Study the substitution of fossil fuels by RDF produced from municipal solid waste of HaNoi : M.A Thesis: Waste management and contaminated site treatment

However, an efficient solution for solid waste management especially municipal solid waste management is still a challenge in Vietnam.. One reason is that waste management in Vietnam lac

A C K N O W L E D G E M E N T

I own my deepest gratitude to my supervisor Prof Nguyen Thi Diem Trang Without her patiently support and believing, I could not complete this thesis She gave me great opportunities for learning new things as well as training myself

I would like to express my thankfulness to Prof Bilitewski, Technische Universität Dresden, Vietnam National University and The German Academic Exchange Service (DAAD) for organizing this Master course It is also an honor for me to study with devoted professors and lecturers within this course They not only gave me the knowledge but also a new vision, a new way of thinking

It is a pleasure to thank those who made this thesis possible Ms Dang Ngoc Chau and my three friends Hop, Tao, Chuong I am also grateful for Ms Tran Thi Nguyet because

of her valuable comments and support during my thesis wri ting

I would like to thank my many of my colleagues for their encouragement during this course and for the time we spent together The special thank goes to my parent and my little sister for their love and endless support

Last but not least, I would like to show my gratitude to

my amant Thank you for always standing by my side and helping me overcome difficult time

2.3.2 N itrous oxide em ission 37

3 R e s u l t s a n d d i s c u s s i o n 38

3.1 RDF preparing process c o n tro l 38

3.1.1 Stabilization tim e 38

3.1.2 T em perature 39

3.1.3 Leachate volume 41

3.1.4 Water c o n ten t 42

3.2 RDF q u a lity 44

3.2.1 R D F com position 44

3.2.2 H eating va lu e 45

3.3 GHGs estimation 47

3.3.1 Pre-treatment s te p 4 7 3.3.2 R D F utilization s te p 48

3.3.3 Total GHGs em ission 49

C o n c l u s i o n 51

R e f e r e n c e s 5 2

M a ster Thesis L ist o f figures/ tobies

Li s t o f f i g u r e s

Figure 1: Global energy consumption from 1985 to 2010 (million tons o f oil

equivalent) [1 ] 9

Figure 2: Rotterdam product oil prices - US dollars per barrel [ 1 ] 10

Figure 3: Natural gas price (dollars/Btu) [ 1 ] 11

Figure 4: Shares o f world primary energy [ 1 ] 12

Figure 5: Electricity consumption in Vietnam (kWh per c a p ita ) 13

Figure 6 : Share o f total primary energy supply in Vietnam in 2 0 0 8 14

Figure 7: Waste composition o f Hanoi [ 2 0 ] 15

Figure 8 : Densified RDF (Saitama Prefectural Environmental Management Center, J a p a n ) 20

Figure 9: Schematic Representation o f MBT Process [8 | 23

Figure 10: Herhof Stabilat method [11] 25

Figure 11: Schematic diagram o f MBT CD.08 [14] 28

Figure 12: Heat value o f RDF product - MBT CD.08 method [ 14] 29

Figure 13: RDF composition for 3 barrels 31

Figure 14: RDF sample preparing p ro ce ss 32

Figure 15: Waste barrel 33

Figure 16: Temperature in stabilization barrels 39

Figure 17: Composting temperature depending on C:N r a tio 40

Figure 18: Temperature differences in stabilization barrels 41

Figure 19: Leachate v o lu m e 42

Figure 20: Water c o n te n t 43

Figure 21: Waste input composition (left) and estimated RDF output composition (right) - (a) sample 1, (b) sample 2, (c) sample 3 45

Figure 22: Gross heating value comparison with fossil fuel and RDF from different studies 47

Figure 23: GHGs emission from RDF sample compare with fossil fuel (kg C 0 2.Cq ,'MJ) [ 9 ] 50

