Liquid purification or separation – Recirculation – Serially connected distinct treating or storage units
Patent
1993-03-19
1994-08-16
Upton, Christopher
Liquid purification or separation
Recirculation
Serially connected distinct treating or storage units
210202, 2102571, 210261, 210603, 2105121, C02F 328
Patent
active
053384474
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a bioreactor comprising a reactor vessel having an inlet system for influent or a mixture of influent and recycled material and a reaction chamber located above this system.
Reactors of this type are used to treat fluids (anaerobically or aerobically), or to prepare substances such as alcohol, with the aid of a biomass.
In the field of anaerobic treatment of waste water, new types of reactors having a high load-taking capacity have been developed in recent years, which reactors are characterised by very high volume loads, a relatively small reaction volume and a slimline high construction. The main types are: material or adhesion material for the biomass (see EP-A-0090450)), expanded bed, and circulation of the reactor contents (see EP-A-0170332).
A difficult point with these reactors is the distribution of the influent, which may be mixed with the recycled effluent, over the bottom surface of the reactor. Influent distribution systems are disclosed in EP-B-0090450 (Gist-Brocades), EP-A-0169620 (Paques) and U.S. Pat. No. 4,202,774 (Doff Oliver). In general, a distribution of the influent stream over the reactor bottom such that the sludge bed is subject to a completely stable fluidisation or expansion is not achieved with these systems. The consequence of this is the generation of short-circuit flows and dead corners.
It is known to improve the distribution of the influent by bottom, fop example by means of a pipe system, and in order to create a pressure drop which leads to a uniform distribution as a result of dissipation of energy.
These inlet systems, which in themselves operate satisfactorily, are subject to a number of disadvantages: If sand or another hard material is present as carrier material, the influent distribution system will undergo enormous wear as a result of the sand blasting effect. If the reactor is temporarily taken out of operation, the sludge bed settles and this causes difficulties in restarting the installation and, moreover, sludge particles can flow back into the distribution system, as a result of which blockages are formed.
The aim of the invention is to overcome these drawbacks and to provide a bioreactor, indicated in the preamble, which produces an excellent distribution of the influent (which may be mixed with recycled material) without there being a risk of blockage and without excessive wear problems arising.
According to the invention, to this end the outflow openings of the influent inlet system are at least partially tangentially oriented and the influent inlet system is located in a chamber which is separated from the reaction chamber by a partition which has at least one radial slit, formed by two radial edge strips vertically overlapping one another some distance apart, which radial slit forms the connection between the said influent inlet chamber and the reaction chamber.
An even better distribution results as a consequence of constructing the partition from two or more segments which partially overlap one another.
Preferably, the partition has an essentially conical shape. An advantage of this is that the material transport from the influent inlet chamber to the reaction chamber also takes place if the inlet chamber is in- completely filled.
It is known per se to use a downcomer to return recycled material to the influent inlet system (see, for example, EP-B-0170332). In this case, the downcomer can also have an outflow opening which is at least partially tangentially oriented.
The said radial slit or slits have n height of between 0.25 and 10 cm, preferably between 0.5 and 3.0 cm. The radial edge strips of the partition overlap one another over a length of 0.5-50 cm, preferably 2.5-25 cm.
Packing pieces can be placed in the slit or slits in order to reduce the passage surface of the slit or slits. The flow rate in the slits will consequently be increased, which leads to a greater pressure drop over the slits and thus to e better distribution.
The invention will now be illustrated in more detail with reference to the figures.
FIG. 1 shows
REFERENCES:
patent: 2874118 (1959-02-01), Albertson
patent: 3390076 (1968-06-01), Dubach
patent: 4096065 (1978-06-01), Brach et al.
patent: 4280902 (1981-07-01), Jacobson et al.
patent: 4447322 (1984-05-01), Zajellik
patent: 4663046 (1987-05-01), Feldkirchner et al.
Paques B.V.
Upton Christopher
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