JPH0470959B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to the partial oxidation of liquid hydrocarbon fuels comprising an oxygen-containing hydrocarbon fuel and a slurry of solid carbon fuel, and more particularly to the Concerning a pollution abatement method for the environmentally safe disposal of toxic inorganic cyanide-containing sludge produced during the treatment of water used for cooling or cleaning hot effluent gas streams from generators It is something.

[Background of the invention]

The hot syngas stream (i.e., H ₂ + CO gas mixture) exiting the free-stream noncatalytic partially oxidized gas generator contains trace amounts of HCN, i.e., 0.5 to 100 PPM (by weight), as well as soot, ash, slag, and This includes entrapped particulate matter such as pieces of refractory material. Water is most commonly used to cool or scrub the hot effluent gas stream from the reaction zone to remove entrapped materials.
A portion of the HCN in the syngas stream, along with trace amounts of other water-soluble impurities in the gas stream such as formates and halides, is absorbed by water in the digestion or cooling zone.

Since large amounts of water are used in the production of synthesis gas, reducing gas or fuel gas by partial oxidation of liquid hydrocarbon fuels, including oxygenated hydrocarbon fuels and slurries of solid carbon fuels, it is desirable to regenerate cooling water or wash water. , the water can be recycled to the gas cooling area or gas cleaning area for reuse.
This is especially important in arid regions. actually,
For both economic and environmental reasons, water recovery, purification and recycling of purified water has become necessary.

US Pat. No. 4,211,646 discloses a method for treating wastewater which is toxic and corrosive due to the presence of cyanide, formate and halides. Toxic inorganic sludge and purified wastewater streams are obtained by the method. However, the US patent does not disclose a method for safely disposing of the concentrated toxic inorganic sludge.

In plants that produce synthetic gas from oil and coal, sludge disposal requires high operating costs. In order to make the disposal of the sludge environmentally acceptable, the free cyanide and cyanide complexes in the sludge must be destroyed. Cyanide complexes are resistant to chemical destruction. Although sunlight can destroy cyanide complexes, free cyanide is not destroyed by sunlight. If inorganic sludge is dumped underground, there is a risk of groundwater contamination.

[Summary of the invention]

These and other problems are reduced by the process of the present invention in which substantially all free cyanide and cyanide complexes in the mineral sludge are destroyed in the reaction zone of the partial oxidation gas generator.

In this pollution reduction method, a liquid hydrocarbon fuel obtained by partial oxidation comprising a slurry of hydrocarbon organic matter and a solid carbon fuel treated with oxygen is used.
A hot raw effluent syngas stream consisting of H ₂ and CO and containing toxic gaseous impurities such as H ₂ S and COS and trace amounts of HCN and HCL is cooled with water or
Wash it. After the remaining syngas is separated, small amounts of these toxic substances remain in the water. formic acid and
NH ₃ may also be present in cooling water and cleaning water. At a temperature in the range of about 15.6 to 98.9 °C (about 60 to 210 °C) and a pH of about 7 to 9, at least a portion of the cooling water or wash water is mixed with ferrous sulfate or ferrous chloride; Toxic inorganic cyanide-containing sludge is generated by adding sodium hydroxide or calcium hydroxide to the treated water to adjust the pH to a value of about 9-11 and precipitating the inorganic cyanide-containing sludge. do. To inhibit the formation of calcium sulfide, preferred combinations of ferrous salts and bases are (a) ferrous sulfate and sodium hydroxide; (b) ferrous chloride and calcium hydroxide. . After separating the toxic cyanide-containing sludge from the water, it is mixed with liquid hydrocarbon fuel and the mixture is heated to about 927-1649°C (about 1700-1700°C
3000〓) and a pressure in the range of about 1 to 250 atmospheres, for example by reacting by partial oxidation in a gas generator at about 10 to 200 atmospheres.
Can be safely disposed of without causing environmental problems. The water separated from the sludge is removed by steam to remove ammonia, adjust the pH to a value of 6-8 and remove organic substances such as formate in a conventional biological reactor. Biological residues are formed which are recycled to the gas generator as part of the feed. Purified water can be recycled to the digestion cooling area and wash area. Alternatively, purified water and biological residues can be released from the system without contaminating the environment.

