1-Plastics origin and production rates (focusing on POs).

Origin of Plastic:

Originally invented in the nineteenth century as a replacement for raw substances like ivory,

rubber, and shellac (which used to be harvested from insect secretions), plastic was conceived to

cut manufacturers free from one of the greatest obstacles in industrial production: the limits of

nature. With resins, producers would no longer have to venture across the globe for dwindling

natural resources. Now synthetic substitutes could be cooked up in onsite laboratories as needed.

This inexpensive material was designed “by man to his own specifications” and because of this it

could provide a limitless flow of inputs whenever and wherever manufacturers needed them.

Synthetics offered producers true flexibility. As Roland Barthes noted, with plastic “the

hierarchy of substances is abolished: a single one replaces them all: the whole world can be

plasticized.”( Ozdemir and Floros, 2008)

What Are Plastics, and Where Do They Come From?

Plastic is a word that originally meant “pliable and easily shaped.” It only recently became a

name for a category of materials called polymers. The word polymer means “of many parts,” and

polymers are made of long chains of molecules. Polymers abound in nature. Cellulose, the

material that makes up the cell walls of plants, is a very common natural polymer.

Over the last century and a half humans have learned how to make synthetic polymers,

sometimes using natural substances like cellulose, but more often using the plentiful carbon

atoms provided by petroleum and other fossil fuels. Synthetic polymers are made up of long

chains of atoms, arranged in repeating units, often much longer than those found in nature. It is

the length of these chains, and the patterns in which they are arrayed, that make polymers strong,

lightweight, and flexible. In other words, it’s what makes them so plastic.

These properties make synthetic polymers exceptionally useful, and since we learned how to

create and manipulate those, polymers have become an essential part of our lives. Especially

over the last 50 years plastics have saturated our world and changed the way that we live.

(Gounga et al., 2007).

The First Synthetic Plastic

The first synthetic polymer was invented in 1869 by John Wesley Hyatt, who was inspired by a

New York firm’s offer of $10,000 for anyone who could provide a substitute for ivory. The

growing popularity of billiards had put a strain on the supply of natural ivory, obtained through

the slaughter of wild elephants. By treating cellulose, derived from cotton fiber, with camphor,

Hyatt discovered a plastic that could be crafted into a variety of shapes and made to imitate

natural substances like tortoiseshell, horn, linen, and ivory.

This discovery was revolutionary. For the first time human manufacturing was not constrained

by the limits of nature. Nature only supplied so much wood, metal, stone, bone, tusk, and horn.

But now humans could create new materials. This development helped not only people but also

the environment. Advertisements praised celluloid as the savior of the elephant and the tortoise.

Plastics could protect the natural world from the destructive forces of human need.

The creation of new materials also helped free people from the social and economic constraints

imposed by the scarcity of natural resources. Inexpensive celluloid made material wealth more

widespread and obtainable. And the plastics revolution was only getting started.(Pachence et al.,

2007).

The Development of New Plastics

Panda et al. (2010) stated in 1907 Leo Baekeland invented Bakelite, the first fully synthetic

plastic, meaning it contained no molecules found in nature. Baekeland had been searching for a

synthetic substitute for shellac, a natural electrical insulator, to meet the needs of the rapidly

electrifying United States. Bakelite was not only a good insulator; it was also durable, heat

resistant, and, unlike celluloid, ideally suited for mechanical mass production. Marketed as “the

material of a thousand uses,” Bakelite could be shaped or molded into almost anything,

providing endless possibilities.

Hyatt’s and Baekeland’s successes led major chemical companies to invest in the research and

development of new polymers, and new plastics soon joined celluloid and Bakelite. While Hyatt

and Baekeland had been searching for materials with specific properties, the new research

programs sought new plastics for their own sake and worried about finding uses for them later.

Plastics Come of Age

World War II necessitated a great expansion of the plastics industry in the United States, as

industrial might proved as important to victory as military success. The need to preserve scarce

natural resources made the production of synthetic alternatives a priority. Plastics provided those

substitutes. Nylon, invented by Wallace Carothers in 1935 as a synthetic silk, was used during

the war for parachutes, ropes, body armor, helmet liners, and more. Plexiglas provided an

alternative to glass for aircraft windows. A Time magazine article noted that because of the war,

“plastics have been turned to new uses and the adaptability of plastics demonstrated all over

again.” During World War II plastic production in the United States increased by 300%.

The surge in plastic production continued after the war ended. After experiencing the Great

Depression and then World War II, Americans were ready to spend again, and much of what

they bought was made of plastic. According to author Susan Freinkel, “In product after product,

market after market, plastics challenged traditional materials and won, taking the place of steel in

cars, paper and glass in packaging, and wood in furniture.” The possibilities of plastics gave

some observers an almost utopian vision of a future with abundant material wealth thanks to an

inexpensive, safe, sanitary substance that could be shaped by humans to their every whim.

(Chem Heritage 2014)

Plastic Production Rate:

In 2011, the plastics industry continued to build on the growth of 2010. Plastics producers

enjoyed a 0.3% increase in their turnover to over 89 billion Euros. Converters experienced

greater growth with a 1.9% increase to almost 194 billion Euros. The producing sector remained

relatively stable over the last years, with a workforce of 167,000 employees and converters

employing 1.23 million European citizens. The industry in total employs a workforce of 1.45

million, including 53,000 from the plastics machinery industry. Plastics in and for Europe: the

plastics industry is one of the biggest employers in Europe Worldwide; the sector did not go

untouched by the 2008 and 2009 global economic crisis. In 2010 and 2011, it has been

recovering consistently. Global plastics production increased by 10 million tons (3.7%) to around

280 million tones in 2011, continuing the growth pattern that the industry has enjoyed since 1950

approximately by 9% per annum. (Plastics Europe.Org, 2012)

Figure 2-1 presents global and European plastics production from 1950 to 2008. Global plastics

production has grown markedly faster than European production, most likely due to the growth

of plastics production in Asia, which accounted for 93.1 Mt, or 38%, of world production in

2008. Global production is estimated by Plastics Europe to have fallen from 245 Mt in 2008 to

around 230 Mt in 2009.

