# US 11,896,946 B2 · Device and method for increasing solid holdup in reaction crystallizer

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- Number: US 11,896,946 B2
- Document ID: US11896946B2
- Status: Granted
- Kind: B2
- Application number: 17/051,735
- Filed: 2020-07-07
- Published: 2021-07-22
- Granted: 2024-02-13
- Earliest claimed: 2019-09-11
- Assignees: Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences & Institute of Process Engineering, Chinese Academy of Sciences
- Applicants: Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences; Institute of Process Engineering, Chinese Academy of Sciences
- Inventors: Quanhong Zhu; Qingshan Huang; Hang Xiao; Chao Yang
- Web page: https://patentgrep.com/patent/US11896946B2

## CPC

- B01J 19/06: Solidifying liquids (making microcapsules B01J13/02)
- B01D 9/0059: {General arrangements of crystallisation plant, e.g. flow sheets}
- B01D 9/0063: {Control or regulation (control per se G05)}
- B01D 2009/0086: {Processes or apparatus therefor}
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)

## Abstract

A device and method for increasing solid holdup in a reaction crystallizer are disclosed. The device includes a discharge pipe, a clear liquid pipe, a clear liquid tank and a gas collecting pipe. A lower end of the discharge pipe is inserted into the crystallizer below the liquid level, while that of the clear liquid pipe is inserted into the clear liquid tank below the liquid level. By using the gas collecting pipe, the reaction crystallizer and the clear liquid tank are communicated all the time. When feeding, a liquid-solid mixture in the crystallizer automatically enters the discharge pipe and flows upward slowly therein, during which solid particles gradually settle down and automatically fall back into the crystallizer while the clear liquid keeps on flowing upward, enters the clear liquid pipe and thereby flows into the clear liquid tank. The clear liquid tank maintains a constant liquid level via overflowing.

## Claims

### Claim 1

A device for increasing solid holdup in a reaction crystallizer, comprising:
a reaction crystallizer;
a clear liquid tank;
a discharge pipe having a discharge pipe first end;
wherein discharge pipe first end resides in the reaction crystallizer;
a clear liquid pipe having a clear liquid pipe first end and a clear liquid pipe second end;
wherein the clear liquid pipe first end resides in the clear liquid tank;
wherein the clear liquid pipe second end connects to the discharge pipe at a first pipe junction at a first pipe junction height, thereby allowing fluid to flow between the discharge pipe and the clear liquid pipe;
a gas collecting pipe having a gas collecting pipe lower end and a gas collecting pipe intermediate region at a gas collecting pipe intermediate region height;
wherein gas collecting pipe lower end communicates with the discharge pipe;
wherein the gas collecting pipe intermediate region height is above the first pipe junction height; and
whereby, when a level of liquid residing in the reaction crystallizer is above the discharge pipe first end, a level of liquid in the clear liquid tank is above a level of the clear liquid pipe first end, and fluid fills the gas collecting pipe intermediate region, then the level of liquid residing in the reaction crystallizer and the level of liquid in the clear liquid tank attain the same level.

### Claim 2 (depends on 1)

The device of claim 1, wherein an inverted cone-shaped expansion segment is disposed on an upper portion of the discharge pipe to reduce a liquid velocity and improve liquid-solid separation efficiency; and
wherein a cone angle of the inverted cone-shaped segment is greater than a reposing angle of crystal particles to prevent blockage by accumulation.

### Claim 3 (depends on 1)

The device of claim 1, wherein the gas collecting pipe has a second end that connects to an input of an exhaust pump.

### Claim 4

A method for increasing solid holdup, in an apparatus comprising a reaction crystallizer;
a clear liquid tank;
a discharge pipe having a discharge pipe first end;
wherein discharge pipe first end resides in the reaction crystallizer;
a clear liquid pipe having a clear liquid pipe first end and a clear liquid pipe second end;
wherein the clear liquid pipe first end resides in the clear liquid tank;
wherein the clear liquid pipe second end connects to the discharge pipe at a first pipe junction at a first pipe junction height, thereby allowing fluid to flow between the discharge pipe and the clear liquid pipe;
a gas collecting pipe having a gas collecting pipe lower end and a gas collecting pipe intermediate region at a gas collecting pipe intermediate region height;
wherein gas collecting pipe lower end communicates with the discharge pipe;
wherein the gas collecting pipe intermediate region height is above the first pipe junction height; and whereby, when a level of liquid residing in the reaction crystallizer is above the discharge pipe first end, a level of liquid in the clear liquid tank is above a level of the clear liquid pipe first end, and fluid fills the gas collecting pipe intermediate region, then the level of liquid residing in the reaction crystallizer and the level of liquid in the clear liquid tank attain the same level, the method comprising:
adding a clear liquid to the clear liquid tank, so that the clear liquid pipe first end is submerged;
adding liquid to the reaction crystallizer, so that the discharge pipe first end is submerged;
exhausting gas from the gas collecting pipe, thereby sucking liquid up into the discharge pipe and sucking liquid up into the clear liquid pipe until the reaction crystallizer and the clear liquid tank are in liquid communication with one another; and
pumping a feedstock solution into the reaction crystallizer, thereby resulting in flow into the discharge pipe and from the discharge pipe through the clear liquid pipe into the clear liquid tank.

### Claim 5 (depends on 4)

The method of claim 4, wherein the clear liquid tank comprises an overflow port, and continuing pumping the feedstock solution into the reaction crystallizer until after the level of liquid in the clear liquid tank reaches the level of the overflow port.

### Claim 6 (depends on 4)

The method of claim 4, further comprising configuring an automatic control system to control the liquid level in the gas collecting pipe so that the liquid level in the gas collecting pipe remains above a level at which the reaction crystallizer and the clear liquid tank remain in liquid communication with one another.

### Claim 7 (depends on 4)

The method of claim 4, further comprising configuring the gas collecting pipe to have an expansion segment, and configuring an automatic control system to control the liquid level in the gas collecting pipe so that the liquid level remains in the expansion segment.

### Claim 8 (depends on 7)

The method of claim 7 further comprising configuring the gas collecting pipe to have an expansion segment providing a valve above the expansion segment.