DE4226034C1 - Combined process for the gasification of solid, pasty and liquid residues and / or waste materials - Google Patents

Description

Historically, the least expensive method to remove solid waste is deposited in open landfills or underground. However, landfills for unprocessed waste pose serious problems. Leaching easily leads to groundwater pollution. Valuable floor space get lost. Fires can occur.

A cheaper method that reduces these problems is a sanitary one Ground filling by composting and covering the waste with earth.

Regardless of this, in larger urban areas this procedure was carried out in increasingly unattractive because suitable places are less and less available stand. Both of the above methods were preceded by incineration of the waste the area filling. Conventional waste incineration ensures that substantial reduction in volume of waste materials and reduced by leaching pollution caused, but brings new environmental problems, such as one Air pollution and increased amounts of contaminated residues such as filter dust and Salt mud, with itself. Although volume reductions of 80 to 90% are possible, the residue or the ash is not biologically inactive in every case, so that still a terrain filling is necessary. Furthermore, the conventional one Combustion the recovery of utility values is generally minimal.

The Anderson process (US PS 37 29 298). Waste is in the upper part and oxygen in the lower part of an upright shaft furnace. During execution In the process, shredded waste is used without being compacted. The one in the lower part the resulting liquid slag is tapped continuously. Had this procedure the disadvantage that the shredded waste compacted in the reactor and closed Channel flows with the known disadvantages of derating and Risk of explosion.

According to DE-OS 26 19 302 it has been proposed to use waste materials in the form of defined pellets to gasify from shredded waste in the shaft furnace. This procedure is restricted to gasification of defined pellets under normal pressure Liquid slag discharge applicable.

DE-AS 23 23 654 describes a process in which solid waste materials Household garbage in the top and liquid hydrocarbonaceous condensates from the Gas cleaning and liquid waste are introduced into the lower part of the reactor become. This method has the disadvantage that a targeted fixation or Organic and inorganic pollutants were not eliminated. In the proposed cooling of the gas to 300 ° C is a Denovo synthesis of Dioxin and furans are not excluded.

According to a proposal according to DE-OS 33 42 383 in a combined entrained flow and fixed bed pressure carburetors in a primary process a suspension and in one Gasified lumpy gasification secondary process, the resulting slag in a sodium carbonate melt bath is collected.

This process serves to react heavy metals, especially vanadium to avoid with the lining.

This method has the disadvantage that the use of solid and liquid Waste materials are subject to narrow limits and that in particular a hydrocarbon and / or dioxin destruction in the secondary reactor can only be achieved incompletely.

The object of the invention is liquid, pasty and solid residual and / or Waste materials that are contaminated with inorganic and / or organic pollutants, to use the process of pressure gasification economically and environmentally friendly.

According to the invention, this object is achieved by that 1-80% solid or 1-60% solid and / or 1-20% pasty carbonaceous with organic and / or inorganic pollutants contaminated residues and / or waste materials in fixed-bed pressure gasifiers converted to useful gas be, the heating time of the residual and / or waste materials in a reducing Atmosphere to <350 ° C and <400 ° C and the dwell time of the remaining and / or Waste materials in the fixed bed pressure gasifier up to direct contact with the generated one Raw gas flow, which has a temperature of <350 ° C and which after leaving the Fixed bed pressure gasifier is cooled to <200 ° C, is greater than 1 h, and that the resulting from the raw gas cooling to <25% water content Condensates without / or together with liquid carbon-containing residues and waste materials, which are contaminated with organic and / or inorganic pollutants, in Entrained-flow gasifier can be converted to useful gas, the gas and Soot, heavy metal and saline residues from water treatment stages in particular the entrained-flow gasification is returned to the fixed-bed pressure gasifier and the fine-grained ash components of the fixed-bed gasifier, in their Eluate heavy metals can be detectable with the liquid residues be mashed and in a proportion of 1-30% in the feed of the Entrained flow gasifier a slagging of the fine-grained ash components of the Fixed bed pressure gasifier with additional incorporation of heavy metal components liquid residues and / or waste materials is effected.

