2013_Group09_ChE4225_M3

Dr. Felipe Chibante

Ms. Linda Bulmer

Dept. Of Chemical Engineering

University of New Brunswick

PO Box 4400, Fredericton NB, E3B 5A3

Nov 13th, 2013

Dear Dr. Felipe Chibante & Ms.Linda Bulmer,

We have enclosed “Milestone 3” which presents a general overview of our project as well as the

results of a literature review. Background information is provided for the company Enovex as well

as the gas adsorbing materials they produce. Design and project scope are outlined providing a

frame work for future work moving forward. Results of research and comparison of three of the

most prominent MOF production processes are included as well as the results of research into the

economic viability of this project. Proceeding the literature research and process selection, a base

case design is introduced with a block flow diagram explaining the main components of the

process. Also innovative additions are implemented along with major safety and environmental

considerations.

We believe you will find this report in line with your expectations, however if you have any

questions regarding this report, please do not hesitate to contact us directly at (506) 447- 0159.

Best Regards,

Group 9.

Sarbjyot Bains (Team Leader) Omar El-kadri Yousef Aloufi

Leroy Rodrigues William Cormac Goodfellow

ChE 4225: Chemical Engineering Plant Design

Milestone 3

Production of Metal Organic Frameworks (MOFs)- Enovex

Submitted to:

Ms. Linda Bulmer

Prof. Felipe Chibante

Due Date: 11/13/2013

Submitted by:

Group 9

Abstract

The objective of the following report is to cast an overview of the process and specifications of

the projected plant for the manufacturing of Metal Organic Frameworks (MOFs) and to present

the results of a literature review designed to determine which production system is the most

desirable.

The main function of MOFs is the efficient separation of gases such as nitrogen and oxygen.

The MOFs under study are to demonstrate 2-3 times better separation in comparison to current

technologies available. General client needs include an overall design process that constitutes

environmental, economic and risk assessment studies. These assessments should enable group 9

to build a green pilot size process plant that produces an approximation of 100kg/day of plant

operation that also complies with all safety and environmental regulations. Also a description of

the feedstock and production rates are mentioned as well as anticipated purity and yield will be

discussed within.

Further research will also be performed on plant location and downstream environmental

concerns regarding possible waste water, and/or disposal of hazardous waste.

Along with all the process steps, there are many constraints to be addressed, such as economic

indicators, environmental regulations, and health and safety issues. The following report will

highlight several key points that outline a responsible and sustainable operation.

Research was done into the economic viability of this project and the findings were encouraging.

There is significant market demand for materials of this type. Though a scale up of the process is

unproven, which could be seen as a liability, it is this same characteristic which gives this project

the potential for tremendous opportunity. Maximum potential profit was determined by

comparing the product market value and the costs of the precursor chemicals.

The results of an extensive literature review are presented detailing comparisons made between

three of the most prominent MOF production methods. The 3 processes examined were the

Electrochemical, Microwave Assisted and Solvothermal. Advantages and disadvantages of these

production methods were detailed and careful consideration was given in order to select the

process that will most suit Enovex’s needs. It was determined that the solvothermol process had

significant overall advantage when compared to the other methods.

Further proceeding the literature review and process selection, a base case design is introduced

demonstrating the main components of the design via a block flow diagram. Also explanation in

detail is presented for each section of the proposed BFD. Also innovative additions are

suggested, such as an overall control system that monitors and controls the process along with

recycling streams that recycle the expensive solvents needed for the process.

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Contents 1. Project Definition ...................................................................................................................................... 3

1.1 Introduction ........................................................................................................................................ 3

1.2 Design Scope ....................................................................................................................................... 4

1.2.1 General Client Needs ................................................................................................................... 4

1.2.2 Feedstock ..................................................................................................................................... 6

1.2.3 Plant Location and Environment .................................................................................................. 7

1.2.4 Decision Criteria/ Constraints ...................................................................................................... 9

1.3 Project Scheduling ............................................................................................................................ 11

2.0 Literature review ................................................................................................................................... 12

2.1 Overview of Product Markets ........................................................................................................... 12

2.1.1 Product End Uses ....................................................................................................................... 12

2.1.2 Product Specifications ................................................................................................................ 14

2.1.3 Product Pricing ........................................................................................................................... 15

2.1.4 Product Supply and Existing Producers ..................................................................................... 15

2.1.5 Product Demand ........................................................................................................................ 16

2.2 Assessment of Alternative Process Technologies ......................................................................... 16

2.2.1 Electrochemical Synthesis Process ............................................................................................ 16

2.2.2 Microwave Assisted Synthesis ............................................................................................ 19

1.2.3 Solvo/Hydro Thermal Synthesis Process ............................................................................. 22

2.5 Competitive Cost Considerations ...................................................................................................... 24

2.6 Recommended Process Technologies ............................................................................................... 25

2.7 Maximum Potential Profit ................................................................................................................. 29

3.0 Base Case Design ............................................................................................................................. 30

3.1 Pre-activation process ................................................................................................................. 32

3.1.1 Reactor process and chemistry .................................................................................................. 32

3.1.2 Filtration ..................................................................................................................................... 33

3.1.3 Drying ......................................................................................................................................... 33

3.1.4 Soaking ....................................................................................................................................... 33

3.1.5 Filtration ..................................................................................................................................... 34

3.1.6 Recycle Streams ......................................................................................................................... 34

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3.2 Activation Process ............................................................................................................................. 34

3.3 Innovation ......................................................................................................................................... 35

3.3.1 Process control and data analysis .............................................................................................. 35

3.3.2 Solvent Recycling ....................................................................................................................... 36

3.4 Health, Safety and Environmental Considerations ........................................................................... 37

3.4.1 Health and safety ....................................................................................................................... 37

3.4.2 Environmental ............................................................................................................................ 38

4.0 References ............................................................................................................................................ 39

5.0 Appendix ............................................................................................................................................... 41

Tables and Figures

Table 1- Project Schedule. .......................................................................................................................... 12

Table 2:BASF Grades. ................................................................................................................................ 14

Table 3: Product Pricing ............................................................................................................................. 15

