Waste water processing

• US 3,966,633 A
• Filed: 09/23/1974
• Issued: 06/29/1976
• Est. Priority Date: 09/23/1974
• Status: Expired due to Term

• Current Assignee: Cogas Development Company
• Original Assignee: Cogas Development Company
• Inventors: Friedman, Louis D.
• Primary Examiner(s): Scovronek, Joseph
• Application Number:
  US05/508,395
• Time in Patent Office: 645 Days
• Field of Search: 48/202, 48/197 R, 252/373, 208/8
• US Class Current: 252/373
• CPC Class Codes: C01B 17/167 Separation
• CPC Class Codes: C01B 3/22 by decomposition of gaseous or liquid organic compounds C01B3/0005 takes precedence ; coking liquid carbonaceous materials C10B55/00
• CPC Class Codes: C01B 3/30 using the fluidised bed technique
• CPC Class Codes: C01C 1/10 Separation of ammonia from ammonia liquors, e.g. gas liquors as part of the ammonia synthesis process C01C1/04
• CPC Class Codes: C10G 2300/1003 Waste materials
• CPC Class Codes: C10J 2300/093 Coal
• CPC Class Codes: C10J 2300/0943 Coke
• CPC Class Codes: C10J 2300/1215 using synthesis gas as fuel
• CPC Class Codes: C10J 2300/1615 Stripping
• CPC Class Codes: C10J 2300/1662 to methane
• CPC Class Codes: C10J 2300/169 with water treatments
• CPC Class Codes: C10J 2300/1696 with phase separation, e.g. after condensation
• CPC Class Codes: C10J 3/482 Gasifiers with stationary fluidised bed
• CPC Class Codes: C10J 3/54 Gasification of granular or pulverulent fuels by the Winkler technique, i.e. by fluidisation
• CPC Class Codes: C10J 3/62 with separate withdrawal of the distillation products
• CPC Class Codes: C10K 1/004 Sulfur containing contaminants, e.g. hydrogen sulfide
• CPC Class Codes: C10K 1/005 Carbon dioxide
• CPC Class Codes: C10K 1/101 with water only
• CPC Class Codes: C10K 1/122 containing only carbonates, bicarbonates, hydroxides or oxides of alkali-metals (including Mg)
• CPC Class Codes: C10K 1/143 containing amino groups
• CPC Class Codes: C10K 1/16 : with non-aqueous liquids
• CPC Class Codes: C10K 3/04 : reducing the carbon monoxide content , e.g. water-gas shift [WGS]

Abstract

Waste water formed in the gasification of coal and containing ammonia, H₂ S, and phenolic compounds is treated to remove H₂ S and a substantial proportion of its ammonia, while leaving sufficient ammonia in the water to maintain a pH of at least 8 (such as up to about 10.5, preferably about 8.5 to 9), the ammoniacal water is then flashed into a stream of superheated steam being fed to gasification zone. At the high temperatures in the gasification zone the organic impurities are decomposed.

Claims

1. In a system of synthesis gas manufacture including a gasifier wherein fluidized char is reacted with steam using a particulate heat exchange material to sustain the endothermic steam-carbon reaction to produce a synthesis gas stream which on cooling gives water contaminated with H₂ S and NH₃ and a carbonizer wherein fluidized coal is carbonized below about 700°

C to provide said char and vapors which on cooling give oil and water contaminated with H₂ S and NH₃ and organic materials, the improvement which comprises steam-stripping the contaminated waters to remove the H₂ S but retaining sufficient ammonia to keep the pH between about 8.5 to 10.5 and introducing the resulting treated water into the gasifier to provide at least a portion of the steam requirement therefor while consuming the organic materials.

2. Process as in claim 1 in which said H₂ S is stripped off at a pressure of about 75 to 125 psig, said ammonia is stripped off at a pressure of about 175 to 230 psig, the ammoniacal water remaining after said ammonia stripping has a pH of about 8.5 to 10.5 and a temperature of at least about 200°

C, said stream of superheated steam has a temperature of about 300°

to 600°

C and a pressure of about 150 to 550 psig, and substantially all of the resulting stream of steam is fed into the gasification zone directly.