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Sri Lanka’s gas tragedy: the untold story

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By Deshai Botheju, Ph.D.
M.Sc.Tech.(Norway), M.Sc., B.Sc.Eng. (1st Hons., UoM), AIChE, AMIE(SL)
deshaibotheju@acses.org

Recent explosions and gas leak accidents related to domestic LP gas cylinders have created an environment of fear, anxiety, and social unrest throughout the country. More than 400 explosions and gas leak incidents have been reported during the first week of December 2021. In addition, a large number of observations have been made with respect to leaking gas cylinder valves.

The reported accidents and incidents can be divided into four major categories: (a) Sudden gas explosions inside houses and building, (b) Sudden explosions associated with the gas cooker, (c) Major gas leaks and resulting damages associated with the regulator and the hoses, (d) Minor gas leaks from the cylinder valve, regulator, or the hoses. The number of accidents reported during a single week has far exceeded the typical gas-related accidents happening within a typical year. Something must have gone terribly wrong for Sri Lankan LP gas consumers. Unconfirmed reports now indicate potential deaths, associated with some of these gas explosion accidents.

What is LPG?

Liquefied Petroleum Gas, abbreviated LPG, is an energy carrier derived during crude oil refining or natural gas processing. In petroleum industry terminology these are called gas condensates and are byproducts often generated during the production of liquid fuels (gasoline, diesel, and kerosene) or natural gas (methane). The key components of typical LP gas are propane (an alkane gas containing three carbon atoms – C3H8) and butane (an alkane gas containing four carbon atoms – C4H10). In addition, small amounts of propylene, methane, pentane and other minor constituents can be present. LP gases do not originally have a clearly recognizable distinct odour. Therefore, in order to identify any gas leaks, methyl mercaptan (CH3SH), or a similar odour generating component, is added to LP gas before commercial use. Table 1 provides a useful comparison between propane and butane, with respect to key physical or chemical properties.

Depending on the refinery process, or intended use, LP gas can have a widely varying propane and butane composition. Under normal atmospheric pressure, butane has a higher boiling point of minus 0.5 degrees Celsius (-0.5) compared to propane’s minus 42 degrees Celsius (-42) boiling point. That means in colder climates, where the ambient temperature could go below 0 degrees Celsius, the LP gas must mostly contain propane in order to use that as a fuel gas (otherwise it wouldn’t flow as a gas, as butane would remain in the cylinder as a liquid). Therefore, the butane content is greatly reduced in LP gas used in colder climate countries, typically less than five percent of the volume. For tropical countries, like Sri Lanka, having a high butane content is just fine, as the year-round temperature is almost always above zero degrees Celsius (except for some rare occasions in locations at higher altitudes). Further, butane is a much safer gas to use. This is due to its much lower vapour pressure (31 pound per square inch) compared to that of propane (124.5 psi). Therefore, the containment integrity requirements shall be much stricter for propane use, compared to butane. (figure I)

Composition changes and pressure effects

Unlike compressed gas cylinders, LP gas cylinders are not filled with 100 percent gas. Instead, a new cylinder would contain the liquids, hence the name LP gas, to about 85 percent volume. Only the remaining 15 percent ullage volume (the volume left empty in a tank for the liquid to expand) contains actual gas. These two phases (liquid and gas) are in equilibrium. The pressure within this gas filled ullage is the equilibrium pressure of the corresponding liquid mixture (of propane and butane). This equilibrium pressure can be predicted based on the ambient temperature and the composition of the liquid phase. Table 2 provides the values of these equilibrium pressures (in pounds per square inch gauge or psig) for different propane-butane mixtures at the temperature of 32 degrees Celsius (which is quite close to the typical ambient temperature in Sri Lanka). (Figure II)

As can be seen from Table 2, at 32 oC temperature, a mixture of 80 percent butane and 20 percent propane has an equilibrium pressure of 53.6 psig. This was the composition used in Sri Lanka for a long time. All appliances (including gas cookers), pressure regulators, hoses, hose connectors, gas cylinder valves and cylinders have been accustomed to this pressure condition. In other words, our consumer gas utility system has been calibrated at this pressure condition. Nevertheless, gas cylinders themselves are manufactured to tolerate a much higher pressure.

