RU2220879C1 - Method of cleaning flushing and under-floor water - Google Patents

Abstract

FIELD: operation of ships and oil storages ashore. SUBSTANCE: proposed method includes washing the shipboard tank with water or with water and reagents followed by discharge of flushing water. Flushing and under-floor water is accumulated , kept for 0.5 to 5 h and is neutralized in working zone and is neutralized in presence of reagents-oxidants for conversion of dissolved and floating petroleum products into water-insoluble compounds at higher specific gravity as compared with water. These compounds settle at high rate forming inactive sludge at accurate interface. Water and sludge are kept for 0.1 to 5 h kept for 0.1-5 h; cleaned water is discharged and inactive sludge is mixed with petroleum products. Mixture thus obtained is treated in activation plant for production of furnace fuel. NaClO or CaOCl₂ may be used as reagent-oxidant. For treatment of water, use may be made of shipboard tank. EFFECT: enhanced efficiency. 4 cl, 1 dwg

Description

 The invention relates to the field of servicing vessels of the oil fleet, but can be used to service ships of any purpose and oil storage facilities onshore.

 Currently, oil-loading vessels experience difficulties when flushing empty tanks, since flushing water containing large amounts of oil products (oil) is strictly forbidden to be discharged into port waters, and they are reluctant to take them to urban wastewater treatment plants, and processing onshore is expensive. As a result, oil-containing flushing water must be discharged away from ports, which is extremely undesirable from an environmental point of view.

 The deposition of spilled oil and oil film by chemical purification (active chlorine, bleach, etc.) is used (Chemical Encyclopedia: 5 t.: T. 3: Honey - Paul / Editorial: Knunyants I.L. (Ch. Ed. .) and others. - M .: Big Russian Encycl., 1992, p. 344-435). This method is especially dangerous and can be used only in emergency cases, as it completely destroys the entire bottom flora and fauna of the sea.

 At present, there is almost no information on the use of active methods of neutralizing flushing waters formed on oil-loading fleet ships and especially under-saturated bilge water.

 A known method of purification of sub-bore water SU 220074, B 63 B 57/00, 06/14/1968, which consists in using a filter system for coarse and fine purification, sedimentation of sub-bore water, their evaporation and subsequent burning of residual oil and sludge in the tank of the vessel.

 The fire method has significant drawbacks.

 1. A large fuel consumption (250 ÷ 300 kg of standard fuel per 1 ton of effluent) is required for the evaporation of water and the complete combustion of toxic impurities.

 2. Both very low and very high temperatures are necessary for conducting processes.

 3. Difficulties in disposal, as it requires special production, equipped with sophisticated equipment.

 A known method of cleaning marine fuel tanks, RU 99111617, B 63 B 57/00, 04/27/2001, which consists in sequential washing of the vessel’s tanks with a detergent composition containing flooded oil fuel with a surface-active substance, collecting sludge from the washing composition in the sump and repeatedly washing the tanks . This method is closest to the claimed invention, but has a number of significant drawbacks. To implement the method requires a large amount of water, which subsequently also needs to be cleaned, the method is time consuming and requires a lot of time; the impossibility of purification of sub-bore water of ships

 The objective of the invention is the complete purification of wash water from oil products, their capture and neutralization; purification of the sub-bore water of the vessels, processing on the vessel of the same captured products and obtaining, on their basis, industrial heating oil suitable for use, for example, in boiler houses.

 The technical result is achieved as follows.

 The method of purification of washing and base water on oil vessels, includes washing the tank with water or water with reagents and discharging treated water. Wash and bilge water is collected and kept for 0.5-5 hours, neutralized in the working area of the process activation unit in the presence of oxidizing agents to convert dissolved and floating oil products into water-insoluble compounds that have a higher specific gravity compared to water and settle with high speed with the formation of inactive sludge, forming a clear interface between water and sludge. Then stand for 0.1-5 hours and dump purified water. After that, the inactive sludge is mixed with petroleum products and the resulting mixture is processed in a process activation unit to produce heating oil.

As the oxidizing reagent, NaClO or CaOCl _{2 is used} .

 A free tank of the vessel is used to collect and settle the wash and bilge water before its treatment.

 For sludge and collection of sludge use the second free tank of the vessel.

After washing the vessel’s tanks, water contaminated with oil products is collected in one of the tanks, incubated for 0.5-5 hours, which is sufficient to separate the main part of oil products, and then neutralized in a process activation unit with the addition of calcium hypochlorites CaOCl ₂ or sodium NaClO. In this case, NaClO is preferable since, as a result of neutralization reactions, only bound petroleum products are found in the sludge, and in the solution are sodium and chlorine compounds, which does not affect the composition of sea water. Moreover, the pumping of contaminated water is carried out by the pump from below. At the same time, the layer of oil products smoothly descends downward, almost without mixing with water. After pumping out contaminated water, the oil layer from the bottom of the tank is pumped to the collection tank with the same pump.