〔Example〕

The present invention provides a method for producing syngas, fuel gas, or reducing gas streams from a liquid hydrocarbon fuel comprising an oxygen-containing hydrocarbon fuel and a slurry of solid carbon fuel in a liquid carrier. It relates to an environmentally safe continuous method for disposing of hazardous materials. The feedstock charged to the gas generator also includes toxic inorganic cyanide-containing sludge generated downstream of the process. Depending on the composition of the liquid hydrocarbon fuel feedstock, the produced gas can be used as is, after further treatment, or after being purified by conventional methods. Furthermore,
Water contaminated with toxic substances during digestion, cooling and cleaning of hot raw gas streams can be purified for reuse or for safe disposal without contaminating the environment.

In the method of the present invention, a liquid hydrocarbon fuel comprising an oxygen-containing hydrocarbon fuel and a slurry of solid carbon fuel in a liquid carrier is partially oxidized with a free oxygen-containing gas in the presence of a temperature buffer. A flow of effluent gas is generated.

The gas generator is a vertical cylindrical pressure vessel made of steel whose inner surface is coated with a refractory material. Typical partially oxidized syngas generators are shown in commonly owned US Pat. Nos. 2,818,326 and 3,544,291. A burner is placed along the central vertical axis at the top of the gas generator to admit the feed stream. A suitable annular burner is shown in commonly owned US Pat. No. 2,928,460.

As used herein, the term liquid hydrocarbon fuels refers to petroleum distillates and residues;
Gasoline, naphtha, kerosene, crude asphalt, gas oil, residual oils, tar sands and shale oils, oils extracted from coal, aromatic hydrocarbons (benzene, toluene, xylene, etc.), coal tar, obtained from fluid catalytic cracking operations It is meant to include various materials such as circulating gas oils, furfural extracts of coker gas oils, mixtures thereof, and the like. The definition of liquid hydrocarbon fuels includes carbohydrates,
Oxygen containing cellulose materials, aldehydes, organic acids, alcohols, ketones, oxygenated fuel oils, waste fluids, and by-products from chemical processes containing oxygenated hydrocarbon organic materials, and mixtures thereof. Contains added hydrocarbon organic substances.

Also included within the definition of liquid hydrocarbon fuels are solid carbon fuel slurries that can be pumped.
Solid carbon fuel slurries that can be pumped contain between 45
Also included are solids contents ranging from about 25 to 70 wt.%, such as 68 wt.%. The slurry medium can be water, liquid hydrocarbon fuel, or both.

Solid carbon fuels include coal such as anthracite, bituminous, and subbituminous coal, coal coke, lignite, coal liquefaction residues, shale, tar sands, petroleum coke,
Includes asphalt, pitch, particulate carbon (soot), concentrated sewage sludge, and mixtures thereof. Solid carbon fuel is ASTM E11−70
Sieve Designation Standard
(SDS) Can be crushed to a particle size that passes 100% of 1.4mm alternative No. 14.

The use of temperature moderating materials to moderate the temperature within the reaction zone of a gas generator generally depends on the carbon/hydrogen ratio of the charge and the oxygen content of the oxidizer. Suitable temperature-reducing materials include steam, water,
CO-rich gas, liquid _CO2 , cooled effluent gas from gas generators, by-product nitrogen from air separation equipment used to produce nearly pure oxygen,
and mixtures thereof. The temperature moderating material can be mixed into the gas generator with either the liquid hydrocarbon fuel feedstock or the free oxygen-containing stream, or both. Alternatively, the temperature moderating material can be introduced into the reaction zone of the gas generator through a separate conduit in the fuel burner. When water is included in the gas generator as a temperature buffer or slurry medium, the weight ratio of water to hydrocarbon fuel is in the range of about 0.3 to 2.0, preferably in the range of about 0.5 to 1.0.

As used herein, the term free oxygen-containing gas refers to air, oxygen-enriched, i.e.
Air containing more than 21 mol% and almost pure oxygen, i.e. more than 95 mol% oxygen (the rest is
_N2 and rare gases). The free oxygen-containing gas is introduced into the burner at a temperature ranging from about room temperature to about 649°C (1200°C). The atomic ratio of free oxygen in the oxidizing agent to carbon in the charged material (O/C, atom/atom) is preferably in the range of about 0.7 to 1.5, such as 0.80 to 1.2.