Table 4: Electrochemical Synthesis, advantages and disadvantages summary table. ............................... 19

Table 5: Microwave Assisted Synthesis, advantages and disadvantages summary table. ......................... 21

Table 6: Solvothermal Synthesis Process, advantages and disadvantages................................................. 24

Table 7: Pros and Cons based comparison. ................................................................................................ 26

Table 8: Process Selection Matrix based on risk and value assessment according to aspect weight on

process. ....................................................................................................................................................... 27

Table 9: Raw Material Prices. ...................................................................................................................... 29

Table 10: Process aspect grading points. .................................................................................................... 41

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1. Project Definition

1.1 Introduction

Enovex is a leading technology startup company based in Atlantic Canada specializing in advanced

materials for improved separation capacities for portable and industrial O2/N2 production. Refined

O2 and N2 are both high demand products used for many purposes both industrially and

commercially. The oxygen for example is supplied to hospitals, steel and metal processing

industries among others. One of the largest users of refined nitrogen are the food industries whose

main uses are for freezing applications. There are many other uses of these products making this a

multimillion dollar industry.

Enovex has designed a unique porous material, which separates 2 to 3 times as much gas as the

existing materials available and result in a 50% drop in energy usage in the production of industrial

nitrogen. This material has the potential to reduce gas plant size by up to 66%. These high

performance materials called Metal Organic Frameworks or MOFs are a new class of porous

polymer materials which combine metals with organic ligands. They are highly tunable and

favorable for industrial gas processes (Walton, 2013).

The existing technology for non-cryogenic N2 production , carbon molecular sieves (CMS), are

inefficient and have a number of operational problems including; slow mass transfer due to kinetic

based separation, long mass transfer zones, low product recovery, limited volumetric uptake and

low material tune-ability. To address these problems Enovex has invented a metal organic

framework or MOF which exhibits equilibrium O2 selectivity, high O2 capacity and a linear

isothermal shape. Other desirable attributes include; functionalized pores for high O2 selectivity,

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a mix of meso and micro pores providing favorable kinetics and material also provides reversible

O2 adsorption (Walton, 2013).

Enovex plans to scale up the existing lab scale production processes to a commercialized pilot

enabling the contracted manufacture of the MOF material. Distribution will be accomplished by

using the supply channels of a large gas company. To date the Enovex team has raised $2.5M in

cash and $2M in capital equipment investments as well as hired multiple leading material scientists

including a consultant who is a premier scientists in the field. Enovex’s assets include a laboratory

in India with advanced equipment and have also built a PSA lab in Canada for commercial testing.

It is our teams’ intention to fulfill the client’s expressed need to advance the conceptualization,

design and specification of a MOF production facility capable of producing kilogram sized batches

of Enovex’s product (Walton, 2013).

1.2 Design Scope

The following section will be discussing general client specifications that outline the scope of design

project. Also some of the out of scope aspects are mentioned. Further discussion includes health and

safety aspects that define the decision criteria for process selection.

1.2.1 General Client Needs

Enovex has requested group 9 to design a commercialized sized pilot plant for the production of

MOF’s that have the function of separating oxygen gas from nitrogen gas via absorption. Currently

there is no existing plant for the projected design, hence the client requirements include every

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single aspect of the process design from utilities, feedstock used, to final product, pelletizing and

packaging (Walton, 2013).

The process design requirements include:

The selection of plant location based on financial aspects determined by comparing the

proximity of the plant to both the supplier of the raw materials and the buyer of the product

(Walton, 2013).

The building of the plant with all the process components from reactors, boilers, stream

lines and utility feeds to the pelletizing, packaging and storage of the product (Walton,

2013).

Abiding by all safety and design regulation set by provincial laws that govern such

processes.

Building and performing tasks based on green plant design strategies. Further safety

systems such as fire suppression systems and other non-process related designs will be

contracted to firms specialized in these fields (Walton, 2013).

Continuous monitoring of the process and input is also required. Certain indicators need

to be collected during the process to ensure input and process integrity.

An overall economic assessment for the feasibility of the plant and profitability of the

product is also a task that group 9 is required to perform with special attention for payback

period and other financial aspects of the design.

A deadline for the plant design limited at a maximum range of three years must be met

(Walton, 2013).

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1.2.1.1 Beyond Scope Limits

Optimization of the formulation.

Competitive-end of the final product.

1.2.2 Feedstock

The feedstock is a set of raw materials required for the entire process of manufacturing MOFs.

The main industrial function for MOFs is to replace existing technologies for non-cryogenic N2

production such as carbon molecular sieves (CMS). The raw materials to be processed in the plant

include metal salts (Zinc Nitrate), solvents/co-solvents (N,N-dimethylformamide), ligands/co-

ligands (Terephthalic acid) along with supplementary additives. The projected plant size is limited

to a small pilot plant that will produce approximately 100kg/day. The production rate can be

estimated conservatively to project feedstock rate in the case of having a specific production rate

requirement from Enovex. In this project case the production rate is a variable in determining the

optimal feed for the optimal product. Hence precise feedstock volumes will be determined based

on experimental trials that would find the optimal feed rates for the highest quality and yield of

product. Based on client requirements, the anticipated purity should be 95% or greater and will be

tested using a powder x-ray diffraction device. Further tests can be performed via FTIR and

physisorption to determine optimal surface area and pore volume. The process will start with an

approximation for feedstock quantities and then results of experimental trials will determine

optimal feedstock rates. Tests that are required to determine the pore size and optimal structure are

beyond the process scope, and are the responsibility of Enovex (Walton, 2013).

MOF’s can be generally described as a class of porous polymeric materials, consisting of metal

ions linked together by organic bridging ligands. The raw materials used are not the actual

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materials to be processed, where Enovex will keep this information confidential for patenting

purposes. Group 9 will be using analogous materials that will allow proper design of the process

(Walton, 2013).

1.2.3 Plant Location and Environment

The following section will discuss the variables that affect plant location as well as

environmental concerns that relate to the best location.

