CA1140847A - Process and apparatus for thermal treatment of sludge - Google Patents
Process and apparatus for thermal treatment of sludgeInfo
- Publication number
- CA1140847A CA1140847A CA000317247A CA317247A CA1140847A CA 1140847 A CA1140847 A CA 1140847A CA 000317247 A CA000317247 A CA 000317247A CA 317247 A CA317247 A CA 317247A CA 1140847 A CA1140847 A CA 1140847A
- Authority
- CA
- Canada
- Prior art keywords
- sludge
- steam
- thickening
- oxidation
- furnace
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F9/00—Measuring volume flow relative to another variable, e.g. of liquid fuel for an engine
- G01F9/001—Measuring volume flow relative to another variable, e.g. of liquid fuel for an engine with electric, electro-mechanic or electronic means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F17/00—Methods or apparatus for determining the capacity of containers or cavities, or the volume of solid bodies
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
Landscapes
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Cooling, Air Intake And Gas Exhaust, And Fuel Tank Arrangements In Propulsion Units (AREA)
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
- Treatment Of Sludge (AREA)
- Measuring Volume Flow (AREA)
- Level Indicators Using A Float (AREA)
Abstract
ABSTRACT
The invention is concerned with a process and an apparatus for the thermal treatment of untreated aqueous sludges which contain combustible matter. The untreated sludge is thermally thickened by heat exchange with oxidation products obtained from oxidation of pre-viously thickened sludge, and the thickened sludge is oxidized to generate gas and steam oxidation products by natural oxidation processes carried out in the gas phase at temperatures above the critical temperature of steam.
The oxidation products are heat exchanged with incoming untreated sludge to thermally thicken the untreated sludge, whereby the steam oxidation product is condensed.
The phases of the oxidation products are then separated and recovered for further uses.
The invention is concerned with a process and an apparatus for the thermal treatment of untreated aqueous sludges which contain combustible matter. The untreated sludge is thermally thickened by heat exchange with oxidation products obtained from oxidation of pre-viously thickened sludge, and the thickened sludge is oxidized to generate gas and steam oxidation products by natural oxidation processes carried out in the gas phase at temperatures above the critical temperature of steam.
The oxidation products are heat exchanged with incoming untreated sludge to thermally thicken the untreated sludge, whereby the steam oxidation product is condensed.
The phases of the oxidation products are then separated and recovered for further uses.
Description
4C~47 Other known processes (so-called wet combustion or wet oxidation) involve combustion of aqueous sludges at elevated temperatures and pressures in a reactor without incineration (flamelessly) and without prior thickening of the sludge, but below the critical temperature of the water.
Due to the prevailing thermodynamic conditions in these processes no steam is formed in the reactor itself, and the liquid reaction products are first expanded and then sub-jected to phase separation in a separator connected to the reactor, whereby the liquid reaction products are separated from the combustion products and steam is recovered or obtained. (See German Published Patent Applications St 2017/IVc/85c of December 8, 1955 (inventor: F.J. Zimmermann) and DE-OS 26117340 of November 4, 1966 (inventor: L.A. Pradt), and Meinck, "Industrial Waste Waters," 4th Edition, 1968, pp. 143-144.) However, in the above wet combustion processes, the reconditioning of the resulting combustion products is relatively expensive, and furthermore, in many cases the products are subjected to a furthercostly aftertreatment because of the hydrocarbons present resulting from the combustion stage.
In German Published Patent Application DE-OS
2304273 published on August 1, 1974 (inventor: Dille et al.), there is disclosed a process for the treatment of sulfide-containing waste waters, wherein the waste waters are mixed with a fuel and converted to synthesis gas at elevated tem-peratures and pressures. Hot synthesis gas from the reactor is quenched, washed and cracked or broken down into its components.
Due to the prevailing thermodynamic conditions in these processes no steam is formed in the reactor itself, and the liquid reaction products are first expanded and then sub-jected to phase separation in a separator connected to the reactor, whereby the liquid reaction products are separated from the combustion products and steam is recovered or obtained. (See German Published Patent Applications St 2017/IVc/85c of December 8, 1955 (inventor: F.J. Zimmermann) and DE-OS 26117340 of November 4, 1966 (inventor: L.A. Pradt), and Meinck, "Industrial Waste Waters," 4th Edition, 1968, pp. 143-144.) However, in the above wet combustion processes, the reconditioning of the resulting combustion products is relatively expensive, and furthermore, in many cases the products are subjected to a furthercostly aftertreatment because of the hydrocarbons present resulting from the combustion stage.