L i s t OF TABLES

Table 1: Waste composition in Hanoi in 1995 and 2003 [20] 15

Table 2: MSW eeneration and collection rate in cities/towns in V ietnam 16

Table 3: Type o f refuse derived fuel 18

Fable 4: Typical RDF composition in some resions [8] 20

Table 5: Quality o f RDF from household and industrial sources [8] 21

Table 6 : Quality o f RDF in some Europe Countries [17] 22

Table 7: Conversion rate for RDF production according to treatment process and c o u n try 26

Table 8 : Annual RDF production from MSW in some countries [1 ] 27

Table 9: Waste input characteristics for RDF production (Đặng Ngọc Châu experiment) [6 ] 29

Table 10: Comparison RDF product quality [6, 14] 30

Table 11: Waste input com position 32

Table 12: Characteristics o f waste fraction (Vietnam based) [ 9 ] 35

Table 13: GW P according to IPCC [18] 36

Table 14: Stabilization tim e 38

Table 15: Reduction o f waste fraction after composting [1 6 ] 44

Tabic 16: Heating value 46

Table 17: C 0 2 emission from combustion process (kg/kg R D F ) 48

M a ste r Thesis Introduction

In t r o d u c t i o n

Vietnam is one o f the most rapidly developing countries in last decades High density o f population and quickly growing o f living standard as well as consumerism give Vietnam more and more challenges One o f them is the growth o f energy demand in all sectors Prices o f electricity and gasoline - two main energy sources in Vietnam - are constantly increasing in recent years Clean and renewable energy has become an interesting topic which draws much attention from the society as well as the scientific community

Another side-effect o f development which is also brought by consumerism and high population is rapid increase o f solid waste generation However, an efficient solution for solid waste management especially municipal solid waste management is still a challenge in Vietnam One reason is that waste management in Vietnam lacks separation at source

To cope with those problems, energy from waste is being studied and considered

a solution There are several ways for converting waste into energy which have different requirement on technology and finance One o f them is RDF production

by bio-stabilization method which is considered as a suitable way when investment is limited and there is not waste separation at source

There are several researches on this topic in Vietnam which showed possibility

o f implementation bio-stabilization as RDF production method in Vietnam

Based on previous study, this research “Study the substitution of fossil fuels by RDF produced from municipal solid waste of Hanoi” was carried out with the

following objectives:

• Assessment o f bio-stabilization process in RDF producing

• Study the influence o f waste composition on RDF quality

• Evaluation o f Green House Gases (GHG) emission and other RDF qualityparameter to assess the possibility o f substitution RDF for fossil fuel

1 T h e o r e t i c a l b a c k g r o u n d

1.1 S itu ation o f global e n e rg y c o n su m p tio n

/ / 1 G lobal energy consumption

In history, the world energy consumption is constantly increasing except some periods when it slightly reduced mainly due to economic problem In 2010, global energy consumption rebounded strongly, driven by economic recovery The growth in energy consumption was broad-based, with mature OECD economies joining non-OECD countries in growing at above-average rates All forms o f energy has grown strongly, with growth in fossil fuels in 2010 suggesting that global C 0 2 emissions from energy use grew at the fastest rate since 1969 [1]

M aster Thesis 1 Theoretical background

rapid increase since 1984 On the other hand, coal consumption also grew by 7.6% in 2010 Coal now accounts for 29.6% o f global energy consumption, up from 25.6% 10 years ago

Energy price developments were mixed Oil prices remained in the $70-80 range for much o f the year before rising in the fourth quarter With the OPEC production cuts implemented in 2008/09 still in place, average oil prices for the year as a whole were the second-highest on record (Figure 2) [1]

Figure 2: Rotterdam product oil prices - u s dollars per barrel [1]

According to 2011 Beyond Petroleum (BP) report, natural gas prices in 2010 grew strongly in the UK and in markets indexed to oil prices (including much o f the w orld’s LNG); but prices remained weak in North America - where shale gas production continued to increase - and in continental Europe (partly due to a growing share o f spot-priced deliveries) (see Figure 3) Coal prices remained weak in Japan and North America, but rose strongly in Europe due to coal production grew robustly in the u s and Asia but fell in the European Union(EU)

