CHAPTER 1

INTRODUCTION

1.1 Introduction

The main objective of this plant design project is the production of methane from

palm oil mill effluent (POME). POME is a form of biomass. Biomass can be defined as

organic matter that can be used as a source of energy. One example of a commonly used

biomass is wood. Wood has been conventionally used as a form of fuel till the current

era. This chapter will cover the history and background in the production of methane and

also other topics such as the application and uses of methane, market survey, site

locations and the synthesis route of the product.

1.1.1 History

Mankind has, for most of its existence, relied on renewable energy resources like

wood, windmills, water wheels and animals such as horses. The development of new

energy resources was a major driving force of the technological revolution. As for

biogas or methane, it all started in 1630 when Van Helmont mentioned about a

flammable gas emanating from decaying organic matter. Back then, Van Helmont was

one of the early observers and interpreters of natural phenomena who nowadays would

be called as “scientists”. In 1667, this gas was described more precisely by a man named

Shirley. He is now generally considered as its. An Italian physicist, Alessandro Volta

wrote a letter on November 14, 1776, about a combustible air‟ was being produced

continuously in lakes and ponds in the vicinity of Como in northern Italy. Volta

observed that when he distributed the bottom sediment of the lake, bubbles of gas would

rise to the surface. He also noticed that more bubbles came up when the sediment

contained more plant material.

In 1806, William Henry showed that Volta‟s gas was identical with methane gas.

Humphrey Davy in the early 1800s observed that methane was present in farmyard

manure piles. In 1808, Davy conducted the first laboratory experiment to produce

methane by anaerobic fermentation of wastes. In earlier periods, anaerobic fermentation

was carried out mainly as a municipal waste treatment process and resulting energy

recovery was not primary concern. In 1895, biogas from a waste treatment plant in Exter

in England was collected and used to light nearby streets.

1.1.2 Background

Biomass is a readily available renewable energy source that has received

increasing attention due to rising prices of fossil fuels and the urgent need to mitigate

anthropogenic global warming. The conversion of biomass into gaseous and liquid

biofuels by microorganisms can be considered as a way to gain safe and sustainable

energy. While the use of energy crops for bioenergy production leads to increase in food

costs, the utilization of agricultural by-products and residues for the production of

biofuels, especially biogas, can increase economic and ecological benefit of biomass use

and concomitantly prevent the accumulation of harmful bio waste in the environment.

Palm oil production is one of the major industries in Malaysia and this country

ranks one of the largest productions in the world. In Malaysia, the total production of

crude palm oil in 2008 was 17,734,441 tonnes. However, the production of this amount

of crude palm oil results in even larger amounts of POME. In the year 2008 alone, at

least 44 million tonnes of POME was generated in Malaysia. Currently, the ponding

system is the most common treatment method for POME but other processes such as

aerobic and anaerobic digestion, physicochemical treatment and membrane filtration

may also provide the palm oil industries with possible insights into the improvement of

POME treatment. The method chosen to be utilized in this plant design project is

anaerobic digestion.

Methane derived from anaerobic treatment of organic wastes has a great potential

to be an alternative fuel. It is an odorless, colorless and non-poisonous gas. The

conversion of the waste to methane, or also denoted as bio methane, is not only an

alternative cost-effective way of energy production, but it also contributes to very large

overall reductions of greenhouse gas emissions as leakages of methane into the

atmosphere are avoided.

The advantage of this process is the option to use the polysaccharide constituents

of plant material to produce energy, such as electrical power and heat, in relatively easy-

to-manage and small industrial units. Alternatively, the gas can be compressed after

purification and enrichment and then fed to the gas grid or used as a fuel in combustion

engines or cars. Its greatest advantage is the environmentally friendly aspect of the

technology, which includes the potential for complete recycling of minerals, nutrients

(phosphate) and fiber material (for humification) which come from the fields and return

to the soil, playing a functional role by sustaining the soil’s vitality for future plantation.

1.1.3 Methane as the Main Composition in Biogas

Biogas is a mixture of colorless flammable gases obtained by anaerobic digestion

of plant based (lignocellulosic) organic waste materials and also from other types of

organic waste such as cow dung, pig slurry, effluent from slaughter houses and landfill.

