Sugar – starch – and carbohydrates – Processes – Carbohydrate manufacture and refining
Patent
1997-03-14
1999-03-30
Bell, Mark L.
Sugar, starch, and carbohydrates
Processes
Carbohydrate manufacture and refining
34 15, 422110, 210750, 210774, 210609, C13K 102, G05D 700, B01D 3518, C02F 300
Patent
active
058883070
DESCRIPTION:
BRIEF SUMMARY
The present application relates to a method and apparatus for the hydrolysis of organic material.
Norwegian Published Patent Application No. 160907 makes known a method for preparing a reaction product, and also an apparatus for carrying out the method. This publication describes a process wherein two autoclaves/pressure vessels are connected to one another. In order to achieve good economy of heat, heat exchangers are used which, e.g., heat water which is to be mixed with chemicals in the tank 10. When the material is to be transferred from the tank 10 to the tank 12, this takes place in that the pressure in tank 12 is raised so that the pressure difference between the two tanks is as small as possible. The object of this is to achieve a gentle and preferably laminar transfer from the tank 10 to the tank 12, as the product will otherwise be ruined. The method described in this publication is especially intended for the preparation of calcium silicate and is totally unsuitable for carrying out hydrolysis of organic material.
Norwegian Published Patent Application No. 173372 makes known a method and apparatus for preparing a reaction product which would seem to be a further development of the method and apparatus described in Norwegian Published Patent Application No. 160907. The principle of the method according to these two patents would seem, at the point of departure, to be identical.
U.S. Pat. No. 3,525,596 and GB 1 375 741 make known the sluicing out of solid matter in a high pressure process from a liquid stream by using interconnected tanks, which according to need can be pressurised for sluicing out with minimum wear on the valves. Neither of these publications is capable of achieving the objects of the present application.
From the literature it is known that heat treatment of organic material in the temperature range of from 160.degree. C. to 240.degree. C. causes the hydrolysis (decomposition in water) of a considerable portion of the organic material. On this basis, a thermal pre-treatment of organic material such as, e.g., sewage sludge, waste, wet organic wood and other organic materials, has been developed. This method makes use of a regenerative hydrolysis reactor using stepwise heating where high pressure steam is used twice in order to minimise energy consumption.
Relatively short periods in the pre-treatment (5-120 minutes) means that it is not necessary to have tanks of large volume, thereby giving lower energy costs. It is thus possible to treat large amounts of organic material in structures of a relatively small volume.
On the pre-treatment of, e.g., sludge, a degradation of organic material into smaller particles will be obtained, which makes it possible to digest the sludge of high dry matter content. The pre-treatment also means that the nutrients will be more easily accessible to bacteria.
By using this pre-treatment in sludge processing plants, a simultaneous pasteurisation and sanitation of the sludge is achieved. It will then also be possible to reduce the amount of residual sludge after the digestion.
A thermal hydrolysis of organic material can be carried out in two ways. The process is run either by means of indirect heating or direct heating using, e.g., steam. In some cases, acid has also been added in order to obtain enhanced hydrolysis.
In indirect heating plants, the heat treatment takes place in heat exchangers. In terms of thermodynamics, this is a good method as it is easy to achieve a good heat exchange. In practice, this method causes operational problems because of the build-up of fouling on the heating surface, as well as problems of wear in pressure reduction valves.
The direct process is in many ways simpler. A pressure tank is filled with organic material and water. Steam is released into the bottom of the tank and raises the temperature to the desired level. Once the desired process time is over, the bottom valve is opened and the processed mass is discharged. The advantage of this technique is that the equipment is simple, but there are problems in achievin
REFERENCES:
patent: 3920506 (1975-11-01), Morgan
patent: 4229296 (1980-10-01), Wheaton et al.
patent: 4753787 (1988-06-01), Krijgsman
patent: 4876802 (1989-10-01), Gergely et al.
patent: 4912078 (1990-03-01), Krijgsman
patent: 4983374 (1991-01-01), Krijgsman
patent: 4992105 (1991-02-01), Werner et al.
patent: 5008375 (1991-04-01), Folbol et al.
patent: 5026527 (1991-06-01), Krijgsman
patent: 5033370 (1991-07-01), Fosbol et al.
patent: 5540847 (1996-07-01), Stultz et al.
Bell Mark L.
Cambi AS
Hailey Patricia L.
Miller Austin R.
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