Figure 1- Plastic Production in World

2-Plastic solid waste (PSW) generation; including KWT, GCC, EU, US and Asia?

Plastic solid waste generation in US:

WARM also calculates emission factors for a mixed plastics category, based on the relative

prevalence of each of the plastic types in the recovery stream, as shown in column (f) of Exhibit.

Further discussion on the end uses of these plastics is provided below.

HDPE is used for a wide variety of products, including bottles, packaging containers, drums,

automobile fuel tanks, toys and household goods. It is also used for packaging many household

and industrial chemicals such as detergents and bleach and can be added into articles such as

crates, pallets or packaging containers (ICIS, 2011a).

LDPE is used mainly for film applications in packaging, such as poultry wrapping, and in non-

packaging, such as trash bags. It is also used in cable sheathing and injection molding

applications (ICIS, 2011a).

LLDPE is used in high-strength film applications. Compared to LDPE, LLDPE’s chemical

structure contains branches that are much straighter and closely aligned, providing it with a

higher tensile strength and making it more resistant to puncturing or shearing (ICIS, 2011a).

The largest use for PET is for synthetic fibers, in which case it is referred to as polyester. PET’s

next largest application is as bottles for beverages, including water. It is also used in electrical

applications and packaging (ICIS, 2011b). PP. PP is used in packaging, automotive parts, or

made into synthetic fibers. It can be extruded for use in pipe, conduit, wire, and cable

applications. PP’s advantages are a high impact strength, high softening point, low density, and

resistance to scratching and stress cracking. A drawback is its brittleness at low temperatures

(ICIS, 2011c).

PS has applications in a range of products, primarily domestic appliances, construction,

electronics, toys, and food packaging such as containers, produce baskets, and fast food

containers (ICIS, 2011d). PVC. PVC is produced as both rigid and flexible resins. Rigid PVC is

used for pipe, conduit, and roofing tiles, whereas flexible PVC has applications in wire and cable

coating, flooring, coated fabrics, and shower curtains (ICIS, 2011e).

Table 1- Plastic Sold Waste generation in US

Plastic Sold Waste generation in Europe:

In 2008, total generation of post-consumer plastic waste in EU-27, Norway and Switzerland was

24.9 Mt (26.2 Mt in 2004, 23.7 Mt in 2006 and 24.6 Mt in 2007). The disparity between

converter demand and waste generation is due to the service life of plastics. Of plastics

converted, 60% were designed with a long service life, while 40% had a shorter service life.

Although pre-consumer plastic waste and scrap is often recovered at high rates, data on amounts

collected in Europe is not available. The main sources of plastic waste are typically the sectors

which represent the highest plastic consumption. Figure 3-1 shows the contribution of the

different sectors to the plastic waste stream in the EU-27, Norway and Switzerland in 2008.

Packaging is the largest contributor to plastic waste at 63%, well ahead of “Others” (13%),

which includes furniture, medical waste, etc. The remaining sectors include: automotive (5%),

EEE (5%), B&C (6%) and agriculture (5%). (Bio Intelligence Service 2011)

Plastic Sold Waste generation in Asia:

Economic growth and changing consumption and production patterns are resulting into rapid

increase in generation of waste plastics in the world. The world’s annual consumption of plastic

materials has increased from around 5 million tones in the 1950s to nearly 100 million tonnes;

thus, 20 times more plastic is produced today than 50 years ago. This implies that on one hand,

more resources are being used to meet the increased demand of plastic, and on the other hand,

more plastic waste is being generated. In Asia and the Pacific, as well as many other developing

regions, plastic consumption has increased much more than the world average due to rapid

urbanization and economic development.

Due to the increase in generation, waste plastics are becoming a major stream in solid waste.

After food waste and paper waste, plastic waste is the third major constitute at municipal and

industrial waste in cities. Even the cities with low economic growth have started producing more

plastic waste due to increased use of plastic packaging, plastic shopping bags, PET bottles and

other goods/appliances using plastic as the major component. In Asia region most waste is

generated in commercial sector that is 14.4%, followed by residential sector that is 10.6 % and

least waste is generated in health sector that is 0.5 %.( UNEP, 2009)

Table 2-Plastic Sold Waste generation in Asia

Plastic Sold Waste generation in GCC Countries:

He GPCA estimates that less than 10% of plastic is recycled in the Gulf. Out of the 80 million

tons of waste generated in the GCC each year, plastic waste is responsible for approximately

33% or 26 million tons. Most waste is generated by UAE, it was the second-largest generator of

household waste in the Gulf last year, much of it recyclable materials, a report to be made public

today reveals. The document, Waste Management in Gulf Cooperation Council Countries: An

Overview will be distributed today at the opening of the Middle East Waste Summit 2010, which

runs in Dubai until Thursday. GCC countries generated more than 22.2 million tones of

household waste in 2009, with 4.9 million tones - or 22 per cent of the total - coming from the

UAE. More than half of the waste, 58 per cent, was generated in Saudi Arabia. (Todorva, V

2010)

Overall Plastic waste generation:

Most of the waste is generated by US and least waste is generated by GCC nations.