In German Published Patent Application DE-OS
2304273 published on August 1, 1974 (inventor: Dille et al.), there is disclosed a process for the treatment of sulfide-containing waste waters, wherein the waste waters are mixed with a fuel and converted to synthesis gas at elevated tem-peratures and pressures. Hot synthesis gas from the reactor is quenched, washed and cracked or broken down into its components.
-2-~}B~
4~8~7 SUMMARY OF THE INVE~TIO~
An object of this invention is to provide a process and an apparatus for oxidizing aqueous dispersion of sewage sludges and the like which contain combustible or oxidizable dry substances.
Another object of this invention is to provide a process and an apparatus for oxidizing aqueous dispersions of sewage sludges and the like, wherein heat energy obtained from the oxidation of the sludges is almost entirely utilized to supply the total thermal requirements for treatment of the sludges including thickening, i.e. the total thermal treat-ment of sludges is carried out solely with the heat energy obtained from the oxidation of the sludges, without the need for using additional fuels.
A further object of this invention is to pro-vide a process and an apparatus for oxidizing aqueous dis-persions of sewage sludges and the like wherein dissolved salts contained in the untreated sludge are retained in the residual water of the dehydrated sludge during the ' thermal treatment process.
In accordance with a broad aspect of the in-vention, there is thus provided a process for the thermal treatment of untreated aqueous sludges which contain com-bustible matter, comprising thermally thickening the un-treated sludge by heat exchange with oxidation products obtained from oxidation of previously thickened sludge, oxidizing the thickened ~ludge to generate ~as and steam oxidation products by natural oxidation processes carried out in the gas phase at temperatures above the critical temperature of steam. Heat exchanging the oxidation products with incoming untreated sludge to thermally thicken,the untreated sludge, whereby the steam
4~8~7 SUMMARY OF THE INVE~TIO~
An object of this invention is to provide a process and an apparatus for oxidizing aqueous dispersion of sewage sludges and the like which contain combustible or oxidizable dry substances.
Another object of this invention is to provide a process and an apparatus for oxidizing aqueous dispersions of sewage sludges and the like, wherein heat energy obtained from the oxidation of the sludges is almost entirely utilized to supply the total thermal requirements for treatment of the sludges including thickening, i.e. the total thermal treat-ment of sludges is carried out solely with the heat energy obtained from the oxidation of the sludges, without the need for using additional fuels.
A further object of this invention is to pro-vide a process and an apparatus for oxidizing aqueous dis-persions of sewage sludges and the like wherein dissolved salts contained in the untreated sludge are retained in the residual water of the dehydrated sludge during the ' thermal treatment process.
In accordance with a broad aspect of the in-vention, there is thus provided a process for the thermal treatment of untreated aqueous sludges which contain com-bustible matter, comprising thermally thickening the un-treated sludge by heat exchange with oxidation products obtained from oxidation of previously thickened sludge, oxidizing the thickened ~ludge to generate ~as and steam oxidation products by natural oxidation processes carried out in the gas phase at temperatures above the critical temperature of steam. Heat exchanging the oxidation products with incoming untreated sludge to thermally thicken,the untreated sludge, whereby the steam
-3-8g7 oxidation product is condensed, and separating and recovering for further uses the phases of the oxidation products.
According to another broad aspect of the inven-tion, there is provided in a process for the thermal treatment of aqueous sludges, in particular of clarification sludges, in which the sludge is thickened by indirect heat exchange, using the combustion heat, and then oxidized by being subjected to combustion at elevated temperatures. The improvement wherein:
(a) the combustion takes place under excess pressure in a pressure-tight furnace, in the gas phase at temperaturesabove the critical temperature of steam, (b) the sensible heat and heat of condensation contained in the resulting pressurized mixture of steam and combustion gas is coupled to following heat exchangers and applied to preheating the combustion air, to pre-heating the sludge, and to thickening the sludge; and (c) the phases of combustion gas, steam and condensate arising in the thermal thickening are separately drawn off and supplied for a further utilization.
