Nigeria's potential as a major global gas supply and utilisation hub is high. Available statistics show that even without a dedicated gas exploration regime, Nigeria has at present the 7th highest proven gas reserves in the world, with 183 Trillion Cubic Feet. This is gas that has been discovered in the process of exploring for petrol. We also have the potential of realising over 600 TCF, which would place us at 4th position worldwide.
The FGN believes that in order to realise and sustain this potential, the structure of the gas sector must support continued cost effectiveness in supply of all markets (domestic, regional and export), scalability of capacity and above all, must be fully liberalized and market driven. Hence, the Nigerian Gas Master-plan (NGMP) has been developed and presented to investors since 2008. Among others, this Master plan proposes franchising three major Gas Processing Facilities (CPFs), all located in the Niger Delta region – Western Delta, around the Forcados area; Central Delta, north of Port Harcourt; and South East Delta, between Uyo and Calabar. Each of these Facilities is expected to process at least 1000 MMscf/d (standard cubic feet per day), but in fact 2,500 MMscf/d of raw gas. Largely overlooked, however, is the fact that significant amounts of toxic waste will be generated on a daily basis.
The purpose of this presentation is to show that from conception to full design, this Master-plan so far fails to take into consideration the safe disposal of, and probable environmental hazards associated with, these toxic by-products and after-effects of the dehydration of gas using chemicals. From all presentations to investors in the industry it has become clear that the logic of economic benefits to be gained predominates, and environmental consequences are not touched on. Apparently there is the fear of scaring off investors when environmental aspects are brought into the equation. For instance, nowhere in it has consideration been given to human persons that might be affected and impacted by this budding gas industry.
The toxic by-products of this process, as I shall demonstrate, are many and varied, and may bear down directly on the human, animal and aquatic populations in the Niger Delta. My plea is for the inclusion in the overall architecture of the Master plan, and its implementation, a full Life-Cycle Cost (LCC) that indicates not only the initial Capital Expenditure (CAPEX) for building the plants, but also the Operational Expenditure (OPEX) from conception to final removal of these facilities when their lifespan is exhausted. I shall suggest that it makes more economic sense to invest now in available clean technology than be saddled with the burden of disposing toxic wastes later on.
When extracted from the ground, natural gas usually contains significant quantities of water and other water-based and organic compounds. This is called 'wet gas”. During production, transportation and processing, changes in pressure and ambient temperature can lead to water condensation, ice and/or gas hydrate formation, or corrosion in the facilities. Dehydration, therefore, is one of the major processes in any gas processing plant, and Ethylene Glycol (EG) has been the chemical of choice for this industrial process since the 1960s.
EG on its own is a common industrial chemical which has no extreme hazardous properties. Due to its hygroscopic (water-absorbing) properties, its natural affinity for hydroxyl (-O-H-), or water based functional groups, EG is an economical way of stripping the gas of its associated water. Water (H2O), in the chemical structure H=O-H, where the O-H is the chemically active part, will be chemically bonded to the EG. Based on this, the lean EG will absorb water in a counter-current contact with the wet gas and consequently dry it, thanks to its hygroscopy.
In a gas processing facility this is done in a so-called glycol contactor. The dry gas rises up and is conducted through pipes for use elsewhere, or is liquefied for easy transportation; the associated water, now heavy with EG is, on the other hand, routed from the bottom of the contactor and removed. The process could well have ended here, but in order to avoid a permanent supply of fresh EG, operators have developed a re-generation process for the 'used' or water-heavy EG. The process itself is simple: the used or heavy EG is collected and heated to its boiling point in this system, and in that way the water (plus other associated -OH compounds) is released from the EG (i.e., boiled off).
This water, now in vapour phase, is vented into the atmosphere via a stack or chimney, and what remains is almost pure EG, which can once again be returned and reused in the process. The entire process has a good efficiency rate, because common practise shows the requirement of fresh EG is limited to 5-10%. So, apparently this 5-10% is lost somewhere in the process, and this happens during each and every sequence, continuously. However, 90-95% of EG is saved, and is re-circulated via the contactor to the MEG-Regeneration Unit all over again. (Note some of the acronyms used in the literature - MEG: mono-ethyl-glycol, DEG: di-ethyl-glycol, TEG: tri-ethyl-glycol, and TETRA EG: Tetra-ethyl-glycol).
