Method for syngas clean-up of semi-volatile organic compounds with solids removal

Patent metadata

Field	Value
Publication number	US-10065858-B2
Application number	US-201715430633-A
Country	US
Kind code	B2
Filing date	Feb 13, 2017
Priority date	Sep 27, 2011
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

A system and method for processing unconditioned syngas first removes solids and semi-volatile organic compounds (SVOC), then removes volatile organic compounds (VOC), and then removes at least one sulfur containing compound from the syngas. Additional processing may be performed depending on such factors as the source of syngas being processed, the products, byproducts and intermediate products desired to be formed, captured or recycled and environmental considerations.

First claim

What is claimed is:

1. A method for cleaning unconditioned syngas for introduction into a syngas processing technology application, the unconditioned syngas including semi-volatile organic compounds (SVOC), and at least one or both of hydrogen chloride and hydrogen sulfide, the method comprising:
(a) contacting the unconditioned syngas with water to reduce the temperature of the syngas to below the SVOC condensation temperature to thereby form an intermediate SVOC-depleted syngas containing steam, and a first mixture comprising SVOC, solids and water;
(b) removing steam from the intermediate SVOC-depleted syngas containing steam to form: (i) a first depleted syngas stream which has a reduced amount of SVOC and solids relative to the unconditioned gas, and (ii) a second mixture comprising SVOC, solids and water;
(c) after step (b), removing hydrogen chloride and/or hydrogen sulfide from the first depleted syngas stream with a scrubber;
(d) after step (c), compressing the syngas to a pressure ranging from 100 PSIG to 2,000 PSIG;
(e) after step (d), removing at least one sulfur containing compound from the syngas;
(f) also after step (b), separating the water within the second mixture based upon immiscibility so that the SVOC and solids collect together to form a third mixture separate from the water; and
(g) after step (f) agglomerating the solids together to form an agglomerated cake having density greater than that of water;
wherein:
(i) the hydrogen chloride concentration in unconditioned syngas ranges from greater than 0 ppm to less than or equal to 1000 ppm;
(ii) the hydrogen chloride capture efficiency is greater than 80%;
(iii) the hydrogen sulfide concentration in unconditioned syngas ranges from greater than 0 ppm to less than or equal to 1000 ppm; and
(iv) the hydrogen sulfide capture efficiency is greater than 80%.

2. The method of claim 1 , wherein:
the unconditioned syngas has a metal concentration greater than 0 ppm and less than or equal to 30 ppm, said metal being one or more from the group consisting of mercury, arsenic, lead, and cadmium; and the method further comprises:
after step (d) and before step (e), removing at least a portion of said metal such that the metal concentration is less than or equal to 10 ppb.

3. The method of claim 2 , comprising:
removing said metal with a cylindrical pressure vessel containing one or more from the group consisting of cellulose acetate, cellulose acetate packing, cellulose acetate beads, cellulose acetate spheres, cellulose acetate flake, cellulose acetate pellets, and sorbents.

4. The method of claim 1 , wherein:
the unconditioned syngas has a carbonyl sulfide concentration greater than 0 ppm and less than or equal to 15 ppm; and the method further comprises:
in step (e), removing at least a portion of said carbonyl sulfide such that its concentration is less than or equal to 30 ppb.

5. The method of claim 4 , comprising:
injecting water into a packed hydrolysis bed containing alumina media, to hydrolyze and convert the carbonyl sulfide into carbon dioxide and hydrogen sulfide.

6. The method of claim 4 , comprising,
removing the carbonyl sulfide with a cylindrical pressure vessel containing one or more from the group consisting of packed bed media, packed alumina bed media, packed titania bed media, alumina, titania, alumina beads, alumina pellets, alumina granules, alumina spheres, alumina packing, titania beads, titania pellets, titania granules, titania spheres, and titania packing.

7. The method of claim 1 , comprising, in step (d):
compressing syngas with a syngas compressor from a first pressure ranging from 15 PSIG to 50 PSIG to a second higher pressure ranging from 100 PSIG to 2,000 PSIG.

