A natural chemical mechanical pulping process for camphor wood using sodium hydroxide

Abstract

The invention belongs to the field of chemical mechanical pulping. The invention discloses a natural color chemical mechanical pulping process of camphor wood sodium hydroxide, comprising: S1, softening and extruding and tearing camphor wood chips, and then using water vapor to perform segmented distillation treatment, wherein the initial distillation temperature is lower than 120°C, so that the extraction rate of camphor oil is ≥96%; S2, steaming and extruding and tearing the camphor wood chips after the segmented distillation treatment, and then reacting with an alkaline liquid containing a wood chip penetrant; S3, grinding the reacted materials through a pressure mill, dehydrating, eliminating latent, screening and concentrating to obtain a natural color chemical mechanical pulp. According to the characteristics of camphor wood, such as greater density than poplar wood and difficulty in pulping, the invention can add a wood chip penetrant in a liquid impregnator to promote rapid and uniform penetration of the alkaline liquid, and good softening effect of the wood chips, so as to facilitate chemical treatment and grinding. The process of the invention has the characteristics of high camphor and camphor oil extraction rate, low pulping cost, and good pulp quality.

Description

Technical Field

[0001] The invention relates to the technical field of chemical mechanical pulping, and specifically to a natural chemical mechanical pulping process for camphor wood with sodium hydroxide, which can efficiently extract oil while producing camphor wood pulp. Background Art

[0002] Chemical mechanical pulp refers to pulp made by chemical treatment and mechanical grinding. According to different pulping processes, it includes chemical thermomechanical pulp (CTMP) and conventional chemical mechanical pulp (CMP). According to the different liquid chemicals used, CMP can be divided into cold alkali method and sulfite method. The raw materials for making paper are various fiber raw materials, such as wood (such as poplar, basswood, etc.) and non-wood (such as straw, wheat straw, etc.).

[0003] However, the traditional pulping method cannot produce camphorwood pulp, etc. Camphorwood is an evergreen tree with a fragrance throughout the plant. The bark is yellow-brown with irregular longitudinal cracks. The leaves are alternate, ovate, light-loving, shade-tolerant, but not cold-tolerant. It has low soil requirements, is relatively tolerant to water and humidity, and is not drought-tolerant. It has a deep taproot, is wind-resistant, has a long survival period, and can grow into a towering tree that lives for hundreds or thousands of years. It has a strong ability to absorb smoke and dust, conserve water resources, consolidate soil and prevent sand, and beautify the environment. It can absorb a variety of toxic gases and can adapt to urban environments. Therefore, it is mostly used as a tree species for urban greening and is widely distributed in China, Vietnam, Japan and North Korea. In China, it is mainly distributed in Jiangxi, Hunan, Hubei, Fujian, Guangdong and Zhejiang, etc., south of the Yangtze River, but there are few large-scale forests.

[0004] At present, camphor wood is mainly used as building and furniture material, and another use of camphor wood is to extract camphor and camphor oil. However, the traditional steam distillation method has a low yield of camphor oil (the traditional distillation extraction rate is about 60-70%), and the camphor and camphor oil remaining in the camphor wood chips are relatively high. The camphor and camphor oil in camphor wood will restrict the biochemical treatment of pulping wastewater and cause problems such as papermaking resin obstacles. Summary of the invention

[0005] In view of this, the present invention provides a natural color chemical mechanical pulping process of camphor wood with sodium hydroxide. The process method of the present invention uses camphor wood as a fiber raw material, which can not only improve the extraction rate of camphor oil, but also produce its chemical mechanical pulp, which can meet the quality requirements of natural color packaging paper, alleviate the tension of wood raw materials to a certain extent, and save limited wood resources. At present, there is no patent technology disclosed in this regard at home and abroad.

[0006] The present invention provides a natural color chemical mechanical pulping process of camphor wood sodium hydroxide, comprising the following steps:

[0007] S1, softening and extruding the camphor wood chips, and then using water vapor to perform segmented distillation, wherein the initial distillation temperature is lower than 120° C., so that the extraction rate of camphor oil is more than 96%;

[0008] S2, steaming and extruding and tearing the camphorwood chips after the segmented distillation treatment, and then reacting with an alkaline liquid containing a wood chip penetrant;

[0009] S3, refining the reacted materials through a pressure mill, dehydrating, delatching, screening and concentrating to obtain natural color chemical mechanical pulp.

[0010] Preferably, in step S1, the length of the camphor wood chips is controlled to be 12-40 mm, the thickness is controlled to be 3-6 mm, and the moisture content is 30-60 wt %.

[0011] Preferably, in step S1, the camphor wood chips are pre-steamed and softened at 80-85° C., and then squeezed and torn using a wood chip squeezer.

