ASSESSING THE TOTAL PETROLEUM HYDROCARBON IN CRUDE OIL WASTE TREATED BY THERMAL DESCRIPTION

ASSESSING THE TOTAL PETROLEUM HYDROCARBON IN CRUDE OIL WASTE(S) TREATED BY THERMAL DESCRIPTION UNIT

Table of Contents

Abstract

Chapter One:      Introduction

1.1 Background of study

1.2 Statement of the problem.

1.3 Purpose of the study

1.4 Objectives of the study

1.5 Research Questions

1.5 Significance of the study

1.6 Limitations of the study

Chapter Two:      Review of Related Literature

2.1     Petroleum hydrocarbon

2.1.1  Chemistry of Petroleum Hydrocarbons

2.1.2  Alkanes

2.1.3  Alkenes

2.1.4  Aromatics

2.1.5  Homologous Series

2.1.6  Isomers

2.2     Petroleum hydrocarbon pollution

2.2.1  Anaerobic Degradation

2.3     Thermal desorption

2.3.1  How does thermal desorption work

2.3.2  Why consider thermal desorption

2.3.3  Will it work at every site

2.3.4  Ex situ TD

2.3.5  In situ TD

2.1.7 Applications of TD

Chapter 3: Material and Methods

3.1.    The Thermal desorption unit (TDU) Facility

3.2     Waste Treatment Procedure

3.3     Chemical Characterization of Waste

3.4     Pollutant Gas Emissions

3.5     Statistical analysis

Chapter 4: Data Analysis and Interpretation

4.1     Characteristics of Drill Cuttings

4.2     Efficiency of Treatment of Drill Cuttings

4.3     Gaseous Pollutant Emissions during Treatment

4.4     Discussion

Chapter Five:      Conclusion and Recommendation

References

Abstract

This study investigated the treatment efficiency of oil-based mud contaminated drilling waste using the Thermal Desorption Unit (TDU) technique, and also monitored pollutant gas emissions associated with the process. Composite drilling waste feedstock samples were characterized. Heavy metals were determined spectrophotometrically while total petroleum hydrocarbons (TPHs) (benzene, ethyl benzene, toluene, naphthalene and xylene) were determined chromatographically. Digital air monitors and a high volume gravimetric air filter sampler were used to monitor gaseous emissions. Variation plots and Student’s t-test were used to analyze data. The concentrations of the contaminants decreased significantly after treatment (t=0.032) at P<0.05 from 21520.00 to 71.61 mg/kg (TPHs), 0.001 to 0.0005 mg/kg(benzene),7.55to0.001mg/kg(toluene),3.64to0.001mg/kg(xylene)and5.80to0.001mg/kg(naphthalene). Very high treatment efficiencies of 99.67, 99.99, 99.97, 99.98, 99.47, 97.48 and 87.13% were recorded for TPHs, toluene, xylene, naphthalene, V, moisture contents and electrical conductivity. Gaseous emission levels were below regulatory limits, even as relatively highest emissions were recorded for suspended particulate matter (15.0 ± 0.2 mg/m³), and least emissions for CH₄ (0.39 ± 0.1 mg/m³).

CHAPTER ONE

INTRODUCTION

1.1 Background of study

The demand for oil, gas, and other energy sources are growing dramatically with the worldwide energy consumption that projected to increase by 37 percent in 2035. Rising demand driven by world’s population which is predicted to increase by 25 percent in the next 20 years. Oil and gas exploration and production (E and P) activities aside from being a necessity, are responsible for various environmental accidents around the world, e.g. Oil spills during transportation and distribution, waste from the E and P operations in the form of oil sludge, waste drilling fluid/mud, waste treatment plant residue (oil separator, oil catcher, dissolved air flotation), leakage from floating storage, tankers, storage tanks, residue from cleaning activities, work over wastes, well completion, treatment, and stimulation fluid, produced water and finally offshore wells drilling leakage as well as the distribution of oil spilled from the well to the tanker and from the ship to the mainland. Inadequate treatment of those wastes can threaten the human health and safety as well as the environment.

