Continuous thermal hydrolysis and energy integration in sludge anaerobic digestion plants

2008 ◽  
Vol 57 (8) ◽  
pp. 1221-1226 ◽  
Author(s):  
F. Fdz-Polanco ◽  
R. Velazquez ◽  
S. I. Perez-Elvira ◽  
C. Casas ◽  
D. del Barrio ◽  
...  

A thermal hydrolysis pilot plant with direct steam injection heating was designed and constructed. In a first period the equipment was operated in batch to verify the effect of sludge type, pressure and temperature, residence time and solids concentration. Optimal operation conditions were reached for secondary sludge at 170°C, 7 bar and 30 minutes residence time, obtaining a disintegration factor higher than 10, methane production increase by 50% and easy centrifugation In a second period the pilot plant was operated working with continuous feed, testing the efficiency by using two continuous anaerobic digester operating in the mesophilic and thermophilic range. Working at 12 days residence time, biogas production increases by 40–50%. Integrating the energy transfer it is possible to design a self-sufficient system that takes advantage of this methane increase to produce 40% more electric energy.

2012 ◽  
Vol 65 (10) ◽  
pp. 1839-1846 ◽  
Author(s):  
S. I. Pérez-Elvira ◽  
F. Fdz-Polanco

Experimental data obtained from the operation in a pilot plant are used to perform mass and energy balances to a global process combining units of thermal hydrolysis (TH) of secondary sludge, anaerobic digestion (AD) of hydrolysed secondary sludge together with fresh primary sludge, and cogeneration from biogas by using a gas engine in which the biogas produces electricity and heat from the exhaust gases. Three scenarios were compared, corresponding to the three digesters operated: C (conventional AD, 17 days residence time), B (combined TH + AD, same time), and A (TH + AD at half residence time). The biogas production of digesters B and A was 33 and 24% better, respectively when compared with C. In the case of the combined TH + AD process (scenarios A and B), the key factors in the energy balance were the recovery of heat from hot streams, and the concentration of sludge. The results of the balances showed that for 8% DS concentration of the secondary sludge tested in the pilot plant, the process can be energetically self-sufficient, but a fraction of the biogas must by-pass the gas engine to be directly burned. From an economic point of view, scenario B is more profitable in terms of green energy and higher waste removal, while scenario A reduces the digester volume required by a half. Considering a population of 100,000 inhabitants, the economic benefit is 87,600 €/yr for scenario A and 132,373 €/yr for B. This value can be increased to 223,867 €/yr by increasing the sludge concentration of the feeding to the TH unit to a minimum value that allows use of all the biogas to produce green energy. This concentration is 13% DS, which is still possible from a practical point of view. Additional benefits gained with the combined TH + AD process are the enhancement of the digesters rheology and the possibility of getting Class A biosolids. The integration study presented here set the basis for the scale-up to a demonstration plant.


2015 ◽  
Vol 12 (2) ◽  
pp. 47-50
Author(s):  
Pavol Porvaz ◽  
Ján Gaduš ◽  
Štefan Tóth ◽  
János Jóvér

Abstract “Dry fermentation“ technology may be used for energy recovery of phytomass substrate which has dry matter content from 20 to 60%. In agriculture sector, while only rarely used, it is a very perspective technology at such types of biomass – phytomass which is not recommended to be processed within “wet fermentation” (process is energetically and operationally very costly). For detecting the suitability of Miscanthus × giganteus phytomass to biogas for production through dry fermentation process, as well as determining the biogas yield, at the Slovak university of Agriculture (SUA) there has been developed an experimental device enabling the pilot plant trials, which is installed at the biogas station within the area of the VPP SPU Ltd. in Kolíňany. A pilot plant experiment of biogas production based on Miscanthus × giganteus (Miscanthus sinensis Anderss.) phytomass within dry fermentation process was carried out at the period from 25 February to 25 March 2013. The monitored production of biogas was based on the substrate mixture of components formed as follows: the biomass from preceding cycle (farmyard manure) and ensilage from Miscanthus phytomass. In these experiments the amount of produced biogas, analysis of biogas and the input substrate were materialized by standard methodology. On base of the obtained results, we can formulate the conclusion: the tested substrate mainly consists of Miscanthus phytomass and manure was suitable for biogas production technology and anaerobic dry fermentation process. The yield of Miscanthus substrate in our experiments was around 117 litres of biogas per 1 kg of dry matter silage. For assurance of the continuity and uniformity in the production of biogas by dry fermentation process, the multiple-fermentation chamber is needed, which must be saturated gradually with dosing interval. This dosing interval is caused by residence time and the number of chambers. For example, at the residence time of 28 days and 4 chambers, the need of the substrate change will be on weekly base in each chamber.


