1. GENERAL DESCRIPTION OF COMPANY ACTIVITIES
- Metal Treatment Technology (S) PL undertakes chemical cleaning work and manufactures and sells a range of cleaning and maintenance products.
- In the field of chemical cleaning, Metal Treatment Technology (S) PL is active in the Singapore industrial sector, the Singapore marine sector, as well as internationally.
- Chemical cleaning work is done on-site at the clients’ premises, and in the Metal Treatment Technology (S) PL cleaning workshop in Singapore.
- Outside of Singapore, Metal Treatment Technology (S) PL has completed industrial projects in Indonesia, Brunei and Malaysia. Metal Treatment Technology (S) PL has completed marine projects in Singapore and China.
- In collaboration with other companies, Metal Treatment Technology (S) PL has assisted in the completion of completed both marine and industrial projects in Indonesia, the UAE, Saudi Arabia, The Netherlands, Italy, Egypt and Uruguay.
2. TYPES OF CHEMICAL CLEANING PERFORMED.
2.1 PRE-COMMISSIONAL CHEMICAL CLEANING
Applied to new constructions. The materials that make up the vast majority of chemical cleaning requirements are stainless steel of various grades and carbon steel. In both cases the object of the exercise is to remove contaminants derived from the construction process to ensure that these (a) Do not impede the function of the plant when in operation, while (b) Also ensuring that the useful lifetime of the material is maximized by minimizing its liability to corrode.
The method of chemical cleaning and the types of chemicals employed depend on the material and the equipment in question.
For example, stainless steel piping is to be cleaned, pickled and surface passivated. The piping will undergo several chemical and physical processes. Initially alkaline component/synthetic soaps will be used to degrease and pre-clean the piping prior to true chemical surface treatment. Pickling will remove undesirable oxide layers at heat affected zones, and passivation will restore the protective chromium oxide “layer’ which gives these alloys their stainless character. Intermediate rinsing with demineralised water between and after each phase is necessary to remove all chemical residues.
In some cases the chemicals and water are introduced and circulated through the piping using pumps, hoses and tanks temporarily attached for cleaning purposes. This is described as in-situ or on-site cleaning. In other cases pipe spools prefabricated to convenient lengths can be transported to the workshop for cleaning by immersion in tanks.
For carbon steel piping the same is generally true, although the final passivation treatment is by definition temporary in nature, since carbon steel is not stainless.
Large equipment such as tanks, heat exchangers and boilers will be chemically cleaned on site. Tanks and heat exchangers may be of stainless or carbon steel construction while boilers will be of carbon steel construction. According to available fittings and other possibilities, the required chemicals will be applied by circulation using pumps.
In all cases, chemical waste will be generated. For workshop chemical cleaning, Metal Treatment Technology (S) PL has at its disposal it own waste treatment plant. For waste generated on site, there are two options. Either the waste is transported as-is to an approved waste disposal facility, or it is treated on-site to acceptable standards before disposal to the client’s own disposal facility. Metal Treatment Technology (S) PL is aware of environmental requirements and complies with these.
Occasionally forms of pre-commissional chemical cleaning need to be performed other than pickling and passivation. For example, piping and valves destined for oxygen service have to be 100% oil and grease-free. This can be done by the application of speciality solvents, which are recovered for regeneration. Metal Treatment Technology (S) PL has performed such work, both on-site and in the Singapore workshop.
2.2 MAINTENANCE CHEMICAL CLEANING
This type of work can be sub-divided into two. Maintenance or periodic cleaning of utility systems such as boilers and cooling water circuits; and process chemical cleaning where specific product residues are removed to “rejuvenate’ the equipment in question.
In the first case, the reason for chemical cleaning is usually to remove scale build-up in piping and equipment. The type of scale can vary from water-borne scaling components such as calcium carbonate to water-steel reaction products such as magnetite Fe3O4 in high-pressure boilers. The chemicals used and their methods of application will vary according to requirements. Standard procedures will apply when the identity of the contamination to be removed is known without a doubt. In all other cases, samples are obtained to derive efficient cleaning methods. It should also be noted here that in the case of boilers, extensive re-tubing may be done following failures or after the identification of potential failures such as tube wall thinning. Again, after the re-tubing, the whole boiler will be chemically cleaned to achieve a uniform surface finish. To omit the chemical cleaning would result in the enhanced potential for future corrosion in the boiler.
In the case of process chemical cleaning the work is always job-specific and will not be done by reference to a standard procedure. Samples of process residues will be used as a base for generated procedures.
Commonly, in the case of stainless steel, maintenance chemical cleaning is done to restore a uniform passivity on the surface. A good example is the case of marine cargo tanks and piping systems. Where pitting has occurred due to one or more of several operational malpractices, this has to be repaired. The steel is then pickled and passivated so that the whole surface obtains uniform corrosion resistance. Industrially, stainless steel piping systems are commonly adapted for the introduction of new equipment or some other revision. Again, the uniformity of the passivity is achieved by re-pickling and re-passivation of the whole system.
Metal Treatment Technology (S) PL has experience in both pre-commissional and maintenance chemical cleaning.
3. RANGE OF PRODUCTS SUPPLIED
Metal Treatment Technology (S) PL can supply a wide range of products for both the marine and industrial sectors. They can be divided into two main groups, namely cleaning/surface finishing products and maintenance products.
3.1 CLEANING/SURFACE FINISHING PRODUCTS
Similar to chemical cleaning itself, these products offer customers a way to treat the surface in question in several ways:-
- Water-based degreasers are designed to remove oils and greases in an aqueous environment. According to the nature of the oil or grease to be removed, and with reference to the underlying material, they come in several forms. Heavy-duty alkaline degreasers are used at elevated temperatures for removal of animal and vegetable oils from carbon steel and stainless steel. Mild alkaline degreasers combined with other ingredients can be used for both animal, vegetable and mineral oil deposits on several metals, while neutral water-soluble solvent-based degreaser are used for a wide range of oils and greases on almost any surface.
- Solvent-based emulsifiable degreasers are used either in pure form or in water for the removal of mineral oil deposits, usually from tanks.
- Acidic descalers are used for removal of water-borne scaling contaminants. Heavy-duty versions are used on carbon steel surfaces, while organic acid based products can safely be used on stainless steel.
- Acid pickling products can be used on stainless steel for removal of oxides at heat-affected zones, while acid-passivating products will passivate the pickled steel.
3.2 MAINTENANCE PRODUCTS
As a counterpoint to chemical cleaning, Metal Treatment Technology (S) PL offers a range of maintenance products for customers wishing to minimize scaling or corrosion in their systems. The commonest areas of application are cooling water systems and boilers.
All products offered by Metal Treatment Technology (S) PL fall under the chemeast range.
Metal Treatment Technology (S) PL employs staff with an international background. Without referring to academic achievements, the Metal Treatment Technology (S) PL chemical cleaning and product specialists have the added qualifications of versatility and experience. Staff hails from Singapore and the UK.