DE4125522C1 - Simultaneous disposal of solid and liq. waste material, avoiding environmental pollution - by combustion in solid bed pressure gasification plant, quenching hot effluent gases then mixing with oxygen@-contg. gases and combusting further - Google Patents

Abstract

Process comprises combustion in a solid bed pressure gasification plant, in which the solid waste materials (contg. 1-70 wt.% sulphur cpds., hydrocarbons, halogenated hydrocarbons, dioxines, heavy metals, etc.) are combusted at temps. above 1200 C; the hot effluent gases (still contg. toxic contaminants) are quenched to temps. below 200 C, then mixed with gases contg. oxygen and combusted further in a solid bed or continuous flow reactor with waste liquid fuels (opt. contg. toxic components but having a calorific value more than 20,000 kJ/kg, mixed with 3-35 wt.% toxic solid waste contg. at least 10 wt.% mineral components) at temps. above 1200 C, with a residence time in the reactor at least 2 s. The effluent gases are washed with aq. carbon suspensions to remove residual contaminants; and the slag is tapped off for building and road constructions. USE - The process allows poor quality coals contg. sulphur, minerals and much ash, etc., to be utilised in the combustions, and avoids environmental pollution.

Description

The invention relates to the field of gasification and in particular to Fixed bed pressure gasification, oil pressure gasification and entrained flow gasification as well as on the Field of waste disposal.

Fixed bed pressure gasification is carried out with the different feedstocks such as raw lignite, Lignite briquettes, hard lignite and hard coal operated. The quality of these feedstocks ash and water content can vary widely. The Processing effort for the gasification material is low.

The U. a. described in W. Peters "coal gasification", Verlag Glückauf GmbH, Essen The basic principle of fixed bed pressure gasification has been further developed in many modifications. Further developments according to DE-PS 26 40 180 and 27 32 544 are known, in which one Combination with the fluidized bed has been proposed. In other solutions, so u. a. in the DD-PS 38 791, 1 10 297, 1 19 814, 1 21 796, 1 32 980, 1 33 818 and DE-PS 27 05 558 become paths and Possibilities to increase performance, to remove liquid slag, to lower the Dust content in the raw gas and to avoid slagging in the fixed-bed pressure gasifier suggested.

The basic disadvantage of all previously practiced solutions is that in the raw gas Dust, higher and lower boiling hydrocarbons and water-soluble organic Compounds such as alcohols and aromatics and their derivatives are included, and expensive Ancillary systems for the extraction and recycling of individual products and for the avoidance of Environmental hazards are required.

According to DD-PS 2 59 875 a proposal has become known, according to which to avoid Waste products the fuel bed height in the fixed bed pressure carburetor is extremely reduced and due to the temperatures in the gas space of approx tars, oils and dust particles contained in the gas space are to be converted into raw gas. This method cannot be mastered from a safety point of view because of the extremely low level Fixed bed oxygen breakthroughs are provoked in downstream equipment too Gas explosions can lead.

Also known is a proposal according to DD-PS 43 253, in which the liquid contained in the gas and solid components when leaving the gas generator auto-oxidatively with the addition of Gasifying agents are to be converted into gas. This process is not economical makes sense because part of the gas generated is burned. A sure defined turnover of Liquid and solid components are not guaranteed when this procedure is carried out. There the proposal still does not contain any safe reworkable teaching is the one presented Process with gas explosions to be expected.  

In DD-PS 1 50 475 a solution is shown, after using a hydrogenation catalyst in the case of post-gasification of fixed-bed pressure gasification raw gas by higher hydrocarbons Hydrocracking should be implemented. This method has the disadvantage that the Inlet temperature of the raw gas in the post-gasifier to the working temperature of the catalyst must be set. This is only possible when using lignite in the gasification process complicated control and process technology can be implemented. Another disadvantage of the process is the rapid contamination of the catalyst with coal dust and ash particles, which with be carried with the raw gas and the resulting high operating costs. Farther proposals are shown in DE-OS 25 32 197 and 25 32 198 for the gasification of Hydrocarbons from fixed bed pressure gasification raw gas this with the addition of oxygen in a post-gasifier, which contains a fixed bed of inert or catalyst material, initiate, resulting in gasification and cracking reactions due to temperature increases should occur.

This method is disadvantageous in that it controls the raw gas composition and the amount of raw gas in the post-gasifier is not possible and the fixed bed in Post-carburetor due to contamination due to dust and ash input to reduce performance or can lead to the shutdown of the gasification process.