1.2.3.1 Plant Location Selection

The three locations that are currently being considered for the plant are:

Saint John, NB Canada, where it is in proximity to the client’s headquarters and port of

Saint John. Land costs are low but production costs very high.

India, where it is in proximity to Enovex’s Research and Development Centre and has

numerous ports for quick shipping of the product.

Europe, where it is in close proximity to most of the major clients of Enovex. It is

centrally located on the map and this makes it the best location for transportation

throughout the world.

A recommendation for plant site will be based on the following considerations:

Product distribution: Site should be in proximity to clients (air separation plants).

Feedstock availability: Site should be in proximity to required feedstock.

Relevant climatic conditions: Site should have controllable humidity as the end product is

sensitive to humidity. Site meteorology and weather conditions should be assessed.

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Property costs: The property prices and property taxes should be low to match Enovex’s

budget.

Labor Costs and Expertise Availability: Skilled labor should be available at affordable

cost. Direct labor costs include wages plus payroll, benefits and related taxes.

Regulatory environment: The local, state and federal laws and regulations should be

taken into consideration for site selection.

Geotechnical conditions: Borings must be obtained early in the process to attain the cost

and schedule implications foundation designs, structural fill, soil compaction, surcharging

and piling.

Availability of Public Sector Funding: Grants will help in reducing land costs and taxes.

Potential for expansion: The site should be large enough to expand the pilot plant into a

commercial plant.

Exact location and specific dimensions will be provided at a later date.

1.2.3.2 Environmental Concerns

A critical concern in the design of a chemical plant is its impact on the environment.

Potential concerns include:

Disposal of hazardous waste: The hazardous waste would be the unconsumed reagents in the

effluent. The non-recyclable waste material will go through an incinerator and the residue will

be landfilled. Moreover, under the reaction conditions used there is no appreciable

decomposition into other materials. Rejected finished product is also a non-recyclable source of

waste to be addressed.

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Proper operating and disposal procedures will be formed to prevent potential impacts on the

environment. A list of critical environmental permits and plans would be developed for the

chosen location by an environmental consulting company. Proper level of safety would be

provided to prevent exposure to hazardous conditions.

1.2.4 Decision Criteria/ Constraints

Flushing out and evaluating a number of process constraints will prove to be of great importance

in the process of decision-making and selecting the process design and its components. Most of

these constraints directly affect the quality and performance of the final product. Constraints

include economic feasibility, environmental risks, safety risks, technological feasibility and

regulatory issues.

1.2.4.1 Environmental aspects

Since this particular process deals with chemicals that are harmful to the environment or/and

human life, a number of safety measures will be necessary. Most of the raw materials that will be

used in the process processes flammable properties and produce hazardous vapors, therefore

measures will be needed to be taken in order to prevent any harmful effects to the environment.

Another aspect that needs to be taken into consideration is the handling of the hazardous waste.

These constrains will play an important role in finalizing the location of the plant (Wilkins, 2012).

1.2.4.2 Health and Safety

A number of measures need to be taken in order to minimize health hazards. This particular product

deals with toxic vapors, therefore the employees will need to follow proper safety protocols in

order to ensure their safety. Also safety measures will be needed to be taken in order to prevent

10

the escape of these harmful vapors to the surroundings. Some of the feeds (raw materials) processes

highly flammable properties, therefore safety precautions will be needed in order to prevent any

associated injury or damage (Walton, 2013). The raw materials and products of this process

haven’t been tested on a pilot scale, therefore more lab scale testing needs to be conducted to

ensure smooth pilot scale operation.

1.2.4.3 Economic Feasibility

A critical constraint that most industries face is financial. Since this plant is dealing with a new

product a fixed budget has not yet been set by the client, but a predicted healthy cash flow will be

essential to maintain investor interest and sustain long term operational viability.

1.2.4.4 Technological Risks

Since this project is currently at laboratory stage, proper equipment selection will be of primary

importance. One of the key criteria for this project is the purity and yield of the product, therefore

if economically feasible, control systems can be implemented throughout the process to ensure

optimum product results. An important aspect with regards to the selection of the technologies is

the cost of the equipment and facilities.

1.2.4.5 Production Reliability

An important operational constraint is a reliable power supply. The design should include some

form of power redundancy in order to ensure smooth operation of the plant.

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1.2.4.6 Legal Regulations

Since this particular plant deals with hazardous materials it is essential to abide by associated codes

and regulations in with its hosted location. The codes will focus on all the minor and major aspects

of the plant design, these include the handling of waste and quality of air. These codes will ensure

the safety of the workforce and surrounding areas. This factor could play an important role in

selecting the location for the plant.

1.3 Project Scheduling

Figure 1- Gantt Chart

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The following table lists specific dates for project milestones and deadlines.

Table 1- Project Schedule.

2.0 Literature review

The following section will discuss product end uses, and the market available for MOF-5 being

produced. Further research and discussion casts an overview of the selection process and

potential profit for the MOF production using the solvothermal process.

2.1 Overview of Product Markets

2.1.1 Product End Uses

North America’s developing interest in environmentally conscious processes and products, has

stimulated a great deal of interest in the use of MOFs in non-cryogenic nitrogen production.

Scientists at Enovex are trying to develop highly porous and tunable MOFs with favorable

characteristics for industrial gas separation. Their huge surface area and pore volume makes them

extremely useful for gas sequestration and as a catalyst.

MOFs are an extremely useful product with multiple uses:

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Hydrogen Storage: Hydrogen is a clean energy carrier and potential replacement for

petroleum products. Hydrogen storage is a critical enabling technology for the acceptance

of hydrogen powered vehicles and MOFs play a great role in storing sufficient hydrogen

at low temperatures and pressures (Yaghi, O'Keeffe, Cordova, & Furukawa, 2013).

CO2 sequestration: MOFs show substantial CO2 adsorption capacities at low and high

pressures.

Catalysis: MOFs have a huge potential in numerous catalyst applications. Their high

surface area, tunable porosity, diversity in metal and functional groups makes them highly

suitable as catalysts (Seda & Seda, 2011).

Semiconductors: It has been proven through theoretical calculations that MOFs show

properties of semiconductors and insulators with band gaps ranging between 1.0 eV and

5.5 eV.