If the butane-propane composition is suddenly changed to 50 % butane and 50 % propane, now the increased propane content leads to a much higher equilibrium pressure of 89.4 psig. It is obvious that this is a very significant pressure increase from the previous condition.

Containment integrity

Increased propane content leads to a significant increase in gas pressure inside the cylinder. This is because propane has a much higher equilibrium vapour pressure compared to butane (see Table 1). Now, the whole utility system on the part of the customers faces a containment integrity problem. In other words, gas leaks are likely to happen from many of the system components. Table 3 elaborates potential impacts of this pressure increase on different system components. Figure 1 further illustrates potential leak sources and pathways associated with the gas cylinder valve. (Figures III and IV)

What happens during a gas leak?

Propane and butane are flammable and combustible gases, when mixed with air (or oxygen). Within the approximate volume percentages of 2 to 10 percent (within LEL- Lower explosive limit and UEL – Upper explosive limit), these gases can create an explosive gas mixture when exposed to air; see Table 1. Outside of this volume percentage range, the gas would not ignite. However, at higher gas concentrations, the gas cloud can still pose an asphyxiation hazard to humans as it displaces breathable oxygen in air.

Even a minor gas leak in the cylinder valve, regulator, or any other component (see Table 3 and Figure 1) can lead to the accumulation of the gas inside a building, over several hours. Note that both propane and butane gases are higher in density compared to air (heavier than air; see specific gravity values shown in Table 1). Which means, when a gas leak occurs the explosive gas cloud accumulates close to ground level (rather than moving upward and dissipating). This situation is more likely to occur at night when doors and windows are closed, with consequently little or no ventilation. If the leaked cloud of gas reaches the concentration of LEL within that surrounding (for example a kitchen), then it is a bomb waiting to be triggered at any time. The only thing required is a small spark, which may occur when an electrical switch makes contact (on or off), or even due to static electricity present in the atmosphere, or due to an actual flame such as lighting a match. At that moment, an explosive combustion reaction occurs within the flammable gas cloud and the energy released is transmitted as a pressure wave accompanied often by a fireball. This is a typical atmospheric gas cloud explosion. Secondary damage can occur due to projectiles (broken glass for example), prolonged fires, collapsing roofs and walls.

Change management failure

Changing an existing LP gas composition without a detailed safety assessment is an act of sheer negligence bordering on absurdity. It’s a fundamental process engineering principle to follow a comprehensive Management of Change (MoC) protocol before making this kind of, or even far less consequential, change to a product, process, or an operating procedure. Even a Process Engineering Trainee can explain this to production management. As part of an MoC process, it is absolutely necessary to conduct a dedicated risk assessment or a standard safety study such as ‘HAZards and Operability’ (HAZOP). Had such HAZOP been conducted in this case, many of the problems we have indicated in Table 3 could have been identified in advance, avoiding calamity in consequence.

Cost factor and energy contents

The heat energy contents of propane and butane are respectively 49.58 and 47.39 megajoules per kilogram (MJ/kg). However, the density of liquid propane and butane are 0.51 and 0.58 kilograms per litre (kg/L) respectively. That means due to the lower density of propane compared to butane, propane has a slightly lower energy content when based on volume (25.3 and 27.5 MJ/L respectively). Propane burns with a slightly higher flame temperature compared to butane (1980 vs 1970 oC). In certain gas burners, propane could burn with slightly higher efficiency compared to butane (with less deposition of carbon).