[0012] Preferably, the extrusion tearing load in step S1 is 70-85%, and the wood chip extrusion ratio is set at 1:2.5-3.

[0013] Preferably, the temperature control of the staged distillation process in step S1 includes: distillation at 110-118° C. for at least 1 hour in the initial stage and distillation at 140-180° C. in the final stage until no camphor oil is precipitated.

[0014] Preferably, the step S1 further comprises: distilling and purifying the camphor oil mixture obtained by the segmented distillation treatment, and controlling the temperature at 155-200° C. Further, the filtrate can be distilled repeatedly 3-4 times until no camphor oil is precipitated, to obtain pure camphor oil and camphor, and the steam pressure is controlled to be 0.75-1.5 Mpa.

[0015] Preferably, the step S2 specifically comprises: dehydrating the camphor wood chips after the staged distillation treatment, and then steaming them at 85-90° C., and then extruding, tearing and dehydrating them, and impregnating the obtained dehydrated materials with sodium hydroxide solution containing wood chip penetrant to react.

[0016] Preferably, the amount of sodium hydroxide is 50-55 kg / ton of pulp, the amount of wood chip penetrant is 0.5-1.0 kg / ton of pulp, the reaction temperature is controlled at 40-50° C., and the reaction time is 30-35 minutes.

[0017] Preferably, the refining in step S3 is as follows: the reacted material is refining by a first-stage pressure mill, then dewatering and squeezing, and the dewatered and squeezed pulp is refining by a second-stage pressure mill; the pressure of the first-stage pressure mill is controlled to be 110-130 kPa. In addition, the grinding plate spacing of the first-stage pressure mill is set to 0.12 mm, and the grinding plate is selected to be a 50127 model.

[0018] Preferably, in step S3, the operating load of the first-stage pressure mill after the pulping operation is controlled at 60-70%, and the pulp dryness after dehydration and pressing is more than 37%; the acceleration of the second-stage pressure mill is controlled at 50-60% ACC. In addition, the grinding disc of the second-stage pressure mill can be selected as 040 model, and the spacing between the pressure mill grinding discs is set to 0.10mm.

[0019] Furthermore, the prepared slurry is sent to a de-submersible tank for de-submersible standby use, and the liquid level, temperature and concentration of the de-submersible tank are well controlled; optimally, the liquid level of the de-submersible tank is controlled at 60-80%, the temperature is controlled at 60-70°C by low-pressure steam, and the concentration is controlled at 4.0-5.5%.

[0020] Furthermore, the pulp made by de-latching is sent to the pressure screen for screening operation, and the good pulp is screened out and sent to the double-net thickener for concentration and dehydration. Before this operation, the appropriate pressure screen gap, double-net thickener mesh, and pressure difference between the inlet and outlet of the pressure screen should be selected. When screening, the pressure of the pressure screen, the pressure difference between the inlet and outlet, and the ratio of slag to pulp should be controlled. When thickening the pulp, the pulp concentration and the number of revolutions of the thickener should be controlled; the pulp whiteness is controlled to 29±1%ISO, and the dust is not higher than 700mm 2 / kg, and the freeness is controlled at 260-320ml. Finally, the concentrated pulp can be sent to the pulp storage tower for storage and standby papermaking.

[0021] Optimized, in the screening operation of the pressure screen, the screen gap of the pressure screen is preferably 0.23mm, the pressure is controlled to 200-210kPa, the pressure difference between the inlet and outlet is controlled to 90-100kPa, the flow ratio of the slurry to the good slurry is controlled to 15-20%, and the operating load is controlled to 60-70%;

[0022] The speed of the double-net concentrator is controlled at 11-13RPM, the inlet slurry concentration is controlled at 4.0-5.0%, and the outlet slurry concentration is controlled at 12-14%.

[0023] Compared with the prior art, the present invention provides a natural color chemical mechanical pulping process method for camphor wood with high efficiency oil extraction by sodium hydroxide, which can pulp and make paper from camphor wood chips that have been boiled with camphor and camphor oil, and formulate the process flow and process parameters according to the material characteristics of camphor wood, with low pulping cost and good pulp quality, which can fully meet the needs of high-grade paper production. In the process of camphor wood oil extraction, the present invention first softens and squeezes and tears the wood chips, and then distills and extracts oil in a distillation pot, and the temperature control of the distillation is divided into two stages, wherein the initial distillation temperature is lower than 120°C, and this process technology greatly improves the extraction rate of camphor oil and camphor, and the extraction rate reaches more than 96%, and solves the problems of difficult pulping wastewater treatment and papermaking resin obstacles. In the process of chemical mechanical pulping, according to the characteristics of camphor wood such as greater density than poplar wood and difficulty in pulping, a wood chip penetrant can be added to the liquid impregnator to promote rapid and uniform penetration of the alkaline liquid, and the softening effect of the wood chips is good, so as to facilitate chemical treatment and pulping. The process of the invention has the characteristics of high camphor and camphor oil extraction rate, low pulping cost, good pulp quality and the like.

