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More yellow stuff, where do we put it?

Increasing flexibility for disposing of excess sulphur. Mega projects, mostly in the Middle East region, have dominated discussions involving sulphur recently. This is for good reason, considering the size and number of SRU trains and their associated elemental sulphur production are unprecedented.

Eric Harbaugh
Enersul LP
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Article Summary
Massive sulphur recovery trains producing thousands of tons of sulphur per day are certain to change the dynamics of the sulphur market, and they are certainly fascinating engineering projects as well. However, there are dynamics in the market, some related to these projects and some not, which are having a meaningful impact on oil and gas processors and their consideration of sulphur.

First, there is the expected impact on the global sulphur market of the new supply of large volumes of sulphur. In the GCC alone, current projects are projected to result in a sulphur supply increase of more than 5.5 million metric tons per year in the next 2 years. With so much production from only one region, some marketers are anticipating larger price differentials in different parts of the world. This means that some sulphur consumers who have traditionally purchased from specific regions based on freight costs may desire to expand their sources of supply. For example, several North American phosphate fertilizer producers who have traditionally sourced their sulphur primarily or even entirely from the North American molten market are now considering adding the capability to import solid sulphur from the global market. The secondary effect of this is that many North American refiners and gas processors, especially smaller producers without significant sulphur market clout may find their long-standing sulphur customers may no longer be interested in their sulphur.  This is but one example of how increased production in one part of the world can have a meaningful impact in what have traditionally been isolated markets. Similar effects of altered trade flows can be expected in other parts of the world.

Secondly, beyond the large increases of sulphur supply at the mega-producers, there are increases in sulphur production on the small end of the spectrum as well. This is due to both changes in feedstock sulphur content as well as ever-tightening standards of allowable sulphur content in fuels. Although the ongoing increases in oil and gas production from shale formations are generally sweet, production from more sour sources, particularly Canadian oil sands and Venezuelan heavy crude continues to increase. Not only that, but governments around the world are steadily decreasing the quantity of sulphur they allow in end products. Changing allowable sulphur content in gasoline from 25ppm to 10ppm or even from 100ppm to 10ppm will not increase sulphur production at a refinery by thousands of tons per day. However, it can have a meaningful impact, especially for those producers who rely on truck transportation of molten sulphur to nearby sulphur consumers to dispose of their sulphur. Molten sulphur trucks normally do not include their own heating medium, confining their range to the distance the molten sulphur can reliably be transported without solidifying. If the one sulphuric acid plant down the road that takes all of a refinery’s sulphur production doesn’t need an additional one or two truckloads of sulphur per day, where will that extra truckload go?

When the combined effects of large increases of production in some corners of market and small, incremental increases in other corners are considered together, it becomes clear that the fairly balanced market that has existed for the past few years may shift in a meaningful way. As a result, forward thinking sulphur producers are preparing alternatives means of moving their sulphur. Some of the things being employed by various producers around the world include adding sulphur forming when they have always moved only molten sulphur, gaining access to a blocking facility, and developing alternative markets.

First, many producers around the world, especially smaller producers and those in markets like North America and Western Europe where there is significant transportation infrastructure for moving molten sulphur, only possess the capability to store and load-out molten sulphur. They have never needed to form their sulphur.  However, some are realising that the ability to solidify their sulphur into a high quality formed shape provides flexibility that serves as insurance against an unpredictable market. First of all, formed sulphur gives the producer access to markets outside the molten market in their region. This opens them up to literally thousands of customers around the world. Most solid sulphur is moved by bulk cargo ship, but there are many customers who can take sulphur in 50kg bags, 1000kg bags, or even loaded directly into containers. The other benefit of forming the sulphur into a solid product is that it increases the range of options of moving and storing sulphur. Molten sulphur must be kept in a tank or sump, and it must be kept hot. Once the sulphur is solid in a high quality form, it can be handled like any other bulk product. It can be put into bags, poured on a pad or in a warehouse, and moved in virtually any truck designed to handle solids.

What kind of equipment is required in order to form sulphur? The forming unit is the core piece of equipment required. There are two types of equipment commonly selected by smaller producers. The first is the pastillation unit. This piece of equipment consists of a stainless steel conveyor belt with a spray of cooling water applied to the bottom of the belt. Droplets of molten sulphur are deposited on the belt, which cool into flat-bottomed pastilles as they travel along the length of the belt. They are scraped off the belt at the discharge end and drop into a conveyor for further handling. The unit is normally located inside a building along with the other ancillary equipment required to keep the unit running. The most common unit using this technology produces 100-120 tons per day of product, although pastillation units are offered in capacity up to about 350 tons per day.

The second piece of equipment available for smaller producers is the Enersul mini-WetPrill. This unit was developed specifically with the existing sulphur producer in mind. It has a very small footprint and does not require a separate shelter except in extremely cold climates. It is a completely self-contained unit which requires only utilities and molten sulphur connection to the skid which measures only about 7’ wide by 15’ long. This makes it easier to fit into an existing facility and quick to install. It also does not have any specialised components requiring unique operations or maintenance skills in order to operate and maintain. The standard capacity of a mini-WetPrill is 100 tons per day. In addition, it is designed to be able to deposit product into a conveyor or directly into 1-ton “supersacks,” eliminating the need for any other equipment. Regardless of the technology chosen, formed sulphur opens up new markets and new storage and transport options which do not exist when handling molten sulphur.

The next action being taken by producers in preparation for possible market changes is to gain access to a blocking facility. For new facilities or those in the enviable position of having excess real estate, they can build the facility at the refinery or gas plant. A traditional pouring tower or the Enersul ProPivot pouring tower is installed in order to be able to pour large volumes to block for medium to long-term storage. Although blocked sulphur is more difficult to bring to market, in the case of an extended disruption in market access, it is an excellent way to store large volumes of sulphur. In addition to building a block at the site, some producers are moving to gain access to blocks at other sites. This can be another facility owned by the same company, or it can be a third party site. The two need to be connected by a reliable molten sulphur transportation network, but otherwise do not require close geographic proximity. This is chosen as a sort of insurance policy against market disruption. A site does not have to build anything or consume space on the site, but they commit to a maintenance fee or other reservation commitment to ensure there is capacity available for their sulphur if they need it. Blocking offers the advantage of being able to accept sulphur at a much higher rate than a small forming facility with a comparable capital investment.

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