In recent years, people have witnessed a rapid growth o f non-fossil energy Global hydroelectric and nuclear output each saw the strongest increases since

2004 Hydroelectric output grew by 5.3%, with China accounting for more than 60% o f global growth due to a combination o f new capacity and wet weather

Worldwide nuclear output grew by 2%, with three-quarters o f the increase coming from OECD countries French nuclear output rose by 4.4%, accounting for the largest volumetric increase in the world Other renewable energy sources continued to grow rapidly [ 1]

Figure 3: Natural gas price (dollars/Btu) [1|

Global biofuels production in 2010 grew by 13.8%, or 240,000 b/d, constituting one o f the largest sources o f liquids production growth in the world Growth was driven by the US (+140,000 b/d, or 17%) and Brazil (+50,000 b/d, or 11.5%) Renewable energy used in power generation grew by 15.5%, driven by continued robust growth in wind energy (+22.7%) The increase in wind energy in turn was driven by China and the US, which together accounted for nearly 70% o f global growth These forms o f renewable energy accounted for 1.8% o f global energy consumption, up from 0 6% in 2000 [ 1]

1.1.2 Change in share o f world prim ary energy

When looking at the share o f world primary energy, oil, coal and natural gas are three main sources o f energy In the past 20 years, percentage o f oil in total primary energy consumption is reduced rapidly Energy crisis, high oil price and environmental problems are making people looking for new sources o f energy which is more sustainable Hydro and nuclear energy are popular non-fossil energy sources nowadays However, both o f them showed their disadvantages

M a ster Thesis 1 Theoretical background

Especially after nuclear crisis in Japan, March 2011, people have to look for new clean and safe energy

Figure 4: Shares of world primary energy |1]

BP predicted that world primary energy consumption grew by 45% over the past

20 years, and is likely to grow by 39% over the next 20 years Global energy consumption growth averages 1.7% p.a from 2010 to 2030, with growth decelerating gently beyond 2020

Non-OECD energy consumption is 68% higher by 2030, averaging 2.6% p.a growth from 2010, and accounts for 93% o f global energy growth OECD energy consumption in 2030 is just 6% higher than today, with growth averaging 0.3% p.a to 2030 From 2020, OECD energy consumption per capita is on a declining trend (-0 2 % p.a.)

The fuel mix changes relatively slowly, due to long asset lifetimes, but gas and non-fossil fuels gain share at the expense o f coal and oil The fastest growing fuels are renewables (including biofuels) which are expected to grow at 8.2% p.a 2010-30; among fossil fuels, gas grows the fastest (2.1% p.a.) [1]

One o f renewables source o f energy is waste Waste to energy is a hot topic in many countries It not only provides a non-fossil energy source but also solves

the problem o f waste management Recovered energy from waste is used to generate electricity and heat for household or industrial use However, generating quality fuel from waste and controlling environment impact during producing process is still challenges for developing country such as Vietnam.

1.1.3 E nergy consum ption in Vietnam

Vietnam is one o f the best performing economies in the world over the last decade Real GDP has on average grown by 7.3 percent per year during 1995-

2005 and per capita income by 6.2 percent per year In US dollar terms, income per capita rose from $260 in 1995 to a 2007 level o f $835 [2] Electricity consumption per capita increased rapidly since Vietnam changed to market economy in 1990s In only 18 years since 1990 to 2008, electricity consumption per capita in Vietnam increased from 98 kWh to 810 kWh, nearly ten times greater (see Figure 5)

"S

iB Vietnam

(http://data.worldbank.orp/indicator/EG USE.ELEC.KH.PC/countries/VN?displav=graph)

Figure 5: Electricity consumption in Vietnam (kWh per capita)