Air Separation: MOFs have high selectivity for oxygen and the adsorption process is

completely reversible.

Drug Delivery Vehicles: MOFs can be regarded as optimal drug delivery materials due to

the possibility of adjusting their framework’s functional groups and tuning of their pore

size. (Seda & Seda, 2011)

Potential Imaging Agents: A recent study demonstrated the potential use of nanoscale

MOFs as multimodal imaging probes designed by incorporation of suitable metal ions and

organic moieties using a microemulsion-based approach (Seda & Seda, 2011).

MOFs for Sensing: MOFs having luminescent properties together with size/shape selective

sorption properties can be considered as potential sensing devices

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2.1.2 Product Specifications

Currently, BASF is the only commercial producer of MOFs. The various grades available at BASF are

shown below: (Aldrich, 2013).

Table 2:BASF Grades.

BASOLITE A100 (C8H5AlO5) Hydrophilic Aluminum MOF

BET surface area 1100-1500 m2/g

Reactivation at 200oC

BASOLITE C300(C18H6Cu3O12) Hydrophilic Copper MOF

BET surface area 1100-2100 m2/g

Reactivation at 200oC

BASOLITE Z1200(C8H12N4Zn) Organophilic Zinc, ZIF, Zeolitic

Framework

BET surface area 1300-1800 m2/g

Reactivation at 100oC

The product specification of the MOF produced by Enovex is:

Product Name: MOF-5 or IRMOF (Isoreticular Metal Organic Framework)-1

Formula: Zn4O(C8H4O4)3

Appearance(Color): Orange

Appearance (Form): Micro crystals

Infrared spectrum: Conforms to Structure

Purity (GC) > 99.5 %

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2.1.3 Product Pricing

Price of MOFs is directly proportional to their surface area per gram and purity. The prices shown

below are for lab samples and would vary for commercial applications (Aldrich, 2013).

Table 3: Product Pricing

Product Price(in $ per 100 g

of MOF)

BASOLITE A100 1295.00

BASOLITE C300 1815.00

BASOLITE Z1200 1295.00

MOF-5

50.00

From literature, it is found that MOFs have higher value in biomedical applications than in air

separation applications.

2.1.4 Product Supply and Existing Producers

The MOFs sold by Sigma-Aldrich are manufactured in a BASF pilot plant in Ludwigshafen,

Germany, in 100-kg-per-day batches. Only a portion of the plant's output is sold via Sigma-Aldrich

and that BASF uses most of the material internally for various R&D projects. It is seen that

industrial scientists in many companies are investigating framework compounds for use in

purification, storage, and transportation of gases, among other applications. (Jacoby, 2008)

The existing producers of MOFs include:

1. BASF: It is the only commercial producer of MOFs.

2. Sigma Aldrich: Supplier of customized MOFs on a lab scale.

3. Unknown Suppliers on Chemical Trading Websites: Supply reagent grade MOFs up to

five grams per day.

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2.1.5 Product Demand

MOFs are currently at Research and Development stage and therefore most of the demand is

coming from labs across the world for finding new applications of MOFs.

However, in the near future, predicted demand for MOFs is in the following sectors:

Automobile: For large scale hydrogen and methane storage.

Gas Separation: Separating oxygen and nitrogen from the air.

Reactors: As a catalyst with large surface area.

2.2 Assessment of Alternative Process Technologies

The following sections will discuss the main disadvantages and advantages of the three most

favorable processes in the industry; electrochemical synthesis, microwave assisted synthesis and

solvothermal synthesis.

2.2.1 Electrochemical Synthesis Process

Electrochemical synthesis is the synthesis of chemical compounds in an electrochemical cell.

During the electrochemical synthesis process metal ions are continuously supplied through the

anodic dissolution. It is an effective and versatile means of producing MOF’s. The figure below

provides a basic overview of an electrochemical synthesis process for the production of MOF’s.

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Figure 2: Electrochemical Synthesis of Metal Organic Framework.

2.2.1.1 Advantages

Some of the major advantages of an electrochemical synthesis process that makes it applicable in

an industry are:

Short Reaction Time: The reaction time for the implementation of an electrochemical

synthesis process is much faster than the conventional methods of synthesis. It is also

possible to have the system set in a continuous process.

Controllability of the size of the crystals: The size of the crystals can be controlled by the

manipulation of the voltage and concentration of metal ions. This can prove to be a key

feature as the specifications of the product can be altered to fit the needs of the client.

Elimination of the separation process of the anions from the synthesis solution and total

utilization of the linker: The process uses metal ions instead of metal salts. This eliminates

the reaction of the metal salts with the dissolved linker molecules that are present in the

reaction medium. Therefore total utilization of the linker can be accomplished. Also there

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is no need to separate the anions from the synthesis solution, prior to the recycling of the

solvent.

2.2.1.2 Disadvantages

The major disadvantages of an electrochemical synthesis process that makes it unsuitable for an

industrial application are:

Lower overall efficiency of the product: During the reaction some of the material that was

used in the initial stage of the electrochemical process may get trapped inside the pores,

resulting in pore blockage. This will decrease the overall efficiency of the product in terms

of adsorption.

Variation in the final product: Certain areas of the material that are electrically connected,

are the only areas that are subject to the growth. Therefore there is less uniformity in the

final product.

Cost-intensive: An electrochemical process is an expensive process to conduct. Also the

electrodes that are used during the course of the experiment, need to be changed

continuously. This will increase the overall operating cost of the plant.

Scalability of process: The electrochemical process for the manufacturing of MOF’s has

not yet been tested in an industrial application. Therefore the process may prove to be

unreliable.

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Table 4: Electrochemical Synthesis, advantages and disadvantages summary table.

