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Developing a turnkey nonwovens spunbond line.

the importance of equipment, materials, training and maintenance must be stressed; many different sub systems comprise a spunbond facility

This concludes our series on starting up a spunbond nonwovens line. The final part of the article covers developing, engineering and building the production machine and facility and training, start up and maintenance. Parts 1 and 2 appeared in the January and February issues of NONWOVENS INDUSTRY.

This phase of the project is where the real fun begins. The process and production requirements have been determined and it is now time to begin the design phase of the project.

During this period ABC will rely on feedback from the process engineers to guide its engineering team in the proper selection of equipment and materials for the machine.

For this project we will operate under the assumption that the machine will be comprised of two banks, three meters wide, with a web speed of 400 feet per minute. There will be allowances for chemical post treatment with drying occurring prior to winding the material.

While the design is occuring, there will be several disciplines called upon to help expedite the project. These various groups will work concurrently and will communicate ideas and concerns as the project progresses. For this section we will assume that a site has already been determined.

The rule of thumb when estimating the engineering costs is that an additional 10-15% of the total equipment and facility costs must be set aside. For those companies that are considering projects of this type or are looking to other areas within the nonwovens industry, the 10% figure is accurate.

The intent of this section is to show the different sub-systems that comprise a spunbond machine and the efforts that are required prior to building the facility. In this passage we will concentrate our efforts on the machine portion of the design with brief reference to those other areas that will be part of the project.

Engineering Disciplines To Be Used

Not all facilities need to be pretty. What is desired is that the plant be functional, well planned, maintainable and meet the production requirements for the plant.

The personnel to be utilized on the engineering consultant's staff must have design, construction and start-up experience. This project will necessitate the skills of individuals versed in the following categories:

* architecture

* civil engineering

* structural engineering

* electrical engineering and design

* mechanical engineering and design, specifically:

-pellet handling

-web handling

-calendering

-chemical handling

-drying and steam/boiler

-extrusion, fiber formation emphasis

-piping

* HVAC engineering with process air experience.

Where To Begin

To form an understanding of the scope of the project, perhaps the best place to start is to list those systems that will enable the machine to run. This listing of equipment and/or areas will enable the design team to begin generating the Process Flow Diagrams (PFD's).

For those that are unfamiliar with the equipment, a brief description of the function of each sub-system is included.

1. Pellet handling system. Used to provide the extruders with dry polymer pellets of proper chemical composition. The system must have the ability to add color and additives as well as mix the materials in the proper amounts for blending purposes.

2. Extrusion system. Used to supply fibers consistently and uniformly across the web.

3. Compressed air system. Used to supply air at a variable velocity, flow, pressure and temperature to the fiber forming section.

4. Web former (collector). Used to collect and convey spunbond fibers. Also used to combine the material prior to thermal bonding by the calender. In addition, it holds down the fabric, houses the vacuum forming (under wire exhaust) and edges hold down air when required.

5. Under wire vacuum system and auxiliaries. Used to supply a path to remove the air delivered by the compressed air system and to help mat formation on the web. Also used to provide a means by which the fabric may be held down during the process.

6. Calender system. Used to imprint a pattern onto the sheet and/or thermally bond/melt the material.

7. Post chemical treatment. Used to deliver a chemical treatment to the web for specialty applications.

8. Drying section. Used to dry the web prior to winding on the parent roll.

9. Winding system. Used to wind up the material from the web former after the drying section.

10. Core removal and prep area. Used to remove the steel core from the wound roll for reuse at the winder. The system will also upend the finished rolls and wrap the rolls with stretch wrap.

11. Pack cleaning and support. Used to provide an area for pack breakdown, cleaning, inspection and reassembly.

12. Trim removal system. Used to remove trim during the slitting at the winder. The unit will dump the trim into a baling unit for waste removal.