2015 ◽  
Vol 2 (3) ◽  
pp. 26-31
Author(s):  
K. Węglarzy ◽  
Yu. Shliva ◽  
B. Matros ◽  
G. Sych

Aim. To optimize the methane digestion process while using different recipes of substrate components of ag- ricultural origin. Methods. The chemical composition of separate components of the substrate of agricultural by-products, industrial wastes, fats of the agrorefi nery and corn silage was studied. Dry (organic) mass, crude protein (fat) fi ber, loose ash, nitrogen-free exhaust were estimated in the components and the productivity of biogas was determined along with the methane content. These data were used as a basis for daily recipes of the substrate and the analysis of biogas production at the biogas station in Kostkowice. Results. The application of by-products of agricultural production solves the problem of their storage on boards and in open containers, which reduces investment costs, related to the installation of units for their storage. Conclusions. The return on investment for obtaining electric energy out of agricultural biogas depends considerably on the kind of the substrate used and on technological and market conditions.


2012 ◽  
pp. 756-761 ◽  
Author(s):  
Miroslav Hutnan ◽  
Štefan Tóth ◽  
Igor Bodík ◽  
Nina Kolesárová ◽  
Michal Lazor ◽  
...  

The possibility of joint treatment of spent sugar beet pulp and wastewater from a sugar factory was studied in this work. Works focused on processing of spent sugar beet pulp separately or together with other substrates can be found in the literature. In the case of some sugar factories, which have spare capacity in the anaerobic reactor on an anaerobic-aerobic wastewater treatment plant, joint processing of spent sugar beet pulp and wastewater from the sugar factory might be an interesting option. The results of the operation of a pilot plant of an anaerobic reactor with a capacity of 3.5 m3 are discussed. Operation of the pilot plant confirmed the possibility of cofermentation of these materials. The organic loading rate achieved in the anaerobic reactor was higher than 6 kg/(m3·d) (COD), while more than half of the load was provided by spent sugar beet pulp. The addition of sugar beet pulp decreased the concentration of ammonia nitrogen in the anaerobic reactor and it was even necessary to add nitrogen. However, the nitrogen content in sludge water depends on the C:N ratio in the processed sugar beet pulp, therefore this knowledge cannot be generalized. About 1.5 to 2-fold biogas production can be expected from the cofermentation of wastewater with sugar beet pulp in an anaerobic reactor, compared with the biogas production from just wastewater treatment.


2013 ◽  
Vol 46 (16) ◽  
pp. 253-258 ◽  
Author(s):  
K.E. Hakobyan ◽  
H.Y. Sohn ◽  
A.K. Hakobyan ◽  
E. Blanco ◽  
A.B. Tarasov ◽  
...  

2013 ◽  
Vol 634-638 ◽  
pp. 382-385
Author(s):  
Ke Guo Liu ◽  
Li Li Gu ◽  
Hui Guang Hu ◽  
Rong Yang ◽  
Jun Tao

The experimental studies for purification of 1,8-cineole by vacuum batch distillation as well as the application of additives in 1,8-cineole purification were carried out. There were two steps during the purification. In the first step, experimental results showed that the optimal operation conditions for purification of 1,8-cineole were the temperature of the reboiler at about 320.15 K under a certain vacuum degree. In the second step, the optimal operation temperature of the reboiler was 331.15 K. The optimal reflux ratio was generated finally. Vacuum degree was controlled between 1.1 kPa and 1.3 kPa.


