RU2117688C1 - Method for heat utilization of organic sulfurous-containing waste - Google Patents

Abstract

FIELD: utilization of organic sulfurous-containing waste. SUBSTANCE: organic sulfurous-containing waste is ground, added to fine-grain shale and heated up to 470-500 C. Said heating takes place by mixing waste with heated circulating ashes away from air. Thus obtained steam and gas mixture is fed for its purification and condensation. Hard carbonic residue is roasted and in ashes form it is returned to heating stage. It is used there as heat carrier and chemical absorbent. Thus worn tires, waste of industrial rubber, soil or sand being contaminated by hydrocarbon composition may be utilized. EFFECT: improved efficiency of the method. 4 cl

Description

 The invention relates to methods for the thermal utilization of organic waste, for example worn tires, rubber products contaminated with fuel oil from sand and soil, and can be used in the oil shale industry.

 There are various methods of thermal utilization of organic waste by gasification, pyrolysis, coking and direct burning.

 Thus, there is a known method for extracting gaseous and liquid fuels by dry distillation from used tire tires and plastic waste that have lost their practical value when they are fed to a pyrolysis unit (JP, 3.60-135481, C 10 G 1/10, 07/18/185).

 The disadvantage of this method is the impossibility of binding sulfur contained in the organic waste to be disposed of, which passes into pyrolysis gases, and the need for subsequent complex and expensive desulfurization either at the stage of formation of intermediate hydrocarbon gases, or before discharge of flue gases into the atmosphere.

 There is also known a method for the disposal of solid waste from the production of plastics, which, after grinding, is fed to a furnace for thermal decomposition in a fluidized bed of river sand. To neutralize the resulting unwanted harmful components serves special alkaline additives. Calcium oxide is used as alkaline reagent (JP, 3.57-209988, C 10 B 53/00, 1982).

 The disadvantage of this method is the need to specifically add substances that would bind sulfur and other undesirable components to the original organic waste, followed by extraction from liquid, gaseous products or from a solid residue of sulfur compounds, which is rather cumbersome and requires significant costs.

 A known method of processing organic waste, in particular waste tires, which are added to the coal mixture, going for coking. The waste is crushed, loaded into the hopper and continuously added to the coke charge in the ratio of 0.5-200% vol. on coking coal. As a result of coking from a gas-vapor mixture, a gas of 57 wt.%, 41% of liquid resins and 2% of a mixture of resin and solid phase is obtained (DE, 3.324738, C 10 B 57/04, 1984).

 The disadvantage of this process is that the sulfur contained in the waste goes into liquid products and gas, which need to be cleaned from it, and also partially goes into coke, for which the presence of sulfur is undesirable. In this case, the supply of organic waste should not exceed a stoichiometric amount adequate to additional additives to neutralize sulfur.

 Closest to the proposed method is a method of processing waste tires in a coke oven. At the same time, organic waste (JP, 3.1-95188, C 10 B 53/00, 04/13/89) is added to the operating unit that performs a specific technological task (coke production).

 The disadvantage of this process is that sulfur compounds pass into liquid and gaseous products, including coke in which the presence of sulfur is undesirable. Therefore, the resulting products must be cleaned, which requires additional material costs.

 The objective of the invention is to provide environmentally friendly waste disposal, while obtaining environmentally friendly low-sulfur liquid, gaseous fuels and chemical raw materials. In addition, the costs associated with the construction of additional purification devices or facilities, or special installations for direct burning of waste are reduced.

The task is ensured by the fact that the organic waste is crushed, added to fine-grained oil shale, the waste and shale are heated to 470 - 500 ^o C by mixing with heated circulating ash without air, resulting in a vapor-gas mixture fed for cleaning and condensation, with the formation of valuable liquid products and a solid carbon residue fed to the reduction with the formation of ash, partially returned to the heating stage and part of which with sulfur bound to neutral compounds is removed from cessa.

 As organic waste, worn tire covers are used, reinforced with cord with particle sizes less than 10 - 20 mm, supplied in an amount of 7.5 - 10.0 wt.% From the initial shale.

 Rubber additives with a particle size of 25 - 40 mm, supplied in an amount of up to 20 wt.% From the initial shale, are also used as organic additives.

 As organic waste, use soil or sand contaminated with up to 40 wt.% Hydrocarbon compounds, such as sulfur fuel oil, supplied in an amount of up to 40 wt.% From the initial shale.

Since the ash of oil shale contains oxides of alkali and alkaline earth metals, for example calcium oxides, in this process the ash acts not only as a solid heat carrier, but also as a neutralizer of compounds that are acidic during pyrolysis, in particular sulfur or hydrogen sulfide oxides etc. Under thermal processing conditions, these compounds with free oxides of alkaline and alkaline earth elements to form compounds (for example, CaSO ₄ ), which are removed with ash (chemical scavenger).