Biogas, a clean and renewable form of energy could very well substitute (especially in

the rural sector) for conventional sources of energy (fossil fuels, oil, etc.) which are

causing ecological-environmental problems and at the same time depleting at a faster

rate. Biogas is a mixture of mainly methane (CH4) and CO2 with very small amounts of

sulphuric components H2S. This process is carried out under anaerobic conditions, where

volatile solids are destroyed and converted to methane and carbon dioxide (Power and

Murphy, 2009).

The typical composition of the biogas is 55 – 70% CH4, 30 – 45% CO2, 0 – 2%

nitrogen and ~500 ppm H2S. Among its components, methane, or also denoted as

biomethane, is the most important one, particularly for the combustion process in

vehicles engines. Methane is a valuable renewable energy source, but also a harmful

greenhouse gas if emitted into the atmosphere. This is due to the greenhouse gas effect

of methane is about 23 times higher than carbon dioxide. Methane gas that is produced

from manure is around 4800 – 6700 kcal/m3. As compare with pure methane gas contain

energy of 8900 kcal/m3.

In addition, methane from biogas has definite advantages because it can be

produced when needed and can easily be stored. It can be distributed through the

existing natural gas infrastructure and used in the same applications like the natural gas.

Apart from utilization for renewable electricity and heat production, methane from

biogas can replace fossil fuels in the transport sector.

1.2 Biomethane

1.2.1 What is Biomethane

Biomethane is a naturally occurring gas which is produced by the so-called

anaerobic digestion of organic matter such as dead animal and plant material, manure,

sewage, organic waste, etc. Chemically, it is identical to natural gas which is stored deep

in the ground and is also produced from dead animal and plant material. However, there

are several important differences between biomethane and fossil fuel derived methane

despite the fact that both are produced from organic matter.

Natural gas is classified as fossil fuel, whereas biomethane is defined as a green

source of energy. Like its name suggests, fossil fuel derived methane is produced from

thousands or millions of years old fossil remains of organic matter that lies buried deep

in the ground. Production of fossil fuel derived methane, however, depends exclusively

on its natural reserves which vary greatly from one country to another and are not

available in limitless amounts. Biomethane, on the other hand, is produced from “fresh”

organic matter which makes it a renewable source of energy that can be produced

worldwide.

Methane is about 20 times more potent greenhouse gas than carbon dioxide if

released into the atmosphere. Furthermore, its use for power generation produces heat

and emits carbon dioxide and some other gases but despite that biomethanehas a number

of environmental benefits which make it a green source of energy. Organic matter from

which biomethane is produced would release the gas into the atmosphere if simply left

to decompose naturally, while other gases that are produced during the decomposition

process such as nitrous dioxide for instance further contribute to the greenhouse effect.

Biomethane production eliminates the release of a great deal of methane and

other harmful gases into the atmosphere. This is due to the fact that its production

eliminates exposure of the decomposing organic matter to the air which prevents

methane and other gases from escaping into the atmosphere. In addition, biomethane

reduces the need for fossil fuels by which it further reduces the emissions of greenhouse

gases into the air. By reducing the need for firewood, helps preserve the forests which in

turn helps lower concentration of carbon dioxide in the atmosphere as the trees absorb

carbon dioxide while releasing pure oxygen. The use of organic matter for biomethane

production also improves hygienic conditions and quality of life in the rural areas, and

reduces the risk of water pollution.

Since biomethane is chemically identical to natural gas, it can be used for the

same applications as natural gas. It can be used for electricity generation, water heating,

space heating, cooking as well as to fuel vehicles. Biomethane offers great potential as

an alternative source of energy, especially to fossil fuels. Despite the fact that its

usability is known for quite some time, production of biomethane started only in the

recent years as a result of the rising prices of natural gas and high electricity prices.