 In the working area of the process activation apparatus, fast and complete neutralization of the wash and bilge water occurs, while free and dissolved petroleum products pass into insoluble compounds. The resulting suspension acquires the ability to separate at a very high speed. So in 5-15 minutes more than 95% of the total mass of the solid phase settles. After an exposure of 3-5 hours, the water becomes completely transparent and enters another free tank, where sludge is separated.

 After a given exposure, the clarified water is dumped overboard, and the sludge is pumped into the same collector where the settled oil was collected, where they mix well. After some exposure, or without it, the mixture is passed through a process activation unit and returned to the same collection tank. The result is a high-quality fuel that can be sold.

 Substrate waters, which are known to be highly contaminated, can be neutralized in the same way. It is better to clean them during the next tank washings. No alterations are required to organize flushing, and existing pumps can be used. Additional equipment is 1 or 2 process activation units (UAP), a collection tank and 2-3 tanks for reagents.

 The size of the UAP, the collection tank and the tanks for reagents is small, and they can be installed without difficulty on the deck or any suitable room.

 Thus, a tanker vessel can flush tanks of oil products without leaving the port and without wasting time and energy on the crossings.

 The drawing shows a layout of equipment for implementing this method.

 To carry out neutralization, you will need two any freed tanks. The engine room 1 is involved, in which the under-shale water 2 is accumulated with a pump 3 for pumping water, a tank 4, into which the wash water is drained. After sludge, a layer of oil 5 accumulates in the upper part of tank 4. When pumping wash water, this layer decreases and is pumped out last and takes position 6. In tank 7, treated water is sedimented, sediment 8 falls to the bottom. Tank 9 is free.

 The neutralization system consists of a pump 10, a collection tank of settled oil 11, tanks for reagents 12 and 13, a process activation unit 14, pump 15.

 The process is as follows. Flushing water from all tanks is pumped into tank 4, and aging is performed for a predetermined time. The bulk of the oil (oil products) settles and occupies position 5. The selection of contaminated water is carried out from the bottom of the tank by pump 10, which is processed in UAP 14, adding, if necessary, reagents from tanks 12 and 13.

 Treated water is discharged into tank 7 for sludge. The sludge settles and takes position 8. After exposure, the specified time sludge in the form of sludge is pumped by pump 15 into the collector 11, and clarified water is dumped overboard. As 11 petroleum waste and sludge accumulate in the tank (the sludge is also petroleum products), they settle, and the water is flushed into tank 4 during the next washing. When filling the tank 11, the resulting mixture of water and petroleum products is passed through the UAP 14–2 times and receive high-quality heating oil, not inferior in calorific value to fuel oil.

 The sub-shale water 3 is pumped by pump 2 into the working area of UAP 14, where they are treated with the addition of reagents from tanks 12 and 13 and dumped into tank 7 for sedimentation. The specified operation is performed during the next wash.

Example
To neutralize the oily waters, the waters of the Tuapse seaport were used, which are sent to neutralization in urban facilities.

 The initial oil content in the water was 8 mg / L. The neutralization was carried out as follows. Water was sedimented in the tank for 30 minutes. A thin film of oil products formed on the surface. Since there were few oil products, the film was not taken into account and all the waters were sent to the UAP in a continuous stream. In front of the apparatus, a NaClO solution was introduced into the water based on the theoretically necessary amount for the processing of petroleum products.

 After processing, the resulting suspension was left to stand for 1 h. About 95% of the total mass of the solid phase precipitated in the first 5 minutes. After 1 hour, the water became clear. The oil content after neutralization was 0.8 mg / l, which is lower than the MPC.

 For work, the UAP-3 apparatus was used.

 Depending on the displacement of the vessel and, accordingly, the volume of flushing water, 1-3 UAP apparatuses of various capacities will be required. Currently, there are several types of UAP type devices.

 It has been established that process activation apparatus with equal success neutralize water with any content of petroleum products.

Claims (4)

1. The method of purification of washing and bilge water on oil vessels, including washing the tank with water or water with reagents and discharging purified water, characterized in that the washing and bilge water is collected and maintained for 0.5-5 hours, neutralized in the working area process activation plants in the presence of oxidizing reagents for converting dissolved and floating petroleum products into water-insoluble compounds with a higher specific gravity compared to water and settling at a high rate with inactive formation sludge, forming a clear interface between water and sludge, incubated for 0.1-5 hours, discharged purified water, and then inactive sludge is mixed with petroleum products and the resulting mixture is processed in a process activation unit to obtain heating oil. 2. The method according to claim 1, characterized in that NaClO or CaOCl _{2 is} used as an oxidizing agent. 3. The method according to any one of the preceding paragraphs, characterized in that a free tank of the vessel is used to collect and settle the wash and bilge water before treatment. 4. The method according to any one of the preceding paragraphs, characterized in that for the sludge and collection of sludge using the second free tank of the vessel.