Special waste includes waste from commercial and other companies and public institutions that are of a special nature, type or quantity are hazardous to health, air or water.

Special waste is generated in the chemical industry, in the metalworking industry Industry as well as energy and waste management.

In the chemical industry fall mainly sulfur, hydrocarbon as well halogenated waste.

Oil emulsions and paint sludges come from the metalworking industry and electroplating waste.

In thermal waste recycling plants such as incineration and pyrolysis, some fall contaminated residues and in the area of heat and gas cleaning aircraft and Filter dust, the disposal of which poses great problems.

In particular, the contamination of these dusts with organic pollutants such as dioxins and Furans and heavy metals impose high environmental requirements in the case of landfill.

Solutions are currently being proposed for this and similar hazardous waste Integration in clayey materials DE-PS 39 18 259, DE-PS 37 13 482, DE-PS 39 19 011 or according to DE-PS 35 02 215 residues containing heavy metals to solid landfill products process, which then sometimes with a very high cost in underground landfills be deposited.  

Alternative solutions provide melting solutions. Such solutions are in DE-PS 39 39 344, DE-PS 32 06 984 described. These systems require a very high one Energy expenditure. You are currently mainly in the laboratory and laboratory stage Pilot plants and still require considerable development to be put into practice and expenditure of time.

A proposal from DD-PS 2 67 880 is known from gasification technology, according to which ash-containing liquid fuel separately and independent of a burner that is equipped with a Dusty fuel is supplied with the water vapor via a feed line Reaction space is supplied and the oxygen required for the autothermal partial oxidation of the ash-containing liquid fuel via the coal dust burner to the gasification reactor is fed.

The gasification of liquid residues requires a great deal of effort using this method of coal dust, the use of which leads to high gas production costs. The amount used The quantity of liquid residues in this process is very limited.

The object of the invention is to dispose of liquid and solid waste to dispose of the gasification process in an economical and environmentally relevant manner.

According to the invention, the object of the invention is achieved in that Fixed bed pressure gasifier 1-70% of the gasification substance as solid waste material, which is sulfur and / or contains hydrocarbons and / or PCB and / or dioxin and / or heavy metals, is used. These solid waste materials such as loaded activated coke, contaminated Soil, scrap of scrap tires, light shredder, oil-soiled textile waste or plastic waste can either be integrated into the carbon matrix by briquetting or in a mixture with Charcoal can be introduced into the fixed bed pressure gasifier. Contained heavy metals mainly integrated into the slag that is used as a building material or can be deposited. The resulting pollutant and dust Fixed-bed pressure gasification crude gas is in a downstream gasifier, which as entrained flow gasifier with a reactor inner wall as a cooled pipe screen and with liquid slag run is carried out, together with liquid waste, which one Have a calorific value of greater than 20,000 kJ / kg and hydrocarbons and / or sulfur and / or PCB and heavy metals and / or dioxin and which additionally 3-35% Introduced waste materials as solid components.

The total amount of gas in carrying out the process is both about the amount of Fixed bed pressure gasification raw gas as well as the amount of liquid waste set.  

The solid waste is characterized by the fact that it contains more than 10% mineral Ingredients and sulfur and / or heavy metals and / or PCB and / or dioxin and / or Contain hydrocarbons. The grain size of the solid waste is at the implementation of the method preferably <0.5 mm.

The procedure in the entrained-flow gasifier is carried out at a reaction temperature, the above 50 ° C of the melting temperature of the mineral components of the solid waste and is set to at least <1200 ° C. The residence time of the resulting gas at the set reaction temperature is 2 seconds before the shock-like cooling of the resulting slag-containing gases is caused to <200 ° C.

When using the method, the input materials can be used for simultaneous disposal from liquid and solid waste materials in entrained-flow gasifiers, for example Contaminated waste oils in a mixture with paint sludge, sewage sludge or flight and Assemble filter dust from exhaust gas cleaning systems.

It is also possible to use only solid residues from the Coal processing and petroleum industry.

According to the invention, the post-carburetor can be used to carry out the method Fixed bed pressure gasification raw gas or for the disposal of liquid waste.

When carrying out the process, this becomes the quenching of the hot reaction gases soot water is freed of <99% of its constituents and mixed with it liquid waste materials introduced into the entrained-flow gasifier.