Moreover, Vietnam population is continuously increasing in the last decade despite o f many government efforts High population and improvement o f standard living push more pressure on energy supply Furthermore, the country’s industrialization and integration into the global economy are others reason for energy consumption growing in Vietnam Primary energy consumption, excluding biomass, grew at an annual rate o f 10.6% in the 2000-2005 periods Despite the fast growth, a large part o f the rural population still relies heavily on

M a ster Thesis 1 Theoretical background

non-commercial biomass energy sources, which still accounts for almost half o f total energy consumption (see Figure 6) Vietnam 's per capita consumption o f commercial energy thus remains among the lowest in Southeast Asia Energy is being used inefficiently, and energy production and distribution are poorly managed

Comb, renew & waste

(http://www iea org/'stats/pdf graphs/ VN TP ESP I pdf)

Figure 6: Share o f total primary energy supply in Vietnam in 2008

Even though renewable and waste energy accounts for 42% in total primary energy supply in Vietnam; waste used to generate energy is mainly agriculture waste and its product is only used for domestic purpose In industrial sector, main energy source is still fossil fuel There are several laboratory and pilot researches about generating energy from waste for industrial purpose but it has not been implemented in Vietnam [6, 14]

1.2 M u n ic ip a l solid w a ste m a n a g e m e n t in H an oi

1.2.1 Waste gen eration

Hanoi is the capital o f Vietnam and the country’s second largest city Its population in 2009 was estimated at 2.6 million for urban districts, 6.5 million for the metropolitan jurisdiction [23] Rapid economic growth coupled with fast urbanization in the last decade has pushed solid waste management to the forefront o f environmental challenges According to National Environmental Report (2010), waste generation in Vietnam ’s cities in 2008 was 1.45 kg/capita/day - 45% higher than in 2004 [21] Hanoi and Ho Chi Minh city

Coal/peat 19.9%

Oil 23.8%

(HCMC) are the main waste generators with 8,000 ton/day (2.92 million ton/a), accounted for 45.24% o f total urban Municipal Solid Waste (MSW); whereby HCMC produces 5,500 tons/d and the left is generated by Hanoi (2006-2007) [24].

■ Organic

■ Paper and textiles

B Plastic, rubber, leather, w ood, hair, feathers

■ Metal

■ Glass

■ Inert m atter

Figure 7: Waste composition o f Flanoi [20]

In most cities in Vietnam, MSW account for 60-70% o f total generated waste In some cities, the share o f MSW can reach 90% In Hanoi, organic fraction is the main part o f waste - 49% The other half o f generated waste are plastic, paper, textile, metal, glass, and inert matter (see Figure 7) [6]

Table 1: Waste composition in Hanoi in 1995 and 2003 [20]

Waste component

Percent o f total

Plastic, rubber, leather, wood, hair,

16.5 (Plastics 15.6)

M aster Thesis 1 Theoretical background

Waste composition in Hanoi has changed during the last decade Organic waste percentage is reducing and plastic waste percentage is increasing This is due to the more affluent lifestyles, larger quantity o f commercial activities, and more intense industrialization These activities increase the proportion o f non- degradable waste (such as plastic, metal, and glass) found in urban waste Plastics, metal, glass increased from 4.3%, 0.9% and 0.5% in 1995 to 15.6% 6.0% and 7.2% respectively in 2003 It is estimated that, the generation rate of plastic increased about 18.3% p.a Plastic which has high heating value is expected to contribute to the potential o f producing RDF from MSW in Vietnam [2 0]

1.2.2 Collection and treatm ent

MSW collection rates and efficiency vary from one area to the next depending

on the size o f the city, the distance to the urban center and the type o f collection service Hanoi, capital o f Vietnam, has the highest MSW collection rate - 98% MSW there is mainly collected by State-owner Public Urban Environment Companies (URENCO) then transported to Nam Son landfill Table 2 shows waste generation and waste collection in some big cities o f Vietnam [9]

Table 2: MSW generation and collection rate in cities/towns in Vietnam

No Name o f

city/town

Generated amount m

Collected amount m

Collection rate [%]

