Addressing Salt Issues in Textile Dyeing Using an ISQ and ARIZ

by: Darren Heath
TE589A
North Carolina State University
 
Under the direction of:
 
Dr. Michael S. Slocum
Chief Scientist / Engineer
Ontro, Inc.*
(*Adjunct Assistant Professor N.C.S.U.)
 
Dr. Timothy G. Clapp
Professor
N.C.S.U.

Abstract

 

The purpose of this paper is to apply the algorithm of inventive problem solving as well as the Innovative Situation Questionnaire (ISQ)[*] to understand and identify possible generic solutions for the overuse and discharge of salt in textile dyeing.  Salt seemingly needs to be used during this dyeing process, but once the dyeing operation has taken place, a large amount of dissolved salt still exist in the water. This dissolved salt is now considered to be contaminating the water and needs to either be removed or not used at all. A great amount of information was generated during the completion of the ISQ in reference to the usage of salt and the dyeing process. The ARIZ helped to uncover an underlying factor that led to why salt was used in general for the dyeing process. It also aided in providing possible generic solutions to avoid the use of salt in general or other means to generate the same effect as salt does. Within the ARIZ, Substance-Field modeling and Many Little People Modeling was used along with other tools contained in the ARIZ. Many generic solutions were identified but no specific solution was generated.

Background

In a typical batch or vat dyeing operation for textiles, a reservoir is filled with water along with color dyeing molecules and pieces of textile cloth. In order for the dye to fully penetrate the cloth and provide the necessary dyeing action, large amounts of salt are added to the bath. For this, a typical dyeing plant can easily consume approximately 50,100 pounds of salt a day[†] which leads to a use of approximately 15,000,000 pounds of salt a year. This could cost a dyeing plant approximately $750,000.00 a year[‡] when buying this much salt to accomplish dyeing at the plant. To better illustrate the concept of how the dye molecules, water, cloth and salt interact with one another in the reservoir, a simple sketch of the water molecules, cloth and dye molecules together [Figure 1] is below.

 

Discussion

As one can see, the water molecules tend to attach themselves to the dye molecule as well as attaching themselves to the cloth. Also, many molecules of water exist between the dye molecule and the cloth. By using the operational zone identification, one can see where the useful operating zone (UFOZ) and the harmful operating zone exists (HFOZ). The zones also help to identify when the useful operational time and (UFOT) harmful operational time (HFOT) occur. [Figure 2].


Figure 2: Operational zone depiction

UFOZ Contains the space or contact zone between the dye molecule and the cloth to produce dyeing
HFOZ Contains the space between the dye molecule and the cloth itself consisting of water molecules
UFOZ/HFOZ Overlaps each other at the point of contact between the dye molecule and the cloth

 

Using this operational zone identification, a Many Little People (MLP) model could be applied to aid in understanding the process and what needs to actually occur on the molecular level during the dyeing process. This can be seen below [Figure 3,4].

One can see that the little people between the cloth and the dye molecule move out of the way as well as the little people holding onto the dye molecule and the cloth let go. It was thought that there might be a way to use the movement of the little people to actually push the dye molecule towards the cloth to facilitate dyeing.

Substance Field (Su-Field) modeling also proved to be of use when completing the ARIZ. The initial Su-Field model is represented in Figure 5. One can see that by merely placing the cloth in the water along with the dye molecules that there is an insufficient action between the two. The dye molecules do not effectively migrate to the cloth.


Figure 5: Primary Su-Field model.

In order to complete this Su-Field model, it appears that a force needs to be added [Figure 6]. The Force that is added is the ionizing of the water.

To get the force F1, two other substances needs to be added, the salt and the water. With these two substances added, a second force, F2, needs to be added which is the chemically dissolving of the salt in the water. When combined, these two additional substances produce this ionizing effect, yet after the dyeing operation, the salt contaminates the water [Figure 7].

Figure 7: Completed secondary Su-Field model.

It can be seen that a contradiction is occurring within the model and needs to be addressed. By using contradiction matrix theory and the separation principles, the contradiction can be resolved. This contradiction can be seen as a Key Knot and a Reverse Key Knot [Figure 8,9].

 

 

Generic Solutions

Below are a listing of just a few of the generic solutions derived by the use of the ISQ as well as the ARIZ. A comprehensive listing of generic solutions can be found in Appendix A and Appendix B.