If calculated based on the heat energy content delivered (measured by BTU-British Thermal Units), propane is often a cheaper energy commodity compared to butane in the world energy market. Therefore, an LP gas mixture rich in propane can be cheaper. LP gases with more propane are also easier to procure. While per BTU price is cheaper, if calculated based on metric ton price, one can be misled to believe that propane is more expensive than butane. This becomes a false assumption if all gas pricing and market economics are based on the value of BTUs (energy) delivered to the customer (customer is made to pay for the heat energy content delivered to them, and not for the weight of the gas). Also note that the exact price of a certain LPG shipment can be very different from the typical spot prices prevailing in the world energy market.

Safety culture issue

Every organisation has a certain safety culture. Without going into detailed academic definitions of the safety culture concept, we can still try to understand different characteristics of good (positive) safety cultures in comparison to bad (negative) safety cultures.

In a good safety culture Management of Change protocols are always followed; when an accident or an incident occurs, it will always be investigated to the fullest extent and all lessons to be earned are extracted; transparency and honesty are always maintained; instead of finger pointing, their own faults are admitted; no attempts are made at concealing information; safety is always given priority over marginal economic gains. In contrast, the complete opposite of these is to be expected of an organisation with a negative safety culture.

Investigation and compensation

Any investigation into the recent series of unfortunate gas related accidents in Sri Lanka must not stop at merely identifying plausible physical causes. Such investigation must definitely look deeper into related organisational factors, and make necessary recommendations to bring about much needed organisational reforms in the form of enhancing safety culture. In addition, more systematic safety management requirements and stricter regulatory reforms must be recommended to avoid repetition of this kind of ‘organizationally rooted accidents’. Failing to do so may lead to greater disasters of higher magnitude in future. Prompt compensation to those who faced harm must be a priority. Even more urgent is to recall every single gas cylinder delivered with hazardous pressure conditions, irrespective of whether the gas has been used or not. As explained before, LP gas cylinders will retain the same high pressure condition until the last drop of liquid is vaporised. Therefore, unused as well as almost fully used gas cylinders will pose the same level of leaking hazard.

(Facts presented in this article are based on information available on the public domain. The analyses and opinions are based on the author’s experience in the industry, and do not reflect the opinions of any institution.)



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Features

‘Lord Edgware Dies’

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It has been some time since I read an Agatha Christie, the plot of which I cannot remember. So, I was delighted to find on the shelves of a friend Lord Edgware Dies, which I had a vague memory of, but no certainty about who had done it.

When I read it, I found that my memory of who was probably the killer was correct, but I could not be certain and the red herrings Christie threw in were so diverting that until almost the very end I wondered if I had been wrong.

The plot is very simple. Jane Wilkinson, who is married to Lord Edgware, tells him that she is desperate for a divorce since she is in love with a very proper Anglo-Catholic peer, Lord Melton, but Edgware refuses to divorce her. She asks Poirot to talk to him, which he does, and is surprised to find that Edgware has told Jane he is prepared to give her a divorce. This was, after he had categorically refused, through a letter, which Jane said she had not received.

That night Edgware is murdered, after Jane had been to see him, or so the butler said, and also Edgware’s secretary. But Jane had been that evening at a grand dinner many miles away, where a dozen fellow guests could swear to her presence.

There was a solution however to the mystery of two Jane Wilkinsons, namely a skilful impersonator called Carlotta Adams who, in the opening chapter had impersonated Jane Wilkinson, who had also been at the performance. But when Poirot goes to see her, he finds that she had been found dead on the morning after Edgware had been killed, of an overdose. And in her bag was a gold case, with a strange inscription, that contained the drug, along with a pair of pince-nez.

Her maid said she had written a letter to her sister in America and posted it the previous night. Poirot asks Inspector Japp to get the letter, and a transcript is received from America, and in it the name of Edgware’s nephew Ronald Marsh is mentioned; he had taken Carlotta to dinner after her performance, with which the book opens, and had then set her a challenge. Japp arrests Marsh, but Poirot is not happy and asks for the original of the letter, which the sister sends him. That shows that a page is missing, and the tear is obvious, though that raises the question as to why it had not simply been cut.

