SU893902A1 - System for waste water purification - Google Patents

Description

(54) SYSTEM FOR CLEANING WASTE WATER

one

The invention is intended to create a closed cycle of water circulation in paper production with a degree of sizing of more than 1.25 mm and can be used in the pulp and paper, chemical and other industries.

A known system of a closed cycle of water circulation, in which the purification of excess circulating water takes place at one stage, including a collection of registered and excess water sequentially installed and interconnected, and the device FOR clarifying circulating water til.

However, the degree of clarification of the water is insufficient, and therefore such poorly clarified water is suitable for use only on sprinkles of the net and not all structures, but fresh water is used in the remaining areas, so the reduction of its consumption is practically not large.

The closest in technical essence to the present invention is a system in which purification of water is carried out in two stages. The system contains sequentially installed and interconnected collection of river water, collections of excess

water, a device for clarifying recycled water, a device for injecting chemicals, a device for deep cleaning of clarified water, a collection of deeply clarified water and an accumulating collection of industrial water.

Water from the register water collector is used to dilute the mass. Excess water through overflow enters

10 in the collection of excess water. Further, this water is partially used in the mass preparation section, and most of it goes to the device for clarifying the circulating water. After which part

15 water is collected in the accumulator collection and used in the system of mass preparation, and some are treated with chemical reagents (aluminum sulfate and alkali hydroxides) with

20 to intensify the purification of clarified water on the devices for its deep cleaning (second degree). Deep clarified water is partially used in net

25 parts of the machine, and partially sent to a collection of deeply clarified water, where they are mixed with fresh water and then fed into the production t2.

During repeated circulation of water 30 in the system under consideration using the above chemicals, a process of accumulation of soluble mineral components in the production water is observed, which violates the paper sizing mode and degrades the quality of the finished product. In addition, there are no installations for cooling water in the system, which also leads to a decrease in the quality of sizing and disruption of equipment operation mode. It should also be noted that this system does not allow for the use of water from the pressing, finishing part of the machine, heat exchangers for various purposes, etc.

The purpose of the invention is to increase the degree of wastewater treatment of paper production with a sizing degree of 1.25 mm and reduce water consumption.

The goal is achieved by the fact that a system for treating wastewater generated during operation of a paper machine, comprising sequentially installed and interconnected a collection of register water, a collection of excess water, devices for clarifying recycled water and purifying clarified water and a collection of clarified water, equipped with a demineralization unit installed between devices for clarifying circulating water and purifying clarified water. The system is equipped with a cooling unit with excess clarified water and an accumulating collection of chilled production water connected in series and interconnected, the latter being connected to a papermaking machine, and the cooling unit with a collection of clarified water.

The drawing shows a diagram of the proposed system.

The system includes a machine pool 1, mass cleaning unit 2, grid part 3, press part 4, drying and finishing part 5, vacuum pumps 6, water separators 7 and heat exchangers 8, collection of 9 registered waters, collection of 10 excess water, device 11 for clarifying circulating water , unit 12 for demineralization of clarified water and registration of chemicals (complexones), collection 13 of deminera. lye clarified water, device 14 for deep purification of clarified water, collection 15 of deeply clarified water, cooling unit 16 dy, accumulating a collection of 17, a collection of 18 of warm filtered water ..

The accumulator collection 17 is associated with vacuum pumps 6 and heat exchangers 8. Heat exchangers 8 are connected with collection 18 of thermal filtered water, which is connected to the grid part 3 and the press section .4 of the machine, collection 19 of fiber-containing waters of the grid part, collection 20 of pile-containing water from the press section , fractionator 21.

The system works as follows

Registered water is used to dilute the mass, and its excess enters the excess water collector 10, from which water goes to the device 11 to clarify the circulating water. The clarified water enters the demineralization unit 12, and the clot is sent to the mass preparation system ..

Chemical reagents (complexones) are introduced into the demineralization unit to ensure the removal of soluble mineral components, in particular sulfates, from clarified water.

Prepared in this way, it is industrial, and water can circulate many times in the system and be used as a medium for sizing paper pulp without having a negative effect on the sizing process mechanism and its efficiency.

The clarified demineralized water is collected in a collector 13 and is used to dilute the mass and as a spray water in the cleaning unit 2, the mesh part, 3, on the mesh and mesh rollers, in the mass preparation system. Excess demineralized clarified water enters the device 14 for deep purification of clarified water. The clot is withdrawn from the system, and the deeply clarified water is collected in the collector 15, from where part of the water is used on the hydraulic cut-offs and the transfer of the spray part of the grid part 3, and the excess enters the cooling unit 16, after which it is accumulated in the collector 17. from collection 17 it is used as a coolant in heat exchangers 8 for various purposes and for feeding vacuum pumps; owls 6.

The scheme provides for separate removal of pile-containing water in the wet. 0 parts of the machine (3 and 4), while the water, from the collection 19 of fiber-containing 6D and the collection of 9 registered waters, and the pile of water, is completely withdrawn from the system.

The proposed system provides deeper water purification from impurities, the content of impurities in purified water is mg / l:

.. We offer the known system on a weighted,

Significant substances 10-15 20-30

Claims (2)

Dissolved organic matter, MgO | 2 / l 50-100 Mineral 50-100 1000-1500 salt Thus, the proposed system allows for a closed cycle of water circulation with the release of high-quality, highly glued paper, using almost all of the paper machine flow. With the release of highly glued paper types (writing, offset, illumination, etc.), the actual media annual flow of fresh water is approximately 85, i.e. the system allows to reduce the consumption of fresh water to 5, the amount of wastewater discharged into the water by 80. Claims 1. A system for treating wastewater generated by the operation of a papermaking machine, comprising a sequentially installed and interconnected collection of registered water. collection of excess water for installation; for clarification of circulating water and purification of clarified water and collection of clarified water, characterized in that, in order to increase the degree of purification of waste water from paper production with 1.25 mm sizing fluid and to reduce water consumption, the system is equipped with a demineralization unit installed between devices for clarifying circulating water and purifying clarified water. 2, the system of claim 1, characterized in that it is equipped with a cooling unit with excess clarified water sequentially mounted and connected to each other and an accumulating collection of cooled industrial water, the latter being connected to a papermaking machine and the cooling unit to a collection of clarified water . Sources of information taken into account in the examination. 1.Paper and cellulose. Issue Foreign technology, M., 1961, 15, p. 3-) 18. 2. The patent of Sweden 382491, cl, O 21 F 1/66, 1977.