Reference

companies which serve o f 21.9% population The result showed that around 4%

o f collected MSW is composted: the rest is disposed at landfill-sites [13]

In Hanoi, Cau Dien composting plant was established in 1992 under the management o f Hanoi URENCOs dealing with municipal solid wastes, designed capacity is 60 tons/d In 2002 the plant was expanded and upgraded in capacity

to 140-150 tons/d The compost products o f Cau Dien is trading on market and the trading amount is increasing yearly, 2.114 tons in 2004: 2,735 tons in 2005; 2.799 tons in 2006 and 4,485 tons in 2007 [9]

Since 1997, waste incinerators were built in Vietnam; however this method is only applied for healthcare waste due to its high expense [9]

Reuse and recycling in Vietnam reach a high rate Many households have a habit

o f separation recyclable waste then giving or selling it away This is the reason that metal, textile only account for 6% and 1.9% respectively in waste stream However, people are losing the custom due to economy develops and standard living increases Recyclable waste is then recycled mainly in small craft village around city

As for waste composition o f Hanoi, there is high percentage o f plastic and it is still increasing This kind o f waste contains high energy - heating value Therefore dumping plastic in landfill is not only the problem o f non-degradable,

it also a waste o f resources However, recovery energy from waste is still new subject in Vietnam There are several researches and pilot studies on this topic, but it is still not implemented in reality More detail o f recent researches and studies will be given in the next part o f this thesis

1.3 R e fu se-d er iv e d fuel (R D F )

1.3.1 History

RDF or refuse derived fuel was developed due to high demand o f MSW treatment Date back to XIX century, many household in USA and Europe burned their waste in open-burning The first systematic cremation o f waste at municipal level was built in Nottingham, England in 1874 However heat from incinerator is first used to generate power in 1876 in Leeds, England Then, in

1885, a garbage furnace was established in United

M a ster Thesis 1 Theoretical background

waste plant was built in Hamburg with 35 cells o f multitubular boilers and forced draft fans [4]

By 1917 there was the first method which converting waste into combustible bricks, it is likely to be the first day o f processing activities to produce RDF which has had many improvement in the next decades However, the term '"refuse derived fuel” (RDF) had not been given until 1973 (Dr Jerome Collins)[4] In fact RDF is a category o f the generic class o f Waste-Derived Fuel (WDF) which include wood waste, hogged waste paper, and or so From residues, there are some other types o f "'Derived Fuels” such as Recovered Fuel (REF), Packaging Derived Fuel (PDF) Paper and Plastic Fraction (PPF) and Processed Engineered Fuel (PEF) which are taken from source-separated waste [8J

Although having a long history RDF has not been given the universe definition

In fact, it depends on the technologies, methods o f each sectors, each countries

European Commission Directorate General Environment defines: “Refuse-

D erived Fuel covers a wide range o f waste m aterials which have been processed to fu lfill guideline, regulatory or industry specifications m ainly to achieve a high calorific value Waste derived fu e ls include residues fro m M S W recycling, industrial/trade waste, sewage sludge, industrial hazardous waste, biomass waste, e tc ” [8]The American Society for Testing and Materials (ASTM) has defined several forms o f RDF, as shown in Table 3 [4]

Table 3: Type of refuse derived fuel

ASTM Description

Designation

RDF-1 Waste used as fuel in as-discarded form

RDF-2 Wastes processed to coarse particle size with or without magnetic

metals

RDF-3 Shredded fuel derived from MSW has been processed to removed

metal, glass, and other inorganic materials (this material has a particle size such that 95 wt.% passes through a 50 mm square mesh)

RDF-4 Combustible waste processed into powder form: 95 wt.% passing 10

mesh screen (2 mm)

RDF-5 Combustible waste densified (compressed) into pellets, slugs,

cubettes, or briquettes (this is d-RDF)