Matters are further complicated by the fact that Marsh had gone in a taxi to the Edgware house, along with Edgware’s daughter Geraldine, in the interval of an opera which had previously seemed to provide them with cast iron alibis. Geraldine had gone in to fetch her pearls so that Marsh could raise money he needed, and thus had an opportunity to kill Edgware, as did Marsh, for the driver said he had got out of the taxi while waiting and gone into the house.

Agatha Christie

Marsh explained why he had gone to the house on the night of the murder as having followed Bryan Martin, an American actor, who had been in love with Jane, whom he saw go into the house with a key. But there was no one visible when he entered, and Geraldine almost immediately came down and they left together. And Martin too has become an object of suspicion to Poirot, for he had been to see him before the murders were discovered with a story of being followed by a man with a gold tooth – a story Poirot immediately realized was false when he was asked how old the man was, and was told he was young, for young people did not have gold teeth.

A heap of French money Edgware had got for a trip to Paris was missing, but since Marsh had no need for it after his cousin’s offer of help, Poirot deduces that it must have been taken by the butler, who has disappeared. Christie has stressed that he is astonishingly handsome, unusual in a butler, and Poirot notes a resemblance to Martin, so he thinks the mysterious man going into the house must have been him.

Incidentally, later Poirot assumes that Edgware’s change of mind was because he was involved in some scandal, and I believe Christie intends us to see the cause of this in his handsome butler, though this is not specified.

Meanwhile, Poirot has asked Japp to find out the provenance of the case found in Carlotta’s handbag, and it turns out to have been made in Paris, specially commissioned, and collected by a woman with pince-nez.

But then another murder occurs—that of another guest at the grand dinner, which provided Jane with her alibi. The victim is an actor who had been bemused when Jane, at a lunch, thought the Judgment of Paris referred to the city. He told Hastings he wanted to see Poirot, but was killed before he could get to the appointment. Poirot had rushed there when told about his request, but it was too late.

Meanwhile, Poirot has tried out the pince-nez on Edgware’s secretary, but she could not see through these. It was only a chance remark heard outside the theatre that led him to try them out on Wilkinson’s maid Ellis, a spare pair that had been appropriated for the night of the murders.

Poirot then lays things out, having summoned Martin and told him that he probably suppressed Edgware’s letter, as he had been dropped by then and he did not want Jane to marry another. But after teasing Martin, Poirot says that Jane was in fact the murderer, and she got Carlotta to impersonate her at the dinner while she went to the house and killed her husband. After meeting Carlotta later and checking with her through a call that she had not been rumbled, Jane had gone ahead with the murder – she put veronal into her drink and the case with veronal into the handbag. She forgot to take out the pince-nez she had used earlier to imitate an American. Carlotta had registered as the American in a hotel and Jane had gone to see her, and there they exchanged identities. After seen the letter, she made use of it by tearing off the page that referred to her, and the S of She, so that the person who had challenged Carlotta to impersonate her seemed to be a man.

There is a coda in which Jane, condemned to death, writes to Hastings, still full of pride at her ingenuity hoping she will be remembered.

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Desilt reservoirs, learn from our ancient irrigation systems

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Polgolla

by Prof. O. A. Ileperuma

Silting of reservoirs is a major problem today affecting our hydropower production and irrigation systems. The main Mahaweli reservoirs are silted to a considerable extent reducing the water holding capacity of them. Due to poor soil management practices, floodwaters deposit large amounts of silt in these reservoirs. When the Polgolla reservoir was fully drained about two years back, one could see mountains of silt in the lower reaches of the reservoir. A rough estimate is that 50% of the total capacity of these reservoirs has been lost to siltation. This is a serious issue which affects not only power and agriculture but also flood control.