Advantages Disadvantages

Short Reaction Time Lower overall efficiency of the product

Controllability of the size of the crystals Variation in the final product

Elimination of the separation process of the

anions from the synthesis solution and total

utilization of the linker

Cost-intensive

Unreliability of process

2.2.2 Microwave Assisted Synthesis

2.2.2.1 Overview of process technology

In Microwave-Assisted Synthesis, an appropriate solvent which contains a substrate mixture is

transferred to a vessel. After transferring the solvent to a vessel, the vessel is sealed and placed in

the microwave oven. At the set temperature, the microwave oven will heat the content for the

appropriate time. The permanent dipole moment of the molecule in the synthesis medium is

coupled with an applied oscillating electric field inducing molecular rotations hence resulting in

rapid heating of the liquid phase (Kerner, Palchik, & Gedanken, 2001).

Figure 3: Microwave-assisted solvothermal synthesis of MOF structures (Kerner, Palchik, & Gedanken, 2001).

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2.2.2.2 Process Chemistry

For the synthesis of microcrystals of Isoreticular Metal Organic Framework (IRMOF-1)

dissolution of a mixture of an appropriate spacing ligand and a metal precursor in N,N-

diethylformamide (DEF) solvent. In order to create a homogenous seeding environment, the

mixture is continuously stirred for about 15 minutes to get a clear solution (Jhung, et al., 2005).

H2BDC + Zn(NO3)2•4H2O Zn4O(BDC)3•(DEF)7

In a typical synthesis, an exact amount of benzenedicarboxylic acid (H2BDC) (0.033 g, 0.20 mmol)

and Zn(NO3)24H2O (0.156 g, 0.60 mmol) is dissolved in 12 mL N,N-diethylformamide (DEF)

resulting in a clear solution. The solution is heated in a microwave synthesizer for 25 seconds.

After the microwave treatment a yellow suspension is formed. The product is centrifuged and

redispersed in DEF by sonicating several times before analysis. The resulting suspended particles

of IRMOF-1 are found to be micro-sized cubic crystals with an average size of 4± μ m (Kang,

Park, & Wha-Seung, 1999).

2.2.2.3 Advantages

The advantages include:

Fast crystallization and phase selectivity: microwave assisted synthesis has advantages in

effectively saving reaction time, hastening the crystallization process, and producing

phase-pure products of MOF materials in high yield and large scale.

Narrow particle size distribution and facile morphology control.

Controllable process: commercial microwave equipment provides adjustable power

outputs and has a fiber optic temperature controller and pressure controller.

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The ability to produce new products: the growth process is not depending on nucleation

on the walls or dust particles so it allows new types of MOFs to be discovered (Kang,

Park, & Wha-Seung, 1999) (Jhung, Chang, Hwang, & Park, 2003).

2.2.2.4 Disadvantages

The disadvantages include:

Limited reproducibility: hindering reproducibility is a main issue to be considered in

microwave heating. The reaction conditions can by varied by controlling the temperature,

reaction time, and irradiation power. Different instruments are unable to give the same

conditions, ultimately hindering reproducibility (Kang, Park, & Wha-Seung, 1999).

Dangerous process: microwave heating is dangerous. Heating a closed vessel containing

volatile solvents and nitrates can cause an explosion. It creates hot spots that can accelerate

the explosion. In particular the pressure in a vessel containing a volatile solvent can be

much higher than with conventional synthesis (Jhung, Chang, Hwang, & Park, 2003).

Not yet commercialized: High manufacturing risks and no commercial scale process yet

seen light.

Table 5: Microwave Assisted Synthesis, advantages and disadvantages summary table.

Advantages Disadvantages

Fast Crystallization Limited reproducibility

Narrow particle size distribution Dangerous process

Controllable process Not commercialized yet

Producing new products

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1.2.3 Solvo/Hydro Thermal Synthesis Process

In a sealed vessel, such as a bomb or autoclave, solvents can be brought to temperatures well above

their boiling points by the increase in autogenously pressures resulting from heating. Performing

a chemical reaction under such conditions is referred to as solvothermal processing or, in the case

of water as solvent, hydrothermal processing (Yu, 2005). Solvents other than water can provide

milder reaction conditions with lower energy requirements (Yang, 2006).

Figure 4: A Graphical Representation of a Typical Autoclave.

MOFs, until now, have generally been prepared by either hydrothermal or solvothermal synthesis

methods by electric heating in small scales. Solvothermal methods have a benefit of the sol-gel

methods as well as a benefit of the hydrothermal methods. (Oliveira, Schnitzler, & Zarbin, 2003)

Benefits are precise control over the size, shape distribution, and crystallinity of the nanostructures

produced. Also, reaction temperature, reaction time, solvent type, metal salt and organic ligand

precursors can all be varied in order to achieve the desired MOF specifications.

Stainless steel autoclave (1) Precursor solution (2) Teflon liner (3) Stainless steel lid (4) Spring (5)

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2.2.3.1 Advantages

The advantages include:

Proven technology in small scale: many different MOF types using different precursors

and under different reaction conditions have been theorized and thoroughly tested in the

lab.

Leading technology: Opportunity to be a technological leader in this area.

High Demand: Currently a demand for such a material that is currently not being met

(Walton, 2013).

Low energy consumption: the solvothermal method in particular requires low heat input to

satisfy reaction temperature requirements (Yang, 2006).

Milder reaction conditions: The solvothermal method generally requires milder reaction

conditions, than hydrothermal, which allow the use of less costly equipment and lower

capital cost (Yang, 2006).

Precise specification control: MOF pore volume and structure can be more precisely

controlled to obtain material best suited to the application it was designed for.

2.2.3.2 Disadvantages

The disadvantages include:

Long reaction times: Reactions can take from hours to days to complete (Kang, Park, &

Wha-Seung, 1999).

Expensive equipment: Reaction pressures above atmospheric and nonstandard equipment

increase capital costs.

24

Unproven in large scale: Most MOF types have not been produced in more than gram

scale quantities per batch (Kim, Hye-Young Cho, & Wha-Seung Ahn, 2012).

Table 6: Solvothermal Synthesis Process, advantages and disadvantages.

Advantages Disadvantages

Proven technology Long Reaction Times

Leading technology Expensive equipment

High Demand Unproven in large scale

Milder reaction conditions

Precise specification control

2.5 Competitive Cost Considerations

The current process for MOFs production is in the R&D stage. The only company that has

commercialized (pilot size) the manufacturing of MOFs is BASF which generates approximately

$1.5 million per day for producing 100 kg of MOFs.