Figure 4-Plastic Sold Waste generation in World

3- Overall plastic solid waste treatment

As stated before, plastic solid waste (PSW) treatment can be categorized under four

classifications. Each individual method provides a unique set of advantages making it

particularly suited and beneficial to a specific location, application or product requirement. The

purpose of recycling is to minimize the consumption of finite natural resources. This is

specifically relevant in the case of plastics which account for 4-8% of the global oil production.

Re-using plastics is the favorable course of action as it does not require energy or resources and

conserves fossil fuels. The CO2, NOx and SO2 emissions associated with plastic production are

also negated if the plastic is re-used]. The most appropriate recovery method is chosen

considering the environmental, economic and social impact of a particular technique (Plastic

Europe, 2009)

Primary recycling

Primary recycling involves the re-introduction of clean, single polymer waste into the extrusion

cycle, predominantly applied within the processing line. (Al-Salem, Lettieri & Baeyens, 2010)

Mechanical recycling

Similarly, mechanical recycling is mostly practiced by manufacturers thus applying the pre-

consumer, clean waste. Mechanical recycling According to the European plastics industry, the

environmentally and economically most favorable recycling technique is mechanical recycling.

This method was the largest recycling method in 2002, contributing for 51% to the overall

recycling, and is the second largest recovery technique for plastic waste after energy recovery.

This technique directly recovers clean plastics for reuse in the manufacturing of new plastic

products: the difficulties are mainly related to the degradation of recyclable material and

heterogeneity of plastic wastes (Al-Salem, Lettieri, Baeyens, 2009)

Feedstock recycling

Generalities Feedstock recycling comprises various advanced recycling technologies to turn

solid polymeric wastes into high value feedstock that can be used as raw materials in the

production of new petrochemicals and plastics, without any deterioration in their quality and

without any restriction regarding their application. Feedstock recycling has in theory a great

potential to boost plastics waste recovery levels [9]. These processes involve the use of moderate

to high temperatures to break the structured bonds of the polymer. They can be carried out in an

oxygen-lean environment (pyrolysis), using a high partial pressure of hydrogen (hydrocracking),

or with a controlled amount of oxygen (gasification)

Pyrolysis

A decomposition process carried out in the absence of air or in an oxygen-lean environment is

termed pyrolysis or thermal cracking. It is a flexible process and thus especially useful when

dealing with heterogeneous wastes such as comingled waste or automotive shredder residue.

Using pyrolysis, the plastic waste is converted into gases, a mixed liquid hydrocarbon fraction

(the so-called pyrolytic oil) and a solid residue (char). Since hydrogen and oxygen are absent

during the process, usually high molecular weight and hence high boiling fractions are obtained.

These are further processed and refined, resulting in petrochemical feedstock such as naphtha.

Table 1 summarizes the main products of thermal decomposition of separate polymer processes.

A summary of the obtained products after laboratory-scale pyrolysis of various polymers is

presented in table. These data reveal that within the group of analyzed polymers, only PMMA

and

polystyrene

(PS) can be

considered for

monomer

recovery. The

other

polymers are

sources of pyrolytic fuels (gas, oil, waxes). ( Brems et al., 2010)

Table 3-General Chemical recycling of Resins

Several technical designs of pyrolysis reactors have been studied in the literature. Most authors

conclude that a fluidized bed reactor is the most favorable option. This method possesses a

number of advantages which yield a more uniform product and a higher conversion rate. In-bed

reduction of gaseous pollutants, such as SO2 or HCl, moreover offers additional benefits. The

reactor is generally filled with sand particles acting as a heat transfer material. When introduced

in the reactor, the plastics quickly melt and coat the sand particles with a thin layer of polymer.

This amalgam undergoes thermal cracking and produces lighter (Kaminsky,Predel & Sadiki,

2005)

hydrocarbons which leave the reactor with the fluidizing gas. This mechanism results in a

uniform distribution of the polymers and excellent heat and mass transfer properties, resulting in

a constant pyrolysis temperature and thus highly controlled polymer cracking and a minimization

of side reactions. The process has a high efficiency for conversion of plastic waste to

petrochemical products, with an additional 10-15% used as fuel gas in the process itself. When

dealing with condensation polymers such as polyesters, polyamides, polyethylene terephtalate

(PET) and polymethylmethacrylate (PMMA), it is possible to use a pyrolysis reaction to

transform the plastic into its original synthesis monomers (Ćojbasic Ž. et al., 2011). This process

is termed chemical recycling or depolymerisation. Depolymerisation of addition polymers is

more difficult, although some studies have shown its feasibility . The efficiency of these

processes can be very high. Kaminsky et al.(2005) reported a recovery of 75% styrene and 10%

oligomers when feeding polystyrene to a fluidized bed reactor and a recovery of 98% when using

PMMA as feed.

Figure 5- Flow sheet for waste plastics

Hydrocracking

A second feedstock recycling process for plastic waste is known as hydrocracking, as described

in detail by Al-Salem et al. (2011) and Scheirs (2008). In this process, plastic waste is exposed to

a hydrogen atmosphere at pressures in excess of 100 atm, and converted into fragments of

hydrocarbons, in appearance and composition similar to crude-oil . In hydrocracking, heat

fractures molecules into highly reactive free radicals (cracking) that are saturated with molecular

hydrogen (hydrogenation) as they form. Cracking and hydrogenation are energetically

complementary processes since the cracking reaction is endothermic while hydrogenation is

exothermic. Thus the surplus of heat that is produced can be handled by employing cold

hydrogen as a quench for this reaction. The partial pressure of hydrogen must be high enough to

suppress undesirable coking or repolymerisation. Possibly, a catalyst can be used for enhancing

the hydrocracking process (Arena,et al., 2006)

Catalytic cracking

The addition of a catalyst to thermal cracking can enhance the conversion and product quality.