8. The method of claim 7 , comprising:
introducing a gaseous hydrocarbon source to the inlet of the syngas compressor, said gaseous hydrocarbon including one or more from the group consisting of natural gas, syngas, refinery offgases, naphtha, methanol, ethanol, petroleum, methane, ethane, propane, butane, hexane, benzene, toluene, xylene, and naphthalene.

9. The method of claim 1 , wherein:
the unconditioned syngas has an ammonia concentration greater than 0 ppm and less than or equal to 1000 ppm; and the method further comprises:
after step (d) and before step (e), removing at least a portion of the ammonia with a capture efficiency greater than 80%.

10. The method of claim 9 , comprising removing ammonia with water in a scrubber.

11. The method of claim 10 , wherein:
after removing ammonia with water in a scrubber, the syngas has a residual ammonia concentration greater than 0 ppm and less than or equal to 15 ppm; and the method further comprises:
polishing ammonia in a fixed bed adsorber such that the ammonia concentration is reduced to less than or equal to 10 ppb.

12. The method of claim 11 , wherein:
the fixed bed adsorber comprises a cylindrical pressure vessel containing one or more from the group consisting of sorbents, molecular sieve type 4A, 5A sorbents, 13× sorbents, dealuminated faujasite, dealuminated pentasil, and clinoptilolite.

13. The method of claim 1 , comprising:
(e1) after step (e), removing sulfur with a fixed bed adsorber to reduce sulfur concentration to less than 30 ppb.

14. The method of claim 13 , comprising:
removing at least one sulfur containing compound with a cylindrical pressure vessel containing one or more from the group consisting of sorbent media, zinc oxide sorbent media, zinc oxide beads, zinc oxide pellets, zinc oxide granules, zinc oxide spheres, and zinc oxide packing.

15. The method of claim 1 , comprising:
(h), after step (g), steam methane reforming to form hydrogen and carbon monoxide within a steam methane reformer.

16. The method of claim 15 , wherein:
the steam methane reformer accepts an inlet gaseous hydrocarbon concentration ranges from 1 wt % to 100 wt %; and
the steam methane reformer operates at a conversion efficiency ranging from 50% to 100%.

17. The method of claim 15 , wherein:
the steam methane reformer accepts an inlet SVOC concentration greater than 0 ppm; and
the steam methane reformer operates at a conversion efficiency greater than 50%.

18. The method of claim 15 , wherein:
the steam methane reformer accepts an inlet volatile organic compound (VOC) concentration greater than 0 ppm; and
the steam methane reformer operates at a conversion efficiency greater than 50%.

19. The method of claim 1 , comprising:
in step (c), introducing the first depleted syngas stream into a scrubber; and
removing hydrogen chloride from the first depleted syngas stream, using water as the main scrubbing absorption liquid in said scrubber.

20. The method of claim 19 , comprising:
condensing residual steam contained within the syngas to provide at least a portion of said water as the main scrubbing absorption liquid.

21. The method of claim 19 , wherein:
the scrubber comprises a pressure vessel having a lower section, an upper section, and a central section located between the upper and lower sections, the central section containing packing; and the method comprises:
introducing water into the packing of the central section; and
introducing the first depleted syngas stream into the lower section of the scrubber so that the first depleted syngas stream passes up through the central section and comes into intimate contact with the water traveling countercurrently via gravity flow down through the packing.

22. The m

Assignees

• Thermochem Recovery Int Inc

Inventors

• Chandran Ravi
• Leo Daniel Michael
• Freitas Shawn Robert
• Newport Dave G
• Whitney Hamilton Sean Michael
• Burciaga Daniel A

Classifications

• C01B3/38

  using catalysts · CPC title

• C01B2203/04

  containing a purification step for the hydrogen or the synthesis gas · CPC title

• C01B2203/0475

  the impurity being carbon dioxide · CPC title

• C01B2203/0415

  Purification by absorption in liquids · CPC title

• C01B2203/042

  Purification by adsorption on solids · CPC title