Solution Standard 5-1-3 [1], After the substance in the system is not needed any longer, it should disappear or become indistinguishable from the substance that was in the system or in the environment before. E.g. the substance that has been introduced may disappear due to chemical reaction or change of phase.

Group Standard 5-5 [1], substance particle obtaining e.g. ions. 5-5-1, If a substance particles are required to solve the problem, but are not immediately available according to the problems conditions, the required particles are to be obtained by breaking down a substance of a higher structural level.5-5-2, If a substance particles are required to solve the problem, but they cannot be produced directly by breaking down a substance of a higher structural level, the required particles are to be obtained by combining particles of a lower structural level. 5-5-3, When a substance of a higher structural level has to be broken down, the simplest way is to break down the nearest “whole” one and vice versa, when completing or combining particles of a lower level, the simplest is to complete the nearest lower “non-whole” one.

By using the standard solution 1-2-4 [1], which states, If there exist a harmful and useful function between two substances, and direct contact between the two substances must be maintained, the problem can be solved by transition to a dual Su-Field Model (SFM). The useful effect remains with the given field while a new field neutralizes the harmful effect or, converts the harmful effect to a useful one.

 

I.S.Q.

 

1.    Info

1.1       System Name

Salt remover or salt reducing system

1.2       Primary Useful Function

The system separates dissolved salt from water or provides ways to reduce the amount of salt in the water

1.3       Current or Desired System Structure

Pure water, cloth, salt, and dye are placed into a dyeing machine. The salt dissolves into the water and drives the dye out of the water and into the cloth. The cloth is then removed and the water containing the dissolved salt is left behind.

1.4       Functioning of System

The system will separate dissolved salt from water as it passes through a “station x”, or will dye cloth with the minimum amount of salt possible.

1.5       Environment of System

System will be located within or near a textile plant. Other pieces of equipment such as dyeing machines, dryers, color removal systems, boilers, ozoneators, heat recovery systems, storage tanks, warehouses, preparation machines (scouring, bleaching, mercerization), finishing machines (chemical, physical), and logistical support will be in the vicinity of “station x”.

 

Available Resources

Substance Resources

Space Resources

Field Resources

Time Resources

2.    Info in Reference to Problem Situation

2.1       Desired Improvement to System and/or Function to Eliminate

The drawback is that salt contaminates the water. The desired improvement is to recover the salt from the water discharge or to generate dyed cloth with the minimum usage of salt.

2.2 Mechanism that Causes Drawback

Salt has an extremely high affinity for water. All liquids that have higher affinities for salt are miscible with water generating an even more contaminated bath. Without using salt for dyeing cloth, alternative means for dyeing will have to be implemented.

2.3       History of the Problem

Cloth that needed to be dyed required large amounts of salt in the water with the cloth and dye in order to drive the dye into the cloth. It is expensive to purchase large amounts of salt cyclically. Competition between dyeing companies requires the elimination of costly waste as well as costly raw materials. Recovery of the salt or minimization of salt usage would prove economical for the company. It is also toxic to the environment when high levels of salt is discharged into the environment.

2.4       Secondary and/or Tertiary Problems Changing the System

2.5       Allowable Changes to the System

  1. Methods for dyeing do exist which require no salt while using the same cloth, which would be transparent to the customer.

  2. Separate baths that contain salt from the non-salt water coming from other systems therefore being able to treat smaller volumes of water.

  3. Change the cloth to a synthetic fiber, which involves a redesign of the cloth and also involves the customer.

  4. Modify the machine so less salt is required.

  5. Optimize each process so less salt is required such as: the temperature at which the dyeing takes place, the dwell time of the cloth in the dyeing machine, the amount of cloth being added to the dyeing machine, use of a different dye for a particular type of cloth, utilize a different type of dyeing machine.

  6. Recovery of the salt water where the residual dyes are destroyed in the waste dye water to utilize a closed-loop system for re-use of the salt water.

  7. The use of different types of salt, which are non-toxic to the environment and more easily recovered as well as inexpensive, could be used for driving the dye into the cloth.