The solid and / or pasty residues and / or waste materials can be contaminated, for example Soil, plastic waste, wood, rubber products, solid waste containing oil, Drug residues, tar residues, color sludge, sewage sludge in fine-grained, coarse, pasty or agglomerated form and can be, for example with aliphatic, aromatic or chlorinated hydrocarbons, polychlorinated Biphenyls, dioxins, furans, sulfur compounds and heavy metals his.

In the fixed bed pressure gasifier, volatile organic substances are separated Compounds that are used in the cooling of the raw gas in the closed system Hydrocarbon fractions occur.

PCB’s, dioxins and furans are heated in the fixed-bed gasifier reducing atmosphere to <1200 ° C completely destroyed.

If small proportions are discharged with the raw gas, these substances are released their oily properties and oil solubility in those separated in the condensation liquid hydrocarbons.

These are without or together with liquid residues and / or waste materials with organic pollutants are contaminated in the entrained flow gasifier at <1300 ° C and one Dwell time of <3 s converted to useful gas, which after leaving the Entrained flow gasifier is suddenly cooled to <200 ° C.

The liquid, pumpable, residual or waste materials can, for example, waste oil, solvents, Paint and color sludge and dye suspensions, the analog Pollutant groups such as the above contain.

In the lower part of the fixed-bed pressure gasifier, targeted granulation takes place at <1200 ° C the resulting ash into non-elutable fusible bandages, in which the in the feed contained heavy metals are primarily included.

Eliminable fine-grained ash components become the liquid residues and / or waste materials mixed in a proportion of 1-30% and in the entrained flow gasifier at <1300 ° C glazed. At the same time, the non-volatile heavy metals of the liquid feedstocks.

Volatile heavy metals enter the water phase and are primarily classified as Sulphide, hydroxide, oxides and carbonates deposited.

This proportion is used in the soot water treatment as well as in the subsequent biological Process water treatment with the resulting organic sludge endured and returned to the fixed bed pressure gasification for inclusion in the slag.

In the overall process, the sulfur components are known from the Endured gas flow and recovered as a resource.  

With the proposed method, a complex environmentally friendly recycling of solid, pasty and liquid residues and / or waste materials guaranteed become. The synergy and combination effects result in an almost residue-free recycling with high efficiency of material conversion. The cracked gas generated can can be transported or stored as an energy source or allows direct Conversion into chemical raw materials.

An embodiment is shown in the drawing and is described in more detail below described.

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

10 t lignite briquettes 2 ,
3 t of contaminated soil 3 with a hydrocarbon content of 5%, a dioxin load of 2000 ng / kg and 800 mg chromium / kg, 800 mg lead / kg, 600 mg Cu / kg,
3 t plastic waste 3 ,
3 t of oil-contaminated wood 3 ,
0.5 t residues from process water treatment 34

smuggled in. About 2400 m³ iN oxygen / h and 15.6 t gasification vapor / h are introduced into the fixed-bed pressure gasifier 1 as a mixture 5 via the rotating grate 4 . An ash / slag mixture 6 is fed to a classifying device of known type via the rotating grate 4 .

If fine-grained elutable ash 25 is produced , it can be separated off and fed to a mixing device 24 for slagging in the entrained-flow gasifier. The resulting slag granulate 36 of the fixed bed pressure and entrained flow gasifier can be used as backfill material or as construction aggregate.

In the fixed-bed pressure gasifier, the hydrocarbons contained in the contaminated soil and in the waste wood are distilled off, split up and partially converted into useful gas. The dioxin contained in the contaminated soil is destroyed in the fixed bed pressure gasifier in a reducing atmosphere at 300-800 ° C. If small amounts get into the hydrocarbon fraction of the condensates 17 , the final conversion takes place in the entrained-flow gasifier 23 .

The plastic wastes 3 contained in the gasification mixture of the fixed bed pressure gasifier are converted to 50-70% in gas components and 20-50% to hydrocarbons. 2-5% go to the ash / slag fraction 6 .

The hydrocarbon portions of the waste wood 3 used and that of the contaminated soil used are distilled off, split up or converted into gas. The waste wood 3 itself is gasified, the remaining constituents of the earth with heavy metal components become a non-elutable component of the ash / slag fraction 6 .

The organic constituents of the residues from the process water treatment 3 are converted to useful gas, the inorganic constituents are melted into the ash / slag mixture 6 .

Via the Rohgassammelraum 7 19,700 m³ into dry crude gas / h with a content of oil and tar constituents of 80 g / m³ iN and 0.7 kg of steam / m i. N passed through the raw gas outlet 8 into the washing cooler 9 . Here the 420 ° C hot raw gas is cooled to 195 ° C with 20 m³ quench water / h. The quenched raw gas 11 is indirectly cooled to ambient temperature in the downstream coolers 12 by means of cooling water 13 . The cooled raw gas 14 arrives at conventional gas cleaning plants and is then used for material or energy purposes.

The resulting condensates 15 are separated in a process water treatment stage 16 into a process water fraction 31 and a hydrocarbon fraction 17 .

The approximately 1.58 t hydrocarbons 17 are a pump 18, together with 12 t of waste oil 19, which in a mixing device 24 with 1.3 t fine ash / h from the solid bed pressure gasification 25 and additionally mixed with 10 500 m³ in oxygen / h 20 and 6.8 t of high pressure steam / h 21 via the burner 22 in the entrained flow gasifier 23 to 25 bar and 1350 ° C. fission gas.

The amount of cracked gas 26 from 45,000 m³ iN / h is cooled to 195 ° C. with 60 t / h of quench water 27 , the cooled cracked gas 29 being fed from the quench chamber via cooling and cleaning stages for material or energy recovery. The resulting slag granulate 36 contains non-elutable heavy metal components of the ash used and the used oil used and can be used in the construction industry. The resulting soot water 30 is introduced together with the process water 31 into a process and soot water treatment 32 , which consists of various process stages such as de-phenolization, soot filtration and a biological purification stage. The soot and bio-sludge residue 34 is fed back into the fixed-bed pressure gasifier 1 , and the cleaned process water can be reused or discharged into a receiving water.

List of the reference symbols used

1 fixed bed pressure carburetor
2 lignite briquettes
3 Solid waste and residues
4 rotating grate
5 gasifying agent mixture
6 ash / slag mixture
7 Raw gas collection room
8 raw gas outlet
9 washer coolers
10 wash water
11 quenched raw gas
12 coolers
13 cooling medium
14 cooled raw gas
15 gas condensate
16 Process water treatment
17 hydrocarbon fraction
18 centrifugal pump
19 waste oil
20 oxygen
21 steam
22 burners
23 entrained flow carburettors
24 mixing device
25 fine-grained ashes
26 fission gas
27 quench water
28 quench chamber
29 cooled cracked gas
30 soot water
31 process water
32 Process water and soot water treatment
33 treated wastewater
34 solid or pasty residue
35 classifier
36 slag granules

Claims (1)

Combined process for the gasification of solid, pasty and liquid residues and / or waste materials, with parallel gasification in the fixed bed pressure gasifier, and in the entrained flow gasifier, characterized in that 1-80% solid or 1-60% solid and / or 1-20% pasty Carbon-containing residues and / or waste contaminated with organic and / or inorganic pollutants are converted into useful gas in fixed-bed pressure gasifiers, with the heating-up time of the residues and / or waste materials in a reducing atmosphere to <350 ° C and <400 ° C and the residence time of the rest - And / or waste materials in the fixed-bed pressure gasifier until direct contact with the raw gas stream generated, which has a temperature of <350 ° C and which is suddenly cooled to <200 ° C after leaving the fixed-bed pressure gasifier, is greater than 1 h and that in the raw gas cooling accumulating condensates dewatered to <25% water content without / or together with liquid carbon-containing residues and waste materials, w elche are contaminated with organic and / or inorganic pollutants, are converted into entrained-flow gasifier to useful gas, the soot, heavy metal and salt-containing residues occurring in the gas and water treatment stages, in particular the entrained-flow gasification, being returned to the fixed-bed pressure gasifier and the fine-grained ash components of the fixed-bed pressure gasifier, in the eluate of which heavy metals can be detected, mashed with the liquid residues and in a proportion of 1-30% in the feed product of the entrained flow gasifier, slagging of the fine-grained ash constituents of the fixed-bed pressure gasifier with additional incorporation of heavy metal parts of the liquid residues and / or waste materials is brought about.