FACILITY AND METHOD FOR PRODUCING BIOMETHANE WITH LIMITED METHANE LOSS AND LIMITED CO2 EMISSIONS

• Main Authors: BARRAUD, François, VALENTIN, Solène
• Format: Patent
• Language: English
• Published: 26.10.2023
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE ORUNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; BLASTING; CHEMISTRY; COMBINED HEATING AND REFRIGERATION SYSTEMS; FIRELIGHTERS; FUELS; FUELS NOT OTHERWISE PROVIDED FOR; HEAT PUMP SYSTEMS; HEATING; LIGHTING; LIQUEFACTION SOLIDIFICATION OF GASES; LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS; LIQUEFIED PETROLEUM GAS; LUBRICANTS; MANUFACTURE OR STORAGE OF ICE; MECHANICAL ENGINEERING; METALLURGY; MIXTURES BY PRESSURE AND COLD TREATMENT; NATURAL GAS; ORGANIC CHEMISTRY; PEAT; PERFORMING OPERATIONS; PETROLEUM, GAS OR COKE INDUSTRIES; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; REFRIGERATION OR COOLING; SEPARATION; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BYSUBCLASSES C10G, C10K; TECHNICAL GASES CONTAINING CARBON MONOXIDE; TRANSPORTING; WEAPONS

Disclosed are a facility and a method using the facility for treating a feed gas stream comprising at least methane and carbon dioxide by membrane permeation, the facility comprising: -a first membrane separation unit capable of receiving the feed gas stream and providing a first permeate and a first retentate, -a second membrane separation unit capable of receiving the first retentate and providing a second permeate and a second retentate, -a compressor for compressing the first permeate to a pressure of between 17 bar and 25 bar, -a means for cooling the first compressed permeate to a temperature lower than −40° C., -a distillation column for separating the first cooled permeate into a gas stream and a liquid stream, -at least one means for recycling the gas stream exiting the distillation column to the inlet of the first membrane separation unit, -a means for measuring the concentration of methane and/or carbon dioxide in the gas stream exiting the distillation column, -a means for comparing the concentration of methane and/or carbon dioxide measured by the measurement means with a target value, and -a means for adjusting the pressure and/or the temperature of the first permeate depending on the comparison carried out by the comparison means.