RU2696694C1 - Process water purification method and device for its implementation - Google Patents

Abstract

FIELD: waste processing and disposal.

SUBSTANCE: group of inventions relates to processing of liquid alkaline oil-containing wastes. Process water purification method includes settling, removal of non-aqueous fractions and subsequent extraction of water phase with its distillation. Layer of aqueous phase is separated at its sludge by monitoring values of electroconductivity, fixing boundary levels of electroconductivity between non-aqueous and aqueous phases. Separated aqueous phase is heated to boiling from an additional energy source. Steam is generated, which is condensed with release of released heat energy into buffer water medium with possibility to supply heat energy to local heat consumers 12. Proposed device comprises settler 1 for waste separation, evaporator 6, buffer water tank 11 with condenser 9 and connected to it by local heat consumers 12. At upper and lower levels of water phase in settler 1 sensors 2, 3 of electroconductivity are installed with possibility to control drives of gate valves of filling 5 and drain 4 respectively.

EFFECT: group of inventions makes it possible to simplify the equipment design, to optimize power consumption, to reduce influence of harmful factors.

2 cl, 1 dwg

Description

The invention relates to methods for processing alkaline oily waste at production facilities, and can be used, for example, in the repair production of rolling stock of railways, in particular, a wheel-roller workshop.

In the car repair depot, there is an acute problem of utilization of process water generated in large quantities when washing contaminated rolling stock units. Technological water has the highest concentration and complex composition of contaminants as a result of washing wheelsets and axle boxes. After washing, the water is saturated with the components of the LZ-TsNII railway lubricant containing oil products, alkaline surfactants, as well as solid impurities washed from the surfaces of the nodes. Petroleum products are held in water in the form of a stable emulsion due to dissolved surfactants. The collection of such water is carried out in special tanks for subsequent removal for disposal, which is not performed at the enterprise. Due to the high cost of disposal of this type of waste, the depot solves the problem of reducing its volume with the help of local treatment facilities.

The prior art "Station for cleaning circulating water after washing mechanical devices" (Patent RU 2347753 from 02.27.2009 Bull. No. 6). This device uses flotation cleaning methods that require the use of a large number of reagents, as well as special qualifications of personnel for the preparation of working solutions. At the same time, soluble substances that do not react with the reagents are not removed from the water, as a result of which the degree of purification of the water discharged into the sewer is insufficient, and the volume of utilized water is reduced, all other things being equal.

The well-known "Method of wastewater treatment containing emulsified oil products" (Patent RU 2156225 from 09/20/2000 Bull. No. 26). The method consists in passing purified water through an adsorbent of a certain composition, which is the subject of the invention. This method also requires the use of consumables.

Non-reagent purification methods based on physical principles, such as osmosis or distillation, are deprived of this drawback. However, osmosis requires the use of expensive equipment and supplies, and is also ineffective in the treatment of highly concentrated waters. Distillation is devoid of all these shortcomings, but requires a large amount of energy for its conduct, which limits its use. To combat this drawback, various approaches have been developed, such as the use of waste heat, the reuse of the released energy in the distillation process, or its further application in other technological processes.

The prior art known "Device for thermodistillation water treatment" (Patent RU 2499769 from 04/27/2013 Bull. No. 33). This device uses waste heat from metallurgical processes. However, most enterprises do not have a large amount of waste heat, so this method is not suitable for widespread use.

Closest to the claimed invention is a "Device for the purification of technological or industrial wastewater" (patent No. 2429896, IPC B01D 1/28 B01D 5/00 C01F 1/04 of 09/27/2011. Bull. No. 27). A device for treating technological or industrial wastewater has an evaporator containing a heat exchanger with a tube bundle, the side with a clean distillate of which is connected to a separator to separate the distillate from the floating organic phase or similar free liquid components. The separator and the heat exchanger located in the evaporator are located and / or without bypass are connected to each other so that the liquid levels in the separator and in the evaporator are flush with each other. The separator is equipped with a level control device, which, when the liquid level drops, opens the valve to relieve pressure and closes the valve to relieve pressure when the liquid level is exceeded.

Implemented in this device, the method and the device itself are taken in the present invention as a prototype. The prototype device does not require the use of reagents, has the ability to work in automatic mode, has a reduced energy consumption

However, this method and device has the following disadvantages.

1. Since water vapor is a corrosive medium and, judging by the description, passes through the exact mechanical components of the compressor, the design of the latter must meet strict technological requirements, which leads to a high cost of equipment.

2. Vessels operating under pressure have increased strength requirements and are subject to supervision by state regulatory bodies, which also leads to an increase in the cost of their production, maintenance and cleaning of deposits. Failure to do so may result in serious emergencies.

These shortcomings can bring to nothing the economic gain from achieved through the use of a compressor unit.

The purpose of the invention is to simplify the design of equipment, optimize energy consumption, reduce the influence of harmful factors.

This goal is achieved by the fact that the method of purification of process water by sedimentation and discharge of oil products with subsequent distillation of the aqueous phase is supplemented by the fact that, according to the invention, the layer of the aqueous phase is separated during sludge by monitoring the conductivity values, fixing the boundary levels between the non-aqueous and aqueous phases by the conductivity gradients, as well as the fact that by heating the aqueous phase to a boil from an additional energy source, condensate is produced with the release of the released heat energy to the buffer water medium with zmozhnostyu heat supply local consumers; a process water purification device, made, for example, in the form of a settling tank in series for the separation of waste into liquid and solid fractions, an evaporator that provides a concentrated solution of salt and water vapor, a condenser for steam condensation and a purified water collector, while the sump with its other outlet is connected to a tank for collecting oil products; the device is supplemented, according to the invention, with a buffer water tank with local consumers of thermal energy connected to it, conductivity sensors installed at the upper and lower levels of the aqueous phase in the sludge tank, while the outputs of the upper and lower level sensors are connected respectively to the actuators of the filling and draining valves of the sump and the evaporator is also equipped with upper and lower level sensors, respectively associated with actuators of valves for filling the evaporator and the discharge of salt concentrate.