 The interval of the addition of crushed tires 7 - 10 wt.%, Determined by the duration of the continuous run without cleaning the units. When the content of the additive is 7.5 - 10 wt.%, The process proceeds in the normal mode, without changing the schedule, with the content of the additive> 10%, stops are necessary to extract the remains of the metal cord settling in some places of the installation.

 The implementation of the method allows to obtain additional quantities of hydrocarbon products adequate to the amount of additional pyrolyzable organic additives, to help protect the environment by eliminating the incineration or burial of organic waste, as well as reducing unwanted emissions.

 Examples of the method.

Example 1. To shale in the amount of 5000 tons with characteristics, weight .: W ^r = 10-12%; ^Ar = 41.5%; (CO ₂ ) ^r = 20.0; S ^r = 2.0%; O ^r = 25.5%; Q ≈ 2000 kcal / kg, add 500 tons of worn tires with metal cord, crushed to particle sizes <15 mm.

The resulting mixture is dried at 130 ^o and subjected to pyrolysis at a temperature of 470 - 480 ^o , resulting in a vapor-gas mixture (ASG), which is purified and condensed, and the semi-coke is fed to the afterburning in the technological furnace.

The ash, formed as a result of burning at 780 - 800 ^o C in the technological furnace, contains free calcium oxide, which binds the sulfur released during the pyrolysis of tire tires into sulfates (sulfite) or sulfide, which transform into ash.

 The resulting ASG is sent to the condensation unit for fractionation.

As a result, 2 wt.% More total oil (resin) was obtained compared to working without additives and 5% vol. more coke gas. The quality of shale oil has improved (sulfur content 0.6%) for boiling (light) with T = 250 ^o , because their yield in total oil increased by 15%. The amount of solid components: ash, sulfur oxides in flue exhaust gases did not increase and was below the maximum permissible concentrations.

Example 2. To shale in an amount of 4000 tons with the characteristics mentioned in example 1, add 800 tons of rubber waste (PTO waste shoe industry), crushed to a particle size of 40 mm The resulting mixture is pyrolyzed at a temperature of 470 - 480 ^o C, a vapor-gas mixture is obtained, which is cleaned of dust and condensed, and the semi-coke and ash are fed to the afterburner in a process furnace. The ash resulting from the burning of the organic part of the coke-ash residue at 780 - 800 ^o C contains free calcium oxide, which binds the sulfur compounds released as a result of pyrolysis into sulfates (sulfites), which are converted to ash. As a result, 4% more total oil was obtained compared to working without the addition of PTO and 6% vol. More semi-coke gas (sulfur content - 0.6%). The number of low-boiling (with T = 250 ^o C) in the total oil increased by 20%, the number of harmful components in the collection gases decreased by half.

Example 3. To shale in an amount of 750 tons with characteristics, as in examples 1, 2, add 300 tons of a mixture of sand and soil, impregnated with crude oil (up to 40 wt.%). After drying to 130 ^{° C.} , the resulting mixture is mixed with ash (solid heat carrier) having a temperature of 780 ^{° C.} and subjected to pyrolysis at 480 ^° C. The resulting vapor-gas mixture is sent for condensation, and the ash is sent to an ash dump.

 As a result, the yield of liquid products increased by 5 wt.% (Sulfur content 0.5%) and the yield of semi-coking gas increased by 4 vol.%.

Claims (4)

1. The method of thermal utilization of solid organic waste containing sulfur, including grinding the waste, adding it to solid fuels, heating the waste together with solid fuel without air to obtain a vapor-gas mixture and a solid carbon residue, purification and condensation of a vapor-gas mixture to obtain valuable liquid and gaseous products, characterized in that as a solid fuel use fine-grained oil shale, heating of the shale with waste is carried out to 470 - 500 ^o C, and solid carbonaceous residue to burn with the formation of ash, returned to the stage of heating as a solid coolant and chemical absorber.  2. The method according to claim 1, characterized in that used organic tires reinforced with cord, with a particle size of less than 10 to 20 mm, supplied in an amount of 7.5 to 10.0 wt.% From as organic waste containing sulfur source slate.  3. The method according to claim 1, characterized in that as an organic waste containing sulfur, use rubber waste with a particle size of 25 to 40 mm, supplied in an amount up to 20 wt.% From the initial shale.  4. The method according to claim 1, characterized in that as organic waste containing sulfur, use soil or sand contaminated with up to 40 wt.% Hydrocarbon compounds supplied in an amount of up to 40 wt.% From the initial shale.