Technoeconomic assessment of highpressure peat liquefaction

The study is part of a research program, the aim of which is to identify the most promising process concept for the conversion of peat info transport fuels by high-pressure liquefaction. The study consists of techno-economic assessments of a base-ease concept and of four sensitivity-ease consepts. The products are heavy primary oils which require further upgrading into transport fuels. The designs of the processes were based on data generated in bench-scale experiments. The feedstock capacity of the base-case concept was 1 990 t/d of milled peat (50wt% moisture), and the main results of the economic evaluation of this concept were (costs as of mid-1985): - total capital requirement 86 x 106 USD (8 % interest rate), - production costs of primary product 6.4 USD/GJ (for peat price of 1.7 USD/GJ) - overall thermal efficiency 62 % (HHV basis). On the basis of the results of the sensitivity studies it was concluded that thermal drying of milled peat, prior to liquefaction, is advantageous; that the concentration of peat in the feed slurry should be limited to about 30 wt% solids; that operating pressures lower than 20 MPa should be sought; and that the economics of the process are not sensitive to the chosen method separating solids from the product stream. A preliminary estimate of the costs of upgrading the primary product info gasoline was also made. Gasoline production costs in the range 10 - 12 USD/GJ were obtained for the base case. This is a promising result, particularly when the Finnish refinery price (exclusive of taxes) is used as a reference.