1.2.2 Application of Biomethame

1.2.2.1 Biomethane in Vehicles

A gas vehicle is a vehicle fuelled by a gaseous fuel not liquid fuel. There are

several types of gases that were used by the vehicles today. There are biogas,

biomethane, natural gas and petroleum gas (LPG). So, a gas vehicle is simply a normal

car, motorbike, bus or truck that uses natural gas or biomethane as a fuel rather than

petrol or diesel. In these vehicles the natural gas or biomethane fuel is burnt in an

internal combustion engine exactly like conventional liquid fuels (petrol and diesel)

through mixing the fuel with air and achieving ignition.

1.2.2.2 Definitions

1. Biogas - Describe the gas which is made in anaerobic digesters or land fill sites

typically 65% methane and 35% carbon dioxide, with contaminants in the form

of water, hydrogen sulphide and siloxanes.

2. Biomethane - Upgraded from biogas. The upgrade process removes the

contaminants and the majority of the carbon dioxide removed. Biomethane is

typically 97% methane, 2% carbon dioxide and 1% oxygen.

3. Natural gas - Such a gaseous fossil fuel consisting primarily of methane but

including significant quantities of ethane, propane, butane, and pentane.

4. Petroleum gas (LPG) - is used to describe a gas produced when refining

petroleum, typically supplied as a variable mix of propane and butane.

1.2.3 Advantage of Biomethane

There are many advantages of biomethane product which has unlimited potential

when it comes to proficient power utilization and preserve the environment at the same

time. Other advantages of biomethane are:

1. Low carbon fuel

2. Air quality benefits

3. Vehicle noise reduction

4. Reduces waste to landfill

5. Reduces cost

Figure 1.1: Greenhouse Gas Emissions for a 2002 Generic 1.6 L Passenger Car

Source:

Gas Spec CO

(g/kWh)

NHMC

(g/kWh)

CH4

(g/kWh)

NOx

(g/kWh)

PM

(g/kWh)

EEV (Directive

2005/55/EC)

3.00 0.40 0.65 2.00 0.020

Cursor 8 Litre 200

kW

G 25 2.53 0.006 0.017 0.38 0.003

GR 2.16 0.004 0.015 0.43 0.003

Table 1.1: Heavy Duty Methane Engine Options

Table 1.2: Vehicle Noise Reduction

• Reduces waste to landfill

– UK Landfill Tax Credit and Landfill Allowance Trading Scheme (LATS).

– Local authorities to trade allowances rather than pay up to £150 per tonne of waste

sent to landfill.

– Each LA is required to reduce disposal of bio-degradable waste to landfill by

progressively increasing amounts up to 65% by 2020.

1.2.4 Biomethane stabilizes the energy system.

The supply of biogas and biomethane can be maintained year around. Slurry,

manure and organic waste resulting from food processing continue to accumulate.

Similarly, harvested bio-mass stored in silos designed to be large enough to maintain the

necessary supply of energy from biogas throughout the year. Thus, the production of

biogas and biomethane makes an important contribution to a stable and reliable energy

supply. The regularity of supply has the ability to balance the fluctuating electricity

production originating from alternative renewable energy sources such as wind and

photovoltaic. This advantage is increased by the ability to inject the gas directly into the

existing natural gas grid and to use it independently from its production location.

1.2.5 Biogas as a Fuel for Combined Heat and Power Applications

Burners and boilers used to produce heat and steam can be fueled by biogas. The

direct substitution of biogas for natural gas or LPG, however, will not work for most

standard commercially available burners. At given fuel gas feed pressures, gas must

flow into combustion in the right stoichiometric ratio with air. Because of its high CO2

content, if biogas flows through the burner orifice at the pressure intended for feeding

methane or propane, the fuel-to-air ratio is insufficient to ensure flame stability.

A relatively simple option is to provide the combustion equipment with a second

as is biogas burner that operates in parallel with the first. In this case, regardless of the

fuel used, air flow is kept constant. Burner orifices for the respective burners can be set

such that each burner meters the proper amount of gas to meet combustion

stoichiometry. This could require other control measures such as (for simplest control)

complete switchovers from pure biogas fuel to the fossil alternative, and modest (a few

hours’ worth) backup biogas storage, but is otherwise straightforward.