There are many factors to consider upon assessing the overall production costs, such as:

Raw material costs

Labor rates based on location of plant (country)

Operational and maintenance costs

Utilities

Packaging

Equipment costs

25

2.6 Recommended Process Technologies

MOF’s optimization is highly dependent on process tuning and monitoring as well as the

assessment of the flexibility and controllability of the process along with economic factors,

environmental concerns and safety issues. An assessment for the top three processes available for

MOF’s manufacturing has been conducted in section 2.4. The three processes that were found to

be the most commonly used processes for MOF’s production are the electrochemical synthesis

process, the micro-wave assisted synthesis process and the solvothermal synthesis process.

In the following three tables the selection process is conducted based on three criteria:

Pros and Cons based selection.

Value and risk evaluation method.

Grade point average for processes (see appendix).

A risk and value diagram also demonstrates the position of each process in terms of risk and value.

The most favorable placement is for the upper right quadrant which designates lower risk and

higher value.

26

Table 7: Pros and Cons based comparison.

Process (Row)

Aspect (column)

Electrochemical Synthesis Micro-wave assisted

synthesis

Solvothermal synthesis

Reaction time Faster than other

conventional methods

Quick crystallization and

selectivity

Long reaction times, can

take up to few days

Controllability of product Less uniformity in final

product

Controllable process and

process outputs

Good control of product

specifications

Environment Chemical treating

procedures produce

hazardous waste.

Micro-wave heating

produces dangerous

fumes from volatile

chemicals

Waste treatment is

minimal.

Safety risks Safety procedure

requirements are high.

The use of microwaved

processes require high

caution and safety

procedures.

Regular safety procedures

are required, nothing of

high concern.

Commercialization High cost, hence and

obstacle for

commercializing

High manufacturing risks,

no commercial scale

process yet seen light

High demand product,

several tech companies

show interest

Scalability and

Technological Maturity.

Regular replacement of

main equipment

components for this

process

High concern regarding

hindered reproducibility

caused by varying

reaction conditions

At lab scale,

reproducibility has been

proven feasible

Economical profitability Not yet commercialized,

financial indicators not

available

Not yet commercialized,

financial indicators not

available

Proven technology in

small scale, financial

indicators are positive

27

Table 8: Process Selection Matrix based on risk and value assessment according to aspect weight on process.

Aspect (Risk Weight,

Value Weight)

Selection Criteria

Process

Electrochemical

Synthesis

Microwave synthesis Solvothermal Synthesis

Risk Value Risk Value Risk Value

Reaction Time (0.08,0.10) 4 4 3 3 2 2

Specification Control

(0.15,0.05)

4 1 3 3 4 5

Environment (0.04,0.05) 2 2 3 4 4 4

Safety (0.02,0.02) 2 2 3 2 4 4

Scalability (0.2,0.15) 1 1 1 1 4 4

Product Demand

(0.14,0.3)

3 4 1 2 4 5

Energy Usage

(0.12,0.0.08)

3 3 3 2 5 5

Proven (0.2,0.2) 1 2 1 2 5 4

Capital Cost (0.05,0.05) 1 4 1 3 3 2

Overall Score 2.27 2.78 1.82 2.15 4.11 4.13

28

Figure 5: Risk and Value four quadrant evaluation for the three processes.

Furthermore table 10 (see appendix) summarizes the grade point (out of 5) given by the five

research team members based on thorough research summarized in the literature review section.

The overall comparison of all three processes determined that the solvothermal synthesis process

is the most favored due to the high controllability aspect of the product along with less

environmental concerns regarding waste and by products. Also, financial indicators show that the

solvothermal process can be a profitable one.

Electrochemical Synthesis

Microwave Assisted Synthesis

Solvothermal Synthesis

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Low

V

alu

e

H

igh

High Risks Low

Risk vs. Value

29

2.7 Maximum Potential Profit

As a primary high level evaluation of economic viability, product and precursor prices will be

considered in order to determine maximum potential profitability. A value of $15 per kilogram

will be tentatively placed on the MOF product. Since Enovex’s product is 2-3 times as effective

as existing technologies, the product value may be reevaluated depending on the results of future

economic analysis. The raw materials used are listed in the following table along with their

corresponding prices.

Table 9: Raw Material Prices.

Type of Raw Material Raw Material Price ($/Kg)

Metal Salt (Soluble Metal) Zinc Nitrate 0.50

Ligand (Linker/Spacer) Terephthalic Acid 1.20

Solvent (Reaction Medium) N,N-diethylformamide 1

A calculation is included in the appendix of a basic mass balance around the primary reactor. The

reaction equation for MOF 5 is used and a specified percent conversion of 95%. Selling price per

kilogram of product is subtracted from the sum of the industrial market values of all reactants used

in the process. Through calculation it was determined that 100 kilograms of MOF product could

yield a maximum potential profit of $1027.50.

30

3.0 Base Case Design

The BFD below outlines the overall process with stream lines and major components of the

process. Initially streams of raw materials (benzenedicarboxylic acid and hydrated salt) are

introduced to batch reactor that operates at 1000C and pressure to be determined based on the

vapor pressure of the reactants. An outlet stream flows from the reactor to the filter section of

the process where the liquid slurry from the reactor is filtered and washed via methanol using

a pressurized filter vacuum. Proceeding the filtration process a vacuum dryer is used to further

eliminate moisture from the cake. After drying, soaking the cake with methanol to further

dissolve the DEF from the main structure of the MOF. A second filtration step is required after

the soaking process. (Adedibu & Isaac, 2012)

After the final filtration process, MOF-5 is tested using a Powder Diffraction X-ray device to

ensure stability of MOF-5 and that the pore volumes meet the expected dimensions for optimal

separation functionality. (Adedibu & Isaac, 2012)

Once the MOF has been tested for quality, it is subjected to the activation phase where the

stability and porosity of the MOF are reinforced (Adedibu & Isaac, 2012).

A preliminary mass balance can also be viewed in the appendix.