The problem, however, is that in boiling one adds heat (energy) to the system containing the used EG, which has already bonded with water. But EG also bonds with other components that behave similarly with water: components that also have an active -OH functional group, e.g. phenol, alcohol, etc., and consequently react similarly. These include also organic molecules, small ones like alcohols, but also bigger ones like phenols, etc.
In other words, any chemical with an end-standing functional –O-H group could possibly react with EG in this process, in a similar way as water does. As energy levels are high due to the heating, the resulting mix will contain many variations, subject to nature's random occurrence. So a part of the loss, an estimated amount of 80% of it, will leave the regeneration system as a vapour, and a part will precipitate and settle in the system. The vapour part is referred to by process technologists as BTX, referring to Benzene-Toluene-Xylene. These BTX compounds are naturally very toxic, and leave the EG regeneration-system with the water-vapour vented into the atmosphere. The remaining 20% settles down in the MEG-regen-unit and forms a carcinogenic black tar residue, continuously. When the vented vapour (i.e. the 80%) ultimately cools off through ambient temperatures, the gaseous compounds may condensate and/or precipitate, and disappear into the groundwater, which may be in use for human consumption.
BTX-compounds can go through the human skin, so breathing, bathing and washing will do the damage equally. One does not even need to drink the contaminated water to be affected. Breathing is not a pleasant option either, because the smell one perceives when approaching a MEG-regen-unit is very strong and penetrating, leaving one with the unmistakable impression that this cannot be healthy. The black tar, on the other hand, accumulates in the re-gen-system. At a moment in time, say bi-annually, this has to be removed lest it affect the efficiency of the system. The tar is extremely carcinogenic.
Once again, to regenerate the EG, one adds (heat) energy to the system. But this energy is also sufficient to have EG react with salts and create fur-like deposits in the boiling system, just like one gets magnesium and calcium-based deposits on a cooker/boiler when (hard) water is brought to boiling point. This energy can also cause other -OH-molecules to react to/with other substances as well, which may have accompanied the wet gas from the earth. Here a special group of so-called aromatic compounds comes to mind. These have an exceptionally reactive end-group. Phenol is the -OH-variant.
The toxicity of toluene can be explained mostly by its metabolism. As toluene has very low water solubility, it cannot exit the body via the normal routes (urine, feces, or sweat). It must be metabolized in order to be excreted. Xylene exhibits neurological effects. High levels from exposure for acute (14 days or less) or chronic periods (more than 1 year) can cause headaches, lack of muscle coordination, dizziness, confusion, and imbalance
Studies of unborn animals indicate that high concentrations of xylene may cause increased numbers of deaths, and delayed growth and development. The principal pathway of human contact is via soil contamination from leaking underground storage tanks containing petroleum products. Humans who come into contact with the soil or groundwater may become affected. Use of contaminated groundwater as a water supply could lead to adverse health effects.
Note that the compounds so far named are formed during the required boiling process to regenerate EG, and it is the lost 5-10% that often reacts with other micro-molecules in the natural gas, increasing their boiling point, and making them impossible to break down. These will therefore ultimately remain as residue: a black carcinogenic tar that can only be incinerated at very high temperatures. The problem: nature uses process kinetics with the implication that adding energy like heat will result in a new stable compound at a higher energy level, and this means, to change the new compound, one must add even more energy. How much energy can humans generate in order to break down the stable compounds they might ingest/assimilate? Very little, indeed.
3. Implications for Human Beings
Now the human body can provide a limited amount of chemical energy to deal with strange chemical compounds, normally sufficient to deal with normal natural environmental compounds with average energy levels required to break them down. But if the body cannot provide sufficient energy, the high-energy-level compound stays untouched and is stored in fat-layers in the body, or worse: in the organs. And sometimes, these chemicals remain active and can react with internal body-compounds like enzymes and proteins and amino acids, which happen to be the basic building block of a substance called de-oxy-ribo-nucleic-acid, better known as DNA.