According to yet a further aspect of the in-vention, there is provided an apparatus for the thermal treatment of untreated aqueous sludges which contain com-bustible matter, comprising thin layer evaporator means connected to oxidation furnace means, the outer chamber of the evaporator means being in communication with oxidation products exiting from the furnace means whereby sludge entering the inner chamber of the evaporator means is thermally thickened by heat exchange with the oxidation products, and the furnace means communicating with the -3a-inner chamber of the evaporator means for passage of the thermally thickened sludge from the evaporator means to the furnace means.
For a better understanding of the present invention, together with other and further objects and features thereof, reference is had to the following de-tailed description of a preferred embodiment taken in con-junction with the accompanying drawing.
-3b-I SAA-ll 8~
DETAILED DESCRIPTION OF THE INVEMTION
The process of this invent~on will be better understood ¦by way of example with reference to the accompanying drawing which is a schematic depiction of the apparatus for carrying out the process.
Sludge from a clarification plant with 95% water conten~
in line 24 is pumped by pump 16 through heat exchangers 14 and 17 and into a preliminary concentrator and/or sieve separator 1.
The sludge settles to the bottom of the concentrator, exits through line 25 into a sludge disintegr,ator 20 and is pumped therefrom in line 26 by pump 21 through a heat exchanger 18 and into heating chamber 27 of a thin layer evaporator 2. The thickened sludge containing 80% water exits from the evaporator through line 28 and i8 pumped by pump 9 through heat exchanger 7, wherein it is heated to a temperature of about 200 C., and passed into furnace 3, wherein it is oxidized, i.e. it is either burned or carbonized at low temperature (degassed) or is gasified.
Ashes from the burned sludge are drawn off through exhaust line
According to another broad aspect of the inven-tion, there is provided in a process for the thermal treatment of aqueous sludges, in particular of clarification sludges, in which the sludge is thickened by indirect heat exchange, using the combustion heat, and then oxidized by being subjected to combustion at elevated temperatures. The improvement wherein:
(a) the combustion takes place under excess pressure in a pressure-tight furnace, in the gas phase at temperaturesabove the critical temperature of steam, (b) the sensible heat and heat of condensation contained in the resulting pressurized mixture of steam and combustion gas is coupled to following heat exchangers and applied to preheating the combustion air, to pre-heating the sludge, and to thickening the sludge; and (c) the phases of combustion gas, steam and condensate arising in the thermal thickening are separately drawn off and supplied for a further utilization.
According to yet a further aspect of the in-vention, there is provided an apparatus for the thermal treatment of untreated aqueous sludges which contain com-bustible matter, comprising thin layer evaporator means connected to oxidation furnace means, the outer chamber of the evaporator means being in communication with oxidation products exiting from the furnace means whereby sludge entering the inner chamber of the evaporator means is thermally thickened by heat exchange with the oxidation products, and the furnace means communicating with the -3a-inner chamber of the evaporator means for passage of the thermally thickened sludge from the evaporator means to the furnace means.
For a better understanding of the present invention, together with other and further objects and features thereof, reference is had to the following de-tailed description of a preferred embodiment taken in con-junction with the accompanying drawing.
-3b-I SAA-ll 8~
DETAILED DESCRIPTION OF THE INVEMTION
The process of this invent~on will be better understood ¦by way of example with reference to the accompanying drawing which is a schematic depiction of the apparatus for carrying out the process.
Sludge from a clarification plant with 95% water conten~
in line 24 is pumped by pump 16 through heat exchangers 14 and 17 and into a preliminary concentrator and/or sieve separator 1.
The sludge settles to the bottom of the concentrator, exits through line 25 into a sludge disintegr,ator 20 and is pumped therefrom in line 26 by pump 21 through a heat exchanger 18 and into heating chamber 27 of a thin layer evaporator 2. The thickened sludge containing 80% water exits from the evaporator through line 28 and i8 pumped by pump 9 through heat exchanger 7, wherein it is heated to a temperature of about 200 C., and passed into furnace 3, wherein it is oxidized, i.e. it is either burned or carbonized at low temperature (degassed) or is gasified.
