Thermal decomposition of magnesium chloride

Patent metadata

Field	Value
Publication number	US-2020032300-A1
Application number	US-201916590422-A
Country	US
Kind code	A1
Filing date	Oct 2, 2019
Priority date	Apr 1, 2014
Publication date	Jan 30, 2020
Grant date	—

Abstract

A method for conversion of magnesium chloride into magnesium oxide and HCl includes the steps of providing a magnesium chloride compound to a thermohydrolysis reactor, the reactor being at a temperature of at least 300° C., withdrawing MgO from the thermohydrolysis reactor in solid form, and withdrawing an HCl containing gas stream from the thermohydrolysis reactor. The magnesium chloride compound provided to the thermohydrolysis reactor may be a solid magnesium chloride compound which comprises at least 60 wt. % of MgCl2.4H2O.

First claim

1 . Method for conversion of magnesium chloride into magnesium oxide and HCl, said method comprising the steps of:
providing a magnesium chloride compound to a thermohydrolysis reactor, the reactor being at a temperature of at least 300° C.; and, withdrawing MgO from the thermohydrolysis reactor in solid form, and withdrawing an HCl containing gas stream from the thermohydrolysis reactor, wherein the magnesium chloride compound provided to the thermohydrolysis reactor is a solid magnesium chloride compound which comprises at least 60 wt. % of MgCl 2 .4H 2 O.

2 . The method according to claim 1 , wherein at least 80 wt. % of the magnesium chloride compound is MgCl 2 .4H 2 O.

3 . The method according to claim 1 , wherein the magnesium chloride compound comprises less than 30 wt. % of magnesium chloride hexahydrate.

4 . The method according to claim 1 , wherein the magnesium chloride compound comprises less than 40 wt. % of the total of magnesium chloride anhydrate, magnesium chloride monohydrate and magnesium chloride dihydrate.

5 . The method according to claim 4 , wherein the magnesium chloride compound comprises less than 30 wt. % of the total of magnesium chloride anhydrate, magnesium chloride monohydrate and magnesium chloride dihydrate.

6 . The method according to claim 1 , wherein the magnesium chloride compound comprises less than 30 wt. % of magnesium chloride hexahydrate and less than 40 wt. % of the total of magnesium chloride anhydrate, magnesium chloride monohydrate and magnesium chloride dihydrate.

7 . The method according to claim 1 , said magnesium chloride compound comprising at least 60 wt. % of MgCl 2 .4H 2 O is obtained by subjecting a magnesium chloride solution to a drying step at a temperature of 100-160° C.

8 . The method according to claim 1 , wherein the thermohydrolysis reactor is at a temperature below 800° C.

9 . The method according to claim 1 , wherein the thermohydrolysis is carried out in the presence of a gas stream.

10 . The method according to claim 9 , wherein the gas stream provides heat to the thermohydrolysis reactor and carries HCl from the thermohydrolysis reactor.

11 . The method according to claim 1 , wherein the thermohydrolysis reactor is a tube reactor wherein the magnesium chloride compound enters the reactor at or near one end of the reactor, further indicated as the feed end, and product magnesium oxide is withdrawn at or near the other end of the reactor, further indicated as the product end, while a gas stream enters the reactor at or near the product end, and a gas stream comprising HCl is withdrawn at or near the feed end.

12 . A method for conversion of magnesium chloride into magnesium oxide and HCl, said method comprising the steps of:
a) subjecting a magnesium chloride solution to a drying step at a temperature of 100-150° C. to form a magnesium chloride compound comprising at least 50 wt. % of MgCl 2 .4H 2 O; b) providing said magnesium chloride compound to a thermohydrolysis reactor, the reactor being at a temperature of at least 300° C.; and, c) withdrawing MgO from the thermohydrolysis reactor in solid form, and withdrawing an HCl containing gas stream from the thermohydrolysis reactor, wherein the drying step a) is carried out in the presence of HCl.

13 . The method according to claim 12 , wherein said drying step a) forms a magnesium chloride compound comprising at least 60 wt. % of MgCl 2 .4H 2 O.