The relative proportions of solid carbon fuel, liquid hydrocarbon fuel (if present), water or other temperature moderating material, and oxygen in the charge stream supplied to the gas generator are determined by the partial oxidation gas Most of the carbon in the fuel feed to the generator (such as 80-90wt.%, e.g. 75-95wt.%) is replaced by carbon oxides (e.g. CO,
CO ₂ ) and maintain the temperature within the autogeneous reaction zone in the range of about 927-1649°C (about 1700-3000°), such as about 1288-1593°C (about 2350-2900°C). Adjust carefully. Solid carbon slurry feeds containing ash are advantageous because the ash in the solid carbon fuel forms a molten slag at such latter reaction temperatures.
The molten slag is much more easily separated from the hot effluent gas than the fly ash. The pressure within the reaction zone is approximately 1 to 200 atmospheres, such as approximately 10 to 200 atmospheres.
It is in the range of 250 atmospheres. The time in the reaction zone of the partial oxidation gas generator is approximately 0.5 to 20 seconds and typically approximately 1.0 to 20 seconds.
It is 5 seconds.

The effluent gas stream leaving the partially oxidized gas generator has the following composition (in mole %), depending on the amount and composition of the feed stream: That is, H ₂
…8.0~60.0; CO…8.0~70.0; CO ₂ …1.0~50.0;
_H2O ...2.0~50.0; _CH4 ...0.0~2.0; _H2S ...0.0~
2.0; COS…0.0~1.0; _N2 …0.0~80.0; Ar…0.0~
It is 2.0. Trace amounts (ppm) of the following gases may also be present in the gas stream: That is,
HCN…0.5 to about 100 (for example, about 2 to 20); HC1…
0 to about 20000 (for example about 200 to 2000); NH ₃ ...0
~about 10000 (for example about 100-1000). In the effluent gas stream, about 0.5 to 20 wt.%, such as about 1 to 4 wt.%,
of particulate carbon (the basis weight of carbon in the feedstock to the gas generator) and the remainder of the unchanged ash-containing solid carbon fuel feedstock. Molten slag resulting from melting of coal ash is also included in the gas stream exiting the gas generator.

Approximately from the reaction zone of a non-catalytic partial oxidation gas generator
The effluent gas stream at a temperature of 927-1649°C (approximately 1700-3000°C) can be (1) digested, cooled and washed with water, and (2) cooled in a gas cooler and washed with water. When the gas generator is operated at high pressures, for example above about 10 atmospheres, small amounts of formic acid may be generated, which dissolves in the water in the digestion cooling zone and in the washing zone. Techniques have been previously disclosed for clarifying digestion cooling water and wash water by removing dispersed solids such as soot and ash. For example, U.S. Patent No. 4014786, which is owned by the applicant.
The specification discloses a technique for using a liquid organic extractant in a decanter to remove soot from areas where carbon is dispersed in water, which is generated during gas digestion, cooling and cleaning. has been done. Also, in commonly owned US Pat. No. 3,544,291, a settling tank is used to separate the clarified water stream from two streams of carbon and ash.

Even if soot and other solids are removed from the digestion cooling and wash waters as described above, cyanide, metal halides, formates, and other by-products of partial oxidation reactions (e.g., ammonia, nickel, etc.) , vanadium, iron, and their oxides and sulfides) remain in small amounts. When water is recycled, these components accumulate in the system.
It corrodes or adheres to downstream equipment. With the method of the present invention, these contaminants can be concentrated as a toxic inorganic cyanide-containing sludge that can be mixed with liquid hydrocarbon fuel and safely disposed of in a partially oxidized gas generator.

The digestion cooling water and washing water from the partial oxidation method of the present invention contain the following impurities (by weight
ppm). i.e. total cyanides (free and bound)...5 to more than 1000 (for example 10 to 100); halides of ammonia or halides of metals selected from the group of sodium, calcium, iron, nickel, and mixtures thereof. …about 25~
20000 (for example 50~5000); Formate...about 100~
20000 (e.g. 500-10000); metals selected from the group of nickel, vanadium, iron and mixtures thereof...approximately 5-1000 each (e.g. approximately 10-250 each); sulfides and thiocyanates...5-5 each 1000 (e.g. 10-250 each);
Ammonia about 0-10000 (for example 100-5000).

At least a portion of the inorganic cyanide-containing sludge, i.e., about 10 to 100 wt. 50wt.%)
to precipitate.