Ashes from the burned sludge are drawn off through exhaust line
4 and will be further described below.
Oxidation gases and steam as a mixture exit from the furnace through line 29 and pass through heat exchanger 5, line 8, heat exchanger 7, line 30, filter 10, and line 31 into outer heating chamber 11 of exaporator 2, wherein the gases and steam indirectly heat the sludge in the inner, thin layer heating cham~er 27, whereby the steam is condensed and the combustion gases exit through line 32, pass through a filter 12, and enter into an expansion engine 13. The filter 10 in line 8 removes ashes, dust and particles from the gas-steam mixture.
The gas and steam, at a temperature of about 1000 C., leaving furnace 3 through line 29 into heat exchanger 5 release , ll SAA-ll I
1~4~384~;~
part of their heat to combustion air, oxygen, or any other oxygen-air mixture entering in line 38. The combustion air is thereby preheated to about 800 C. and is blown into furnace 3 from line 39.
The combustion gases after having passed through the outer chamber of evaporator 2, filter 12, and engine 13 can be utilized as combustion or synthesis gases.
The condensed steam in outer chamber 11 of the evaporator, which still has a temperature of about 170 C. and a superpressure of about 20 bar, is withdrawn through line 33, passed into heat exchanger 14 to preheat the entering sludge, and is subsequently expanded in an expansion engine 15 and diverted.
The sludge in inner thin layer chamber 27 of evaporator 11 boils at a temperature of about 150 C. and about 3 bar super-pressure. The steam produced exists through line 34 into lines 35 and 36. From line 35, the steam passes into heat exchanger 18, which heats the sludge passing through line 26 before the sludge enters the evaporator 2. From line 36, the steam passes through lines 37 and 23. From line 37, the steam passes into heat exchanger 17 which heats the sludge passing through line 24 before it enters the preliminary concentrator 1. From line 23, excess steam is drawn off for other uses. After the steam has passed through heat exchangers 17 and 18, the steam is sub-sequently expanded as steam or condensate in expansion engines 1~ and 22, respectively, and diverted.
In the above process wherein the sludge is preheated with the products of the combustion thereof, dissolved matter in the sludge ~ater, e.g., albumen, is eliminated, whereby few or no precipitants are required for removal of the dissolved matter.
However, advantageously, materials to bond pollutants in the SAA-ll il4~847 sludge, such as sulfur and he~v~ metals, in particular, can be added during treatment of the sludge in order to render the ashes directly depositabIe andlor to produce clean gases emitting from the furnace 3.
The salts originally dissolved in the sludge water and remaining in the residual water of the thermally thickened sludge contribute to a higher salt concentration therein and some salts, i.e. sodium a~d magnesium compounds, act as dissolu-tion agents, and therefore greatly reduces or entirely eliminates the need for the addition of dissolving agents.
The various salts which are contained in the original untreated sludgP are still present in the ashes drawn off by exhaust line 4. These various soluble salts in the ashes are particularly suitable for use as agricultural fertilizer. If dissolution agents are added to the sludge before or during oxidation, the phosphates or other fertilizer compounds in the ashes are rendered more water or citric acid soluble, and as such are more readily accepted by agricultural plants. In addition, other salts contained in the residual water of the sludge can 2Q effect dissolution.
In the above described process, the invention is charac-terized by the fact that the inner chamber 27 of the thin layer evaporator 2 is connected on one side to the entering sludge and on the other side to the sludge entry of furnace 3, and that the gas side of the furnace is in communication with the outer chamber 11 of the evaporator.
It is to be understood that oxidation in the process of this invention other than combustion can also include low temperatu~e carbonization or gasification. Thus, in gasification, ~ SAA ll 1~L4~847 the sludge having a water content of about 80% can be burned in furnace 3 at a pressure of about 20 bar and a temperature of about lOOQ C. resulting in the formation of gases, steam and ashes. In this regard, the furnace 3 is constructed to be pressure resiætant and can be a muffle furnace, slag tap furnace, blast furnace, or a fluidized bed furnace of sand or granulated ashes.