[0024] After experimental verification, the method of the embodiment of the present invention extracts camphor and camphor oil from such camphor wood chips and pulps them. The extraction rate of camphor and camphor reaches more than 96%. After pulping, the average fiber length is about 0.84 mm, the fiber width is about 25.6 microns, the fiber aspect ratio is about 40, and the freeness CSF is 314ml. The breaking length is about 2.42km, the tear index is about 2.7, and the bulk thickness is 2.90cm 3 / g, whiteness 28.86%ISO, which can meet the quality requirements of natural color packaging paper. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0026] The present invention provides a natural color chemical mechanical pulping process of camphor wood sodium hydroxide, comprising the following steps:

[0027] S1, softening and extruding the camphor wood chips, and then using water vapor to perform segmented distillation, wherein the initial distillation temperature is lower than 120° C., so that the extraction rate of camphor oil is more than 96%;

[0028] S2, steaming and extruding and tearing the camphorwood chips after the segmented distillation treatment, and then reacting with an alkaline liquid containing a wood chip penetrant;

[0029] S3, refining the reacted materials through a pressure mill, dehydrating, delatching, screening and concentrating to obtain natural color chemical mechanical pulp.

[0030] The camphor wood pulping process provided by the invention is a process technology which can solve the problems of low extraction rate of camphor and camphor oil, influence of camphor oil in camphor wood chips on biochemical treatment of pulping wastewater, resin obstacle of camphor wood pulping for papermaking, and difficulty in pulping due to high density of camphor wood chips, and has important significance.

[0031] To achieve the above purpose, the embodiment of the present invention takes camphor wood for peeling, chipping, screening, washing and dehydration operations. After screening, the length of the camphor wood chips is controlled to be 12-40 mm; the thickness of the wood chips is controlled to be 3-6 mm; in terms of mass percentage, the qualified rate of the wood chips is controlled to be above 70%, the bark rate is less than 0.2%, and the moisture content of the camphor wood chips is 30-60%, preferably 30-50%.

[0032] Camphor wood has a high density, generally between 0.43-0.56 g / cm 3 ; The traditional method is to extract camphor oil by single temperature steam distillation. However, the embodiment of the present invention first washes, dehydrates, pre-steams and softens, squeezes and tears the wood chips, and then puts them into the distillation pot for segmented distillation to extract oil. The initial distillation temperature is controlled to be less than 120°C, and the distillation time is until no camphor oil is precipitated. The extraction rate of camphor oil is above 96%. In addition, the process of the embodiment of the present invention can also be called the pulping process of sodium hydroxide natural chemical mechanical pulp for efficient oil extraction from camphor wood.

[0033] The process flow design of extracting camphor and camphor oil from camphor wood chips in the embodiment of the present invention is as follows: first, the camphor wood chips are washed and dehydrated, pre-steamed and softened, squeezed and torn, and then temperature-controlled and graded distilled to extract camphor oil. This process technology has a high camphor oil extraction rate and is beneficial to the technical bottleneck of pulping and papermaking of camphor wood chips.

[0034] In the above-mentioned extraction process of the embodiment of the present invention, one of the key technologies for high extraction rate of camphor and camphor oil is: before distillation, a pre-steaming and softening treatment is adopted in a pre-steaming bin, and then extrusion and tearing are performed by a wood chip extruder. Among them, the screened camphor wood chips are loaded into a pre-steaming bin, and the pre-steaming and softening conditions are preferably 80-85°C for 15 minutes; enter the extruder for extrusion and tearing, and the extruder controls the extrusion load to be 70-85%, and the wood chip extrusion ratio is preferably set at 1:2.5-3, and more preferably 1:2.8.

[0035] Next, in the embodiment of the present invention, the extruded and torn wood chips are loaded into a 1# distillation pot, and water vapor is introduced for distillation. The camphor oil enters the cooler along with the steam from the top of the distillation pot and is condensed into a liquid (until there are no oil droplets in the condensate), and flows into the enamel barrel for separation of camphor and camphor oil, and the separated water is sent to the steamer for recycling; the distillation temperature is controlled in two stages, preferably controlled at 110-118° C. in the initial stage, and distilled at 140-180° C. in the second stage after at least 1 hour, and the distillation time is until no camphor oil is precipitated, generally a total of 1-1.5 hours.

