Connect with us

Features

Sri Lanka’s gas tragedy: the untold story

Published

on

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.)



Continue Reading
Click to comment

Leave a Reply

Your email address will not be published. Required fields are marked *

Features

UK support for govt.’s pragmatic reconciliation process

Published

on

Lord Ahmad with GL

By Jehan Perera

The government would be relieved by the non-critical assessment by visiting UK Minister for South Asia, United Nations and the Commonwealth, Lord Tariq Ahmad of his visit to Sri Lanka. He has commended the progress Sri Lanka had made in human rights and in other areas as well, such as environmental protection. He has pledged UK support to the country. According to the President’s Media Division “Lord Tariq Ahmad further stated that Sri Lanka will be able to resolve all issues pertaining to human rights by moving forward with a pragmatic approach.” The Minister, who had visited the north and east of the country and met with war-affected persons tweeted that he “emphasised the need for GoSL to make progress on human rights, reconciliation, and justice and accountability.”

Prior to the Minister’s visit, President Gotabaya Rajapaksa had announced in Parliament that his government had not violated nor would support “any form of human rights violations.” This was clearly an aspirational statement as the evidence on the ground belies the words. Significantly he also added that “We reject racism. The present government wants to safeguard the dignity and rights of every citizen in this country in a uniform manner. Therefore I urge those politicians who continue to incite people against each other for narrow political gains to stop doing so.” This would be welcome given the past history especially at election time.

The timing of Lord Ahmad’s visit and the statements made regarding human rights suggest that the forthcoming session of the UN Human Rights Council in Geneva, commencing on February 28, loomed large in the background. The UN High Commissioner for Human Rights will be presenting a written report on that occasion. A plethora of issues will up for review, including progress on accountability for crimes, missing persons, bringing the Prevention of Terrorism Act in line with international standards, protecting civil society space and treating all people and religions without discrimination.

The UK government has consistently taken a strong position on human rights issues especially in relation to the ethnic conflict and the war which led to large scale human rights violations. The UK has a large Tamil Diaspora who are active in lobbying politicians in that country. As a result some of the UK parliamentarians have taken very critical positions on Sri Lanka. Lord Ahmad’s approach, however, appears to be more on the lines of supporting the government to do the needful with regard to human rights, rather than to condemn it. This would be gratifying to the architects of the government’s international relations and reconciliation process, led by Foreign Minister Prof G L Peiris.

REACHING OUT

In the coming week the government will be launching a series of events in the North of the country with a plethora of institutions that broadly correspond to the plethora of issues that the UNHRC resolution has identified. War victims and those adversely affected by the post war conditions in the North and livelihood issues that arise from the under-developed conditions in those areas will be provided with an opportunity to access government services through on-the-spot services through mobile clinics. The programme coordinated by the Ministry of Justice called “Adhikaranabhimani” is meant to provide “ameliorated access to justice for people of the Northern Province.”

Beginning with Kilinochchi and Jaffna there will be two-day mobile clinics in which the participating government institutions will be the Legal Aid Commission, Office for National Unity and Reconciliation, Office for Reparations, Office on Missing Persons, Department of Debt Conciliation Board and the Vocational Training Authority to mention some of them. Whether it is by revising 60 laws simultaneously and setting up participatory committees of lawyers and state officials or in now launching the “Adhikaranabhimani” Justice Minister Ali Sabry has shown skill at large scale mobilisation that needs to be sustained. It is to be hoped that rather than treating them as passive recipients, the governmental service providers will make efforts to fulfill their need for justice, which means that the needs of victims and their expectations are heard and acknowledged.

It will also be important for the government to ensure that these activities continue in the longer term. They need to take place not only before the Geneva sessions in March but also continue after them. The conducting of two-day mobile clinics, although it will send a message of responsiveness, will only be able to reach a few of the needy population. The need is for infusing an ethic of responsiveness into the entirety of the government’s administrative machinery in dealing with those problems that reaches all levels, encompassing villages, divisions, districts and provinces, not to mention the heart of government at the central level.

The government’s activities now planned at the local level will draw on civil society and NGO participation which is already happening. Government officials are permitting their subordinate officials to participate in inter-ethnic and inter religious initiatives. It is in their interest to do so as they would not wish to have inter-community conflicts escalate in their areas which, in the past, have led to destruction of property and life. They also have an interest in strengthening their own capacities to understand the underlying issues and developing the capacity to handle tensions that may arise through non-coercive methods.

BUILDING PEACE

Many of the institutions that the government has on display and which are going to the North to provide mobile services were established during the period of the previous government. However, they were not operationalized in the manner envisaged due to political opposition. Given the potency of nationalism in the country, especially where it concerns the ethnic conflict, it will be necessary for the government to seek to develop a wide consensus on the reconciliation process. The new constitution that is being developed may deal with these issues and heed the aspirations of the minorities, but till that time the provincial council system needs to be reactivated through elections.