(1) Approximately 15.6 to 99℃ (approximately 60 to 210〓) (for example, approximately
51.7~93.3℃ (125~200〓)), and
Mix ferrous sulfate or ferrous chloride into water at a pH of about 7.0-9.0. By definition PH=−log(H ₃ O ⁺ )
It is. The moles of valent iron ions (ferrous ions) added are approximately 1.2 to 10 (e.g. 2 to 6)
multiplied by the total moles of cyanide contained in the water.

(2) Approximately the same temperature, preferably approximately 51.6 to 93.3℃ (approximately
125~200〓), add sodium hydroxide or calcium hydroxide and mix uniformly, (1)
Raise the pH of the treated water to 9-11. In order to avoid the formation of calcium sulfate (scale) in the system which precipitates at high temperatures as in ammonia stills (strippers), the improved combination of preferred ferrous salts and bases (a) (b) ferrous chloride and calcium hydroxide.

By adding the base, an inorganic cyanide-containing sludge is formed, ie, precipitated, which consists essentially of ash, cyanide, iron sulphides and chlorides. The ash may contain metals and sulfides of metals selected from the group of nickel, vanadium, and iron. Further, when the base is calcium hydroxide as in the above combination (b), in the cyanide-containing sludge,
Calcium carbonate is also present. Furthermore, in special cases when a combination of ferrous sulfate and calcium hydroxide is used, carbonates and sulfates of calcium are also present in the cyanide-containing sludge.

If desired, colloids may then be added by about 0.05 wt.% of a conventional flocculant/coagulant, such as a polyelectrolyte polymer, to increase the rate of precipitation of the inorganic cyanide-containing sludge that occurs in a conventional precipitator. clay or other fillers can be mixed into the sludge-forming mixture.

Sedimentation of the suspension of cyanide-containing sludge in water is carried out in conventional settlers or clarifiers. The downstream toxic sludge stream is then placed in a mixing tank where it is mixed with at least one other liquid hydrocarbon fuel and safely disposed of in a partially oxidized gas generator.

The cyanide-containing sludge is then recovered as slag from the gas generator. Another advantage is obtained when coal is included in the feedstock and the cyanide-containing sludge contains calcium compounds that act as catalysts for the endothermic coal-steam reaction during gasification. In addition, the calcium compound acts as a flux for the ash in the gas generator, thereby lowering the melting temperature of the coal ash. This results in
Syngas generators can be operated at lower temperatures while still producing molten slag.
As a result, the amount of oxygen consumed is reduced, and the operating costs of the gas generator can be significantly reduced.

(3) Most of the ammonia in the almost solids-free overflow from the settler can be removed by steam stripping. Depending on your wishes, for replenishment of base in extinguishing cooling and PH adjustment of washing water in (1), and for base replenishment in PH adjustment of water treated with valent iron ions in (2), You can use that ammonia.

(4) To remove formate and other organic matter present in the stripped water from (3), about 6
Adjust the PH value of the water in the usual manner to a value of ~8. The water is then placed in a conventional biological reactor, converting the formate-containing organic matter into CO ₂ and biological residues that can be safely disposed of without polluting the environment. Alternatively, the biological residue can be mixed with other fuel streams and inorganic cyanide-containing sludge streams and recycled to the partially oxidized gas generator. PH is approx.
The composition of purified water, which is 7.5, contains the following components in ppm or less: That is,
Total cyanide…3.0, free cyanide…1.0,
SCN…1.0, sulfide…1.0, formate…50, NH ₃ …
20, Nickel-vanadium-iron...1, Total suspended solids...40, BOD is 40 without filtration.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

The gas generator 1 is a vertical, cylindrical, unfilled, free-flow, catalyst-free, steel pressure vessel coated with a refractory material 2 on its inner surface. An annular burner 3 is provided at the upper inlet 4 for admitting the reactant feed stream into the reaction zone 5 .

Burner 3 includes a central passage 10 and an annular passage 12. The central passage 10 carries a flow of free oxygen-containing gas from the tube 11 and the annular passage 12 contains
A mixture of hydrocarbon fuel and a temperature moderating agent such as steam from pipe 13 is passed. Fresh liquid hydrocarbon fuel feed from line 14 is sent to mixing tank 17 through lines 15 and 16. In that tank, fresh liquid hydrocarbon fuel is combined with a slurry stream of liquid hydrocarbon soot that has been recycled through line 18 and from the bottom of the settler or clarifier 20 in line 2.
The inorganic cyanide-containing sludge sent to the tank 17 by the pump 19 through 1 to 23 is
mixed. This mixture is passed through pipes 24 and 25 to pipe 13, where it is connected to the temperature softening agent, which is passed through pipe 26 and valve 27, and from the gas cooler 29 to pipes 30 and 31, and the valve. 32 and tube 3
It is mixed with the steam sent through 3 and 25. The by-product steam is either for use elsewhere in this equipment or for use in external equipment.
It can be sent through tube 34 and valve 36 and tube 35. Fresh boiler feed water (BFW) enters the gas cooler 29 through pipe 40.

Raw effluent gas from reaction zone 5 is transferred to chamber 4
1 into two gas streams. Passage 42
The two gas streams in and 43 are simultaneously and separately cooled and washed with water to remove the soot they contain. Therefore, the hot gas flow in the passage 42 is passed through the dip pipe 44 and is extinguished and cooled in the water 45 stored at the bottom of the extinguishing cooling tank 46. A recycle stream of water is admitted into tank 46 through pipe 47.

The extinguishing cooled gas flows through tube 48;
Before entering through the dip pipe 50 into the water 51 that has accumulated at the bottom of the gas washer 52, it is cleaned again in the nozzle washer 49. The gas stream then rises through the shower 53 where it comes into contact with water before exiting through a tube 54 located at the top of the gas scrubber 52 as clean product syngas saturated with water. go. The nozzle washer 49 and the gas washer 53 can be supplied with fresh water or purified recycled water through ports 55 and 56, respectively.

If the primary feedstock to the gas generator consists of an ash-containing solid carbon fuel such as coal, the unchanged carbon and ash and molten slag produced in the reaction zone pass through the dip tube 44. Then, it falls into the water 45 in the fire extinguishing cooling tank 46. Then, the melted slag cools down immediately,
It becomes granular solid particles. Water is supplied through pipe 47 to fire extinguishing cooling tank 46 . The solidified slag or ash and unconverted carbon and refractory bits are optionally removed from tank 46 through pipe 60, valve 61, pipe 62, and conventional lock hopper equipment (not shown). It is taken out. A suitable lock hopper device is disclosed in commonly assigned US Pat. No. 3,544,291. Solid residue and water are discharged from the lock hopper into conventional solid-liquid separation equipment such as a settler, filter or centrifuge (not shown).

In embodiments of this process where the liquid hydrocarbon fuel comprises a slurry of solidified hydrocarbons in a liquid hydrocarbon fuel, or a liquid hydrocarbon such as petroleum, another unreacted carbon is removed in the gas generator. That is, soot is produced which is removed when the gas stream is extinguished and cooled with water 45. In that case,
The soot-in-water liquid from the bottom of the fire extinguishing cooling tank 46 is pumped through pipe 70 .
At 1 the soot is mixed into the dispersed water stream from the pipe 72. The soot-dispersed water stream from tube 72 cools the second stream of hot biosynthesis gas sent through tube 43 by indirect heat exchange with the BFW in gas cooler 29. from,
Obtained by washing with water. That is, the biosynthesis gas in the pipe 73 is washed with water in a normal gas scrubber 75, and the pipe 7
6 exits the gas scrubber 75. The gas flow is
It is cooled to below the dew point in the gas cooler 77.
Separation from water is performed inside a separation tank 79,
A stream of clean, dehydrated product synthesis gas exits through top tube 80.

Cleaning water for the gas scrubbers 52 and 75 is supplied to the pipe 8.
1 to 83 and tubes 81 and 84 to 86, respectively. The cleaning water can be composed of purified water supplied through the pipe 81, fresh water supplied through the pipe 87, valve 88, and pipe 89, and a mixture of these waters.

The liquid in which soot is dispersed in water in the pipe 71 and the pipe 9
5. A recycle portion of the liquid organic extractant, such as naphtha, is routed through the valve and line 97 to line 98.
mixed with each other. The mixture enters the inlet 105, the annular passageway 10 within the conduit subassembly.
6. Through the lower horizontal radial nozzle 107;
It enters the decanter 104 and is discharged below the boundary level. At the same time, the second stage
stage) Naphtha is pipe 109, valve 110, pipe 11
1, through the inlet 112, the conduit 113, the upper horizontal radial nozzle 114, into the boundary level or below it. During the two-stage mixing, the soot is separated from the water and forms a suspension with the liquid organic extractant. In the decanter, naphtha 115 in which particulate carbon soot is dispersed is formed in the upper part of the decanter and floats on water 116.

