GB1353008A - Fermentation method and fermenter - Google Patents

Abstract

1353008 Fermentation apparatus IMPERIAL CHEMICAL INDUSTRIES Ltd 21 June 1971 [21 July 1970] 35285/70 Heading C6F [Also in Division B1] In the aerobic fermentation of a substrate (hydrocarbon, carbohydrate or methanol) by micro-organisms, the fermentation medium comprising substrate and micro-organisms, is continuously circulated through a system having a compartment 25, Fig. 7, of ascending flow and a compartment 28 of descending flow, air or oxygen is admitted essentially (A) through sparge pipes 27, at or near the lower end of the ascending flow compartment to produce a difference between the hydrostatic pressures at the lower ends of the two compartments sufficient to cause the fermentation medium to circulate continuously between two regions having different hydrostatic pressures, air and/or oxygen being dissolved in the fermentation medium in the region of higher hydrostatic pressure and carbon dioxide produced during fermentation leaving, through part 30, in the region of lower hydrostatic pressure, and (B) through pipe 33 into the compartment of descending flow, the amount of air and/or oxygen admitted to the compartment of descending flow being less than the amount admitted to the compartment of ascending flow. Substrate medium enters the fermenter through pipe 37 whilst product is removed through pipe 35. Additional nutrients such as ammonia may be introduced through pipe 36. Upper section 24 of the ascending flow compartment contains a series of bubble break up devices illustrated as 38. These may be steel or plastics meshes, grids, bars or sieve plates. Downcomer 28 contains heat exchanger 31. In a modification the fermentation system consists essentially of an annular riser 13, Fig. 1, and concentric downcomer 14 separated from one another by wall 15. This wall comprises a series of separate cylindrical sections, each section being of smaller diameter than the section immediately above it. At the junction between each pair of sections, wall 15 is pierced by annular exit ducts 16. The sections are held in position relative to each other by struts 17. Deflector plates 21 below the exit ducts 16 enable liquid passing out of downcomer 14 to be dispersed intimately into the liquid and gas in riser 13. The skirt 20 may be flared outwardly at an angle of 8 degrees. At the upper end of the fermenter, outer and inner walls 12 and 15 slope diagonally outwards, the uppermost section of inner wall 15 terminating in a frustum of a cone (22) through which pass chimneys (23), Fig. 4, (not shown). In another embodiment, the inner wall (15) is pierced by exit ducts (18), the sides (19) of which project into the riser to form scoops Figs. 5 and 6, (not shown).