CS251525B1 - A method for removing unwanted solids from heavy pyrolysis oils, resins, or heavy tar fractions - Google Patents

Abstract

Method for removing unwanted solid components from heavy pyrolysis oils, resins, or heavy fractions of tars for the preparation of demanding carbon products, such as needle coke, carbon fibers, etc. The method is characterized in that the starting pyrolysis oil, resin, or heavy fractions of black coal tars are dissolved in 1 to 10 times the amount of solvents, which are liquid aromatic hydrocarbons, their homologues, ethers, ketones, or low-substituted chlorinated derivatives, or mixtures thereof. Then the suspended components are removed from the solutions by centrifugation in a sedimentation centrifuge at a speed of 2,000 revolutions per minute. Finally, the used solvent is removed by distillation, the content of unwanted solid components in the treated resin decreases by 60% compared to the original.

Description

251523

It is an object of the present invention to provide a method for removing undesired solid constituents of heavy pyrolysis oils, resins, or heavy tar fractions to prepare sophisticated carbon products. Heavy pyrolysis oils and resins are by-products of oil processing, or some of its fractions or tars. Alcohol residues are obtained after the distillation of the easier, more valuable pyrolysis products. This means that they are the last minor, respectively. waste product of chemical and separation processes. Into their composition, the impurities of the starting materials pass, the "crops of pyrolysis". and the products of their secondary reactions resulting from the high temperature distillation. In the distillation of sati, the constituents concentrate and determine the properties of the distillation residues and the possibilities of processing.

Very important undesirable constituent pyrolysis products are solids dispersed in the form of very fine particles. These are mainly made of ash, grain-size coke and polofcoks. Their content is one of the decisive factors determining the properties of the oils, respectively. Living and limiting the possibilities of light processing more demanding products.

Heavy pyrolysis products, with respect to their composition and hence their properties, are generally inefficient as fuel, or asphalts or substitutes, or are processed into sparse carbonaceous materials, or are interchangeable with other materials. they accumulate on ecologically dangerous dumps. Only a small portion of the heavy pyrolysis products are processed into more valuable types of articles such as carbon dioxide, carbon fibers and the like.

The requirements of more demanding production, low solids content in pyrolysis oilseeds are still solved by most of the choice of a suitable oil or resin without the content of solids, or with their low content, fcto or not disturbing the process or can be modified. reduce to a load bearing capacity. In principle, the reduction of the solids content can be ensured by various methods utilizing sedimentation, filtration, extraction, and any of these methods can naturally reduce some of the solids. Their practical application for the special case of removing solids from heavy pyrolysis. oils and resins, respectively. however, tar is faced with a number of technical obstacles to limiting the upper limit of the content, when the heavy pyro-lysine product being processed can still be treated

The technical problems arise from the properties of the separated substances and the system. In particular, pyrolysis oils and resins or moles are highly viscous at normal temperature. Furthermore, the particles of solid constituents are very small. Their diameter is in the wide range of about 1.0 µm. In addition, the difference between the density of the solids and the liquid or liquid particles is also small. meltable pyrolytic oil nibs.

These properties make it difficult or impossible for successful use of separation processes to reduce the achievable separation effect. Fiiltration and sedimentation, respectively. centrifugation can only be carried out at elevated temperature. Extraction leads to the release of solids into the extraction solution. Therefore, the actual extraction must be supplemented by other methods of separation. This process has found wider application only by vanalytical conversion. In the preparative, respectively. By virtue of the practical application of the invention, only the filtration is limited to the use of low solids resins.

Despite these limitations, it has been possible to provide a method for removing substantially the solids from pyrolysis oils, resins, or heavy black coal breaths.

It has been found that the undesirable solid components of heavy pyrolysis oils, resins or heavy black coal fractions to prepare sophisticated carbon products can be removed according to the invention by dissolving the starting purified pyrolysis oil, tar or heavy tar fraction with 1 to M-number of solvents, which are liquid aromatic hydrocarbons, homologs, ethers, ketones or low-substituted chloro derivatives, or mixtures thereof, are then suspended suspended insolubilizers from the solutions by centrifugation in a sedimentation centrifuge at a speed of 2,000 rpm, and the solvent used is removed by distillation.