13. Mount hope rolls as required. Used to spread the web and eliminate wrinkles in the sheet.

14. Coordinated drives system. Used to provide constant tension/draw on the web without breaking the formed fabric.

As part of the overall scheme, the following elements of the system must also be considered, although they do not come under the classification of process machinery.

15. Programmable logic controller and interfaces. Used to provide uniform and simple digital control of the process.

16. Distributed control system and interfaces. Used to provide uniform control and monitoring of the process, provides operators with visual data to control the system. The operation of the DCS must allow for complete control of the process but be simple enough for an operator of minimal education to understand.

17. 480 VAC motor control centers. Used to provide 480 VAC three phase power to all motors, control panels and SCR's in the system.

18. 4160 VAC switchgear (substations). Used to provide 4160 VAC three phase power to all compressor motors and 480 VAC power to the MCC's

Finally, we must regard those areas that do have an impact and are part of the plant operations areas and equipment.

19. Mill-wide HVAC.

20. Mill-wide lighting & power distribution.

21. Operational areas to include:

A. process area

B. utilities/boiler

C. raw material storage and support

D. warehouse

E. maintenance area and stores

F. lab area

G. office and engineering

H. operator/control room.

The purpose of the equipment list was to define the minimum requirements of the system. From this initial directory our engineering consulting team will:

* Develop the Process Flow Diagrams (PFD). The purpose of the PFD is to allow the engineering and management teams to visualize the interaction of the equipment as a total system. The relationships of the equipment will be established and the integration of the control scheme will begin to take form.

* The Electrical and Instrumentation Group (E&I) will define the Process & Instrumentation Diagrams (P&ID's) from the PFD's. The P&ID's are drawings that show not only the process information (air flow rates, pressure and temperature), but also the detailed block control scheme for coordinating the equipment.

* Write and develop the equipment, instrument and control specifications using the PFD's and P&ID's. These specifications, written with the help of the process consulting team, will enable the correct purchasing of the equipment. Once the specifications are written, then the engineering group can proceed with the total machine design.

* Accurately gauge the size and character of the operational areas so as to begin the building/facility arrangement.

* Assign capital equipment numbers to those anticipated purchased items.

* Release, for bidding purposes, the major capital equipment to be purchased.

* Examine environmental concerns and issues and submit recommendations for corrective action, if necessary.

* Request and obtain all necessary permits that concern the equipment.

Initiating The Building Design

The facility engineering portion of this project will be the easiest portion to execute. The building design will be started while the specifications are being written.

All drawings are submitted in a Computer Aided Design (CAD) format. Once the building floor plans have been completed, these background drawings will be given to the mechanical group for process equipment layouts.

The civil engineer will need to be aware of special foundation configurations when applying his skills. Equipment that may need special support include the calender, extruder and drying section. The drawings will be certified by a registered professional engineer prior to releasing the blueprints for construction.

The logistics of building a facility and installing the equipment, on time and under budget, is very complicated. The consulting engineers, as part of their services, will have created a schedule by which the building, delivery, installation and start-up/checkout phases have been coordinated. This schedule will be reviewed by the owner's management team and the engineering group.

The schedule will now drive all efforts leading up to the production of material. If there is slippage at any point on this agenda, then all activities ahead of that point will be pushed back. This lapse, if not corrected, may delay the start-up of the unit.

Another area to consider is the delivery and storage of equipment. Depending upon the delivery schedules of the equipment to be purchased and the progress on the erection of the building, arrangements may be needed to store this equipment off-site.

It is good policy to hold the equipment suppliers to the promised delivery dates. As a general rule, delivery dates a month before they are really needed should be assigned. This will allow for some slippage by the equipment vendor. Whether off-site or on-site storage for equipment is used, an inventory listing of all supplies and equipment is needed.

During the construction phase of the project several groups of individuals will need to be formed to expedite, guide and control the execution of the work. The team's responsibilities and tasks will be construction management, purchasing/expediting and engineering support.

The construction management group will be responsible for the execution of the schedule. They will coordinate all activities at the site and resolve all construction issues. This group will report directly to the owners' management staff and will notify management as to any difficulties.

The purchasing/expediting team will be responsible for the purchasing of supplies and material to the site. They will also prod the equipment vendors about the delivery schedules of the capital equipment.

The owner's representative will be responsible for auditing all materials purchased for the site. This will assure that those items purchased by the general contractor are indeed for the project. It is also a good idea that another of the owner's individuals be in charge of the stores. This will limit the outflow of materials from the site.

Finally, the engineering support team will inspect, assist and determine if the plans are being followed. This group will perform daily inspections and generate weekly reports for review.

This team will constantly change its composition. At the beginning the team may be comprised of structural, architectural and civil engineers. As the project advances these individuals will then be replaced by electrical, mechanical and HVAC engineers. They will also be responsible for the start-up and checkout of the production line.

Training, Start-up And Maintenance

The final phase of the project will concentrate on developing the talents of the employees who will be hired to operate and maintain the machine. The instruction provided must be accurate and concise.

The operations and maintenance teams (O&MT) should be hired and on site at least one month prior to commencing the engineering checkouts. In some instances we will desire to have some of the key maintenance personnel available earlier.

The purpose of training is to have the operators familiar with the process and equipment prior to running product. For a new system, such as the spunbond machine, the training would be split into several phases. These areas include classroom training, inspection and familiarization of the machine, start-up assistance and process trails/pre-production phase.

Start-up And Checking It Out

The start-up of the machine will coordinate all of the different engineering disciplines used on this project. The purpose of the start-up is to prove the concept of the machine and to correct problems in the design before production is begun. Start-up occurs in three phases--construction checkout, engineering checkout and process checkout.

Each one of these areas accomplishes work that confirms the design. In some cases these areas will overlap each other. A well executed checkout will consist of a capable checkout team working with predefined written documentation that governs the course of the checkout.

The construction checkout (CCO) will be conducted by the engineering consultant and members of the owner's staff. The construction checkout will verify that the installation of the equipment, wiring and other items are physically correct.

The CCO will verify that the line is built according to the blueprints. During the CCO corrective action will be taken on those items that will greatly impact the performance of the machine.

The engineering checkout (ECO) will be accomplished by the same team members, but with the addition of the operations staff. The ECO will verify that the machine performs as designed. Primary goals of the ECO are:

* Confirm all communications between the instrument/control and the PLC/DCS.

* Verify that the mechanical operation of the individual components is correct.

* Begin preliminary process checks to verify the operation of all of the components as an integrated system.

During the ECO, corrective action will be limited to minor changes in the design.

The process checkout (PCO) will be performed by the operations staff and the process consultant. The engineering consulting team should be removed from the site and used for information only. The PCO will improve upon the process and will serve to train the operators in the correct utilization of the machine.

During the PCO corrective action will be limited to minor changes in the design and changes to the process variables.

The Role of Maintenance

The maintenance team will require special attention during the training phases. Though the team may be well versed and familiar with the types of equipment purchased, it may not be familiar with the specific manufacturer of that equipment.

It is important that the equipment vendors and manufacturers conduct training classes in-house on their products. The idea of maintenance specialty training will help to maintain machine uptime.

Mr. Harmon is a senior partner at HSJ Group, Alpharetta, GA. He had been previously employed with Johnson & Johnson and Dow Chemical. HSJ Group is an engineering consulting firm specializing in the nonwovens business.
COPYRIGHT 1992 Rodman Publications, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1992 Gale, Cengage Learning. All rights reserved.

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Title Annotation:Nonwovens Technology; part 3
Author:Harmon, Jerry
Publication:Nonwovens Industry
Date:Mar 1, 1992
Words:2406
Previous Article:The top end product manufacturers.
Next Article:Historic needlepunch developments.
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