[0036] According to the positive correlation between the release rate of camphor in camphor wood chips and temperature and time, the embodiment of the present invention adopts a one-time distillation divided into two stages with different temperature heating control, so that the extraction rate of camphor oil in camphor wood chips is greatly improved to more than 96%. At this time, the camphor oil remaining in the camphor wood chips is very little, so that it is suitable for pulping, the wastewater biochemical treatment is normal, the activated sludge deactivation phenomenon is not likely to occur, and the resin barrier of papermaking disappears (currently there is no pulping process technology or production line for camphor wood chips at home and abroad).

[0037] Preferably, the camphor oil mixture obtained by the segmented distillation treatment is also pumped into the 2# distillation pot for secondary distillation and purification of camphor oil. The filtrate can be distilled 3-4 times repeatedly until no camphor is precipitated to obtain pure camphor oil and camphor; the secondary distillation temperature is preferably controlled at 155-200°C, at which time the extraction rate can reach more than 99%. The embodiment of the present invention adopts secondary distillation, and the primary distillation is heated in two stages. This process technology greatly improves the extraction rate of camphor and camphor oil. After secondary distillation and purification, the purity of camphor oil reaches more than 99%, and solves the problems of difficult treatment of pulping wastewater and papermaking resin obstacles.

[0038] In the embodiment of the present invention, the camphor wood chips after the staged distillation treatment are sent to a single screw dehydrator for dehydration, and then transported to a two-stage pre-steaming bin for steaming. During the pre-steaming process, temperature and time are controlled, preferably with low-pressure steam heated to 85-90° C. for 30 minutes and low-pressure steam 0.4-0.6 MPa; then sent to a two-stage extruder for extrusion, tearing and dehydration, and the extrusion load of the extruder can be controlled at 60-70%.

[0039] After obtaining the dehydrated material, the embodiment of the present invention puts it into a stage 1 liquid pre-impregnation device, and adds sodium hydroxide liquid containing wood chip penetrant and mixes evenly. After pre-impregnation for 10 minutes, it can be put into the reaction chamber for chemical reaction. After the reaction is completed, it enters the steaming pipe for heating, and the liquid level of the reaction chamber, reaction time, reaction temperature, and the amount of sodium hydroxide and wood chip penetrant added are controlled.

[0040] In the liquid impregnation device, add 50-55kg / ton of pulp of sodium hydroxide and 0.5-1.0kg / ton of pulp of wood chip penetrant, mix evenly, and put into the reaction chamber for chemical reaction. The wood chip penetrant is preferably a polyethylene glycol fatty acid ester penetrant, for example, its density at 25°C is 1.00-1.05g / cm 3; The pH value of the stock solution can be 5.0-9.5, and the penetration force: 1.5g / L aqueous solution <10s, and commercially available products can be used. Furthermore, temperature, time, and liquid level control are performed during the reaction process, and the liquid level of the reaction chamber is controlled at 60-80%, the temperature is controlled at 40-50°C, and the time is 30-35 minutes. In addition, it is preferred to control the temperature of the steaming pipe at 80-90°C and the liquid level at more than 50%. Since camphor wood has a greater density than poplar wood and is difficult to pulp, in the pulping process of the embodiment of the present invention, a wood chip penetrant is added to the liquid impregnator according to its characteristics, and the extrusion ratio of the extruder is optimized to reasonably control the temperature of the reaction chamber.

[0041] Because camphor wood chips have a high density (0.43-0.56g / cm 3 ), the liquid medicine is difficult to penetrate, and the chemical consumption and pulping energy consumption are high. After adding the wood chip penetrant in the impregnator, the embodiment of the present invention promotes the rapid and uniform penetration of the liquid medicine, and the softening effect of the wood chips is good. For example, adding 1kg / ton pulp can reduce the amount of chemicals by 10% and the pulping energy consumption by 10-15%. After the liquid medicine and the wood chips are evenly mixed, they enter the reaction chamber. In order to make the wood chips mildly chemically treated, the temperature is reduced from the traditional 70-80℃ to 40-50℃, and the time is shortened from 60 minutes to 30-35 minutes. The fiber swelling effect is weak (according to experimental statistical data, the amount of chemicals can be reduced by 10% and the pulping energy consumption can be reduced by 10-15%), the pulping efficiency is improved, and the pulping yield can be increased by 1.0-1.5 percentage points.

[0042] In the embodiment of the present invention, the material produced by the reaction is refined by a first-stage pressure mill, and then enters a dewatering press for dewatering and pressing, and then the pulp after dewatering and pressing is refined by a second-stage pressure mill. During the refining process, the pressure of the first-stage pressure mill and the acceleration of the second-stage pressure mill can be controlled; during the dewatering and pressing process, the load of the dewatering press and the dryness of the pulp after dewatering and pressing must be controlled.