Oil spills are possibly the highest source of sea and river pollution. Generally, oil is accidentally discharged during extraction, distribution, storage, and usage. The British Petroleum (BP) explosion on 20th April, 2010 in the Gulf of Mexico covered 790km of shoreline within 36 months, which resulted to several casualty’s (Welch and Joyner,2013; Polson,2011).The discharges of 260,000 barrels by Exxon Valdez in the gulf of Alaska, 24,000 barrels spills in River Monongahela due to storage tank rupture, oil tanker failure in the Strait of Malacca, the 978 Amoco Cadiz super tanker accident; Arabian Gulf incidence in 1991as a result from the release of huge barrels of oil in the operation Desert Storm (Kapoor andRawat,1994), the Prestige oil tanker incident that resulted to 12000 tonnes of oil spilled in Galicia, Spanish coastlines in 2002, are but a few cases of oil spill accident in the previous years. It can be stated in recent years that the trend has changed greatly. About 22 oil spills incidence along the Norwegian coastline alone in the last two decades has been reported (wwf.no/dette). Oil spill has a great negative influence on the ecosystem by putting the marine lives at high risk. However, the extent of risk is dependent on the type and volume of the oil in addition to other abiotic factors such as the sensitivity limit of the marine habitat. Oil spill on river or sea envelopes the water surface and consequently, shields the diffusion of sunlight that enhances photosynthesis. Aquatic lives rely mainly on Phytoplankton and seaweed for existence. Majority of crude oil discharge occurred in the water ways.

About 5millions tons of unrefined oil products are transported per annum averagely across the ocean globally (Anisuddin et al., 2005, Fominyen, 2010). Oil consists of wide range of organic (hydrocarbon) based constituents which might be crude oil, refined, edible and non-edible oil. However, crude oil may contain other elements such as sulphur, hydrogen sulphide and oxygen (Wang and Fingas, 2003). Oil spill effects have attracted several researchers from different disciplines involving petroleum engineering, biology, environment engineering, marine engineering, chemical engineering, materials engineering (Espeda and Johannessen, 2000; Stephanie, 1994; Mario, 2000; Vendrell, 1993; Price, 1991; Fingas and Fieldhouse, 1994; Fingas, 1995). However, sustainable oil clean up approach is still a huge and challenging task due to high cost and environmental impact of the current practices.

The traditional techniques that have been used over time include; the use of chemical dispersants, containment (oil booms), mechanical recovery (skimmers and separators) and bioremediation. The strategies and efforts for cleanup activities depend upon various factors such as water temperature, nearness to shoreline, spill volume, oil type and density, waves, weather, currents and response speed (Graham, 2010). These factors create limitations, which possess challenges in recent years. The need for eco- friendly and cost effective natural sorbents cannot be overemphasized in recent times. Diverse agricultural products such as peat, leaves and wood products have been employed. Cotton, straws, kenaf, corn cob, wood fibre, milkweed floss, peat moss, kapokfibre was reported (Choi and Cloud, 1992; Scharzberg, 1971). These materials for absorbents need to fulfill several criteria before they can be considered to be viable oil spill clean-up absorbents. The material should be hydrophobic and oleophilic, possess high rate of uptake and retention, and be able to release absorbed oil (John, 2001). The hydrophobicity and oleophilicity enhance oil absorption capacity with little or no water uptake. The high uptake capacity facilitates large amount of oil pick up relative to the weight of material. The high rate of uptake shows that the material absorbs the oil quickly. The retention over time confirms that oil does not leak from the material after absorption. On the other hand, it is also essential to cheaply and easily remove absorbed or adsorbed oil from the material; otherwise, it becomes cumbersome and inefficient in the long run. Preferably, the material should be reusable and biodegradable (McLeod and McLeod, 1974).