RDF-6 Combustible waste processed into liquid fuel

RDF-7 Combustible waste processed into gas fuel

RDF-1 in Table 3 refers to MSW as fuel in the as-received or as-discarded condition Worldwide RDF-1 is the major form o f RDF used Another term for RDF-5 is densified refuse derived fuel (d-RDF) This was chosen as a generic class to include pellets, briquettes, cubettes and the like by Alter in 1975 in a proposal to the U.S Environmental Protection Agency [4]

One important term in R D F's definitions is "high calorific value" This is to be one o f the important parameters considered during RDF production, which is given more detail in the follow ing sections

1.3.2 Characteristics

As for A S T M 's types o f RDF, waste can be processed to make fuel in solid, liquid or gas phase In the content o f this thesis, only solid RDF will be concentrated and it will be mentioned as RDF from here RDF can be produced under the fluff or densified forms As regards Huff RDF, it is not biologically stable and difficult to store, therefore, it must be used within 2 or 3 days This kind o f RDF has low bulk density, resulting in the limited market and in demanding the proper design o f combustion systems

In terms o f densified or pelletized RDF (Figure 8), it has advantages over fluff type It is transportable and easier to handle and store If kept under right condition, densified RDF can be stored indefinitely This kind is also suitable for burning on wider range o f combustion systems However, due to the well preparation, it is also cost more than fluff RDF Therefore, one factor should be care about when choosing between fluff RDF and pelletized RDF is the distance between RDF producing facility and combustion place.[5]

M a ster Thesis 1 Theoretical background

Figure 8: Densified RDF (Saitama Prefectural Environmental Management Center, Japan)

One characteristic o f MSW is heterogeneous; therefore RDFs produced from MSW has different composition Normally, RDF contains plastic (exclude recyclable plastic), paper, cardboard and textile; however proportion o f them changes depending on time, location and management system Table 4 shows RDF composition from various sources This difference can result in RDF quality especially heating value characteristic In table 4, it can be seen that the main composition in western and eastern countries is different The distinction in paper and cardboard can be a good example In Italy and UK, the percentage o f paper and cardboard is respectively 5 times and 10 times higher than it in Taiwan

Table 4: Typical RDF composition in some regions |8]

Waste fraction Flemish Region[4] ltaly(4) UK(4) Taiwan(10)

Sorting process (%)

MBT (%)

(%) (%) 25-100

mm (%)

>100 mm (%)

RDF quality can be roughly evaluated by calorific value, ash content, water content (WC) and chlorine, sulfur content Quality o f RDF produced from several kinds o f waste is shown in table 5 In this table, it can be seen that RDF from industrial waste has lower water content and higher heating value than household or commercial waste It is due to low percentage o f organic waste in industrial w'aste.

Table 5: Quality of RDF from household and industrial sources |8|

RDF source Calorific

value (MJ/kg)

Ash residue (% wt)

Chlorine content (% wt)

Sulfur content (% wt)

W ater content (% w t)

2) Data reported for Finland

Obviously, heat value has the decisive role in the way that RDF used In comparison with fossil fuel, heating value o f RDF from table 5 is lower than liquid fossil fuel (> 20 MJ/kg) and similar with heating value o f wood and coal (15-37 MJ/kg) Another important characteristic o f RDF is Chlorine content High Chlorine content will lead to damaging o f combustion system More

M a ster Thesis 1 Theoretical background

seriously, high concentrate o f Chlorine increase the risk o f Dioxins and Furans formation Heavy metal concentration is also considered when burning RDF fable 6 lists RDF standard which is required by law in some European country

Table 6: Quality of RDF in some Europe Countries (17|

• Mechanical Biological Treatment (MBT) which can be divided to aerobic

or anaerobic-MBT

• Dry Stabilization Process (DSP) In this method waste can be stabilized

by biological process or physical process

The main difference between these two methods is that in MBT method, mixed waste is separated to organic, recyclable, metal, inert, and high-caloric waste, and then each fraction will be treated or reused in different ways; Only high- caloric waste will be used for RDF production However, in DSP method, mixed waste is Firstly digested in digested drum or physically dried to reduce waste volume and water content as well as to stabilize microorganism activities before separation step