[0043] The process control of chemical mechanical pulp pressure mill is one of the keys to pulp quality. The first stage mill is mainly used to further crush and separate the wood chips (filaments) after extrusion and tearing. According to the physical properties of camphor wood chips, the pressure of the first stage mill is preferably controlled at 110-130kPa, and the pressure mill spacing can be set to 0.12mm (grinding discs are selected as 50127 models); the second stage refining is to process the raw materials into pulp that fully meets the quality standards. The acceleration of the second stage mill is preferably controlled at 50-60ACC%, and the pressure mill grinding discs can be selected as 040 models, and the pressure mill grinding disc spacing is set to 0.10mm.

[0044] In addition, the operation load of the dewatering and pressing after the one-stage pressure mill refining operation can be controlled at 60-70%, and the dryness of the pulp after dewatering and pressing is more than 37%. The pulp refining of the embodiment of the present invention can achieve a breaking length of more than 2.4 km and a fiber bundle of 0.5-1.0%.

[0045] In the embodiment of the present invention, the pulp obtained by grinding is sent to the de-submergence tank for de-submergence and standby use. The de-submergence tank controls the liquid level, temperature and concentration; the prepared pulp is sent to the pressure screen for screening operation, and the good pulp is screened out and sent to the double-net thickener for concentration and dehydration. During screening, the pressure of the pressure screen, the inlet and outlet pressure difference, and the ratio of slag to pulp are controlled. When the pulp is concentrated, the inlet concentration, the number of revolutions of the thickener, etc. are controlled. The concentrated pulp is sent to the pulp storage tower for storage and standby papermaking.

[0046] In a preferred embodiment of the present invention, the liquid level in the de-latching pool is controlled at 60-80%, the temperature is controlled at 60-70°C by low-pressure steam, and the concentration is controlled at 4.0-5.5%. Optimized, in the screening operation of the pressure screen, the screen gap of the pressure screen is preferably 0.23mm, the pressure is controlled at 200-210kPa, the pressure difference between the inlet and outlet is controlled at 90-100kPa, the flow ratio of the slag slurry to the good slurry is controlled at 15-20%, and the operating load is controlled at 60-70%. As a preference, the speed of the double-net thickener is specifically controlled at 11-13RPM, the inlet slurry concentration is controlled at 4.0-5.0%, and the outlet slurry concentration is controlled at 12-14%.

[0047] The embodiment of the present invention formulates the process flow and process parameters for extracting camphor oil and pulping according to the material characteristics of camphor wood, etc., to efficiently extract camphor oil, and pulp the camphor wood chips that have been boiled with camphor and camphor oil. Practice shows that the whiteness of the obtained pulp can be 29±1% ISO, and the dust is not higher than 700mm 2 / kg, and the freeness is controlled at 260-320ml. The camphor wood sodium hydroxide natural chemical mechanical pulping process described in the embodiment of the present invention has low pulping cost and good pulp quality, which can fully meet the needs of high-grade paper production, can alleviate the tension of wood raw materials to a certain extent, save limited wood resources, and greatly improve the extraction rate of camphor oil and camphor, which is conducive to promotion and application.

[0048] In order to better understand the technical content of the present invention, the following specific examples are provided to further illustrate the present invention. In the following examples, the raw materials used are all commercially available. Among them, the wood chip penetrant is a polyethylene glycol fatty acid ester penetrant with a density of 1.00-1.05 g / cm at 25°C. 3 ; The pH value of the original solution is 5.0-9.5, and the penetration capacity is: 1.5g / L aqueous solution <10s.

[0049] Embodiment 1:

[0050] A natural color chemical mechanical pulping process for high-efficiency oil extraction of camphor wood using sodium hydroxide, comprising the following preparation steps:

[0051] Step A: Take camphor wood and perform peeling, chipping, screening, washing and dehydration operations. After screening, wood chips (density 0.43-0.56g / cm 3) length is controlled to be 12-40mm; the thickness of the wood chips is controlled to be 3-6mm; by mass percentage, the qualified rate of the wood chips is controlled to be more than 70%, the bark rate is less than 0.2%, and the moisture content of the camphor wood chips is 30-50%.

[0052] Step B, put the camphor wood chips of step A into a pre-steaming bin for softening treatment, heat the first pre-steaming bin to 80-85°C with steam for 15 minutes, then enter the extruder for extrusion and tearing, the extrusion load of the extruder is controlled at 70-85%, and the extrusion ratio is 1:2.8; then put the extruded and torn wood chips into the first distillation pot and pass water vapor for distillation, camphor oil enters the cooler from the top of the cooking pot along with the steam to condense into liquid, flows into the enamel barrel to separate camphor and camphor oil, and the separated water is sent to the steamer for recycling. The distillation temperature is controlled in two stages, and the primary distillation temperature is controlled in two stages, the first stage is distilled at 110-115°C for 1 hour, and the second stage is distilled at 160-170°C until no camphor oil is precipitated.