Once the DNA starts to replicate via a duplication kinetic called t-RNA-polymerase, a chemical reaction triggered by an enzyme, it will duplicate the amino acids in sequence, and also affect any changed amino acid, which could ultimately cause genetic defects in humans as this duplication process is sensitive and fragile. These defects may be simple and of no consequence if they are not on a key-functional part of the DNA. But who can guarantee this? If, however, they happen to be on a key-part, serious defects can occur, and these will ultimately result in defects at birth, immediately affecting the health and ability of the new born one.
It must be borne in mind that our purpose is not to oppose the Federal Government's intention to exploit our vast resources of natural gas, as this is necessary to meet the cash-calls for reaching our developmental goals. At the same time, we know that development that does not factor in possible consequences for human beings is a contradiction in terms.
This is why we wish to reiterate that all the above mentioned toxic effects arise only when EG is used in the process of gas dehydration/purification. But there is now tested technology that does not require the use of EG, a good example being that in use right now in the Afam Gas Plant, which feeds Afam Power Station. My point is, since we know this technology exists, and is already being used at least in one gas plant in Nigeria, why not replicate it in others as well? Prevention, as they say, is better than cure; so why do we not choose to avoid the toxicity of BTX wastes by making a safe technology choice now, rather than be saddled with the social and environmental impact, and the possible political fallouts of unsafe disposal of these carcinogenic wastes? So far the only reason militating against this is the economics of cost-saving and profitmaking. But I do not find this convincing, because if one looks seriously at the equation, we must base our economic model on LCC, life cycle cost.
This means that the cost of a project must be calculated from the day of conceptual design to the moment of dismantling the plant, including operational expenses OPEX (i.e. proper waste removal during operation) and removal expenses (i.e. proper waste removal after operation), and not only capital expenditure CAPEX, or the initial cost for setting up a gas processing unit. My view is that if you take all the removal/disposal costs into consideration, even apart from the related environmental, social and political problems, new chemical-free technology will prevail in advantage over EG-dependent processes.
While we see the need for these operators to be given the freedom of choice to design and build their gas processing plants in the most economical way, we also wish to urge the government to be firm in dictating in as clear terms as possible, that:
o the use of environmentally friendly technology will prevail over the plant economics of the various operators;
o there will be a stringent regime of environmental regulations, including penalties to deter and/or punish environmentally unfriendly disposal of toxic wastes;
o the economics of waste disposal should be taken into account in the economic comparison of the total LCC (life-cycle cost) of the various technology concepts, in this way allowing a fair chance for new chemical-free technologies with different CAPEX/OPEX.
Nigeria cannot afford to produce its resources at the cost of its environment. China is a guiding example of nations that sought quick economic growth, and overlooked possible environmental consequences. They are living with those consequences now, and possibly paying a high price for the health of its citizens and remediation of their despoiled environments. That is one way the Nigerian economic growth strategy should not follow, because Nigeria is growing democracy whereas China can afford to brutalise its population into silence and acquiescence. Short term economics may suggest high revenues in the immediate and middle term future, but these revenues cannot meet the long term cost of cleaning the waste once they enter into the ecological system. As the people have no option to relocate, since no such space is available in Nigeria, preserving what we have is the only way forward.
GASIN, in the course a desk research has identified some international standards being applied in the exploration, processing and distribution of natural gas. Some of the standards are among the basic requirements for the establishment of natural gas processing facilities while others are codes of practice that are applicable to the oil and gas industry. The Nigerian government, through the Department of Petroleum Resources (DPR) in 1991, has consulted a number of international standards, stepped them down and drafted general guidelines regarding environment safety in the course of oil and gas exploration. This national standard is called “Environmental Guidelines and Standards for Petroleum Industry in Nigeria (EGASPIN).” Thus, in addition to the international standards, the EGASPIN is a rich document that covers various environmental safety recommendations for the operating protocols in the petroleum industry in general. Unfortunately, it does not say much about gas, as such. These international standards include:
I. ASME B31.8 for Gas Transmission and Distribution Systems (ASME means American Society of Mechanical Engineers)
This code or standard was developed under procedures accredited as meeting the criteria for American National Standards and consists of many individually published sections, each an American National Standard.