Mechanical Biological Process

M a ster Thesis 1 Theoretical background

The first step o f this method is separation Waste is separated by different methods to divide in to organic, inert, recyclables and RDF fraction (see Figure 9) Inert material, in this case including metal, will be recycled Organic matter will become input material for compost facility RDF fractions here means the high-calorific matter such as plastic, nylon, paper or textile which can not be recycle due to contaminated or mixed with PVC In some process, recyclable plastic is not separated to recycle; it is considered an RDF fraction in this case Therefore, MBT process can attain 3 main purposes: material recovery, nutrient recovery and energy recovery In order to gain such three products, the separation step can be considered as the most important process There are various ways to separate waste, some main stages including four main steps: magnetic separation, shredding, air classifying and finally screening

RDF fractions from separation process can be combusted directly or processed to make higher quality RDF In most processes, RDF fraction is shredded and dried

to meet RDF quality standard before go to market

Dry Stabilization Process

DSP can be done in several ways The main point o f this method is that mixed waste will firstly be dried to reduce volume, water content and stabilize microorganism activities In this method, organic waste is not separated to recovery It is only used to make composting condition in case o f biological stabilization Three main steps o f DSP are shredding, drying which can be physical (using heat), or biological process, inert and metal separation Figure 10 shows DSP method o f a Germany company Herhof GmbFI

• Shredding: this step aim to reduce waste size which is more suitable for

next step, and also well mix the waste to make same condition

• Drying: this step can be done in two ways Mixed waste can be dried

using provided heat (physical process) This method can obtain stable product quality in short time; however, it is costly due to energy requiring

In H erhof Stabilat method, biological process is used for drying step Waste after going through shredding step is kept in stabilization tank in 6-

7 days Here, microorganisms degrade organic material in aerobic condition generating heat The temperature in stabilization tank can reach

60-70°C depending on waste amount and air circulation This can be considered clean method because it does not require energy providing.

Evaporation Exhaust air

Road construction 1 f t ™ i

Industrial, Biofuels Power plants Methanol/Diesel

Figure 10: H erhof Stabilat method [11J

M a ste r Thesis 1 Theoretical background

• Inert and metal separation: inert and metal (non-combustible fraction)

is separated from waste Waste now containing mainly high calorific fractions can be pelletized to storing

Adv antage o f DSP is that it can be applied directly for wet and mixed waste, especially when waste separation at source is not applied and central separation need high investment

Additives for RDF

During the production o f RDF, some additives have been used for fix chlorine or

to modify properties o f RDF For example, M g(OH )2 has been used for minimizing slag formation Besides, M g(O H )2 and CaO has been used for explore chlorine retention and the effect on clinker formation [ 12]

1.3.4 R D F production and utilization / 8/

The quantity o f RDF produced per ton o f MSW varies depending on the type o f collection, treatment process and quality requirement Information collected by European Commission - Directorate General Environment indicated that the rate

o f RDF production from MSW can vary between 23 and 50% by weight o f waste processed depending on the treatment process used and country (Table 7)

Table 7: Conversion rate for RDF production according to treatment process and country

Country Treatment type Rate (%)

The total quantities o f RDF produced from MSW in the European Union have been estimated to amount to about 3 million tons Countries where RDF production is already well established are Austria, Finland, Germany, Italy, the Netherlands and Sweden Countries where RDF production is currently being developed are Belgium and the United Kingdom RDF from MSW was produced

in the past in Denmark and France but this has been discontinued for economical reasons Amount o f RDF produced from MSW in some countries is shown in table 8

Table 8: Annual RDF production from MSW in some countries j l|

Country Amount o f RDF produced from M SW (103 t/a)

• co-combustion in coal fired boilers;

• co-incineration in cement kilns;

• co-gasification with coal or biomass

1.3.5 Researches in Vietnam

RDF production is attracting more and more concerns from scientist and engineer in Vietnam There are several RDF project was carried out in Son Tay,