Our ancient irrigation systems ensured that desilting of reservoirs took place under royal decree where all users of the reservoirs were ordered to carry out desilting of reservoirs during the dry season. The clay thus collected was used in making bricks for the construction of great stupas which dot the landscape of our ancient kingdoms. This ensured that the reservoirs had their full capacity filled with water for the next cultivating season. Our ancient kings were clever enough not to construct reservoirs by blocking main rivers such as the Mahaweli. A classic example is the Minipe left canal where they tapped only the surface water of Mahaweli. Even the bigger tanks such as Nuwara Wewa and Parakrama Samudraya were fed with minor rivulets. There were also other ingenious features in the cascade irrigation systems built by the ancient kings, such as mud sluice canals and forest reservations between the reservoirs in the cascade system. These reservations helped trap silt and remove excess nutrients, which could otherwise contribute to increasing salinity as water flowed from one reservoir to another.

Victoria

Moragahakanda

A classic engineering marvel is the former Yoda Ela, which carries water from Kalawewa to Nuwara Wewa and Tissa Wewa. It is 87 km long although the straight distance between these points is only about 40 km. The gradient of this canal is about 10 cm per km or 6 inches per mile. Yodha Ela functions as a moving reservoir and feeds about 4,600 hectares of paddy lands. It is a winding canal with about 120 smaller reservoirs on its way. It was constructed during the reign of King Dhatusena around 459 AD and later expanded by King Parakramabahu by connecting more reservoirs to the network. Unfortunately, during the Mahaweli project our modern-day engineers constructed a concrete canal replacing the winding path of this Yoda Ela also called Jaya Ganga. This effectively removed the ability of the old Yoda Ela to remove silt and nutrients. The bank of this Ela has wet zone trees such as jak and areca nut growing well. They take up the nutrients from the flowing stream making the water suitable for irrigation later.

Ancient Mesopotamian civilisations depended on dams constructed along the two main rivers, Euphrates and Tigris. After continuous irrigation of their fields over several thousand years, salinity of the irrigated lands increased making them unsuitable for agriculture. People died due to famine and this clearly illustrates the danger of blocking main rivers for agriculture. There is scientific evidence that the salinity of paddy soils in the Mahaweli C area is increasing.

We saw the devastation caused by Cyclone Ditwah. The sluice gates of the Kotmale Reservoir were opened, and Kandy and Peradeniya were flooded. If the reservoir had had greater storage capacity, couldn’t the opening of the gates have been delayed? This may not be an argument that modern-day engineers would readily accept, and I am not an irrigation expert. These ideas may well be naïve. But most of us tend to think of reservoirs mainly in terms of hydropower generation and irrigation, while their role in flood control receives much less attention. The question therefore deserves serious consideration. Could restoring lost reservoir capacity through desilting help improve our ability to manage extreme rainfall and reduce flood risks?

Desilting our reservoirs should be considered a national priority.

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Losing out to Ethiopia

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From Trailblazer to Tailender

Export diversification – Missing the wood for the trees – Part III

by Gomi Senadhira

In Sri Lanka, the word “Ethiopia” is often used as disparaging slang to describe individuals or areas experiencing extreme poverty, starvation, or severe economic hardship. This linguistic habit originated in the 1980s with the Western media coverage of the devastating Ethiopian famine of 1983-85. That media coverage shocked the world but also left an outdated and offensive global stereotype that the country is permanently starving. Much has changed since then. By now, with an annual growth rate of around 9%, it is the fastest-growing economy in sub-Saharan Africa. Ethiopia has also emerged as a highly competitive exporter and is challenging not only its competitors in the region but also countries like Sri Lanka. This article is on how Sri Lanka has lost ground to Ethiopia (and a few other countries) in the GCC markets for agricultural and floricultural products.

