Marine Biomass System: Anaerobic Digestion and Production of Methane

摘要

Two approaches to kelp conversion to methane are described. First, a large (10.56 mi exp 2 ) oceanic farm using an artificial substrate and an upwelling system to deliver nutrient-rich deep ocean water to the kelp bed is described. This system can yield as much as 50 tons of kelp (dry ash free - DAF) per acre-year. Kelp are harvested by a specially designed 30,000 DWT ship and delivered to an onshore processing plant as a ground kelp slurry. The second system involves the use of a natrual coastal kelp bed. Growth rates in this bed are stimulated by a nutrient rich sewer outfall. A conceptual model is presented for calculation of the growth rate of kelp in this natural bed which can reach 15 tons (DAF) per acre-year. The harvest activity and processing plant are similar to those for oceanic farm system. In the next section of this report, the overall concept of kelp production and conversion to methane is discussed. In Section III the general design of the ocean farm system is presented and discussed while Section IV contains a similar description for the natural bed system. Section V presents the capital requirements and operational labor, resources and material requirements. Section VI describes the environmental residuals created by the operation of either system and, to the extent possible, quantifies the rate at which these residuals are generated. In addition to the technical data reported herein, cost data have been generated for the various processes and components utilized in each solar technology. The requirements for costing information basically arise from the need to compute parameters such as investment demands, employment patterns, material demands and residual levels associated with each technology for each of several national and regional scenarios. (ERA citation 05:013299)