  8. Select dyes that require less salt to dye the cloth.

  9. Treat all the water instead of segregating water.

2.6       Limitations to Changes in the System
Limitations for changes A}

Limitations for changes B}

Limitations for changes C}

Limitations for changes D}

Limitations for changes E}

Limitations for changes F}

 Note: during this discussion of the limitations to this particular system change, interesting ideas were brought up on how to destroy dyes in the water and possible ways to reclaim salt so the contaminated water could be reused or decontaminated. These were:

The above list contains ideas that should be examined more closely and are possible candidates for generating a solution. Although these ideas contain secondary and possibly tertiary problems such as:

Passing an electro-chemical current through the water produces more salt in the water

Chemical coagulation with the dye produces a high level of precipitate

The use of ozone to destroy the dye produces more water, these could be overcome.

End Note

 Limitations for changes G}

Limitations for changes H}

Limitations for changes I}

 

3          Criteria for Selecting Solution Concepts

3.1 Define Technological Characteristics

3.2  Define Economical Characteristics (Price Ceiling?)

 Yes,Competition between dyeing companies requires the elimination of costly waste as well as costly raw materials. Not only the production cost but diverting budget to implement any idea which would either provide little to no return or gain will almost not be considered.

3.3 Define Timetable (Long/Short Term?)

For the particular industry solutions that would require a long term commitment would also probably not be considered. Yet it appears that secondary administrative contradictions may be present and could possibly be resolved.

3.4 Level of Innovation Desired?

The system needs to be cost effective to build so that within 5 years time the system can pay for itself from the savings gained from not having to buy large quantities of salt or by the reuse of the water containing salt. The time criterion needs to be acceptable in not to hinder to production of the final products or to interrupt the normal flow of the operation as is. A high level of innovation is required to satisfy the problem solver as well as to over come the failed attempts listed below.

4          History of Attempted Solutions

4.3       Previous Attempts

The use of Reverse Osmosis to filter out the salt as well as Electro-dialysis has been explored. Reuse of the salt by refurbishing the salt dye bath by bleaching out the dye, then also evaporation of the water has been explored. Also, other dyeing technologies have been explored.

 

ARIZ

1.0           Mini-Problem Formulation

1.1 The Key Knot

       The problem is having water that contains dissolved salt within it. Salt is necessary to drive dye into cloth during the dyeing process in textiles, but when the dyeing process is complete, the water that is left still is contaminated by the dissolved salt.

1.2 The Useful Function

            The salt (useful function tool) drives dye (useful function product) into cloth during the dyeing process.

1.3 The Harmful Function

            The salt (harmful function tool) contaminates the water (harmful function product) which is left behind after the dyeing process.

1.4 The Common Element

            The salt is the common element.

1.5 The Graphical Scheme of the Conflict

            The salt is the common element.

1.6 Formulate the Functional Initial Contradiction IC-1 corresponding to the Direct Conflict.

            If high amount of salt is used (+) cloth easily absorbs dye but (-) the wastewater is contaminated.

 

1.7 Render the Reverse Key Knot.

1.8 Render the graphical scheme of the Reverse Key Knot.

1.9 Formulate the Functional Initial Contradiction IC-2 corresponding to the Direct Conflict.

            If no salt is used (-) dye does not go into cloth well but (+) the wastewater is not contaminated.

1.10 Formulate the Mini-Problem.

            There is a system for driving dye into cloth (Useful Function) using salt, dye, water, and cloth.

          IC-1 If high amount of salt is used then (+) dye is driven into the cloth but (-) the water is contaminated.

          IC-2 If no salt is used then (+) the water is not contaminated but (-) the cloth is not dyed.

It is essential under minimum changes in the system to (+) dye the cloth and (+) not contaminate the water.

2.0 The Pseudo-Fundamental Contradiction Formulation and Resolving

2.1 Formulate the Pseudo-Fundamental Contradiction (PFC).

Salt (Useful Function) should be big in (in state A1) for sufficient dyeing of the cloth (performing the useful function) and should be low (in state A2) to eliminate contamination of the water (harmful function).

2.2 Try to Resolve the PFC using principles of fundamental contradictions.

It is possible to resolve this contradiction separating contradictory requirements in space.

 

3.0 Conflict Enforcement

3.1 Enforce the conflict for IC-1

Introduce large amounts of salt in the water to highly contaminate the water.