Water is supplied through pipes 120, 121, pressure reducing valve 122,
The flash column is inserted through the pipe 123.
column) 124. A stream of gaseous impurities containing sulfur exits through line 125 and is sent to the Claus unit for sulfur recovery. When valves 64, 161 are open and valve 65 is closed, at least a portion of the water in pipe 129
That is, about 10-100wt.% (e.g. 20-50wt.%).
%) is treated by a water treatment device (described below). The remainder of the water (if any) from tube 129 is routed through tube 160, valve 161, tube 162,
It can be sent to the fire extinguishing cooling tank 46 and gas scrubbers 52, 75 through other pipes. In this manner, valves 161 and 64 allow deaerated water in pipe 129 to be divided into pipes 160 and 132.

The naphtha-dispersed soot liquid 115 in the upper portion of decanter 104 is conveyed through pipe 155 and mixed with fresh liquid hydrocarbon fuel from pipes 14 and 154 in pipe 156 . Mixing valve 16
7 and the mixture is sent to naphtha distiller 169 through line 168. The naphtha distiller is equipped with a reboiler 170.

Inside the still 169 the naphtha is vaporized and exits the still 169 through the upper tube 171 along with a small amount of H ₂ O. The stream is cooled below the dew point in cooler 172. The liquid naphtha and water mixture is passed through tube 173 into separation vessel 174 . Gaseous impurities are removed through top tube 175 and sent to a Claus device. Water is removed from the bottom of vessel 174 through pipe 176 and pump 177,
123 to the flash column 124.
Naphtha 182 is removed from separation vessel 174 and passed through pipes 183, 184, 185 to decanter 104.
recycled to A portion of the naphtha may be returned to distiller 169 as reflux through line 186. Make-up naphtha, pipe 187 and valve 1
88 and tube 189 into the device.

All liquid hydrocarbon fuel and soot slurry from the bottom of the naphtha still 169 can be recycled to the gas generator as part of the reactant fuel feed. Therefore, the slurry from the bottom of the naphtha still passes through pipes 18 and 16 to mixing tank 17.
where fresh liquid hydrocarbon fuel is fed through pipes 14-16 and pipes 21-23.
The cyanide-containing sludge is mixed with the cyanide-containing sludge sent through the tank.

At least a portion of the flow of flushed dirty water in line 129 or a settler (not shown) to provide a flow of purified water for recycling to fire suppression cooling tank 46 and washers 52, 75. The water flow in tube 67 from or both water flows is placed into mixing tank 63. For example, streams 132 and 6
7 can be processed together in tank 67. Additionally, low soot generating charge materials such as coal and water slurries may not require a decanter area, so valves 64 and 161 are closed and valve 65 is closed.
can be opened. In that case, at least a portion of the other solids, i.e., about 10-100 wt.% (e.g., about 50-90 wt.%), is removed from the water stream from tube 62 with conventional equipment, and the water is then removed from tube 66. ，
67 to the water purification device.

The pH of the water inside the tank 63 is adjusted to a value in the range of 7-9. Ferrous sulfate or ferrous chloride is
It is sent through pipe 68 and reacts with any cyanide and sulfide present in tank 63, converting these materials to iron cyanide and iron sulfide, respectively. The treated wastewater is passed through line 133 to a mixing tank 134 where it is treated with a base from line 136 to adjust the pH to a value of about 9.0-11.0. A sludge containing ferrous cyanide and other compounds settles out.
If desired, bulking agents and polymer flocculants can be added through tube 135 to increase the settling rate. The mixture is then sent to a conventional precipitator 20 via tube 137. After settling, the inorganic cyanide-containing sludge is removed through pipe 21 and transferred to mixing tank 1 as described above.
Sent to 7. The clarified water from settler 20 is passed through pipe 138 to ammonia stripper 1.
39 where the ammonia is removed by steam from tube 140. The NH ₃ and steam exit through tube 141 at the top. The stripped water is sent via line 142 to a conventional biological reactor 143. If desired, the base in tube 141 may be added as part of the base necessary for pH adjustment.
NH ₃ can be sent to tank 63 or 134. The pH of the water from which ammonia has been removed is approximately 6 to 8.
is adjusted to the value of Organic matter, such as formate, is converted into CO ₂ and biological residue in biological reactor 143 , and the CO ₂ is sent through line 144 . Clarified water is removed from biological reactor 143 through tubes 145,81;
The gas is sent to the fire extinguishing cooling tank 45 and the gas scrubbers 52 and 75 as described above. A portion of the clarified water, now environmentally safe, can be discharged from the system through line 146, valve 147, and line 148, if desired. Optionally, the biological residue may be mixed with other reactant fuel feed streams in a mixing tank 17 before it is reacted in the partial oxidation gas generator 1. pipe 149, valve 150, pipes 151,2
It can be sent through 3.