14 . The method according to claim 12 , wherein said drying step a) forms a magnesium chloride compound comprising less than 40 wt. % of the total of magnesium chloride anhydrite, magnesium chloride monohydrate and magnesium chloride dihydrate.

15 . The method according to claim 12 , wherein the drying step a) is carried out at a temperature of 110-160° C.

16 . The method according to claim 12 , wherein the HCl present in the drying step a) is provided by providing the HCl-containing gas stream derived from the thermohydrolysis reactor to the drying step.

17 . The method according to claim 12 , wherein the drying step a) is performed by spray-drying.

18 . The method according to claim 12 , wherein the thermohydrolysis is carried out in the presence of a gas stream.

19 . The method according to claim 12 , wherein the gas stream provides heat to the thermohydrolysis reactor and carries HCl from the thermohydrolysis reactor.

20 . The method according to claim 12 further comprising the steps of
subjecting a carbon source to a fermentation step to form a carboxylic acid, which fermentation step comprises the steps of fermenting a carbon source by means of a micro-organism in a fermentation broth to form carboxylic acid and neutralizing at least part of the carboxylic acid by adding a magnesium base selected from magnesium oxide and magnesium hydroxide, thereby obtaining a magnesium carboxylate;
subjecting the magnesium carboxylate to an acidification step wherein the magnesium carboxylate contacted with HCl in an aqueous environment to form an aqueous mixture comprising carboxylic acid and magnesium chloride; and,
subjecting the aqueous mixture comprising carboxylic acid and magnesium chloride to a separation step, to form an effluent comprising carboxylic acid and a magnesium chloride solution, said magnesium chloride solution being provided to drying step a).

21 . The method according to claim 20 comprising the step of recycling the magnesium oxide withdrawn from the thermohydrolysis reactor at least in part to the fermentation step.

22 . A method for conversion of magnesium chloride into magnesium oxide and HCl, said method comprising the steps of:
a) subjecting a magnesium chloride solution to a drying step at a temperature of 100-160° C. to form a magnesium chloride compound comprising at least 50 wt. % of MgCl 2 .4H 2 O; b) providing said magnesium chloride compound to a thermohydrolysis reactor, the reactor being at a temperature of at least 300° C.; and, c) withdrawing MgO from the thermohydrolysis reactor in solid form, and withdrawing an HCl containing gas stream from the thermohydrolysis reactor, wherein the drying step a) is performed by spray-drying.

23 . The method according to claim 22 , wherein said drying step a) forms a magnesium chloride compound comprising at least 60 wt. % of MgCl 2 .4H 2 O.

24 . The method according to claim 22 , wherein said drying step a) forms a magnesium chloride compound comprising less than 40 wt. % of the total of magnesium chloride anhydrate, magnesium chloride monohydrate and magnesium chloride dihydrate.

25 . The method according to claim 22 , wherein the drying step a) is carried out at a temperature of 110-160° C.

26 . The method according to claim 22 , wherein the drying step a) is carried out at a temperature of 120-160° C.

27 . The method according to claim 22 , wherein the thermohydrolysis is carried out in the presence of a gas stream.

28 . The method according to claim 22 , wherein the gas stream provides heat to the thermohydrolysis reactor and carries HCl from the thermohydrolysis reactor.

29 . The method according to claim 22 further comprising the steps of:
subjecting a carbon source to a fermentation step to form a carboxylic acid, which fermentation step comprises the steps of fermenting a carbon source by means of a micro-organism in a fermentation broth to form carboxyl

Assignees

• Purac Biochem Bv

Inventors

• De Haan André Banier
• Bokhove Jeroen
• Laksmana Fesia Lestari

Classifications

• C01B7/035

  Preparation of hydrogen chloride from chlorides · CPC title

• C01F5/10 Primary

  by thermal decomposition of magnesium chloride with water vapour · CPC title

• B01J8/067

  Heating or cooling the reactor (B01J8/062 takes precedence) · CPC title

• C12P7/40 Primary

  containing a carboxyl group {including Peroxycarboxylic acids} · CPC title

• Y02P20/582

  Recycling of unreacted starting or intermediate materials · CPC title