Some operations that use landfill gas have adapted standard equipment to allow

easy switchover from different fuel sources, whether landfill biogas, natural gas, or oil.

An example of such equipment is the Cleaver-Brooks boiler at the Ajinomoto

Pharmaceutical plant in Raleigh North Carolina, which has operated successfully using

landfill gas for more than 10 years (Augenstein and Pacey, 1992; US EPA, 2001).

Conversion of a boiler system to operate on biogas typically involves the

enlargement of the fuel orifice and a restriction of the air intake. Important

considerations include the capability of the combustor to handle the increased

volumetric throughput of the lower-Btu biogas, flame stability, and the corrosive impact

of raw biogas on the burner equipment.

To prevent corrosion from H2S and water vapor, operating temperatures should

be maintained above the dew point temperature (250° F) to prevent condensation. It may

also be advisable to use propane or natural gas for startup and shut down of the system,

since higher operating temperatures cannot be maintained at these times.

If the biogas has energy content lower than 400 Btu/scf, the combustion system

may be limited by the volumetric throughput of the fuel, which may result in de-rating

of the equipment. In addition, the burner orifice should be enlarged to prevent a higher

pressure drop across the burner orifice due to the decreased heating value and specific

gravity of the biogas results. However, orifice enlargement will degrade the performance

of the burner if it is ever operated on natural gas or propane.

To resolve this problem, the propane or natural gas can be mixed with air to

create an input fuel with an equivalent pressure drop and heat input as the biogas. It is

also possible to achieve fuel flexibility by using a dual burner system, as mentioned

above. This allows optimum performance of the burners since they maintain the pressure

drop for each fuel independently.

1.3 Market Survey

Market survey of methane is about an organized effort to gather information

about methane’s potential markets or customers. In this section, market survey of

methane compromises of world and Malaysia demands.

1.3.1 Overview on Methane Demand

Malaysia has an abundance of energy resources, both renewable and non-

renewable. The largest non-renewable energy resource found in Malaysia is oil, and

second, is natural gas, primarily liquefied natural gas. The energy demand and supply by

source are also shown in relation to the country’s fuel diversification policy. In order to

reduce the overall dependence on a single source of energy, efforts were undertaken to

encourage the utilization of renewable resources.

The demand for supplemental biomethane is growing significantly as

environmental legislation concerning reduction in greenhouse gas emission. Moreover,

against a backdrop of rising crude oil prices, depletion of resources, political instability

in producing countries and environmental challenges, only renewable energy has the

potential to replace the supply of an energy hungry civilization. In this case, due to

biomethane has the potential to replace natural gas, therefore its demands are based on

natural gas demand.

Natural gas is a vital component of the world's supply of energy. Up to 50 to

75% of natural gas consists of methane. It is one of the cleanest, safest, and most useful

of all energy sources. World natural gas consumption, around 75 trillion cubic feet

(TCF) in 1994, is rising faster than that of any other fossil fuel. Although there are

abundant of gas reserves but they are unevenly distributed. The global market for gas is

much smaller than for oil because gas transport is costly and difficult. Furthermore, the

shortage of natural gas becomes a concern nowadays and the world is searching for

another source which more sustainable and not dependent. One of the best solutions is to

establish methane obtained from POME as a renewable source of energy.

A major setback for biomethane is, either it is bought on liquefied natural gas

price or a new price that the government willing to pay for renewable gas. Only few

countries that involved in biomethane production, such as Sweden, Denmark, German,

Finland and now Ontario and Canada, has their own biomethane price in order to

encourage production of biomethane. Hence there are no specific sources on price that

can be reliable for biomethane. Alternatively, in economics term, natural gas price is

used as reference.

Basically, the demand for methane is determined by population growth,

economic growth and per capita consumption. Demand for natural gas also depends

highly on the time of year, and changes from season to season. In countries with four

seasons, in the past, the cyclical nature of natural gas demand has been relatively

straightforward: demand was highest during the coldest months of winter and lowest

during the warmest months of summer. The primary driver for this primary cycle of

natural gas demand is the need for residential and commercial heating. As expected,

heating requirements are highest during the coldest months and lowest during the

warmest months. This has resulted in demand for natural gas spiking in January and

February, and dipping during the months of July and August (EIA, 2011).