Catalytic cracking facilitates the selective degradation of plastic waste producing lighter fuel

fractions compared to purely thermal cracking. Early studies have been mostly limited to pure

polyolefines and fresh, pure acid catalysis, predominantly zeolites. Panda et al. (2010) discuss

the advantages of the presence of a catalyst to significantly reduce degradation temperatures and

reaction times resulting in increased conversion rates, narrower hydrocarbon product

distributions and increased gaseous product yield.

Gasification

Gasification or partial oxidation of plastic waste is performed with the controlled addition of

oxygen. The process essentially oxidises the hydrocarbon feedstock in a controlled fashion. The

primary product is a gaseous mixture of carbon monoxide and hydrogen, with minor percentages

of gaseous hydrocarbons also formed. This gas mixture is known as syngas and can be used as a

substitute for natural gas or in the chemical industry as feedstock for the production of numerous

chemicals. The inorganic ash residue becomes bound in a glassy matrix and can be used as a

component in concrete and mortar due to its high acid resistance. A hydrogen production

efficiency of 60-70% from polymer waste has been reported for a two stage pyrolysis and partial

oxidation process ( Vermeulen et al., 2011).

Figure 6- Gastification Plant

4- Biodegradable plastics and processing

Brief History Biodegradable plastics began being sparking interest during the oil crisis in the

1970’s. As oil prices increased, so did the planning and creating of biodegradable materials. The

1980’s

brought items such as biodegradable films, sheets, and mold forming materials. Green materials

(or Plant-based) have become increasingly more popular (Mohanty, 2005). This is due impart to

the fact that they are a renewable resource that is much more economical then they were in the

past (Mohanty, 2005).

What they are made of?

Biodegradable plastics can be made from many different sources and materials. One research

group from Cornell is working with “a number of fibers including those obtained from kenaf

stems, pineapple and henequen leaves and banana stems” (Replace Landfills, 2006). Their team

is working with resins made from microorganisms and commercial resins as well as composites

made from soybean protein and plant based fibers (Replace Landfills, 2006). Australian

Researchers are working plastics that are used from either starches or bacteria (Packaging

Greener, 2005). The development of new materials is constantly in progress. Researchers must

balance many variables in order to make a suitable biodegradable material.

Starch Based Plastics

Starch based plastics are mainly harvested from wheat, potatoes, rice, and corn. Of these four

starches, corn is the most commonly used and is the least expensive starch. Most sales of starch

come from the United States, which makes about $1.8 million annually. Being an extremely

versatile product, about 20% of starch is used for non-food items (Mohanty, 2005). Starch is

used for many non-food items such as making paper, cardboard, textile sizing, and adhesives

(Stevens, 2005). Starched based plastics have already been processed into eating utensils, plates,

cups and other products (Stevens, 2005).

Bacteria Based Plastic

Bacteria are an additional treatment used to create a different type of biodegradable plastics.

Using the polymer chain polyhydroxyalkanoate (PHA). PHA is produced inside bacteria cells.

The bacteria are harvested after they are grown in the culture, (Packaging Greener, 2004) and

then created into biodegradable plastics. The mechanical properties of their resins can be altered

depending on the needs of the products.

Soy Based Plastics

Soy based plastics use another alternative material used for biodegradable plastics. Soybeans are

composed of protein with limited amounts of fat and oil. Protein levels in soybeans range from

40-55%. The high amount of protein means that they must be properly plasticized when being

formed into plastic materials and films. The films produced are normally used for food coatings,

but more recently, freestanding plastics (used for bottles) have been formed from the plasticized

soybeans.( Halley, 2006)

Purpose and Needs of Biodegradable Materials

“Annual expenditure on packaging increased by more than 4% between 1994 and 1996”,

according to a report from Pira, the UK packaging consultancy. “Plastic’s share of the total

packaging expenditure remained constant over the same period, at 29%”. Since there is an

abundant amount of waste in the world, there has been a lot of interest in research devoted to the

creating of biodegradable materials. There are many advantages to There are many advantages to

creating the biodegradable plastics. Starch-based plastics have been proved to be more

environmentally friendly. Starch-based biodegradable plastics have been shown to degrade 10 to

20 times faster than traditional plastics (Kisner, 2008). When traditional plastics are burned, they

create toxic fumes which can be damaging to people’s health and the environment. If any

biodegradable films are burned, there is little, if any, toxic chemicals or fumes released into the

air. Biodegradable plastics have been proved to improve soil quality. This process is performed

as the microorganisms and bacteria in the soil decompose the material, and it actually makes the

ground more fertile (Kisner, 2008)

Processing:

The manufacturing of biodegradable polymers can include different procedures without affecting

material biodegradability. They can be synthetic (chemical) or bio-technological (effected by

microorganisms or enzymes). The most common procedures are:

Manufacturing plastics from a natural polymer that has been processed mechanically or

chemically (e.g. plastics based on destructured starch).

Chemical synthesis of a polymer from a monomer produced by bio-technological conversion

of a renewable resource (e.g. use of lactic acid produced from the fermentation of sugars for the

production of polyactic acid – PLA). In this case, the polymer is produced chemically based on a

renewable resource.

Production of a polymer by a bio-technological procedure based on a renewable resource (e.g.

fermentation of sugars where natural microorganisms synthesize thermoplastic aliphatic

polyesters, such as polyhydroxybutyrate - PHB).

Chemical synthesis of a polymer based on the components obtained by petro chemical

processes from non-renewable resources.( Augst, Kong, & Mooney, 2006).

