Method and device for the hydrolysis of liquid, organic substrates

Abstract

In a method for the hydrolysis of liquid, organic substrates (1), the substrate to be hydrolysed is introduced into a circulation loop for heating, where an equal amount of hydrolysed substrate (1) is displaced from the circulation loop (6, 7, 8, 9). An appropriate system can have a circulation loop, a feed device, a circulation pump for generating a circulation flow in the circulation loop, and a heater for heating and reheating the circulation flow.

Claims

1. Method for a hydrolysis of liquid, organic substrates, wherein a substrate to be hydrolysed is introduced into a circulation loop for heating and wherein an equal amount of hydrolysed substrate is displaced from said circulation loop.

2. Method according to claim 1, wherein said introduced substrate is mixed with a chemical in order to change its pH value to increase an effect of said hydrolysis.

3. Method according to claim 2, wherein said introduced substrate is mixed with caustic solution in order to increase said pH value, to increase an effect of said hydrolysis, and to at least partially re-neutralize said caustic solution by means of organic acids released in said process.

4. Method according to claim 1, wherein a dwell time of said substrate in said circulation loop is increased by an additional volume in said circulation.

5. Method according to claim 4, wherein a volume flow of said circulation and a volume flow of a discharging substrate leave a volume in said circulation through different outlets.

6. Method according to claim 4, wherein said additional volume is formed by internal fittings so as to avoid a complete mixing, where said discharging substrate has a different dwell time compared with a circulation flow.

7. Method according to claim 6, wherein said dwell time of said discharging volume flow of said substrate is greater than said dwell time of said circulation flow.

8. Method according to claim 1, wherein said substrate is fed into a circulation flow upstream of a heater.

9. Method according to claim 8, wherein said substrate is fed into said circulation flow upstream of a circulation pump.

10. Device for the hydrolysis of liquid, organic substrates for carrying out the method according to claim 1, having: a circulation loop, a feed device, a circulation pump for generating a circulation flow in said circulation loop, a heater for heating and reheating said circulation flow.

11. Device according to claim 10, wherein said heater is designed as a heat exchanger for heating and reheating said circulation flow.

12. Device according to claim 10, wherein an intermediate container is provided in said circulation loop as an additional volume for increasing a dwell time of said substrate in said device.

13. Device according to claim 10, wherein a feeding of said substrate into said circulation flow upstream of said heater is provided.

14. Device according to claim 13, wherein a feeding of said substrate into said circulation flow is provided downstream of the circulation pump.

15. Device according to claim 10, wherein a feeding-in of said substrate is provided on a suction side of said circulation pump.

16. Device according to claim 10, wherein internal fittings are provided in said circulation loop, so that a ratio of dwell times of said circulating substrate to discharging substrate is different.

17. Device according to claim 16, wherein internal fittings are provided in said circulation loop in said additional volume according to claim 12.

18. Device according to claim 16, wherein said dwell time of said discharging substrate is greater than said dwell time of said circulating substrate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Further advantages and aspects of the invention can be seen from the claims and from the following description of preferred exemplary embodiments of the invention which are explained below with reference to the figures. In the drawings:

[0028] FIGS. 1 to 5 show exemplary methods for a treatment in accordance with the invention for hydrolysing organic substrates or in organic substrates.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] While the invention will be described in connection with one or more preferred embodiments, it will be understood that it is not intended to limit the invention to those embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

[0030] In the method according to FIG. 1, a liquid, organic substrate 1, for example the surplus sludge in a sewage plant, is fed to the system with the aid of a pump 2. If required, the organic substrate is mixed with caustic solution 3. The caustic solution is not absolutely essential but significantly increases the effect of the hydrolysis as explained previously. The substrate 4, which if required is mixed with caustic solution, is mixed 5 in a circulation loop consisting of heat exchanger 6, pump suction line 7, pump 8 and pump pressure line 9. The circulation flow 7 and 9 brought about by the pump 8 is preferably a multiple of the supplied substrate flow 1 so that, because of the lower mixing viscosity, better boundary conditions are created for the heat transfer in the heat exchanger 6 in spite of a poorer temperature gradient.

[0031] Preferably, the circulation flow is heated to a temperature of 30 C. to 180 C., in particular 40 C. to 90 C., preferably 60 C. to 70 C.

[0032] The ratio of the circulation flow to the feed flow can be 1:1 to 10:1, in particular 1:1 to 5:1, preferably 1:1 to 3:1.

[0033] As a result of the continuous feed of the substrate flow 1 to the circulation flow 6 and 8 a hydrolysed volume flow 10 equivalent to the supplied substrate flow 1 is always displaced from the system and fed to the next process step. In contrast to methods previously described, the reactor with its elaborate control system and flow guidance and a separate extraction pump can be dispensed with.

[0034] FIG. 2 shows similar system to that in FIG. 1 with an additional volume 11, as a result of which the dwell time of the substrate 1 in the system can be increased. The additional volume 11 is preferably to be arranged in the position where the discharging, hydrolysed substrate flow 10 is separated out of the system. Preferably, the dwell time of the supplied substrate is arithmetically increased by the additional volume 11 by 5 to 120 minutes, in particular 10 to 60 minutes, preferably 15 to 30 minutes.

[0035] Some positions 12, 13, 14, 15 and 16, in which a volume for increasing the dwell time can likewise be realized, are shown by way of example in FIG. 3. However, if anything, this is for installation reasons.

[0036] FIG. 4 shows a variant based on FIG. 2 in which the supplied substrate 1, if required mixed 4 with caustic solution 3, passes into the circulation loop on the suction side 7 of the circulation pump 8. As a result, an additional mixing of newly fed substrate 1 and circulation loop 7 and 9 or already circulating substrate takes place in the circulation pump 8. Advantageously, the pump 2, which is often present in any case, has practically the same operating data as before the additional installation of the hydrolysis, as virtually the same pressure conditions exist within the circulation loop at point 5 as at the outlet 10 from the circulation.

[0037] Based on FIG. 2, it is of advantage to design the volume 11 such that the dwell time of the already hydrolysed substrate flow 10 is greater than the dwell time of the circulation flow 7 and 9, see FIG. 5. This is achieved in that a partial separation 17 of the volumes occurs within the volume 11, which however the discharging volume flow 10 can negotiate. The separation 17 can be carried out by a baffle or a movable partition inside a stationary container.

[0038] Preferably, the ratio of the dwell time in the volume of circulation flow to discharging volume flow is 1:1 to 1:20, in particular 1:1 to 1:10, preferably 1:1 to 1:3.

[0039] Thus, it is apparent that there has been provided, in accordance with the invention, an invention that fully satisfies the objects, aims and advantages as set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims.