached.
  • Rinsing 6 minutes with a open drain to the swamp.
  • Filling the mill with water. The necessary amount of water is filled in 6minutes. During that time the outlets to the swamp are closed.
  • Souring 6 minutes. At that time water is not leaving or entering the mill.

Final rinse in 6 minutes. The outlet to the swamp is open during that time.

After the companies were contacted, samples were sent to L.W. Packard & Co., Inc. for bench scale testing at the University of New Hampshire. We received a total of nine (9) samples of possible replacements. We identified two possible alternatives: Tar Remover 60, an OXO-hexyl-acetate containing no methylbenzene or xylene, and Texclean-TR, made using aliphatic naphtha. Upon further review, the Tar Remover 60 was chosen for the following reasons:

1.) Tar Remover 60 contains a more aggressive solvent and detergent system than the Tar Remover ACF (product presently used). It is made using an acetate ester derived from a C6 Alcohol as the solvent.

2.) Because of the increased effectiveness, the use volume is estimated to be 60% less than Tar Remover ACF

3.) Greater wetting abilities

4.) Reduce surface tensions of emulsions.

5.) Oxygenated solvent giving enhanced biodegradability over a hydrocarbon solvent.

6.) Contains no benzene, ethylbenzene, naphthalene, trimethylbenzene, or xylene.

Because of time constraints, we only had time to run the Tar Remover 60 in the full scale process. For the full scale test, three 10 yard samples of cloth known to be contaminated with tar were tacked to the end of four pieces of cloth, also known to be contaminated with tar. 2.5 gallons of TR 60 was used, and removed all tar spots from all four pieces. In a normal run, 4 gallons of TR ACF would have been used. Therefore, for an eight piece fulling mill, 5.0 gallons of TR 60 versus 8.0 gallons of TR ACF would be used, a 3.0 gallon difference. This results in significant source reduction and an immediate decrease in solvent effluent.

An investigation into the possible reuse of the tar remover was also made. Waste from the fulling operation was sent to Dynatech, Inc., a company specializing in membrane separation technology. It was determined that ultra-filtration would be efficient enough to separate the water-solvent emulsion. After Dynatech performed pilot scale testing at their New Jersey facility, the product was than sent back to L.W. Packard. It was determined that the tar remover could indeed be reused by membrane technology. Coupled with the use of TR 60, this would effectively eliminate BOD and COD loading from the fulling operation to the POTW.

Project Benefits:

Benefits to L.W. Packard include an immediate decrease in effluent from the fulling operation which results in reduced COD and BOD loading to the Ashland POTW. Furthermore, in the event that membrane technology is implemented in the plant, the tar remover can be reused which would effectively eliminate BOD and COD loading from the fulling operation.

Pollution Prevention Measures Applied:

Although many P2 measures were applied during the course of the project, source reduction and reuse of the tar remover were most prevalent in our approach.

REFERENCES

Ms. Susan Francesco, Vice President- Safety, L.W. Packard & Co. Inc.- Provided detailed descriptions of the fulling process and sources for literature search.

Mr. Edward F. Hosmer, Synthetic Labs, Inc.- Provided valuable advice on how to go about solving the problem, as well as in-depth chemical literature about various products.

Development of a Pollution Prevention factors methodology based on life-cycle assessment. vii, 27 p. c. 1994, Microform.

Gaddis, J.L. Evaluation of hyperfiltration for Separation of Toxic Substances in Textile Process Water. Microfilm, Research Triangle Park, NC. 1979.

Jurbiel, Jerzy. Removal of Color, Detergents, and other Refractory Substances from Textile Wastewater. Microfilm, Research Triangle Park, NC. 1978.

Licis, Ivers J. Industrial Pollution Prevention Opportunities for the 1990’s. U.S. Environmental Protection Agency, Government Document, 1992.