Many companies appreciate the quality of services that are “engineered in Germany” – whether they are here in Europe or at the other end of the world. Just one example is BUCHEN’s Russian subsidiary, BUCHEN Industrial Services OOO, which is based in Ufa and has an excellent reputation for carrying out professional tank cleaning work, especially on large tanks. The company is well known for its reliable services, which are always delivered in line with the most stringent health, safety and environmental standards, no matter how complex the circumstances.
Different countries, different challenges: long distances to get to the customer, rough terrains, extreme weather conditions … The challenges faced by companies offering tank cleaning services to Russian refineries and oil terminals are completely different to those their counterparts must deal with here in Western Europe. No matter where in the world it may be, however, BUCHEN always cleans tanks using closed and automated systems which it has developed and adapted itself to ensure they are fit for purpose. Which is why these systems are also deployed in Russia to deliver safe and environmentally compatible tank cleaning services and recover high volumes of crude oil for re-use.
In March 2017, BUCHEN travelled to De-Kastri – a Russian town situated almost 11,500 kilometres from Cologne – to clean an 18m high storage tank (diameter: 95 metres, nominal capacity: 112,000 cubic metres). De-Kastri, a coastal town on the Sea of Japan, is located in the Khabarovsk region in the Russian Far East and home to an export terminal belonging to ‘Sakhalin -1’, one of the country’s largest oil and gas production projects. All of the oil produced there is handled by this terminal. With the two large tanks having been in use there since 2005, it was now time for the first of them to be emptied, cleared of 3,000 cubic metres of sludge and cleaned so inspection and welding work could be carried out – with project operator Exxon Neftegas Ltd’s strict safety standards being adhered to from start to finish.
In Atyrau (Kazakhstan), the BUCHEN specialists worked on a 32,500m³ crude oil tank with a domed roof
Projects involving climatic conditions similar to those in the Arctic and a location that even Russians would call remote need to be planned meticulously in advance – and this is precisely what BUCHEN’s specialists did together with their German colleagues to ensure that the cleaning work in De-Kastri went smoothly. Managing Director, Ljudmila Ochotnikova, commented: “Both our processes, methods and know-how and our employees’ specialist qualifications and training are just as important here in Russia as they are elsewhere in Europe. The supply network here, however, is totally different. This is a huge country and if a piece of machinery breaks down you can’t simply go around the next corner to find the spare part you need or get more staff. All possible contingencies must be planned for in advance.” Which is exactly what they did here in De-Kastri, too, taking along a spare unit for every piece of equipment they intended to use.
100 m
Diameter
112.000 m³
Capacity
The oil tank itself was cleaned using a closed and automated system. This tank-cleaning process is not only the safest way for operatives to carry out their work, it is also the most environmentally friendly. What’s more, it is able to recover high levels of crude oil from the sludge. This method involves a number of different stages: firstly, the jet washer system was installed and the paraffinic deposits on the floor of the tank sprayed with heated crude oil until the floating roof settled on its supports. Following this, nitrogen was used to create an inert atmosphere so that the deposits could be flushed out – first with crude oil and then with water. The next stage was to remove the waste air and gas via the access manholes in the side of the tank. Finally, vacuum trucks were brought in to extract any remaining deposits from the floor of the tank before the whole of the tank interior was cleaned with hot, high pressure water.
The cleaning specialists had to deploy a whole range of equipment to complete this work, all of which was loaded into sea containers in Ufa and then transported by truck to the terminal: everything needed for the project, which lasted several months, was delivered to the site – from jet washers (see illustration), to nitrogen generators, high pressure pumps, water traps, compressors and heat exchangers, all the way through to a workshop for repairing the operatives’ respirators.
A bespoke cutting unit, specially designed and built for this project, had also been transported to De-Kastri to enable the specialists to cut the liner tubes in the roof supports. The walls of these tubes were unusually thick (12 millimetres). Normally, the jet washer heads are slotted through these to get to the inside of the tank but this was not possible here as the tubes were too long for the lances. Working closely with the site’s operator, the BUCHEN experts drew up a strict timetable to remove the roof supports and shorten the tubes. Everything went just as planned and all work was completed according to schedule.
A bird’s eye view of the giant tanks
In Atyrau (Kazakhstan), the BUCHEN specialists worked on a 32,500m³ crude oil tank with a domed roof
A second team were also successfully cleaning another large tank in Atyrau, Kazakhstan, around the same time: here, though, the BUCHEN specialists were working on a 32,500 cubic metre crude oil tank with a domed roof. As was the case in De-Kastri, the tank (ca. 20m high and 48m wide) had to be emptied and cleaned so it could be inspected and overhauled. It was located in the Atyrau oil terminal, which stores and processes oil delivered by pipeline from the Karachaganak field 635 kilometres away.
Here, too, the tank was cleaned using a closed and automated system and crude oil to flush out the deposits. The main challenge that the company had to face in this particular project was the unusual dome-shaped floating roof as the BUCHEN experts had to develop a bespoke solution to enable them to install their cleaning equipment. The pressure pipelines, for example, had to be attached to the roof access ladder rather than along the tank’s inner and outer walls, which would have been the standard procedure. “Drawing up tailor-made solutions is, of course, one of our specialties,” explained project manager, Vadim Mansurov.
As in Germany, the operatives deployed for the project had to take part in special safety training courses and prove they were able to perform the work. Participating in seminars organised by the customer to learn about the on-site safety and emergency measures is a normal part of their work as is compiling project-specific method standards. This involves defining all individual work stages and all technology and equipment that will be needed for the project and then presenting these details to the client.
“Over the years, we have been able to demonstrate our professional approach and the high quality of our work in many different projects and locations and we are really pleased to be able to add De-Kastri and Atyrau to this list,” concluded Ljudmila Ochotnikova.
BUCHEN uses closed and automated systems to clean tanks, which it has refined itself to meet the particular requirements of the international market. Cleaning tanks by hand is particularly difficult work for the operatives and most of these complicated tasks can be avoided when automated systems are used. Customers benefit financially as high amounts of crude oil can be recovered from the sludge which, in turn, reduces the sludge disposal costs.
Jet washers are often used to clean large tanks. These are modular systems which can be installed in sea containers enabling them to be transported to wherever they are needed at short notice. The main components of this explosion-proof cleaning system are its mobile suction and pressure modules as well as its jet washers. To be able to clean the tank, a number of the tank roof supports are temporarily retracted so that the washers can be inserted through the liner tubes into the tank. The whole cleaning process is further facilitated by the special pipe system with its tried and tested, quick release stoppers and its high performance filters.
Once the system has been set up, the product is first removed from the tank using one of the suction modules and then run through a steam-powered heat exchanger where it is heated up to between 40°C and 60°C. The pressure module then pumps this warm product back into the tank via the jet washers so it can act as a cleaning media. With the nozzles rotating in three dimensions, the product enters the tank at high speed and is aimed at the solid and semi-solid contents in the tank so that they are dislodged and liquefied. The heat reduces the viscosity of the cleaning media, further facilitating this process. Inorganic residue such as sand and rust settle on the floor of the tank, while the organic components in the sludge are dissolved.
The empty space in the tank is made inert with nitrogen to prevent a build-up of static electricity during the individual cleaning phases. Moreover, the oxygen content is monitored throughout the whole process. If oxygen levels reach a certain point, the tank cleaning system automatically shuts itself off.