The Code sets forth engineering requirements deemed necessary for the safe design and construction of pressure piping. To the greatest possible extent, the code requirements for design are stated in terms of basic design principles and formulas. These are supplemented as necessary with specific requirements to ensure uniform application of principles and to guide selection and application of piping elements. The code prohibits designs and practices known to be unsafe and contains warnings where caution, but not prohibition, is warranted.Although safety is the basic consideration, this factor alone will not necessarily govern the final specifications of any piping system.
It is this standard that states that when corrosive gas is transported, provisions shall be taken to protect the piping system from detrimental corrosion and that gas containing free water under the conditions at which it will be transported shall be assumed to be corrosive, unless proven to be noncorrosive by recognized tests or experience (ASME B31.8, Section 863.1).
“No pipeline, regardless of wall thickness, is impervious to failure; attempts to characterize thick-walled pipes as somehow invincible or better than thin-walled pipes appear to be incomplete efforts to deceive an uninformed government, public, or management team” (Accufacts Inc., 2005). A number of design issues can lead to pipeline ruptures just as in the case of San Bruno rupture which was caused by a poor longitudinal seam weld on a short pup that could not withstand ductile tear (high pressure) and pressure fluctuations (pressure cycling) (Accufacts Inc., 2012) .
ii. ISO 1400: Environmental Quality Management (ISO means International Standardization for Organizations)
ISO 14001 is the internationally recognized standard for the environmental management of businesses. It prescribes controls for those activities that have an effect on the environment. These include the use of natural resources, handling and treatment of waste, and energy consumption. Implementing an Environmental Management System is a systematic way to discover and control the effects a company has on the environment. Cost savings can be made through improved efficiency and productivity. These are achieved by detecting ways to minimize waste and dispose of it more effectively and by learning how to use energy more efficiently. It verifies compliance with current legislation and makes insurance cover more accessible.
iii. API Standard 2510 Design and Construction of LP Gas Installation at Marine and Pipeline Terminals, Natural Gas Processing Plants, Refineries, Petrochemical Plants and Tank Farms. (API means American Petroleum Institute)
This standard provides minimum requirements for the design and construction of installations for the storage and handling of lique?ed petroleum gas (LPG) at marine and pipeline terminals, natural gas processing plants, re?neries, petrochemical plants, and tank farms. The standard takes into consideration the specialized training and experience of operating personnel in the type of installation discussed. In certain instances, exception to standard practices are noted and alternative methods are described.
The Nigerian Gas Master Plan shows that natural gas will be transported both in gaseous phase and liquid phase as Liquefied Natural Gas (LNG) (NNPC, 2007) . Thus, the handling of these products at production sources in Niger Delta is a critical issue.
iv. API Recommended Practices 520 and 521 for pressure-relieving and depressurizing systems.
This recommended practice applies to the sizing and selection of pressure relief devices used in refineries and related industries for equipment that has a maximum allowable working pressure of 15 psig (103 kPag) [psig: pound force per square inch gauge; kPag: kiloPascal gauge] or greater. The pressure relief devices covered in this recommended practice are intended to protect unfired pressure vessels and related equipment against overpressure from operating and fire contingencies.
Generally, natural gas pipelines have maximum allowable pressure and pressure-relieving systems are installed to absorb and reduce excess pressure. In our target communities, where pipelines run very close to homes, it is necessary that we understand the provisions of this standard in order to be able to assess and advocate for the necessary installations that will arrest pressure-related incongruities in natural gas processing and transmission. It is known that explosions that occur in a high-pressure pipeline are devastating. This is the case of the explosion that occurred in Carlsbad in 2000, where a high-pressure gas pipeline ruptured, exploded and led to the death of twelve (12) civilians (National Transportation Safety Board, 2002) . According to Accufacts Inc. (2005) , when reviewing any pipeline system, it is important to evaluate the downstream and upstream facilities to assess their potential to place the interconnecting pipeline system under high pressures that can result in high stress levels and cause anomalies in the pipe to fail. Any downstream facility design that can close or block in the pipeline, or that overemphasizes reliance on electronic safeties to prevent overpressure events, needs to be carefully scrutinized as the potential for such electronics to fail, when most needed, can be very high and the consequences severe.
v. National Fire Protection Association Standards No. 59A
This standard applies to the: facilities that liquefy natural gas; facilities that store, vaporize, transfer, and handle liquefied natural gas (LNG); the training of all personnel involved with LNG; the design, location, construction, maintenance, and operation of all LNG facilities.