The described process is easy to implement and provides a decrease in the solids content of the resin to below 1%. In this case, the particles having a particle size above 10 [mu] m are virtually completely removed. In addition, the method extends the range of available pyrolysis raw materials by using pyrolysis raw materials with a primary solids content of up to 10% and in the case of repetitive centrifugation. with a higher content of impurities.

In selecting the conditions for removing solid constituents, some aspects in the properties of the separated substances and systems must be taken into account. This relates to the selection of solvents and the conditions for carrying out the operations in such a way that the desired degree of separation without negative effect on the further processing of the resins of the desired products is obtained.

In particular, the solvents selected and / or solvent requirements must satisfy several requirements: - they must dissolve the predominant proportion of the desired substances from the pyrolysis raw materials, 251525 5 - the prepared solutions should have a low density, - the solutions must have a relatively low viscosity in order to they can be centrifuged at normal or only slightly elevated], they are to be low flammability and low volatility under conditions of dilution, - they must be removed from the resin prior to its further treatment and re-generated, - they should not be they should not be toxic - harmful to health, - be available and hungry.

The criteria exchanged above preclude the use of certain groups of solvents. Aliphatic hydrocarbons and the opposite and strong polarities do not dissolve the heavy particles of pyrolysis prodrugs and can only be present in small amounts as impurities in the rotary blowers used.

Halogenated hydrocarbons do not reduce the requirement for low density. More complex solvents do not interfere with several criteria (such as low viscosity requirements of the solutions, low density, inertia to pyrolysis, easy removal from solution after centrifugation of solids, and others. In addition, the use of light aromatic hydrocarbons is also limited by high The exclusion procedure thus allows the selection of solvents according to the subject matter of the present invention.

To the experimental study of solubility-heavy pyrolysis substances and prodrugs of their further modification and solubility of their various parts, much attention has been paid so far to the analytical use of the theoretical interpretation of the results. These studies are directed predominantly to the selective solubility of the various components of the pyrolysis oils and tars in the light solvents or in their defined proportions. The unique work of natechnologic use of similar solutions - in light solvents - has directed the selective separation of various soluble meltable resin components.

The use of heavy pyrolysis prodrugs, even in conjunction with centrifugation, removes their solid constituents from the netol described below.

The ratio of the amount of solvents to the amount of purified substances is determined by similar requirements as the determination of the solvent type, i.e., the effort to reduce the viscosity and density of the solutions, the feasibility of centrifugation with the desired low temperature, and the manageability of solvent removal without adversely affecting the further processing of the resin. In addition, there is a need to optimize counter-requirements to achieve a high solvent dilution effect and a favorable separation result compared to the favorable utilization of capacitance equipment and to minimize solvents that have to be removed by distillation after the resin is separated. In view of the variety of substances which are suitable for the application of the proposed purification process, it is necessary to determine optimally the amount of solvents separately for each of the materials.

A method for removing solids from pyrolysis oils and resins, or from heavy coal tar fractions, demonstrates the following examples: EXAMPLE 1 100 g of heavy pyrolysis oil was dissolved in 300 ml of toluene. From the prepared solution, 50 ml was dispensed into the laboratory centrifuge tubes. After centrifugation at 3000 rpm for half an hour, a substantial portion of the solids deposited on the bottom of the cells from the centrifuged solution. Further portions, despite the clear displacement of the crescent in the centrifugal field, formed a scattered layer in which the density of the solids Ik level dropped. This layer occupied a significant portion of the volume flow and was agitated when the solution moved. By sucking off the topsheet, about 50-60% of the solution is obtained with a very high solids content.

The waste of unpurified solution is very high at this conversion. Centrifugation with open acetides showed an appreciable solvent loss. It should be inferred from this that the use of lighter volatile solvents is risky in terms of fire hazard. Example 2

A similar alcohol was used, with the difference that different solvents were used for the preparation of the solution of the solution: a) xylene, it) benzene, cj anisole, d) phenetol, acetylphenone, f ') tetralin, g) mixture: tetralin -90%; and naphtha-bv 140-170 ° C; 10%; h) tetralin 90 ° / benzobenzene 10%; i) tetralin 80% anaphthalene 20%.