Sooner rather than later, the government needs to deal with the core issue of inter-ethnic power sharing. The war arose because Sinhalese politicians and administrators took decisions that led to disadvantaging of minorities on the ground. There will be no getting away from the need to reestablish the elected provincial council system in which the elected representatives of the people in each province are provided with the necessary powers to take decisions regarding the province. In particular, the provincial administrations of the Northern and Eastern provinces, where the ethnic and religious minorities form provincial majorities, need to be reflective of those populations.

At the present time, the elected provincial councils are not operational and so the provincial administration is headed by central appointees who are less likely to be representative of the sentiments and priorities of the people of those provinces. In the east for instance, when Sinhalese encroach on state land the authorities show a blind eye, but when Tamils or Muslims do it they are arrested or evicted from the land. This has caused a lot of bitterness in the east, which appears to have evaded the attention of the visiting UK minister as he made no mention of such causes for concern in his public utterances. His emphasis on pragmatism may stem from the observation that words need to be converted to deeds.

A video put out by the UK Foreign, Commonwealth and Development Office confirms a positive approach with regard to engaging with the Sri Lankan government. In it Lord Ahmad says “the last three days illustrated to me that we can come together and we can build a constructive relationship beyond what are today with Sri Lanka. We can discuss the issues of difference and challenge in a candid but constructive fashion.” Lord Ahmad’s aspiration for UK-Sri Lankan relations needs to be replicated nationally in government-opposition relations, including the minority parties, which is the missing dimension at the present time.

Continue Reading

Features

Yohani…teaming up with Rajiv and The Clan

Published

on

I know many of you, on reading this headline, would say ‘What?’

Relax. Yohani, of ‘Manike Mage Hithe’ fame, is very much a part of the group Lunu.

But…in February, she will be doing things, differently, and that is where Rajiv and the Clan come into the scene.

Rajiv and his band will be embarking on a foreign assignment that will take them to Dubai and Oman, and Yohani, as well as Falan, will be a part of the setup – as guest artistes.

The Dubai scene is not new to Yohani – she has performed twice before, in that part of the world, with her band Lunu – but this would be her first trip, to Oman, as a performer.

However, it will be the very first time that Yohani will be doing her thing with Rajiv and The Clan – live on stage.

In the not too distant past, Rajiv worked on a track for Yohani that also became a big hit. Remember ‘Haal Massa?’

“She has never been a part of our scene, performing as a guest artiste, so we are all looking forward to doing, it in a special way, during our three-gig, two-country tour,” says Rajiv.

Their first stop will be Dubai, on February 5th, for a private party, open-air gig, followed by another two open-air, private party gigs, in Oman – on February 10th and 11th.

Another attraction, I’m told, will be Satheeshan, the original rapper of ‘Manike Mage Hithe.’

He will also be a part of this tour (his first overseas outing) and that certainly would create a lot of excitement, and add that extra sparkle, especially when he comes into the scene for ‘Manike Mage Hithe.’

Yohani and her band, Lunu, last performed in Dubai, a couple of months back, and Satheeshan, they say, was the missing link when she did her mega internet hit song – live, on stage.

There was a crowd to catch her in action but it wasn’t a mind-blowing experience – according to reports coming our way.

A live performance, on stage, is a totally different setup to what one sees on social media, YouTube, etc.

I guess music lovers, here, would also welcome a truly live performance by Yohani de Silva.

In the meanwhile, I’m also told that Rajiv Sebastian plans to release some songs of the late Desmond de Silva which he and Desmond have worked on, over the years.

According to Rajiv, at this point in time, there is material for four albums!

He also mentioned that he and his band have quite a few interesting overseas assignments, lined up, over the next few months, but they have got to keep their fingers crossed…hoping that the Omicron virus wouldn’t spike further.

Continue Reading

Features

Multi-talented, indeed…

Published

on

Thamesha Herath (back row – centre) and her disciples (students)

We all know Trishelle as the female vocalist of Sohan & The X-Periments, so, obviously it came to me as a surprise when it was mentioned that she is a highly qualified Bharatanatyam dancer, as well.

What’s more, she has been learning the skills of Bharatanatyam, since her kid days!

And, to prove that she is no novice, where this highly technical dance form is concerned, Trishelle, and the disciples (students) of State Dance Award winning Bhartanatyam Guru, Nritya Visharad Bhashini, Thamesha Herath, will be seen in action, on January 29th, at 4.00 pm, at the Ave Maria Auditorium, Negombo.

Said to be the biggest event in Bharatanatyam, this Arangethram Kalaeli concert will bring into the spotlight Avindu, Sithija, Mishaami, Nakshani, Venushi, Veenadi, Amanda, Sakuni, Kawisha, Tishaani, Thrishala (Trishelle), Sarithya, Hewani, Senuri, Deanne and Wasana.

In addition to her singing, and dancing skills, Trishelle has two other qualifications – Bachelor in Biomedical Science, and Master in Counselling Psychology.

Continue Reading

Trending