Sri Lanka – A Pioneer in the Agriculture and Floricultural Market in the GCC

As discussed in Part II of this article, by the mid-1980s Sri Lanka had established a strong foothold in the GCC’s fruit, vegetable, and floricultural market. Geographical proximity and well-established shipping and air links gave Sri Lanka a strong comparative advantage over Southeast Asian and African nations. Thailand, Vietnam, and Kenya were not even in the market. At that time, Ethiopia was experiencing (as BBC news reports described) “a biblical famine”.

The market was not very large, but it was lucrative and growing. Trade Minister Lalith Athulathmudali as well as the Chairman of the Export Development Board, Victor Santiapillai, who visited Kuwait (and the GCC countries), recognised the market potential for these products and encouraged us to continue with our work. The minister was particularly keen to further develop links between the market for these products, exporters, and his Export Production Villages (EPVs). So, it was becoming a successful case not only for export diversification but also for transferring gains from exports directly to rural households.

From Trailblazer to Tailender

As a result, even by the beginning of this century Sri Lanka had a larger market share than most of its competitors from Asia or Africa. But since then, our competitiveness has weakened significantly. The tables below provide a comparative snapshot of Sri Lanka’s performance vis-à-vis Thailand, Vietnam, Kenya and Ethiopia in the GCC market for vegetables, fruits and floricultural products. As illustrated therein, in 2001 Sri Lanka was ahead of Thailand, Kenya and Ethiopia in this small but rapidly growing market. Since then, we have fallen behind Thailand, Kenya and many other countries in that lucrative market. If this trend continues, Sri Lanka will fall behind Ethiopia within the next few years. (See Table 1)

In the GCC market for vegetables (covered in HS chapter 07), Sri Lanka was ahead of most other competitors in 2001. As illustrated in Table 1 , Sri Lanka had failed to develop this market, while Thailand, Kenya, and even Ethiopia had very efficiently increased their market shares. The GCC is a market to which Sri Lanka can supply some vegetables, like cabbages, by sea. It appears Sri Lanka had also failed to exploit this mode of supply.

We can see a similar trend in the market for fruits. Vietnam, Kenya, and Thailand have emerged as major players, while exports from Sri Lanka have staggered on slowly. In this segment, Vietnam has emerged as a leading player during the last twenty years and the GCC imports from Viet Nam have shot up from US$44 thousand in 2001 to US$346 million by 2024. In part one of these articles, I discussed the remarkable increase of jackfruit exports from Vietnam “…just $3 million in 2015 to an impressive $236.8 million in 2023” while most of our jackfruit production rots under the trees. This explains how countries develop their markets, geographically and product-wise. (See Table 2)

Sri Lanka’s performance has been weakest in the market for floricultural products (HS Chapter 06), which groups live trees, cut flowers, and ornamental foliage. When we first entered the market in the 1980s, the market was dominated by the Netherlands, and Kenya and Ethiopia were not even in the market. At that time, we identified the Gulf states as a market where Sri Lanka could have a dominant presence due to geographical proximity. Even in 2001, Sri Lanka was ahead of Kenya, Ethiopia, and Thailand. But by now, Kenya has emerged as the dominant supplier. Ethiopia is also expanding its market share and is the third-largest exporter. (See Table 3)

Missing the Wood for the Trees

In the mid-1980s, Sri Lanka first established its foothold in the GCC market. Since then, Thailand, Vietnam, Kenya, and even Ethiopia have moved well ahead of us and have become leading players. Why did we lag behind in our export diversification efforts in general and, more particularly, in the GCC market?

The reasons are very clear. After the initial attempts in the 1980s and early 1990s, Sri Lanka has not been proactively involved in identifying, developing, and promoting new products and markets, or protecting and further developing new markets already established. The focus has simply been on traditional exports: tea, coconut, cinnamon, and garments, while other products were almost ignored. In essence, we have been and continue to focus intensely on a narrow group of products and markets, and we have lost sight of the bigger picture.

(The writer can be reached at senadhiragomi@gmail.com)

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