[0053] Step C, placing the camphor oil obtained in step B into a 2# distillation pot for secondary distillation, controlling the temperature at 180-200° C. and the steam pressure at 0.75-1.5 MPa; repeatedly purifying and distilling the filtrate 3-4 times until no camphor is precipitated, thereby obtaining pure camphor oil and camphor, wherein the purity of the camphor oil after secondary distillation and purification reaches 99%.

[0054] Step D, sending the camphor wood chips treated by distillation in step B into a single screw dehydrator for dehydration, and then transporting them to a 2-stage pre-steaming bin for steaming, heating the 2-stage with steam to 85-90° C. for 30 minutes, with low-pressure steam of 0.4-0.6 MPa; and then sending them into a 2-stage wood chip extruder for extrusion, tearing and dehydration with a metering screw, and the extrusion load of the extruder is controlled at 60-70%.

[0055] The spiral dehydrated material prepared in step E and step D is transported to a stage 1 liquid prepreg device to add sodium hydroxide and a wood chip permeator for uniform mixing, and then transported to a reaction bin for chemical reaction. After the reaction is completed, it enters a steaming pipe for heating and is transported to a feeder by a pressure conveying screw; the amount of sodium hydroxide added is 50 kg / ton of pulp, and the amount of wood chip permeant is 0.5 kg / ton of pulp. The liquid level in the reaction bin is controlled at 60-80%, the temperature is controlled at 40-50°C, the time is 30-35 minutes, the temperature of the steaming pipe is controlled at 80-90°C, and the liquid level is controlled at more than 50%.

[0056] Step F, grinding the material prepared in step E with a pressure mill, the pressure of the pressure mill is controlled at 130 kPa, the pressure mill spacing is set to 0.12 mm, and the grinding plate is selected as model 50127; entering the dehydration press for dehydration and pressing, the operating load of the dehydration press is controlled at 60-70%, and the pulp dryness after dehydration and pressing reaches more than 37%;

[0057] The dehydrated and squeezed pulp was subjected to a two-stage pressure mill refining operation, the second-stage pressure mill acceleration was controlled at 60ACC%, the pressure mill grinding plate was selected as 040 model, and the pressure mill grinding plate spacing was set to 0.10mm; the obtained pulp breaking length reached 2.47km, and the fiber bundle was 0.9%.

[0058] Step G: sending the slurry prepared in step F to a de-submersible tank for de-submersible standby use, the liquid level in the de-submersible tank is controlled at 60-80%, the temperature is controlled at 60-70° C. by low-pressure steam, and the concentration is controlled at 4.0-5.5%.

[0059] Step H, sending the slurry prepared in step G to a pressure screen for screening operation. During the screening operation of the pressure screen, the screen gap of the pressure screen is preferably 0.23 mm, the pressure is controlled to be 200-210 kPa, the pressure difference between the inlet and outlet is controlled to be 90-100 kPa, the flow ratio of the slag slurry to the good slurry is controlled to be 15-20%, and the operating load is controlled to be 60-70%; the good slurry is screened out and sent to a double-net concentrator for concentrating and dehydrating. The speed of the double-net concentrator is controlled at 11-13 RPM, the double-net mesh is preferably 80 mesh, the inlet slurry concentration is controlled at 4.0-5.0%, and the outlet slurry concentration is controlled at 12-14%.

[0060] Step I: sending the slurry prepared in step H to a slurry storage tower for storage so as to be used for papermaking.

[0061] Example 1 The extraction rate of camphor and camphor oil was 96%, and the purity of camphor oil after secondary distillation was 99%. The quality of the prepared slurry is shown in Table 1 below:

[0062] Table 1 Properties of the slurry prepared in Example 1

[0063]

[0064] It can be seen from Table 1 above that the various physical indicators of the pulp can meet the quality requirements of natural color packaging paper.

[0065] Embodiment 2:

[0066] A natural color chemical mechanical pulping process for high-efficiency oil extraction of camphor wood using sodium hydroxide, comprising the following preparation steps:

[0067] Step A: Take camphor wood and perform peeling, chipping, screening, washing and dehydration operations. After screening, wood chips (density 0.43-0.56g / cm 3 ) length is controlled to be 12-40mm; the thickness of the wood chips is controlled to be 3-6mm; by mass percentage, the qualified rate of the wood chips is controlled to be more than 70%, the bark rate is less than 0.2%, and the moisture content of the camphor wood chips is 30-50%.