1.3.2 Energy Demand by Source

Malaysia’s National Energy Policy introduced in 1979, aims to have an efficient,

secure and environmentally sustainable supply of energy in the future as well as an

efficient and clean utilization of energy. Energy is the key ingredient to any economic

activity. Adequacy of energy supply is important for the acceleration of economic

development. Energy demand by source is shown in Table 1.3.

Table 1.3: Final commercial energy demand by source 1989-2010,

Source: Sulaiman et al., 2011

Total demand for energy in Malaysia has increased from 1243.7 PJ in 2000 to

1631.7 PJ in 2005 as shown. The main demand in 2005 was for petroleum products

(derived from crude oil) at 62.7%, followed by electricity (utilizing gas, coal and oil) at

19.0%, natural gas at 15.1% and coal & coke at 3.2%. For the year 2007, the total

demand for energy is forecasted to reach 1655 PJ, with the percentage for petroleum

products to decline to 61.4% whereas for coal and coke to increase to 3.9% in line with

the national fuel diversification policy.

Interestingly, the final energy demand reported in 2007 is 1852 PJ which is an

increase of 9.8% compared to the demand in 2006. Even though there is an upward trend

in the demand which is due to the positive growth projection of the economy, the

government will make sure that its fuel diversification policy is executed so as to reduce

Malaysian’s overdependence on oil as the energy source. The policy focuses on four

main energy sources; oil, gas, coal and hydro for a reliable and secure supply of energy

to the country.

1.3.3 World Demand

Biomethane, supported by a gradually increasing share of locally produced

biomethane based on domestic waste resources, will make a very significant

contribution to a more sustainable future, thanks to the large and immediate potential for

oil substitution, significant GHG benefits and minimal air pollution.

Figure 1.4: Energy Consumption by Fuel 1980 – 2030 (Quadrillion British Thermal

Unit)

Source: EIA – Annual Energy Outlook 2009 with Projections to 2030

Based on Figure 1.4, The Energy Information Administration (EIA), in its

Annual Energy Outlook 2009, estimates that natural gas demand in the United States

could be 24.36 TCF by the year 2030. That is an increase of six percent over 2007

demand levels as compared to an expected total energy consumption increase of 12

percent (from 101.89 quadrillion BTU to 113.56 by 2030).

The EIA predicts an annual demand increase of 0.5 percent over the next 21

years and it is important to note that this steady climb in demand for natural gas could

increase as demand for low carbon fuels such as clean natural gas increase. While

forecasts made by different Federal agencies may differ in their exact expectations for

the increase demand for natural gas, one thing is common across studies: demand for

natural gas will continue to increase steadily for the foreseeable future.

1.3.4 Malaysia Demand

The main oil and gas farm is Petroleum Nasional Berhad (Petronas), a 100%

state-owned corporation. According to the Energy Information Administration’s (EIA),

Malaysia natural gas reserves in 2010 amounted to 2,328bcm, which comprised

approximately 1.23% of the world total reserves. Natural gas in Malaysia with steadily

increasing production, to date, is able to out-perform increasing domestic consumption.

Thus, exports, which ran around 1 TCF in 2009, have continued to grow. By Referring

to EIA, the latest statistics and analysis of natural gas productions and consumptions in

Malaysia is up to 2009 only. Figure 1.5 presents the production and consumption of

natural gas which could determine the net export of this product.

Figure 1.5Malaysian Natural Gas Productions and Consumption, 1991 – 2010

Source: EIA

1.3.5 Bio-methane Price

Bio-methane has no specific price, hence it is either be bought on liquefied

natural gas price or a new price that the government willing to pay for renewable gas

According to the Energy Information Administration’s (EIA) Natural Gas Weekly

Update, the current price is $4.25 per million metric British thermal units (MMBtu)

(November, 2012) which is RM 12.87 in Malaysian currency. According to Elshahed

(2010), 1 MMBtu equals to 28.26 m3 of natural gas at define temperature and pressure.