Today, commercial biodegradable plastics are offered on the market by an increasing number of

manufacturers. Those most common materials can be classified into the following groups:

Starch-based plastics

Polylactide-based plastics (PLA)

Polyhydroxyalkanoate-based plastics (PHB, PHBV, etc.)

Aliphatic-aromatic-polyester-based plastics

Cellulose-based plastics (cellophane, etc.)

Lignin-based plastics(Cao et al., 2009)

Apart from the polymers, plastics contain other materials or additives and this combination

determines their processing options and the product's final properties. These other materials

include stabilization additives, lubricants, pigments, different fillers, and others. For

biodegradable plastics it is very important that all additional components are biodegradable as

well. The standards for compostable plastics require the testing of all additives (and other

substances used in the production of the final product, e.g. inks and colors) to ensure they do not

have a negative effect on the compost.( Datta, & Henry ,2006).

Different composites containing natural components (biocomposites) are also available. A

composite is a mixture of a polymer or plastic and the filler that is added to improve the chemical

or mechanical properties of the material or to lower the cost of the material. Biocomposites most

often consist of various natural fibers (e.g. hemp) or fillers such as wood flour. Chemically

unaltered natural fillers are biodegradable by default, but the polymer must also be biodegradable

(e.g. polylactide filled with natural fibers) for a composite to be biodegradable. It is a commonly

mistaken belief that including a natural filler (e.g. starch or wood flour) into a material that is not

biodegradable will make it biodegradable. Naturally, inorganic fillers are not biodegradable and

biodegradability does not apply to them.( Fabra & Chiralt ,2009).

5- Pyrolysis Benefits:

Pyrolytic/gasification "bakes" waste materials at relatively low temperatures (generally, 300 to

650 degrees centigrade) under highly controlled conditions that reduce or eliminate oxygen - so

waste conversion is conducted without combustion. While in incineration (combustion/burning)

of waste material converts input waste into energy and ash but is always associated with

emissions of greenhouse gases, unhealthy particulate matter and toxic residues. Even with the

most advanced and sophisticated emission controls, combustion can never achieve the

environmental standards available with the best engineered pyrolytic platforms.

Instead, a variety of waste materials are broken down into smaller carbon-containing

compounds; these molecules are collected and sold "as is" or further cost-effectively

transformed into valuable end-products that can be used to generate energy (electricity, heating

and cooling), oils/solvents, recyclable materials for resale (such as metals) and other bio-

products such as biochar - all of which can create substantial profits and new jobs while

generating carbon credits and environmental benefits.(Yassin, 2006)

The process of pyrolysis (or thermolysis) of waste materials takes place in special chambers with

reduced or no oxygen, resulting in thermal decomposition of all organic materials without

combustion. Most pyrolytic processes produce solids (char and ash), gases and oils. Depending

on the waste feedstock and pyrolysis technology used, these end-products can be sold "as is" or

cost-effectively converted into other by-products of greater commercial value. When pyrolysis (a

relatively low temperature process) is coupled with gasification (a higher temperature process,

but still combustion-free), organic waste compounds into a clean "synthetic gas" (often called

syngas or producer gas) that can then be combusted to create steam to generate electricity in

special gas engines or turbines.(Al-Saleem et. al, 2009)

Conventional incineration/combustion in conventional power plants - whether burning coal or

natural gas - also produce steam to drive turbines to generate electricity; however, they operate at

lower efficiency and produce environmentally destructive emissions. Coal burning also produces

significant amounts of "fly ash", an unavoidable consequence of combustion that can contain

toxic metals (including arsenic and mercury); the recent accidental spillage of millions of

gallons of stored fly ash in Tennessee underscores the many environmental threats associated

with coal burning.

In contrast to incineration/combustion, pyrolysis is the decomposition of organic materials

during heating in oxygen-free atmosphere to produce gas, liquid and solid residuals.

Decomposition products of the pyrolysis depend upon the heat, pressure and time the material is

held within the vessel.(Zia et. al., 2007)

There are many variations of pyrolysis technologies in commercial operation; they vary greatly

in their efficiency, cost-effectiveness, environmental impact and range of converting waste

materials to profitable products. Some of the advantages of pyrolysis over incineration/

combustion include:

• Greatly increased possibilities for recycling: with incineration, the only practical

product is energy;

• in pyrolysis, gases, oils/solvents and carbonized materials are produced; gas and

liquid products can be used as a combustion fuel

• Carbonized material can be pelletized for use as fuel, carbon black for industry, and

activated carbon for smokestack scrubbing.

• Emissions from pyrolysis are considerably lower: depending on the technology

variant employed, up to 99% of the material treated is recovered, with virtually no

effluents escaping into the environment;

• No smokestack is necessary.

• By displacing fossil-fuels, waste pyrolysis can help meet renewable energy targets,

address concerns about global warming, contribute to achieving Kyoto Protocol

commitments and generate renewable energy/carbon credits for sale or trading.

• Pyrolysis systems have been developed for a wide range of capacities and wastes,

including recovering materials and energy from residues left from materials recycling

e.g. electrical and electronic scrap, tires, mixed plastic waste and packaging residues.

• Pyrolysis is the only process that is basically insensitive to its input material:

• If properly engineered, pyrolysis equipment can accept unsorted MSW (municipal

solid waste), dioxins, contaminated soils, medical wastes and liquid materials such as

municipal sluedge with high levels of water content.

• Pyrolysis facilities require lower capital investment and have lower operating costs

than combustion plants and can be operational within 5 to 6 months of breaking

ground:

• These facilities have excellent operator safety records and function continuously at

very low noise levels;

• Combined with low profile building requirements and no smokestack, these

characteristics allow faclities to be placed in senstive locations.