3.2 Enforce the conflict for IC-2

Introduce no salt into water producing non-contaminated water.

How do we dye cloth using no salt? Different dyeing technology?

 

4.0 Formulation Directions for Solutions

4.1 Formulate the model for IC-1

Given that salt, dyeing, and water participate in the conflict.

IC-1: If high salt is added (+) the cloth is dyed but (-) the water becomes contaminated.

It is essential to introduce the “x-resource” which prevents contaminating the water (harmful function) and drives the dye into the cloth (useful function) allowing the cloth to be dyed (performing the useful function).

4.2 Formulate the model for IC-2

Given that salt, dyeing, and water participate in the conflict.

IC-2: If no salt is added (+) the water does not becomes contaminated but (-) dye is not driven into the cloth.

 

It is essential to introduce the “x-resource” which drives the dye into the cloth (performing the useful function) and prevents the water from becoming contaminated (harmful function).

Note: Maybe the salt could be substituted with something else that would equally well or better drive the dye into the cloth.

 

5.0 Using Substance Field (Su-Field) Transformations

5.1 Render the Initial Su-Field Model

Add a field to create a sufficient Su-Field model (F1)

 To complete this Su-Field model another Force has to be added (F2)

Now it appears that there is still a negative effect on the water by the salt. It also appears that ionizing the water by chemically dissolving salt in the water may not be the best way the ionize the water. Looking closer at the top Su-field model containing F2, F1, S2, and S1 and applying the standard solutions for resolving this conflict, an alternate method may be found.

This Su-Field model could also be constructed as:

It appears that by looking at the substance interaction between the salt and water that a contradiction occurs where a useful effect is produced by the salt for ionizing {refer to Group Standard 5-5  [1]} but also a harmful effect exist where after the process the salt is still present in the water. Some considerations on resolving this contradiction can be found using the 76 standard solutions listed in the text by Salamatov or by applying the separation principles.

By using the standard solution 1-2-4 [1], which states, If there exist a harmful and useful function between two substances, and direct contact between the two substances must be maintained, the problem can be solved by transition to a dual Su-Field Model (SFM). The useful effect remains with the given field while a new field neutralizes the harmful effect or, converts the harmful effect to a useful one.

By using the standard solution 2-4-2 [1], which states, That if the efficiency of control of a SMF needs to be enhanced, then the addition of ferromagnetic particles coupled with the use of a magnetic or electromagnetic field for enhanced controllability is a possible solution.

By using the standard solution 2-4-11 [1], if it is difficult to introduce ferromagnetics or to perform magnetization, one should shift to an eSFM using interactions of an external electromagnetic field with currents either fed through a contact or induced without a contact, or using interaction between these currents. Also, if a magnetic fluid cannot be used, one can use an electrorheologic fluid (a suspension of fine quartz powder in toluene, for instance, with the viscosity controlled by the electric field.)

Solution Standard 3-2-1 [1], which states, Efficiency of a system at any stage of its development is enhanced by transition from macrolevel to microlevel: the system or its part is replaced by a substance capable of performing the required action when interacting with a field.

Solution Standard 5-1-1-8 [1], which states, If it is necessary to introduce a substance in the system, but it is forbidden to do so by the problem conditions or it is not allowed by the system’s operation conditions, the substance is introduced in the form of a chemical compound where it is subsequently separated.

Solution Standard 5-1-1-9 [1], which states, If it is necessary to introduce a substance in the system, but it is forbidden to do so by the problem conditions or it is not allowed by the system’s operation conditions, the substance is to be produced by decomposing the external environment or the object itself. E.g. By electrolysis, or by changing the aggregate state of a part of the object or environment.

Solution Standard 5-1-3 [1], After the substance in the system is not needed any longer, it should disappear or become indistinguishable form the substance that was in the system or in the environment before. E.g. the substance that has been introduced may disappear due to chemical reaction or change of phase.

Group Standard 5-5 [1], substance particle obtaining e.g. ions. 5-5-1, If a substance particles are required to solve the problem, but are not immediately available according to the problems conditions, the required particles are to be obtained by breaking down a substance of a higher structural level.5-5-2, If a substance particles are required to solve the problem, but they cannot be produced directly by breaking down a substance of a higher structural level, the required particles are to be obtained by combining particles of a lower structural level. 5-5-3, When a substance of a higher structural level has to be broken down, the simplest way is to break down the nearest “whole” one and vice versa, when completing or combining particles of a lower level, the simplest is to complete the nearest lower “non-whole” one.

