秸秆热解炭化多联产技术应用模式及效益分析

Utilization model and its efficiency analysis of biochar-gas-oil polygeneration by straw pyrolysis

通过秸秆热解多联产技术,能够将废弃的秸秆转化为燃气和生物炭等,既能提供清洁能源,改善用能结构,又能有效还田和固碳,具有较好的推广应用潜力。分析内加热式移动床生物质炭气联产技术、外加热式移动床生物质热解炭气联产技术、外加热式移动床生物质热解炭气油联产技术的工艺参数,提出了适宜自然村、村镇社区和规模化应用等3种不同规模用户的秸秆热解炭化生产技术应用模式,并以不同规模秸秆利用量为例,得到消耗每吨秸秆的纯利润分别为87、135和141元/t,销售利润率20%左右,温室气体碳排放交易可增加8%左右的纯收益,经济与环境效益良好。

There are about 7 tons of straw produced in China each year, about half of them have not been used effectively.Straw pyrolysis polygeneration technology changed wastes and straw into biochar, which can not only provide clean energy,improve the energy structure, but also fix carbon and realize carbon reapplication, so it has good application potential. Threekinds of process characteristics of internal heating type moving bed of biomass carbon gas cogeneration technology, andexternal heating type moving bed pyrolysis carbon gas cogeneration technology, external heating type moving bed pyrolysiscarbon gas generation technology were analyzed, the suitability of three technologies were evaluated. Three processes havetheir own technological advantages. With internal heating type pyrolysis carbon gas production technology, the calorific valueof gas is slightly lower, which is 3-6 MJ/kg; but investment cost is low, because its equipment is relatively simple and almostno external energy consumption, which effectively reduced the cost of equipment and fuel consumption. So it is suitable forhundreds of thousands of households to thousands of natural villages. The pyrolysis gas production technology mode of theprimary pyrolysis gas after secondary pyrolysis, its heating rate is twice as high as that of the internal heating type, and itsenergy conversion rate is 40% to 60%; This mode can be directly used to provide cooking through the gas pipeline directly tothe village community to focus on gas supply. Although the equipment cost and energy consumption of external heating andsecondary pyrolysis are increased, the problem of difficult to deal with the by-products such as tar is solved, ensured theenvironmental benefits of the application of technical engineering. That is suitable for the rural community centralized gassupply of over 1000 households; The pyrolysis gas, carbon and oil three-state products of the external heating pyrolysismulti-generation technology are effectively collected. As a terminal product, the efficiency of energy conversion is high,maximizing the use of the pyrolysis process of all the energy. The gas calorific value is higher than that of the process one andlower than process two, which can be used for cooking more than 10 000 households, industrial park gas supply or powergeneration, etc. Therefore, it is suitable for large-scale pyrolysis carbon gas production technology model. The annualutilization of 2000, 5000 and 10000 t straw raw materials for three models as an example, the cost of three different models ofstraw consumption per ton of straw were 362, 569, 536 yuan/t, income were 449, 704, 678 yuan/t, net profit were 87, 135 and141 yuan/t, sales were about 20% profit margin, the greenhouse gas carbon emission trading income is 7.8, 13.1, 10.8 yuan/t,the greenhouse gas emissions of carbon dioxide emissions of 0.48, 0.82, 0.67 t, carbon emissions trading price was 16 yuardt,respectively, an increase was 8.2%, 8.8%, 7.1% of the net profit, good economic and environmental benefits, respectively.