• The pyrolytic technologies employed by BioSynEnergy are modular and scalable

from 10 tons up to hundreds of tons of waste processing capabilities daily. (EA,

2008.)

6- Studies of prolysis in TGA and modes of operation and results:

Pyrolysis of biomass can be described as the direct thermal decomposition of the organic matrix

in the absence of oxygen to obtain an array of solid, liquid and gas products. The pyrolysis

method has been used for commercial production of a wide range of fuels, solvents, chemicals

and other products from biomass feed stocks. Conventional pyrolysis consists of the slow,

irreversible, thermal decomposition of the organic components in biomass. Slow pyrolysis has

traditionally been used for the production of charcoal. Short residence time pyr olysis (fast, flash,

rapid, ultrapyrolysis) of biomass at moderate temperatures has generally been used to obtain high

yield of liquid products. Fast pyrolysis is characterized by high heating rates and rapid quenching

of the liquid products to terminate the secondary conversion of the products ( Ringer et al. 2008).

Depending on the pyrolysis temperature, the char fraction contains inorganic materials ashed to

varying degrees, any unconverted organic solid and carbonaceous residues produced from

thermal decomposition of the organic components. The liquid fraction is a complex mixture of

water and organic chemicals. For highly cellulosic biomass feedstocks, the liquid fraction usually

contains acids, alcohols, aldehydes, ketones, esters, heterocyclic derivatives and phenolic com-

pounds. The pyrolysis liquids are complex mixtures of oxygenated aliphatic and aromatic

compound. The tars contain native resins, intermediate carbohydrates, phenols, aromatics,

aldehydes, their condensation products and other derivatives. Pyroligneous acids can consist of

50% CH3OH, C3H6O (acetone), phenols and water. CH3OH can be produced by pyrolysis of

biomass. CH3OH arises from the methoxyl groups of uronic acid and from the breakdown of

methyl esters and/or ethers from decomposition of pectin-like plant materials. Acetic acid comes

from the acetyl groups of hemicelluloses. The pyrolysis gas mainly contains CO2, CO,

CH4,H2,C2H6,C2H4, minor amounts of higher gaseous organics and water vapour.. In a

pyrolysis study performed using bagasse bulk, the yields of condensable matter and gas

composition were examined. It was determined that their combined heat of combustion exceeds

the upper limit of the heat necessary to carbonise the biomass by 1.6–1.8 times . Primary

decomposition of biomass material (<400 C) consists of a degradation process, whereas the

secondary thermolysis (>400 C) involves an aromatization process.(Solantausta. Et.al.2010)

E ect of the pyrolysis conditions on the properties of the products.ff

Many kinds of biomass species have been subjected to pyrolysis conditions. Some of these

biomass species are as follows: Acacia wood, agricultural residues, almond shell, apple pulp,

apricot stones, Arbutus Unedo (wet biomass), Argentinean hardwood species, ash free cellulose ,

Aspidosperma Australe, Aspidosperma Quebracho Blanco Schlecht, Austrian pine, automobile

shredder residue (ASR), bagasse, bales, beech wood, birch bark, birch sapwood , birch wood,

black liquor, cellulose, cherry stones, chip piles , chlorogenic acid (bio-mass model comp.), coir

pith., corn stover , corn–potato starch gel , corn stalk, cotton cocoon shell, cotton gin wastes,

cotton stalk, cotton straw,cottonseed cake, Cynara cardunculus L., D D-glucose (biomass model

comp.), eu-calyptus wood, Euphorbia rigida , extracted oil palm fibers, filter pulp, forest wood ,

grape, g rape residue, grape seeds, grass, ground nut shell , hard-woods (beech, chestnut),

hazelnut (Corylus avellans) shells, herbaceous feed-stocks,herbaceous residues, hybrid poplar,

Italian sweet sorghum, kraft lignin, lignin (biomass model comp.) , Lodgepole pine, lucerne ,

maize, Miscanthus pellet, mixed wood waste, municipal solid waste, natural rubber, Norway

spruce, nut shells , oil palm shell, old furniture, olive husk , olive stone , petroleum residue,

pine , pine sawdust, pinus insignis saw-dust, Ponderosa pine, poplar oil, pulp black , rape plant ,

rape seed , rice husks , sa ower seed , sawdust , Scotch pine, sewage sludge, silver birch, sitkaffl

spruce , soft woods (Douglas fir, redwood, pine),soft wood bark residue, spruce, stalk of rape

seed plant, straw, straw pellet, straw rape, straw stalk, sugar cane bagasse, sun flower (Helianthus

annulus L.) pressed bagasse, sun flower press oil cake , sun flower oil, sweet sorghum bagasse ,

swine manure , switch grass , synthetic biomass, tea waste, tobacco , tobacco dust, used pallets,

waste paper, waste wood chips, wheat straw , white birch wood, white spruce, wood, wood chips

, wood cylinders, wood waste, and xylan (biomass model comp.).

Fixed bed hydropyrolysis (pyrolysis in the presence of H2) has been performed on cellulose,

sugar cane bagasse and eucalyptus wood using H2 pressures up to 10 MPa. A colloidal FeS

catalyst was used to increase overall conversion. Increasing the H2 pressure to 10MPa reduced

the O2 content of the primary oil by over 10–20% w/w. The addition of a dispersed iron sulfide

catalyst gave conversions close to 100% for all three biomass samples at 10 MPa. Although

NMR indicated that the oils became increasingly aromatic as more oxygen was removed, the

increase in

H2 pressure decreased the extent of overall aromatisation that occurs primarily due to the lower

char yields obtained.( Kaminsky et. al., 2005)

In a study, biomass in the form of oil palm shell was pyrolized in a fluidised bed with N2. The

liquid products obtained were highly oxygenated, containing a high fraction of phenol based

compounds, but there was no concentration of biologically active polycyclic aromatic hydro-

carbons (PAH) in the oil.

Pine and spruce samples were pyrolized at 550 C. The pyrolysis products were analyzed using

GC methods. The results of this study designated that large amounts of oxygenated organic

compounds, such as aldehydes, acids, ketones and metoxylated phenols, were detected. The pine

species produced less metoxylated phenols than the spruce species.

According to an investigation performing the pyrolysis of mixed wood waste in a fluidised bed

reactor at 400–550 C, the liquid products were homogenous, of low viscosity and highly oxy-

genated. The gases evolved were CO2, CO and C1–C4 hydrocarbons. Chemical fractionation of

the liquids showed that only low concentrations of hydrocarbons were present, and the oxy-

genated and polar fractions were dominant. The liquids contained considerable quantities of

phenolic compounds, and the yield of phenol and its alkylated derivatives was highest at 500 and

550 C ( Yaman, 2010).

7-Kinetic Methods:

Equilibrium methods depend upon the establishment of equilibrium. Kinetic methods rely on

measurements taken well before equilibrium is established. Most kinetic methods of analysis

take advantage of selective catalysts. The most common case is the use of enzymes (more on

that later) for the determination of organic and biological molecules. However, catalytic

reactions for inorganic species are also commonly performed. .( Solantausta. Et.al.2010)

There are many ways to categorize analytical techniques, several of which we introduced in

earlier chapters. We already classified techniques by whether the signal is proportional to the

absolute amount or the relative amount of analyte. For example, precipitation gravimetry is a

total analysis technique because the precipitate’s mass is proportional to the absolute amount, or

moles, of analyte. UV/Vis absorption spectroscopy, on the other hand, is a concentration

technique because absorbance is proportional to the relative amount, or concentration, of analyte.

A second method for classifying analytical techniques is to consider the source of the analytical

signal. For example, gravimetry encompasses all techniques in which the analytical signal is a

measurement of mass or a change in mass. Spectroscopy, on the other hand, includes those

techniques in which we probe a sample with an energetic particle, such as the absorption of a

photon.( Arthur et. al., 2008)

Another way to classify analytical techniques is by whether the analyte’s concentration is

determined by an equilibrium reaction or by the kinetics of a chemical reaction or a physical

process. The analytical methods described previously mostly involve measurements made on

systems in which the analyte is always at equilibrium. In this chapter we turn our attention to

measurements made under non-equilibrium conditions.

Methods of qualitative and quantitative chemical analysis based on the relationship between the

reaction rate and the concentration of the reactants. Kinetic methods of analysis may be applied

to the identification of both relatively large and small quantities of materials; catalytic reactions,

in which the material to be identified is either consumed during the reaction or serves as its

catalyst, are used in the latter case.

The sensitivity of kinetic methods of analysis based on such reactions is comparable to that of

activation analysis. For example, the use of catalytic reactions makes possible the identification

of manganese and cobalt at ion concentrations of 10-5 and 10-6 micrograms per milliliter,

respectively. The reaction whose rate is used to determine the concentration is called the

indicator reaction.( Solantausta. Et.al.2010)

Reactions of the following types are usually used in kinetic methods of analysis: oxidation-

reduction reactions (for example, oxidation of Mn2+ to MnO4- by hypobromite in an alkaline

medium), isotope exchange reactions between ions of like charges (for example, Ce4+—Ce3+),

substitution reactions in the inner coordination sphere of complex compounds [for example,

replacement of CN- in Fe(CN)64- by water], and various heterogeneous catalytic reactions. The

reaction rates are determined by titrimetric, gas-volumetric, photometric, polaro-graphic, and

potentiometric methods. Measurements should be performed with careful regulation of the

temperature of the reaction vessels, and high-purity reagents should be used, since the rate of

catalytic reactions depends strongly on temperature and on the presence of impurities. Kinetic

methods of analysis are used mainly to determine impurities in semiconductor elements and trace

elements in biological materials and underground waters, as well as in the analysis of ultrapure

reagents and material.( Gregoire & Bain, 2010)

Objectives of the presentation are to place kinetic methods into perspective with other analytical

appraoches, to identify concisely what is and is not a kinetic method, to group different kinetic

methods into categories that identify important differences in operational and performance

characteristics, and to suggest terminology that can identify the different approaches without

ambiguity. In addition to these major objectives, the paper includes a brief historical

development of the kinetic approach that covers the period from 1881 to the present, and

discusses some current terminology that is believed to be ambiguous and misleading. I suggest

that the detection step in analytical methods can be divided into two general categories, called

equilibrium and kinetic methods. The kinetic methods are then subdivided into two general

categories called fixed sensor-signal and variable sensor-signal methods. Each of these groups is

then subdivided into one-point, two-point, and multi-point methods, which are then further

subdivided according to what types of blanks are used, what variables are measured, and how the

measured data are used to compute enzyme activity or analyte concentration. The paper

identifies some commercial instruments that represent different approaches and briefly discusses

relative merits of different approaches(Diebold. J.P.2008.)

