Utilization of Agricultural Waste to Be Bioethanol Sources as

a Solvent on Parafﬁn Wax Crude Oil Issues

M. K. Afdhol

, F. Hidayat

, M. Abdurrahman

, H. Z. Lubis

, R. K. Wijaya

and N. P. Sari

Department of Petroleum Engineering, Faculty of Engineering , Universitas Islam Riau, Pekanbaru, Indonesia

Department of Chemical Engineering, Institut Teknologi Medan, Jl. Gedung Arca No.52, Medan, Sumatera Utara,

Keywords:

Agricultural Waste, Bioethanol, Solvent, Wax Parafﬁn.

Abstract:

Crude oil is a chemical compound of saturated parafﬁn wax, aromatics, napthane, asphaltic, and resins indeed

this material produce wax deposits. Deposition of parafﬁn has potential to harmful the production due to the

existence of blockages, whether partial or the whole of the pipeline. Various techniques have been developed

to overcome this problem; one of them is the use of solvents from agriculture waste. Incidentally, the materials

are easy to obtained and economical. Based on the Central Bureau of Statistics data, the agricultural waste in

Indonesia recorded 5,883,730 tons/year for corn waste, 439,657 tons/year for pineapple skin waste, and 15.8

tons/year for rice husk waste. The potential of agricultural waste can be used as a source of raw materials for

manufacturing solvents by using bioethanol by ways of pretreatment, hydrolysis, fermentation, and distillation

process. In addition, the result of several past studies shows that bioethanol made from pineapple skin produce

8% of ethanol; bioethanol from corncobs produce 19-22% of ethanol; and bioethanol from rice husk produce

14.4227% of ethanol. Therefore, it means that agricultural waste can be used as a source of bioethanol in

manufacture of solvent and could overcome the problem of parafﬁn wax.

1 INTRODUCTION

The decline in production is an obstacle for the oil

and gas industry. Decreasing the rate of oil production

in wells will occur over time if the well is produced

continuously (Wang et al., 2003). Parafﬁn is a

straight chain consisting of 20 to 40 carbon atoms,

parafﬁn is formed at low temperatures (Taraneh et al.,

2008). There are several methods for dealing with

parafﬁn wax, including preventive methods, namely

heating methods and chemical methods, one of the

most effective methods is using hydrocarbon solvents

(Khaibullina et al., 2016). Where one way to reduce

parafﬁn wax is by injection of solvent as a wax

inhibitor (Al-Yaari et al., 2011).

Organic waste processing has been widely used,

such as: palm shells (Yuliusman et al., ; Yuliusman

et al., 2018; Afdhol et al., 2017), tea waste, coffee

grounds (Yuliusman et al., ), and inorganic waste from

plastic waste (Yuliusman et al., ). Bioethanol can be

produced from biomass containing cellulose through

various enzymatic processes and fermentation (Hu

et al., 2018). Bioethanol production from cellulose

waste has been developed, rice husk is one of the

renewable raw materials for bioethanol production

due to availability and cheap. The production process

of bioethanol from cellulose raw materials is very

complex so that it involves the preatretment process,

hydrolosis and fermentation (Nanssou et al., 2016).

Based on the Central Bureau of Statistics data, the

agricultural waste in Indonesia recorded 5,883,730

tons/year for corn waste, 439,657 tons/year for

pineapple skin waste, and 15.8 tons/year for rice

husk waste. Rice husk contains several organic

compounds, namely, lignin, cellulose, hemicellulose,

nitrogen compounds, vitamin B and organic acids and

contains inorganic compounds in the form of silica

(Ebrahimi et al., 2017). For rice husk used as raw

material for making ethanol can be seen in ﬁgure 1

below.

In table 1 there is a composition of cellulose,

hemicellulose and lignin from several agricultural

materials, it can be seen that corn stover contains

about 30-40% cellulose and lignin content 7-18,

where the lignin content can inhibit the hydrolysis

process.

According to (Cai et al., 2018) several stages

of the biomass process will be carried out to

Afdhol, M., Hidayat, F., Abdurrahman, M., Lubis, H., Wijaya, R. and Sari, N.

Utilization of Agricultural Waste to Be Bioethanol Sources as a Solvent on Parafﬁn Wax Crude Oil Issues.

DOI: 10.5220/0009366903150321

In Proceedings of the Second International Conference on Science, Engineering and Technology (ICoSET 2019), pages 315-321

ISBN: 978-989-758-463-3

315

Figure 1: Rice husks (Cai et al., 2018).

Table 1: Komposisi Cellulose, Hemicellulose dan Lignin

dari Lignocellulosic berbeda (Byadgi & Kalburgi, 2016)

Lignocellulosic Cellulose Hemicellulose Lignin

(%) (%) (%)

Miscanthus 40 18 25

Coastal 25 35.7 9-18

Corn Stover 35-40 17-35 7-18

Wheat Straw 30 50 15

produce ethanol, namely pretreatment, hydrolysis and

fermentation.

• Pretreatment, Biomass pretreatment is important

because to get high ethanol yield. The purpose

of the pretreatment is to open the ligninselulose

structure so that cellulose is separated from lignin

so that it is cellulose(Afdhol et al., 2019).

• Hydrolysis, Hydrolysis is the process of breaking

down existing polysaccharides in lignocellulose

biomass, namely cellulose and hemicellulose

which will be broken down into sugar monomers.

Cellulose hydrolysis that is done perfectly will

produce glucose. Hydrolysis can be carried out

chemically using acid or enzymatically. There

are several factors that inﬂuence the hydrolysis

process, namely the ﬁrst is carbohydrate content

of raw materials, pH of hydrolysis, hidrolysys

time, temperature and pressure.

• Fermentation, Fermentation is a microbial activity

in food ingredients so that the desired product

is produced. Common microbes involved in

fermentation are bacteria, yeast and mold. The

following are important factors that will affect the

ethanol yield and efﬁciency, that is on microbial

physiological conditions added to the media,

which depends on the optimal conditions for

speciﬁc growth of the microbes to be used and

environmental conditions during fermentation,

namely pH and temperature.

Solvent is a solution that is commonly used in the

petroleum world at various uses in their respective

ﬁelds and outside the world of petroleum as well as

many used solvents. In the table below is the use

of solvents as parafﬁn inhibitors or as an inhibitor of

parafﬁn formation, and the classiﬁcation of solvents

is also used as a reference for making solvents in the

research that will be conducted.

In table 2 there are several speciﬁcations of

solvents used as parafﬁn inhibitors with the type

of solvent parasol II, where this table is used as a

reference speciﬁcation for the manufacture of ethanol

type solvents.

Table 2: Solvent Speciﬁcations.

Parameter Information

Color Clear

Odor Aromatic

Physical State Liquid

Form Liquid

pH 9

Boiling Point 257

◦

F (125

◦

Flash Point 61

◦

F (16.1

◦

SG 0.8528

Density 0.8527

Oil production wells that are Pertamina EP Region

Sumatera Field Lirik by LS-124 (JOB PLP Lirik) has

parafﬁn properties with a fairly high wax content.

Parafﬁn crystals from production oil begin to form at

temperatures of < 180

◦

F at 100 ppm, at temperatures

below 180

◦

F it will increase to > 100 ppm, so that

forming wax crystals will be faster, the presence of

parafﬁn causes a decrease in ﬂow efﬁciency (FE) due

to damage formation so that the productivity index

(PI) also decreases. By injecting solvent (Xylene) and

surfactant oil production increases from 7 BOPD to

43 BOPD.

Therefore in this study a laboratory analysis was

carried out, namely making bioethanol using biomass

waste derived from rice husk, corn skin and pineapple

skin which will be processed so that it becomes

a solvent to be able to inhibitor the occurrence of

parafﬁn deposits. wet oil into wet water which is oil

that can ﬂow easily (Priyandono et al., 2007).

ICoSET 2019 - The Second International Conference on Science, Engineering and Technology

316

2 THE PROBLEM OF

DEPOSITION OF PARAFFIN

WAX

Parafﬁn is a mixture of hydrocarbon solid crystals

formed from linear or normal chains ranging from

to C

and consists of n-alkanes, iso-alkanes and

naphtenes. Wax is a high molecule of heavy parafﬁn

fraction from crude oil which can be separated below

from crude oil pouring points.

In general, there are also two types of wax

contained in petroleum. First, microcrystalline

wax consists of (n-alkanes) such as C

to C

and Secondly, amorphous waxes consist of mostly

isoparafﬁn and naphthalene such as C

to C

(Abdurrahman et al., 2018).

Deposits parafﬁn wax can be referred to as the

deposition of carbon material, which is insoluble

or dispersed by crude oil under normal conditions.

Normal conditions for maintaining crude oil in its

liquid form when temperature and pressure in the

reservoir area are in the range of 70 − 150

◦

C and

55-103 Mpa (Ridzuan et al., 2016).

Figure 2: effect of wax deposits shown above (a) measuring

drilling tubing, (b) intersection of the ﬂow pipe, and (c) on

the inside of the pipe.

Parafﬁn settles can also be caused by the loss

of volatile light in a crude oil, where the volatile

fraction in the crude oil acts as a solvent for wax.

When the ﬂuid of this mixture begins to cool, then

each component of the wax will separate (become

not dissolved) until ﬁnally the wax component which

has a high molecular weight will solidify. The event

where the ﬁrst wax crystals are formed at a certain

temperature is called the onset of wax crystallization

or better known as the cloud point or Wax Appearance

Temperature (WAT).

Up to 85% of world oil is affected by parafﬁn wax

which settles and solidiﬁes in the wellbore, in tubing,

perforations, pump circuits, and rods, and along the

ﬂowlines and pipe line transfer systems (Figures 2a,

2b, and 2c).

3 PARAFFIN WAX CONTROL

TECHNIQUES

Deposition of parafﬁn wax causes equipment failure,

upstream and downstream ﬂow congestion, and loss

of production, transportation capacity, and storage.

Because parafﬁn deposits are waxed, thousands

of wells are closed, many pipelines are clogged,

transport vessels are transported out of service, tanks

are locked, and reﬁnery equipment is closed at certain

times globally, all resulting in loss of income.

In other conditions technically removing

deposition of parafﬁn wax in the review includes:

Fused Chemical Reaction, Techniques, Heat

Applications, Chemical Additives, Magnetic Fluid

Conditioning (MFC) and Microbial Products

(Abdurrahman et al., 2018).

3.1 Fused Chemical Reaction

For this method, various chemical substances are

used to control waxy oil, such as diesel fuel, xylene,

toluene, and naphthalene. These substances are used

as solvent to dissolve wax deposit in reservoir and

increase the well productivity and reservoir condition.

There are two ways to inject solvent, continuous

injection and soaking injection. Continuous injection

is a method using a special injection pump, which set

up on the wellhead. The chemical is injected into

the wellbore through the annulus. For the soaking

method, a technique utilizing a small pump truck

dropped the chemical into the wellbore through the

annulus at a particular time (Abdurrahman et al.,

2018).

3.2 Tecniques

The practice of pigging is a way in which wax

removal is commonly accomplished in the ﬁeld. With

this method, deposited wax is techniques removed

by launching a pipeline pig along the line to scrape

wax from the walls as it is forced along by the oil

pressure. This, however, poses the risk of forming

a wax plug downstream from the pig as the scraped

wax accumulates and is compressed ahead of the pig.

In such an event the pipeline could be lost.

The use of bypass pigs tries to address this

problem. When the differential pressure across such a

pig becomes too high, because of the accumulation of

solid wax and debris ahead of it, the bypass pig allows

liquid to ﬂow through it and disperse the accumulated

solid ahead. However, there is always the danger that

if pigging has to be temporarily suspended due to

Mechanical failure, or that if the pigging frequency

Utilization of Agricultural Waste to Be Bioethanol Sources as a Solvent on Parafﬁn Wax Crude Oil Issues

317

for a pipeline is not correctly optimized, that the

result will be a stuck pig and sizable production losses

(Aiyejina et al., 2011).

3.3 Hot Water Method

Hot water is one of method used for maintaining the

reservoir temperature. Furthermore, hot water which

injected into the wellbore slow down the deposition

wax process. It can be applied during completion

and production. During completion, hot water is

circulated into the annulus using coiled tubing. Then,

tubing string is heated to maintain the temperature

above the pour point. In terms of production, hot

water is being used along with water injection to

maintain the pressure and temperature. The hot

water collected at the manifold for certain purposes.

This technique can also be combined with chemical

method in order to prevent the appearance of wax in

the wellbore (Abdurrahman et al., 2018).

3.4 Biological Treatment

Biological wax removal methods have also been

studied in recent years by researchers such as who

developed systems of parafﬁn-degrading bacterial

consortiums with nutrient supplements and growth

enhancers for controlling parafﬁn deposition in the

tubular and well bore region and in surface ﬂow

lines. Their results showed that their systems were

highly effective, eliminating the need for repeated

scrapings of wax over a period of several months.

These methods are especially important because, if

successfully implemented, they have the beneﬁt of

providing continuous control of wax deposition in

pipelines through constant biodegradation, rather than

just providing a very temporary ﬁx (Aiyejina et al.,

2011).

3.5 Microbial Method

The subject of this method is to decrease the

cloud point or appearance of wax as apparent

molecular weight of crude oil. This method used the

microorganisms that alter the composition of crude

oil through bio-degradation. Crude oil in contact with

the microorganism (such as Pseudomonas aeruginosa,

Bacillus subtillis, and Bacillus licheniformis) may be

degraded directly or break the long chain into short

chain.

4 RESULT AND DISCUSSION

Bioethanol making there are several important aspects

that must be considered such as sample size, acid

concentration, reducing sugar content, stirring speed ,

temperature and fermentation time this can affect the

ethanol content that will be produced.

So in this chapter we will also compare the effect

of parameters that affect the results of ethanol from

the raw materials of rice husks and corn cobs. The

following is a detailed explanation of each of the

parameters from each raw material.

4.1 Corn Cobs

During the hydrolysis process, hemicellulose acid

is converted to cellulose. The results of the acid

hydrolysis process showed that the smaller the size

of the corn cobs particles (the bigger the mesh), the

better the hydrolysis of the acid. This is shown

in Figure 3, the hemicellulose level decreased with

the smaller size of the corn cobs particles and the

cellulose content increased with the smaller particle

size.

Figure 3: The relationship between material content and

particle size during the process acid hydrolysis for 24 hours

(Soeprijanto and Prasetyaningrum, 2008).

The effect of particle size on enzyme/acid

hydrolysis on glucose conversion is shown in Figure

4. The results showed that the smaller the size of

the corn cob particles, the greater the conversion of

glucose obtained, because the small-sized particles

resulted in having a large contact area between corn

cob particles and enzymes/acid so that the process

of hydrolysis of enzymes/acid to cellulose to glucose

became larger and causing cellulose conversion to

increase glucose. The increase in conversion to

glucose is also followed by an increase in the dose

increase of the enzyme/acid added. With the addition

ICoSET 2019 - The Second International Conference on Science, Engineering and Technology

318

of the highest dose of enzyme 50 ml and various

particle sizes (25, 50, 100 mesh), the conversion of

cellulose to glucose increased by 43. 19%, 45.69%

and 51.01%. So that the highest conversion that can

be achieved is 51.01% using the size of 100 mesh corn

cobs and 50 ml enzyme doses.

Figure 4: The relationship between glucose conversion and

particle size (Soeprijanto and Prasetyaningrum, 2008)

in the hydrolysis process, protons H

from

HCL compounds will convert ﬁber groups from raw

materials into free radical groups. the free radical

group will then be related to the OH

−

of H

and produce glucose. when the need for H + from

HCL is sufﬁcient to form radical groups from the raw

material, the glucose produced is maximal.

As well as the longer the fermentation time, the

higher the ethanol produced. this is because the

longer the fermentation time, the more glucose is

reduced to alcohol, especially ethanol, but of course

there is a maximum limit of microbial activity. It can

be seen from the result of the graph in ﬁgure 5 below

(Fachry et al., 2013).

4.2 Rick Husk

Rice husk has a lot of cellulose content which is

around 30% but the lignin content in rice husk

is also large, which is around 15% where lignin

binds strongly to carbohydrates, so it can inhibit the

hydrolysis of cellulose by enzymes. To obtain ethanol

from rice husk, the pretreatment stage is needed. The

pretreatment stage is done to break the lignin bonds,

so that cellulose can be hydrolyzed by enzymes that

can produce glucose (Inggrid et al., 2011). One of

the pretreatments that can be done is by using alkali

peroxide, so that the pretreatment process also adds to

costs in the ethanol production process.

Figure 5: Effect of HCL molarity on ethanol levels at

various fermentation times (Fachry et al., 2013)

At this stage, determining the effect of stirring

speed and determining the effect of H2O2

concentration and temperature. Experiments on

the effect of stirring speed using 0% H

and 2.5%

at a temperature of 35

◦

C with variations in stirring

speed 0, 100, 150, 200, and 300 rpm. Experiments

to determine the effect of H

and temperature

concentrations were carried out with variations in

concentrations of 0%, 2.5%, 5%, 7.5%, and

10% and temperature variations of 25

◦

C, 35

◦

C, and

◦

Experiment on determining the effect of stirring.

Stirring uses a paddle because it has the largest

cross-sectional area, so that with a small stirring speed

can provide a great stirring effect.

When H

2.5% 150 rpm cellulose levels should

increase because the levels of lignin drop. Because,

on a 100% basis when lignin levels decrease (there

is lost lignin), the cellulose level rises (even though

the amount is ﬁxed). However, in the experiment,

the cellulose content dropped because when the

lignin bond was tried to be broken, there was

some cellulose which was damaged. the effect

of variations in stirring, H

concentration, and

temperature is easier to see when analyzing glucose

levels because the changes are greater than changes

in lignin and cellulose. Moreover, in the manufacture

of bioethanol, which has an important role is the level

of glucose.

Based on observation of ﬁgure 6 and ANOVA

statistical test, stirring has an effect on the level of

lignin. At a speed of 150 rpm the level of lignin is

Utilization of Agricultural Waste to Be Bioethanol Sources as a Solvent on Parafﬁn Wax Crude Oil Issues

319

lowest because there is no dead zone (at 0 and 100

rpm) and vortex (at 300 rpm), so that radical OH

contact with rice husk is good. Good contact results

in more broken lignin bonds.

ANOVA statistical test results it can be ascertained

that the temperature and H

concentration have

an effect on the glucose level produced, the

higher the concentration of H

, the higher the

glucose produced, but decreases at a 10% H

concentration. Meanwhile, changes in operating

temperature from 25

◦

C to 45

◦

C do not have a large

effect on cellulose levels.

Understanding wax aging mechanisms is also very

important to fully understanding the process of the

formation of wax deposits in pipelines. Furthermore,

understanding these mechanisms and predicting the

CCN of particular crude oils would be helpful in

determining what chemical inhibitors would be most

effective for preventing wax build-up in pipelines

carrying those oils.

The continuing research into methods of

inhibiting wax deposition and removing deposits has

the potential of making the maintenance of crude oil

pipelines signiﬁcantly easier, as it becomes easier

to optimize pigging frequency, to determine the

minimum pressure required to restart gelled lines,

or even to avoid the need for constant wax removal

procedures by ﬁnding a way to costeffectively

implement a promising method of control such as the

use of polar crude oil fractions or biological removal

measures.

Initial testing of oil containing parafﬁn wax is very

important to determine the wax content contained in

oil and the temperature at which wax begins to form.

then testing was carried out to test the oil containing

parafﬁn wax after adding a solvent to it, so these two

tests were conducted to see the effectiveness of the

solvent to overcome the problem of parafﬁn wax.

As for the tests carried out to identify the content

of parafﬁn wax in oil, which is cloud point testing

(ASTM D5771), cold point testing (ASTM D6371)

(Products & Products, n.d.) and pour point testing

(ASTM D97) (Methods & Oil, n.d.), this parameter

can be used as a reference whether the solvent mixed

with oil containing parafﬁn wax can be handled

properly or not. and also other supporting tests

such as density (ASTM D1298) (Standard, n.d.),

speciﬁc gravity (ASTM D1250) (Guide, 2004) and

API (ASTM D287) and viscosity (ASTM D445)

(Viscometers et al., 2009). where all these parameters

are the reference to the success of the solvent in

dealing with parafﬁn wax.

5 CONCLUSIONS

This work shows how the process of making

bioethanol from agricultural waste with optimal

conditions such as particle size, enzyme / acid

concentration, reducing sugar content, stirring speed,

temperature and fermentation time and also in this

work provides another alternative in overcoming

the problem of oil containing parafﬁn wax using

bioethanol which produced from agricultural waste

so that it can prevent environmental damage and

provide a more efﬁcient cost alternative in dealing

with parafﬁn wax deposits.

ACKNOWLEDGEMENTS

A Great Thanks To Universitas Islam Riau and

Petronas Technology University for funding with

number 469/KONTRAK/LPPM-UIR-9-2018 For

Support In Writing This Paper.

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