UA44296C2 - METHOD OF LIGNIN WASTE DISPOSAL - Google Patents

Abstract

The proposed method relates to treatment and utilization of lignine waste products, and can be used in the microbiological, hydrolysis and timber-chemical industries. Lignine waste products are used as sorbent for treatment of sewage waters. The treatment is accomplished in two stages. At first, sewage waters are filtrated through a layer of granulated lignine during 2-3 hours, then the used lignine layer is fluidized by air and burned together with inorganic sewerage products that are simultaneously fed into the said used layer.

Description

The invention relates to methods of utilization of lignin waste and can be used in microbiological, hydrolysis, forest chemical and other branches of industry, which have lignin waste after obtaining cellulose from wood.

To date, out of 4 million tons of lignin in Ukraine, Russia and Belarus, only 5,905 are used.

There is a known method of utilization of lignin waste as full-fledged substitutes for carbon sorbents (see the book by M.L. Chudakov.

Industrial use of lignin, M. Forest industry, 1972, p.216). In the mentioned productions, where there is lignin waste, in addition to them, a lot of wastewater with organic and inorganic substances is formed. Therefore, the use of lignin sorbents for their purification is of industrial utility. But the known method of using lignin waste for wastewater treatment, due to its scope of disclosure, did not allow to ensure its effectiveness.

There is a well-known method of using lignin as a sorbent for cleaning natural and wastewater (see the book by A.D. Smirnov

Sorptive water purification. L. Chemistry, 1982 p.85)

The disadvantage of the known method lies in its low efficiency due to the complex technology due to the need to regenerate the sorbent (lignin). Due to the cheapness of lignin (10 times cheaper than activated carbon), its regeneration is not economically feasible. The basis of this invention is the task of creating a method of processing lignin waste to increase the efficiency of their use by simplifying the processing technology. This is achieved by the fact that in the current method of lignin waste utilization using it as a sorbent for wastewater treatment, the purification is implemented in two stages: first by filtering through a layer of granulated lignin for 2-10 hours, and then the spent layer is fluidized with air and burned it with inorganic effluents, which are simultaneously fed into this spent layer, while the unburned mineral part in the form of granules and small particles is removed from the layer. The analysis of the proposed solution and analogues shows the novelty of the solution, while its essential features are a more complete two-stage utilization of lignin: first for cleaning joints by filtering them through a layer of granulated lignin for 2-10 hours, and then for cleaning inorganic joints. At the first stage, the process is carried out in the mode of a dense (immobile) layer of lignin, and at the second stage, the spent layer is fluidized with air and the effluents are burned together with the layer.

The essence of the proposed method is explained by the scheme of its implementation. The diagram shows: filter 1 with a dense layer of granulated lignin in a housing with nozzles 2 for supplying lignin, 13 - for discharging the spent layer to the second stage - into the furnace 4 for burning the layer together with inorganic effluents, a supporting gas distribution grid 5, through which from bottom to top air is blown into the fluidization of layer 1 of burning lignin in the bubbling layer b, from which the mineral part is discharged through the nozzle 7, and to which the inorganic waste is fed from above by the atomizer 8. In the upper part of the furnace 4, there is a box 9 for the output of the steam-gas mixture in the cyclone 10 for the separation of dust and ash in it. At the bottom of the furnace there is a fuel atomizer 11 for initial ignition of the layer.

An example of the implementation of the method.

First, a lignin granulated adsorbent with a granule size of 2 - 5 mm, a volume of 1 m' in the form of a dense layer, a weight of ZbOkg, a height of 1 m, a diameter of 1.15 m is loaded into the body of the filter 1 through the nozzle 2. Then, through the filter layer, wastewater with organic combustible components, for example, in the form of petroleum products, whose content in the effluents is up to 25 Ωg/l, is fed from top to bottom. The amount of waste is 40mZ/hour. Due to the developed porous structure of the lignin adsorbent and the porosity of the layer, the oil products of the effluents are filtered through the layer of lignin granules and sorbed in vapors. Due to the low specific gravity of lignin (bulk weight, Zb0Okg/m), the granules are in a floating state. After 2 - 10 hours, depending on the content of combustible organic matter and the rate of filtration of sewage, the granules lose their sorption property, their surface is covered with a film of petroleum products and other organic substances of sewage. Therefore, in this example, after 4 hours, the spent lignin layer is unloaded in the second stage - into the furnace 4 through the nozzle 3. At the same time, the layer is placed on the grid 5, and after blowing it with air from the bottom up, a boiling layer b is created. This layer is irrigated from above with inorganic effluents, for example, solutions of spent salts, acids, alkalis, which must be decontaminated by fire. The amount of such drains is 5m3/hour. To do this, the layer is first ignited with a sprayer 11, and then at a layer temperature of 700 - 12007C it burns without it. Slags in the form of granules of size 1 - Zmm are taken out of the furnace through the nozzle 7, and the steam-gas mixture and ash - through the box 9 enter the cyclone 10, where they are separated from dust and ash. After the cyclone, an air heater (conditionally not shown) is often placed in the scheme to use the heat of the outgoing times, after which the hot air is fed to the furnace 4 for burning lignin. the intensity of burning in the layer increased and due to this the efficiency of the entire scheme increases. The scheme can be adjusted for continuous operation, with constant supply and output of lignin granules from the filter 11 of the furnace 4. At the same time, the residence time of the granules in the filtration zone is up to several hours, and in the combustion zone in the furnace from 20 to 40 minutes. Due to the significant difference in the time of filtration and combustion cycles, one furnace can serve several filters.

Preliminary studies show that its implementation will increase the efficiency of lignia utilization - new waste due to a more complete two-stage process, without lignin regeneration. At the same time, environmental friendliness is ensured and various wastes, both organic and inorganic, can be cleaned. Compared to cleaning with activated carbon, the implementation of the method will allow to ensure an economic effect, the value of which depends on the amount of effluents that are cleaned.

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Claims (2)

1. The method of disposal of lignin waste, for example, after hydrolysis production: using it as a sorbent for wastewater treatment, which is distinguished by the fact that wastewater treatment is carried out in two stages: first by filtering through a layer of granular lignin for 2-10 hours, and then the spent layer is fluidized with air and burned with inorganic effluents, which are simultaneously fed into this spent layer. 2. The method according to claim 1, which differs in that the unburnt mineral part is removed from the boiling layer in the form of granules and particles.