In the oxidation part of the process, conventional fuels, waste oil or general waste materials can be added to optimize the process on the one hand while on the other hand disposing .
of waste materials in an economical manner or in aiding in its recycling. Thus, it is conceivable to subject fuels, waste oil, used tires, garbage or other general waste materials, if necessary, subsequent to preliminary or pretreatment thereof, partly or entirely to the process of the invention. More significantly, however, than the above variations of the process, is the fact that there is a total combustion possible o~ the excess oxygen.
The process of the invention is also chara~terized and .produces an eusential.advantage in that the thermal energy requirements for the individual steps of the thermal treatment of the sludge is energy entirely regained from energy which is released from oxidizing the sludge in the furnace and, further- :.
more, that this energy is then utilized in its entirety by con-densing the steam contained in the gas-steam mixture obtained from the furnace.
In the thermal thickening of the sludge, it is preferable to carry out the process in several stages whereby the steam produced during thickening in one step is used for thickening ll SAA-ll f the s1udge in a previous step, and the steam w~ich ls the product of the thickening is cooled or condensed-in heat exchange with the sludge to be heated. In addition, because the condensed steam still contains residual heat, it may further be used for thermal treatment of the sludge by heat exchange. Energy can even be recovered from the gases still under pressure by the use of expansion engines.
It is to be understood that the concept of the invention is not limited to the specific embodiment set forth above, but can also comprise treatment plants for various sludges such as industrial sludges containing matter combustible in its dry state or in a slurry, or to sludges to which combustible matter is added.
Oxidation gases and steam as a mixture exit from the furnace through line 29 and pass through heat exchanger 5, line 8, heat exchanger 7, line 30, filter 10, and line 31 into outer heating chamber 11 of exaporator 2, wherein the gases and steam indirectly heat the sludge in the inner, thin layer heating cham~er 27, whereby the steam is condensed and the combustion gases exit through line 32, pass through a filter 12, and enter into an expansion engine 13. The filter 10 in line 8 removes ashes, dust and particles from the gas-steam mixture.
The gas and steam, at a temperature of about 1000 C., leaving furnace 3 through line 29 into heat exchanger 5 release , ll SAA-ll I
1~4~384~;~
part of their heat to combustion air, oxygen, or any other oxygen-air mixture entering in line 38. The combustion air is thereby preheated to about 800 C. and is blown into furnace 3 from line 39.
The combustion gases after having passed through the outer chamber of evaporator 2, filter 12, and engine 13 can be utilized as combustion or synthesis gases.
The condensed steam in outer chamber 11 of the evaporator, which still has a temperature of about 170 C. and a superpressure of about 20 bar, is withdrawn through line 33, passed into heat exchanger 14 to preheat the entering sludge, and is subsequently expanded in an expansion engine 15 and diverted.
The sludge in inner thin layer chamber 27 of evaporator 11 boils at a temperature of about 150 C. and about 3 bar super-pressure. The steam produced exists through line 34 into lines 35 and 36. From line 35, the steam passes into heat exchanger 18, which heats the sludge passing through line 26 before the sludge enters the evaporator 2. From line 36, the steam passes through lines 37 and 23. From line 37, the steam passes into heat exchanger 17 which heats the sludge passing through line 24 before it enters the preliminary concentrator 1. From line 23, excess steam is drawn off for other uses. After the steam has passed through heat exchangers 17 and 18, the steam is sub-sequently expanded as steam or condensate in expansion engines 1~ and 22, respectively, and diverted.
In the above process wherein the sludge is preheated with the products of the combustion thereof, dissolved matter in the sludge ~ater, e.g., albumen, is eliminated, whereby few or no precipitants are required for removal of the dissolved matter.
However, advantageously, materials to bond pollutants in the SAA-ll il4~847 sludge, such as sulfur and he~v~ metals, in particular, can be added during treatment of the sludge in order to render the ashes directly depositabIe andlor to produce clean gases emitting from the furnace 3.
The salts originally dissolved in the sludge water and remaining in the residual water of the thermally thickened sludge contribute to a higher salt concentration therein and some salts, i.e. sodium a~d magnesium compounds, act as dissolu-tion agents, and therefore greatly reduces or entirely eliminates the need for the addition of dissolving agents.