[0068] Step B, put the camphor wood chips of step A into a pre-steaming bin for softening treatment, heat the first pre-steaming bin to 80-85°C with steam for 15 minutes, then enter the extruder for extrusion and tearing, the extrusion load of the extruder is controlled at 70-85%, and the extrusion ratio is 1:2.8; then put the extruded and torn wood chips into the first distillation pot and pass water vapor for distillation, camphor oil enters the cooler from the top of the cooking pot along with the steam to condense into liquid, flows into the enamel barrel to separate camphor and camphor oil, and the separated water is sent to the steamer for recycling. The distillation temperature is controlled in two stages, and the primary distillation temperature is controlled in two stages, the first stage is distilled at 110-115°C for 1 hour, and the second stage is distilled at 160-170°C until no camphor oil is precipitated.

[0069] Step C, placing the camphor oil obtained in step B into a 2# distillation pot for secondary distillation, controlling the temperature at 180-200° C. and the steam pressure at 0.75-1.5 MPa; repeatedly purifying and distilling the filtrate 3-4 times until no camphor is precipitated, thereby obtaining pure camphor oil and camphor, wherein the purity of the camphor oil after secondary distillation and purification reaches 99%.

[0070] Step D, sending the camphor wood chips treated by distillation in step B into a single screw dehydrator for dehydration, and then transporting them to a 2-stage pre-steaming bin for steaming, heating the 2-stage with steam to 85-90° C. for 30 minutes, with low-pressure steam of 0.4-0.6 MPa; and then sending them into a 2-stage wood chip extruder for extrusion, tearing and dehydration with a metering screw, and the extrusion load of the extruder is controlled at 60-70%.

[0071] The spiral dehydrated material prepared in step E and step D is transported to a stage 1 liquid prepreg device to add sodium hydroxide and a wood chip permeator for uniform mixing, and then transported to a reaction bin for chemical reaction. After the reaction is completed, it enters a steaming pipe for heating and is transported to a feeder by a pressure conveying screw; the amount of sodium hydroxide added is 55kg / ton of pulp, and the amount of wood chip permeant is 1.0kg / ton of pulp. The liquid level in the reaction bin is controlled at 60-80%, the temperature is controlled at 40-50°C, the time is 30-35 minutes, the temperature of the steaming pipe is controlled at 80-90°C, and the liquid level is controlled at more than 50%.

[0072] Step F, grinding the material prepared in step E with a first-stage pressure mill, the pressure of the first-stage pressure mill is controlled at 120 kPa, the pressure mill spacing is set to 0.12 mm, and the grinding plate is selected as model 50127; entering the dehydration press for dehydration and pressing, the operating load of the dehydration press is controlled at 60-70%, and the pulp dryness after dehydration and pressing reaches more than 37%;

[0073] The dehydrated and squeezed pulp was subjected to a two-stage pressure mill refining operation, the second-stage pressure mill acceleration was controlled at 50ACC%, the pressure mill grinding plate was selected as 040 model, and the pressure mill grinding plate spacing was set to 0.10mm; the obtained pulp had a breaking length of 2.42km and a fiber bundle content of 0.5%.

[0074] Step G: sending the slurry prepared in step F to a de-submersible tank for de-submersible standby use, the liquid level in the de-submersible tank is controlled at 60-80%, the temperature is controlled at 60-70° C. by low-pressure steam, and the concentration is controlled at 4.0-5.5%.

[0075] Step H, sending the slurry prepared in step G to a pressure screen for screening operation. During the screening operation of the pressure screen, the screen gap of the pressure screen is preferably 0.23 mm, the pressure is controlled to be 200-210 kPa, the pressure difference between the inlet and outlet is controlled to be 90-100 kPa, the flow ratio of the slag slurry to the good slurry is controlled to be 15-20%, and the operating load is controlled to be 60-70%; the good slurry is screened out and sent to a double-net concentrator for concentrating and dehydrating. The speed of the double-net concentrator is controlled at 11-13 RPM, the double-net mesh is preferably 80 mesh, the inlet slurry concentration is controlled at 4.0-5.0%, and the outlet slurry concentration is controlled at 12-14%.

[0076] Step I: sending the slurry prepared in step H to a slurry storage tower for storage so as to be used for papermaking.

[0077] The camphor and camphor extraction rate obtained in Example 2 reached 96%, the average fiber length after pulping was 0.84 mm, the fiber width was 25.6 μm, the fiber aspect ratio was about 40, the freeness CSF was 314 ml, the breaking length was 2.42 km, and the tear index was 2.7 mN.m 2 / g, fiber bundle content 0.5%, bulk thickness 2.90cm 3 / g, whiteness 28.86% ISO, dust 300mm 2 / kg.

