生物质煤气废水氨氮脱除的研究

生物质煤气废水是一种新出现的高浓度氨氮有机废水。作者采用化学沉淀法去除该废水中的氨氮，研究了不同沉淀剂、pH、温度和搅拌时间对氨氮去除效果的影响。结果表明，MgCl2＋Na3PO4·12H2O明显优于其他沉淀剂组合。当n（Mg^2＋）：n（NH4^＋）：n（PO4^3-）=1：1：1、pH10．0、温度30℃、搅拌时间30min时，废水中的氨氮质量浓度从处理前的222mg/L降到17mg／L，去除率为92.3％。

生物质气化与废弃物焚烧联合发电的技术经济分析

介绍了生物质气化与废弃物焚烧联合发电技术项目，确定了该项目经济效益的评价指标，定量计算了项目的投资回收期、净现值和内部收益率。同时还对燃料费用、上网电价和固定资产变化引起的敏感性进行分析。结果表明，该联合发电技术的动态投资回收期为9.05a，净现值为2770万元，内部收益率为15.82％，三个经济指标均符合行业标准。从经济角度看是完全可行的。

Scale study of direct synthesis of dimethyl ether from biomass synthesis gas

We investigated the synthesis of dimethyl ether (DME) from biomass synthesis gas using a kind of hybrid catalyst consisting of methanol and HZSM-5 zeolite in a fixed-bed reactor in a 100 ton/year pilot plant. The biomass synthesis gas was produced by oxygen-rich gasification of corn core in a two-stage fixed bed. The results showed that CO conversions reached 82.00% and 73.55%, the selectivities for DME were 73.95% and 69.73%, and the space-time yields were 124.28 kg m- 3 h- 1 and 203.80 kg m- 3 h- 1 when gas hourly space velocities were 650 h- 1 and 1200 h- 1, respectively. Deoxidation and tar removal from biomass synthesis gas was critical to the stable operation of the DME synthesis system. Using single-pass synthesis, the H2/CO ratio improved from 0.98-1.17 to 2.12-2.22. The yield of DME would be increased greatly if the exhaust was reused after removal of the CO2.

The design and operation of a new clapboard-type internal circulating fluidized-bed gasifier

The design and operation of a new clapboard-type internal circulating fluidized-bed gasifier is proposed in this article. By arranging the clapboard in the bed, the gasifier is thus divided into two regions, which are characterized by different fluidization velocities. The bed structure is designed so that it can guide the circulating flow passing through the two regions, and therefore the feedstock particles entrained in the flow experience longer residence time. The experimental results based on the present new design, operating in the temperature range of 790 degrees C-850 degrees C, indicate that the gas yield is from 1.6-1.9 Nm(3)/kg feedstock, the gas enthalpies are 5,345 kJ/Nm(3) for wood chip and 4,875 kJ/m(3) for rice husk, and a gasification efficiency up to 75% can be obtained.

A study on the economic efficiency of hydrogen production from biomass residues in China

As part of Pilot Project of KIP of CAS, a feasibility study of hydrogen production system using biomass residues is conducted. This study is based on a process of oxygen-rich air gasification of biomass in a downdraft gasifier plus CO-shift. The capacity of this system is 6.4 t biomass/d. Applying this system, it is expected that an annual production of 480 billion N m(3) H-2 will be generated for domestic supply in China. The capital cost of the plant used in this study is 1328$/(N m(3)/h) H-2 out, and product supply cost is 0.15$/N m(3) H-2. The cost sensitivity analysis on this system tells that electricity and catalyst cost are the two most important factors to influence hydrogen production cost.