2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
Satu Ojala ◽  
Ulla Lassi ◽  
Paavo Perämäki ◽  
Riitta L. Keiski

Catalytic oxidation is a feasible and affordable technology for solvent emission abatement. However, finding optimal operation conditions is important, since they are strongly dependent on the application area of VOC incineration. This paper presents the results of the laboratory experiments concerning four most central parameters, that is, effects of concentration, gas hourly space velocity (GHSV), temperature, and moisture on the oxidation of n-butyl acetate. Both fresh and industrially aged commercial Pt/Al2O3catalysts were tested to determine optimal process conditions and the significance order and level of selected parameters. The effects of these parameters were evaluated by computer-aided statistical experimental design. According to the results, GHSV was the most dominant parameter in the oxidation of n-butyl acetate. Decreasing GHSV and increasing temperature increased the conversion of n-butyl acetate. The interaction effect of GHSV and temperature was more significant than the effect of concentration. Both of these affected the reaction by increasing the conversion of n-butyl acetate. Moisture had only a minor decreasing effect on the conversion, but it also decreased slightly the formation of by products. Ageing did not change the significance order of the above-mentioned parameters, however, the effects of individual parameters increased slightly as a function of ageing.


2001 ◽  
Vol 44 (4) ◽  
pp. 109-116 ◽  
Author(s):  
A. Bonmatí ◽  
X. Flotats ◽  
L. Mateu ◽  
E. Campos

Feasibility of anaerobic digestion of pig slurry is dependent, among other factors, on the biogas production rate, which is low compared with other organic wastes, and on the profitable uses of surplus thermal energy produced, a limiting factor in warm geographical areas. The objectives of this work are determining whether low temperature thermal pretreatment (<90°C) improves pig slurry anaerobic digestion, and determining whether organic matter degradation during the thermal pretreatment is due to thermal phenomena (80°C) or to enzymatic ones (60°C). The thermal degradation tests showed that hydrolysis occurring during the thermal pretreatment is due to thermal phenomena. The increase in soluble substances were significantly larger at 80°C than at 60°C (both during 3 h). Two types of slurry were used in the batch anaerobic digestion tests. The effect of thermal pretreatment differed with the type of slurry: it was positive with almost non-degraded slurries containing low NH4+-N concentration, and negative (inhibition of the anaerobic digestion process) when using degraded slurries with high NH4+-N content.


2018 ◽  
Vol 12 (1) ◽  
pp. 158-167 ◽  
Author(s):  
Renata Piacentini Rodriguez ◽  
Carolina Manochio ◽  
Bruna de Souza Moraes

2004 ◽  
Vol 58 (12) ◽  
pp. 563-568 ◽  
Author(s):  
Mihajlo Stankovic ◽  
Nadica Stojanovic ◽  
Nada Nikolic ◽  
Vesna Novkovic

The kinetics of extraction of total lipids from ground parsley (Petroselinum crispum (Mill.) Nym. ex. A.W. Hill) seeds with a mixture of ethanol or methanol with non-polar organic solvents, chloroform, carbon tetrachloride, trichloroethylene and petroleum ether, at various temperatures were studied. The maceration technique with reflux was used. The kinetic parameters were determined in extraction kinetic equations, as well as the optimal operation conditions for total lipids extraction. The maximum total lipids yield under optimal conditions was 33.7 g per 100 g of dry parsley seeds. Nine lipid fractions of the total lipids were separated by thin layer chromatography among which were phospholipids, sterol, mono-, di- and triacylglycerol, free fatty acids and carbohydrates.


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