Landfill Treatment (H2S & Siloxane Removal)

Overview of landfill Gas

Landfill gas is a natural byproduct of the decomposition of organic material in landfills. This gas is composed of roughly 50% methane, 50% carbon dioxide, and a small amount of nonmethane organic compounds. Landfill sites use various equipment and technology to treat this gas into achieving acceptable compositions of impurities for pipeline requirements. The treatment process of Landfill gas has three major stages:

1. Primary Treatment – Moisture Removal (H₂O removal)
2. Secondary Treatment – Impurity Removal (H₂S and Siloxane removal)
3. Advanced Treatment – Purity Achievement Based (CO₂, N₂, O₂, VOC removal)

Siloxane Removal

Removing siloxane is an important step in cleaning methane gases for use as fuel since siloxane is a form of crystalline silica that will essentially turn into glass when burned or combusted. The collection of combusted siloxanes inside of engine components can cause the buildup of heat, water, and other contaminants that can cause corrosion, leading to problems in the engine.

Molecular Sieve 13X Applications

HYD10A is manufactured to deeply dehydrate feed gas prior to cryogenic separation by removing water, carbon dioxide, and other contaminants from feed gas. The removal of these contaminants will allow the feed gas to be further separated into the desired
product stream. This molecular sieve has an ideal selectivity for removing impurities that can freeze or block cryogenic separation processes.

• • Used to deeply dehydrate feed gas
• • Capable of removing water, carbon dioxide, hydrocarbons, and more
• • Allows gas to be further separated or otherwise used in compressors
• • Offers an advantageous adsorption capacity for a wide range of impurities

Siloxane Removal Schematic

Aside from removing siloxane due to impurity specification requirements it also serves as the solution for better machinery life-cycles and ensures longevity of end products from landfill gas plant.

Isotherm Data

These charts indicate that HYD10A shows high N₂, and CO₂ separation under a very low pressure, which lowers the consumption of oxygen during generation and improves economic performance. HYD10A molecular sieve is most commonly used to remove contaminants such as water, carbon dioxide, and hydrocarbons from feed gas in air pre-purification units prior to cryogenic air separation. This molecular sieve will also remove hydrogen sulfide, mercaptans, and high molecular weight sulfur compounds in LNG, LPG, and liquid hydrocarbon streams, such as propane and butane.

Specifications of 13X

(¥a x [(AlO₂)a(SiO₂)b] x _cH₂O (¥ = Na)

H2S Removal

Removal of H₂S is a critical procedure that helps reduce corrosion for power generation equipment, pre-treat LFG for high-BTU gas processing, and to reduce sulfur oxides (SO_x) emissions, associated with LFG combustion.

Activated Alumina for Desulfurization (HYAS200)

This special adsorbent is a smooth, spherical adsorbent which has demonstrated its superior performance applied in the selectivity of removing COS, H₂S, CS₂ and any other mercaptans impurity from hydrocarbon streams.

Removes H₂S from following sources:

• • Biogas that originates in sewage treatment plants due to anaerobic conditions in sludge
• • Agricultural biogas
• • Gases from anaerobic industrial sewage treatment facilities
• • Landfill gas
• • Industrial combustion and synthetic gases
• • Waste and co-fermentation plant biogas after anaerobic digestion
• • Miscellaneous H₂S containing industrial exhaust gas (i.e. paper industry, oil-mill applications)
• • The treatment of H₂S containing exhaust from industries and wastewater treatment facilities

Specifications of HYAS200 (Activated Alumina for Desulfurization)

HYAS200 eliminates H₂S and Mercaptans from landfill gas and deactivates gradually from inlet to outlet through a packed
bed, discarding behind a free-flowing, non-hazardous by-product. Typical H2S Removal System units will have 2-3 vessels in place to achieve this removal process.

HYAS200 is a very porous form of aluminum oxide of high surface, typical chemical formula AI₂O₃ x nH₂O.

Products for landfill gas

• · HYD10A (4×8, 8×12) – Siloxane Removal

Removing siloxane is an important step in cleaning methane gases for use as fuel since siloxane is a form of crystalline silica that will essentially turn into glass when burned or combusted. The collection of combusted siloxanes inside of engine components can cause the buildup of heat, water, and other contaminants that can cause corrosion, leading to problems in the engine.

Removal of H₂S is a critical procedure that helps reduce corrosion for power generation equipment, pre-treat LFG for high-BTU gas processing, and to reduce sulfur oxides (SOx) emissions, associated with LFG combustion.