The clean and purified methane can be sold as compressed natural gas for

industrial users like oleo chemical producers or as transport fuel for taxis and express

buses. Gas Malaysia only buys natural gas from Petroliam Nasional Bhd (Petronas) at

RM15 per MMBtu, while Petronas sells a fixed annual supply of natural gas to the

manufacturing sector and the bulk, or about 60%, goes to power plants. The

manufacturing sector now uses some 15% of natural gas in the national pipeline,

following a recent additional allocation of 100 million standard cu ft. per day (mmscfd).

1.4 Synthesis Route

Figure 1.6: Overall Synthesis Route in Biomethanation

Figure 1.6 summarized the overall synthesis route in the production 100,000

MTA methane from POME. Firstly, fresh POME is pumped into anaerobic digester. In

this equipment, anaerobic digestion process will occurred in three stages before biogas is

produced. Biogas is mainly consists of methane with carbon dioxide and traces of

hydrogen sulfide.

Fresh POME

Anaerobic Digester

1. Hydrolysis and acidogenesis

2. Acetogenesis3. Methanogenesis

Biogas (CH4, CO2, H2S)

Acid Gas Removal Unit

Gas absorption unit using methyldiethanolamine (MDEA)

Stripper

CO2 and H2S

Waste Treatment

Lean amine recycles

Digestate

CH4

POME that has been utilized to produce biogas is waste and now known as

digestate. This waste then fed to waste treatment plant. Biogas produced is then entered

the acid removal unit in order to produced purified methane with 99% purity. In this acid

removal gas unit, there are two major equipments which are gas absorber and stripper.

Gas absorber is where the separation of methane from carbon dioxide and hydrogen

sulfide takes place. In this part, carbon dioxide and hydrogen sulfide are known as acid

gas.

This acid gas is removed from biogas with the help of methyldiethanolamine

(MDEA) as the absorbent. The purified methane then fed into gas compressor before

kept in gas storage. MDEA that used in this plant is recycled back into the gas absorber

via stripper. In the stripper unit, acid gas becomes the distillate product and then flare.

The amount of acid gas that been flared could be measured and calculated to obtain

CER. Meanwhile, as for the lean amine, which happened to be the bottom product is

recycled and reused in gas absorber.

1.4.1 Acid Gas in Biogas Flow

Acid gases are gases such as hydrogen sulfide and carbon dioxide. Natural gas

with hydrogen sulfide or any other sulfur containing compounds is known as sour gas.

While processing natural gas, it is vital that sour gases are removed from the stream. The

presence of sour gas in pipelines can cause corrosion. Sulfur is also lethal to humans and

animals. Carbon dioxide on the other hand should be removed from stream as it is not

combustible and also forms weak acids that can cause corrosion when water is present.

Therefore, it is an undesired component.

The most commonly used method is sour gas removal is known as sweetening or

amine gas treating. Amine solutions are brought into contact with the gas stream in an

absorber column and the acid gases are absorbed by the amine solutions. Primarily two

forms of amine solutions are used, monoethanolamine (MEA) and ethanolamine (DEA).

Regeneration of the amine solutions are done by removing the sulfur compounds and the

solutions are then recycled.

1.4.2 Method in Removing Acid Gas

It is well known that carbon dioxide is widely recognized as a major greenhouse

gas contributing to global warming. Many sources mentioned that this greenhouse gas is

produced in large quantity worldwide by many important industries, including fossil-fuel

electric power generation, steel production, chemical and petrochemical manufacturing,

and cement production. In the past several decades, continuous and rapid development

of these industries has caused considerable concern in this regard.

The growing evidence that links the greenhouse gas carbon dioxide (CO2) and

global climate change highlights the need to develop cost effective carbon sequestration

schemes. CO2 accounts for over eighty-two percent of all greenhouse gas emissions in

the U.S., even after considering its relative greenhouse warming potential (GWP).