From the blueprint of Nigeria gas master plan, there will be three (3) gas processing facilities to be located in the Niger Delta. GASIN, if properly trained, will exploit the knowledge of this standard, to advocate for installations that are in accordance with the NFPA standard during the implementation of the gas master plan, because, the best safety strategy is applied at the design and installation stage.
vi. Liquefied Petroleum Gas Safety Code of Safety Practice.
The industry benchmark for safe LP-Gas storage, handling, transportation, and use. This code applies to the storage, handling, transportation, and use of LP-Gas. Liquefied petroleum gases (LP-Gases), as defined in this code, are gases at normal room temperature and atmospheric pressure. They liquefy under moderate pressure and readily vaporize upon release of the pressure. It is this property that permits the transportation and storage of LP-Gases in concentrated liquid form, although they normally are used in vapor form.
The Nigerian GMP highlights domestic utilization of gas as one of the key ways to utilize the nation's gas resources. Also, the use of gas as a domestic fuel is one of the objectives of the national energy policy. Hence, a strong adherence to the Liquefied Petroleum Gas Safety Code of Safety Practice will reduce the risk associated with the domestic utilization of gas.
vii. Electrical Safety Code: Part 1 of the Institute of Petroleum (now Energy Institute) Model Code of Safe Practice
This Code is aimed at providing an overview of the particular issues related to the safe use of electrical equipment in the petroleum industry, specifically in areas where there is a possibility of occurrence of a flammable atmosphere. Guidance is given on the selection of equipment together with installation, inspection and maintenance practices. This Code is applicable to both onshore and offshore areas. It specifically excludes mines, areas where explosives are manufactured, stored or handled and areas subject to dusts.
Because natural gas is highly flammable, care should be taken, according to this standard in the use of electrical equipment to avoid ignition and explosion. In an area where a gas processing plant is situated near population as in Ebocha, following the dictates of this standard is critical for the gas companies.
viii. American National Standard Institute (ANSI) B31-3-Pressure Piping of Chemical Plant and Petroleum Refining Piping.
The ASME B31.1 / B31.3 Power and Process Piping Package prescribes the requirements for components, design, fabrication, assembly, erection, examination, inspection and testing of process and power piping. It includes ANSI/ASME B31.1-2012 and ASME B31.3-2010. The American Society of Mechanical Engineers (ASME) established the B31 Pressure Piping Code Committees to promote safety in pressure piping design and construction through published engineering criteria. Numerous sections of the B31 Codes provide the necessary guidelines to analyze new or nontraditional products so that sound engineering judgments can be made regarding Code conformance.
ix. American Society of Mechanical Engineers (ASME) – Boiler Pressure Vessel Code (Section 1)
The ASME Boiler and Pressure Vessel Code (BPVC) is an American Society of Mechanical Engineers (ASME) standard that provides rules for the design, fabrication, and inspection of boilers and pressure vessels. A pressure component designed and fabricated in accordance with this standard will have a long, useful service life, and one that ensures the protection of human life and property. Volunteers, who are nominated to its committees based on their technical expertise and on their ability to contribute to the writing, revising, interpreting, and administering of the document, write the BPVC.
x. API 550 Manuals of Refinery Instruments and Control Systems
This section discusses recommended practices for the installation of central hydraulic pressure systems that power hydraulic cylinders (actuators) to move valves, dampers, and similar types of equipment.
Successful instrumentation depends upon a workable arrangement which incorporates the simplest systems and devices that will satisfy specified requirements. Sufficient schedules, drawings, sketches, and other data should be provided to enable the constructor install the equipment in the desired manner. The various industry codes and standards, and laws and rulings of regulating bodies should be followed where applicable. For maximum plant personnel safety, it is recommended that transmission systems be employed to eliminate the piping of hydrocarbons, acids, and other hazardous or noxious materials to instruments in control rooms.