31

Figure 6: Proposed BFD

32

3.1 Pre-activation process

3.1.1 Reactor process and chemistry

R-100 is the major reactor proposed for the MOF manufacturing plant. The reactor will run in

batch mode and is similar to an autoclave. Solvents are brought to temperatures well above their

boiling points by the increase in self-generated pressures resulting from heating. The resulting

solvothermal process is proven and has precise control.

Figure 7: A Graphical representation of a typical Autoclave.

For the synthesis of microcrystals of MOF-5, mixture of an appropriate spacing ligand and a metal

precursor in N,N-diethylformamide (DEF) solvent are mixed.

3H2BDC + 4Zn(NO3)2•4H2O Zn4O(BDC)3•(DEF)7 + 7H2O

In the synthesis, a measured amount of benzenedicarboxylic acid (H2BDC) and Zn(NO3)2.4H2O is

dissolved in N,N-diethylformamide (DEF) resulting in a clear solution containing MOF-5, DEF

solvent and water (Strachan, et al., 2010).

The bound DEF of the post reaction product will be removed during the methanol soaking process

to result in a chemical compound of the form: Zn4O(BDC)3.

Stainless steel autoclave (1) Precursor solution (2) Teflon liner (3) Stainless steel lid (4) Spring (5)

33

3.1.2 Filtration

The filtration process is a very important part of the overall process since our product is moist

sensitive and it is critical to remove all the water coming from the product (See reaction equation

in section above) (Heinsmann, 1990) (Adedibu & Isaac, 2012).

The input to the filtration system includes unreacted raw material such as the hydrated salt and

benzenedicarboxylic acid along with the diethyl formamide (DEF). During the filtration process

the major components being removed are water and the solvent DEF. It is of utmost importance to

control the pressure of the vacuum filtration in order to avoid any damage to the crystal structure

of MOF-5. Also during this process the filtered product is washed with methanol to remove most

of the DEF solvent.

3.1.3 Drying

The drying process involves further removal of water at low pressure vacuum suction using and

industrial dryer. The pressure applied mustn’t exceed levels that would damage the crystal

structures of MOF-5 (Adedibu & Isaac, 2012) (Heinsmann, 1990).

3.1.4 Soaking

The resulting crystals from the drying process are to be soaked with methanol to dissolve the DEF

from the crystals and prepare the MOF for the final step of drying (Walton, 2013) (Adedibu &

Isaac, 2012).

34

3.1.5 Filtration

After the soaking process further filtration following the same filtration mechanism in the previous

section. In this filtration process lower vacuum pressure is required since MOF-5 is at the final

stages to be tested for pore volume and stability of structure. (Heinsmann, 1990)

3.1.6 Recycle Streams

Due to the high price of solvents and washing materials (DEF and methanol), recycling streams

were added to the process. This addition will ensure the reduction of waste, and also help reduce

the cost of the solvent and washing material.

3.2 Activation Process

Commissioning is a process by which the quality of the MOF can be tested and controlled. This

stage can be of great importance as it is used to identify any problem that may exist in the overall

process.

The Powder Diffraction X-ray (PDXR) is used to determine the structural characteristics of the

produced MOF’s. Samples of the MOF from the pre-activation process is sent through the PDXR

device to verify that the pore volumes and structure of the MOF meet the expected

specifications. Upon verifying the product specifications, the MOF produced will be ready for

the activation stage.

The tested MOF is then sent through the activation stage to ensure permanent porosity, without

compromising the structure of the MOF. Through the application of heat under vacuum the

35

trapped methanol will be removed in order to achieve a porous MOF material (Adedibu & Isaac,

2012) (Walton, 2013).

3.3 Innovation

3.3.1 Process control and data analysis

The ability to control a process is highly dependent on a detailed understanding of the system

behavior. Advances in sensor technology such as high speed cameras and thermal imaging are

providing new levels of information for process modeling in cost effective ways. We now have

access to continuous and distributed data instead of single point measurements. Moreover, the rate

of data generated and stored has exploded in the last few years. Extracting useful information from

process data is not a trivial task and requires complex data analysis techniques.

Today’s world is far from linear and far from simple. MIMO (Multiple-Input-Multiple-Output)

systems are processes that have numerous components that can interact in complex ways.

Traditional engineering approaches focus on linearization and decoupling of these complexities.

The solution used in our process will rise to the challenge by integrating advanced sensor

technology with state-of-the-art data analytics and proprietary control algorithms to achieve better

levels of process performance.

The proposed software solution for our plant will be called Industrial Internet of Things. A patented

multi-dimensional non-linear software algorithm that would leverage ‛‛big data’’ information from

industrial equipment and then based on the algorithm’s optimization capability, it will provide

36

control input into the key devices that operate the manufacturing process. The end result would be

a more efficient manufacturing operation, with improved productivity, increased quality, and

lower costs (Everett, Dubay, & McKillop, 2013).

3.3.2 Solvent Recycling

A large proportion of DEF solvent is required as reaction medium since, even at the elevated

temperatures used in the reactor, the BDC ligand has limited solubility. Solvent recovery is a

necessity both from an economic and environmental perspective. Post reaction the DEF and

water mixture can be largely separated from the MOF product before the methanol wash. It is

proposed that the use of a drying agent be investigated to separate the DEF from the water of

reaction. The Merck data tables list distillation as well as CaH2 and molecular sieves as suitable

DEF drying methods. The methanol used for post reaction washing and the DEF can be kept

from mixing, for the most part, by running the post reaction DEF/water filtrate into a separate

receiver than will be used to hold the methanol wash filtrate. The primary objective of solvent

recycling will be to remove the water of reaction. Separated and dried solvents will be stored in

holding tanks, where they can then be feed back into the process feed streams as needed (Merck,

2005).

37

3.4 Health, Safety and Environmental Considerations

3.4.1 Health and safety

The most important aspects with regards to a process are health and safety. Due to the application

of hazardous and flammable raw materials, safety codes and standards will be addressed

throughout the course of the design of the process. One of the most adequate means of analyzing

and identifying the hazardous sections of the process is known as Hazard and Operability

(HAZOP). This is one of the most effective and efficient means of identifying and analyzing

potential accidents in processes involving hazardous chemicals. It is also used to develop the

means to minimize risks associated with hazardous materials. Some methods to mitigate the health

and safety issues include the following:

Due to the hazardous and flammable nature of materials being used, employees will need

to follow proper safety protocols in order to ensure their safety.