Resin solutions in these solvents were similar in centrifugation to Example 1, with the solvents less volatile; density increase is reflected in 251525 «sedimentation of solids particles.

Mixture: tetraline-naphthalene is a model of a regenerated, partially purified solvent in which a portion of the volatile oil is present after the solvent has been used. EXAMPLE 3 Heavy Pyrolysis Oil in Amounts a) 100 g are dissolved in various amounts of tetralin in proportions per 100 g of oil: a) 100 ml, b) 200 ml, 300 ml, d) 500 ml, 1000 ml, 50 ml.

The solutions were centrifuged as in Example 1. Problems with slow sedimentation were observed only in Examples a, f. An initial temperature of 60 ° C was chosen. Settling of diluted solutions was effective. The yield after evaporation of the solvents was obviously low, which does not meet the requirements of pre-technological use. Example 4

After 20 kg of heavy pyrolysis oil containing 2.47% solid impurities, a) was dissolved in 40 l of tetralin, b) 80 l of tetralin.

The solutions were centrifuged in a continuous centrifuge at 8,000 rpm for 0.8 l / min. From the centrifuged solutions, tetralin and volatile materials were distilled off. The obtained distillation residues - approx. 10 [mu] g - useful for further processing to demanding products contained less than 1% solids. Centrifugation is easier to control with dilute solution. On the contrary, Despilacla also lasted longer in this case. Example 5 A mixture of 3 .mu.g of heavy pyrolysis oil was prepared with a solids content of 2.47% and 9 l of tetralin. The mixture was centrifuged on a laboratory sedimentation centrifuge for a flow system at 3000 rpm with 80 ml / min dosing. The solvent was then distilled off the solution. and the volatile portions of the resin. The distillation residue contained less than 1% solids. Example 6

The procedure was as in Example 4, except that the centrifuge was treated by filtration. Despite the thicker stitching and the fabric solution, it also passed with the resuspended solid component of the resin. Sewn with fine otivore, eg. 12.6 μηι were quickly impregnated with an impermeable filter cake. Example 7 Heavy pyrolysis oil starting with 3.54% solids was dissolved in twice the amount of tetralin 95% and 5% naphthalene. The mixed solution was centrifuged on a continuous centrifuge at a speed of 8:00 rpm. The high solids content of the starting oil in this process resulted in the formation of hard composite deposits which were freely released and aggravated by the centrifugation of the centrifuge drum. Example 8

The procedure was similar to that in Example 6. In contrast to this, the centrifugation was carried out twice, at the first at a speed of 3,000 [mu] t / min and then at an increased speed of 8,000 rpm. Centrifugation by this procedure resulted in distillation of 1 k of the product with a solids content below 1%. Example 9 From a heavy pyrolysis oil with a starting content of 3.54% solid impurities by sedimentation at a mud temperature of 340 ° C. ° Ο removed volatile components. The residual residue is about 60%. Of this, 3 were dissolved in 20 l of tetralin. Centrifugation and distillation of the solvent resulted in a product with a solids content below 1%. Using a solution of 3 kg of the substance in 10 ml of tetralubole needed to centrifuge the solution twice. EXAMPLE 10 3 kg of black pitch were dissolved in 30 l of tetralin, containing 14% insoluble components, including insoluble, highly aromatic, organic substances. The solution was centrifuged twice at 80 ml / min, and at speeds of 4,000 and 8OO10 revolutions per second. minute. The solids content of the solvent evaporation was approximately 1%.

Claims (1)

SUBJECT Process for removing unwanted solids from heavy pyrosis oils, resins, or heavy tar fractions for the preparation of sophisticated carbon products, characterized in that the initial purified pyrolysis oil, resin, or heavy tar fraction is dissolved in 1-10 times the amount of solvents that are liquid aromatic uhloVYNÁLEZU hydrogen, their homologues, ethers, ketones, or low-substituted chloro derivatives, or mixtures thereof, and then resuspended insoluble components are removed from the solution by centrifugation at sedime.ntačnej centrifuge at a speed of 2000 ^min-1, and finally removed by distillation used solvent.