Nearly sixty percent of CO2 is emitted by utility or industrial power systems, which are

based on fossil fuel combustion. Future power generation technologies such as fuel cells

or gasification need to mature and to lower costs to gain widespread application. Vv

vsequently, it is likely that for the next several decades the bulk of the CO2 will be

emitted from the fossil fuel-based energy infrastructure, both existing and that likely to

be added in the near term. Separation of CO2 from a mixture of gases can be

accomplished through various means: low-temperature distillation, membranes,

adsorption, physical and chemical absorption.

Chemical absorption, for example amine-type absorbents, is well suited for CO2

recovery from flue gas. The chemical reaction between CO2 and amines greatly

enhances the driving force for the separation, even at low partial pressures of CO 2. The

costs of this technology are relatively insensitive to the feed CO2 content. Consequently,

chemical absorption with amines provides the most cost-effective means of directly

obtaining high purity (>99%) CO2 vapor from flue gases in a single step.

Chemical absorption with alkanolamines has been generally used in processes

such as natural gas sweetening and hydrogen production for the rejection of carbon

dioxide. However, in these applications, the CO2 partial pressure is significantly greater

than that in flue gas applications. Several alkanolamines such as MEA

(monoethanolamine), DEA (diethanolamine), MDEA (methyldiethanolamine), DIPA

(diisopropanolamine), DGA (diglycolamine), TEA (triethanolamine) and other sterically

hindered amines have found commercial use. The particular choice of alkanolamine is

primarily dictated by the requirements of the specific application.

For many years, MEA was almost exclusively used for removal of CO2 and H2S.

However to reduce operating costs and corrosion rates, the use of MDEA-based solvents

became more prevalent. The slower rate of reaction of CO2 with MDEA was

compensated through the addition of small amounts of rate-promoting agents such as

DEA or piperazine. In applications such as natural gas treating, the state-of-the-art

technology employs MDEA-based solvents, such as. a blend of MDEA and a faster

reacting amine.

1.4.3 Methyldiethanolamine (MDEA)

Alkanolamines are widely utilised in the chemical industry. For example, they

are used in gas purification, in textile production, in the production of certain

agricultural products and surfactants. However, in spite of their importance there are

surprisingly few compilations of thermodynamics data for these compounds in the

literature at temperature and pressure conditions removed from ambient.

Methyldiethanolamine (MDEA) is a psychedelic hallucinogenic drug and

empathogen-entactogen of the phenethylamine family. It is a tertiary amine and act as a

solvent. It has a greater capacity to react with acid bases because it can be used in higher

concentrations. This advantage is enhanced by the fact that it is reacting with all of the

H2S and only part of CO2. MDEA also delivers energy savings by reducing reboiler

duties and lowering overhead condenser duties. It has proved to be highly selective for

absorption of H2S when compared to CO2 resulting in even lower circulation rates and

higher quality acid gases for recycle to sulfur recovery unit. Among MEA, DEA, and

MDEA, MEA has worst reputation for corrosion related problem.

1.5 Economic Potential 1 (EP1)

The reaction:

POME CH4 + CO2

Calculation for cost of POME (Raw material)

Material used: Palm oil mill effluent

Usage: 31 500 m3

Cost: POME is taken from palm oil mill as waste water, so only transportation cost are

calculated.

Transportation cost:

RM 2190.00/day

RM 746,790/year

Calculation for sales of biogas (Revenue)

According to the Energy Information Administration‟s (EIA) Natural Gas

Weekly Update, the current price is $3.70 per million metric British thermal units

(MMBtu) (Nov, 2012) which is RM 11.268 in Malaysian currency. 1 MMBtu equals to

28.26 m3 of natural gas at define temperature and pressure.

100,000 MT 1000 kg SM3 9534 kcal 1 mmBtu RM 13

Year MT 0.6 kg M3 252190.217 kcal MMBtu

= RM 1.229 x 108/ year

EPI = Revenue – RM Cost

= RM 1.229 x 108/ year – RM 746,790/year

= RM 1.221 x 108/ year *(positive value)

EPI > 0

From the analysis above, a value of RM 1.221 x 108/ year is obtained which is a

positive value. Hence, it can be concluded that this project is feasible.

1.6 Objectives