# US 5,700,432 A · Fluidized-bed reactor and a temperature-controlling method for the fluidized-bed reactor

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- Number: US 5,700,432 A
- Document ID: US5700432A
- Status: Granted
- Kind: A
- Application number: 08/532,649
- Filed: 1995-12-15
- Granted: 1997-12-23
- Earliest claimed: 1994-02-08
- Assignees: Mitsubishi Chemical Corporation
- Inventors: Minoru Tanaka; Chi Wai Hui
- Web page: https://patentgrep.com/patent/US5700432A

## CPC

- B01J 8/1809: {Controlling processes}
- B01J 8/1836: {Heating and cooling the reactor (B01J8/42 takes precedence)}
- B01J 2208/00044: Temperature measurement
- B01J 2208/00141: Coils
- B01J 2219/185: vertical
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

A fluidized-bed reactor has a plurality of heat-removing pipes and at least one temperature detection section disposed in a fluidized-bed forming portion. The heat-removing pipes are connected with coolant-feeding pipes and coolant-draining pipes at the outside of the reactor at least one of the heat-removing pipes is supplied with a first coolant at a stationary velocity and at least one of the other heat-removing pipes is supplied with a second coolant at a variable velocity. A temperature controlling method is disclosed for a fluidized-bed reactor in which heat is removed by using these heat-removing pipes in the fluidized-bed reactor.

## Claims

### Claim 1

A temperature-controlling method for a fluidized-bed reactor for conducting an exothermic gas phase reaction for obtaining malic anhydride from butane in the fluidized-bed reactor, the fluidized-bed reactor having a plurality of heat-removing pipes disposed in the fluidized-bed, the method comprising:
supplying a first coolant at a stationary velocity to at least one of the heat removing pipes,
simultaneously supplying a second coolant at a variable velocity to at least one of the other heat-removing pipes, the second coolant being a gas,
removing not less than 50% of the total amount of heat to be removed utilizing the latent heat of vaporization of the first coolant,
feeding the second coolant at the variable velocity depending on a temperature detected by a temperature detection section in the fluidized-bed,
providing a catalyst having a weight-average particle diameter of from 30 to 100 .mu.m, containing 20 to 70% by weight of a fine powder with a particle diameter of not more than 44 .mu.m and having a particle density of not more than 3000 kg/m.sup.3, and
fluidizing the catalyst by introducing a gas from a lower portion of the fluidized-bed reactor.

### Claim 2 (depends on 1)

A temperature-controlling method for a fluidized-bed reactor as defined in claim 1, wherein water is supplied as the coolants to the heat-removing pipe to which the coolants are supplied at the stationary velocity.

### Claim 3 (depends on 1)

The temperature controlling method for a fluidized-bed reactor as defined in claim 1 wherein water is supplied as the first coolant.

### Claim 4 (depends on 1)

A temperature-controlling method for a fluidized-bed reactor as defined in claim 1, wherein the first coolant is heated water.

### Claim 5 (depends on 1)

The temperature controlling method for a fluidized-bed reactor as defined in claim 1 wherein the second coolant is steam.

### Claim 6 (depends on 1)

A temperature-controlling method as defined in claim 1, wherein the amount of heat to be removed in the heat-removing pipe to which the first coolant is supplied at the stationary velocity is not less than 80% of the total amount of heat to be removed.

### Claim 7 (depends on 1)

A temperature-controlling method as defined in claim 1, wherein the feeding rate of the reaction material to the fluidized-bed reactor is maintained within a constant range.

### Claim 8 (depends on 1)

A temperature-controlling method as defined in claim 1, wherein the total amount of heat to be removed is from 10,000 to 200,000 kcal/m.sup.2.

### Claim 9 (depends on 1)

A temperature-controlling method for a fluidized-bed reactor as defined in claim 1, wherein the gas velocity for maintaining the catalyst in the fluidizing condition is maintained at 35 to 80 cm/sec based on the effective cross sectional area of the reactor.

### Claim 10 (depends on 1)

The temperature controlling method as defined in claim 1 further comprising controlling the feeding velocity of the second coolant to the heat removal pipe by bypassing a controlled portion of the second coolant through a bypass pipe connecting coolant supply pipes and coolant draining pipes.

### Claim 11 (depends on 10)

The temperature control method of claim 10 further comprising providing a control valve for controlling the portion of the second coolant which bypasses the heat removal pipe.