The various salts which are contained in the original untreated sludgP are still present in the ashes drawn off by exhaust line 4. These various soluble salts in the ashes are particularly suitable for use as agricultural fertilizer. If dissolution agents are added to the sludge before or during oxidation, the phosphates or other fertilizer compounds in the ashes are rendered more water or citric acid soluble, and as such are more readily accepted by agricultural plants. In addition, other salts contained in the residual water of the sludge can 2Q effect dissolution.
In the above described process, the invention is charac-terized by the fact that the inner chamber 27 of the thin layer evaporator 2 is connected on one side to the entering sludge and on the other side to the sludge entry of furnace 3, and that the gas side of the furnace is in communication with the outer chamber 11 of the evaporator.
It is to be understood that oxidation in the process of this invention other than combustion can also include low temperatu~e carbonization or gasification. Thus, in gasification, ~ SAA ll 1~L4~847 the sludge having a water content of about 80% can be burned in furnace 3 at a pressure of about 20 bar and a temperature of about lOOQ C. resulting in the formation of gases, steam and ashes. In this regard, the furnace 3 is constructed to be pressure resiætant and can be a muffle furnace, slag tap furnace, blast furnace, or a fluidized bed furnace of sand or granulated ashes.
In the oxidation part of the process, conventional fuels, waste oil or general waste materials can be added to optimize the process on the one hand while on the other hand disposing .
of waste materials in an economical manner or in aiding in its recycling. Thus, it is conceivable to subject fuels, waste oil, used tires, garbage or other general waste materials, if necessary, subsequent to preliminary or pretreatment thereof, partly or entirely to the process of the invention. More significantly, however, than the above variations of the process, is the fact that there is a total combustion possible o~ the excess oxygen.
The process of the invention is also chara~terized and .produces an eusential.advantage in that the thermal energy requirements for the individual steps of the thermal treatment of the sludge is energy entirely regained from energy which is released from oxidizing the sludge in the furnace and, further- :.
more, that this energy is then utilized in its entirety by con-densing the steam contained in the gas-steam mixture obtained from the furnace.
In the thermal thickening of the sludge, it is preferable to carry out the process in several stages whereby the steam produced during thickening in one step is used for thickening ll SAA-ll f the s1udge in a previous step, and the steam w~ich ls the product of the thickening is cooled or condensed-in heat exchange with the sludge to be heated. In addition, because the condensed steam still contains residual heat, it may further be used for thermal treatment of the sludge by heat exchange. Energy can even be recovered from the gases still under pressure by the use of expansion engines.
It is to be understood that the concept of the invention is not limited to the specific embodiment set forth above, but can also comprise treatment plants for various sludges such as industrial sludges containing matter combustible in its dry state or in a slurry, or to sludges to which combustible matter is added.
Claims (22)
1. A process for the thermal treatment of untreated aqueous sludges which contain combustible matter, comprising thermally thickening said untreated sludge by heat exchange with oxidation products obtained from oxi-dation of previously thickened sludge, oxidizing said thickened sludge to generate gas and steam oxidation pro-ducts by natural oxidation processes carried out in the gas phase at temperatures above the critical temperature of steam, heat exchanging said oxidation products with incoming untreated sludge to thermally thicken said un-treated sludge, whereby said steam oxidation product is condensed, and separating and recovering for further uses the phases of said oxidation products.
2. The process of claim 1, wherein said thermal thickening of said sludge is carried out in several stages and wherein steam produced in the thickening of a stage is used for thermal thickening of a previous stage.
3. The process of claim 1, wherein said untreated sludge is initially heat exchanged with steam or condensate produced in subsequent thermal thickening stages.
4. The process of claim 1, wherein one or more bonding agents are added to the sludge to bond pollutants contained in the sludge, whereby suitable fertilizer com-ponents are formed in the sludge.
5. The process of claim 1, wherein additional combustible waste matter is added to the sludge.
6. The process of claim 1, wherein said untreated sludge is initailly heat exchanged with steam from said oxidation step, concentrated, thermally thickened by thin layer evaporation in heat exchange with oxidation products from said oxidation step, and oxidized at elevated tempera-tures and pressures in said oxidation step.