8-Industrial scale prolysis:

The vast stores of biomass available in the domestic United States have the potential to displace

significant amounts of fuels that are currently derived from petroleum sources. Energy security,

energy flexibility, and rural and urban job development are other drivers that support the use of

biomass to produce fuels, chemicals, and other products. The loss of traditional biomass-based

industries such as lumber and paper to overseas markets make it increasingly important to

develop this domestic resource. The rationale is even more compelling if one considers the

benefits of forest thinning to forest health and fire issues in the arid West. Proposed fuel

reduction activities would involve removing enormous amounts of biomass that have no current

market value. The only realistic market capable of consuming this volume of material is energy

and/or commodity chemicals. The primary question of “what is the best way to convert biomass

into higher value products” is then raised. (Diebold. J.P.2008)

Pyrolysis is one of a number of possible paths by which we can convert biomass to higher value

products. As such, this technology can play a role in a biorefinery model to expand the suite of

product options available from biomass. The intent of this report is to provide the reader with a

broad perspective of pyrolysis technology as it relates to converting biomass substrates to a

liquid “bio-oil” product, and a detailed technical and economic assessment of a fast pyrolysis

plant producing 16 tonne/day of bio-oil.

The international research community has developed a considerable body of knowledge on

pyrolysis over the last twenty-five years. The first part of this report attempts to synthesize much

of this information into the relevant issues that are important to advancing pyrolysis technology

to commercialization. The most relevant topics fall under the following categories:

1) Technical requirements to effect conversion of biomass to high yields of liquid bio-oil

2) Reactor designs capable of meeting technical requirements

3) Bio-oil stability issues and recent findings that address the problem

4) Product specifications and standards need to be established

5) Applications for using bio-oil in existing or modified end use devices

6) Environmental, safety, and health issues. (Reed et al. 2009)

The first two categories above represent topics that are well established and accepted in the

research community. There is little argument on requirements for producing bio-oil in high

yields. The principal technical requirement is to impart a very high heating rate with a

corresponding high heat flux to the biomass. When exposed to this environment, thermal energy

cleaves chemical bonds of the original macro-polymeric cellulose, hemicellulose, and lignin to

produce mostly oxygenated molecular fragments of the starting biomass. These fragments have

molecular weights ranging from a low of 2 (for hydrogen) up to 300-400. The lower molecular

weight compounds remain as permanent gases at ambient temperature while the majority of

compounds condense to collectively make up what is called bio-oil at yields up to 70 wt%. This

70 wt% also includes the water formed during pyrolysis in addition to moisture in the biomass

feed that ends up as water in bio-oil. The yield of permanent gas is typically 10-15 wt% with the

balance of the weight produced as char.

A number of reactor designs have been explored that are capable of achieving the heat transfer

requirements noted above. They include:

• Fluidized beds, both bubbling and circulating

• Ablative (biomass particle moves across hot surface like butter on a hot skillet)

• Vacuum

• Transported beds without a carrier gas

Of these designs, the fluidized and transported beds appear to have gained acceptance as the

designs of choice for being reliable thermal reaction devices capable of producing bio-oil in high

yields. Categories 3, 4, and 5 have important relationships to each other. The stability of the bio-

oil product is critical to the design of end use devices such as burners, internal combustion (IC)

engines, and turbines.( Bridgewater et al. 2007)

As with devices that operate on petroleum-based fuels, these devices are designed to function

properly with consistent fuel properties. To gain marketplace acceptance of bio-oils, the

consumer must have confidence that this fuel will perform reliably in a given piece of equipment

and not have deleterious effects on the equipment. The generally accepted way of providing this

level of confidence is to establish a set of specifications for bio-oil that every producer would be

required to meet. This, of course, needs to be done in concert with the designers and

manufacturers of the end use application devices. One of the key specification issues is the level

of char fines remaining in the bio-oil. While char is known to be a primary catalytic influence on

the long-term stability of the oil, it is not known how it can be removed in a cost effective

manner. The difficulty is tied to the sub-micron size of these char fines. In many respects the

issue of “clean up” of char fines from the bio-oil can be considered analogous to the cleaning of

tars and particulates from gasifier product streams. Both are critical technical hurdles that must

be overcome before the technology gains widespread commercial acceptance. The last category

concerns environmental, safety, and health issues.( Ringer et al. 2008) These issues are important

to both the producer and consumer of bio-oils. The producer must have a good understanding of

the toxicity of bio-oil so as to design and build in the appropriate engineering controls for

protecting plant operating personnel. Information about these issues is also required to meet the

requirements of commerce with respect to transportation and consumer right-to-know safety

issues. Current pyrolysis systems are relatively small from a process industries throughput

standpoint.

The pyrolysis unit is a non-standard unit operation. Although there are numerous commercial

pyrolysis units, most of these units are slow pyrolysis units and as such, may not be directly

applicable to the proposed fast pyrolysis unit. The cost for the pyrolysis system was estimated

from a fluidized bed boiler system designed by Energy Products of Idaho (Shafizadeh, 2006).

The heat recovery equipment would likely be the most similar between the systems (e.g., both

are composed of air preheater, economizer, and superheater) and was thus used as the basis for

scaling. The cost of the pyrolysis system was projected to be $3.8 million based on the steam

flow rates of the two systems with a 0.6 equipment cost exponent. This estimate should be

conservative based on several factors. The pyrolysis chamber should be significantly smaller

than the combustion chamber of a fluidized bed boiler based on the lower gas flow rates in the

pyrolysis system. The steam pressure and temperature for the EPI system is higher (950 psi) than

that for the pyrolysis system (620 psi). Finally, the EPI cost quote included NOx and SO2 control

and other systems that may not be required for the pyrolysis system. The cost of the wood feed

handling system was estimated from the Gregoire report and scaled up to 2003$. The system has

provisions for rail car or truck delivery and accommodates 4 weeks of storage. Rocks and tramp

metal are removed using a flume and two front-end loaders are used to feed the wood chips to

the process conveyor. Additional small metal pieces are removed with a magnet. The Gregoire

report estimated the cost of this system at $400,000. For this analysis, the cost is projected at a

little more than $450,000.( Yaman, 2010.)