Process for decontaminating syngas

A process for decontaminating syngas, comprising:

• a) contacting syngas with one or more sorbents upstream of one or more catalytic candle filters;
• and
• b) passing the syngas through the catalytic candle filters, the filters containing a mixed catalyst thereby cracking tars to form purified syngas;
• wherein the catalyst in step (b) further promotes a water-gas shift reaction thereby adjusting the ratio of hydrogen gas to carbon monoxide gas present in the purified syngas.

A process for decontaminating syngas, comprising:

• a) contacting raw syngas with an admixture of sorbents chosen from:
• i) kaolin clays or kaolin-containing materials, amorphous aluminosilicates, aluminates, and silicates, and calcium-based sorbents that capture trace metals;
• ii) calcium-based sorbents that capture sulfur-containing species;
• and
• iii) calcium-based or magnesium-based sorbents that capture halides-containing contaminants chosen from chlorine, bromine, fluorine, iodine, hydrogen chloride, hydrogen bromide, hydrogen fluoride, and hydrogen iodide, and
• iv) sorbents that can remove more than one of the contaminants listed in (i) to (iii);
• at high temperatures equal to or greater than about 700° C. thereby capturing onto sorbent particles one or more contaminates chosen from metals, sulfur species, and halides wherein the sorbent particles are captured in a downstream filter to form a decontaminated syngas;
• b) passing the decontaminated syngas formed in step (a) through a catalytic cracking filter element thereby removing the sorbent particles and ash and cracking tars and other hydrocarbon components, wherein the cracking filter comprises a rare earth metal oxide or salt, a transition metal oxide or salt, or a combination thereof thereby forming a sulfur-free, metal free, cracked syngas;
• c) passing the sulfur-free, metal free, cracked syngas into a cooling zone wherein the syngas is cooled to a temperature of at least 370° C. to form a cooled sulfur-free, metal free, cracked syngas;
• and
• d) passing the cooled, sulfur-free, metal free, cracked syngas into a vessel comprising a source of nitric oxide, wherein the nitric oxide reacts with ammonia contaminants present in the sulfur-free, metal free, cracked syngas to produce a purified syngas.

A method for purifying syngas, comprising:

• a) contacting a source of raw syngas with one or more sorbents chosen from:
• i) kaolin clays or kaolin-containing materials;
• ii) calcium-based sorbents;
• thereby removing metal and sulfur contaminants to form a decontaminated syngas;
• and
• b) passing the decontaminated syngas formed in step (a) through a catalytic filter element to thereby remove solid particles and ash and wherein further tars are cracked, the catalytic filter element comprising a rare earth metal oxide or salt, a transition metal oxide or salt, or a combination thereof, thereby forming purified syngas.