6.0 Operational Zone Analysis and Resources Discovering

6.1 Determine the operational zones

UFOZ Contains the space or contact zone between the dye molecule and the cloth to produce dyeing
HFOZ Contains the space between the dye molecule and the cloth itself consisting of water molecules
UFOZ/HFOZ Overlaps each other at the point of contact between the dye molecule and the cloth

 

6.2 Many Little People Modeling

Smart Little Persons holding on to the dye molecule and cloth as well as Smart Little Persons keeping the dye from reaching the cloth all need to move out of the way so the dye molecule can reach the cloth.

 

6.3 Discovered Resources

 

Source

Substance Resource

Field Resource

Operational Zone

 Workpiece

Cloth

Textile Material

Mechanical

Tool

Dye Molecule

Colorant Molecule

Chemical

Medium

Water

Hydrogen/
Oxygen

Chemical

System (Excluding the OZ)

Dyeing System

Dye Machine

Metal

Mechanical/
Chemical

Pipes

Valves

Super System

Neighboring Systems

Dryers

Polymeric absorption Technique

Thermal
Chemical

Color Removal Systems

 

 

Boilers

 

Thermal

Ozoneators

Pure O,O2, and O3

Chemical

Heat Recovery Systems

 

Thermal

Storage Tanks

Metal

 

Preparation Machines

Metal/
Chemicals

Mechanical/
Chemical

Finishing Machines

Metal/
Chemicals

Mechanical/
Chemical

 

7.0 The Initial Ideal Final Result Formulating

7.1 Describe the IIR according to the following scheme

For IC-1 For IC-2
X-Resource X-Resource
Without system complicating Without system complicating
Without harmful consequences Without harmful consequences
Prevents the salt from contaminating the water (harmful function) or recycles the salt water after dyeing or provides an alternative to ionizing the water by breaking the barrier between the dye molecule and the cloth (UFOZ) either during or after dyeing of the cloth (useful function) Decline the use of salt being added to the water during the dyeing process (UFOT) while still allowing the dye to migrate through the water (HFOZ) to the cloth in order to dye the cloth (performing the useful function)  
Maintain the ability of the dye molecule (useful function tool) to reach the cloth to dye the cloth (perform the useful function) during all time that dyeing needs to occur (UFOT) between the dye molecule and the fabric (UFOZ) Prohibit the contamination of the water by the salt (performing the harmful function) while still allowing the cloth to be dyed (performing the useful function)

It would be ideal to have the little people blocking the path between the dye molecule and the cloth to open up and provide an open pathway for the dye molecule to reach the cloth. Also, to have the little people holding onto the water and the cloth to push the dye molecule towards the cloth.

Translating this to technical terms:

It would be ideal for the dye molecule as well as the cloth itself to be ionized in order to provide a mechanism for the dye molecule to be attracted to the cloth without having to add salt to the water to provide the ionizing effect.

7.2 Create the preliminary portrait of the x –resource able to perform all of the requirements included in the IIR

There are special little people that are holding on to the dye molecule that can push it (the dye molecule) towards the cloth. Likewise, there are special little people holding onto the cloth that can push the cloth towards the dye molecule.

Also, there are special little people that can move out from in-between the dye molecule and the cloth in order for the dye to reach the cloth to dye the cloth (performing the useful function).

The x-resource needs to create an ionizing effect between the dye molecules and the cloth in order for them to be attracted to each other and also needs to be able create “tunnels” between the dye molecule and the cloth within the water to provide a pathway for the dye molecule to move.

8.0 Fundamental Contradictions Formualtion

8.1 Formulate the Brief Fundamental Contradiction

The x-resource should exist within the space between the dye molecule and the cloth (HFOZ) at all times during the time in which dyeing is occurring (UFOT). The x-resource should provide the mechanism for allowing the dye molecule (useful function tool) to migrate towards the cloth for dyeing (performing the useful function) satisfying the requirements stated in the IIR and should not contaminate the water after the dyeing process has occurred.