Installation of additional conveyor belt systems to ensure the smooth flow of the process.

This will ensure the continuous production of the MOF.

Installation of additional equipment to account for redundancies. This will also ensure the

continuous production of the MOF.

Identification of the most hazardous sections in the overall process and ensure the proper

training of the employees involved.

Conduct maintenance drills for all the equipment on a regular basis. This will prevent any

problems associated with equipment.

The process will be installed with pressure and temperature relief systems to avoid temperatures

or pressures outside the process limits. This will help establish a safe workplace.

38

3.4.2 Environmental

One of the major factors that influences the design of the process are the issues with regards to the

environment. Since this particular process deals with chemicals that are harmful to the

environment a number of safety measures will prove to be a necessity. Since this process deals

with hazardous and flammable material, therefore measures will be needed to be taken to ensure

the safe handling of the hazardous wastes. Some of the means to ensure the safe handling of the

wastes include:

The methanol waste can be treated and recycled back into the process to reduce the overall

hazardous wastes. This will reduce the overall flammable properties of the waste.

The hazardous waste can be treated to make it environmental friendly and then disposed in

the environment. This process is known as land treatment.

39

4.0 References

Adedibu , T. C., & Isaac, A. Y. (2012). Synthresis and Applications of Metal Organic Frameworks

Materials: A Review. Acta Chimica & Pharmaceutica Indica, 75-81.

Ahmed, I., Jeon, J., Khan, N. A., & Jhung, S. H. (2012). Synthesis of a Metal–Organic Framework, Iron-

Benezenetricarboxylate, from Dry Gels in the Absence of Acid and Salt. Crystal Growth and

Design.

Aldrich, S. (2013, 10 19). BASF Pricing. USA.

Everett, S., Dubay, R., & McKillop, J. (2013, 11 6). Intelligent Controls. Retrieved from Eigen Innovation:

http://www.eigan.co/

Heinsmann, B. (1990). Heuristics in Chemical Engineering. Boston: Butterworth Heinsmann.

Jacoby, M. (2008, August 25). Heading To Market With MOFs. Chemical and Engineering News.

Jhung, S. H., Chang, J.-S., Hwang, J. S., & Park, S.-E. (2003). Selective formation of SAPO-5 and SAPO-34

molecular sieves with microwave irradiation and hydrothermal heating. Microporous and

Mesoporous Materials.

Jhung, S. H., Lee, J.-H., Yoon, J. W., Hwang, J.-S., Park, S.-E., & Chang, J.-S. (2005). Selective crystallization

of CoAPO-34 and VAPO-5 molecular sieves under microwave irradiation in an alkaline or neutral

condition. Microporous and Mesoporous Materials.

Kang, K.-K., Park, C.-H., & Wha-Seung, A. (1999). Microwave preparation of a titanium-substituted

mesoporous molecular sieve. Catalysis Letters.

Kerner, R., Palchik, O., & Gedanken, A. (2001). Sonochemical and Microwave-Assisted Preparations of

PbTe and PbSe. A Comparative Study. Chemistry of Materials.

Kim, J., Hye-Young Cho, & Wha-Seung Ahn. (2012). Synthesis and Adsorption/Catalytic Properties of the

Metal Organic Framework CuBTC. Catalysis Surveys from Asia.

Merck. (2005, 08). Drying agents. Retrieved from Merck Data Tables: http://www.mercury-

ltd.co.il/admin/userfiles/image/Information/Drying%20Agents.pdf

Oliveira, M. M., Schnitzler, D. C., & Zarbin, A. J. (2003). (Ti,Sn)O2 Mixed Oxides Nanoparticles Obtained

by the Sol−Gel Route. Chemistry of Materials.

Seda , K., & Seda, K. (2011). Biomedical Applications of Metal Organic Frameworks. Industrial &

Engineering Chemistry Research.

40

Strachan, D., Chun, J., Henager, C., Matyas, J., Riley, B., Ryan, J., & Thallapally, P. (2010). Summary

Report for the Development of Materials for Volatile Radionuclides . Washington : US.

Department of Energy Waste Forms.

Walton, M. S. (2013, 09 25). CEO. (A-consulting, Interviewer)

Wilkins, D. F. (2012, 08 15). MSDS. Retrieved from PromoChemOnline: promochemonline.com

Yaghi, O. M., O'Keeffe, M., Cordova, K. E., & Furukawa, H. (2013). The Chemistry and Applications of

Metal-Organic Frameworks. California: Science Magazine.

Yang, F. X. (2006). Inorganic Solvents. European Journal Inorganic Chemistry, 2229.

Yu, C. J. (2005). Crystallization Growth. Solid State Chemistry, 178,321.

41

5.0 Appendix Table 10: Process aspect grading points.

Process (Row)

Aspect (column)

Electrochemical synthesis

Micro-wave assisted

synthesis

Solvothermal synthesis

Member’s 1st

name initial

W S Y O L Av

era

ge

W S Y O L Av

era

ge

W S Y O L Av

era

ge

Reaction time 4 5 3 3 4 3.8 5 4 5 5 4 4.6 2 3 2 2 3 2.4

Controllability of

product

2 3 1 2 3 2.2 3 4 3 3 4 3.4 3 5 4 5 5 4.4

Environment and

safety

3 1 2 3 3 2.4 2 1 2 2 3 2.0 3 4 3 3 4 3.4

Commercializatio

n

1 2 3 2 1 1.8 2 2 1 1 1 1.4 4 3 5 5 3 4.0

Reproducibility 2 3 4 2 3 2.8 1 1 1 2 1 1.2 4 3 5 3 3 3.6

Economical

profitability

1 2 1 1 2 1.8 2 1 1 1 2 1.4 3 4 4 3 3 3.4

Overall average 3.0 2.8 4.2