The figure shows a diagram illustrating the proposed method and device.

A device that implements a method of purifying process water, for example, purifying water from washing machines of a wheel-roller workshop of a car repair depot, contains a sump 1 with conductivity sensors of the upper 2 and lower 3 fill level, drain valves 4 and fill 5, an evaporator 6 connected to the sump 1 through the drain valve 4, and equipped with sensors of the upper 7 and lower 8 level, the condenser 9, the purified water collector 10, which is connected to the evaporator 6 through the condenser 9. The condenser 9 is placed in the buffer tank 11, filling water that transfers heat to the heat carrier to supply local heat consumers, which include both the washing machines 12 and other consumers, for example, household water supply 13 and heating systems 14. The heat carrier is heated from the water in the buffer tank in heat exchangers 15 and 16, circulating in the circuit using pumps 17 and 18. Cleaning waste, such as salt concentrate, solid fractions and oil products are collected in collectors 19, 20, 21, respectively. The diagram conventionally does not show a heat source located in the evaporator 6, which is, for example, an electric heater or heat exchanger that supplies thermal energy from fuel combustion to the evaporator.

The device operation cycle begins with the process water to be cleaned entering the sump 1 through the motorized filling valve 5, which is open in the initial state, until the conductivity sensor 2 is reached, when the conductive technological water reaches the upper level of the sump 1. According to the signal from the upper level sensor 2, the valve filling 5 is closed, and the timer starts, configured for the time required for the sedimentation of solid inclusions and the formation of a layer of oil products on the surface during phase. After it is triggered by a timer signal, the motorized drain valve 4 opens, and the electrically conductive aqueous phase, which is under the layer of oil products, flows by gravity into the evaporator 6 until its upper boundary reaches the level of the lower conductivity sensor 3. Sensor 3 is immersed in a non-conductive medium of oil products, which leads to the loss of its signal, as a result of which the motorized drain valve 4 closes. Thus, during each filling-draining cycle of the settler 1, non-conductive oil products accumulate on the surface of the electrically conductive aqueous phase, therefore, the level of their upper boundary in the filled state of the settler 1 rises relative to the conductivity sensor of the upper level 2, and at some point reaches the drain hole through which excess separated oil products flow through the pipeline into the collector 21. In the lower part of the settler 1, solid particles accumulate, which can also periodically throw in the collector 20. After filling the evaporator 6, the heating is turned on and the evaporation of water from the aqueous phase begins with the formation of a salt concentrate, which at the end of the process (when the aqueous phase reaches the low level sensor 8) is discharged into the collector 19. The water vapor released in this case flows through the pipeline to a condenser 9, condensing on its walls and displacing the formed water in a collection of purified water 10. The heat obtained by condensation is transferred through the walls of the condenser 9 to the water filling the buffer tank 11, heating it. During periods of high load on the power grid, for example, in the morning, local consumers 12 are supplied with thermal energy using a heat carrier that receives heat from the water heated in the buffer tank 11 through the heat exchanger 15 due to the circulation pump 17.

The proposed invention compares favorably with the prototype in that

- there is no compressor and other precise mechanical components that are unstable to the action of a corrosive medium (water vapor);

- the installation operates under pressure close to atmospheric, which simplifies and reduces the cost of production and maintenance of its components, reduces the danger to workers and eliminates the need for supervision by regulatory authorities;

- a clear distinction of the boundary of the aqueous phase allows you to automate the operation of the equipment by controlling the availability of water to be treated;

- reduction of the load on the power supply networks (electricity, steam) due to heat accumulation during hours of minimum load on the network for use by local consumers, for example, during peak hours;

Due to these advantages, the claimed technical result is achieved: simplification of the design, optimization of energy consumption, reduction of the influence of harmful factors.

Implementation of the proposed method and device will achieve an economic effect of the order of 2.6 million rubles per year for one typical car repair depot at prices in 2018. The economic effect consists of a reduction in the volume of waste and, accordingly, the cost of disposal (about 1.5 million rubles. per year), as well as from the transfer of energy consumption at night due to the accumulation of thermal energy with payment at a reduced rate (about 1.1 million rubles per year). Calculations of the amount of generated and utilized waste, as well as the cost of their disposal, were published by the authors in the conference proceedings (Malinovsky Yu.G., Akhmedzhanov R.A., Reutova O.A. Wastewater treatment and disposal in railway car repair depots // Omsk Scientific Readings : Materials of the All-Russian Scientific and Practical Conference (Omsk, December 11-16, 2017). Omsk: Publishing House of the Omsk State University, 2017.S. 1118-1120.).

Claims (2)

1. The method of purification of process water by sludge, removal of non-aqueous fractions and subsequent selection of the aqueous phase with distillation of the latter, characterized in that the layer of the aqueous phase is separated by sedimentation by monitoring the conductivity values, fixing the boundary levels of electrical conductivity between the non-aqueous and aqueous phases, and by heating the separated water phase to a boil from an additional energy source, water vapor is produced, which is then condensed in a condenser with the release of released heat energy to the buffer water medium with water possibility of supplying thermal energy to heat the local consumers. 2. A device that implements the method according to claim 1, containing a settling tank for separating waste, an evaporator, a condenser, characterized in that it is supplemented by a buffer water tank with a condenser placed in it and local consumers of thermal energy connected to this tank, as well as conductivity sensors, installed at the upper and lower levels of the aqueous phase in the said settler with the ability to control the actuators of the valves, respectively, filling and draining.

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