Process and apparatus for reclaiming sulfur-containing waste materials
AssigneeGrillo-Werke AG
InventorsNorbert Lowiciki, Joachim Wolf, Wolfgang Schwarz
Life of this patent
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Abstract
Disclosed are a process and apparatus useful for reclaiming sulfur-containing waste materials such as waste or spent sulfuric acid and acid tars. The sulfur-containing waste material is burned in a multi-stage combustion furnace having, in sequence, a rotary furnace containing heated coke, an intermediate combustion chamber and a secondary combustion chamber. The temperatures, gas flow rates and amount of added air are carefully controlled. A separation gas is produced having a high sulfur dioxide content which can be used in the sulfuric acid contact process. The separation gas is free of nitrous oxides, hydrocarbons and sulfur trioxide.
Claims12
A process of producing a sulfur dioxide-containing gas from a sulfur-containing waste or spent material, comprising:
- feeding the sulfur-containing material, in a first stage, into a rotary furnace containing a coke bed at a temperature of at least 400.degree. C. together with a sufficient amount of air in the range of about 25 to 55% of the total amount of air supplied in the whole or overall process to form a reducing gas so that the resulting reducing separation gas mixture formed in the furnace is heated to about 800.degree. C. to 1100.degree. C.;
- feeding the reducing separation gas mixture, in a second stage, from the rotary furnace to an intermediate combustion chamber and adding to the reducing gas about 10 to 15% of the total amount of air required in the whole process, and maintaining a volume velocity per hour of about 200 to 400 Nm.sup.3 gas/m.sup.3 of combustion space as the temperature of the gas mixture increases to about 1150.degree. C. to 1350.degree. C.;
- feeding the gas from the intermediate combustion chamber, in a third stage, to the forward combustion space of a secondary combustion chamber and adding to the gas about 20 to 45% of the total amount of air required in the whole process thereby forming a volume velocity per hour of 50 to 180 Nm.sup.3 gas/m.sup.3 of combustion space in the forward combustion space of the secondary combustion chamber as the separation gas cools to a temperature of about 1000.degree. C. to 1200.degree. C.;
- in a fourth stage, feeding the remaining portion of the total air required in the whole process into the center portion of the secondary combustion chamber into admixture with the separation gas therein so that the gas admixture is at about 1000.degree. C. to 1200.degree. C. and a volume velocity per hour of 150 to 400 Nm.sup.3 gas/m.sup.3 of combustion space is thereby obtained;
- removing the resulting sulfur dioxide-containing separation gas from the secondary combustion chamber;
- and
- with the total amount of air supplied in stages one to four providing the separation gas with excess oxygen up to about a 3% oxygen surplus.
A process of producing a sulfur dioxide-containing gas from a sulfur-containing waste or spent material containing organic substances, comprising:
- feeding the sulfur-containing material, in a first stage, into a rotary furnace containing a coke bed at a temperature of at least 400.degree. C. together with a sufficient amount of air in the range of about 25 to 55% of the total amount of air supplied in the whole or overall process to form a reducing gas so that the resulting reducing separation gas mixture formed in the furnace is heated to about 800.degree. C. to 1100.degree. C.;
- feeding the reducing separation gas mixture, in a second stage, from the rotary furnace to an intermediate combustion chamber and adding to the reducing gas about 10 to 15% of the total amount of air supplied in the whole process thereby forming a volume velocity per hour of about 200 to 400 Nm.sup.3 gas/m.sup.3 of combustion space as the temperature of the gas mixture increases to about 1150.degree. C. to 1350.degree. C.;
- feeding the gas from the intermediate combustion chamber, in a third stage, to the forward combustion space of a secondary combustion chamber and adding to the gas about 20 to 45% of the total amount of air supplied in the whole process thereby forming a volume velocity per hour of 50 to 180 Nm.sup.3 gas/m.sup.3 of combustion space in the forward combustion space of the secondary combustion chamber as the separation gas cools to a temperature of about 1000.degree. C. to 1200.degree. C.;
- in a fourth stage, feeding the remaining portion of the total air supplied in the whole process into the center portion of the secondary combustion chamber into admixture with the separation gas therein so that the gas admixture is at about 1000.degree. C. to 1200.degree. C. and a volume velocity per hour of 150 to 400 Nm.sup.3 gas/m.sup.3 of combustion space is thereby obtained;
- removing the resulting sulfur dioxide-containing separation gas from the secondary combustion chamber;
- and
- with the total amount of air supplied in stages one to four providing the separation gas with excess oxygen up to about a 3% oxygen surplus.
Dependencies are inferred from the claim text.