Soil contamination by petroleum and other heavy hydrocarbons is a major global environmental problem. For example, over 100 000 barrels of oil are spilled on average every year in the US, contaminating soils with a range of petroleum hydrocarbons, from crude oils and sludge to refined fuels such as gasoline. While a lot of remediation technologies exist, technologies that can quickly treat soils contaminatedwith a wide range of petroleum hydrocarbons are especially desirable.

Quite frequently, the selection of remediation method is driven by considerations that require expeditious completion (e.g., compliance issues, impending property transactions, and impacts on third-party property). Thus, thermal technologies fill an important niche in petroleum hydrocarbon remediation.

Thermal desorption is an environmental remediation technology that utilizes heat to increase the volatility of contaminants such that they can be removed (separated) from the solid matrix (typically soil, sludge or filter cake). The volatilized contaminants are then either collected or thermally destroyed. A thermal desorption system therefore has two major components; the desorber itself and the offgas treatment system. It is worthy to note that thermal desorption is not incineration.

This paper is focused on thermal desorption. In the bid to proffer a suitable means of treating crude oil waste, this paper set out to assess the amount of petroleum hydrocarbon in crude oil waste that is treated by the process of thermal desorption.

1.2 Statement of the problem.

The demand for oil, gas, and other energy sources are growing dramatically with the worldwide energy consumption that projected to increase by 37 percent in 2035. Oil and gas exploration and production (E and P) activities aside from a necessity, are responsible for various environmental accidents around the world. Oil spills seemed to be the highest sea and river pollution.

Soil contamination by petroleum and other heavy hydrocarbons is a major global environmental problem. Despite the fact that a range of remediation technologies there is still need for technologies that can treat effectively crude oil wastes. Hence, this project is focused on assessing the total petroleum hydrocarbon in crude oil waste(s) treated by thermal desorption unit.

1.3 Purpose of the study

The purpose of this study was to assess the total petroleum hydrocarbon in crude oil waste(s) treated by thermal desorption unit.

1.4 Objectives of the study

The study was guided by the following objectives: –

1. To determine the total petroleum hydrocarbon in crude oil waste that is treated by thermal desorption.
2. To determine the efficiency of the thermal desorption unit in the process of crude waste treatment.

• To determine the amount of gas pollutant emissions accompanied with the process.

1. To examine the concentration of petroleum hydrocarbon in crude waste(s) before and after treatment.

1.5 Research Questions

This study was guided by the following research questions: –

1. What is the total amount of petroleum hydrocarbon treated by the process of thermal desorption?
2. What is the efficiency of the thermal desorption unit in the process of crude waste treatment?

• What is the amount of gas pollutants involved in the process?

1. What is the variation in the concentration of petroleum hydrocarbon present before and after thermal desorption?

1.5 Significance of the study

This study sought to determine precisely the total amount of petroleum hydrocarbons treated from crude waste by thermal desorption. This study will establish the efficiency of the thermal desorption unit in the process of remediation. The information that will be provided by this study will be useful to clean up agencies who will have to tackle oil spills in the future.

1.6 Limitations of the study

There are different forms of crude waste. We haveoil spills during transportation and distribution, Waste from the E and P operations in the form of oil sludge, waste drilling fluid/mud, Waste treatment plant residue (oil separator, oil catcher, dissolved air flotation), Leakage from floating storage, tankers, storage tanks, Residue from cleaning activities, Work over wastes, well completion, treatment, and stimulation fluid, Produced water, Offshore wells drilling leakage as well as the distribution of oil spilled from the well to the tanker and from the ship to the mainland.

The researcher was unable to tackle all the forms of crude waste in existence. As a result, this project is limited to waste from drilling mud.

ASSESSING THE TOTAL PETROLEUM HYDROCARBON IN CRUDE OIL WASTE(S) TREATED BY THERMAL DESCRIPTION UNIT

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