8.2 Formulate the Fundamental Contradiction for the process

The direct process is the application of the dye molecules onto the cloth by opening a pathway for the dye molecules to travel towards the cloth.

The opposite process is that the substance that performs this action stated above should not contaminate the water.

Thus the fundamental contradiction for the process appears like this:

The mechanism for applying dye to the cloth (process) should occur within the (HFOZ) as well as the (UFOZ) during the time which dyeing is occurring (UFOT) yet, the mechanism allowing dye molecules to migrate towards the cloth (performing the useful function) should also not be present in the water after the dying process takes place. 

9.0 Fundamental Contradictions Resolving

9.1 Try to Resolve the Brief Fundamental Contradiction using the resolving Principals

The x-resource should be inside the space between the dye molecule and the cloth but should not be in the space after dyeing occurs.

By changing the weight of the dye molecule, the fabric could possibly be laid flat on the bottom of the dye machine to allow the dye molecule to precipitate out of the water an “fall” onto the fabric.

By changing the area/volume of the dye molecule, the dye molecule could possibly be so large as to easily come into contact with cloth.

By changing the speed at which the dye molecule approaches the cloth it could push the water molecules out of its way as it migrates in the direction of he cloth. The same is true for changing the force it has while it is traveling towards the cloth.

By changing the pressure at which the dye molecule hits the cloth, it could press the water molecules out of the way from in between the dye molecule and the cloth.

By changing the temperature of the water in which the dye molecule resides, the dye molecule could possibly have some much energy that they will come into contact with the cloth rather quickly.

By changing the amount of dye in the water, there could nothing else in the bath but the cloth and the dye itself. This would force the dye molecules to be in intimate contact with the cloth.

By allowing the cloth to be stretched over an opening in the dye machine, gravity could be used to make the dye bath flow downward through the cloth, forcing the dye molecules to come into contact with the cloth as they pass through the cloth.

By taking the salt and water combined, one can use a system of filters to extract the residual dye from the water and “clean up” the wasted water containing the salt to allow the salted water to be reused.

By taking the combined salt and water and passing it through an evaporation stage, one could evaporate the water from the salt bath and deposit salt crystals behind as the water evaporated.

By taking the wasted water containing salt and dye, one could add the right amount of supporting dyes to produce a varying shade of color from the original in performing a different dyeing process of the different shade.

By using a different type of salt, the required properties of the salt could be enhanced to perform the necessary action.

By using a different type of dyeing process the use of salt could be eliminated altogether, and vice versa, a different type of dye could be used to eliminate the use of salt also.

Separation Principles could also be used such as space, time, scale, and upon condition.

With this in mind the salt and water could be separated in space as in the way of injecting the cloth with the salt and not allowing the salt to enter the water.

Or, time by stating that at the time T1of dyeing, the salt needs to be present, but at the time T2 (T2 > T1) the salt needs to be out of the water. This may be possible by precipitating the salt out of the water, absorption of the salt, or by reacting it with another chemical to break it down.

Separation upon condition could be used if a different technique of applying dye to the cloth could be used.

Separation in scale could be applied to the amount of dye within the water, By introducing an extremely large amount of dye into the water compared to the normal amount, the dye would be forced to come in contact with the cloth.

Conclusion

The ISQ and the algorithm for innovative problem solving (ARIZ) utilize many of the same techniques that allow the problem solver to properly identify the problem under consideration. There are areas of each that do not overlap and this makes the problem solving process more complete by utilizing both processes (ISQ and ARIZ). 

 

References:

  1. Dr. Smith, B., Professor North Carolina State University,
    April 22, 1999.

  2. Dr. Terninko, J., Zusman, A., Zlotin, B., Step-by-Step TRIZ Creative Innovative
    Solution Concepts
    ; New Hampshire, 1996.

  3. Salamatov, Y., TRIZ: The Right Solution at the Right Time;
    The Netherlands, 1998

  4. Dr. Slocum, M., Professor North Carolina State University,
    January-May, 1999

  5. Dr. Clapp, T., Professor North Carolina State University,
    January-May, 1999


[*] Ideation International Corporation

[†] Based on a discharge of 2 million gallons of water a day with each gallon of water weighing 8.34 pounds and using 3000 parts per million of salt to water.

[‡] When using an approximate bulk cost of $0.05 per pound of salt.