7. The process of claim 1, wherein steam con-tained in said oxidation products is expanded to obtain residual energy after said steam has been heat exchanged with said sludge to thermally thicken said sludge.
8. The process of claim 1, wherein combustion gases contained in said oxidation products are expanded to obtain residual energy after said gases have been heat exchanged to thermally thicken said sludge.
9. The process of claim 1, wherein the oxidizing of thickened sludge is carried out without the use of additional fuels.
10. In a process for the thermal treatment of aqueous sludges, in particular of clarification sludges, in which the sludge is thickened by indirect heat exchange, using the combustion heat, and then oxidized by being subjected to combustion at elevated temperatures, the improvement wherein:
(a) the combustion takes place under excess pressure in a pressure-tight furnace, in the gas phase at temperatures above the critical temperature of steam, (b) the sensible heat and heat of condensation contained in the resulting pressurized mixture of steam and combustion gas is coupled to following heat exchangers and applied to preheating the combustion air, to preheating the sludge, and to thickening the sludge, and (c) the phases of combustion gas, steam and condensate arising in the thermal thickening are separately drawn off and supplied for a further utilization.
(a) the combustion takes place under excess pressure in a pressure-tight furnace, in the gas phase at temperatures above the critical temperature of steam, (b) the sensible heat and heat of condensation contained in the resulting pressurized mixture of steam and combustion gas is coupled to following heat exchangers and applied to preheating the combustion air, to preheating the sludge, and to thickening the sludge, and (c) the phases of combustion gas, steam and condensate arising in the thermal thickening are separately drawn off and supplied for a further utilization.
11. The process of claim 10, wherein the thicken-ing takes place in several stages, and the steam arising on thickening in one stage is used for thickening in a pre-vious stage.
12. The process of claim 10, wherein the thickening is carried out in a thin layer evaporator and the steam and exhaust vapors arising in thickening in said thin layer evaporator is utilized for preheating of sludge, and for driving flash machines, and is supplied for further utilization.
13. The process of claim 10, wherein the con-densate water arising on thickening is utilized for sludge preheating and for driving flash machines.
14. The process of claim 10, wherein the energy of the flue gas separated in thickening is used in one or more flash machines.
15. The process of claim 10, wherein there is added to the sludge one or more media for binding injurious materials, fertilizer formation, or precipitation.
16. The process of claim 10, wherein there are added to the sludge additional combustible materials and also other wastes, if necessary after corresponding pre-paration.
17. The process of claim 10, wherein the energy of the pressurized flue gas, steam and condensate water is utilized in flash machines.
18. The process of claim 10, wherein the sludge is concentrated in a concentrator after an initial pre-heating and is thereafter pumped into a thin layer eva-porator.
19. The process of claim 10, wherein the oxi-dation is achieved, alternatively, by any of the following three methods: (1) burning, (2) carbonization or (3) gasification
20. The process of claim 10, wherein the oxi-dation of the sludge takes place, alternatively, in a muffle furnace, a slag tap furnace, a blast furnace, or a fluidized bed furnace.
21. An apparatus for the thermal treatment of untreated aqueous sludges which contain combustible matter, comprising thin layer evaporator means connected to oxi-dation furnace means, the outer chamber of said evaporator means being in communication with oxidation products exiting from said furnace means whereby sludge entering the inner chamber of said evaporator means is thermally thickened by heat exchange with said oxidation products, and said fur-nace means communicating with the inner chamber of said evaporator means for passage of said thermally thickened sludge from said evaporator means to said furnace means.
