NOVELTY - The method comprises flowing an inert gas through a multistage compressor, a bypass conduit (100) and a recycling conduit (132) of the system for a sufficient time such that the system achieves a sufficient operating pressure, allowing a portion of inert gas to flow through acetylene removal units (44) of the system until the acetylene removal units achieve the sufficient operating pressure, and introducing a cracked raw gas into the compressor such that a portion of the cracked gas flows through the acetylene removal units. The acetylene removal system further comprises cracking furnaces.    USE - The method is useful for starting a system for removing acetylene from a cracked gas mixture (claimed).    ADVANTAGE - The method is capable of effectively and easily starting an acetylene removal system thus enabling effective removal of acetylene from the cracked gas mixture with reduced capital equipment costs.    DETAILED DESCRIPTION - The method comprises flowing an inert gas through a multistage compressor, a bypass conduit (100) and a recycling conduit (132) of the system for a sufficient time such that the system achieves a sufficient operating pressure, allowing a portion of inert gas to flow through acetylene removal units (44) of the system until the acetylene removal units achieve the sufficient operating pressure, and introducing a cracked raw gas into the compressor such that a portion of the cracked gas flows through the acetylene removal units. The acetylene removal system further comprises cracking furnaces (12, 14), and a series of post-acetylene reduction purifiers for separating and purifying hydrocarbons contained in the raw cracked gas mixture after acetylene reduction. The multistage compressor communicates with the cracking furnaces for compressing the raw cracked gas. The acetylene removal units communicate with the multistage compressor. Each acetylene removal unit comprises a palladium containing catalyst that selectively reduces acetylene to ethylene. The acetylene removal units are capable of operating for a period of not less than one year before regenerating of the palladium catalyst is necessary. The raw cracked gas flows from the cracking furnaces to the multistage compressor and then through each of the acetylene removal units. The bypass conduit is configured for diverting the raw cracked gas mixture such that the mixture does not flow through the acetylene removal units. The recycling conduit is located upstream from the series of pos-acetylene reduction purifiers for recycling gas that is flowed through the bypass conduit or through the acetylene removal units to the multistage compressor. The raw cracked gas mixture is cooled prior to contacting the acetylene removal units. The carbon monoxide is added to the inert gas before contacting the acetylene removal units if the acetylene removal units contain fresh catalyst. A sulfur containing compound is injected into the raw cracked gas mixture. The temperature of the raw cracked gas mixture is increased to a temperature of 120-150 degrees F. An INDEPENDENT CLAIM is included for a cracked gas purification apparatus for removing acetylene from a raw cracked gas mixture.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a cracked gas purification apparatus.    Cracking furnaces (12, 14, 16, 18, 20, 22)    Compression stage (36, 42)    Acetylene removal units (44, 46)    Bypass conduit (100)    Recycling conduit. (132)