[0078] It can be seen from the above embodiments that the embodiments of the present invention disclose a pulping process for a natural color chemical mechanical pulp of sodium hydroxide for efficient oil extraction from camphor wood. The preparation steps of the chemical mechanical pulp are as follows: camphor wood is peeled, chipped, screened, washed and dehydrated, the camphor wood chips are placed in a pre-steaming bin for pre-steaming and softening treatment, and then placed in an extruder for extrusion and tearing, the extruded and torn camphor wood chips are placed in a distillation pot for segmented distillation until the condensate is free of oil droplets; the wood chips from which camphor and camphor oil have been extracted are then sent to a pre-steaming bin for pre-steaming treatment, sent to a single screw dehydrator for dehydration, and then steamed for a second time and sent to a 2-stage extruder for extrusion and tearing, the wood chips after the 2-stage extrusion enter a 1-stage prepreg device, and are mixed with the 1-stage prepreg liquid and then sent to a reaction bin for treatment, sent to a 1-stage pressure pulping machine for pulping, cyclone separation, dehydration by a dehydration press, 2-stage pressure mill for high-concentration pulping, de-submergence tank for de-submergence, pressure screen screening, and double-net concentrator for concentration to obtain a finished pulp, which is then sent to a pulp storage tower for storage and used as papermaking pulp. The pulping process for sodium hydroxide natural color chemical mechanical pulp for efficient oil extraction from camphor wood provided in the embodiment of the present invention formulates the process flow and process parameters according to the material characteristics of camphor wood, etc., has high camphor and camphor oil extraction rates, low pulping costs, and good pulp quality, which can meet the demand for natural color packaging paper, thereby solving the problems of low camphor and camphor oil extraction rates, the influence of camphor oil in camphor wood chips on the biochemical treatment of pulping wastewater, the resin barrier of camphor wood pulping for papermaking, and the difficulty in pulping due to the high density of camphor wood chips.

[0079] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. The above is only a preferred implementation of the present invention. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, ordinary technicians in this technical field can make several improvements, modifications or changes without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. A natural color chemical mechanical pulping process for camphor wood sodium hydroxide, characterized in that: The following steps are involved: S1, pre-steaming and softening the camphor wood chips at 80-85°C, then extruding and tearing them with a wood chip extruder, and then performing a segmented distillation process using water vapor, wherein the segmented distillation process temperature control includes: distilling at 110-118°C for at least 1 hour in the initial stage and distilling at 140-180°C in the final stage until no camphor oil is precipitated, so that the extraction rate of camphor oil is above 96%; S2, dehydrating the camphorwood chips after the segmented distillation treatment, and then steaming at 85-90°C, and then extruding, tearing and dehydrating, and the obtained dehydrated material is impregnated with a sodium hydroxide solution containing a wood chip penetrant to react; S3. The reacted material is subjected to pulping operation by a first-stage pressure mill, and then dewatered and pressed, and the pulp after dewatering and pressing is subjected to a second-stage pressure mill pulping operation; the pressure of the first-stage pressure mill is controlled to be 110-130 kPa; the operating load of the dewatering and pressing after the first-stage pressure mill pulping operation is controlled to be 60-70%, and the pulp dryness after dewatering and pressing is more than 37%; the acceleration of the second-stage pressure mill is controlled to be 50-60% ACC; after dehydration, delatency removal, screening and concentration, a natural color chemical mechanical pulp is obtained.

2. The natural color chemical mechanical pulping process of camphor wood sodium hydroxide according to claim 1, characterized in that: In step S1, the length of the camphor wood chips is controlled to be 12-40 mm, the thickness is controlled to be 3-6 mm, and the moisture content is controlled to be 30-60 wt %.

3. The natural color chemical mechanical pulping process of camphor wood sodium hydroxide according to claim 1, characterized in that: The extrusion tearing load in step S1 is 70-85%, and the wood chip extrusion ratio is set at 1: (2.5-3).

4. The natural color chemical mechanical pulping process of camphor wood sodium hydroxide according to any one of claims 1 to 3, characterized in that: The step S1 also includes: distilling and purifying the camphor oil mixture obtained by the segmented distillation process, and controlling the temperature at 155-200°C.

5. The natural color chemical mechanical pulping process of camphor wood sodium hydroxide according to claim 4, characterized in that: In step S2, the amount of sodium hydroxide used is 50-55 kg / ton of pulp, and the amount of wood chip penetrant used is 0.5-1.0 kg / ton of pulp. The reaction temperature is controlled at 40-50° C. and the reaction time is 30-35 minutes.

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