From landfill to the tomato plant – purified biogas powers ... - Eco-Tec

Te c h n o l oCa g y sSp e in o tPo lTe i g i n h x tThis specific BgPur configuration – which features twocontactor tanks rather than one – was installed for RGMRMbecause of the large volume of gas coming from the landfill(3,085 Nm 3 /hour). Each contactor can handle about 1,500Nm 3 /hour.The overall system eliminated the need for 9 million m 3 /year of natural gas and, as a result, reduced Greenhouse Gas(GHG) emissions by approximately 135,000 tons of CO 2forthe client. The H 2S in the treated gas is less than 1ppmv, andgenerally below the detection limit of 0.2 ppmv more than theentire inlet concentration range.SystemThe H 2S scrubber system is designed with a patentedmass transfer technology that allows the H 2S to be absorbedinto solution where the chemistry converts it into elementalsulfur. The system takes advantage of the oxygen present inlandfill gas, which regenerates the absorption chemistry atthe same time. The elemental sulfur floats to the surface as afroth/foam where it overflows into a slurry thickening section.The slurry is pumped to a filter press which removes the solidsulfur and returns the filtrate back to the contactor for a fullyclosed-loop process.The filter press provides a 60-65 w/w sulfur cake, whichis greater than 99 percent sulfur. The washed solid crystallinesulfur produced by BgPur is pure sulfur, which can be usedas an agricultural supplement that can be resold as a valuablecommodity by the client.For RGMRM, the system also delivers a simple designand operation with no packed columns, allowing continuousreliable operation without any column to plug, foul or foam;and no labor formedia cleaningor replacement.The systemarrived factoryconstructedwith a compactdesign, whichprovides a smallfootprint, shortdelivery and lowinstalled costs.The automatedcontrol systemdetects responseto changes ingas flow-rate orH 2S compositionand suppliesautomaticreagent addition.As well,Figure 3. Single contactor schematicthere’s no wasteresulting from theoperation, onlyenvironmentally acceptable solid sulfur cake, which means noadditional waste treatment equipment or operating costs areneeded; and no disposal of potentially hazardous media. CFor more information, visit www.eco-tec.comJune 2011www.GoBiomass.com11