EXAMPLE The following example represents an experimental example of the method of the invention and should not be construed as limiting the scope of the invention.

With final components as below (wt.%)
A slurry containing 3378 tons (3724 tons) of Kentucky bituminous coal per day is reacted by partial oxidation to produce a raw effluent gas stream: C...72.18, H...
4.96, N…1.65, S…3.45, Ash…9.68, O…
8.08.

Approximately 0.2-0.3 wt.% ash, i.e. approx.
979.6Kg (1.08 tons) appears as soluble material in the gas fire cooling and cleaning equipment. To control total dissolved solids to 2500 ppm, approximately 272.5 liters per minute (72
Take a blowdown stream of water (gallons). S...20,
Cyanide...30, SCN...10, _NH3 ...1500, formate...300, ash...200, total inorganic carbon...30.

After removing at least some of the contained solids, the pH of the water is adjusted to about 8. Approximately 82.2℃ (180
〓 At a temperature _of
Mix _7H2O with water. Then, about 0.027 kg (0.06 lb) per 3.79 liters (1 gallon) of water.
Add NaOH. Approximately 540 Kg (approximately 1190 lbs) per day (dry) of inorganic cyanide-containing sludge is precipitated with the following composition (wt% dry): Ash...35.4, FeS...9.8, Fe
(CN) ₂ …5.6, Fe(OH) ₂ …49.2. Depending on your wishes,
To increase the settling rate of the sludge in the settler, conventional flocculants such as polyelectrolyte polymers,
Only about 0.05wt.% of coagulant can be mixed with conventional bulking agents such as colloidal clay.

The inorganic cyanide sludge is then mixed with coal slurry feed as part of the feed to the partially oxidized gas generator.

The overflow water stream from the settler is stripped of NH ₃ in an ammonia stripper and the formate and other organics are reacted in a conventional biological reactor after pH adjustment to about 7. This results in biological residue and clarified water. They are suitable for disposal without affecting the environment. The content of free cyanide and S in clarified water is less than 1 ppm, and formate is less than 1 ppm.
50ppm or less, ammonia is 20ppm or less. This clarified water can be recycled to the firefighting cooling and cleaning areas. Furthermore, the method of the invention allows toxic sludge containing more than 27.000 ppm of cyanide to be safely treated in a gas generator without affecting the environment. In one embodiment of the invention, biological residues are also recycled to the gas generator as part of the feed.

[Brief explanation of the drawing]

The accompanying drawing is a schematic representation of an example of an apparatus for carrying out an embodiment of the method of the invention. 1... Gas generator, 3... Burner, 5... Reaction area, 17... Mixing tank, 20... Precipitator,
29,77...Gas cooler, 46...Fire extinguishing cooling tank, 49...Nozzle washer, 52,53,75
...Gas washer.

Claims (1)

[Claims] 1. For digestion cooling and cleaning of a hot raw effluent gas stream generated in the reaction zone of a partially oxidized gas generator by partial oxidation of a liquid hydrocarbon fuel comprising an oxygenated hydrocarbon fuel and a slurry of solid carbon fuel. The pH of the mixture is adjusted by removing the particulate matter contained in the water used, mixing at least a portion of the water thereby generated with a valent iron salt, and adding an inorganic base to the mixture.
A method for treating toxic inorganic cyanide-containing sludge by adjusting the iron cyanide to a value of about 9 to 11, precipitating the inorganic sludge containing iron cyanide in the water, and separating the inorganic sludge from the water. mixing said inorganic cyanide-containing sludge into at least a portion of said liquid hydrocarbon fuel feed to a reaction zone of a partially oxidized gas generator;
destroying the iron cyanide by reacting the mixture with a free oxygen-containing gas at a temperature in the range of 926-1649°C (about 1700-3000〓) and a pressure in the range of about 1-250 atmospheres; 1. A method for treating generated toxic inorganic cyanide-containing sludge, comprising: recovering the ash of the sludge as part of the slag from a generator.