22. The apparatus of claim 21, further including concentrating means and heat exchange means for thickening said sludge prior to entry of said sludge into said evaporator means, and line means for passage of steam from said evaporator means through said heat exchange means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP275371-41 | 1977-12-01 | ||
| DE19772753714 DE2753714C2 (en) | 1977-12-02 | 1977-12-02 | Device for measuring and displaying values related to fuel consumption |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1140847A true CA1140847A (en) | 1983-02-08 |
Family
ID=6025156
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000317247A Expired CA1140847A (en) | 1977-12-01 | 1978-12-01 | Process and apparatus for thermal treatment of sludge |
Country Status (6)
| Country | Link |
|---|---|
| AU (1) | AU4190678A (en) |
| BR (1) | BR7807803A (en) |
| CA (1) | CA1140847A (en) |
| DE (1) | DE2753714C2 (en) |
| FR (1) | FR2410810A1 (en) |
| GB (1) | GB2009417B (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT7953796V0 (en) * | 1979-12-13 | 1979-12-13 | Fiat Auto Spa | DATA PROCESSING DEVICE DEPENDING ON FUEL CONSUMPTION IN A VEHICLE |
| ES8304302A1 (en) * | 1981-12-11 | 1983-03-01 | Espanola Automoviles Turismo | A fuel consumption indicating device for a motor vehicle |
| WO1983002322A1 (en) * | 1981-12-28 | 1983-07-07 | Kobayashi, Hiroshi | Fuel gauge for automobile |
| GB2138947B (en) * | 1983-04-14 | 1986-10-08 | Chiltern Glass Fibres Limited | Improvements in or relating to a method of control of liquid stock |
| GB2254150A (en) * | 1991-03-23 | 1992-09-30 | Ford Motor Co | Low liquid level warning system |
| DE19621896A1 (en) * | 1996-05-31 | 1997-12-04 | Man Nutzfahrzeuge Ag | Tachometer with economometer |
| DE19702393A1 (en) * | 1997-01-24 | 1998-07-30 | Audi Ag | Method for determining the fuel consumption of a vehicle |
| FR2759455A1 (en) * | 1997-02-13 | 1998-08-14 | Bacot Dominique | Liquid gas level measuring device for domestic fuel tank |
| DE19834165B4 (en) * | 1998-07-29 | 2009-12-10 | Volkswagen Ag | Fuel gauge for a fuel tank of a motor vehicle |
| DE10208917B4 (en) | 2002-02-27 | 2019-02-07 | Volkswagen Ag | Method and device for displaying information of operating fluids |
| US7059167B2 (en) * | 2003-01-31 | 2006-06-13 | Ab Volvo Penta | Method and arrangement for indirectly determining fill characteristics of a fluid tank on a marine vessel |
| DE102004008037A1 (en) * | 2004-02-19 | 2005-09-15 | Opel Eisenach Gmbh | Vehicle fuel tank fuel level sensor unit combines float reading with instantaneous fuel consumption for engine control unit |
| DE102004021096A1 (en) * | 2004-04-29 | 2005-12-01 | Adam Opel Ag | Vehicle fuel tank level determination procedure records amount used and subtracts from measured or manually entered original amount |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3529472A (en) * | 1968-12-05 | 1970-09-22 | Gen Motors Corp | Float-operated thermistor tank level sender |
| DE2418860A1 (en) * | 1974-04-19 | 1975-10-30 | Kuebler Impulsgeraete | TRANSDUCER FOR LEVEL INDICATOR OF LIQUIDS |
| DE2446907A1 (en) * | 1974-10-01 | 1976-05-13 | Robert Heidenreich Inh Frank H | Inductive remote-reading liquid-lever gauge for container - is fitted with weight made of buoyant material balanced out by spring |
-
1977
- 1977-12-02 DE DE19772753714 patent/DE2753714C2/en not_active Expired
-
1978
- 1978-11-23 GB GB7845755A patent/GB2009417B/en not_active Expired
- 1978-11-24 AU AU41906/78A patent/AU4190678A/en active Pending
- 1978-11-28 BR BR7807803A patent/BR7807803A/en unknown
- 1978-12-01 FR FR7833997A patent/FR2410810A1/en active Granted
- 1978-12-01 CA CA000317247A patent/CA1140847A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2009417A (en) | 1979-06-13 |
| GB2009417B (en) | 1982-09-02 |
| DE2753714A1 (en) | 1979-06-07 |
| BR7807803A (en) | 1979-07-31 |
| AU4190678A (en) | 1979-06-07 |
| FR2410810A1 (en) | 1979-06-29 |
| DE2753714C2 (en) | 1986-11-13 |
| FR2410810B3 (en) | 1981-09-18 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |