JP3236936U - Pulp liquid evaporation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulp liquid evaporation system for reducing scale formation of an evaporator. SOLUTION: A pulp liquid concentrating system 200 has a plurality of evaporators 201a to 201f arranged in series, and a pipe at an inlet of the evaporator 201a which is operated at the highest temperature among the plurality of evaporators. Includes at least one transducer 204a positioned on the outer surface of the [Selection diagram] Fig. 2

Description

The present invention relates to a pulp liquid evaporation system, particularly a pulp liquid evaporation system that reduces the scale formation of an evaporator in a pulp liquid evaporation system.

Traditionally, evaporators burn pulp liquor, such as black liquor and red liquor, from 15% by weight of dry solids left in the pulp wash in a recovery boiler. It has been used to evaporate to 70-85% by weight of dry solids before being made. As the percentage of dry solids increases, the volatile compound is released from the pulp liquor and separated from the condensate, after which the condensate is collected for further use. This maximizes the reuse of the condensate.

When evaporation occurs, the volatile components from the pulp liquor are released with the evaporated water as part of the increase in the proportion of dry solids. However, the formation of solid matter from dissolved or ionic matter often forms a scale inside the evaporator. Scaling then reduces the effectiveness of the evaporation process. This requires mechanical or chemical cleaning of the evaporator.

Therefore, there is a need to develop a pulp liquid evaporation system that reduces scale formation.

The present invention is provided when one or more transducers are provided in the inlet tube of the pulp liquid evaporator, which are designed to emit a mechanical wave toward the pulp liquid flowing in the evaporator. It is based on the observation that the scale of the evaporator can be reduced.

Therefore, according to the first aspect of the present invention, in the pulp liquid concentration system (100, 200), one or more having a pulp liquid inlet (102, 202) and a product liquid outlet (103, 203). It comprises an evaporator (101, 201a-201f) and one or more transducers (104, 204) positioned on the outer surface of the inlet, the one or more transducers operating the pulp enrichment system. Provided is a pulp liquor concentrating system that sometimes emits mechanical waves towards the pulp liquor inside the inlet.

According to the second aspect of the present invention, in the first aspect, at least one of the one or more transducers directs at least a part of the mechanical wave to the inside of the structure of the evaporator. It has become.

According to the third aspect of the present invention, in the first or second aspect, the pulp liquid concentrating system provides a tightening means for fixing and fastening the one or more transducers to the outer surface of the inlet. Equipped.

According to the fourth aspect of the present invention, in any one of the first to third aspects, the one or more evaporators are a rising film evaporator, a falling film evaporator, a direct contact. It is selected from the group consisting of evaporators, forced circulation evaporators, tubular evaporators, lamella evaporators, and plate & shell evaporators.

According to the fifth aspect of the present invention, in any one of the first to fourth aspects, the pulp liquid concentrating system comprises a plurality of evaporators (201a to 201f) arranged in series, and the pulp. The liquid concentration system has at least one of the above-mentioned evaporators (203) positioned on the outer surface of the tube at the inlet (202) of the evaporator (201a) which is operated at the maximum temperature. Evaporate.

Typical non-limiting embodiments of the present invention with respect to both structure and method of operation are best understood by reference to the accompanying drawings with specific exemplary embodiments, along with additional objectives and advantages. To.

As used herein, the verbs "equipped" and "included" do not preclude or require the existence of features not listed, but are used as a broad limitation. The features described in the accompanying claims may be freely combined with each other, except as explicitly stated. Furthermore, the use of singular forms such as "a" and "an" throughout the specification does not preclude its meaning as plural.

Further, in the present specification, the terms acoustic, electrodynamics, and ultrasonic waves are used as synonyms.

Exemplary limited and internal embodiments of the present invention and their advantages are described in detail below with reference to the accompanying drawings.

It is a schematic diagram which shows the pulp liquid evaporation system based on the typical non-limiting embodiment of this invention. It is another figure which shows the pulp liquid evaporation system based on the typical non-limiting embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. A common reference code is attached to the corresponding components throughout the drawings.
FIG. 1 is a schematic diagram showing a pulp liquid evaporation system 100 that evaporates a pulp liquid, for example, a black liquid or a red liquid. The pulp liquid evaporation system 100 includes one evaporator 101 having an inlet 102 and an outlet 103, and a transducer 104 positioned on the outer surface of the inlet 102. The pulp liquid evaporation system 100 preferably includes a tightening means for fixing and fastening the transducer to the outer surface of the inlet 102.

The transducer 104 is adapted to emit a mechanical wave inside the tube at the inlet 102. A particularly suitable mechanical wave is an ultrasonic wave with a frequency of 20 kHz to 2 GHz (ca 20 kHz-2 GHz). During operation of the pulp liquid evaporation system 100, mechanical waves are directed towards the pulp liquid flowing through the tube at the inlet of the evaporator.

For example, the following effects can help prolong the cleaning cycle of the evaporator.
-Mechanical waves divide large polluted particles in a stream into smaller pieces. Small particles do not tend to adhere to the inner surface of the evaporator.
-Mechanical waves assist in crystallization in the flow of pulp liquor. The crystals flow through the evaporator without adhering to the inner surface of the evaporator.
-Mechanical waves mix the liquid and make the chemical process more efficient.

A typical pulp liquid evaporator consists of a heat exchanger and a gas-liquid separation container. The evaporator can be any evaporator suitable for evaporating pulp liquors such as red liquor and black liquor. Exemplary non-limiting suitable evaporators are ascending membrane evaporators, falling membrane evaporators, direct contact evaporators, forced circulation evaporators, tubular evaporators, thin plate evaporators, and plate & shell evaporators.

According to an exemplary embodiment, the one or more transducers are ultrasonic Langevin transducers adapted to be electrically and physically impedance matched to the outer surface of the inlet tube. Particular attention has been paid to allowing transmission of sufficiently wideband transmission signals so that efficient coded waveforms can be used. This can be done by using wideband electrical and mechanical matching techniques known in the art. For example, an impedance matching LC circuit is designed to have a resonance that is slightly higher than the resonance of the connected transducer. This allows for sufficient bandwidth for the coded waveform (eg, 1-50% bandwidth relative to the center frequency) and high ultrasonic output (> 1 W / cm2) at the same time.

According to a preferred embodiment, the pulp liquid evaporation system 100 includes a transducer configured to direct at least a portion of the mechanical waves into the evaporator structure.

FIG. 2 shows another exemplary pulp liquid evaporation system 200 of the present invention. The pulp liquid evaporation system 200 includes six rising membrane evaporators 201a-201f in series. In this type of pulp liquid evaporation system 200, especially the evaporator operating at the highest temperature tends to be contaminated depending on the scale. Therefore, it is preferred that at least one transducer 204 be positioned on the outer surface of the inlet 202 of the evaporator 201a operating at maximum temperature. The pulp liquid evaporation system 200 also comprises an outlet 203, a concentrator 205, and a vapor circulation system 206.

Example 1 Example 1
The black liquor evaporation system consists of six evaporators in series. The two hottest evaporators need to be mechanically cleaned 20 times a year.
Transducers were installed at the inlets of the two hottest evaporators, and when the black liquor flowing from the inlets to the evaporators was exposed to ultrasonic waves, the need for mechanical cleaning was reduced by more than 75% per year. Due to the improved heat transfer of the evaporator, the improvement in pump efficiency per unit was more than 10%.

Example 2

The red liquid evaporation system consists of a single evaporator. If the evaporator inlet is equipped with a transducer and the red liquid flowing from the inlet to the evaporator is exposed to ultrasonic waves, the increase during the mechanical cleaning of the evaporator will increase by more than 60% and the energy efficiency will be 50%. As described above, the heat transfer coefficient was increased by 40% or more, the evaporation rate was increased by 6% or more, and the operating time was increased by 25%.

Although the embodiments of the present invention have been described above, it will be understood by those skilled in the art that various modifications and changes can be made without departing from the disclosure scope of the claims described later.

100, 200 Pulp liquid evaporation system 101, 201a-201f Evaporator 102, 202 Inlet 103, 203 Outlet 104, 204, 204a, 204b Transducer 205 Concentrator 206 Vapor circulation system

Claims (5)

In the pulp liquid concentration system (100, 200)
With one or more evaporators (101, 201a-201f) having pulp liquor inlets (102, 202) and product liquor outlets (103, 203).
Equipped with one or more transducers (104, 204) positioned on the outer surface of the inlet, the one or more transducers towards the pulp liquid inside the inlet during operation of the pulp enrichment system. A pulp liquid concentration system that emits mechanical waves. The pulp liquid concentration system according to claim 1, wherein at least one of the one or the plurality of transducers directs at least a part of the mechanical wave to the inside of the structure of the evaporator. The pulp liquid concentrating system according to claim 1 or 2, wherein the pulp liquid concentrating system comprises a tightening means for fixing and fastening the one or a plurality of transducers to the outer surface of the inlet. The one or more evaporators are selected from the group consisting of ascending membrane evaporators, falling membrane evaporators, direct contact evaporators, forced circulation evaporators, tubular evaporators, thin plate evaporators, and plate & shell evaporators. The pulp liquid concentration system according to any one of claims 1 to 3. The pulp liquid concentrating system includes a plurality of evaporators (201a to 201f) arranged in series.
The pulp liquid concentrating system is at least one of the plurality of evaporators (203) positioned on the outer surface of the tube at the inlet (202) of the evaporator (201a) which is operated at the maximum temperature. ), The pulp liquid concentration system according to any one of claims 1 to 4.

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