When carrying out the overall process, gas cooling in the liquid phase accumulating residual components of pollutants by known methods from the separated aqueous phase and in a known manner the fixed bed / entrained flow gasification fed. Likewise, the pollutant components present in traces, in particular Heavy metals, washed out of the raw gas using a low-temperature wash and that Detergent partly in the after enrichment of the pollutant components Gasification reactors returned.

The advantage of the method is in particular that liquid and solid at the same time Waste materials can be disposed of and that with the heat of reaction that occurs during disposal of the liquid waste in the entrained-flow gasifier, the solid waste contained in the Dispose of the mixture with the heavy metal residues from the soot water treatment are and both the heavy metals of the liquid waste materials and that of Soot water in the mineral constituents of the solid waste materials non-elutable will.  

Another advantage of the overall process is that the combined disposal of the solid and liquid waste in the gasification processes is very environmentally relevant and thereby at the same time due to the higher efficiencies in energy use Conservation of resources helps. The inclusion of pollutants at the Gas and wastewater treatment occur in the gasification and melting process of the waste materials leads to a new type of complex disposal solution for solid and liquid waste.

An embodiment of the invention is shown in the drawing and is in the following described in more detail.

In a fixed bed pressure gasifier 1 , which is operated under a pressure of 25 bar, hourly

13.7 t lignite briquettes 2 (water content 18.5%, tar content 8%, ash content 8%)
3.1 t of contaminated soil 3 with a hydrocarbon content of 5%
1.7 t old tires 3
1.7 t shredded light goods 3

smuggled in. The rotary grate 4 are a mixture 5 2500 m³ i. N. oxygen / h and 16.4 t gasification vapor / h introduced into the reactor. An inert ash / slag mixture 6 in a total amount of 4 t / h is applied via the rotating grate 4 , which mixture can be used as a building aggregate or filler or can be deposited safely. In the fixed-bed pressure gasifier, the hydrocarbons contained in the contaminated soil are distilled off, split up or gasified. 40-70% of used tire and shredder light goods are converted into gas components and 20 to 50% into hydrocarbons. 3-12% go into the ash / slag fraction depending on the composition. The remaining components are discharged as ash / slag mixture via the rotating grate.

Via the Rohgassammelraum 7 20,700 m³ i. N. dry raw gas and 13 800 m³ iN water vapor / h with a temperature of approx. 450 ° C via the raw gas manifold 8 via the burner 10 into the post-gasifier 9 , designed as entrained-flow gasifier with forced-cooled reaction chamber contour and liquid slag discharge and conducted with an operating pressure of 24 bar.

This waste oil / waste material mixture is pumped around via the circulation system 24 and the pump 25 in order to avoid signs of settling. Via the branch line 26 and the metering pump 27 , 12 t / h of the waste oil / waste mixture via the burner 28 in a gasification reactor 31 , which is operated at a pressure of 25 bar, has a volume of 30 m 3 and the reaction chamber contour 32 of which is forced-cooled, fed.

The supplied high pressure steam 30 in an amount of 4 t / h serves both to swirl the waste oil and waste mixture and as a gasifying agent. Using the amount of oxygen 29 of 10,000 m³ i. N./h the autothermal partial oxidation of the waste oil 23 and the organic components of the solid waste materials 22 takes place . The melting point of the mineral components of the solid waste materials is 1250 ° C.

The gas reaction temperature is set at 1400 ° C using the flame reaction. In the Gasification reaction results in 40,000 m³ i. N. raw gas / h. The mean residence time in Gasification reactor is 2.7 sec.

The quenching 22 of the raw gas, which transports the slag formed in liquid form, cools the raw gas to 200 ° C. and granulates the slag 30 , which is discharged from the quench container 23 via the water bath 24 .

The cooled raw gas 25 contains no detectable amounts of dioxins and is used as a fuel gas for electricity generation after a low-temperature wash.

The heavy metal-containing soot pellets 29 obtained in the soot water treatment 27 working according to the pellet process are conveyed to a tank system 21 in a total amount of 400 kg / h.

At the same time, heavy metal and salt sludge 17 from the wastewater treatment and low-temperature gas scrubbing 39 are conveyed once a day into the tank system 21 in a total amount of 1000 kg and mixed into the gasification mixture for use in the entrained-flow gasifier.

The heavy metal components of the waste materials are melted into the slag so that they cannot be eluted. The slag can be used as a building material or deposited safely. The soot water 26 accumulating in the quench tank 23 is free of tar, oil, phenol and PCB and is sent to the soot water treatment unit 27 . The heavy metal components of the waste materials are melted into the slag so that they cannot be eluted. The slag can be used as a building material or deposited safely.

The soot water 26 accumulating in the quench tank 23 is free of tar, oil, phenol and PCB and is sent to the soot water treatment unit 27 . The waste water 28 running out of the soot water treatment 18 is fed to a desalination plant.

The dry crude gas introduced has the following composition:

CO₂ -33.5%
CO -15.0%
H₂ -36.0%
CH₄ -12.5%
N₂ -0.9%
O₂ -0.1%
C₁-C₄ -2.0%

The raw gas also contains approx. 90 g cyclic and aliphatic hydrocarbons / m³ i. N. and 10 g dust / m³ i. N. which contains about 20% ash components.

Via the burner 10 , 12 t of waste oil / waste mixture 11 from the tank system 21 are simultaneously introduced into the post-gasifier.

Waste oil 23 with a calorific value of 33,000 kJ / kg and with the following pollutant concentrations are placed in the tank system 21 :

PCB -200 mg / kg
Ni -2000 mg / kg
Pb -2000 mg / kg
Zn -2500 mg / kg
S -4%

with 0.1 kg sewage sludge dried to 15% water content 22 / kg waste oil, the 10% mineral Contains components and the following pollutant components:

Pb: 1000 mg / kg
Cu: 500 mg / kg
Zn: 2000 mg / kg

as well as with 0.15 kg filter dust 22 from the cleaning stage of waste incineration gases / kg waste oil, which contains 60% mineral components and the following pollutant components:

200 mg PCDD and PCDF / g
6000 mg Pb / kg
24000 mg Zn / kg
1000 mg Cu / kg
1700 mg Sn / kg
1400 mg Cr / kg

mixed.

List of the reference symbols used

1 fixed bed pressure carburetor
2 coal
3 solid disposal products (contaminated soil, scrap tire, shredder light goods)
4 rotating grate
5 gasifying agents
6 ash / slag
7 Raw gas collection room
8 raw gas exhaust pipe
9 gasification reactor with cooled reaction chamber contour
10 burners
11 Liquid disposal products (waste oil)
12 oxygen
13 steam
14 tank system
15 solid waste
16 waste oil
17 Heavy metal and salt sludge from wastewater treatment and low-temperature gas scrubbing
18 circulatory system
19 circulation pump
20 branch line
21 dosing pump
22 quench water
23 quench containers
24 water bath
25 raw gas
26 soot water
27 Soot water treatment
28 waste water
29 soot pellets
30 slag granules

Claims (3)

1. Process for the combined disposal of solid and liquid waste materials in the gasification process in the case of fixed-bed pressure gasification and a secondary gasifier connected downstream of the fixed-bed pressure gasifier on the raw gas side, designed as entrained flow gasifier, with execution of the inner wall of the reactor as a cooled pipe screen, with liquid slag discharge and shock-like cooling of the resulting slag-containing gases to <200 ° C, characterized in that 1-70% of the gasification substance is used as a solid waste material which contains sulfur and / or hydrocarbons and / or PCB and / or dioxin and / or heavy metals in the fixed-bed pressure gasifier and that the resulting fixed-bed pressure gasification raw gas containing pollutants and dust in a post-gasifier together with a liquid waste material that has a calorific value of more than 20,000 kJ / kg and contains hydrocarbons and / or sulfur and / or PCB and heavy metals and / or dioxin, and additionally 3-35% waste material as F Estonia constituents with proportions greater than 10% of mineral constituents and sulfur and / or heavy metals and / or PCB and / or dioxins and furans and / or hydrocarbons, at a reaction temperature that is above 50 ° C the melting temperature of the mineral constituents of the solid waste materials and is set to <1200 ° C, gasified, the residence time of the resulting gas at the reaction temperature of <1200 ° C in the gasification reactor is <2 sec and that the soot water obtained during the quenching of <99% of its heavy metal-containing soot components using known methods is freed and mixed with pollutant sludges that occur during wastewater treatment of the wastewater generated in the process and / or during gas cleaning of the raw gas generated, are returned to the fixed bed or entrained flow gasifier. 2. The method according to claim 1, characterized in that when carrying out the Process of the post-gasifier with fixed-bed pressure gasification raw gas or for the disposal of liquid and solid waste can be operated. 3. The method according to claim 1, characterized in that when carrying out the Procedure of entrained-flow gasifier can be operated separately.