Tank Cleaning Dallas-Fort Worth, Texas

Applicability

tank_cleaningMantis Environmental provides Texas tank cleaning and vessel cleaning services for various types of tanks for all categories of industry. Frac tanks are utilized in many industries but are concentrated in the oil field. Mantis can offer turn-key solutions for frac tank cleaning.

We clean above ground storage tanks of all sizes and contents. We can offer a superior service through proper planning and unparalleled attention to safety and cost.

Rail car cleaning and Intermodal cleaning are also part of the Mantis service offering. We offer innovative solutions that minimize human entry at all times. When entry is required state of the art, confined space entry protocol is followed at all times.

Planning

Many factors need to be considered in order to achieve the desired tank cleaning result. Planninga tank cleaning operation is the key to success. Planning should be carried out by qualified people only.

A good preparation of the cleaning operation will avoid tank rejections as well as incidents during the operation. In general the tank cleaning procedure can be determined from the product properties of the product to be cleaned, the surrounding conditions and the available equipment.

Physical properties

tank_cleaning_1The physical properties of the material being cleaned will dictate a large portion of the cleaning technique employed as well as specific safety procedures needed.

Water-Soluble or Water-Miscible products: Water-Soluble substances and water-miscible substances are easy to clean with water, and the solubility of the substances might increase at higher temperatures. The use of a cleaning agent is only advisable for reduction of the cleaning time.

Products with a high melting Point: These products should be washed at a temperature of 15-20 C above the melting point. During cleaning special attention must be given to liquid and vapor line systems to avoid freezing/solidification at cold line segments. Washing as soon as possible after discharge is recommended.

Products with a high viscosity: These products should be washed at higher temperatures. In general the viscosity is closely related to the temperature and will decrease at higher temperatures. Washing as soon as possible after discharge is recommended.

Vapor Pressure/Boiling Point: Products with a high vapor pressure (higher than some 50 mbar at 20 C) can be removed from the tank by evaporation. As always during ventilation, special care must be taken to prevent the risk of explosion (flammable products) and emission (toxic vapors). All safety and environmental precautions must be taken.

Flash Point/Flammable Range: The flashpoint is the lowest temperature at which a product gives off sufficient gas to form a flammable gas mixture that can be ignited. The pre-cleaning temperature must be well below the flashpoint. If this is not possible, avoid any ignition source.

Density / Specific Gravity: Is the ratio of the mass of a volume of a product to the mass of an equal volume of freshwater (1.0). For a product with limited or no solubility in water the specific gravity indicates whether the product will float on water or sink.

Cargo Characteristics

Polymerization: The initial wash of products that tend to polymerize should be carried out with cold (ambient) water. Washing with hot water may result in polymeric residues being left in tanks and lines, which are very difficult to remove.

Evaporation of volatile substances: Tanks consisting of mixtures with different vapor pressures should neither be cleaned by evaporation, nor prewashed hot. The evaporation of the light substances from a mixture could result in non-volatile residues, which are very difficult to remove.

Reaction with water: Isocyanates must never come into contact with water, not even the residues, because the reaction product and insoluble urethane (plus CO2) are very difficult to remove. Such products must be washed with a suitable solvent, that does not contain any water.

Reaction with Oxygen: Drying and semi-drying vegetable and animal oils react with oxygen to form a varnish-like polymeric film. This is very difficult to remove. Since heat increases the reaction speed the initial washing of these products must be done with water at ambient temperature without any delay after emptying tank.

Reaction with water hardness compounds: Water hardness is formed by the calcium and magnesium content of the water. Some products like fatty acids and vegetable oils with a high free fatty acid content will form white sticky residues, if they are cleaned with a water of a high water hardness.

Smell: Minor residues of a smell-producing cargo left in lines, valves and pumps (including pump cofferdams) can be a nuisance. To neutralize the smell of some chemicals (e.g. Acrylate, Nitrobenzene or Pygas) the use of a smell killer may be recommended.

Ambient conditions

The temperature during the cleaning steps is one of the most important operating parameters. It must be remembered that the temperature in the tank can be significantly influenced by the surrounding conditions. A deviation from the desired operating temperature could be caused inside from changing parameters outside of the tank.

This could have a negative impact on the desired result, such as freezing due to lower than allowed temperature or polymerization/drying due to higher than allowed temperature. The effects of the surrounding temperatures should be compensated and thoroughly controlled during the operation.

Tank Cleaning Methods

tank_cleaning_2Butterworthing: Spraying of cleaning medium (usually fresh water) onto the tank surface by means of a cleaning machine but without addition of any cleaning agent. At least one full cycle of the cleaning machine should be allowed for sufficient cleaning. Additional cycles might be necessary depending on the degree of difficulty of the cleaning operation.

Injection tank cleaning: Injection of the cleaning agent directly into the butterworth ine during butterworthing the tank. The quantity to be injected depends on the consumption of the cleaning machines and the concentration, which is usually recommended by the supplier of the cleaner.

Recirculation tank cleaning: Prepare a cleaning solution. Butterworth the tank by internal recirculation. The necessary temperature can be achieved/maintained by means of heating coils, cargo heat exchangers or a butterworth heater.

Recirculation cleaning via service tank: Prepare a cleaning solution in a service tank. Butterworth the tanks to be cleaned with the solution and recirculate the water back into the service tank. Heat the solution with the tank heating coils, cargo heater or butterworth heater.

tank_cleaning_3Rinsing: Spraying of water (usually fresh water) with cleaning machine onto the tank walls in order to rinse chloride containing water and traces of contamination from the tank surface. Typically it is not necessary to run a full circle of the cleaning machine.

Vent – Mop – Dry: Ventilation in order to remove water, moisture and smell. This process is usually done by forced air circulation. If there are water pools on the tank bottom, they should be removed with a mop to reduce drying time. If the tank contents is sensitive to water or moisture, drying must be carried out very carefully.

Safety

Mantis treats all tanks as permit requiring confined spaces. This enables us to offer a consistent, compliant and extremely safe service in all cases.

If entry is required, the minimum level of protection includes air purifying respirators (APRs) with the appropriate chemical specific cartridges. However, more time than not, the Mantis crew is making entry with supplied air.

Air monitoring is conducted from the planning phase of the project through completion. Situations can change quickly so continuous monitoring is employed wherever possible.

PPE is chosen based on the permeation rate of the chemicals that may contact it. This ensures that the entrant will have adequate time to perform the duties assigned without exposure.

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